JPH045341B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial applications The present invention provides corresponding adsorption and/or desorption etc.
Find the temperature line and calculate the surface area, pore size distribution, and
and various morphologies of the solid such as average pore volume.
adsorbed by a solid in such a way as to determine its physical properties.
or determine the amount of gas or gases desorbed.
and a method and apparatus for measuring the same. Conventional technology Catalysts, catalyst supports, pigments, clays, minerals and
Morphological or structural properties of solids such as composite materials
The measurement of sex has long been an unsolved problem in analytical science.
It was a goal I was on track for. For example, very useful morphological properties of certain solids
One of these is surface area. Most widely used for surface area measurements
One of the most commonly used technologies is gas adsorption technology.
be. In this gas adsorption technology, a theoretical model
In this model, the
The surface of the test solid (i.e. adsorbent) is
a single layer of tightly packed molecules of adsorbent)
It is considered to be covered by So above
The amount of adsorbed material in a single layer (usually milliliter)
or expressed in ml), then
The area covered by the single layer, for example, the area within the single layer.
It can be easily calculated from the product of the number of children multiplied by the cross-sectional area of each molecule.
can be calculated. In 1938, Branauer,
Emmett and Teller are the adsorption isotherms of adsorbed materials.
To determine the amount of adsorbed material in a single layer from the line
proposed a mathematical formula called the BET formula (J.Am.Chem.
See Soc.Vol.60, 2309). Here, the adsorption isotherm is
Relative pressure or equilibrium pressure of adsorbed material at constant temperature
Plots the amount of adsorbed material adsorbed onto the solid against the force.
This is the curve that was to determine surface area
In order to use the BET formula accurately, at least
Determine the point on the adsorption isotherm at which “single layer capacity” occurs.
of sufficient numbers on the adsorption isotherm to be able to
Data points must be obtained. Here, "single layer volume"
"Amount" is one variable in the BET formula,
A single layer of closely packed adsorbed molecules is the adsorbent.
represents a point on the adsorption isotherm on the surface of this
Monolayer capacity is generally between about 0.8 and 2.5 adsorbed
Since it occurs due to the partial pressure of the agent, the surface area can be calculated using the BET formula.
over at least this partial pressure range to make it possible.
It is desirable to know the adsorption isotherm. however
Significant is the adsorbent partial pressure in the range 0 to 1.
, the total adsorption isotherm range (adsorbent partial pressure is arbitrary)
of the adsorbed material under a combination of constant volume and temperature conditions.
Equilibrium of the adsorbed material as a fraction of the pressure at which condensation occurs
) is one way to express pressure, but only the surface area
Although it is not necessary to know for the purpose of determination, the total adsorption isotherm
The embodied information is, nevertheless, as described below.
This is very useful for other reasons. Therefore, it has the ability to determine the total adsorption isotherm.
There is a motivation to develop analytical methods that Adsorption isotherm
is usually carried out using two common methods: gravimetric
method and volumetric method. In gravimetric methods, adsorption at equilibrium pressure is
Measure the amount of gas using a microbalance.
However, this gravimetric analysis method requires
(e.g. liquid nitrogen temperature
(It is not easy to control the sample with
Difficult to achieve effective temperature control
or complicated to achieve the high sensitivity required for measurements.
There are disadvantages such as the need for expensive equipment. this
In contrast, volumetric analyzers are simple and inherently
Highly reliable. In volumetric analysis, the weight of the gas adsorbed
The volume is measured instead. The capacitance analyzer is
For example, using nitrogen at a temperature of -195℃ as the adsorbent.
Ru. This type of device typically uses a gas storage unit.
Known volumes such as bolts and bullets or pipettes
V₁It has a capacitance meter called a capacitance meter unit.
Exhaust or vacuum source connected in parallel to fixed equipment
It is composed of. Capacitance meter unit alternates
A vacuum source or gas reservoir is connected to the
Can be connected to storage unit. On the other hand, capacity
The meter unit is connected to the sample unit via another stopper.
i.e. the known volume V holding the test solid₂room
connected in series. Operate various stop handles
By doing so, the capacitance meter and sample unit are
The evacuated and evacuated volume meter
It will be sealed and separated from the cooking room. After that, nitrogen
gradually moves from the gas storage unit to the capacitance meter unit.
flows and fills the volumetric unit. Capacity meter unit
When the capacity is filled, operate the stopcock again to increase the capacity.
Completely seal the meter unit and measure internal nitrogen pressure
do. Constant pressure P in the volumetric meter₁Once achieved,
Open the stop that separates the sample chamber and volume meter.
and nitrogen in the capacitance meter.₂into the sample chamber and expand it.
let Here, both the sample chamber and the volume meter are in the third volume.
Product V₃(i.e. V₁+V₂). Volume V₃internal pressure
When the force is constant and adsorption equilibrium is indicated
Then, measure the pressure. Using this equilibrium pressure,
N remaining in the gas phase₂Calculate the number of moles of
N adsorbed on solids₂The number of moles of is the volume of the capacitance meter V₁
N that initially existed within₂to the number of moles of , the volume V₂
N in the sample chamber of₂is equal to the sum of the number of moles of
Volume after equilibrium V₃gas phase N within₂less than the number of moles of
(In the initial cycle, the volume V₂number of moles in
is zero, but increases with successive cycles
do). N adsorbed at a specific equilibrium pressure₂set of quantities of
The combined data constitute a single point on the adsorption isotherm.
Repeat the above steps for other points on the adsorption isotherm.
seek. In successive cycles, the sample chamber
The pressure inside increases, and eventually the sample solidifies at atmospheric pressure.
Condensed N of the body₂Saturation occurs due to paraphrase
free space within the sample and sample holder.
In N₂Condensation occurs. according to common practice
For example, in the case of surface area measurements, approximately 8 points on the adsorption isotherm
data points are generated. Generally, pressure equilibrium is achieved.
Each data point takes one hour to complete. However,
Needless to say, this method
It takes a very long time and you have to wait until it reaches equilibrium.
Two delays are involved for each data point, and adsorption etc.
Hotline data points are generated on a discrete basis. Na
For more information on how to do this, please visit Surfice Technology.
(Surface Technology) Vol.4, pp. 121-160
(1976) Dollimore.D., Sponner, P.,
and Turner, A.’s paper “The BET Method
of Analysis of Gas Absorption Data and Its
Relevance to The Calculation of Surface
Areas”. The discontinuous volumetric gas sorption unit is
Automate the opening and closing of the sample chamber and capacity meter unit.
This has been improved by increasing the number of points.
Furthermore, the equilibrium time was determined experimentally and automatically simulated.
the stem to respond to a preset equilibration time.
The time required for equilibrium can be determined by programming
It is shortening the time. However, this
The discontinuous nature of the device's operation is not changed.
overly large data points to obtain relatively few data points.
High latency is still required. Bosch and Peppelenbos are
Bu Physics: Scientific Physics
Instruments (Journal of Physics E:
Scientific Instruments) Vol.10, pp. 605-608
(1977) to determine the data points on the adsorption isotherm.
We propose a dynamic method for Follow this method
For example, the adsorbed material in the gas phase is
So-called constant volumetric flow rate (e.g. about 1 at a partial pressure of about 0.25
cm³STPmin^-1) with a known volume and temperature (e.g.
(e.g., liquid nitrogen temperature) into an evacuated sample chamber.
It will be done. The above constant volume flow rate allows the adsorbed material to pass through the capillary tube.
This is achieved by introducing the sample into the sample chamber through the
The amount of adsorbed material adsorbed by the adsorbent is determined by the time
In contrast, the pressure increase in the sample chamber in the presence of the adsorbent sample
It is calculated by comparing the additions. In addition
Blank test or blank cycle (i.e.
(measurement when no adsorbent sample is present in the sample chamber)
pressure increases as a function of time. adsorption
When a medium is present, the adsorbed gas is partially absorbed.
blank and to reach a certain pressure.
It takes more time than testing. However,
is adsorbed by the sample (Va) at a specific pressure.
The volume of gas or gas contained in the gas is calculated from the following formula:
Ru. [Va=φV(STP)△t]_p In the above formula, φV(STP) is at standard temperature and pressure.
Volumetric flow rate through the capillary (cm³min^-1), △
t reaches the pressure P compared to the blank test.
This is the extra time, expressed in minutes, required for capacity
The product flow rate is calculated for a single data point on the adsorption isotherm.
is treated as constant, but in reality,
As acknowledged on page 608 of the above paper,
For example, when nitrogen is used as the adsorbent, the
rather than thereby generating a partial adsorption isotherm.
This also requires quite complex calculations. The method further includes adjusting the flow rate or
Others due to using capillary tubes to control
There are drawbacks. For example, the properties of a fixed capillary are
Varies with temperature and environmental conditions. For example, environmental conditions
fluctuations in the temperature, resulting from thermal expansion or contraction of the capillary
As a result, fluctuations occur in the flow rate of the adsorbent. Fixed
capillary tubes are difficult to fabricate within a certain flow rate range.
Not only is it difficult, but also the solid adsorbent is used during desorption.
They may become clogged, or they are brittle and therefore frequently
Frequent replacement is required. In addition, fixed capillaries
Can be adjusted to control the body's flow rate
However, it depends on the type of adsorbent sample used.
It is not possible to give optimal conditions for Sara
Importantly, the volumetric flow rate is assumed to be constant.
For example, 500m²/g (gram)
Adsorption isotherms and
Large errors (e.g. 10 to 15
% or more) is the point of intervention. This way
Such an error increases as the surface area of the sample increases.
The longer it takes to reach equilibrium pressure
It comes from the fact that Therefore, for a given weight
The larger the surface area of the sample, the higher the flow rate.
must be correspondingly low, and the flow rate is low.
If so, reduce the ID (inner diameter) of the capillary accordingly.
environmental conditions.
The sensitivity of flow rate to fluctuations in
I end up. Environmental requirements at the flow rates mentioned above
Even if we ignore the fluctuations induced by factors, the adsorption isotherm
in the sample holder when approaching the higher partial pressure above.
The back pressure of the adsorbed material generated during the process also changes or reduces the flow rate.
Make it less. The 606-page paper by Bosch et al. cited above contains approximately
Even at a partial pressure of 0.2, the flow rate will decrease by 0.6% due to back pressure.
It is recognized that This kind of back pressure causes
The volumetric flow rate variation caused by the high point on the adsorption isotherm
It becomes even larger when collecting data in the field.
As a result, the error gradually increases over the entire experimental process.
Either you have to accept that it will become, or
Also, in connection with blank tests and sample measurements,
The above changes can be done mathematically using complex techniques.
It is required to compensate for the Furthermore, the flow rate of the adsorbed material is set to be larger than the equilibrium adsorption amount.
Must be maintained so that it does not become
From a practical point of view it is not possible to obtain a complete adsorption isotherm.
Therefore, there are no inherent restrictions on the use of capillary tubes.
There are limits. For example, in a capillary system, the flow rate is
It is proportional to the pressure drop across the capillary. I want to
Since the initial flow rate is very low, the back pressure reduces the flow rate.
further decreases to about 70 to 80% of the adsorption isotherm.
The flow rate becomes almost non-existent after reaching
cormorant. Innes US Pat. No. 2,729,969 describes Bosch
A capillary method very similar to others has been disclosed
ing. However, as stated in this patent specification,
The flow rate of the adsorbent may be controlled or
Is a capillary tube used to adjust the
, similar drawbacks as mentioned above arise from it.
There is. Adsorbent introduction is approximately 7 to 10 c.c./min.
is carried out in the partial pressure range of approximately 0.1 to 0.3 at a flow rate of
Ru. It is clear from the statement in column 6, line 45 and below of the above specification.
small pores (thus high surfaces)
10c.c./min.
Equilibrium pressure state does not occur even at a flow rate of 7 c.c./min.
I didn't know. In other words, the flow rate is determined by the equilibrium adsorption of the adsorbed material.
greater than quantity or velocity. however,
To reduce this flow rate, a smaller diameter
A large capillary tube must be used;
is the response to flow fluctuations induced by environmental conditions.
Increased flow sensitivity or also use lower pressures
However, in that case, the induced
The sensitivity of the flow rate to the flow fluctuations caused by
Ru. In addition, in column 4, line 5 and below of the same specification, there are
The amount is described as being constant as shown in Figure 4.
Ru. However, FIG. 4 of this patent specification shows
Only 150 seconds of flow time using only 11 data points
It only shows the interval. Also, Bosch et al.
A similar flow time using 6 data points
Plot the curve and prove the claim that the flow rate is constant.
I'm trying to uphold legitimacy. However, this
None of the data in the single layer capacity range, e.g. 0.8
sufficient to achieve partial pressures in the range of
the flow rate for a period of time, mostly at the initial stage.
to maintain below the equilibrium adsorption capacity of a sample of unknown surface area.
Approximately 4 hours of flow time is required if
There is no evidence that the flow rate is constant over time.
As already mentioned, environmentally induced flow fluctuations
accumulates over a long period of time. Therefore, the capillary
Justifying the claim of constant flow in the method
The data used for the
The operating conditions required for the device to operate satisfactorily
The matter is not reflected. Additionally, the capillary device of Bosch et al.
If you try to use it to ask (for this matter)
(discussed later), the fixed leakage capillary method
However, other serious disadvantages arise. In desorption experiments
The pre-adsorbed gas is connected to a vacuum source
is removed from the surface of the sample through a capillary tube.
During this process, the pressure inside the specimen holder is
decreases over time. Therefore, at both ends of the capillary
The pressure difference at is reduced as a function of time during the course of the desorption experiment.
Do a little. Removes previously adsorbed gas from the sample chamber.
The driving force to remove the air is due to this pressure difference.
Even in partial desorption experiments it takes about
20 to about 40 hours are required. Therefore,
Capillary desorption methods are time consuming and environmentally induced
The volumetric flow rate fluctuations caused by
In this way, the actual
The volumetric flow rate (and therefore the desorption at a given equilibrium pressure)
Complex calculations are required to determine the actual amount of gas deposited.
Surgical correction is required. Furthermore, such an error
Regarding this, there is no description in the above-mentioned document by Bosch et al.
This is because in this literature, desorption is not a concern.
It is the body. Innes' U.S. patent specification includes a capillary tube for removal and removal.
Use of the system is disclosed. But long
Evacuation of the chamber via a capillary tube as mentioned above
Because of the problems associated with this, the inventor decided to
Rather than being desorbed at room temperature, it is adsorbed to the sample at room temperature.
is forced to heat the nitrogen that is present.
Do not put the specimen holder in and out of liquid nitrogen.
This not only complicates the process, but also
Determination of the volume of a system at equilibrium at liquid nitrogen temperature
introduces a noticeable error in Such a discontinuity
, the actual temperature of the sample must deviate from the liquid nitrogen temperature.
It is closed. And the actual for liquid nitrogen temperature
A deviation of 1°C from the sample temperature will invalidate the test result.
I end up. In summary, the text by Bosch et al. and Innes
In the capillary method disclosed in
temperature and pressure) and below 1 ml/min.
Amount has the meaning defined herein over a given period of time.
is essentially constant. Desorption isotherms are important for the following reasons. That is,
From the data represented by the desorption isotherm, the pore size of the solid sample is
There are various formulas that can calculate the diameter distribution.
Because it is known. Here, the desorption isotherm and
is the solid state for the equilibrium pressure of the desorbed material at a constant temperature.
previously adsorbed gaseous substances that are desorbed from the body
(herein referred to as desorbent)
It is a curved line. The desorption isotherm is the adsorption isotherm.
It differs from the line in the following points. That is, the former is a desorbed agent.
Starting from a saturated solid, the pressure on the solid is
By gradually decreasing toward absolute vacuum,
This is a point that is required. In contrast, the adsorption isotherm
The line starts from the evacuated solid sample and starts from the evacuated solid sample.
Adsorption of the gas phase in contact with the sample until saturation of
The pressure of the agent is increased. In addition, the adsorption isotherm
And adsorption isotherm is a superordinate concept of desorption isotherm.
It's used. Sorption isotherm due to gas-solid interaction
At least a portion of the line's desorption trajectory is similar to the adsorption trajectory.
It is also located at a high position on the isotherm. In this way,
The phenomenon in which the landing trajectory does not trace the adsorption trajectory of the isothermal line is one thing.
This is generally called hysteresis. this hysteria
The two most common forms of cis are closed-loop and open-loop.
It is a pool. In closed-loop hysteresis behavior
The desorption trajectory of the isotherm shows that the adsorption occurs at a certain low relative pressure.
Join to trajectory. Closed-loop hysteresis is typically
It is related to the porosity of the test sample. For example, desorption isotherm
At the starting point of the line, the pores of the sample are filled with the desorbed material.
Saturated and full. Desorption process occurs
and the desorbed agent present in the pores due to capillary action.
The desorption of is delayed and therefore the filling of the pores during adsorption
compared to the pressure that caused the hole to evacuate.
lower pressure is required. This delay causes sorption
Expressed as a closed-loop hysteresis characteristic of the isotherm
It is. Also, the open loop hysteresis is equal to
This is caused by the fact that the desorption trajectory of the warm wire does not intersect with the adsorption trajectory.
This is due to this. Open-loop hysteresis is
It is usually related to the amount of measurable irreversible adsorption. child
Irreversible adsorption, such as
Gas and solid samples in sorption called chemisorption
This is due to the reaction. Therefore, when attaching and detaching
, less material is desorbed than was initially adsorbed.
Therefore, there is an opening in the adsorption isotherm.
This creates a loop. Furthermore, by intentionally inducing chemisorption,
You can learn a lot about the surface of solid samples.
Ru. For example, support by chemisorption with catalyst particles.
The body uses a gas-phase adsorbent that does not perform chemical adsorption.
and the size of the micro-table placed on the above support.
To determine the % dispersion and surface area of catalyst particles of
School sorption can be used. Other information in a virtually complete sorption isotherm
used to calculate total pore volume, average pore size or pore diameter.
and the shape of the hole (e.g. slit or circular).
can be determined. In the above discussion, the narrow line segment of the sorption isotherm
In order to obtain a virtually complete curve image of the total sorption isotherm,
A few attempts were discussed in detail. this
As is clear from the discussion, it is possible to quickly and accurately
How a complete sorption isotherm can be generated
Or the device may be related to the proposals of Bosch et al. or Innes.
considered to have considerable advantages over the conventional capillary method.
available. Another method for determining adsorption isotherms is the anal
Analytical Chem.
Nelson, Vol. 30, pp. 13-87 (1958) and
Eggersten's paper "Adsorption Measurement
By Continuous Flow Method”
Ru. In this method, nitrogen and helium
From a gas flow, nitrogen is used as an adsorbent at liquid nitrogen temperature.
It is then adsorbed and taken out when the sample is heated. released
Nitrogen is measured by thermal conductivity. I want to
Therefore, the amount of gas adsorbed is
Continuous flow at atmospheric pressure rather than by volumetric measurement
Determined by concentration measurements in the system. this
The method uses a chromatograph to determine adsorption isotherms.
It is called the Rahui method. This is called chromatography.
This is because it is similar to the graphi method. this method
The two requirements are the carrier gas and
and that the adsorbent gas is at a steady flow rate.
Since two types of gas can be mixed on the spot,
be. However, this Ne/sen and other methods
However, flow control is performed by capillary tubes.
Ru. In contrast, analytical chemistry
(Analytical Chem.), Vol.43, No.10, page 1307
Farey and Tucker paper published in (1971)
“Determination of Surface Areas By An
Improved Continuous Flow Method” smell
Instead of a capillary, a series of pressure and mass flow
Attempts to achieve steady flow using a controller
(Furthermore, Bhat, R. and
Indian Jiya by Krishnamoorthy, T.
Indian Journal of Technology
Technology) Vol. 14, p. 170 (1976).
sea bream). The nitrogen flow rate suitable for this experiment is between 2 and
It was 20ml/min. However, the same paper
pass through the detector, as also described on page 1309.
The flow rate depends on the sudden temperature encountered in the adsorption/desorption cycle.
It fluctuates instantaneously due to changes. Farey et al.'s chromatog
This problem does not arise with the Lahuy method. The reason is,
Each data point spans a relatively short period of time (e.g. 20 minutes)
generated on a discontinuous basis, discontinuous peaks,
During the generation of data points, such fluctuations are caused by the mass flow rate.
Because it can be compensated by the controller
It is. Short duration required for each peak
Errors caused by long-term environmental changes
Accumulation can also be avoided. In contrast, the method of the present invention
Now, unless stated otherwise (e.g. adsorption
Approximately 4 hours in case and 12 hours in case of desorption
) Small uncontrolled mass flow during the analysis process.
Even possible fluctuations can be removed.
Ru. In the present invention, in order to achieve this objective,
Mass flow rates in the range of 0.2 to 0.4 ml/min are typical.
The fact that it is used is also taken into account. like this
Low flow rates are typically suitable for large surface area materials.
with a very low equilibrium adsorption or desorption amount.
Supplying gas to the adsorbent in a large amount or desorbing medium
Is it advantageous to avoid desorption of gas from
It is et al. The reason is that conventional mass flow controllers
Typically, gas flow is metered in
of gas passing through the controller as a means to
Due to the fact that thermal conductivity is used
It is. This problem is a problem with conventional mass flow controllers.
undesirable control in the sensing element of the flow meter.
due to environmental temperature fluctuations that cause cumulative fluctuations.
It becomes even more serious. Furthermore, low pressure and
Due to the low thermal conductivity of the gas at the flow rate, the environment at the flow rate
-induced fluctuations occur and conventional flow and pressure
Contributes significantly to the relative error in flow rate compared to the use of force
do. Therefore, conventional mass flow controllers
are unsuitable for use in carrying out the method of the invention.
It is. Note that the main component of conventional mass flow controllers is
Conventional flow meters and servers form essential components.
Maru valve (thermal response valve) is patented in U.S. Patent No. 3650505,
3851526, 3938384 and 4056975 specifications
It is described in As is clear from the above explanation, the sorption isotherm is
A quick, simple, yet more accurate way to
There is a constant demand for equipment. present invention
was developed to meet this demand.
Ru. Summary of the invention According to one aspect of the invention, the solid adsorbent
How to determine the amount of gaseous adsorbent adsorbed by
In, (a) Provide an evacuated chamber of known volume and insert the gas into the chamber.
Place the released adsorbent sample and maintain it at a known temperature.
Hold, (b) at least a portion of the material to be adsorbed by the adsorbent;
for a period of time sufficient to obtain adsorption of
The sample is accommodated at a qualitatively constant mass flow rate.
In this case, the gaseous adsorbent is introduced into a room where the
The mass flow rate is the average of the above adsorbed material by the above adsorbent.
not larger than the equilibrium adsorption amount and at standard temperature and
Under pressure conditions not greater than approximately 0.7ml/min, (c) when introduced into the room as a function of time.
Set the equilibrium pressure of the above adsorbed material, and
is the sampling chamber pressure, and (d) Pressure in the above-mentioned sampling chamber for the adsorbent, quality of the adsorbent
To achieve the above flow rate and sampling chamber pressure
Apply the above adsorbent at the above sampling chamber pressure for the required time.
stages that correlate with the amount of adsorbed material adsorbed by
A method including the following is proposed. According to another aspect of the invention, the condensed desorbed
desorbed as a gas from a solid desorbent saturated with
In a method for determining the amount of desorbed agent to be desorbed, (a) Contains desorbed material that has been degassed and condensed in advance.
A sample of the desorbent to be desorbed is placed in a chamber containing the desorbent in the gas phase.
The known volume accommodated in equilibrium with the atmosphere and
Set up a temperature chamber, (b) Desorbing the condensed desorbent from the pores of the sample above.
from the desorbent for at least a sufficient period of time to
A known actual amount not greater than the equilibrium desorption amount of the desorbed agent.
said desorbed material from said chamber at a qualitatively constant mass flow rate.
Take out the agent, (c) The amount of time required to remove the desorbed material from the above chamber.
Set the equilibrium pressure of the above desorbed agent as a function,
The equilibrium pressure is the sampling chamber pressure of the agent to be desorbed, (d) Sampling chamber pressure of desorbed agent, mass flow of desorbed agent
volume, and necessary to achieve the above sampling chamber pressure.
The required time is desorbed at the above sampling chamber pressure.
A method is proposed that includes steps that correlate with the amount of desorbent used.
be done. According to yet another aspect of the invention, a solid adsorbent
amount of gas or solid desorbent adsorbed by the sample
Equipment for determining the amount of gas desorbed from a sample
At the location, (1) The solid sample and the gas introduced into the chamber means.
or containing gas removed from said chamber means.
at least one chamber of known constant volume for
chamber means defining a (2) Continuously introducing gas into the chamber means or
means for continuously removing gas from the means; (3) Gas is introduced into or from said chamber means.
as a function of time within the chamber means when taken out
means for setting the pressure of the gas; (4) The above gas or gas being introduced into the above chamber.
Mass flow rate of the above gas being removed from the recording chamber
(a) the mass flow rate of the gas in the room is controlled;
Over the entire partial pressure range of at least about 0.02 to about 1.0
(b) the gas is substantially constant throughout;
During introduction, the equilibrium adsorption amount of gas by the adsorbent sample is
without increasing the temperature, and during the extraction of the above gas.
Less than the equilibrium desorption amount of gas from the desorbent sample
a control means for controlling the (5) The above-mentioned room operator is taking out the above-mentioned gas from the above-mentioned room means.
Gas is exhausted from the stage via the control means described above.
and the means for (6) Keep the known temperature of the gas in the room substantially constant.
An apparatus is proposed comprising means for maintaining the
Ru. Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
explain about. In addition, in Figures 2 and 3
A person skilled in the art will be able to determine what is desirable in actual equipment operation.
Elements that make one think that such things are omitted. This is a book
Simplify the illustration of the invention so that it is already well understood
This is to save the effort of explaining technical details.
Therefore, for example, power supply, solenoid valves
electrical connections, computer-assisted automation, etc.
Certain equipment as may be required is shown in the diagram.
Please note that it has been omitted. Description of preferred specific examples The method of the invention is a dynamic or
This method is characterized by being both a capacitance method and a capacitance method.
The method can be adsorption mode, desorption mode or adsorption mode.
A combination mode of the above two modes followed by a detachment mode.
It can be carried out in the code. The adsorption mode is initially gas or
This is done using substances and solids that exist as
It will be done. Note that in this specification, the above gas is
It is called adsorbent or adsorbent, and it adsorbs solids.
Adsorbent or adsorbent or sample
to be called. During adsorption mode, the adsorbed substance or
The adsorbent is physical in nature.
planned and controlled or physicochemical
can be changed depending on whether it is controlled so that
Ru. As is well known, the adsorption phenomenon is caused by
physical or chemical depending on the temperature used
It can be the result of a physical process. Physical adsorption (sometimes
(Also called Babuen der Waals adsorption)
is the result of a relatively weak interaction between a solid and a gas.
It is a fruit. One of the characteristics of this type of adsorption is that the solid
As a result, all the adsorbed gases are
Remove by evacuation at approximately the same temperature as
The point is that you can. chemisorption (this process
physical adsorption also occurs).
There is also a fairly strong interaction between solid and gas.
Ku. Chemically adsorbed gas is the chemically adsorbed gas.
removed from the solid by evacuation at approximately the same temperature as
initial removal of chemically adsorbed substances.
requires evacuation at a temperature considerably higher than the adsorption temperature.
I can seek it. Typically, during chemisorption, the adsorbent is
Reacts with the adsorbed substance. Therefore, physical absorption
In the case of adsorption, the adsorbed substance has a chemical effect on the adsorbent.
selected in conjunction with the adsorbent to be physically inert.
Ru. Additionally, the amount of gas physically adsorbed at a given pressure is
Since the amount increases with decreasing temperature, the adsorbed
The quality typically varies from about -195°C to
Very low temperature of about 100℃ (e.g. -195℃ to 0℃)
selected to liquefy at a low temperature. Inventor
The adsorbed substance or adsorbent used in the method is:
This is a commonly used method for gas sorption capacity analysis.
Ru. Representative adsorbents commonly used for physical adsorption
Examples include nitrogen, argon, hydrocarbons, e.g.
For example, butane, hexene, benzene, H₂O and
C.O.₂There is. Specifications commonly used to perform chemisorption
It is called chemically adsorbed substance or chemically adsorbed agent.
Typical examples of adsorbents include O₂, CO, CO₂,
H₂O, H₂etc. are included. The adsorbent or sample is
analyzed for its morphological characteristics such as surface area.
It is any solid that you want to be. The method described here
is typically about 0.01 to about 1500, preferably
about 0.05 to about 1200, and more preferably about
0.5 to about 800m²/g surface area and typically
is about 5 to about 550 angstroms, preferably
is about 7 to about 450 angstroms and further
preferably about 9 to about 400 angstroms.
Applicable to samples or specimens with pore size.
Ru. Note that the above pore size range includes Kelvin, which will be described later.
This reflects the inherent limitations in the equation. adsorbed material adsorbed by a certain sample or specimen
Before measuring the amount of a substance, such as nitrogen, oxygen, water vapor, etc.
Remove adsorbed atmospheric gases such as (i.e. gas
The sample is freed by
Purified from purity. This is Orr, C. and
"Fine Particle" by Dallavalle, J.
Measurement”, published by Macmillan Company,
Usage as described on pages 164-204 (1960)
This is achieved by the following method. In addition, the opening of this document
The contents herein are incorporated by reference.
Ru. According to this method, degassing can be performed, e.g.
The material is heated in vacuum at about 110°C to about 600°C (e.g. 300°C).
to 400℃) for about 4 hours to about 12 o'clock.
for a period of time (e.g. 8 to 12 hours)
This is achieved by heating. Sample weight, field
Depending on the case, the density or concentration of the sample can also be
Measurements are made according to customary methods before contact with the material. The equipment in which the adsorption mode is carried out will be described in detail later.
The station is equipped with a chamber that can be evacuated. child
For convenience of explanation, the chamber consists of two parts.
shall be i.e. sample holder and constraints during the experiment.
Equipment conduits that communicate with the sample holder in a manner that does not
The adsorbed material is passed through this tube into the sample holder.
It is passed through and introduced. The volume of the chamber is the conventional capacity
accurate in advance according to the analytical method and ideal gas law.
I decided to. This volume is
subtract the sample volume from the chamber volume to determine the sample density.
It is preferable to correct for sample volume based on
Yes. However, it is very small compared to the volume of the chamber.
When using high surface area samples with small volumes
, the sample volume can be conveniently ignored.
When using the device of the present invention, the sample holder is stopped.
Seal tightly using a gasket, and connect from the pipe section of the room.
Can be removably removed. Therefore, convenience
Regarding the above problem, weighing the sample or specimen,
Venting and exhaust are usually removed from the chamber
carried out in a sample holder, then sealed and evacuated
The sample holder is then connected to the pipe section of the chamber.
is advantageous. For conventional capacitive gas adsorption analysis methods
Therefore, the volume of the sample holder is typically equal to the volume of the sample.
It is selected to be about 10 times to about 200 times the product. this is,
The reference (blank) is corrected for both adsorption and desorption.
Accurately determine the liquid nitrogen level in the liquid bath - empty
Minimize errors that can interfere with pipe capacity values at the air interface.
while minimizing errors in determining sample density.
This is for the purpose of The temperature of the adsorbed substance is also known and remains constant throughout the experiment.
It is preferable to have one. Suction inside the sample holder part of the chamber
The temperature of the adhesive is the temperature of the sample holder part of the chamber.
Typically, the boiling point of the adsorbent at atmospheric pressure is
The temperature is controlled to be within about ±1°C. Therefore,
The temperature of the sample holder in the chamber is also determined. This is
in a liquid bath, preferably at a constant temperature, known to
Achieved by immersing a large part of the specimen holder.
will be accomplished. As a matter of convenience, the atmosphere
To avoid using pressures that exceed pressure, the temperature of the liquid bath should be
The degree of condensation of the adsorbed material is typically near atmospheric pressure.
The temperature is sufficient to produce this thing
is a liquid that controls the temperature of the specimen or specimen holder.
Is the adsorbent in a liquid phase at atmospheric pressure used as a bath?
or at a temperature not higher than the boiling point of the adsorbent at atmospheric pressure.
using a specially formulated liquid that boils at
easily achieved by However, the liquid bath
In certain cases where the liquefied adsorbent
is the impurity in the liquid bath and the temperature of the bath is such that the pure liquefied
may be slightly higher than the boiling point of the adsorbed material.
Ru. As a result, the adsorbent or adsorbed substance becomes saturated.
sum pressure (when the adsorbed gas is in equilibrium with the liquefied adsorbent)
pressure) can be higher than 1 atm. this
In this case, the adsorbed material condenses at approximately atmospheric pressure. sample
The holder itself typically consists of two parts
be done. i.e. a relatively large volume to accommodate the sample.
and the capillary neck, which has a relatively small volume.
Ru. Approximately half of the capillary neck is immersed in the liquid bath.
while the rest of the capillary neck (at room temperature)
) is a part of the pipe section of the chamber when it comes into contact with the equipment.
becomes. The temperature of the chamber pipe section is the chamber pipe volume V_CT
approximately 98% of the time in a known constant temperature controlled environment (e.g.
(e.g. approximately 39°C).
therefore, the adsorbed material within this volume is controlled.
can be made equal to the ambient temperature, and therefore
It can also be made constant. Therefore V_CT
is a chamber conduit at a constant temperature in a controlled environment.
Represents volume. Then the volume V_CTPressure of adsorbent inside
Perform a force reading. Volume V_CTTemperature of adsorbent in
is the remaining 2% of the chamber volume that is at room temperature.
(V_RT) is in equilibrium with the adsorbed material present in
Assuming that. Therefore, room temperature fluctuations are compensated for.
and can be ignored. Therefore, V_CTand
V_RTThe temperature difference between V_CTcapacity
The product is the total pipe volume (V_CT+V_RT) sufficiently for
large, and the remaining chamber conduit volume is added to the total chamber volume.
It is sufficiently small in comparison, so this temperature difference is
can be ignored, V_CTThe temperature of
3 chamber pipe volume (V_L) temperature (T_L) is equal to
Ru. In this way, the outgassed sample is contained.
A known volume maintained at a known, substantially constant temperature.
A large evacuated chamber is provided. This room has good
preferably continuously, preferably at least as described below.
is sufficient to achieve an adsorbent partial pressure of 0.20.
and more preferably at least one of the adsorbed materials.
A portion of the water condenses on the adsorbent (i.e., the partial pressure becomes 1).
a known substantially constant mass for a sufficient period of time
The adsorbent is introduced at a flow rate, while the adsorbent is introduced into the room.
The amount of adsorbed material increases as a function of time during introduction of the agent.
Set pressure. In this specification, this pressure is defined as
It is called chamber pressure. The term “substantially” used in connection with mass flow rate
"Constant" is used during the entire period of gas introduction and
During virtually the entire period of gas withdrawal, the mass flow rate
The mass flow rate is not less than 0.2ml/min.
Even if a fluctuation occurs, the fluctuation is greater than ±0.4%.
no, preferably no greater than ±0.2%, and
most preferably no more than ±0.15%
used to define flow rate, and the term
“Substantially all gas removal period” or similar
The expression is the partial pressure range in which gas is extracted.
It is defined as described below in connection with. mass
When the flow rate is between about 0.05 and about 1.19ml/min
The term "substantially constant" means that the mass flow rate is
The mass may vary by no more than approximately ±1%.
is defined as the flow rate. Quality less than about 0.05
Quantity flow rate is not used in practice. This is because
so that a small mass flow rate completes the measurement cycle
Because it takes an economically unbearable amount of time to
It is. By using a substantially constant mass flow rate
As described later, the adsorbed material is introduced into the room.
Innes and
Conventional methods such as Bosch et al.'s capillary method
Measure with extreme precision never before possible
It is possible. The flow rate at which the adsorbent is introduced into the chamber depends on the sample.
From the equilibrium adsorption amount (rate or speed) of the adsorbed material
is selected so that it is not too large. More specifically
is suitable for any volume, temperature, pressure and contact with the sample.
Under the combination of the amount of adsorbed material, the amount of adsorbed material
The rate at which molecules collide with the sample and are adsorbed or
The amount of adsorbed adsorbent molecules from the surface of the sample is determined by
The amount produced will eventually be equal to the amount produced. This situation arises
Then, the adsorption amount or adsorption rate at that time will be at equilibrium.
It is called adsorption amount or rate. At constant volume and temperature, this equilibrium
Achievement of the condition may occur over a period of approximately 20 to 40 minutes, for example.
The pressure of the adsorbed material is constant (i.e. the fluctuation is ±
(not exceeding 0.25%). Main departure
The mass flow rate used in the
The introduction of the adsorbent is interrupted when the temperature exceeds
There is a finite period of time before the pressure in the room becomes constant.
It takes time. However, the mass flow rate is
of the adsorbent if not greater than the amount or rate.
If the supply is interrupted, the pressure will remain constant from the point of interruption.
Ru. Therefore, the mass flow rate should be larger than the equilibrium adsorption amount.
By controlling the
The pressure established at any point during the introduction of the agent is the equilibrium pressure.
It can be said that it is power. This is very true.
It is the meaning. This is because the adsorption isotherm is
Produces the amount of adsorbed adsorbent at equilibrium pressure.
This is because it can be obtained by This way
In this way, the adsorption isotherm can be easily determined. The above equilibrium flow restriction conditions can be satisfied.
The mass flow rate is proportional to the weight of the sample. moreover,
small surface area samples compared to large surface area samples.
Slightly higher mass flow rates can be used for
Let's come. This is because the equilibrium pressure is lower than in the former case.
This is because it is set quickly. Considering this point
at standard temperature for a sample weight of approximately 0.1 to 1.0 g.
Mass flow rate at temperature and pressure conditions (S.T.P.)
is not greater than about 0.7 ml/min, preferably 0.5
no greater than ml/min and most preferably
No more than about 0.4ml/min, typically about 0.05
to about 0.7 ml/min (e.g. 0.05 to 0.19), preferably
preferably from about 0.2 to about 0.5 ml/min, and most preferably from about 0.2 to about 0.5 ml/min.
Preferably, it fluctuates in the range of about 0.2 to about 0.4 ml/min.
obtain. The surface area and porosity of the sample are unknown.
0.5 ml/min, typically 0.2 to
Mass flow rates less than 0.4ml/min for most samples
It turned out to be appropriate. The flow mentioned above
The amount expressed as mass flow rate is the mass flow rate described later.
The controller controls the heat transfer of the gas, which is proportional to the mass of the gas.
This is because it responds to conductivity. Therefore, millili
Tutle (ml)/min is mass according to the Arrhenius formula.
can be converted to . As mentioned above, the adsorbent has a surface area measurement of
If the purpose is to
in the chamber for a sufficient time to achieve adhesive partial pressure.
It is preferable to introduce However, complete absorption
If a wear isotherm is desired, a value of at least 0.98
Adsorbent partial pressure is required. Partial pressure of adsorbent
(P/P_s) means, for example, at any time during the introduction of the adsorbent.
Let the chamber pressure (P) at a point in the free space of the chamber be
liquefaction of the adsorbed material (room temperature and volume).
pressure of the adsorbent (under conditions), i.e. the saturation pressure
(P_s) is the quotient divided by This partial pressure is
Also referred to as relative pressure. than 0.4
At high adsorbent partial pressures, the adsorption isotherm leads to
The linearity of the BET curve of Equation 5, which will be described later, gradually increases.
to be lost. Therefore, to find the surface area
When using the BET formula, typically around 0 or less
from about 0.4, preferably from about 0 to about 0.35, and
Particularly preferably adsorbent partial pressure of about 0 to about 0.30
It is best to use adsorption isotherm data over a range of
preferable. However, the difference in the adsorption isotherm
Other numbers to determine the surface area at even higher adsorption partial pressures
If a scientific model is available, these data
Of course, it would also be possible to use it. The method described here is
It is a method that can measure the amount of adsorbed material.
Therefore, the introduction of the adsorbent requires at least
The sample adsorbs at least a portion of the adsorbed material.
need to continue for a sufficient period of time. As mentioned above, the adsorbent is at least
Sufficient time for a portion of the adsorbent to condense on the sample
Most preferably, it is introduced into the chamber over a period of time. sample ho
Condensation, which is the liquefaction of the adsorbed material in the free space of the
Reduction should be distinguished from adsorption. Adsorption is adsorption
Occurs immediately after contact of the agent with the sample begins. Against this
Therefore, condensation occurs when the indoor atmosphere is absorbed in the presence of the sample.
This occurs as the adhesive begins to become saturated. I want to
The condensation is determined by the partial pressure of the adsorbent (P/P_s)=1.
For this reason, the introduction of the adsorbent until condensation occurs
Finalize the complete adsorption isotherm by continuing
It can be found exactly. Therefore, for the purpose of surface area measurement, it is necessary to
Achieves sufficient adsorption required to achieve even higher
In order to
is also large, preferably larger than about 0.2, and
most preferably greater than about 0.3 (e.g. 0.35
), and typically from about 0.2 to about
0.35, preferably about 0.25 to about 0.35, and most
The absorption range preferably ranges from 0.30 to about 0.35.
the adsorbent for a sufficient period of time to obtain the partial pressure of the adsorbent.
introduced indoors. To obtain a complete adsorption isotherm
The introduction of the adsorbent is typically from about 0.95
large, preferably larger than about 0.98, and
most preferably generates a partial pressure greater than 1.
continue for a sufficient period of time. Generally, as described herein
mass flow rate (actually, this mass flow rate will be explained later).
The temperature and pressure actually used should be
), and the partial pressure as above
is typically about 2 hours to 15 hours, preferably
from about 3 hours to about 12 hours and most preferably
When introducing the adsorbent for about 4 to 10 hours continuously
achieved between. The pressure in the chamber when the adsorbent is introduced is e.g.
as a function of time starting from the beginning of adsorbent introduction.
Detected by measuring the equilibrium pressure of the adsorbed material.
be done. Operate at a mass flow rate not greater than the equilibrium adsorption capacity.
During production, the sampling chamber pressure is equal to the absorption of the adsorbent.
Equal to the arrival equilibrium pressure. The equilibrium pressure of the adsorbed material is
Accurate part or all of the dressing isotherm is achieved.
Measurements should be made at sufficient times during the introduction period of the sea urchin adsorbent.
is preferable. Typically, this measurement
during the introduction of the agent from about 100 to about 10,000, preferably about
200 to about 2000, and most preferably about 300.
The process was performed to obtain approximately 600 pressure data points.
Now. Also, if desired, the adsorption equilibrium pressure of the adsorbed material
It is also possible to measure continuously. However,
However, the partial pressure of the adsorbent is in the range of about 0 to about 0.35.
Pressure sampling frequency of approximately 400 to 600 times
is the best choice for BET surface area measurements in adsorption mode.
was also found to be effective. The mass flow rate must be constant during adsorption of the adsorbent by the sample.
Before or after the sample adsorption cycle,
Preferably, it is determined at any previous point in time. this mass
The easiest way to determine the flow rate is a blank test.
It is to do. This blank test smell
is the same as that used when the sample is present.
The adsorbent is brought into the room in the absence of the sample under the following conditions:
the equilibrium pressure in the chamber, which is referred to as the reference pressure, over time.
Measure as a function. In this case, standard temperature and
The mass flow rate under pressure conditions can be determined from the following formula.
I can do it. MFR=273/760・△P/t(V_L/T_L+V_S.H./T_S.H.) ...(Formula 1) In the above formula, MFR is the quality in the blank test.
The flow rate is expressed in ml/min, and △P (mmHg) is the period
(t) represents the change in chamber pressure during temperature T_Lto
Chamber pipe volume in cm (cm³), V_S.H.is the temperature
T_S.H.Sample holder volume in cm (cm³),
T_Lis the volume V_Lrepresents the chamber pipe temperature (〓), and
T_S.H.is the volume V_S.H.At the temperature of the sample holder (〓)
Ru. The period (t) is usually the time of introduction of the adsorbed material into the chamber.
When the adsorbent is sufficient to condense in the room from the start
It is a period measured up to However, school
Pressure in blank test cycle for positive
The force/time relationship is essentially linear at constant flow.
Therefore, the time (t) is the pressure at which condensation of the adsorbent occurs.
Although it is possible to accurately extrapolate the pressure/time curve up to
As long as it is long enough. The mass flow rate is sampled in a blank test.
Using the same mass flow rate to find the chamber pressure/time relationship
of adsorbed sorbent once set using
Volume (V_ads) during the introduction of the adsorbent according to the following equation:
It can be calculated at any time (t). V_ads=273/760△P(V_L/T_L+V_S.H./T_S.H.) −△P′(V_L/T_L+V′_S.H./T′_S.H.) ...(Formula 2) In the above formula, P, V_L,T_L,V_S.H., and T_S.H.is formula 1
P′ is a parameter mentioned in connection with
Change in sampling chamber pressure during the same period (t) to
and V′_S.H.is the temperature T′_S.H.sample holder in
represents the sample holder volume corrected for the sample holder volume.
and T′_S.H.is the volume containing the sample V′_S.H.sample of
Indicates the temperature of the holder. very compared to the chamber volume
Use a small specimen holder volume, thereby
Eliminates the need to correct the holder volume and reduces the amount of adsorbed material.
Ignoring the period from the start of the introduction, equation 2 becomes
It can be rewritten as V_ads=273/760(V_L/T_L+V_S.H./T_S.H.)(P-P′)
(Formula 3) In the above formula, P is the standard pressure, and P' is the pressure of the adsorbent.
is the sampling chamber pressure after the feeding time (t), and
The remaining variables are the same as defined in Equation 1.
Other formulas such as those used by Bosch et al.
can also be derived. In this case, the sample
The characteristics of the case where there is and the case where there is no
Difference in time required to reach a certain adsorbent equilibrium pressure
Example of the amount of adsorbent adsorbed by the sample using
For example, calculate volume. However, in either case
Also, the amount, e.g. V_adsis the exposure in the presence of the sample.
The equilibrium pressure of the adsorbent, the mass flow rate and the adsorbent
Correlating the time required to reach equilibrium pressure
It is determined by In desorption, P′ is larger than P and the difference has a positive description.
Please note that numbers are added. Desorption mode is the opposite of adsorption mode.
In the desorption mode, the desorption medium or
or to measure the morphological characteristics of the sample.
solids to be desorbed as well as gases or substances to be desorbed
A liquid is used. The material to be desorbed is tested during desorption mode.
evaporated from the water. Therefore, it is in detachment mode.
In some cases, the starting material is first outgassed and then
The surface and pores of the
in contact with the desorbent, the pores are filled and the sample is
The outer surface of the material is at least a single layer of condensed material to be desorbed.
A sample covered with the agent is used. For convenience, try
to ensure complete filling of the pores of the sample.
Saturated with desorbent. exposed to gas that condenses on the sample.
It is called a desorption agent. Therefore, the term "desorbable agent"
is the model in which the gas or liquid that constitutes it is used.
instead of “adsorbent” to simply identify the
used for adsorption and desorption
The substances that make up the agents are the same. In implementing the desorption mode, known preferred methods are used.
is the constant volume and
The desorbent is condensed in a chamber with a temperature of
The sample is placed in a room atmosphere consisting of the gas phase desorbent.
Bring to equilibrium. This is typically
As described above, the adsorption mode is maintained until saturation of the sample occurs.
This is achieved through implementation. The adsorbent is
Here, preferably continuously, at least the sample is
for a period sufficient to desorb the compressed material to be desorbed.
More preferably, the desorbent is completely removed from the sample.
at a known, substantially constant mass flow rate until
Remove from chamber. Here, the term "substantially constant"
When used in conjunction with the desorbent mass flow rate, approximately
not less than 0.02, preferably less than about 0.03
0.04, particularly preferably less than about 0.04.
Partial pressure of desorbed material (P/P_s) is valid only in
Ru. For desorbent partial pressures less than about 0.02, the mass flow
The volume controller maintains the mass flow rate substantially constant.
I can't hold it. However, this means that the result
It does not affect accuracy. That is to say
Available devices in the partial pressure range 0.02 to 0.
This is because data cannot be obtained. The mass flow rate for extracting the desorbed material is (mass flow rate during adsorption)
Equilibrium desorption of the desorbed agent from the sample (in a similar manner to the amount)
It is controlled so that it does not become larger than the amount of wear. flat
Equivalent desorption amount or rate is the rate at which gas is introduced into the room.
Equilibrium under conditions where gas is removed from the chamber rather than being removed.
The equilibrium adsorption amount or
This has the same meaning as defined above regarding speed.
Using such a flow rate simplifies the procedure
be done. This is due to the optional
The chamber pressure at that point is the equilibrium pressure of the desorbed agent,
Plot the desorption isotherm with the data points on the upper axis.
This is because the equilibrium pressure of the desorbed agent is
Ru. With a sample weight of about 0.05 to about 1.0 g and S.T.P.
The desorption mass flow rate under conditions is typically about 0.7ml/
no more than about 0.5ml/min, preferably about 0.5ml/min
is also not large, and more preferably about 0.4
ml/min and typically about
0.05ml/min to about 0.7ml/min (e.g. 0.05 to about 0.7ml/min
0.19 and/or 0.2 to 0.7 ml/min), preferably
preferably about 0.2 to 0.4 ml/min, and more preferably
The rate varies from about 0.2 to about 0.3 ml/min. Samples with low porosity compared to samples with high porosity
A slightly higher desorption mass flow rate may be used for
can. The reason is that the equilibrium pressure is faster than in the former case.
This is because it occurs quickly. The porosity of the sample is unknown.
less than 0.5ml/min, typically
Desorption mass flow rate of 0.2 to 0.4 ml/min for many samples
suitable for As mentioned earlier, it is difficult to remove the desorbed material.
At the very least, it is possible to desorb the agent to be desorbed that has condensed from the pores of the sample.
continued for a sufficient period of time to In connection with this,
The above statement regarding the difference between condensation and adsorption is
This also applies to the detachment mode. That is, (in the sample
Complete removal of the desorbent from the surface of the sample (distinguished from pores)
Total desorption need not occur. The reason is that
The deposition isotherm mainly depends on the porosity characteristics of the sample.
It is. The condensed desorbent is removed from the sample pores.
By continuing to take out the material to be desorbed until the
Calculations regarding the remaining desorbed material adsorbed to the walls of
Through surgical correction, the hole size or hole diameter can be corrected.
Get the important information you need to find the fabric
Ru. As a matter of convenience, all desorbed materials are sampled.
It is desirable to remove it from Desorption of a desorbed agent condensed from a sample is typically
is the partial pressure of the desorbed agent (P/P_s)
occurs in This partial pressure of the desorbed material is equal to the partial pressure of the adsorbed material.
It is used with the same meaning as defined for
Therefore, the desorbed material is removed from the chamber, typically approximately
less than 0.20, preferably less than about 0.10.
most preferably less than about 0.04, and typically
Typical about 1.0 to about 0.2, preferably about 1.0 to about 0.2
about 0.1, and particularly preferably about 1.0 to about 0.02
It is sufficient to obtain the partial pressure of the desorbed material which can vary within the range of
removed from the chamber for a period of time. In general, as described below
Like, reflect the actual working temperature and pressure
At the desorbent mass flow rate converted as follows,
Such partial pressures typically last for about 8 to 20 hours.
time, preferably about 8 hours to about 16 hours, and
and particularly preferably for about 9 hours to about 14 hours continuously.
This is achieved in a short time for removing the desorbed material. As in adsorption mode, the chamber in the presence of sample
Pressure (referred to as sampling chamber pressure in desorption mode)
) is determined as a function of the time during which the material to be desorbed is taken out.
It will be done. This can be done, for example, when removing the desorbed material.
Starting from the start, when the desorbed material is removed
It is possible to measure the equilibrium pressure of the desorbed material as a function of the
This is achieved by Typically the equilibrium pressure of the desorbed material
The force is applied over a portion of the exact desorption isotherm, preferably over the entire
During the removal period of the desorbed material so that the body can be realized
Measured over a sufficient period of time. Do it like this
typically about 500 to about 40,000, preferably
or about 1,000 to about 10,000, and most preferably
approximately 1,000 to approximately 5,000 pressure data points are
obtained during removal of the desorbed material in the partial pressure range mentioned in
Ru. A pressure sampling frequency of approximately 2000 times is typical for pore sizes.
Suitable for most samples for distribution measurements
It turned out that. As in the adsorption mode, the desorption mass flow rate is
A blank test allows the desorption model to be tested in the presence of the sample.
Determined as appropriate before or after execution of the code. In other words, the empty sample holder is saturated with the condensed desorbent.
and then measure the chamber pressure, which is called the desorption reference pressure.
The same desorption material used during desorption mode
Desorbs the desorbent under various flow rate, temperature and volume conditions.
Take it out. The desorption mass flow is then determined according to Equation 1 above.
You can find the quantity. Calibration bracket for attachment/detachment
The pressure/time relationship in the rank test cycle is
Partial pressure after removal of the desorbent condensed on the sample holder wall
It is linear from the point to a partial pressure of about 0.02. I want to
Therefore, the time to take out the desorbed agent (time t in equation 1) is
Desorption labeling in which the contracted desorbent evaporates from the pores of the sample
the chamber pressure and preferably the desorption which results in complete desorption.
Blank test pressure/hour up to deposition chamber pressure
long enough to allow accurate extrapolation of curves between
It is enough just to be. Once the desorption mass flow rate is determined, this mass flow
Determine the desorption/sampling chamber pressure/time relationship using the amount
Then, according to Equation 2 or Equation 3 mentioned earlier,
The equilibrium pressure of the desorbed agent in the presence of the sample is
force, the mass flow rate of the desorbed material, and the equilibrium pressure of the desorbed material above.
By correlating the time required to reach the force
At any time (t) during the removal of the desorbed material,
The volume of the desorbed material (V_dsb) by calculating
You can ask for more. V obtained as above_adsor V_dsbmosquito
Then, find the adsorption isotherm and/or desorption isotherm.
You can For example, in the case of adsorption isotherm
is V on the Y axis_adsand the corresponding relative pressure on the X axis.
(P/P_s), (where P is the adsorption equilibrium pressure and P_steeth
is the saturation pressure of the adsorbent at room temperature),
V_adsThe curve can be plotted. On the other hand,
In the case of desorption isotherms, the relative pressure (P/P_s) included in
Instead of the adsorption equilibrium pressure (P), the corresponding desorption equilibrium
Use pressure. Using the information embodied in the adsorption isotherm
and calculate the surface area of the sample using the BET formula.
I can do it. In addition, the information embodied in the desorption isotherm
The pore size distribution is calculated from the Kelvin equation using
can be determined and total pores per gram of sample
Volume (V_p), the saturation pressure (V_s), molecules of the desorbed agent
Weight (M), molecular volume of desorbed agent (M_v) and liquid
Based on the density of the phase desorbent, the sample is
S.T.P. of adsorbed desorbent per gram of
It can be calculated from the total volume at
I can do it. BET table of a substance or material using the BET formula
You can find the area. This BET formula is
Typically, determine the internal BET surface area of a porous material
used in the relative pressure range of 0 to 0.35 to
It will be done. The linearized form of the BET equation is as follows
It is. Pr/V(1-Pr)=1/V_nC+C-1/V_nCPr ...(Formula 4) In the above formula, Pr is the relative pressure obtained from the adsorption isotherm
(P/P_s), and V is the test value at relative pressure Pr.
In the S.T.P. of adsorbed material adsorbed per gram of material
is the volume of V_nis the monolayer capacity of the adsorbent, i.e.
Expresses the volume of adsorbent adsorbed as a single layer on the sample.
I and C depend on the enthalpy of adsorption
It is a BET constant. If we plot the left side of equation 4 against Pr, we get a straight line.
can get. This line V_nThe slope and Y-intercept of
It can be calculated from the formula. V_n=1/slope+1/intercept...(Formula 5) Therefore, the BET specific surface area (SA_BET) is the following formula
It can be calculated from S.A._BET=V_n・N_av・S_npl/V_npl・W...(Formula 6) In the above formula, V_nis described by equation 4,
N_avis Avogatro's number and S_nplis the adsorbent molecule
is the cross-sectional area, V_nplis the amount of adsorbent in S.T.P.
is the cross-sectional area of the child, V_nplis adsorption in S.T.P.
is the molar gas volume of the agent and W is the weight of the sample. The adsorbent molecules within the monolayer closely approximate a hexagonal shape.
Assuming that the adsorbed molecules are
(S_npl) can be calculated from the following formula:
Wear. S_npl=1.091 [M/N_av)D]^2/3 ...(Formula 7) In the above formula, M is the molecular weight of the adsorbent, and N_avteeth
is the quantity already defined, and D is the density of the adsorbent.
degree. Kelbi to calculate the pore size distribution of porous materials
The equation is used. According to this equation,
The pore volume per square area per gram as shown in
One pore (or capillary) as a function of the ratio of products
The vapor pressure of the liquid contained within is obtained.
Ru. dv/ds=-V_L(σ_L)cosφ/(R)(T)(lnPr
)...(Formula 8) In the above formula, V_Lis the liquid phase desorbent in S.T.P.
is the molar volume of σ_Lis the desorbed agent when it is in the liquid phase
is the surface tension of , R is the gas constant, and T is the surface tension of
is the absolute temperature of the desorbent, and Pr is the relative temperature of the desorbed material.
is the pressure, and φ is the pressure between the liquid phase desorbent and the pore wall.
The contact angle between Assume all holes are circular and do not intersect
The following replacements are possible: dv/ds=1/2R_k ...(Formula 9) In the above formula, R_kis the Kelvin pore radius of the sample.
As those skilled in the art will appreciate, different holes may have different
Replacement may be necessary. Here, the liquid phase desorbent is
It is assumed that the entire surface is wetted within the tank. That is, φ
=0 and cosφ=1. This assumption
is advantageous for desorption from porous materials.
Ru. Therefore, equation 8 can be rewritten as the following equation
I can do it. lnPr=−(z)(V_L)(σ_L)/(R_k)(R)(
T)...(Formula 10) at a certain pressure interval to calculate the pore size distribution.
Volume of desorbed material (V_dsb), desorption isothermal
Find it from the line. The material to be desorbed is desorbed during this pressure section.
The radius of the hole is determined by the thickness (t′) from the Kelvin equation.
The desorbent remains adsorbed on the wall of the hole with
For the quantity, the formula R_p=R_kR according to +t′_kAfter correcting
It is calculated by Here T′ is Halsey
(Halsey). Detachment
By dividing the volume of the desorbed material by the difference in hole radius,
This gives the frequency in the pore size distribution curve. △V as Y axis_dsb／△R_pusing the value of and
R in angstroms on the X axis_pThe corresponding value of
Plot the distribution of pore diameter, i.e. radius (s), using
and below each peak in the plotted curve.
By integrating the area of
specific radius R_pFind the volume of the hole at.
relative to the amount of liquid phase desorbent adsorbed on the walls of the empty pores.
R to do_kFor corrections, please contact N.Y.Academie Press.
Adsorption, by Gregg and Sing, published by
Surface Area, and Porosity”
Ru. The pore volume per gram of sample is determined from the following formula:
Ru. V_p=(V_s)(M)/(M_v)(D′)……(Equation 1
1) In the above formula, the variable is a previously defined quantity. The present invention is embodied in adsorption or desorption isotherms.
limited to a specific mathematical model for using the information
I would like it to be understood that this is not something that can be done. This information is
Operate according to customary procedures or techniques if desired.
can be done. The method and apparatus according to the present invention also apply to chemisorption
It can also be used to do This chemical sorption
is useful for the following reasons. That is, (catalytic activity
Table of very small particles (such as particles with properties)
Can the surface and/or variance be determined?
It is et al. In addition, in this specification, such
The particles are referred to as the chemical sorbent or active phase. this
Particles are deposited on larger particles such as catalyst supports
In this specification, it is referred to as a supporting solid.
Ru. Dispersion of the active phase is very important in catalyst evaluation.
It is for use. The reason is that the contact on the surface of the support
This is because information regarding the number of medium areas can be obtained.
This field of analytical chemistry has made considerable progress, and
chemical sorbents suitable for use with certain active phases;
and for the proper selection of sorption temperature, e.g.
``J.Rev.Pure Appl, Chem.'' Vol. 19, p. 151
(1969) Muller's paper, “AICHE Symp.
Series”, Vol. 143, p. 143, 709-22 (1970).
Described in the paper by Farranto, R. In addition,
The contents of these papers are also incorporated herein by reference.
I am using it. What can be effectively determined using the chemisorption method?
The active phases that can be formed include Pt, Pd, Ni, Co, Cu, and Ag.
and Fe and Cr₂O₃, CuO, NiO, sulfide etc.
is included. For example, if the catalyst is platinum
Chemical sorbents suitable for
It is hydrogen that reacts with platinum. Therefore,
The temperature of the sorbent sample holder is at least the above temperature.
It is controlled so that Chemisorption mode is the activity present on the solid support.
A suitable chemical sorbent is added in association with the layer.
Adhesive is selective to the surface of the active phase rather than the solid support
carried out by selecting chemisorption to
be done. If you want to find the dispersion of the active phase,
Must know the weight percent of the active layer attached to the body
do not have. Adsorption mode is chemical sorption as adsorbent
using a solid-supported active material as a sample.
performed as described herein using Shungso
Ru. The temperature of the chamber should be adjusted accordingly to ensure chemical sorption.
Therefore, in relation to the chemical sorbent-active phase reaction threshold,
selected. At the completion of the adsorption cycle, the time
Physically and chemically adsorbed chemical as number
Determine the total amount of sorbent. During this adsorption cycle,
Chemical sorbents are chemically sorbed when the chamber is substantially evacuated.
The chemical sorbent no longer desorbs from the surface of the active phase.
Both physically and irreversibly chemically to a certain extent
It will be worn. In contrast, chemical sorbents
is only physically adsorbed by the supporting solid;
The complete desorption of the chemical sorbent from the body support is
This occurs during the subsequent evacuation. Furthermore, the active phase in the first adsorption cycle
Chemical sorption by the active phase follows the above evacuation.
Chemically inert on contact with chemically sorbed materials
effectively deactivates the reactive region of the active phase so that
become Upon completion of the first adsorption cycle, the chamber typically
to desorb the desorbable chemical sorbent.
Exhausted quickly. During this evacuation, perform pressure measurements.
No need to move, and pumping speed saves time
Selected to be done as soon as possible
be done. At the completion of evacuation, select adsorption mode.
is used immediately, typically in the first adsorption cycle.
the same chemical exposure at the same room temperature and mass flow rate.
Repeat for a second cycle using adhesive.
During this second adsorption cycle, the sample
Only physical adsorption occurs, and only occurs during the first adsorption cycle.
The adsorption of chemically adsorbed substances is reduced. this amount
is determined as a function of time, and the initial adsorption
cycle and the second adsorption cycle.
The difference in the amount of chemically adsorbed material is determined for the same period.
Melt. This difference is due to the chemical sorption by the active phase.
This is the amount of sorbent. Therefore, the % dispersion of the active phase on the solid support is expressed as follows:
You can track it down. % active phase dispersion=A/B×100 In the above formula, A is the chemical chemisorbed by the active phase.
is the number of atoms of the sorbent and B is the number of atoms on the solid support.
is the number of atoms in the active phase. Is the value of A the difference amount mentioned above?
and B is the weight of the active phase on the supporting solid.
Determined from the amount%. % active phase dispersion plus
The surface area of the sexual phase is irreversibly chemisorbed and
The amount of sorbent can be expressed as the corresponding molecule of the chemical sorbent (or
It can also be found by converting to atomic) numbers.
Ru. Therefore, the total surface area of the active phase is
Chemical sorbent molecules (atoms) chemically sorbed per child
The known relationship between the number and the area of each active phase metal atom
Find it from the relationship. of the apparatus used to carry out the method of the invention;
Preferred embodiments will now be described with reference to the accompanying drawings.
Ru. FIG. 1 shows a block diagram of the preferred elements constituting the device.
This is a Tsuku diagram. These elements include
A gas that acts as a source of adhesive or desorbent
Or gas supply section and chamber 10^-FiveDo not exceed mmHg
pressure, preferably 10^-7Pressure not exceeding mmHg
Especially preferably 10^-9To a pressure not exceeding mmHg
A vacuum or exhaust part that can be evacuated and a suction
Gases that are being absorbed or desorbed
The mass flow rate of the adsorbent and desorbent described later is
It can be controlled to a constant value as described later by the partial pressure of
A flow controller equipped with a mass flow controller
Volume control and typically about ±0.05mm of true pressure value
Measures the pressure of the adsorbent or desorbent with an accuracy within Hg.
Pressure sensing/recording unit that can measure and record
and the sample host of the sample and adsorbent or desorbent.
sample holder or removal from the sample holder.
volume and temperature as described below.
Adsorption or desorption section with a chamber that allows control of
and the above vacuum to assist in outgassing the sample.
or a gas discharge section using an exhaust section. Figure 2 shows a simplified diagram of the configuration of each of the above-mentioned parts of the device.
It is shown. Specifically, the gas supply section
are typically used for adsorption or chemisorption.
one with various different gases or gases
or two or more gas cylinders 101 to 10
It is equipped with 4. Each gas cylinder is
Exhaust solenoid valve (ASCOTM) 7 or 1 for
0 to conduit 211. these
The valve receives a signal from computer 117 at an appropriate time.
gas or air.
The body is configured to flow into the conduit 211.
is preferred. The pipe line 211 is connected to the exhaust solenoid valve 3
Mass flow through conduits 201 and 200 with
connected to the quantity control section. gas or gas
During introduction into the sample holder 109, the exhaust solenoid
The door valve 6 is closed, and gas is discharged from the pipe 211.
Via open valve 3, lines 200 and 201
into the mass flow controller. The mass flow controller of the device is also a mass flow controller.
or a controller. This mass flow rate
Controller has adjustable opening (aperture)
It is an electronic device that operates on the principle of
This mass flow controller can be used, for example, in calibration operations.
a certain substantially constant mass flow, such as the flow rate
Preset to send gas to conduit 202 at a certain amount.
(preset). However, this
Gas passes through the mass flow controller to the sample holder
109 or the holder.
Is it the fact that the gas is being extracted from
Therefore, there is no positive back pressure (during adsorption) inside the sample holder.
or negative back pressure (during desorption), which may cause quality
The flow rate is decreased relative to the preset value.
A mass flow controller continuously performs
Detects the actual flow rate and compares it with the preset value
However, if there is a deviation from the preset value, the opening or
Open and close the aperture until the above preset flow rate is reached.
Compensate by increasing or decreasing the flow rate until it is set again.
Make amends. caused by fluctuations in pressure within the sample holder
In addition to fluctuations in the flow rate, as will be explained later, the actual
must be controlled to achieve a constant mass flow rate.
There are other factors that must be considered. For example, mass flow rates in adsorption and chemisorption modes
In order to use the controller successfully, the flow control
The gas supply to the controller is at virtually constant pressure.
should be maintained. The reason is that this kind of mass
The flow controller controls changes in inlet gas pressure
Or one that corrects fluctuations relatively slowly.
This is because. Here practically constant pressure
is the pressure of the gas entering the mass flow controller.
If there is a deviation or deviation in force, the deviation
but about ±0.35psi, preferably about ±0.30psi, and
Particularly preferably means a deviation not exceeding ±0.20psi.
Defined as Pressure fluctuations will be discussed further below.
By using a narrow tube in the manifold to
will be reduced by more. For adsorption mode, the mass flow
The pressure of the adsorbed material supplied to the quantity controller is
Typically about 15 to about 25 psig, preferably about
Controlled at 16 to 18 psig. More importantly, conventional mass flow control
Flowmeters used successfully in
transmitted to or flowing gas
extracted from the gas and changes in the gas flow rate.
induced at different points in the gas flow by
The temperature difference affects the conductivity of the sensor and the gas flow rate.
cause a change in proportion to a change or change in
It operates on the principle that
It is a point. Changes in the temperature of the gas as it enters the flow meter
In particular, each unit °C variation in the temperature of the adsorbent
Operates under the conditions described below at a mass flow rate of approximately 1.5%.
If the heat sensing mechanism of such a flow meter
It is found that an error or error is caused.
There is. This error or error may occur over a long period of time.
This will greatly affect the accuracy of the flow rate you are trying to find.
to the extent that it has an impact. In addition, the adsorption described later
and the ambient temperature used in desorption (e.g. room temperature)
The flowmeter's thermal response detection mechanism also detects long-term fluctuations in
and disturbances in the electronic circuit of the flow controller
due to the mass flow rate for the preset value of flow rate.
It has also been found that this results in a fairly large cumulative error.
ing. When the above-mentioned errors are combined, the present invention
under all conditions under which the method is practiced.
Virtually constant mass using volume flow controllers
It becomes impossible to achieve a flow rate. Therefore, achieving a substantially constant mass flow rate
A mass flow controller capable of
Ru. Preferred embodiment of this mass flow controller
are collectively shown in Figures 3 and 4.
Ru. Also shown in FIG. 2 is a mass flow controller 30.
The incorporation or integration of No. 1 into the device of the present invention is shown in FIG.
It is understood. Referring to Figure 3, the pressure control device or
With the exception of force controller 311, the mass flow controller
The components of the controller are temperature-controlled boxes or bottles.
It is housed in a box 119. This box or
The box has an internal space 608, which
The internal space is connected to the atmosphere through a vent 601 outside the box.
fluidly coupled, so typically air
It's full. This box is typically made of sheet material
Made from sturdy materials such as
has a volume of approximately 2500 c.c. The temperature of the atmosphere inside the box can be controlled by active control of the box temperature.
to enable and thereby maintain the temperature constant
In general, it is preferably maintained above ambient room temperature.
Typically, this temperature is contained within a box.
to avoid damage to the electronic system inside the box and the box.
Provide a sufficient temperature gradient between the external atmosphere to
The air in the room is drawn from outside the box by the fan 407.
Dynamic temperature equilibrium is achieved within the box when it is drawn into the box.
at temperatures between approximately 35°C and 45°C (e.g.
The temperature is maintained at 39°C. Therefore, the selected
The box temperature that is
Emitted by the electronic system of the flow controller
to a temperature above that which the box reaches due to heat.
It is advantageous to Therefore, the external environment of the box?
The air from the box is mixed with the air inside the box and heated.
The temperature equilibrium achieved within the box is controlled by the mass flow controller.
It is not disturbed by the electronic system. The temperature inside the box is controlled by the flow controller block.
Thermistor 404 attached to the base of 403
and proportional-integral-derivative (hereinafter referred to as PID) controller
405, heating strip 406, and fan 4.
This can be achieved in combination with 07. thermistor
404 can be used inside the box over a temperature range of 0 to 100°C.
Detects the air temperature and generates an electrical signal proportional to it.
This signal is sent to the PID controller 405.
Supplied. The PID controller (RFL model 7
0A) is the preset box temperature
and the actual box temperature.
It is preset to occur. PID control
An electrical signal generated by a roller (e.g. resistive type)
300W capacity) heating strip 406 is activated.
Ru. Therefore, the heating stress from the PID controller is
The magnitude of the electrical signal applied to the lip is the actual
gradually as the box temperature approaches the preset temperature.
and the actual box temperature relative to the environment
The temperature is equal to the preset temperature by compensating for heat loss.
Sometimes the signal is substantially constant. This way
In this way extremely accurate temperature control is achieved. centre
Ann 407 is connected during operation of the mass flow controller.
Operating continuously, about 10 to 100 of the box volume per minute
higher flow rates (e.g. 10 to 75 times) or higher
The air inside the box is circulated around the heating strip at a higher flow rate.
circulates. Juan 407, fresh air box 1
19 Air vent or vent 6 to draw air into the air
It is preferable to arrange it near 01. The temperature control in box 119 has at least four important
fulfill a function. That is, (1) heating the gas flowing into the pipe line 201;
Then, the gas reaches the detection coil 411 of the flowmeter.
By this point, the gas is in the boiling water regardless of room temperature fluctuations.
The temperature will be the same as that of Tux 119. (2)
Electronic circuit provided on circuit board 401, thermal response
Valve 302 and pressure transducer or transducer
temperature sensing of sensor 108 (described below).
(3) The temperature of the gas in the pipe line 210 is
becomes constant at the location measured by sensor 108
This is guaranteed. (4) As shown in Figure 2, Box 1
For the gas in the chamber pipe space contained in 19
The effects of changes in ambient temperature are removed. Moshiko
If temperature control such as
Errors occur in the pressure measurement of the gas in these pipes.
obtain. In order to support the realization of functions (1) and (3) above,
For this purpose, conduit 201 is arranged to form coil 213.
and the conduit 210 is adapted to the coil 2
12. of the coil
The volume (i.e. the internal passage volume of the coil) is
13, with 0.5c.c. and the field of coil 212.
In this case, it is appropriate to set it to 0.8c.c.
Then, temperature equilibrium between the gas inside the coil and the box temperature will be achieved.
Can be done. The mass flow controller itself is shown in Figure 2.
301. mass flow controller
An inlet of 301 is connected to conduit 201.
This conduit 201 has a flow to the mass flow controller.
The purpose of maintaining the pressure of the incoming gas substantially constant
and a pressure controller 31 in series with the controller.
1 (SERTATM model 204) is provided.
There is. The outlet of the mass flow controller is connected to line 20
Connected to 2. Mass flow controller 30
1 is shown in more detail in FIGS. 3 and 4.
There is. Referring to Figure 3, the mass flow controller
The primary side elements of R include the following: Immediately
(A) Detection conduit 201a and detection coil 411
and a heat disposed downstream of the detection coil 411.
Controllable aperture or opening of response valve 302
The sensing conduit 201a is a thermally responsive valve.
302 and extends the entire length to connect with
stainless steel block 403 and (B) detection blitz.
circuit 408, linearization circuit 409, and amplifier 4
10 and a comparison controller circuit 600.
Circuit board 401 with the electronic circuit of the quantity controller
and (C) a thermally responsive valve or thermal valve 302.
Ru. Although the pressure controller 311 is necessary,
However, as an auxiliary element of a mass flow controller,
Please note one point. Introducing and removing gas to the detection conduit 201a
The output is via conduits 201 and 202, respectively.
will be carried out. The detection conduit 201a is connected to the block 403.
starting from the inlet of the sensor coil 411 (see Fig. 2).
is shown as a single coil, but specifically
consists of two separate coils as shown in Figure 3.
) and connects to the inlet portion of the thermally responsive valve 302.
It is continued. Thermal response valve or thermal valve 30
The outlet part of 2 is connected to the pipe line 202,
Gas can leave block 403 via the conduit.
can. The main body and electronic circuit of the thermal valve are
It is screwed onto the top of block 403 and is made of plastic.
It is enclosed within a housing 412 of the type. A preferred thermally responsive or thermal valve is
Commercially available from Teylan Corporation
and as described in U.S. Pat. No. 3,650,505.
Described in detail. Please note that this U.S. patent
The content herein is incorporated by reference.
Ru. The circuit board 401 is a plastic housing 4.
It is included in 02. Next, the circuit and operation of the mass flow controller
will be explained with reference to FIG. Broken line 51 in Figure 4
In the block shown by 6, there is a detection conduit 201a.
Flow control including coupled bridge circuit 517
The flow meter portion of the roller is shown. Bridge times
The bridge is of conventional design and the first bridge
Resistor 501 and second bridge resistor 502 etc.
It is formed from Furthermore, the bridge circuit is
Side sensor element 411a and downstream sensor element 411
It is equipped with b. These sensor elements 411a and
and 411b are adjacent to each other and connect sensing conduit 201a.
wrapped around the upstream sensor element.
411a approaches the inlet end 518 of tube 201a;
The downstream sensor element 411b is the outlet of the conduit 202.
It is located close to the end 519. Bridge circuit 517 also provides DC power and
converter 506 (this circuit operates on AC power 507)
). One side of the bridge circuit is a railway line.
604 of sensor elements 411a and 411b.
connection point and the other side of the power supply is
bridge resistors 501 and 502 through the bridge 505
connected to the connection point. from bridge circuit
The output signal is output from the first output terminal 503 and the second output terminal.
power terminal 504 . First output terminal 50
3 is the upstream sensor element 411a and the first bridge.
connected to the connection point with the Tsuji resistor 501, and
The second output terminal 504 is connected to the downstream sensor element 41
1b and the second bridge resistor 502.
It is connected. The upstream sensor element 411a
and the downstream sensor element 411b are connected to the conduit 201
Is the temperature sensing resistance wire wrapped around the outer diameter of a?
It is formed from Such a resistance line is
For example, Balco (manufactured by Wilbur-Driver Company)
It can be an iron-nickel alloy such as
Ru. The circuit design described above is conventional with the following exceptions:
It is. That is, the inner diameter of the sensing conduit 201a is
approximately 0.2mm, preferably 0.05mm and most preferably
Preferably not more than about 0.02mm and not more than about 0.005
about 0.2 mm, preferably about 0.01 to about 0.1 mm,
and most preferably within the range of about 0.01 to 0.05 mm.
of the size of a capillary, thereby making parenchyma
Traditionally, it achieves a constant flow rate.
It can be of any design. In addition, the flow meter
Since the flow rate processed by is a low pressure flow rate, this type
Bypass line commonly used in mass flow meters
should be omitted. In addition, the detection conduit 201a
If the inner diameter is made excessively large, the
gas tightness in the pipe at the pressure and flow rate
The thermal conductivity of the gas decreases.
The heat detection mechanism of the flowmeter (described later) may be disturbed.
as a result of which a virtually constant flow rate is achieved.
It turned out that it was not possible. The combined bridge circuit output signal 503 and
504 is connected to a linearization circuit 409. this
Linearization circuit 409 electronically calculates the function of mass flow rate and
to generate a linear output voltage. This voltage is the amplifier
applied to comparison controller 600 via 410
It will be done. Note that the linearization circuit, amplifier, and comparator
All troller circuits are conventional. In operation, closing switch 505 turns off the power.
flow through sensor elements 411a and 411b;
The sensor element generates heat so that the sensor
The temperature of the tube 201a adjacent to the element increases. Ma
Additionally, the addition of these sensor elements 411a and 411b
Heat also increases their resistance. Conduit 201a
When the fluid flow rate is zero at
The temperatures of elements 411a and 411b are equal to each other.
The bridge is in equilibrium and terminals 503 and
A zero output voltage is generated between and 504. The fluid is
Upon entering input end 518 of tube 201a, element 4
The heat generated by 11a and 411b is
downstream by the body toward the outlet end 519 of tube 201a.
transported to the side. Therefore, along the pipe 201a
element 411a due to the transition in the temperature profile.
A temperature difference occurs between and 411b. tube 201
As the fluid flow rate in a increases, the upstream
The temperature of element 411a and its resistance value decrease,
On the other hand, at the same time, if the temperature of the downstream element 411b is
Its resistance value increases each time. Therefore, terminal 5
The bridge output voltage between 03 and 504 depends on the flow rate.
increases in approximately linear proportions. Terminal 503 and
and linearization of the bridge output voltage appearing at 504.
After the gas is thermally
The absolute value of the mass flow rate of gas before reaching valve 302
generates a linear voltage corresponding to Amplifier 410?
These voltages are applied to the comparison controller circuit 600.
where the command source as well as the selected mass
The selector is preset to correspond to the flow rate.
Comparison with external electrical command signal 514 from controller 520
be done. The comparison controller circuit uses the command signal voltage
and the amplifier output voltage, the difference output signal
This difference output signal is transmitted via line 603.
The actuator 302a of the thermal valve 302
It is used to energize. controlled like this
The thermal valve actuator is controlled by the comparison control circuit 6.
00 is insufficient for the mass flow to balance the command signal.
When indicated, the thermal valve is opened.
and vice versa, close the thermal valve. A command signal is selected using selector 520.
At times, the selector 520 also
and transmits the digital signal to the computer 11 in FIG.
Send to 7. This digital signal is selected and
Calibrated with a previously performed blank test cycle.
This is a signal representing the flow rate. In yet another preferred embodiment, the sensor element
Elements 411a and 411b are described in U.S. Pat.
As disclosed in US Pat. No. 3,938,384,
Can be combined into a single coil with taps
Wear. Please note that the disclosure content of the above US patent specification is for reference only.
is incorporated herein by reference. two separate cells
Instead of a sensor element, a single component with a center tap
By using coils, the coils can be placed closely together.
can be used, thereby reducing heat loss and
Equalization between upstream and downstream sensor elements
circuit gain (per unit flow rate).
temperature change) increases. Furthermore, the response of the circuit is
Fast and useful flow measurement range and times
The linearity of the path increases. As an optional feature of the circuit shown in Figure 4, the
Connect a voltmeter between the combined output terminals 503 and 504.
510 can be provided. from this voltmeter
The electrical signal is converted to analog by a converter (not shown).
form is converted into a digital BCD signal, and then
The BCD signal of the lever is transmitted through the line 303 as shown in Fig. 2.
It is sent to computer 117. Bulk for calibration
During the rank test cycle, the computer runs approximately 10
Sample the output from voltmeter 510 over a period of
Ru. During this period, the computer outputs one data point per second.
Capture data at a rate of
The resulting data is calibrated
is stored in the database as a value. Adsorption and
During installation and removal operations, the computer uses the above calibration values and
Compare with the actual value sampled from the voltmeter,
Determine whether the operation is being performed reliably.
Ru. This operation is performed from the desired flow rate after the operation is completed.
With a quality control function that allows you to read the deviation of
be. Above is a mass flow controller associated with a particular flow meter.
Although we have described the troller, for example, U.S. Patent No.
Described in No. 3650151, No. 4056975, No. 4100801, etc.
Generates an electrical signal vs. flow function as shown in
Other types of flow meters can be used and
I want to be understood. Also, the thermal valve mentioned above or
It is preferable to adjust the flow rate with a heat-responsive valve.
However, under the conditions of use described herein,
ability to control the flow rate at a constant level and
Other electrically actuated means with
I can be there. The same goes for mass flow control.
The same can be said about the rollers themselves. In carrying out the present invention
for long periods of time as described herein.
over a range of low flow and low pressure conditions.
The ability to achieve a substantially constant flow rate is required.
Ru. The person who developed the device with this ability was
We believe that the inventors are the first, but
The methods and apparatus of the present invention may be developed in the future.
of mass flow controllers and associated environmental control boxes.
exclude the use of alternative means that can perform the required function.
It's not something you can do. Referring again to FIG. 2, inside the environment control box 119
Gas flowing through the conduit 201 disposed in
passes through coil 213, where the temperature of the gas is
to equilibrate with the temperature in box 119, then the flow controller
301, where the flow rate of the gas is already
The pipes 208, 209 and the exhaust are adjusted as described above.
Air solenoid valves 4 and 5 and stopcock 19
The water flows into the sample holder 109 of the sample holder section through the
Ru. The sample holder section includes a sample holder 109 and a liquid bath.
Container 111 and liquid level controller (control device)
(113, 20) and a liquid bath 112. trial
The material holder 109 typically has an inner diameter of about 2 mm.
A capillary neck 122 made of glass and a volume of 20 ml.
It is a glass flask. The capillary neck 122 is a tube
125 polished male glass fitting or
Suriga adapted to receive joint 124
It terminates at the last joint 123. Sample holder 1
Added sample or sample 110 to 09
or remove it from the holder.
Las joints 123 and 124 are separated.
Ru. Glass joint 124 connects to stopcock 19
The conduit 125 was connected to the conduit 19.
Conduit 126 and associated ground glass joint
An assembly or assembly containing 127 (hereinafter referred to as
For example, the assembly A) may be
The sample holder 109 is degassed at the joint 21.
or using a glass joint 128, for example.
A mass flow controller section is installed at the end of the conduit 209.
Used for sealing and/or connecting.
For example, assembly A includes gas release and exhaust
After that, the sample is removed by closing the stopper 19.
This allows the sample holder to be sealed tightly.
In this way, assembly A and sample holder 1
09 seals the sample holder 109 and stores it inside the device.
It allows you to move to the desired location.
Ru. The liquid bath container 111 typically contains a liquid such as liquid nitrogen.
Dewarf flask capable of holding a liquid bath
(Thermos flask) with mass flow rate control.
Immersion of the sample holder 119 when connected to the control
It is of sufficient size to allow for. Already
As mentioned above, the liquid bath 112 typically
liquid to be adsorbed or desorbed, level 1 of bath 112
29 is constant in the liquid bath container 111 during adsorption or desorption.
If the bath 112 is maintained at
It functions to control the temperature of the sample holder 109.
Also, the bath 1 with respect to the immersion depth of the sample holder 109
12 levels 129 in equations 1, 2 and 3.
The volume of the sample holder V_S.H.on the other hand, bath 11
2 is the temperature T in these equations_S.H.and
(or) T′_S.H.stipulates. For example, container 111
The bath level 129 in the container 112 is at the capillary level described above.
Test at a point or location 130 in the canal neck 122.
so as to intersect with the capillary neck 122 of the material holder 109.
The bath 112 is filled with enough water. position of point 130
Typically, the ground glass joint 123 and
Capillary neck of sample holder 109 at point 132
midway between the end of the Inside the container 111,
The sample holder is stabilized and the bath level 129 is
When the sample holder 109
are immersed to the same depth in bath 112.
A sample holder rack 131 is provided to
There is. Therefore, V_S.H.is immersed in bath 112.
The volume of sample holder 109 that is
109 points 130 to 132 of the capillary neck
It is equal to the sum of the volume plus the volume of the remaining non-capillary part.
stomach. The level 129 of the bath 112 in the container 111 is
Sensor 113 adapted for use in embodiments
control valve 20 and bath level sensor operated by
collectively shown as 113
"Model 200" by Hungtington Electronics Inc.
at a constant level using a conventional liquid level control device such as
Retained. For example, using liquid nitrogen as a liquid bath.
liquid nitrogen has a tendency to evaporate during the experimental process.
direction. Therefore, the bath level remains virtually constant.
Additional liquid nitrogen must be added to maintain
Must be. For this purpose the bath level sensor 113
detects a change in bath level and activates control valve 20.
and add fresh liquid nitrogen to lines 308 and 310.
Let it flow. However, this liquid nitrogen
When flowing into 308 and 310, the temperature of the pipe is
The temperature is higher than that of liquid nitrogen, which makes the nitrogen
evaporates explosively. Therefore, liquid nitrogen and
Vaporized nitrogen typically flows violently into the liquid bath 112.
By being released, thereby bath level 12
9 is disturbed. This result is recorded as a function of time.
An error or error occurs in the applied pressure. this
The problem is that before the fresh bath liquid flows into the liquid bath container,
Venting for separation of fresh bath vapor from fresh bath liquid
Alternatively, it can be implemented by providing a vent pipe 309.
It has been found that the problem can be solved effectively and completely. This person
According to the law, the liquid level is within ±0.5mm deviation of the bath level.
Once the bath 112 has evaporated, the control valve 20 controls the liquid bath source.
(not shown) from conduit 107 connected to
Receive fresh liquid. The bath liquid flows from the control valve 20 to the pipe line 30
8 and flows into conduit 310. Opening of the conduit 310
The end is immersed in a liquid bath 112. Conduit 309
are open to the atmosphere and in fluid communication with conduits 308 and 310.
It constitutes a vent that communicates with the body. Conduit 310
The end is inserted with a glass wool plug,
As a result, back pressure is created and the vaporized liquid is
venting rather than being violently discharged into the liquid bath 112
It flows out via line 309. In this way,
Severe fluctuations in the bath level 129 are avoided and the bath level
remains substantially constant. bath level 129
By keeping T substantially constant, the temperature T_S.H.
volume V at_S.H.is also held substantially constant. In this way, to control the temperature of the indoor pipe space
In this case, use box 119 and in combination with the sample ho
Using a liquid bath to control the temperature of the chamber
Due to the total room volume and accommodated within it
A gas or gas is maintained at a substantially constant temperature.
It will be done. Terminology used here regarding total room volume
"Substantially constant temperature" means the average temperature of the entire room volume.
Typically, the average temperature value
not exceeding ±0.35%, preferably not exceeding 0.20% of
and even more preferably not to exceed 0.17%.
means. Main components of the pressure sensing and recording section of the device
includes a pressure transducer or transducer 10
8 (SETRATM 204 300A) and computer
Pressure recording device such as Ta117 (Apple IITM)
and/or the strip paper recording device 118 is
included. The pressure transducer 108 is connected to the environment control box 11
9, the inlet end of which is connected to the conduit 21.
0 and through coil 212 (exhaust solenoid valve
4 and 5) connected to conduit 208
The coil 212 is also connected to the environment control box 119.
It is located inside. Conduit 208 is connected to adsorption and
It is placed in fluid communication with the sample holder during desorption. Ko
In box 212, the gas in line 210 is transferred to box 119.
heated to equilibrium temperature. Therefore, conduit 208
A certain amount of gas flowing through conduit 210 and the coil
212 to contact the inlet end of pressure transducer 108
do. The temperature of the gas in the coil 212, that is, the temperature of the box
The degree is therefore constant and the pressure change in the line 210
is surely caused by a pressure change inside the sample holder 109.
reflect. Pressure transducer 108 operates at a constant temperature.
The pressure inside the conduit 210 is sensed, and the sensed pressure is
Converts the force into an electrical signal, and the electrical signal is transmitted to a pressure transducer.
From the output end of 108, the interaction is made via line 304.
A/D converter 121 (model A003-4)
is applied to the input terminal of This A/D converter 121
converts the analog electrical signal from pressure transducer 108 into
Convert to digital electrical signal. This digital
The signal is transmitted from the output end of the A/D converter 121 to the line 3.
06 to the digital computer 117.
be provided. The analog output signal from pressure transducer 108 is
The strip paper recorder 11 is connected via the output line 305.
8 can be supplied. Computer 117 and strip paper record
sample holder 118 as a function of time.
9 or being removed from the holder 109.
is an alternative means of recording the pressure of a gas.
Therefore, each can be used independently.
It can also be used in combination. But long
However, it is preferable to use a computer. In the adsorption mode, the computer 117
It is programmed to perform operations such as:
(a) the pressure transducer or transducer as a function of time;
Digital pressure received directly from the sensor 108
Force signals are typically recorded on a quasi-continuous basis to measure pressure.
Setting up and storing a first database of time
and (b) the computer out of several different mass flow rates.
of the mass flow rate selected by the controller operator.
(c) determining and storing a second database;
The pressure versus time information of the first database and the second
The selected mass flow rate in the database of
The wear isotherm, i.e. V_adsPair (P/P_s) or part thereof
Convert the third database into a third database
(d) storing the third database;
For example, try using the BET formula from the information in the database.
The purpose is to calculate the surface area of the material. In the detachment mode, the command
The computer 117 is connected to the suction mode.
Define and rank the first and second databases mentioned above.
be programmed to deliver. Then compile
data is the desorption isotherm, i.e. V_dsbPair (P/P_s) No.
3. Confirm and store the database, and use this third database.
Using a database, using the Kelvin formula, etc.
Calculate the pore size distribution of the sample using Equation 11.
Calculate the total pore volume. The first database of pressure vs. time mentioned above is
To determine, the computer can adsorb or desorb
Samples digital pressure signals on a quasi-continuous basis during operation
Convert and store. The sampling frequency in this case is
controlled by the controller. Specific laps selected
The wave number will be discussed later. The second database of mass flow rates mentioned above
command voltage source/selector 52
0 is about 12 different tests using blank test results.
calibrated with the same voltage setting, and each blank
Determine the actual mass flow rate for each strike. A typical one
The 12 flow rates used as S.T.P. (standard temperature and
and pressure) varies from approximately 0.2 to approximately 0.7 ml/min.
do. The computer was calibrated there
Flow rate and each command voltage and related digital voltage
programmed with Therefore, for one operation, the operator
Selecting one of the calibrated command voltage settings,
Command voltage selector 520 automatically selects
A corresponding digital signal representing the flow rate is connected to line 132.
The data is sent to the computer 117 via the host computer 117. computer 1
17 uses this information to perform adsorption as described later.
or used to calculate the amount of gas desorbed.
Determine the desired mass flow rate. This kind of behavior can be done automatically.
A computer's ability to dynamically execute virtually
made possible by using a constant mass flow rate
This is one advantage. The computer also fully automates the system
performs some additional functions that serve to
Ru. That is, the computer controls many functional elements of the device.
Manipulate. These operations require gas from the gas supply.
Solenoid valve opening/closing for sample holder selection
Introducing or removing gas to or from the da 109, gas
For evacuation and desorption processes of sample holders during release
Sample preparation with condensed gas as a preliminary operation for
Includes saturation. Computers also
Control outgassing conditions such as duration. The exhaust section is depressurized to release gas from the sample.
Evacuate the sample holder and remove the desorbed material from the desorption medium.
Attach and detach. The exhaust section includes a vacuum pump 105 and
Pressure gauge 120 (Edward CP25 Gaugehead)
Mechanical discrete vacuum pumps collectively indicated as
It is equipped with a Mechanical pump (Varian O401
-K6820-301), the pressure inside the pipe line 204 is 10^-3
mmHg, on the other hand placed in series with the mechanical pump
Diffusion pump (Varian O160−82906−)
301) is the pressure 10^-7or 10^-8Desired level of mmHg
decreases to le. Pressure gauge 120 indicates that the vacuum pump is functioning properly.
Conduit 20 to check whether
Read the pressure directly from 4. vacuum pump 105
The low pressure side end is connected to conduits 205 and 203.
It is connected to the device via a conduit 204 that is connected to the device.
Open and close exhaust solenoid valves 1 and 2 appropriately.
Due to this, gas release and adsorption/desorption parts are alternately
is connected to a vacuum pump 105. The gas release part is an aluminum heating block.
14 and one or more conventional cartridges
J-type heater 115 and exhaust solenoid needle valve
11 and supplying current to the cartridge type heater.
It is equipped with an AC power supply 16 for this purpose. aluminum
The block is adapted to accommodate the sample holder 109'.
ground to have a space 114 adapted to
ing. One space 114 and one sample holder 1
Although only 09' is shown, aluminum block
The tool 14 typically receives four sample holders.
It is adapted to be heated and heated.
Ru. Ground glass joint 127', capillary channel 1
26', stopcock 19', capillary channel 125' and
Consists of a ground glass joint 124'
In assembly A, the sample holder 109' is
glass joint 21, electrically actuated exhaust
Via the air valve solenoid 11 and the conduit 206,
It can be connected to an exhaust section or a vacuum section.
To attach the sample to the sample holder 109',
Separate assembly A, and remove sample 110' from sample 110'.
holder 109', and assembly A
Reconnect as shown. A vacuum pump 10 is used to degas the sample.
5, open the stopcock 19' and close the solenoid.
Close valve 1, open exhaust solenoid valve 2, and
First, open the exhaust solenoid valve 11 intermittently and test it.
The sample 110' is separated from the sample holder by suction.
Make sure not to. Next, throw in a cartridge type heater.
and under low pressure until outgassing takes place.
Heat the sample. Next, close the stopper 19',
On the other hand, the sample holder is kept under reduced pressure or vacuum.
However, while maintaining the sample 110' in an evacuated state,
and transferred to the adsorption/desorption section. So the solenoid
Close the handle valve 11 and close the sample holder 109'.
The assembly A connected to the ground glass
Separate from joint 21. Sample holder/attachment
The combination of assembly A is cooled and then as already mentioned.
Connect to the adsorption/desorption section. All gas conduits shown in Figure 2 are
up to the metal glass connectors 135 and 136.
0.05 to 0.2 inch inner diameter stainless steel
It consists of a core tube. all glass gas
The conduit has an inner diameter of about 2 to 6 mm and an outer diameter of about 7 mm.
It is a 12mm capillary channel. Also, valve 1 and valve 1
All solenoid valves except 1 are conventional electrical
Exhaust valve operated by Hardman-VA-250-
AE1-2-10-21), and valve 1 is an air-operated valve.
(ASCO^TM), and the valve 11 is electrically actuated.
Driven Needle Valve (Whitey^TM). valve 4
and 2 is a reversing valve that works in only one direction.
be. Pressure is applied to the low pressure side of these valves 4 and 2.
These valves then act as check valves. all metals
Joints are welded wherever possible. For adsorption mode, the formula must be known
1, 2 and 3 V_LThe pipe volume expressed as
Roads 202, 208, 209, 126, 125 and
and 122 and conduit 210 and coil 212
between point 130 on conduit 122 containing valve 302 and valve 302.
is the volume defined by In the desorption mode, valve 4 is closed and
Then, starting from valve 302, the existing equations 1, 2 and 3 are
Knowledge V_LA circuit with pipe volume expressed as
Ile 213, pipe line 201, 207, 208, 20
9, 126, 125 and 122, conduit 12
2 to point 130 and the conduit 210 and
It is determined by the volume of the coil 212. Typical volumes are as follows. Valve 1
8 to the sample holder 109, and
The volume including the sample holder 109 is approximately 20ml, and the valve 19
The volume from the mass flow controller 301 to the mass flow controller 301 is approximately 19
ml, from the outlet of box 119 in conduit 209 to conduit
The volume up to point 130 on 122 is about 0.6 to 0.8
ml, conduits 201 and 207 including coil 213
has a volume of approximately 4 ml, and the conduit 210 and coil
The volume of 212 is approximately 7.5ml. Therefore, the
As is clear from Figure 2, the pipes 201, 202,
208, 210 and 207 placed in box 119
This is very important for pressure measurement.
Only a very small portion of the pipe volume remains at room temperature and beyond.
It is not subject to fluctuations related to this. Therefore, this
The effects of such fluctuations are reduced to a negligible degree.
Ru. Therefore, the chamber below bath level 129
Box 119 contains approximately the volume of the chamber pipe.
94 to about 99%, preferably about 96 to about 98%
Preferably maintained. Degassing is completed at the beginning of the adsorption process
Once done, close valve 2 and remove the evacuated sample.
Holder 109 and assembly A are
Connect to yoint 128 and close stopcock 19
Ru. Therefore, the sample holder 109 is suitable for use in a liquid bath.
It is a very important position. So valves 1, 4, 5 and
6 and activate the exhaust pump 105 to activate the system.
Exhaust. After about 5 minutes, the exhaust will be completed and stop.
19 is opened and valves 5 and 6 are closed. Then the valve
3 and one of valves 7 to 10 is opened;
Stabilize the mass flow controller. This stabilization
It takes about 5 minutes. Next, select an appropriate command voltage
Then, valve 1 is closed and valve 6 is opened at the same time. Adsorbent
are the open and closed states mentioned above at this point.
conduit 21 via an input path defined by a valve in
1 flows into the sample holder, and the pressure begins to rise.
Ru. Therefore, we performed pressure vs. time measurements and measured the surface of the sample.
Find the product. When executing the desorption mode, the sample holder 10
The outgassed samples, including 9, were aspirated as described above.
Place it at the same position as the starting point of arrival mode. valve 2
remains closed during the entire operating process. Then the valve
Open 1, 4, 5 and 6 to evacuate the system.
Ru. At this time, the stopper 19 is opened. That's it
For samples, close valves 1 and 6 and close valves 3 and 7.
to 10 to select the relevant adsorbent.
By doing so, the adsorbent becomes saturated. This saturation
During the process, valves 4 and 5 remain open.
Ru. The mass flow rate is initially at a high level.
It can be. That is, when the detachment mode is performed
This is because no pressure readings are taken during saturation.
Ru. This saturation generally means that all the pores of the sample are in the liquid phase.
Long from where it must be filled with desorbent
For example, about 1 hour to about 8 hours is required.
It will be done. However, as a matter of convenience,
To the extent that the adhesive condenses on the walls of the sample holder 109
Care should be taken not to oversaturate the sample. too
If such an event occurs, the desorption period may be unnecessarily shortened.
becomes longer. Once the sample is saturated, desorption mode
can be started. This desorption mode is
5 remains open and valves 3 and 4 are closed;
It begins by opening valves 1 and 6. this
A single mass flow controller is required to open and close such valves.
necessitated by the fact that it operates only in the direction of
It is essential. As a result, the exhaust
is the mass flow controller in the forward direction of motion.
The material to be desorbed must be suctioned through the tube. trial
If the material is properly saturated, the desorbent pressure
remains constant for several minutes. When calculating the calibration amount
considers the time t=0 when the pressure starts to drop.
Ru. At this point, the sample holder wall and sample
All the condensed and desorbed agent between the particles is removed.
Ru. However, pressure detection and
Recording begins. Implements combined mode of adsorption and desorption mode
To do this, first use adsorption mode to collect the sample.
During adsorption and desorption saturation and pressure vs. time readings
be collected. The examples described below serve as specific illustrations of the invention.
It is given as follows. Therefore, the present invention
is limited to the details of the examples described below.
I would like it to be understood that there is no such thing. In addition, as described in this specification,
Parts and hundreds in the examples and other descriptions below.
Fractions are in parts by weight or unless otherwise stated.
understood to be given as a weight percentage
stomach. In all of the following examples, FIGS.
The preferred embodiments mentioned in connection with the description of FIG.
The apparatus according to the example was used. Example 1 In this example, the suction mode is
Repeat the blank test cycle for calibration on the
Then, a graph representing the pressure vs. time relationship as shown in Fig. 5 is created.
Got rough. Table 1 below shows the related parameters used.
ta is posted. Table 1 Adsorbent: N₂ Saturation pressure: 760mmHg Chamber volume (V_L): 20.01c.c. Specimen holder volume (V_S.H.): 21.60c.c. Liquid nitrogen bath temperature (T_S.H.): 77.2〓 Pipe temperature (T_L): 296.0〓 Partial pressure range: 0 to 0.263 Number of pressure/time data points sampled: 1.260 As mentioned above, this operating cycle is in adsorption mode.
I went. From formula 1, the flow rate is 0.5ml/min at S.T.P.
It was calculated that engaged to computer
Pressure versus time from Hwlett Packard 7225A printer
The relationship between them was plotted. As is clear from Figure 5
, a straight line is obtained, which has essentially constant quality
Represents flow rate. The degree of dispersion of data points is (1)
from the pressure value corresponding to the best straight line across the data points.
Find the absolute value of the deviation of the pressure value at each data point.
(2) average the absolute deviation values, and (3) use this average value as the
Relate this value to the stem pressure and express this value as a percentage.
It was calculated by expressing Dispersity is one way to express the consistency of flow rate.
Ru. In this example, all three plots were
The dispersion rate was 0.8%. Example 2 In this example, the calibration block is
I did a rank test cycle. Table 2 below shows the
The relevant parameters are presented. Table 2 Desorbent: N₂ Saturation pressure: 760mmHg Chamber volume (V_L): 36.68c.c. Specimen holder volume (V_S.H.): 21.60c.c. Liquid nitrogen bath temperature (T_S.H.): 77.2〓 Partial pressure range (P/P_s): 1.0 to 0 Pipe temperature (T_L): 296〓 Number of pressure/time data points sampled: 30000 The mass flow rate was measured at 0.30 ml/min at 0.24% dispersion.
calculated. Generated by computers and printers.
A plot or
The graph is shown in FIG. From Figure 6
As you can see, this graph consists of three line segments A, B and
It is divided into C and C. Line segment A is the condensation inside the sample holder.
Constant pressure created by compressed desorbed material
represents power. At the end of line segment A, all the condensed
Adhesive is removed and the graph therefore slopes steeply.
This gradient section substantially passes through the line segment B.
remains constant. Therefore, line segment B is essentially
Represents the extraction of the desorbent at a constant flow rate. At the end of line segment B, at a pressure close to absolute vacuum, the gradient
changes again. The mass flow controller controls the flow rate.
This is the point where it becomes virtually impossible to maintain a constant value.
It is. However, this point is approximately 0.02
Partial pressure (P/P_s) does not occur until reaching This partial pressure
calculates the pore size distribution of the sample and virtually completes it.
the partial pressure required to obtain the desorption isotherm.
This is a really low value. Example 3 In this example, we will perform the actual adsorption degree difference.
Ta. The sample selected for surface area determination or measurement is
281 to 297 m depending on the measurement method used²/g
A silicone with a surface area reported to be between
Car-alumina ASTM Standard No.N10074
Ru. Calibration blank test performed in advance (Example 1)
The mass flow rate was determined using the results of and 2).
The sample was placed in the sample holder under vacuum at 400°C for 700 min.
Gas was released inside the da. Relevance of adsorption in this example
The parameters are summarized in the table below. Table 3 Adsorbent: N₂ Sample type: Silica-Alumina Sample weight: 1.074 (g) Sample density: 3.2 (g/c.c.) Saturation pressure: 760.00 (mmHg) Chamber volume (V_L): 20.01c.c. Specimen holder volume (V_S.H.): 21.60c.c. Liquid nitrogen bath temperature (T_S.H.): 77.2 (〓) Pipe temperature (T_L): 315 (〓) Mass flow rate: 0.30 (ml/min) Partial pressure range: 0 to 0.263 Total number of pressure/time data points sampled: 25440 Pressure/time data sampled by computer
Approximately equally spaced data points on the graph
Regarding 10 sampled chamber pressure points, for convenience, a table is shown below.
The data were summarized in 4. actual plot or song
The lines are shown in FIG. Reported sampling
The reference pressures corresponding to the chamber pressures are also shown in Table 4.
S.T.P. of adsorbed adsorbent per gram of sample
The volume at and the relative adsorbed amount at which this amount was adsorbed.
Agent pressure (P/P_s) is calculated using Equation 2 and the total pressure/time data.
From the difference between CRP and SCP using the database
Obtained by calculation.

[Table] The linearized version of the BET equation is the relative pressure (x
axis) and at each relative pressure as the y-axis.
It is plotted from the value calculated for Pr/V(1-Pr). The slope and y-intercept of the plot (curve) were calculated to be 0.000 and 0.015, respectively. The surface area was then determined to be 284.2 m ² /g. Example 4 This example illustrates the desorption mode and employs three different experiments. In the first experiment, a perforated glass sample, Sample A, was placed in desorption mode. In Experiment 2, a different sample of perforated glass was used, namely Sample B. In experiment 3, 50% by weight of glass samples A and B
A mixture of ratios was employed. Each sample was degassed under vacuum at 375°C for 700 minutes. Each sample was then saturated with N ₂ desorbent until the sample saturation pressure reported in Table 5 was achieved in the sample holder.
Desorption was then started at the mass flow rates reported in Table 5. The computer sampled the decrease in pressure as a function of time at a frequency of about 60 data points per minute and plotted pressure versus time as shown in FIG. In Figure 8, plot (curve) 1
corresponds to sample A, plot 2 corresponds to sample B, and curve 3 corresponds to a mixture of samples A and B. Plot 3 shows the pressure/time curves attributed to sample A and sample B according to the method and apparatus of the present invention.
It is illustrated that high resolution can be obtained between the pressure/time curves resulting from . Specifically, part A of plot 3 corresponds to part a of plot 1,
Part B of plot 3 corresponds to part b of plot 2. However, this degree of resolution is limited by the △
This can be understood more clearly from the pore size distribution plot of Vdsb/△Rp. As can be seen from Fig. 9, the hole radius of sample 3 in plot 3 of Fig. 8 is mainly
81 angstroms, plot 3 in Figure 8.
The pore radius of sample B in is primarily 55 angstroms. This corresponds to the pore size distribution obtained from Plots 1 and 2, and a summary of suitable test conditions is summarized in Table 5. It can be seen that at a pressure of about 140 mmHg, a discontinuity point appears in the graphs shown in FIGS. 5 and 7. These discontinuities are a result of the automatic region setting of the A/D converter used to generate the graphs in Figures 4 to 8, and are a result of the raw data used as the basis for the calculations. It is not something that comes into being.

[Table] Total number of points The principles, preferred embodiments, and modes of operation of the present invention have been described above. However, this invention is not to be construed as limited to the particular forms disclosed herein. What has been disclosed herein is set forth by way of example only, and not with a view to limitation, and should therefore be construed as illustrative only. Variations and modifications may occur to those skilled in the art without departing from the spirit of the invention.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the preferred components of the apparatus of the present invention, FIG. 2 is a simplified diagram showing the components of each part shown in FIG. 1, and FIG. 4 is a more detailed diagram of the mass flow controller circuit board 401 as well as the flow control means shown in block 403 of FIG. 3; FIG. FIG. 5 is a diagram showing a pressure versus time graph obtained in the adsorption control calibration operation generated by Example 1;
FIG. 6 is a graph showing pressure versus time obtained in the desorption control calibration operation generated in Example 2, FIG. 7 is a graph showing pressure versus time in adsorption mode obtained in Example 3, FIG. 8 is a diagram showing a combination of three pressure versus time graphs for desorption modes obtained in Example 4, and FIG. 9 is a diagram showing a graph representing the pore size distribution generated according to Example 4. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10:
Exhaust solenoid valve (ASCOTM), 14: Heating block, 16: Power supply, 19: Stop stock, 20, 1
13: Liquid level controller, 101, 10
2, 103, 104: gas cylinder, 108: transducer, 109: sample holder, 11
0': Sample, 111: Liquid bath container, 112: Liquid bath, 115: Heater, 117: Computer, 1
18: Stop paper recorder, 119: Box, 121: A/D converter, 122: Capillary neck, 123, 124: Ground glass joint, 1
25', 126': Capillary path, 127': Ground glass joint, 128: Glass joint, 12
9: Bath level, 135, 136: Metal glass connector, 125, 126, 200, 201, 20
2,203,204,205,206,208,
209, 210, 211: Pipeline, 212, 21
3: Coil part, 301: Mass flow controller,
302: thermal response valve, 311: pressure controller,
401: circuit board, 402, 412: housing,
403: flow controller block, 404: thermistor, 405: proportional-integral-derivative (PID) controller, 406: heating strip, 407: fan, 408: detection bridge circuit, 409: linearization circuit, 410: amplifier, 411: detection coil, 5
01,502: Bridge resistor, 505: Switch, 506: Transformer, 510: Voltmeter, 517:
bridge circuit, 520: selector, 600: comparison controller circuit;

Claims (1)

[Claims] 1. A method for determining the amount of a gaseous adsorbent adsorbed by a solid adsorbent, comprising: (a) providing an evacuated chamber of known volume and discharging the adsorbent into the chamber; (b) at a continuous and known substantially constant mass flow rate for a sufficient period of time to effect adsorption of at least a portion of the adsorbed material by said adsorbent; A known amount of gaseous adsorbent is introduced into the chamber containing the sample, where the mass flow rate is not greater than the equilibrium adsorption amount of the adsorbent by the adsorbent and at standard temperature and pressure conditions. (c) establishing an equilibrium pressure of the adsorbent that is the sampling chamber pressure when introduced into the chamber as a function of time; and (d) to obtain a continuous adsorption isotherm, the sampling chamber pressure of the adsorbent, the mass flow rate of the adsorbent, and the time required to achieve said sampling chamber pressure are determined as described above at said sample chamber pressure. A method comprising correlating the amount of adsorbent adsorbed by the adsorbent. 2. The method of claim 1, wherein the volume and temperature of the chamber are maintained substantially constant during the introduction of the adsorbent. 3 Adsorbent partial pressure (P/
P _s ) The adsorbent is continuously introduced into the chamber for the time necessary to achieve P s
The method described in section. 4. The method of claim 3, wherein the adsorbent is introduced into the chamber for a period of one minute to achieve an adsorbent partial pressure of greater than about 0.35. 5. The method of claim 3, wherein the adsorbent is introduced into the chamber for a sufficient time to achieve an adsorbent partial pressure of about 1.0 in the chamber. 6. A method according to any one of claims 1 to 5, wherein the mass flow rate of the adsorbent is from about 0.05 to about 0.7 ml/min at standard temperature and pressure conditions. 7. The mass flow rate of the adsorbent is from about 0.2 to about 0.5 ml/min at standard temperature and pressure conditions, and during the introduction of the adsorbent into the chamber, the possible fluctuations in the mass flow rate are approximately The method according to any one of claims 1 to 5, which is less than ±0.15%. 8. The mass flow rate of the adsorbent is from about 0.2 to about 0.4 ml/min at standard temperature and pressure conditions, and any fluctuations that may occur in the mass flow rate during introduction of the adsorbent into the chamber are such that the mass flow rate 6. A method according to any one of claims 1 to 5, wherein the method is less than about ±0.15%. 9. The method according to claim 1, wherein the adsorbent is nitrogen. 10. The method according to claim 1, wherein the adsorbent is a chemisorbent substance. 11 (a) providing an evacuated chamber of known volume and temperature in the absence of a sample of adsorbent; (b) establishing a reference pressure, the adsorbent equilibrium pressure, in the chamber as a function of time upon introduction of the adsorbent; and (b) determining the change in reference pressure per unit time under known volume and temperature conditions. 2. The method according to claim 1, wherein the mass flow rate of the adsorbent is determined by referring to a blank test result to which the mass flow rate can be correlated. 12 The chamber pressure sampled as a function of time is set in a manner sufficient to record from about 100 to about 10,000 sampled chamber pressure data points during the course of adsorbent introduction. The method described in item 1. 13. The method according to claim 1, wherein the amount of the adsorbent adsorbed by the adsorbent is expressed as a volume, and the volume is correlated with the sampled chamber pressure to determine the surface area of the adsorbent. 14 The surface area of the solid adsorbent is about 0.01 to about 1500
2. A method according to claim 1, wherein m ² /g. 15. In a method for determining the amount of desorbent desorbed as a gas from a solid desorbent saturated with condensed desorbent, (a) a sample of the desorbent having previously degassed and condensed desorbent; (b) for a period at least sufficient to desorb the condensed desorbent from the pores of the sample; , removing said desorbed agent from said chamber at a continuous, known, substantially constant mass flow rate not greater than the equilibrium desorption amount of desorbed agent from the desorption medium and independent of sample pressure; (c) said chamber; (d) setting the equilibrium pressure of the desorbent to be the sampling chamber pressure as a function of time as the desorbent is removed from the sample chamber, and (d) sampling the desorbent to obtain a continuous desorption isotherm. A method comprising correlating a chamber pressure, a mass flow rate of desorbed agent, and the time required to achieve the sampling chamber pressure with the amount of desorbent desorbed at the sampling chamber pressure. 16. The method of claim 15, wherein the volume and temperature of the chamber are maintained substantially constant during removal of the desorbent. 17. Continuously removing the desorbent from the chamber for a period sufficient to achieve a partial pressure of the desorbent in the chamber of less than about 0.2.
The method described in section. 18. The method of claim 17, wherein the desorbent is removed from the chamber for a period sufficient to achieve a partial pressure of the desorbent in the chamber of less than about 0.1. 19. The method of claim 17, wherein the desorbent is removed from the chamber for a period sufficient to achieve a partial pressure of desorbent in the chamber that is less than about 0.04. 20. The method of any of claims 15 to 19, wherein the mass flow rate of the desorbent is about 0.2 to 0.7 ml/min at standard temperature and pressure conditions. 21 The mass flow rate of the desorbed agent is from about 0.2 to about 0.4 ml/min at standard temperature and pressure conditions, and possible variations in mass flow rate are removed from the chamber with a partial pressure of the desorbed agent not less than 0.03. 20. A method according to any of claims 15 to 19, wherein the mass flow rate of the desorbent is not greater than ±0.15% between . 22 The desorbent mass flow rate is approximately 0.2 to 0.3 ml/min at standard temperature and pressure conditions, and possible fluctuations in mass flow rate are such that the desorbent mass flow rate is approximately 0.2 to 0.3 ml/min while the desorbent mass flow rate is removed from the chamber at a desorbent partial pressure not lower than 0.02. Claim 1: not greater than ±0.15% of the mass flow rate of the desorbent
The method according to any one of Items 5 to 19. 23 Claim 1 in which the agent to be desorbed is nitrogen
The method described in Section 5. 24 The desorbent mass flow rate is determined by (a) providing an evacuated chamber of known volume and temperature in the absence of a desorbent sample;
the chamber has a condensed desorbent, the desorbent being removed as a gas from the chamber at a substantially constant mass flow rate according to claim 15 in the presence of the sample; (b) setting a reference pressure, a desorbent equilibrium pressure, in the chamber as a function of time;
16. The method of claim 15, wherein the desorbent mass flow rate is determined with reference to blank test results correlated from changes in reference pressure per unit time under known volume and temperature conditions. 25. The desorbent sampled chamber pressure as a function of time is established in a manner sufficient to record from about 500 to about 40,000 desorbed agent sampled chamber pressure data points during the desorbent removal process. 16. The method according to claim 15. 26. The method according to claim 15, wherein the amount of the desorbent to be desorbed by the desorbent is expressed as a volume, and the volume is correlated with the sampled chamber pressure to determine the surface area of the desorbent. 27 The surface area of the desorption medium is approximately 0.01 to 1500 m ² /g
16. The method according to claim 15, which may be 28 In an apparatus for determining the amount of gas adsorbed by a solid adsorbent sample or the amount of gas desorbed from a solid desorbent sample, (1) the solid sample and the gas introduced into the chamber means or the chamber means; chamber means defining at least one chamber of known constant volume for containing gas to be removed from the sample pressure; (3) establishing the pressure of said gas as a function of time within said chamber means as said gas is introduced into or withdrawn from said chamber means; (4) controlling a mass flow rate of said gas being introduced into said chamber or said gas being removed from said chamber such that: (a) said mass flow rate is at least about the same as said gas in said chamber; substantially constant over the entire partial pressure range from 0.02 to about 1.0; and (b) not greater than the equilibrium adsorption of gas by the adsorbent sample during the introduction of said gas and desorption during withdrawal of said gas. (5) means for evacuating the gas from the chamber means through the control means during removal of the gas from the chamber means; ) means for maintaining a known temperature of a gas within said chamber substantially constant to obtain a continuous adsorption or desorption isotherm. 29. The claim wherein the control means is a mass flow controller having an electronically actuated variable opening for controlling the mass flow rate of gas being introduced into or being removed from the chamber means. The apparatus according to scope 28. 30. The control means controls the mass flow rate of the gas being introduced into or removed from the chamber means to be from about 0.05 to about 0.7 ml/min at standard temperature and pressure conditions. 29. The device according to claim 28, wherein the device is capable of: 31 The control means is capable of controlling the mass flow rate of the gas from about 0.02 to about 0.05 ml/min at standard temperature and pressure conditions, and the variation in the mass flow rate during the introduction or withdrawal of the gas is within the range of ± of the mass flow rate. 29. The device of claim 28, wherein the amount is not greater than 0.15%. 32. The control means is capable of controlling the mass flow rate of the gas to be from about 0.2 to about 0.4 ml/min at standard temperature and pressure conditions, and the variation in the mass flow rate is greater than about ±0.15% of the mass flow rate. 29. The apparatus of claim 28, wherein: