JPS586904B2 - Standard gas generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a standard gas generator used for calibrating a gas analyzer.

For calibration of a gas analyzer, a constant concentration standard gas filled in a cylinder or a standard gas obtained from a standard gas generator is generally used.

A conventional standard gas generator dilutes a high-pressure pure gas (100% pure gas) filled in a cylinder to generate a constant concentration standard gas.

Therefore, there is a problem in that the components constituting the standard gas are limited to those that can be filled into a cylinder as a high-pressure gas.

Furthermore, the accuracy was not satisfactory.

It is an object of the present invention to provide a highly accurate standard gas generator that is not subject to such limitations.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an example of a standard gas generator according to the present invention.

In the figure, 1 is a tank, 2 is an analyzer, 3 is an annular conduit that partially includes the tank 1, 4 is a pump disposed in the annular conduit 3, 5 is a solenoid valve disposed in the annular conduit 3, and 6 ,7
are a gas inflow path and a gas outflow path, respectively.

The gas inflow path 6 and the gas outflow path 7 are connected to the annular pipe 3 with the solenoid valve 5 sandwiched therebetween.

8 and 9 are electromagnetic valves disposed in the gas inflow path 6 and gas outflow path 7, respectively; 10 is a sample valve disposed in the annular pipe 3; and 11 is a measuring tube provided in the sample valve 10.

The sample valve 10 is in either a connected state shown by a solid line or a connected state shown by a broken line in the figure.

12 and 13 are inflow paths to the sample valve 10, 14 are outflow paths, and 15 and 16 are electromagnetic valves arranged in the inflow paths 12 and 13, respectively.

17 is a solenoid valve disposed in the annular pipe 3; 18 and 19 are pipes connecting the annular pipe 3 and the analyzer 2 near both sides of the solenoid valve 17; and 20 and 21 are pipes 18 and 19. This is a solenoid valve located at

A compressed diluent gas is supplied to the gas inflow path 6, and a reference fluid and a mixed (to be diluted) fluid are supplied to the inflow paths 12 and 13, respectively.

The reference fluid and the mixed fluid may be gases or liquids, but if they are liquids, they should be
It is necessary to adjust the temperature etc. inside the annular pipe 3.

As the reference fluid, select one that is easily obtained and can be a stable gas, and that has an analyzer that can analyze the gas concentration.

The analyzer 2 is for determining the reference fluid (gas) concentration in the gas within the annular pipe 3.

Next, the operation of this embodiment will be explained.

First, the solenoid valves 8, 9, 15, 20, and 21 are opened, and the solenoid valves 5, 16, and 17 are closed, and the sample valve 10 is brought into the state shown by the solid line in the figure.

Thereby, the gas in the tank 1 and the annular pipe 3 is discharged to the outside via the gas outlet path 7 by the diluent gas.

These interiors are then filled with diluent gas.

On the other hand, the inside of the measuring tube 11 of the sample valve 10 is filled with the reference fluid.

Next, the solenoid valves 5 and 17 are opened, and the solenoid valve 9 is closed.

As a result, the pressure within the tank 1 and the annular pipe 3 increases.

When this pressure reaches a constant value, the solenoid valve 8 is closed.

Next, the sample valve 10 is connected as shown by the broken line in the figure, and then the pump 4 is driven.

Circulation is generated by the action of the pump 4, whereby the reference fluid (a certain amount) in the metering tube 11 and the dilution gas (a certain amount) in the tank 1 and the annular pipe 3 are mixed.

After sufficient mixing, the pump 4 is stopped, the sample valve 10 is connected as shown by the solid line in the figure, the solenoid valve 15 is closed, and the solenoid valve 16 is opened.

Therefore, the inside of the metering tube 11 is filled with the mixed fluid.

Then, the sample valve 10 is again connected as shown by the broken line in the figure, and then the pump 4 is driven in the same way as in the case of the reference fluid.

As a result, the mixed fluid, reference fluid, and diluent gas are sufficiently mixed to obtain a standard gas.

Here, the solenoid valves 20 and 21 are opened, the solenoid valve 17 is closed,
Reference fluid (gas) in the gas in tank 1 with analyzer 2
Measure concentration.

Then, the mixed fluid concentration in the standard gas is determined from this reference fluid concentration.

Assuming that the dilution ratio is sufficiently large (this assumption is correct in most cases), the relational expression for the mixed fluid concentration in the standard gas is as follows: DsO: reference fluid concentration (mixed fluid) Dsl: Reference fluid concentration (after mixing) DxO: Mixed fluid concentration (before mixing) Dx1: 〃 (after mixing) l: Volume of measuring tube 11 L: Total volume of tank 1 and annular pipe 3, etc. PO:
Pressure of each fluid in the measuring tube 11 (before mixing) P1: Pressure in the tank 1 and annular pipe 3 (after mixing) T0 = Absolute temperature of each fluid in the measuring tube 11 (before mixing) T1: Absolute temperature in the tank 1 and in the annular pipe 3 (after mixing) r: Indicated by dilution rate.

Therefore, DX1 is denoted by .

Here, since the reference fluid and mixed fluid are gases with a constant concentration created by physical means, their concentration DxO
and DsO are known and can also be used.

Therefore it is possible.

Then, by opening the electromagnetic valve 9, the standard gas having the mixed fluid concentration Dxl is supplied to the outside.

Although the formula for determining Dxl is shown for the case where the reference fluid and mixed fluid are gases, the same applies to the case where the reference fluid and mixed fluid are liquids.

For example, when the reference fluid or mixed fluid is a liquid (pure substance), instead of DsO and DxO, Ds: Density of reference fluid at absolute temperature T0 DX: Density of mixed fluid at absolute temperature T0 Ms: Reference Molecular weight MX of fluid: The molecular weight of the mixed fluid may be substituted into equation (2).

In any case, since the mixed fluid concentration in the standard gas is determined regardless of l, L, T1, and P1, a highly reliable (highly accurate) standard gas can be obtained.

In particular, it is preferable to use gas or liquid for both the reference fluid and the mixed fluid because the mixed fluid concentration is determined regardless of P0 and T0.

FIG. 2 is a block diagram showing a part of another example of the apparatus of the present invention (the same parts as in FIG. 1 are given the same reference numerals).

This actual case is for obtaining a standard gas containing various mixed fluids in a fixed ratio.

Specifically, a mixed fluid inflow path is added and a solenoid valve is placed there.

The mixed fluid supplied to the added inflow channels 22 to 24 and the electromagnetic valves 25 to 27 is sequentially supplied to the sample valve 10, similar to the mixed fluid supplied to the inflow channel 13 and the electromagnetic valve 16.

Note that the tank 1 in the above description does not need to be particularly provided when the volume of the annular pipe 3 and the like other than this is large.

Further, although the sample valve 10 is shown as a means for injecting a fixed amount of mixed fluid, any injection means such as a syringe may be used.

Furthermore, although not specified in the above description, automatic operation is possible if the electromagnetic valves and the like are operated in a certain sequence.

Further, it may be constructed using valves other than electromagnetic valves.

As explained above, according to the present invention, it is possible to realize a standard gas generator that can generate a standard gas that contains as a constituent gas a gas that cannot be filled into a cylinder at high pressure.

In addition, since it is not susceptible to external factors (temperature and pressure, etc.) in principle, it is possible to obtain a highly accurate standard gas.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of a standard gas generator according to the present invention, and FIG. 2 is a block diagram showing a part of another embodiment of the standard gas generator according to the present invention. 1... Tank, 2... Analyzer, 3
...Annular pipe line, 4...Pump, 5...
...Solenoid valve, 6...Gas inflow path, 7...
...Gas outflow path, 10...Sample valve,
11...Measuring tube.

Claims (1)

[Scope of Claims] 1. A tank having a predetermined internal capacity, an annular conduit including the tank as a part and having a constant capacity, and a first and second tank disposed in respective predetermined parts of the annular conduit a second opening/closing solenoid valve;
a gas inflow path and a gas outflow path which are connected to the annular pipe so as to sandwich the first on-off solenoid valve and into which a predetermined diluent gas, etc. are introduced and taken out, respectively; and a gas outflow path between the tank and the first on-off solenoid valve. a fluid injection means disposed in a predetermined portion of the annular conduit for injecting desired amounts of a predetermined reference fluid and a mixed fluid into the annular conduit, and connected to the annular conduit so as to sandwich the second on-off solenoid valve. between an analyzer that collects a predetermined amount of gas in the annular pipe through a gas introduction pipe and a gas outlet pipe and detects the reference fluid concentration in the gas; and between the tank and the second opening/closing solenoid valve. a pump disposed in a predetermined portion of the annular conduit to generate a reflux in the annular conduit, the diluent gas, the reference fluid, and the mixed fluid taken into the annular conduit are mixed; The mixed fluid concentration in the standard gas is determined from the reference fluid concentration detected by the analyzer, and the desired standard gas is supplied to the outside from the gas outlet path. Standard gas generator. 2 first and second connected to the predetermined portion of the annular pipe
The reference fluid and the mixed fluid are individually guided through the third and sixth connection ports to which both ends of a metering tube having a predetermined internal volume are connected, respectively, and the respective opening/closing solenoid valves. a fifth connection port to which an inflow channel is connected; and a fourth connection port to which an outflow channel for discharging fluid led from the inflow channel is connected; a first state in which the ports communicate with the second, fourth, and sixth connection ports, respectively; and a state in which the first, third, and fifth connection ports communicate with the sixth, second, respectively.
, and the second state of communicating with the fourth connection port are alternately repeated, and the fluid injection means is comprised of a sample valve configured to alternately repeat the following: . 3 The inflow path connected to the fifth connection port is configured such that the reference fluid and the plurality of mixed fluids having mutually different concentrations are individually guided in a predetermined order through respective open/close solenoid valves. A standard gas generator according to claim 2, comprising: