CN113218815B - Pore channel integrated module and method for determining material density based on gas displacement method - Google Patents
Pore channel integrated module and method for determining material density based on gas displacement method Download PDFInfo
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- CN113218815B CN113218815B CN202110418113.3A CN202110418113A CN113218815B CN 113218815 B CN113218815 B CN 113218815B CN 202110418113 A CN202110418113 A CN 202110418113A CN 113218815 B CN113218815 B CN 113218815B
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- G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
- G01N9/02—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by measuring weight of a known volume
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
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- G01N2009/022—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by measuring weight of a known volume of solids
- G01N2009/026—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by measuring weight of a known volume of solids the volume being determined by amount of fluid displaced
- G01N2009/028—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by measuring weight of a known volume of solids the volume being determined by amount of fluid displaced a gas being used as displacement fluid
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Abstract
The invention provides a pore channel integrated module and a pore channel integrated method for measuring material density based on a gas displacement method, and belongs to the technical field of material density measurement. The module comprises a cover body, a cavity body and a sample cup, wherein the cover body and the cavity body are connected and fastened through screws, and gas sealing is carried out through an O-shaped ring. The module measures the atmospheric background pressure through a pressure sensor, and measures the corresponding background temperature through a temperature sensing element attached to the surface of a pore module of the densimeter; helium enters the sample cavity through the air inlet valve, the pressure sensor measures the air inlet pressure, and the temperature sensing element measures the corresponding air inlet temperature; helium enters the reference cavity through the pressure equalizing valve, the pressure equalizing pressure is measured by the pressure sensor, the corresponding pressure equalizing temperature is measured by the temperature sensing element, the volume of the sample stored in the sample cavity is calculated according to the gas state equation, and the skeleton density or the apparent density of the sample is calculated by combining the weighed sample mass. The invention has the advantages of less gas leakage points, good gas tightness and temperature stability and high automation degree, and ensures the repeatability and consistency of density measurement.
Description
Technical Field
The invention relates to the technical field of material density measurement, in particular to a pore channel integrated module and a pore channel integrated method for measuring material density based on a gas displacement method.
Background
Density is the volume occupied by a unit mass of material. For solids, the solid is divided into skeleton density, apparent density, tap density and the like according to different occupied volumes, and is a strength index for measuring the performances of heat insulation, heat preservation, noise reduction, adsorption and the like of materials such as porous materials, particles, powder and the like. The traditional density measurement adopts a liquid discharge method, the measurement process is complex, the human influence factors are many, the material damage is large, the secondary pollution is serious, many water-forbidden materials cannot be measured, the material measurement range is limited, and the method cannot meet the requirements of the development of modern new materials. The exhaust method can avoid the defects, realize complete automation and intellectualization and improve the measurement precision of the density of the sample.
The exhaust method is a gas replacement method based on the Archimedes principle, original liquid is replaced by helium which is not adsorbed by a material, the helium belongs to a monoatomic inert molecule and can enter micropores of the material to really measure the framework volume of the porous material, and the material cannot be damaged in the test process. However, the exhaust method still has the following problems:
(1) large clearance volume
When the density measuring instrument adopts pipelines made of different materials such as a steel pipe, a glass pipe and a plastic pipe to be connected, a large amount of clearances are formed at the joints of the pipelines and the valve and the cavity, and because the gas has compressibility, the gas stays at the positions, the ratio of the volume of the measured object to the total volume is easily reduced, and the change of the small volume of the substance is not easy to cause the change of the gas pressure, thereby reducing the measuring resolution.
(2) The temperature of the gas is not uniform
In the process of measuring the density of the material, gas is distributed at each part such as a pipeline, a connecting point, a cavity around the material and the like, and because the material of each part is different and the difference of the heat conductivity is large, the heat exchange speed between the gas staying at the parts and the external environment is different, the gas at each part is always in the process of temperature change in a short time of density measurement, the volume of the gas corresponding to each part is changed along with the change of the gas, and the accuracy of the measurement result is poor.
(3) The difference between the ambient temperature and the gas temperature is large
Helium enters the measuring cavity from the external gas cylinder, and is a temperature change process. The measuring instrument is internally provided with heating elements such as a circuit board and an electromagnetic valve, and is externally provided with a heat-insulating outer cover such as a case shell, so that the ambient temperature of gas in the measuring process is different from the temperature of the gas in a gas cylinder, the measuring process of the exhaust method is completed within a few minutes, the specific heat capacity of the gas is small, the heat exchange is difficult to complete within a short time under the condition of low temperature difference, and the stable temperature is reached.
The plate-type electromagnetic valve is a fluid control component which is sealed by an O-shaped ring of an air inlet and an air outlet and a flat plate plane and is fastened by screws, has small volume, light weight, less power consumption, no thread and strong sealing property, and realizes automatic control by power-on and power-off. The method is characterized in that a metal material with good heat conduction is used as a pore channel module, pore channels with small diameters and cross-linked with each other are drilled in the metal material body according to a mounting structure of a plate-type electromagnetic valve, a pressure sensor, an air inlet, an air outlet and a sealing plug, porous filler with good heat conduction is filled in the pore channels, so that gas is heated to be close to the temperature of the metal material in the process of entering the pore channel module, the stability and uniformity of the gas temperature for measurement are ensured, and a set of integrated pore channel module with small clearance volume, rapid gas heating and uniform temperature field in the measurement process is formed. Therefore, it is desirable to design a via integrated module and a testing method for determining material density based on a gas displacement method.
Disclosure of Invention
The invention provides a pore channel integrated module and a pore channel integrated method for measuring material density based on a gas displacement method, aiming at solving the problems of large clearance volume, uneven gas temperature and the like when the material density is measured by the gas displacement method.
The module comprises a cover body, a cavity body and a sample cup,
wherein, the cover body comprises a hand dish outer cover, an inner cover screw, a hand dish inner cover, a movable disc, a spinning fastening cover, a sealing cover, a fastening cover base, a sample pool sealing ring and a base screw, the hand dish outer cover is connected with the hand dish inner cover through clearance fit, the hand dish outer cover drives the hand dish inner cover to rotate through friction force, when the hand dish inner cover stops rotating, the hand dish outer cover can still rotate freely, the friction force between the hand dish outer cover and the hand dish inner cover is controlled by the clamping force of fingers of an operator, the spinning hand dish inner cover is connected with the fastening cover through the inner cover screw and fastened, the spinning fastening cover is provided with the movable disc, the spinning fastening cover is connected with the sealing cover below, the sealing cover covers on the sample cup, the sample cup is arranged in the cavity body, the fastening cover base is fastened and connected with the density meter pore passage module through four base screws, when the hand dish outer cover is rotated, the hand dish outer cover drives the hand dish inner cover to rotate through the friction force, the inner cover of the hand disc drives the spinning fastening cover to rotate, and the external thread of the spinning fastening cover is screwed into the internal thread of the base of the fastening cover until the sample cell sealing ring on the sealing cover presses the sealing boss of the sample cavity to form sealing;
the cavity body comprises a densimeter pore passage module, a pressure sensor, sensor fastening screws, a valve hole plug column, a sealing plug, plug fastening screws, an air inlet valve, a pressure equalizing valve and a gas release valve, wherein the three plug fastening screws are screwed into corresponding plug fastening screw holes, the sealing plug is fastened at a sealing position through the edges of the three plug fastening screws, the pressure sensor is fastened in the pressure sensor hole by the three sensor fastening screws in the same fixing mode of the sealing plug, and the air inlet valve, the pressure equalizing valve and the gas release valve are respectively fastened in respective valve fastening screw holes by four screws.
The outer cover of the handwheel is made of organic materials, and the upper end of the outer cover is milled with a groove for sticking marks; the outer circle of the inner cover of the hand dish is processed into a stripe shape, so that the friction force when the outer cover of the hand dish is rotated is increased; external threads are machined on the outer circle of the spinning fastening cover; an internal thread is processed on the inner circle of the fastening cover base; the sealing plug comprises an O-shaped sealing ring; the pressure sensor itself has an O-ring.
The tested sample in the sample cup is solid material or liquid material.
The density instrument pore module is provided with a sample cavity sealing boss, the front side is provided with an air inlet valve inlet, an air inlet valve outlet, an equalizing valve inlet, an equalizing valve outlet, a deflation valve inlet and a deflation valve outlet, a slender pore is arranged inside the density instrument pore module, the end of the air inlet valve inlet corresponding to the slender pore is an air inlet, the opening of the air inlet is arranged behind the density instrument pore module, the end of the air inlet valve outlet corresponding to the slender pore is connected with the slender pore connected with a pressure sensor hole, the end of the equalizing valve inlet corresponding to the slender pore is connected with the sample cavity, the end of the equalizing valve outlet corresponding to the slender pore is connected with the bottom of a reference cavity, the end of the deflation valve inlet corresponding to the slender pore is connected with the upper part of the reference cavity, the end of the deflation valve outlet corresponding to the slender pore is connected with a deflation port, the deflation port is opened behind the density instrument pore module, and slender rods made of metal materials with good heat conduction are arranged in the slender pore, the thin rod material is preferably silver material and red copper material, and the gap between the thin rod and the corresponding slender pore canal is less than 0.2 mm.
The valve hole plug is stuffed in the elongated hole of the density meter pore module, on one hand, the valve hole plug can occupy the volume of the pore, prevent gas from filling the pore, reduce the volume error, and on the other hand, because the gap between the valve hole plug and the pore is very small, the heat exchange of the gas and the metal module can be enhanced.
The movable disc is fixedly connected with the sealing cover through a counter bore screw, the counter bore screw firstly passes through a middle opening of the movable disc from top to bottom, then passes through a middle opening of the spinning fastening cover, and finally is matched and screwed with the internal thread of the sealing cover; the movable disc and the sealing cover are connected into a whole after being fastened by the counter bore screws and freely move up and down along the spinning fastening cover, when the hand disc inner cover and the spinning fastening cover are screwed in downwards along the fastening cover base, the lower groove of the hand disc inner cover can gradually touch the movable disc, the sealing cover and the sample cell sealing ring are pressed on the sample cavity sealing boss along with continuous movement of the hand disc inner cover, and the sample cell sealing ring is made of soft materials, so that the pressure is higher, and the sealing is tighter.
After the cover body and the cavity body are tightly sealed, a closed cavity defined by the pressure sensor, the air inlet valve outlet, the equalizing valve inlet and the cover body is a sample cavity; a closed cavity defined by the outlet of the pressure equalizing valve, the inlet of the air release valve and the sealing plug is a reference cavity; the sample cavity is communicated with an external helium gas source through an air inlet valve; the sample cavity is communicated with the reference cavity through a pressure equalizing valve; the reference chamber is vented to the outside atmosphere through a vent valve.
The method for applying the module specifically comprises the following steps:
s1: washing the cavity: opening an external helium gas bottle, adjusting the pressure to the required test pressure through a pressure reducing valve, enabling helium to enter a densimeter pore passage module from a gas inlet, opening a gas inlet valve to enable the helium to enter a sample cavity, opening a pressure equalizing valve to enable the helium to enter a reference cavity, closing the gas inlet valve, opening a gas release valve, partially discharging air in the sample cavity and the reference cavity into the atmosphere through a gas release port, and closing the gas release valve after delaying for 10-30 seconds to finish the step of washing the cavity for one time; repeating the step of washing the cavity for 6-20 times to achieve the aim of exhausting air in the sample cavity and the reference cavity; after the cavity washing is finished, closing the pressure equalizing valve;
s2: air release step: opening a deflation valve and a pressure equalizing valve to release helium in the sample cavity and the reference cavity, recording the pressure corresponding to the pressure sensor after the pressure is stable, and simultaneously recording the temperature of the densimeter pore passage module measured by the temperature sensing element as the back bottom pressure P0And background temperature T0Closing the air release valve and the pressure equalizing valve;
s3: air inlet step: opening an air inlet valve, delaying for 10-30 seconds, closing the air inlet valve, recording the pressure corresponding to the pressure sensor at the moment after the pressure is stable, and recording the temperature of a pore passage module of the densitometer measured by a temperature sensing element as the air inlet pressure P1And the intake air temperature T1；
S4: pressure equalizing step: opening the pressure equalizing valve, enabling helium to enter the reference cavity from the sample cavity, recording the pressure corresponding to the pressure sensor at the moment after the pressure is stable, and simultaneously recording the temperature of the densimeter pore passage module measured by the temperature sensing element as the pressure equalizing pressure P2And voltage equalizing temperature T2Closing the pressure equalizing valve;
s5: according to the obtained background pressure, background temperature, inlet pressure, inlet temperature, pressure equalizing pressure, pressure equalizing temperature and known reference cavity volume VrVolume V of sample cupcAnd the volume V of the sample chambertCalculating the volume of the sample in the sample cup according to a gas state equation, and calculating the density of the sample according to the mass of the sample measured before testing; when the sample is a dense material, the measured density is true density; when the sample has closed pores inside, the density measured is a pseudo density.
In S1, the chamber washing step is only applied when a new sample is loaded, and the chamber washing step is not required for a sample in a helium-sealed state.
The temperature sensing element is attached to the surface of the pore passage module of the densitometer, and the temperature measured by the temperature sensing element is regarded as the temperature of helium entering the pore passage module of the densitometer; weighing the mass of the sample cup, carrying out drying treatment on the sample for a solid sample, placing the sample in the sample cup to enable the upper surface of the sample to be lower than the upper edge of the sample cup, weighing the total mass of the sample cup and the sample, and calculating the weighed mass of the sample.
According to the method, the volume of a sample in a sample cup is calculated according to a gas state equation according to the background pressure, the background temperature, the air inlet pressure, the air inlet temperature, the pressure equalizing pressure, the pressure equalizing temperature, the volume of a reference cavity, the volume of a sample cup body and the volume of a sample cavity measured in the air outlet step, the air inlet step and the pressure equalizing step, and then the density of the sample can be calculated according to the mass of the sample measured before the test; when the sample is a dense material, the measured density is the true density, also known as the skeleton density; when the sample has closed pores inside, the density measured is the pseudo density, also known as the apparent density or apparent density. The pore integrated module can measure the density of both solid material and liquid material. The method is characterized in that a slender pore passage corresponding to an inlet of an air inlet valve, a slender pore passage corresponding to an outlet of the air inlet valve, a slender pore passage corresponding to an inlet of a pressure equalizing valve, a slender pore passage corresponding to an outlet of the pressure equalizing valve, a metal material slender rod or a sintered porous slender rod with good heat conductivity are placed in the slender pore passage corresponding to an inlet of a vent valve and the slender pore passage corresponding to an outlet of the vent valve, the slender rod can be made of silver or red copper materials, the slender rod is not placed or other material slender rods are placed to only play a role in filling clearance volume, the effect on temperature uniformity of helium is small, the metal material slender rod and the sintered porous slender rod are preferably filled, the slender rod is made of other materials, and the worst is that any plug column is not filled. For the filled metal thin rod, silver with good thermal conductivity is preferred, and then red copper, and at worst aluminum, is preferred.
The density testing process can be continuously carried out according to the sequence of the air inlet step, the pressure equalizing step and the air outlet step, or can be continuously carried out according to the sequence of the air outlet step, the air inlet step and the pressure equalizing step, and the arrangement sequence of the air outlet step, the air inlet step and the pressure equalizing step is preferably selected.
The technical scheme of the invention has the following beneficial effects:
in the scheme, the pore passages with different diameters and depths are drilled on the density instrument pore passage module, and the helium is fully contacted with the metal density instrument pore passage module and the valve plug column which is filled in the elongated pore passage corresponding to the inlet of the air inlet valve and the elongated pore passage corresponding to the outlet of the air inlet valve and has good heat conduction, so that the heat exchange process from the outside to the inside of the density instrument pore passage module is completed; the densimeter pore module is made of metal materials, has high heat transfer speed and is a heat equalizing body, so that each pore, the sample cavity and the reference cavity are ensured to be positioned in the same constant temperature field; because the valve hole plug columns are filled in the pore channels, the clearance volume is reduced to the maximum extent, the proportion of the measured object volume is improved, and the measurement resolution and accuracy are improved; all solenoid valves are plate-type solenoid valves, leak gas a little, and gas tightness is strong to can realize automation and intellectuality.
Drawings
FIG. 1 is a schematic structural diagram of a module of the present invention;
FIG. 2 is a schematic view of a module cover according to the present invention;
FIG. 3 is a front view of a densitometer pore module of the present invention;
fig. 4 is a rear view of a densitometer pore module of the present invention.
Wherein: 1-hand plate outer cover, 2-inner cover screw, 3-hand plate inner cover, 4-movable disc, 5-spinning fastening cover, 6-sealing cover, 7-sample cup, 8-fastening cover base, 9-sample cell sealing ring, 10-base screw, 11-pressure sensor, 12-sensor fastening screw, 13-air inlet valve, 14-pressure equalizing valve, 15-air release valve, 16-valve plug column, 17-valve fastening screw hole, 18-plug fastening screw hole, 19-sealing plug, 20-plug fastening screw, 21-densimeter pore passage module, 22-pressure sensor hole, 23-air inlet, 24-air inlet valve inlet, 25-air inlet valve outlet, 26-sample cavity, 27-pressure equalizing valve inlet, 28-pressure equalizing valve outlet, 29-reference chamber, 30-air release valve inlet, 31-air release valve outlet, 32-air release port and 33-sample chamber sealing boss.
Detailed Description
In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
The invention provides a pore channel integrated module and a pore channel integrated method for measuring material density based on a gas displacement method.
As shown in fig. 1, the module comprises a cover body, a cavity body and a sample cup 7,
wherein, as shown in fig. 2, the cover body comprises a hand plate outer cover 1, an inner cover screw 2, a hand plate inner cover 3, a movable disc 4, a spinning fastening cover 5, a sealing cover 6, a fastening cover base 8, a sample cell sealing ring 9 and a base screw 10, the hand plate outer cover 1 is connected with the hand plate inner cover 3 through clearance fit, the hand plate outer cover 1 drives the hand plate inner cover 3 to rotate through friction force, after the hand plate inner cover 3 stops rotating, the hand plate outer cover 1 can still rotate freely, the friction force between the hand plate outer cover 1 and the hand plate inner cover 3 is controlled by the clamping force of fingers of an operator, the hand plate inner cover 3 is connected and fastened with the spinning fastening cover 5 through the inner cover screw 2, the movable disc 4 is arranged on the spinning fastening cover 5, the sealing cover 6 is connected below the spinning fastening cover 5, the sealing cover 6 covers the sample cup 7, the sample cup 7 is arranged in the cavity body, the fastening cover base 8 is fastened and connected with a densimeter pore passage module 21 through four base screws 10, when the outer hand disc cover 1 is rotated, the outer hand disc cover 1 drives the inner hand disc cover 3 to rotate through friction force, the inner hand disc cover 3 drives the spinning fastening cover 5 to rotate, the external thread of the spinning fastening cover 5 is screwed into the internal thread of the fastening cover base 8 until the sample cell sealing ring 9 on the sealing cover 6 presses the sample cavity sealing boss 33 to form sealing; the movable disc 4 is fixedly connected with the sealing cover 6 through a counter bore screw, the counter bore screw firstly penetrates through a middle hole of the movable disc 4 from top to bottom, then penetrates through a middle hole of the spinning fastening cover 5, and finally is matched and screwed with the internal thread of the sealing cover 6; the movable disc 4 and the sealing cover 6 are connected into a whole after being fastened by counter bore screws, and can freely move up and down along the spinning fastening cover 5, when the hand plate inner cover 3 and the spinning fastening cover 5 are screwed downwards along the fastening cover base 8, the lower groove of the hand plate inner cover 3 can gradually touch the movable disc 4, along with the continuous downward movement of the hand plate inner cover 3, the movable disc 4, the sealing cover 6 and the sample pool sealing ring 9 are tightly pressed on the sample cavity sealing boss 33, and the pressure is higher because the sample pool sealing ring 9 is made of soft materials, so the sealing is tighter.
The cavity body comprises a densimeter pore passage module 21, a pressure sensor 11, sensor fastening screws 12, a valve hole plug column 16, a sealing plug 19, plug fastening screws 20, an air inlet valve 13, a pressure equalizing valve 14 and a release valve 15, wherein the three plug fastening screws 20 are screwed into the corresponding plug fastening screw holes 18, the sealing plug 19 is fastened at a sealing position through the edges of the three plug fastening screws 20, the pressure sensor 11 is fastened in a pressure sensor hole 22 by the three sensor fastening screws 12 in the same manner as the sealing plug 19, and the air inlet valve 13, the pressure equalizing valve 14 and the release valve 15 are respectively fastened in the respective valve fastening screw holes 17 by four screws. When the upper cover body and the cavity body are tightly sealed, a closed cavity enclosed by the pressure sensor 11, the air inlet valve outlet 25, the pressure equalizing valve inlet 27 and the upper cover body is a sample cavity 26; a closed cavity defined by the pressure equalizing valve outlet 28, the deflation valve inlet 30 and the sealing plug 19 is a reference cavity 29; the sample cavity 26 is communicated with an external helium gas source through an air inlet valve 13; the sample chamber 26 communicates with the reference chamber 29 through the pressure equalizing valve 14; the reference chamber 29 is open to the outside atmosphere through the purge valve 15; as shown in fig. 3 and 4, the inlet 24 of the air inlet valve corresponds to a slender tunnel, the outlet 25 of the air inlet valve corresponds to a slender tunnel, the inlet 27 of the pressure equalizing valve corresponds to a slender tunnel, the outlet 28 of the pressure equalizing valve corresponds to a slender tunnel, the inlet 30 of the deflation valve corresponds to a slender tunnel, and the outlet 31 of the deflation valve corresponds to a slender tunnel, and metal slender rods with good heat conduction are placed in the slender tunnel, and the gap between the slender rods and the corresponding tunnel is less than 0.2 mm.
When the density of the material is measured, an upper temperature sensing element is attached to the surface of the densitometer pore passage module 21, and the measured temperature is taken as the temperature of helium entering the densitometer pore passage module 21; weigh the mass m of the sample cup 7cFor solid samples, the sample after drying treatment is placed in the sample cup 7 so that the upper surface of the sample is lower than the upper edge of the sample cup 7, and the sample cup 7 and the total mass m of the sample are weighedtCalculating the weighed sample mass ms＝mt-mc(ii) a The measuring step comprises a cavity washing step, a gas discharging step, a gas inlet step and a pressure equalizing step.
In the cavity washing step, an external helium gas bottle is opened, the pressure is adjusted to the required test pressure through a pressure reducing valve, helium enters the densimeter pore passage module 21 from the gas inlet 23, the gas inlet valve 13 is opened, the helium enters the sample cavity 26, the pressure equalizing valve 14 is opened, the helium enters the reference cavity 29, the gas inlet valve 13 is closed, the gas release valve 15 is opened, air in the sample cavity 26 and the reference cavity 29 is partially discharged into the atmosphere through the gas release port 32, the gas release valve 15 is closed after 10-30 seconds of delay, and the cavity washing step is completed; repeating the cavity washing step for 6-20 times to achieve the purpose of exhausting air in the sample cavity 26 and the reference cavity 29; the cavity washing step is only applied when a new sample is loaded, and the cavity washing step is not needed for the sample in a helium environment sealing state; after the cavity washing is finished, closing the pressure equalizing valve 14;
in the air release step, the air release valve 15 and the pressure equalizing valve 14 are opened to release helium in the sample cavity 26 and the reference cavity 29, after the pressure is stabilized, the pressure corresponding to the pressure sensor 11 at the moment is recorded, and the temperature of the densitometer pore module 21 measured by the temperature sensing element is recorded as the background pressure P0And background temperature T0(ii) a Closing the air relief valve 15 and the pressure equalizing valve 14;
in the air inlet step, the air inlet valve 13 is opened, the time is delayed for 10-30 seconds, the air inlet valve 13 is closed, after the pressure is stable, the pressure corresponding to the pressure sensor 11 at the moment is recorded, and the temperature of the densitometer pore passage module 21 measured by the temperature sensing element is recorded and used as the air inlet pressure P1And the intake air temperature T1；
In the pressure equalizing step, the pressure equalizing valve 14 is opened, helium enters the reference cavity 29 from the sample cavity 26, after the pressure is stabilized, the pressure corresponding to the pressure sensor 11 at the moment is recorded, and the temperature of the densitometer pore passage module 21 measured by the temperature sensing element is recorded as the pressure equalizing pressure P2And voltage equalizing temperature T2Closing the pressure equalizing valve 14;
the back pressure P measured according to the air discharging step, the air inlet step and the pressure equalizing step0Back bottom temperature T0Intake pressure P1Intake air temperature T1Pressure equalizing pressure P2Pressure equalizing temperature T2Reference cavity volume VrSample cup 7 volume VcAnd the volume V of the sample chambertCalculating the volume V of the sample chamber minus the sample cup according to the gas state equationcAnd the sample volume VsAfter the remaining volume Vg。
According to the volume V of the sample chambertAnd the volume V of the sample cupcCan be calculated to obtainVolume V of the sample in the sample cups＝Vt-Vc-VgAnd then according to the mass m of the sample measured before the testsThe density rho of the measured sample can be calculateds＝ms/Vs(ii) a When the sample is a dense material, the measured density is the true density, also known as the skeleton density; when the sample has closed pores inside, the density measured is the pseudo density, also known as the apparent density or apparent density. The pore integrated module can measure the density of both solid material and liquid material. The method is characterized in that a slender pore passage is arranged at the inlet of an air inlet valve, a slender pore passage is arranged at the outlet of the air inlet valve, a slender pore passage is arranged at the inlet of a pressure equalizing valve, a slender pore passage is arranged at the inlet of the pressure equalizing valve, a metal material slender rod or a sintered porous slender rod with good heat conductivity is arranged in the slender pore passage corresponding to the outlet of the air relief valve, the slender rod can be made of silver and red copper materials, the slender rod is not arranged or other material slender rods are arranged to only play a role in filling clearance volume, the effect on temperature uniformity of helium is small, the metal material slender rod and the sintered porous slender rod are preferably filled, the slender rod is made of other materials, and the worst is that any plug column is not filled. For the filled metal thin rod, silver with good thermal conductivity is preferred, and then red copper, and at worst aluminum, is preferred.
The density testing process can be continuously carried out according to the sequence of the air inlet step, the pressure equalizing step and the air outlet step, or can be continuously carried out according to the sequence of the air outlet step, the air inlet step and the pressure equalizing step, and the arrangement sequence of the air outlet step, the air inlet step and the pressure equalizing step is preferably selected.
The following description is given with reference to specific examples.
Example 1
The embodiment of the invention measures the true density of the quartz sand.
An electronic balance with the full measuring range of 120g and the minimum graduation of 0.1mg is selected to weigh the mass m of the sample cupc1.2766g, the dehydrated and dried quartz sand was added to the sample cup, and the total mass m of the sample cup and the quartz sand was measuredt12.0038g, the sample quartz sand mass m is measuredsComprises the following steps:
ms＝mt–mc＝12.0038–1.2766＝10.7272g
the method comprises the following steps that a helium gas cylinder with the volume of 10L is used, the purity is 99.99%, the helium gas cylinder is connected with a copper bipolar pressure reducing valve, the pressure is adjusted to be 0.06MPa gauge pressure through the bipolar pressure reducing valve, an outlet of the bipolar pressure reducing valve is connected with an external pipeline with the outer diameter of 6mm through a clamping sleeve connector, the external pipeline is connected with a testing instrument through a quick connector, and helium enters a pore passage integrated module; reference cavity volume Vr4.3743mL, sample Cavity volume Vt11.8131mL, sample cup volume Vc0.4598mL, then Vt-Vc11.3533 mL. A Pt100 thermal resistor is attached to the surface of the pore module of the densitometer to serve as a temperature sensing element.
The pore passage of the densimeter is cleaned for 8 times through the cavity cleaning step, the formal test process is carried out, the test is carried out according to the sequence of the air discharging step, the air inlet step and the pressure equalizing step, and the obtained results are shown in the following table:
TABLE 1 Quartz Sand test results data sheet
Taking the data of the 9 th measurement process as an example, all the pressures in table 1 are absolute pressures measured by the pressure sensors, and the calculation process is as follows:
T023.91 ℃ and 273.15+ 23.91K (calculated as the kelvin temperature) of 297.06K;
T123.94 ℃, and 273.15+23.94 as converted into 297.09K;
T223.93 ℃, and 273.15+ 23.93-297.08K in conversion of Kelvin;
sample cavity minus sample cup volume VcAnd the sample volume VsAfter the remaining volume VgComprises the following steps:
the volume V of the samplesComprises the following steps:
Vs＝Vt-Vc-Vg＝11.8131–0.4598–7.2821＝4.0712mL
density of sample ρsComprises the following steps:
ρs＝ms/Vs＝10.7272/4.0712＝2.63487g/mL
repeating the process for 10 times, calculating the results of 10 experiments, then averaging the results of 10 experiments, and finally measuring the density of the quartz sand as follows: 2.63466 g/mL.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (8)
1. A pore integrated module for measuring material density based on a gas displacement method is characterized in that: comprises a cover body, a cavity body and a sample cup (7),
wherein, the cover body comprises a hand dish outer cover (1), an inner cover screw (2), a hand dish inner cover (3), a movable disc (4), a spinning fastening cover (5), a sealing cover (6), a fastening cover base (8), a sample pool sealing ring (9) and a base screw (10), the hand dish outer cover (1) is connected with the hand dish inner cover (3) in a clearance fit way, the hand dish outer cover (1) drives the hand dish inner cover (3) to rotate through friction force, when the hand dish inner cover (3) stops rotating, the hand dish outer cover (1) can still freely rotate, the friction force between the hand dish outer cover (1) and the hand dish inner cover (3) is controlled by the clamping force of fingers of an operator, the hand dish inner cover (3) is connected with and fastened with the spinning fastening cover (5) through the inner cover screw (2), the movable disc (4) is arranged on the spinning fastening cover (5), the spinning fastening cover (5) is connected with the sealing cover (6) below the spinning fastening cover (5), the sealing cover (6) covers the sample cup (7), the sample cup (7) is arranged in the cavity body, the fastening cover base (8) is fixedly connected with the density meter pore channel module (21) through four base screws (10), when the hand disc outer cover (1) is rotated, the hand disc outer cover (1) drives the hand disc inner cover (3) to rotate through friction force, the hand disc inner cover (3) drives the spinning fastening cover (5) to rotate, the external thread of the spinning fastening cover (5) is screwed into the internal thread of the fastening cover base (8) until the sample pool sealing ring (9) on the sealing cover (6) presses the sample cavity sealing boss (33) to form sealing;
the cavity body comprises a densimeter pore passage module (21), a pressure sensor (11), sensor fastening screws (12), a valve hole plug column (16), a sealing plug (19), plug fastening screws (20), an air inlet valve (13), a pressure equalizing valve (14) and a deflation valve (15), the three plug fastening screws (20) are screwed into corresponding plug fastening screw holes (18), the sealing plug (19) is fastened at a sealing position through the edges of the three plug fastening screws (20), the pressure sensor (11) is fastened in a pressure sensor hole (22) by the three sensor fastening screws (12) in the same fixing mode of the sealing plug (19), and the air inlet valve (13), the pressure equalizing valve (14) and the deflation valve (15) are respectively fastened in the respective valve fastening screw holes (17) by four screws;
the density instrument pore module (21) is provided with a sample cavity sealing boss (33), the front surface is provided with an air inlet valve inlet (24), an air inlet valve outlet (25), a pressure equalizing valve inlet (27), a pressure equalizing valve outlet (28), a deflation valve inlet (30) and a deflation valve outlet (31), a slender pore channel is arranged in the density instrument pore module (21), the tail end of the air inlet valve inlet (24) corresponding to the slender pore channel is an air inlet (23), the air inlet (23) is opened behind the density instrument pore module (21), the tail end of the air inlet valve outlet (25) corresponding to the slender pore channel is connected to the slender pore channel connected with a pressure sensor hole (22), the tail end of the pressure equalizing valve inlet (27) corresponding to the slender pore channel is connected with a sample cavity (26), the tail end of the pressure equalizing valve outlet (28) corresponding to the slender pore channel is connected to the bottom of a reference cavity (29), the tail end of the deflation valve inlet (30) corresponding to the slender pore channel is connected to the upper part of the reference cavity (29), the air release valve outlet (31) is connected with an air release port (32) corresponding to the tail end of the long and thin pore channel, the air release port (32) is opened at the back of the density instrument pore channel module (21), fine metal rods with good heat conduction are placed in the long and thin pore channel, and the gap between each fine rod and the corresponding long and thin pore channel is smaller than 0.2 mm.
2. The pore channel integrated module for determining the density of a material based on a gas displacement method according to claim 1, wherein: the outer cover (1) of the hand dish is made of organic materials, and a groove is milled at the upper end of the outer cover and used for adhering marks; the excircle of the inner cover (3) of the handwheel is processed into a stripe shape, so that the friction force when the outer cover (1) of the handwheel is rotated is increased; the outer circle of the spinning fastening cover (5) is processed with external threads; an internal thread is processed on the inner circle of the fastening cover base (8); the sealing plug (19) comprises an O-shaped sealing ring; the pressure sensor (11) itself has an O-ring.
3. The pore channel integrated module for determining material density based on gas displacement method according to claim 1, wherein: the sample to be measured in the sample cup (7) is a solid material or a liquid material.
4. The pore channel integrated module for determining material density based on gas displacement method according to claim 1, wherein: the movable disc (4) is fixedly connected with the sealing cover (6) through a counter bore screw, the counter bore screw firstly passes through a middle opening of the movable disc (4) from top to bottom, then passes through a middle opening of the spinning fastening cover (5), and finally is matched and screwed with the internal thread of the sealing cover (6); activity disc (4) are even as an organic whole after sealed lid (6) are fastened by counter bore screw, along spinning fastening lid (5) upper and lower free movement, when hand dish inner cup (3) and spinning fastening lid (5) along fastening lid base (8) precession downwards, the lower part recess of hand dish inner cup (3) can touch activity disc (4) gradually, along with constantly moving down of hand dish inner cup (3), activity disc (4), sealed lid (6) and sample cell sealing washer (9) are compressed tightly on sample chamber seals boss (33), because sample cell sealing washer (9) are soft materials, pressure is big more, then sealed tighter.
5. The pore channel integrated module for determining material density based on gas displacement method according to claim 1, wherein: after the cover body and the cavity body are tightly sealed, a closed cavity enclosed by the pressure sensor (11), the air inlet valve outlet (25), the pressure equalizing valve inlet (27) and the cover body is a sample cavity (26); a closed cavity surrounded by the pressure equalizing valve outlet (28), the air relief valve inlet (30) and the sealing plug (19) is a reference cavity (29); the sample cavity (26) is communicated with an external helium gas source through an air inlet valve (13); the sample cavity (26) is communicated with the reference cavity (29) through a pressure equalizing valve (14); the reference chamber (29) is vented to the outside atmosphere through a vent valve (15).
6. The method for determining the pore channel integrated module of the material density based on the gas displacement method as claimed in claim 1, is characterized in that: the method comprises the following steps:
s1: washing the cavity: opening an external helium gas cylinder, adjusting the pressure to the required test pressure through a pressure reducing valve, enabling helium to enter a densimeter pore passage module (21) from a gas inlet (23), opening a gas inlet valve (13) to enable the helium to enter a sample cavity (26), opening a pressure equalizing valve (14), enabling the helium to enter a reference cavity (29), closing the gas inlet valve (13), opening a gas release valve (15), partially discharging the helium in the sample cavity (26) and the reference cavity (29) into the atmosphere through a gas release port (32), and closing the gas release valve (15) after delaying for 10-30 seconds to finish a cavity washing step; repeating the cavity washing step for 6-20 times to achieve the purpose of exhausting air in the sample cavity (26) and the reference cavity (29); after the cavity washing is finished, closing the pressure equalizing valve (14);
s2: air release step: opening a deflation valve (15) and a pressure equalizing valve (14), releasing helium in the sample cavity (26) and the reference cavity (29), recording the pressure corresponding to the pressure sensor (11) at the moment after the pressure is stable, simultaneously recording the temperature of a density instrument pore channel module (21) measured by a temperature sensing element as the background pressure and the background temperature, and closing the deflation valve (15) and the pressure equalizing valve (14);
s3: air inlet step: opening an air inlet valve (13), delaying for 10-30 seconds, closing the air inlet valve (13), recording the pressure corresponding to the pressure sensor (11) at the moment after the pressure is stable, and recording the temperature of a densitometer pore passage module (21) measured by a temperature sensing element as the air inlet pressure and the air inlet temperature;
s4: pressure equalizing step: opening a pressure equalizing valve (14), enabling helium to enter a reference cavity (29) from a sample cavity (26), recording the pressure corresponding to the pressure sensor (11) at the moment after the pressure is stable, simultaneously recording the temperature of a densimeter pore passage module (21) measured by a temperature sensing element as the pressure equalizing pressure and the pressure equalizing temperature, and closing the pressure equalizing valve (14);
s5: calculating the volume of the sample in the sample cup (7) according to the gas state equation according to the obtained background pressure, background temperature, air inlet pressure, air inlet temperature, pressure equalizing pressure and pressure equalizing temperature, the known reference cavity volume, sample cup volume and sample cavity volume, and calculating the density of the sample according to the mass of the sample measured before testing; when the sample is a dense material, the measured density is true density; when the sample has closed pores inside, the density measured is a pseudo density.
7. The method of claim 6, wherein: the step of washing the cavity in the S1 is only applied when a new sample is loaded, and the step of washing the cavity is not needed for the sample in a helium environment sealing state.
8. The method of claim 6, wherein: the temperature sensing element is attached to the surface of the density instrument pore passage module (21), and the temperature measured by the temperature sensing element is regarded as the temperature of helium entering the density instrument pore passage module (21); weighing the mass of the sample cup (7), firstly drying the sample for a solid sample, then placing the sample in the sample cup (7), weighing the total mass of the sample cup (7) and the solid sample, and calculating the weighed mass of the solid sample, wherein the upper surface of the measured solid sample is lower than the upper edge of the sample cup (7); and for the liquid sample, placing the liquid sample in the sample cup (7), wherein the upper surface of the measured liquid sample is lower than the upper edge of the sample cup (7), weighing the total mass of the sample cup (7) and the liquid sample, and calculating the weighed mass of the liquid sample.
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