CN114136837A - Volumetric method constant-voltage tester and voltage control method - Google Patents
Volumetric method constant-voltage tester and voltage control method Download PDFInfo
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Abstract
The application relates to a volumetric method constant pressure tester and a pressure control method, which relate to the field of physical adsorption instruments and equipment for specific surface area and aperture test, gas adsorption, vapor adsorption and the like, and comprise a reference cavity; an adsorption cavity for containing an adsorption material; the vacuum assembly is used for extracting gas in the reference cavity and the adsorption cavity; the gas source assembly is used for feeding gas to be adsorbed into the reference cavity; a first pressure sensor that measures a pressure in the reference chamber; a second pressure sensor for measuring the pressure in the adsorption chamber; the pressure servo valve is used for communicating or closing the reference cavity and the adsorption cavity; and the control system receives the data measured by the second pressure sensor and controls the opening or closing state of the pressure servo valve. This application has the effect of using the tester to adsorb test and desorption test.
Description
Technical Field
The application relates to the field of physical adsorption instruments and equipment for testing specific surface area and aperture, gas adsorption, vapor adsorption and the like, in particular to a volumetric method constant-pressure tester.
Background
For the test evaluation of the specific surface area, pore volume and pore diameter, gas adsorption, vapor adsorption and other performances of the adsorption materials such as porous materials, catalysts and the like, a physical adsorption method is mainly adopted, and an instrument adopting the method is called a physical adsorption instrument. The main principle of the physical adsorption instrument is a static capacity method, and the method is to load an adsorbent sample into an adsorption cavity with a certain volume and carry out quantification according to a gas state equation. At present, the existing volumetric method physical adsorption instrument at home and abroad is characterized in that a reference cavity with a known volume and containing a certain pressure adsorbate gas is communicated with an adsorption cavity containing an adsorbent sample to be detected, and then the adsorption quantity of the adsorbent sample to the adsorbate gas at a certain pressure point is obtained according to the pressure change in the total volume of the adsorption cavity and the reference cavity before and after adsorption, otherwise, the desorption quantity can also be obtained. The principle can obtain the adsorption capacity of the adsorbent sample at different pressure points under a certain temperature, namely an adsorption isotherm.
The adsorption process and desorption process of the existing volumetric method physical adsorption instrument based on the principle at home and abroad are described as follows.
In the adsorption test process, a certain amount of gas is put into the reference cavity, the reference cavity is communicated with the adsorption cavity, so that the pressure in the adsorption cavity is increased, and the adsorbate gas is adsorbed on the surface of the sample and the pore passage of the sample at the higher pressure simultaneously, so that the pressure in the adsorption cavity and the pressure in the reference cavity are gradually reduced; the adsorption equilibrium of the adsorbate gas is gradually achieved along with the diffusion of the adsorbate gas into the pore channel, in the process that the pressure in the adsorption cavity is gradually reduced, the adsorbate gas adsorbed on the surface of the adsorbent sample under high pressure can be desorbed along with the reduction of the pressure in the adsorption cavity, the desorbed adsorbate gas is used for compensating for the adsorbate required in the pore channel, and finally, after the adsorption equilibrium in the sample pore channel is achieved, the surface of the sample is also in desorption equilibrium, and the pressure tends to be stable, so that the adsorption equilibrium state of the adsorbent sample is achieved. And obtaining the adsorption quantity of the adsorbent sample to the adsorbate gas in the adsorption process according to the pressure reduction quantity of the adsorption cavity and the reference cavity before and after adsorption. It can be seen from the process that the pressure variation trend of the adsorption cavity is 'greatly increased first and then slowly decreased' in the adsorption process.
In the desorption test process, the pressure of the reference cavity is lower than that of the adsorption cavity, after the connection, the gas in the adsorption cavity is quantitatively transferred to the reference cavity, so that the pressure in the adsorption cavity is greatly reduced, and the surface of the sample and the pore channel of the sample are simultaneously desorbed under the lower pressure, so that the pressure in the adsorption cavity is gradually increased; along with the gradual desorption balance of the adsorbate gas from the inside of the pore channel, in the process that the pressure in the adsorption cavity is gradually increased, the adsorbate gas desorbed on the surface of a sample in the adsorption cavity under lower pressure can generate an adsorption phenomenon along with the increase of the pressure, the adsorbed adsorbate gas comes from the adsorbate desorbed from the pore channel, finally, after the desorption balance in the sample pore channel, the surface of the sample is also in adsorption balance, the pressure tends to be stable, and thus, the desorption balance state of the adsorbent sample is achieved. And obtaining the adsorption quantity of the adsorbent sample to the adsorbate gas in the desorption process according to the pressure increase of the adsorption cavity before and after desorption. It can be seen from the process that in the desorption process, the pressure change trend of the adsorption cavity is 'firstly greatly reduced and then slowly increased'.
From the above description, it can be seen that, when the traditional physical adsorption apparatus is used for testing the adsorption amount in the adsorption process and the desorption process, the pressure of the adsorbate gas in the adsorption cavity is greatly changed, and the "constant pressure" physical adsorption under a certain pressure cannot be realized.
In view of the above-mentioned related technologies, the inventor believes that the pressure stabilizing valve in the prior art can only control the gas flow direction to flow from the inlet to the outlet, cannot realize the gas reverse flow control, and can only perform the constant pressure adsorption test.
Disclosure of Invention
In order to use the tester to adsorb test and desorption test, this application provides a volumetric method constant voltage tester and accuse pressure method.
First aspect, the application provides a volumetric method constant voltage tester, adopts following technical scheme:
a constant voltage tester by volumetric method comprises:
a reference cavity;
an adsorption cavity for containing an adsorption material;
the vacuum assembly is used for extracting gas in the reference cavity and the adsorption cavity;
the gas source assembly is used for feeding gas to be adsorbed into the reference cavity;
a first pressure sensor that measures a pressure in the reference chamber;
a second pressure sensor for measuring the pressure in the adsorption chamber;
the pressure servo valve is used for communicating or isolating the reference cavity and the adsorption cavity;
the control system receives the data measured by the second pressure sensor and controls the opening or closing state of the pressure servo valve;
in the early stage of the adsorption test, when the pressure value measured by the first pressure sensor is equal to the set adsorption reference pressure value, the gas source assembly stops feeding gas into the reference cavity; continuing the adsorption test, and controlling the pressure servo valve to open by the control system when the pressure value measured by the second pressure sensor is smaller than the set adsorption test pressure value;
in the early stage of the desorption test, when the pressure value measured by the first pressure sensor is equal to the set desorption reference vacuum pressure value, the vacuum assembly stops extracting gas in the reference cavity; and continuing the desorption test, and controlling the pressure servo valve to open by the control system when the pressure value measured by the second pressure sensor is greater than the set adsorption test pressure value.
By adopting the technical scheme, the adsorption material is placed in the adsorption cavity, and the tester is assembled;
an adsorption process: the vacuum assembly extracts gas in the reference cavity and the adsorption cavity to enable the reference cavity and the adsorption cavity to reach set vacuum degrees; the control system controls the pressure servo valve to close, the gas source assembly sends gas into the reference cavity, the first pressure sensor detects the pressure in the reference cavity, and when the pressure in the reference cavity reaches the adsorption reference pressure value, the control system controls the gas source assembly to close;
the control system controls the pressure servo valve to be opened to enable gas in the reference cavity to flow into the adsorption cavity, the control system controls the pressure servo valve to be closed after the pressure in the adsorption cavity reaches a set adsorption test pressure value, at the moment, the adsorption material adsorbs the gas in the adsorption cavity, the pressure in the adsorption cavity is reduced, the control system compares data obtained through measurement of the second pressure sensor with the adsorption test pressure value, when the data is smaller than target pressure, the pressure servo valve is opened to enable the gas in the reference cavity to enter the adsorption cavity again, and when the pressure value measured and monitored by the second pressure sensor reaches the adsorption test pressure value, the controller controls the pressure servo valve to be closed until the pressure in the reference cavity monitored by the second pressure sensor is equal to the adsorption test pressure value and does not change any more, and the adsorption process of the adsorption material can be judged to be completed;
a desorption process: when the adsorption is finished, the pressure servo valve is in a closed state, after the adsorption is finished, the desorption test can be continuously carried out by using the tester in the scheme, the vacuum component extracts gas in the reference cavity, so that the reference cavity reaches a desorption reference vacuum pressure value corresponding to the set vacuum degree, and the vacuum component is closed;
the control system controls the pressure servo valve to be opened, when the control system judges that the pressure monitored by the second pressure sensor in the adsorption cavity is smaller than a set adsorption test pressure value, the control system controls the pressure servo valve to be closed, adsorbed gas on the adsorption material is desorbed, the pressure in the adsorption cavity is increased, when the control system judges that the pressure monitored by the second pressure sensor in the adsorption cavity is smaller than the set adsorption test pressure value, the control system controls the pressure servo valve to be closed again, and when the control system judges that the pressure monitored by the second pressure sensor in the adsorption cavity is equal to the set adsorption test pressure value and is not changed any more, the adsorption material can be judged to complete the desorption process.
Preferably, the pressure servo valve is a proportional valve with an adjustable opening degree.
By adopting the technical scheme, the communication state between the reference cavity and the adsorption cavity can be controlled by controlling the opening degree of the proportional valve, and the smaller the opening degree of the proportional valve is, the slower the gas circulation speed is under the same pressure difference; when the flow speed of the gas between the reference cavity and the adsorption cavity needs to be increased, the opening of the proportional valve is increased, and when the flow speed of the gas between the reference cavity and the adsorption cavity needs to be reduced, the opening of the proportional valve is reduced.
Preferably, the pressure servo valve is a stop valve with fixed opening and adjustable single opening time; the control system controls the pressure servo valve to open for a certain time and then close.
Through adopting above-mentioned technical scheme, through the single open time of control stop valve, can control the reference chamber and adsorb the intercommunication state between the chamber, when needs improve the circulation speed of gaseous between reference chamber and the absorption chamber, the open time of stop valve in the extension unit interval, when needs reduce the circulation speed of gaseous between reference chamber and the absorption chamber, the open time of stop valve until closing the stop valve completely in the shortening unit interval.
Preferably, the device further comprises a third stop valve, two ends of the third stop valve are respectively communicated with the reference cavity and the adsorption cavity, and the third stop valve is connected with the pressure servo valve in parallel.
By adopting the technical scheme, in the step of vacuumizing the reference cavity and the adsorption cavity during adsorption test, the control system controls the first stop valve and the pressure servo valve to be opened and controls the second stop valve and the third stop valve to be closed simultaneously;
because the opening of the pressure servo valve is smaller, the flowing speed of the gas entering the reference cavity from the adsorption cavity is relatively slow, so that the powder sample in the adsorption cavity can be effectively prevented from being pumped and flying into an instrument pipeline, and the pollution of a powder adsorption material to a valve and the pipeline can be effectively avoided;
through the pressure in the second pressure sensor monitoring adsorption cavity, when control system judges that the gas pressure in the adsorption cavity reduces to a certain value, control system control third stop valve opens, and the vacuum pump can be taken out residual gas in the adsorption cavity fast this moment, makes the adsorption cavity reach higher vacuum.
Preferably, the opening degree of the third cut-off valve is larger than the opening degree of the pressure servo valve.
Through adopting above-mentioned technical scheme, the back is opened to the third stop valve, can show the evacuation effect that improves the absorption chamber inner chamber, improves the evacuation degree in absorption chamber.
Preferably, the vacuum assembly comprises a vacuum pump and a first stop valve communicated with an air inlet of the vacuum pump, and the other end of the first stop valve is communicated with the reference cavity.
By adopting the technical scheme, when the vacuum pumping operation needs to be carried out on the reference cavity and the cavity communicated with the reference cavity, the first stop valve and the vacuum pump are opened, the vacuum degree in the reference cavity is judged through the first pressure sensor, and when the set vacuum degree is reached, the first stop valve and the vacuum pump are closed, so that the vacuum pumping operation of the vacuum assembly on the reference cavity and the cavity communicated with the reference cavity is completed.
Preferably, the opening degree of the pressure servo valve is smaller than the opening degree of the first cut valve.
Through adopting above-mentioned technical scheme, pressure servo valve aperture is little, is convenient for control benchmark chamber and adsorbs the fluid flow velocity between the chamber, and is more accurate to the pressure control who adsorbs the intracavity.
Preferably, the control system is respectively connected with the vacuum assembly, the air source assembly, the first pressure sensor, the second pressure sensor and the pressure servo valve through circuits.
By adopting the technical scheme, the control system is in circuit connection with other components of the measuring instrument, so that the control system can conveniently and quickly send or receive stable signals to other components.
In a second aspect, the present application provides a pressure control method, which adopts the following technical scheme:
a pressure control method is characterized in that a second pressure sensor monitors the pressure in an adsorption cavity in real time and transmits the pressure to a control system;
the control system controls the pressure servo valve to open, so that the fluid in the adsorption cavity flows in or out;
and when the second pressure sensor measures that the pressure in the adsorption cavity reaches a target value, the control system controls the pressure servo valve to be closed.
In summary, the present application includes at least one of the following beneficial technical effects:
putting the adsorbing material into an adsorbing cavity, and assembling the tester;
an adsorption process: the vacuum assembly extracts gas in the reference cavity and the adsorption cavity to enable the reference cavity and the adsorption cavity to reach set vacuum degrees; the control system controls the pressure servo valve to close, the gas source assembly sends gas into the reference cavity, the first pressure sensor detects the pressure in the reference cavity, and when the pressure in the reference cavity reaches the adsorption reference pressure value, the control system controls the gas source assembly to close;
the control system controls the pressure servo valve to be opened to enable gas in the reference cavity to flow into the adsorption cavity, the control system controls the pressure servo valve to be closed after the pressure in the adsorption cavity reaches a set adsorption test pressure value, at the moment, the adsorption material adsorbs the gas in the adsorption cavity, the pressure in the adsorption cavity is reduced, the control system compares data obtained through measurement of the second pressure sensor with the adsorption test pressure value, when the data is smaller than target pressure, the pressure servo valve is opened to enable the gas in the reference cavity to enter the adsorption cavity again, and when the pressure value measured and monitored by the second pressure sensor reaches the adsorption test pressure value, the controller controls the pressure servo valve to be closed until the pressure in the reference cavity monitored by the second pressure sensor is equal to the adsorption test pressure value and does not change any more, and the adsorption process of the adsorption material can be judged to be completed;
a desorption process: when the adsorption is finished, the pressure servo valve is in a closed state, after the adsorption is finished, the desorption test can be continuously carried out by using the tester in the scheme, the vacuum component extracts gas in the reference cavity, so that the reference cavity reaches a desorption reference vacuum pressure value corresponding to the set vacuum degree, and the vacuum component is closed;
the control system controls the pressure servo valve to be opened, when the control system judges that the pressure monitored by the second pressure sensor in the adsorption cavity is smaller than a set adsorption test pressure value, the control system controls the pressure servo valve to be closed, adsorbed gas on the adsorption material is desorbed, the pressure in the adsorption cavity is increased, when the control system judges that the pressure monitored by the second pressure sensor in the adsorption cavity is smaller than the set adsorption test pressure value, the control system controls the pressure servo valve to be closed again, and when the control system judges that the pressure monitored by the second pressure sensor in the adsorption cavity is equal to the set adsorption test pressure value and is not changed any more, the adsorption material can be judged to complete the desorption process.
Drawings
FIG. 1 is a schematic overall structure diagram of the first embodiment;
fig. 2 is a schematic view of the overall structure of the second embodiment.
Description of reference numerals: 1. a control system; 2. a first shut-off valve; 3. a vacuum pump; 4. a second stop valve; 5. a gas source; 6. a reference cavity; 7. a first pressure sensor; 8. a third stop valve; 9. a pressure servo valve; 10. a second pressure sensor; 11. an adsorption chamber.
Detailed Description
The present application is described in further detail below with reference to figures 1-2.
The embodiment of the application discloses a volumetric method constant-voltage tester and a pressure control method.
Example 1
Referring to fig. 1, a volumetric method constant pressure tester comprises a reference chamber 6 with a fixed inner chamber volume and an adsorption chamber 11 for storing adsorption powder; the vacuum component is used for vacuumizing the reference cavity 6, and the gas source component is used for feeding gas to be adsorbed into the reference cavity 6; a first pressure sensor 7 for measuring the pressure in the cavity of the reference cavity 6 and a second pressure sensor 10 for measuring the pressure in the cavity of the adsorption cavity 11; and the control system 1 controls the tester to automatically work.
The vacuum assembly comprises a vacuum pump 3 and a first stop valve 2, wherein the air inlet of the vacuum pump 3 is connected with one end of the first stop valve 2, and the end, far away from the vacuum pump 3, of the first stop valve 2 is connected with a reference cavity 6. When the reference cavity 6 and the cavity communicated with the reference cavity are required to be vacuumized, the first stop valve 2 and the vacuum pump 3 are opened, the vacuum degree in the reference cavity 6 is judged through the first pressure sensor 7, and when the set vacuum degree is reached, the first stop valve 2 and the vacuum pump 3 are closed.
The air supply assembly comprises an air supply 5 and a second stop valve 4, the air supply 5 is internally provided with a compressed gas with adsorption, the air supply 5 is connected with one end of the second stop valve 4, and one end of the second stop valve 4 far away from the air supply 5 is connected with the reference cavity 6. When the gas in the gas source 5 needs to be filled into the reference cavity 6, only the second stop valve 4 on the reference cavity 6 is opened, other valves arranged on the reference cavity 6 are closed, at the moment, the gas in the gas source 5 enters the reference cavity 6 through the second stop valve 4, the pressure in the reference cavity 6 is judged through the first pressure sensor 7, and when the set target pressure is reached, the second stop valve 4 is closed.
A pressure servo valve 9 is arranged between the reference cavity 6 and the adsorption cavity 11, one end of the pressure servo valve 9 is connected with the reference cavity 6, and the other end of the pressure servo valve is connected with the adsorption cavity 11. The pressure servo valve 9 is a proportional valve with an adjustable opening degree, in other embodiments, the pressure servo valve 9 is a stop valve with a fixed opening degree but an adjustable opening time, that is, the opening time of the stop valve per unit time, and the opening and closing times of the stop valve are hundreds of times per second. The pressure servo valve 9 and the second pressure sensor 10 work in a matching mode, the pressure in the adsorption cavity 11 is constant through pressure servo control, the control system 1 obtains pressure data in the adsorption cavity 11 measured by the second pressure sensor 10, and the control system 1 controls the opening degree of the pressure servo valve 9 through comparison with target data of the adsorption cavity 11.
The control system 1 is in control connection with the first stop valve 2, the second stop valve 4, the vacuum pump 3, the first pressure sensor 7, the second pressure sensor 10 and the vacuum pump 3 in a circuit mode. In another embodiment, the control system 1 is in wireless signal connection with the first stop valve 2, the second stop valve 4, the vacuum pump 3, the first pressure sensor 7, the second pressure sensor 10 and the vacuum pump 3.
The implementation principle of the constant-voltage tester adopting the volumetric method is as follows:
in the adsorption process, the working process of the cooperation of the pressure servo valve 9 and the second pressure sensor 10 is as follows:
and (3) vacuumizing: the control system 1 controls the second stop valve 4 to be closed, the first stop valve 2 and the pressure servo valve 9 to be opened, the reference cavity 6 is communicated with the adsorption cavity 11 at the moment, the control system 1 controls the vacuum pump 3 to be opened to vacuumize the reference cavity 6 and the adsorption cavity 11, the control system 1 obtains data measured by the first pressure sensor 7 and the second pressure sensor 10, and after the reference cavity 6 and the adsorption cavity 11 reach the set vacuum degree, the vacuum pump 3 and the first stop valve 2 are closed through the pressure servo valve 9.
Filling the reference cavity 6 with gas to be adsorbed: the control system 1 controls the second stop valve 4 to be opened, the air source 5 inflates the reference cavity 6, and the second stop valve 4 is closed after the air in the reference cavity 6 reaches the preset pressure. At this time, gas of a predetermined pressure is stored in the reference chamber 6, and the adsorption chamber 11 is in a vacuum state.
Air inlet step of the adsorption cavity 11: the second pressure sensor 10 monitors the pressure state in the adsorption cavity 11 in real time, the control system 1 controls the pressure servo valve 9 to be opened to enable the gas in the reference cavity 6 to enter the adsorption cavity 11, and when the pressure in the adsorption cavity 11 reaches a set value, the control system 1 controls the opening degree of the pressure servo valve 9 to enable the pressure servo valve 9 to be closed.
And (3) sample adsorption judgment: when the gas in the adsorption cavity 11 is adsorbed by the sample in the adsorption cavity 11, the pressure of the gas in the adsorption cavity 11 is reduced, the second pressure sensor 10 transmits a pressure signal to the control system 1, and the control system 1 compares the target pressure to judge that the pressure in the adsorption cavity 11 is reduced.
Repeating the air inlet step of the adsorption cavity 11: the control system 1 controls the pressure servo valve 9 to open so that the gas in the reference cavity 6 enters the adsorption cavity 11, when the pressure in the adsorption cavity 11 reaches a set value, the second pressure sensor 10 transmits the pressure signal to the control system 1, and the control system 1 controls the pressure servo valve 9 to close so as to realize that the gas pressure in the adsorption cavity 11 reaches the target pressure again.
Repeating the sample adsorption judging step: and repeating the cycle control until the sample in the adsorption cavity 11 is adsorbed and saturated, namely, the sample adsorption judging step: the gas pressure in the adsorption cavity 11 is kept unchanged, the second pressure sensor 10 transmits a pressure signal to the control system 1, the control system 1 compares the target pressure to judge that the adsorption of the sample is saturated, and the pressure servo valve 9 keeps a closed state.
After the adsorption process is completed, the desorption process test can be continued.
In the desorption process, the working process of the cooperation of the pressure servo valve 9 and the second pressure sensor 10 is as follows:
and (3) vacuumizing: the control system 1 controls the second stop valve 4 and the pressure servo valve 9 to be closed, the first stop valve 2 is opened, the control system 1 controls the vacuum pump 3 to be opened to vacuumize the reference cavity 6, the control system 1 obtains data measured by the first pressure sensor 7, and after the reference cavity 6 reaches a set vacuum degree, the vacuum pump 3 and the first stop valve 2 are closed.
Desorption and exhaust in the adsorption cavity 11: the control system 1 controls the pressure servo valve 9 to be opened, the gas in the adsorption cavity 11 flows into the reference cavity 6 until the pressure in the adsorption cavity 11 reaches the target pressure, and the control system 1 controls the pressure servo valve 9 to be closed.
A sample desorption judgment step: when the adsorbate gas is desorbed from the surface of the sample, the pressure data measured by the second pressure sensor 10 is sent to the control system 1, and the control system 1 compares the target pressure to judge that the pressure in the adsorption cavity 11 is increased again.
And repeating the desorption and exhaust steps in the adsorption cavity 11: the control system 1 controls the pressure servo valve 9 to be opened again, the gas in the adsorption cavity 11 flows into the reference cavity 6 until the pressure in the adsorption cavity 11 reaches the target pressure, and the control system 1 controls the pressure servo valve 9 to be closed.
And (3) repeating the sample desorption judging step, and repeatedly and circularly controlling the processes until the pressure in the adsorption cavity 11 is stable, namely the sample desorption judging step: the pressure data measured by the second pressure sensor 10 is sent to the control system 1, the control system 1 compares the target pressure, and judges that the pressure in the adsorption cavity 11 is kept unchanged, the desorption of the adsorbate gas from the surface of the sample is completed, and the pressure servo valve 9 is kept in a closed state.
The embodiment of the application also discloses a pressure control method.
A pressure control method comprises the following steps:
the second pressure sensor 10 monitors the pressure change in the adsorption cavity 11 in real time and transmits the change to the control system 1;
the control system 1 controls the opening state of the pressure servo valve 9 to realize the inflow or outflow of gas in the adsorption cavity 11;
when the pressure in the adsorption chamber 11 reaches a target value, the control system 1 controls the pressure servo valve 9 to close.
Example 2
Referring to fig. 2, the present embodiment is different from embodiment 1 in that the volumetric method constant pressure tester further includes a third cut-off valve 8, and the third cut-off valve 8 and the pressure servo valve 9 are connected in parallel, that is, both ends of the third cut-off valve 8 are respectively communicated with the reference chamber 6 and the adsorption chamber 11. The control system 1 controls the opening or closing of the third cut-off valve 8.
Preferably, the opening degree of the third stop valve 8 is greater than the pressure servo valve 9, i.e. the flow cross section of the gas after the third stop valve 8 is opened is greater than the flow cross section of the gas after the pressure servo valve 9 is fully opened.
During the adsorption test, in the step of vacuumizing the reference cavity 6 and the adsorption cavity 11, the control system 1 controls the vacuum pump 3 to start the vacuumizing operation on the reference cavity 6 and the adsorption cavity 11.
The control system 1 controls the first stop valve 2 and the pressure servo valve 9 to open, while controlling the second stop valve 4 and the third stop valve 8 to close.
Because the opening degree of the pressure servo valve 9 is small, the gas flowing speed entering the reference cavity 6 from the adsorption cavity 11 is relatively low, the powder sample in the adsorption cavity 11 can be effectively prevented from being pumped and flying to enter an instrument pipeline, and the pollution of the powder adsorption material to the valve and the pipeline can be effectively avoided.
The pressure in the adsorption cavity 11 is monitored through the second pressure sensor 10, when the control system 1 judges that the gas pressure in the adsorption cavity 11 is reduced to a certain value, the control system 1 controls the third stop valve 8 to be opened, and at the moment, the vacuum pump 3 can rapidly pump out the residual gas in the adsorption cavity 11, so that the adsorption cavity 11 reaches a higher vacuum degree.
The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.
Claims (9)
1. The utility model provides a constant voltage tester of volumetric method which characterized in that includes:
a reference cavity (6);
an adsorption chamber (11) for containing an adsorption material;
the vacuum assembly is used for extracting gas in the reference cavity (6) and the adsorption cavity (11);
the gas source assembly is used for feeding gas to be adsorbed into the reference cavity (6);
a first pressure sensor (7) measuring the pressure inside the reference chamber (6);
a second pressure sensor (10) that measures the pressure in the adsorption chamber (11);
a pressure servo valve (9) for communication or isolation between the reference chamber (6) and the adsorption chamber (11);
the control system (1) is used for receiving data measured by the second pressure sensor (10) and controlling the opening or closing state of the pressure servo valve (9);
in the early stage of the adsorption test, when the pressure value measured by the first pressure sensor (7) is equal to the set adsorption reference pressure value, the gas source assembly stops sending gas into the reference cavity; continuing the adsorption test, and when the pressure value measured by the second pressure sensor (10) is smaller than the set adsorption test pressure value, controlling the pressure servo valve (9) to be opened by the control system (1);
in the early stage of the desorption test, when the pressure value measured by the first pressure sensor (7) is equal to the set desorption reference vacuum pressure value, the vacuum assembly stops extracting gas in the reference cavity; and continuing the desorption test, and when the pressure value measured by the second pressure sensor (10) is greater than the set adsorption test pressure value, controlling the pressure servo valve (9) to be opened by the control system (1).
2. The volumetric method constant voltage tester according to claim 1, characterized in that: the pressure servo valve (9) is a proportional valve with an adjustable opening degree.
3. The volumetric method constant voltage tester according to claim 1, characterized in that: the pressure servo valve (9) is a stop valve with fixed opening and adjustable single opening time; the control system (1) controls the pressure servo valve (9) to be opened for a certain time and then closed.
4. The volumetric method constant-pressure tester according to any one of claims 1 to 3, characterized in that: the device is characterized by further comprising a third stop valve (8), wherein two ends of the third stop valve (8) are respectively communicated with the reference cavity (6) and the adsorption cavity (11), and the third stop valve (8) is connected with the pressure servo valve (9) in parallel.
5. The volumetric method constant voltage tester according to claim 4, characterized in that: the opening degree of the third stop valve (8) is greater than the opening degree of the pressure servo valve (9).
6. The volumetric method constant voltage tester according to any one of claims 1, 2, 3, and 5, wherein: the vacuum assembly comprises a vacuum pump (3) and a first stop valve (2) communicated with an air inlet of the vacuum pump (3), and the other end of the first stop valve (2) is communicated with a reference cavity (6).
7. The volumetric method constant voltage tester according to claim 6, characterized in that: the opening degree of the pressure servo valve (9) is smaller than the opening degree of the first stop valve (2).
8. The volumetric method constant voltage tester according to any one of claims 1, 2, 3, and 5, wherein: the control system (1) is respectively connected with the vacuum assembly, the air source assembly, the first pressure sensor (7), the second pressure sensor (10) and the pressure servo valve (9) through circuits.
9. A pressure control method for a volumetric constant pressure tester according to any one of claims 1 to 8, characterized in that: the second pressure sensor (10) monitors the pressure in the adsorption cavity (11) in real time and transmits the pressure to the control system (1);
the control system (1) controls the pressure servo valve (9) to be opened, so that the inflow or outflow of fluid in the adsorption cavity (11) is realized;
when the second pressure sensor (10) measures that the pressure in the adsorption cavity (11) reaches a target value, the control system (1) controls the pressure servo valve (9) to be closed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202111279568.8A CN114136837A (en) | 2021-10-28 | 2021-10-28 | Volumetric method constant-voltage tester and voltage control method |
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| CN202111279568.8A CN114136837A (en) | 2021-10-28 | 2021-10-28 | Volumetric method constant-voltage tester and voltage control method |
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| CN114136837A true CN114136837A (en) | 2022-03-04 |
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| CN202111279568.8A Pending CN114136837A (en) | 2021-10-28 | 2021-10-28 | Volumetric method constant-voltage tester and voltage control method |
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