An online volume measurement method based on molecular conductivity

Abstract

This invention relates to the field of vacuum measurement technology. A method for online volume measurement based on molecular conductance is disclosed, comprising: controlling a vacuum pump group to evacuate a standard volume chamber; controlling a gas source to fill the standard volume chamber with gas to achieve a first pressure; controlling the vacuum pump group to evacuate a vacuum conduction orifice; priming the standard volume chamber through the vacuum conduction orifice based on preset time intervals, determining the pressure in the standard volume chamber after each time interval as an intermediate pressure; determining the pressure in the standard volume chamber as a second pressure based on a preset duration; and determining the volume of the standard volume chamber based on the first pressure, second pressure, time interval, intermediate pressure, and conductance value of the vacuum conduction orifice. This application eliminates the need to load, unload, and send the standard volume chamber for inspection, enabling on-site volume measurement of standard volumes susceptible to external factors.

Description

Technical Field

[0001] This invention relates to the field of vacuum measurement technology, and in particular to an online volume measurement method based on molecular conductivity. Background Technology

[0002] Standard gas flow rates have wide applications in scientific research, production, and metrology, playing a crucial role in areas such as leak detection, leak rate calibration, pumping speed testing, ultra-high vacuum gauge calibration, special experiments, and process manufacturing. Currently, flow rates greater than 10... -2 Pa·m 3 Flow rate devices with a flow rate of / s are relatively mature, and there are many commercially available electrical products. However, for flow rates less than 10... -2 Pa·m 3 Standard gas flow rates in the field of metrology and testing are difficult to achieve due to the high sealing requirements of electronic components. Currently, flow rates of this magnitude are mainly provided through a standard volume of fixed size and a vacuum flow guide orifice.

[0003] As the foundation for flow rate measurement, standard volume parameters determine the accuracy of flow rate in the field of metrology and testing. However, in field use, drastic environmental changes can affect volume parameters. Generally, to ensure the accuracy of the provided flow rate, the standard volume needs to be calibrated regularly in a laboratory environment with constant temperature and humidity. However, in field environments with frequent temperature and humidity changes, when performing a large number of calibration tasks continuously, the flow meter needs to work continuously for long periods of time, making it impractical to repeatedly disassemble the standard volume and send it to a calibration laboratory for calibration.

[0004] Therefore, there is a need to provide a method for online volume measurement of standard volumes. Summary of the Invention

[0005] In view of this, the present invention provides an online volume measurement method based on molecular conductance.

[0006] Specifically, the following technical solutions are included: This application provides an online volume measurement method based on molecular flow conductance for online volume measurement of the standard volume chamber of a flow meter device. The flow meter device includes a standard volume chamber, a vacuum flow conductance orifice, a gas source, and a vacuum pump assembly. The vacuum flow conductance orifice, the gas source, and the vacuum pump assembly are respectively connected to the standard volume chamber, and the vacuum flow conductance orifice is connected to the vacuum pump assembly. The method includes: The vacuum pump unit is controlled to evacuate the standard volume chamber. The gas source is controlled to fill the standard volume chamber with gas, so that the pressure in the standard volume chamber is a first pressure; The vacuum pump unit is controlled to evacuate the vacuum flow guide orifice; Based on a preset time interval, air is drawn into the standard volume chamber through the vacuum flow guide orifice, and the pressure inside the standard volume chamber after each time interval is determined to be the intermediate pressure. The pressure inside the standard volume chamber is determined as the second pressure based on a preset duration. The volume of the standard volume chamber is determined based on the first pressure, the second pressure, the time interval, the intermediate pressure, and the conductivity value of the vacuum flow guide orifice.

[0007] For example, determining the volume of the standard volume chamber based on the first pressure, the second pressure, the time interval, the intermediate pressure, and the conductivity value of the vacuum flow guide orifice includes: The total gas flow rate is determined based on the time interval, the intermediate pressure, and the conductivity value of the vacuum flow guide orifice. Determine the total pressure difference based on the first pressure and the second pressure; The volume of the standard volume chamber is determined based on the ratio of the total gas flow rate to the total pressure difference.

[0008] For example, controlling the vacuum pump assembly to evacuate the standard volume chamber includes: The system controls the connection between the standard volume chamber and the vacuum pump group, the disconnection between the standard volume chamber and the gas source, the disconnection between the standard volume chamber and the vacuum flow guide orifice, and the disconnection between the vacuum flow guide orifice and the vacuum pump group. The vacuum pump unit is started to evacuate the standard volume chamber.

[0009] For example, controlling the gas source to fill the standard volume chamber with gas to make the pressure in the standard volume chamber a first pressure includes: The control system disconnects the standard volume chamber from the vacuum pump assembly, connects the standard volume chamber to the gas source, disconnects the standard volume chamber from the vacuum flow guide orifice, and disconnects the vacuum flow guide orifice from the vacuum pump assembly. The gas source is activated to fill the standard volume chamber with gas, so that the pressure in the standard volume chamber is the first pressure.

[0010] For example, controlling the vacuum pump assembly to evacuate the vacuum flow guide orifice includes: The control system disconnects the standard volume chamber from the vacuum pump assembly, disconnects the standard volume chamber from the gas source, disconnects the standard volume chamber from the vacuum flow guide orifice, and connects the vacuum flow guide orifice to the vacuum pump assembly. The vacuum pump unit is started to evacuate the vacuum flow guide orifice.

[0011] For example, based on a preset time interval, air is drawn into the standard volume chamber through the vacuum flow guide orifice, and the pressure inside the standard volume chamber after each time interval is determined to be the intermediate pressure, including: The control system disconnects the standard volume chamber from the vacuum pump assembly, disconnects the standard volume chamber from the gas source, connects the standard volume chamber to the vacuum flow guide orifice, and connects the vacuum flow guide orifice to the vacuum pump assembly. The vacuum pump unit is started to evacuate the standard volume chamber. Based on a preset time interval, the pressure inside the standard volume chamber after each time interval is determined as the intermediate pressure.

[0012] For example, determining the pressure within the standard volume chamber as the second pressure based on a preset duration includes: The control system disconnects the standard volume chamber from the vacuum pump assembly, the standard volume chamber from the gas source, the standard volume chamber from the vacuum flow guide orifice, and the vacuum flow guide orifice from the vacuum pump assembly. The pressure inside the standard volume chamber is determined as the second pressure during the preset duration.

[0013] For example, the number of intermediate pressures is greater than a preset number.

[0014] For example, the conductivity of the vacuum flow-guiding orifice is 10. -8 ~10 -9 Pa·m 3 / s.

[0015] For example, the volume of the standard volume chamber is smaller than a preset volume.

[0016] The beneficial effects of the technical solution provided by this invention include at least the following: This application couples the vacuum flow guide orifice, gas source, and vacuum pump assembly to the standard volume chamber, eliminating the need to install, remove, and send the standard volume chamber for testing. This allows for on-site measurement of the standard volume, which is susceptible to external factors, improving the working quality of the flow meter and maximizing its reliability and accuracy in field operations. This application can be used to measure the standard volume chamber inside flow meters that operate continuously for extended periods without the need for shutdown. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1This is a schematic diagram of a flow meter device for online volume measurement based on molecular conductance, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the flow structure of an online volume measurement method based on molecular conductivity according to an embodiment of the present invention.

[0019] The reference numerals in the figure are respectively: 1. Standard volume chamber; 2. Vacuum flow guide orifice; 3. Vacuum detection component; 4. Vacuum pump assembly; 5. Gas source; 6. First vacuum valve; 7. Second vacuum valve; 8. Third vacuum valve; 9. Fourth vacuum valve; 10. Fifth vacuum valve.

[0020] The accompanying drawings have illustrated specific embodiments of the invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Before providing a further detailed description of the embodiments of the present invention, the directional terms used in the embodiments of the present invention, such as "upper part," "lower part," and "side part," are used to refer to... Figure 1 The orientation shown is a reference and does not limit the scope of protection of this invention.

[0023] To make the technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0024] This embodiment provides a flow meter device based on molecular conductance for online volume measurement. The online volume measurement method based on molecular conductance is used to perform online volume measurement of the standard volume chamber 1 of the flow meter device. Figure 1 As shown, the flow meter device includes a standard volume chamber 1, a vacuum flow guide orifice 2, a gas source 5, and a vacuum pump assembly 4. The vacuum flow guide orifice 2, the gas source 5, and the vacuum pump assembly 4 are respectively connected to the standard volume chamber 1, and the vacuum flow guide orifice 2 is connected to the vacuum pump assembly 4. Figure 1As shown, gas source 5 is connected to standard volume chamber 1 via first vacuum valve 6 to provide the working gas for the flow meter. Vacuum pump assembly 4 is connected to standard volume chamber 1 via second vacuum valve 7 to extract gas from standard volume chamber 1. Vacuum flow guide orifice 2 is connected to standard volume chamber 1 via third vacuum valve 8 to extract a small gas flow rate. Vacuum flow guide orifice 2 and vacuum pump assembly 4 are connected via fourth vacuum valve 9. A vacuum detection element 3 is provided on standard volume chamber 1 to measure the pressure inside standard volume chamber 1. Vacuum detection element 3 is a vacuum gauge with the function of high-frequency timed transmission of pressure data. The flow meter also includes a gas flow outlet, which is located on the standard volume chamber 1. The gas flow rate supplied by the flow meter is controlled by the fifth vacuum valve 10. Under normal use, the fifth vacuum valve 10 is open, and the first vacuum valve 6, the second vacuum valve 7, the third vacuum valve 8, the fourth vacuum valve 9, the vacuum gauge, the vacuum flow guide orifice 2, the gas source 5, and the vacuum pump group 4 are all in a non-started state. During volume measurement, the fifth vacuum valve 10 is closed, and the first vacuum valve 6, the second vacuum valve 7, the third vacuum valve 8, the fourth vacuum valve 9, the vacuum gauge, the vacuum flow guide orifice 2, the gas source 5, and the vacuum pump group 4 are used for volume measurement.

[0025] This application couples the vacuum flow guide orifice 2, the gas source 5, and the vacuum pump assembly 4 to the standard volume chamber 1, eliminating the need to install, remove, and send the standard volume chamber 1 for testing. This allows for on-site measurement of the volume of a standard volume that is susceptible to external factors, improving the working quality of the flow meter equipment and maximizing its reliability and accuracy in field operation. This application can be used to measure the standard volume chamber 1 inside flow meter equipment that operates continuously for extended periods and cannot be shut down.

[0026] Specifically, the conductivity of vacuum flow guide orifice 2 is 10. -8 ~10 -9 Pa·m 3 / s.

[0027] Specifically, the time interval for recording the online pressure value of standard volume chamber 1. It is on the order of milliseconds.

[0028] Specifically, during calibration, the airflow inside standard volume chamber 1 should remain in a molecular flow state. The length of standard volume chamber 1 should not exceed 500 mm, and its maximum length should not exceed a preset volume, which is 20 L. The maximum vacuum level of standard volume chamber 1 must not exceed 10. -1 Pa.

[0029] Specifically, such as Figure 2 As shown, an online volume measurement method based on molecular conductivity includes: S1: Control vacuum pump group 4 to evacuate the standard volume chamber 1; S2: Control the gas source 5 to fill the standard volume chamber 1 with gas so that the pressure inside the standard volume chamber 1 is the first pressure; S3: Control the vacuum pump group 4 to evacuate the vacuum flow guide orifice 2; S4: Based on a preset time interval, air is drawn into the standard volume chamber 1 through the vacuum flow guide hole 2, and the pressure in the standard volume chamber 1 after each time interval is determined to be the intermediate pressure. S5: Determine the pressure inside the standard volume chamber 1 as the second pressure based on the preset duration; S6: Determine the volume of the standard volume chamber 1 based on the first pressure, the second pressure, the time interval, the intermediate pressure, and the conductance value of the vacuum flow guide orifice 2.

[0030] This application uses a gas source 5 to fill the standard volume chamber 1 with gas at a certain pressure. Then, a vacuum flow guide orifice 2 is used to guide the gas from the standard volume chamber 1 to another pressure. By integrating the outflowing gas flow rate and dividing by the pressure difference before and after the change in standard volume chamber 1, the volume of the standard volume chamber 1 after environmental influence is calculated. This application eliminates the need for loading, unloading, and testing of the standard volume; the volume of the standard volume, which is susceptible to external factors, can be obtained on-site, improving the working quality of the flow meter equipment and maximizing the reliability and accuracy of the flow meter equipment operating in the field.

[0031] Specifically, in step S6, the volume of the standard volume chamber 1 is determined based on the first pressure, the second pressure, the time interval, the intermediate pressure, and the conductivity value of the vacuum flow guide orifice 2. This includes: determining the total gas flow rate based on the time interval, the intermediate pressure, and the conductivity value of the vacuum flow guide orifice 2; determining the total pressure difference based on the first pressure and the second pressure; and determining the volume of the standard volume chamber 1 based on the ratio of the total gas flow rate to the total pressure difference. As shown in the following formula: Where P1 is the first pressure; P2 is the second pressure. denoted as time interval; P(n) is the intermediate pressure measured for the nth time; C is the conductivity value of the vacuum flow guide orifice 2.

[0032] Specifically, step S1 controls the vacuum pump assembly 4 to evacuate the standard volume chamber 1, including: connecting the standard volume chamber 1 and the vacuum pump assembly 4, disconnecting the standard volume chamber 1 from the gas source 5, disconnecting the standard volume chamber 1 from the vacuum flow guide orifice 2, and disconnecting the vacuum flow guide orifice 2 from the vacuum pump assembly 4; and starting the vacuum pump assembly 4 to evacuate the standard volume chamber 1. Further, the first vacuum valve 6, the fifth vacuum valve 10, the third vacuum valve 8, and the fourth vacuum valve 9 are closed, the second vacuum valve 7 is opened, and the vacuum pump assembly 4 is started to evacuate the standard volume chamber 1. Further, the pressure inside the standard volume chamber 1 is detected by the vacuum detection element 3; when the preset vacuum pressure is reached, the second vacuum valve 7 is closed.

[0033] Specifically, step S2 controls the gas source 5 to fill the standard volume chamber 1 with gas so that the pressure inside the standard volume chamber 1 is the first pressure. This includes: controlling the standard volume chamber 1 to disconnect from the vacuum pump group 4, connecting the standard volume chamber 1 to the gas source 5, disconnecting the standard volume chamber 1 from the vacuum flow guide orifice 2, and disconnecting the vacuum flow guide orifice 2 from the vacuum pump group 4; starting the gas source 5 to fill the standard volume chamber 1 with gas so that the pressure inside the standard volume chamber 1 is the first pressure. Further, based on step S1, the first vacuum valve 6 is controlled to open. At this time, the fifth vacuum valve 10, the third vacuum valve 8, the fourth vacuum valve 9, and the second vacuum valve 7 are in the closed state. The pressure inside the standard volume chamber 1 is detected by the vacuum detection element 3. When the first pressure P1 is reached, the first vacuum valve 6 and the gas source 5 are controlled to close.

[0034] Specifically, step S3 controls the vacuum pump group 4 to evacuate the vacuum flow guide orifice 2, including: disconnecting the standard volume chamber 1 from the vacuum pump group 4, disconnecting the standard volume chamber 1 from the gas source 5, disconnecting the standard volume chamber 1 from the vacuum flow guide orifice 2, and connecting the vacuum flow guide orifice 2 to the vacuum pump group 4; starting the vacuum pump group 4 to evacuate the vacuum flow guide orifice 2. Further, based on step S2, the fourth vacuum valve 9 is opened, at which time the fifth vacuum valve 10, the third vacuum valve 8, the first vacuum valve 6, and the second vacuum valve 7 are closed, and the vacuum pump group 4 is open, evacuating the vacuum flow guide orifice 2 and the pipeline between the vacuum flow guide orifice 2 and the vacuum pump group 4 to a high vacuum state. Figure 1 As shown, one end of the pipeline containing the fifth valve is connected to the standard volume chamber 1, and the other end is connected to the pipeline between the vacuum flow guide orifice 2 and the vacuum pump group 4. It can be understood that the pipeline between the vacuum flow guide orifice 2 and the vacuum pump group 4 is disconnected from the outside.

[0035] Specifically, step S4, based on a preset time interval, priming gas into the standard volume chamber 1 through the vacuum flow guide orifice 2, determines the pressure inside the standard volume chamber 1 after each time interval as the intermediate pressure. This includes: controlling the standard volume chamber 1 to disconnect from the vacuum pump group 4, the standard volume chamber 1 to disconnect from the gas source 5, connecting the standard volume chamber 1 to the vacuum flow guide orifice 2, and connecting the vacuum flow guide orifice 2 to the vacuum pump group 4; starting the vacuum pump group 4 to evacuate the standard volume chamber 1, and determining the pressure inside the standard volume chamber 1 after each time interval as the intermediate pressure based on the preset time interval. Further, based on step S3, controlling the third vacuum valve 8 to open, at which time the fifth vacuum valve 10, the first vacuum valve 6, and the second vacuum valve 7 are in the closed state, and the vacuum pump group 4 and the fourth vacuum valve 9 are in the open state, maintaining a high vacuum in the pipeline between the vacuum flow guide orifice 2 and the vacuum pump group 4 through the vacuum pump group 4. Further, within a preset priming time t, based on a preset time interval... The pressure inside the standard volume chamber 1 is measured multiple times using vacuum testing device 3, and an intermediate pressure P(n) is obtained for each measurement, where n is the nth measurement. Furthermore, the number of intermediate pressures is greater than a preset number of measurements, which is 3. For example, a total of 5 intermediate pressures of the standard volume chamber 1 are recorded, namely P(1), P(2), P(3), P(4), and P(5), with a recording interval of [missing information]. .

[0036] Specifically, step S5 determines the pressure inside the standard volume chamber 1 as the second pressure based on a preset time duration, including: disconnecting the standard volume chamber 1 from the vacuum pump group 4, disconnecting the standard volume chamber 1 from the gas source 5, disconnecting the standard volume chamber 1 from the vacuum flow guide orifice 2, and disconnecting the vacuum flow guide orifice 2 from the vacuum pump group 4; the pressure inside the standard volume chamber 1 is determined as the second pressure after the preset time duration. Further, the preset time duration is a preset priming time. Further, based on step S4, the third vacuum valve 8 is closed. At this time, the fifth vacuum valve 10, the first vacuum valve 6, and the second vacuum valve 7 are in the closed state, isolating the vacuum flow guide orifice 2 from the standard volume chamber 1. After the pressure stabilizes, the pressure measured by the vacuum detection element 3 at this moment is recorded as the second pressure P2.

[0037] Specifically, after calculating the volume of the labeled volume chamber according to step S6, the fourth vacuum valve 9 and the vacuum pump group 4 are closed. After calibration, the fifth vacuum valve 10 can be opened, and the flow meter device can be reused.

[0038] Specifically, the conductivity of vacuum flow guide orifice 2 is 10. -8 ~10 -9 Pa·m3 / s.

[0039] In one possible implementation, the sources of measurement uncertainty mainly include the vacuum gauge (0.4%), the vacuum flow guide orifice 2 (1%), and time (0.2%). Calculations show that the combined uncertainty of the flow meter device in this application can reach 1.1%.

[0040] This application uses a vacuum gauge to measure pressure values ​​P1, P2, and P(n). By integrating the amount of gas flowing out of the standard volume chamber 1 and dividing by the pressure difference, the volume of the standard volume chamber 1 after environmental changes is calculated. This application allows for on-site measurement of standard volumes susceptible to external factors, improving the working quality of flow meter equipment.

[0041] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "a plurality" refers to two or more unless otherwise expressly defined.

[0042] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An online volume measurement method based on molecular conductivity, characterized in that, This device is used for online volume measurement of the standard volume chamber of a flow meter. The flow meter includes a standard volume chamber, a vacuum flow guide orifice, a gas source, and a vacuum pump assembly. The vacuum flow guide orifice, the gas source, and the vacuum pump assembly are respectively connected to the standard volume chamber, and the vacuum flow guide orifice is connected to the vacuum pump assembly. The method includes: The vacuum pump unit is controlled to evacuate the standard volume chamber. The gas source is controlled to fill the standard volume chamber with gas, so that the pressure in the standard volume chamber is a first pressure; The vacuum pump unit is controlled to evacuate the vacuum flow guide orifice; Based on a preset time interval, air is drawn into the standard volume chamber through the vacuum flow guide orifice, and the pressure inside the standard volume chamber after each time interval is determined to be the intermediate pressure. The pressure inside the standard volume chamber is determined as the second pressure based on a preset duration. The volume of the standard volume chamber is determined based on the first pressure, the second pressure, the time interval, the intermediate pressure, and the conductivity value of the vacuum flow guide orifice.

2. The online volume measurement method based on molecular conductivity according to claim 1, characterized in that, The volume of the standard volume chamber is determined based on the first pressure, the second pressure, the time interval, the intermediate pressure, and the conductivity value of the vacuum flow guide orifice, including: The total gas flow rate is determined based on the time interval, the intermediate pressure, and the conductivity value of the vacuum flow guide orifice. Determine the total pressure difference based on the first pressure and the second pressure; The volume of the standard volume chamber is determined based on the ratio of the total gas flow rate to the total pressure difference.

3. The online volume measurement method based on molecular conductivity according to claim 1, characterized in that, Controlling the vacuum pump assembly to evacuate the standard volume chamber includes: The system controls the connection between the standard volume chamber and the vacuum pump group, the disconnection between the standard volume chamber and the gas source, the disconnection between the standard volume chamber and the vacuum flow guide orifice, and the disconnection between the vacuum flow guide orifice and the vacuum pump group. The vacuum pump unit is started to evacuate the standard volume chamber.

4. The online volume measurement method based on molecular conductivity according to claim 1, characterized in that, Controlling the gas source to fill the standard volume chamber with gas, so that the pressure in the standard volume chamber is a first pressure, includes: The control system disconnects the standard volume chamber from the vacuum pump assembly, connects the standard volume chamber to the gas source, disconnects the standard volume chamber from the vacuum flow guide orifice, and disconnects the vacuum flow guide orifice from the vacuum pump assembly. The gas source is activated to fill the standard volume chamber with gas, so that the pressure in the standard volume chamber is the first pressure.

5. The online volume measurement method based on molecular conductivity according to claim 1, characterized in that, Controlling the vacuum pump assembly to evacuate the vacuum flow guide orifice includes: The control system disconnects the standard volume chamber from the vacuum pump assembly, disconnects the standard volume chamber from the gas source, disconnects the standard volume chamber from the vacuum flow guide orifice, and connects the vacuum flow guide orifice to the vacuum pump assembly. The vacuum pump unit is started to evacuate the vacuum flow guide orifice.

6. The online volume measurement method based on molecular conductivity according to claim 1, characterized in that, Based on preset time intervals, air is drawn into the standard volume chamber through the vacuum flow guide orifice, and the pressure inside the standard volume chamber after each time interval is determined to be the intermediate pressure, including: The control system disconnects the standard volume chamber from the vacuum pump assembly, disconnects the standard volume chamber from the gas source, connects the standard volume chamber to the vacuum flow guide orifice, and connects the vacuum flow guide orifice to the vacuum pump assembly. The vacuum pump unit is started to evacuate the standard volume chamber. Based on a preset time interval, the pressure inside the standard volume chamber after each time interval is determined as the intermediate pressure.

7. The online volume measurement method based on molecular conductivity according to claim 1, characterized in that, Determining the pressure within the standard volume chamber as the second pressure based on a preset duration includes: The control system disconnects the standard volume chamber from the vacuum pump assembly, the standard volume chamber from the gas source, the standard volume chamber from the vacuum flow guide orifice, and the vacuum flow guide orifice from the vacuum pump assembly. The pressure inside the standard volume chamber is determined as the second pressure during the preset duration.

8. The online volume measurement method based on molecular conductivity according to claim 1, characterized in that, The number of intermediate pressures is greater than the preset number of times.

9. The online volume measurement method based on molecular conductivity according to claim 1, characterized in that, The conductivity of the vacuum flow-guiding orifice is 10. -8 ~10 -9 Pa·m 3 / s.

10. The online volume measurement method based on molecular conductivity according to claim 1, characterized in that, The volume of the standard volume chamber is smaller than the preset volume.

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