Vacuum pressure gas calibrating device and calibrating method

Abstract

The present application belongs to the technical field of measuring equipment, and discloses a vacuum pressure gas calibrating device and a calibrating method, which comprises a main partial pressure chamber, a plurality of auxiliary partial pressure chambers, a compressed air source, a molecular pump and a mechanical pump; a first standard pressure gauge, a pressure gauge to be tested interface, a fine tuning air release valve and a diaphragm vacuum gauge group are arranged on the main partial pressure chamber; the volumes of the plurality of auxiliary partial pressure chambers are different; a first standard pressure gauge stop valve is arranged between the first standard pressure gauge and the main partial pressure chamber, and a pressure gauge to be tested stop valve is arranged between the pressure gauge to be tested interface and the main partial pressure chamber. The readings of the standard pressure and the pressure gauge to be tested are compared after the auxiliary partial pressure chambers are divided and stabilized, so that the pressure calibration of the pressure gauge to be tested is realized. Compared with the conventional gas piston pressure method, the operation is simple, the absolute pressure or vacuum pressure transmitter and sensor can be accurately calibrated through partial pressure, the design of the fine tuning air release valve and the diaphragm vacuum gauge group can also meet the calibration of special pressure points, and the actual needs are fully met.

Description

Technical Field

[0001] This invention belongs to the field of measuring equipment technology and relates to a vacuum pressure gas calibration device and calibration method. Background Technology

[0002] Piston gauges are standard pressure measuring instruments with high accuracy, high repeatability, and high reliability, based on Pascal's law and the principle of fluid statics equilibrium. Existing piston gauges are further divided into gas piston gauges and liquid piston gauges according to the working medium. Gas piston gauges are required for the calibration of absolute pressure or vacuum pressure transmitters and sensors. Because the weights used with piston gauges are a fixed combination, absolute pressure or vacuum pressure transmitters and sensors can only be calibrated linearly and equally according to their range.

[0003] However, in practical applications, absolute pressure or vacuum pressure transmitters and sensors often require a measurement range of less than 5%. When using existing piston-type pressure gauges as standard calibrators according to the verification procedures, the weight of the piston-matched weights is fixed. For example, for -0.1 to 0 MPa, the matching weights are a combination of 5 kPa and 10 kPa. This means that when using gas pistons for calibration, only a minimum of 5% of the indicated value can be calibrated, which cannot meet the actual needs. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a vacuum pressure gas testing device and testing method.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a vacuum pressure gas testing device, comprising a main pressure chamber, several auxiliary pressure chambers, a compressed air source, a molecular pump, and a mechanical pump;

[0007] The main pressure chamber is equipped with a first standard pressure gauge, a pressure gauge under test interface, a fine-tuning vent valve, and a diaphragm vacuum gauge assembly; the several secondary pressure chambers have different volumes; a first standard pressure gauge shut-off valve is installed between the first standard pressure gauge and the main pressure chamber, and a pressure gauge under test shut-off valve is installed between the pressure gauge under test interface and the main pressure chamber.

[0008] A main outlet pipe is installed on the compressed air source. A first outlet pipe and a second outlet pipe are installed on the main outlet pipe. Several first outlet branch pipes and a second outlet branch pipe are installed on the first outlet pipe. The several first outlet branch pipes are connected to several secondary pressure chambers one by one. The second outlet pipe is connected to the main pressure chamber. A second standard pressure gauge is installed on the first outlet pipe. The second outlet branch pipe is connected to the main pressure chamber.

[0009] A molecular pump is equipped with a molecular pump suction pipe, which is further equipped with a first suction pipe and a second suction pipe. The first suction pipe is equipped with several first suction branches, which are connected to several secondary pressure chambers one by one. The second suction pipe is connected to the first exhaust pipe.

[0010] The mechanical pump is equipped with a mechanical pump suction pipe, and a third suction pipe and a fourth suction pipe are installed on the mechanical pump suction pipe. The third suction pipe is connected to the first suction pipe, and the fourth suction pipe is connected to the molecular pump.

[0011] A shut-off valve is installed on the main outlet pipe, the second outlet pipe, the first outlet branch pipe, the second outlet branch pipe, the molecular pump suction pipe, the first suction branch pipe, the third suction pipe, and the fourth suction pipe.

[0012] Optionally, the thin-film vacuum gauge group includes a first thin-film vacuum gauge, a second thin-film vacuum gauge, and a third thin-film vacuum gauge, which are connected in parallel and then connected to the main pressure chamber.

[0013] Optionally, the first thin-film vacuum gauge has a measurement range of 0–10 mbar and an accuracy class of 0.1%; the second thin-film vacuum gauge has a measurement range of 0–100 mbar and an accuracy class of 0.1%; and the third thin-film vacuum gauge has a measurement range of 0–1000 mbar and an accuracy class of 0.1%.

[0014] Optionally, the first standard pressure gauge has a measurement range of -0.1 to 0 MPa and an accuracy class of 0.05%; the second standard pressure gauge has a measurement range of -0.1 to 0.4 MPa and an accuracy class of 0.05%.

[0015] Optionally, among the plurality of secondary pressure chambers, one secondary pressure chamber has the same volume as the main pressure chamber, and the volumes of the remaining secondary pressure chambers are 1 / 12 to 1 / 2 times the volume of the main pressure chamber.

[0016] Optionally, seven secondary pressure chambers are provided, with the volumes of the seven secondary pressure chambers being 1 times, 1 / 2 times, 1 / 3 times, 1 / 4 times, 1 / 4 times, 1 / 6 times, and 1 / 12 times the volume of the main pressure chamber, respectively.

[0017] Optionally, the thin-film vacuum gauge assembly is connected to the flange of the main pressure chamber, the first standard pressure gauge is threadedly connected to the main pressure chamber, and the interface of the pressure gauge under test is a threaded interface.

[0018] Optionally, in use, the pressure gauge under test is connected to the pressure gauge under test interface, and the lower end interface of the pressure gauge under test and the lower end interface of the first standard pressure gauge are on the same horizontal plane.

[0019] In a second aspect, the present invention provides a vacuum pressure gas calibration method based on the above-described vacuum pressure gas calibration device, comprising:

[0020] Connect the pressure gauge under test to the main pressure chamber through the pressure gauge under test interface;

[0021] Pressure reduction process: The main pressure chamber and several secondary pressure chambers are evacuated by molecular pump and mechanical pump, and compressed air is injected into the main pressure chamber through compressed air source until the pressure in the main pressure chamber is the set pressure value. The pressure in the main pressure chamber is divided by several secondary pressure chambers. The readings of the standard pressure gauge and the pressure gauge under test are read and recorded at each calibration point.

[0022] Pressurization process: The main pressure chamber and several secondary pressure chambers are evacuated by molecular pumps and mechanical pumps. Then, compressed air is injected into the secondary pressure chambers through a compressed air source. The pressure in the secondary pressure chambers is divided by the main pressure chamber until the pressure in the main pressure chamber gradually increases to the set pressure value. The readings of the standard pressure gauge and the pressure gauge under test are read and recorded at each calibration point.

[0023] Preset pressure point calibration process: The main pressure chamber and several auxiliary pressure chambers are evacuated by molecular pump and mechanical pump, and compressed air with a preset pressure value is injected into the main pressure chamber by fine-tuning the vent valve and the diaphragm vacuum gauge group. The readings of the standard pressure gauge and the pressure gauge under test are read and recorded respectively.

[0024] Determine whether the pressure gauge under test is qualified based on the readings of the standard pressure gauge and the pressure gauge under test.

[0025] Optionally, determining whether the pressure gauge under test is qualified based on the readings of the standard pressure gauge and the pressure gauge under test includes:

[0026] If the error = PG2 - PG1 ≤ PG2 × accuracy class × 100%, and the absolute value of the difference between the values ​​of the pressure gauge under test during the pressure reduction and pressure increase processes ≤ PG2 × class × 100%, then the pressure gauge under test is qualified; otherwise, the pressure gauge under test is unqualified. Wherein, PG2 is the reading of the pressure gauge under test, and PG1 is the reading of the first standard pressure gauge.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention relates to a vacuum pressure gas calibration device. By setting up several secondary pressure chambers to divide the pressure of a main pressure chamber, it can achieve pressure increase and decrease in the main pressure chamber. Furthermore, the different volumes of the secondary pressure chambers allow for different pressure division ratios. When gas of known pressure enters the main pressure chamber, over a period of time, a standard gas pressure is generated within the main pressure chamber. After pressure division and stabilization by the secondary pressure chambers, the standard pressure is compared with the reading of the pressure gauge under test to calibrate the pressure gauge. Compared to conventional gas piston pressure methods, this device is simpler to operate. Accurate calibration of absolute pressure or vacuum pressure transmitters and sensors can be achieved through pressure division. Additionally, by adding interfaces for the pressure gauges under test, multiple absolute pressure or vacuum pressure transmitters and sensors can be calibrated simultaneously, improving efficiency. Moreover, based on the design of the fine-tuning vent valve and the thin-film vacuum gauge assembly, it can also meet the calibration requirements at special pressure points, enabling calibration of arbitrary values ​​and fully satisfying practical needs. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the vacuum pressure gas calibration device according to an embodiment of the present invention.

[0030] Wherein: 1-Compressed air source; 2-Molecular pump; 3-Mechanical pump; 4-Main outlet pipe shut-off valve; 5-First standard pressure gauge shut-off valve; 6-Test pressure gauge shut-off valve; 7-Second outlet branch pipe shut-off valve; 8-Third intake pipe shut-off valve; 9-Molecular pump intake pipe shut-off valve; 10-Second outlet pipe shut-off valve; 11-Main partial pressure chamber; 12-First secondary partial pressure chamber; 13-Second secondary partial pressure chamber; 14-Third secondary partial pressure chamber; 15-Fourth secondary partial pressure chamber; 16-Fifth secondary partial pressure chamber; 17-Sixth secondary partial pressure chamber; 18-Seventh secondary partial pressure chamber; 19-Fine-tuning vent valve; 21-First standard pressure gauge; 22-Test pressure gauge; 23-First thin-film vacuum gauge; 24-Second thin-film vacuum gauge; 25-Third thin-film vacuum gauge; 26 - Second standard pressure gauge; 31 - First shut-off valve of the first outlet branch pipe; 32 - Second shut-off valve of the first outlet branch pipe; 33 - Third shut-off valve of the first outlet branch pipe; 34 - Fourth shut-off valve of the first outlet branch pipe; 35 - Fifth shut-off valve of the first outlet branch pipe; 36 - Sixth shut-off valve of the first outlet branch pipe; 37 - Seventh shut-off valve of the first outlet branch pipe; 41 - First shut-off valve of the first intake branch pipe; 42 - Second shut-off valve of the first intake branch pipe; 43 - Third shut-off valve of the first intake branch pipe; 44 - Fourth shut-off valve of the first intake branch pipe; 45 - Fifth shut-off valve of the first intake branch pipe; 46 - Sixth shut-off valve of the first intake branch pipe; 47 - Seventh shut-off valve of the first intake branch pipe; 48 - Fourth intake pipe shut-off valve. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0033] The present invention will now be described in further detail with reference to the accompanying drawings:

[0034] See Figure 1In one embodiment of the present invention, a vacuum pressure gas calibration device is provided, comprising a main pressure chamber 11, several secondary pressure chambers, a compressed air source 1, a molecular pump 2, and a mechanical pump 3; a first standard pressure gauge 21, a pressure gauge under test interface, a fine-tuning vent valve 19, and a thin-film vacuum gauge assembly are provided on the main pressure chamber 11; the several secondary pressure chambers have different volumes; a first standard pressure gauge shut-off valve 5 is provided between the first standard pressure gauge 21 and the main pressure chamber 11, and a pressure gauge under test shut-off valve 6 is provided between the pressure gauge under test interface and the main pressure chamber 11; a main exhaust pipe is provided on the compressed air source 1, and a first exhaust pipe and a second exhaust pipe are provided on the main exhaust pipe, and several first exhaust branches and a second exhaust branch are provided on the first exhaust pipe, with the several first exhaust branches respectively connected to several secondary pressure chambers one by one; the second exhaust pipe is connected to the main pressure chamber 1. The pressure chamber 11 is connected; a second standard pressure gauge 26 is installed on the first outlet pipe; the second outlet branch pipe is connected to the main pressure chamber 11; the molecular pump 2 is equipped with a molecular pump suction pipe, on which a first and second suction pipe are installed, and on the first suction pipe are several first suction branches, which are respectively connected to several secondary pressure chambers; the second suction pipe is connected to the first outlet pipe; the mechanical pump 3 is equipped with a mechanical pump suction pipe, on which a third and fourth suction pipe are installed, the third suction pipe is connected to the first suction pipe, and the fourth suction pipe is connected to the molecular pump 2; a shut-off valve is installed on the main outlet pipe, the second outlet pipe, the first outlet branch pipe, the second outlet branch pipe, the molecular pump suction pipe, the first suction branch pipe, the third suction pipe, and the fourth suction pipe.

[0035] This invention relates to a vacuum pressure gas calibration device, comprising a shut-off valve, a standard pressure gauge 21, a pressure gauge under test 22, a thin-film vacuum gauge assembly, a pumping system, a main pressure chamber 11, several auxiliary pressure chambers, and a gas supply system. When gas of known pressure enters the pressure stabilizing chamber, after a period of accumulation, a standard gas pressure is generated in the main pressure chamber 11. After pressure stabilization, the readings of the standard pressure 21 and the pressure gauge under test 22 are compared to calibrate the pressure of the pressure gauge 22. Compared with conventional gas piston pressure methods, this device and method are simple to operate. Accurate calibration of absolute pressure or vacuum pressure transmitters and sensors can be achieved through pressure division. Furthermore, by fine-tuning the vent valve 19 and the thin-film vacuum gauge assembly, calibration at specific pressure points can also be performed.

[0036] In one possible implementation, the thin-film vacuum gauge group includes a first thin-film vacuum gauge 23, a second thin-film vacuum gauge 24, and a third thin-film vacuum gauge 25, which are connected in parallel to the main pressure chamber 11.

[0037] The thin-film vacuum gauge assembly has a range of 0 to 1000 mbar, covering a vacuum pressure range of -0.1 to 0 MPa.

[0038] In one possible implementation, the first thin-film vacuum gauge 23 has a measurement range of 0–10 mbar and an accuracy class of 0.1%; the second thin-film vacuum gauge 24 has a measurement range of 0–100 mbar and an accuracy class of 0.1%; and the third thin-film vacuum gauge 25 has a measurement range of 0–1000 mbar and an accuracy class of 0.1%. Optionally, the first standard pressure gauge 21 has a measurement range of -0.1–0 MPa and an accuracy class of 0.05%; and the second standard pressure gauge 26 has a measurement range of -0.1–0.4 MPa and an accuracy class of 0.05%.

[0039] In one possible implementation, the thin-film vacuum gauge assembly is flange-connected to the main pressure chamber 11, the first standard pressure gauge 21 is threadedly connected to the main pressure chamber 11, and the interface of the pressure gauge under test is a threaded interface.

[0040] In one possible implementation, when in use, the pressure gauge 22 under test is connected to the pressure gauge interface under test, and the lower end interface of the pressure gauge 22 under test is at the same horizontal plane as the lower end interface of the first standard pressure gauge 21.

[0041] In one possible implementation, the volume of one of the plurality of secondary pressure chambers is the same as the volume of the main pressure chamber 11, and the volumes of the remaining secondary pressure chambers are 1 / 12 to 1 / 2 times the volume of the main pressure chamber 11.

[0042] In this embodiment, seven secondary pressure chambers are provided, and the volumes of the seven secondary pressure chambers are respectively 1 times the volume of the main pressure chamber 11, 1 / 2 times the volume of the main pressure chamber 11, 1 / 3 times the volume of the main pressure chamber 11, 1 / 4 times the volume of the main pressure chamber 11, 1 / 4 times the volume of the main pressure chamber 11, 1 / 6 times the volume of the main pressure chamber 11, and 1 / 12 times the volume of the main pressure chamber 11.

[0043] The system includes a first secondary pressure chamber 12, a second secondary pressure chamber 13, a third secondary pressure chamber 14, a fourth secondary pressure chamber 15, a fifth secondary pressure chamber 16, a sixth secondary pressure chamber 17, and a seventh secondary pressure chamber 18.

[0044] A main outlet pipe shut-off valve 4 is installed on the main outlet pipe, a second outlet pipe shut-off valve 10 is installed on the second outlet pipe, and a first outlet pipe shut-off valve 31, a second outlet pipe shut-off valve 32, a third outlet pipe shut-off valve 33, a fourth outlet pipe shut-off valve 34, a fifth outlet pipe shut-off valve 35, a sixth outlet pipe shut-off valve 36, and a seventh outlet pipe shut-off valve 37 are respectively installed on the seven first outlet pipes. A second outlet pipe shut-off valve 7 is installed on the second outlet pipe, a molecular pump suction pipe shut-off valve 9 is installed on the molecular pump suction pipe, and a first suction pipe shut-off valve 41, a second suction pipe shut-off valve 42, a third suction pipe shut-off valve 44, a fourth suction pipe shut-off valve 44, a fifth suction pipe shut-off valve 45, a sixth suction pipe shut-off valve 46, and a seventh suction pipe shut-off valve 47 are installed on the first suction pipe. A third suction pipe stop valve 8 is installed on the third suction pipe, and a fourth suction pipe stop valve 48 is installed on the fourth suction pipe.

[0045] Furthermore, when the pipeline is short enough and the orifice is small enough, the volume of the pipeline valves can be ignored for the entire system.

[0046] In another embodiment of the present invention, a vacuum pressure gas testing method is provided, based on the above-described vacuum pressure gas testing device, comprising the following steps:

[0047] The pressure gauge under test 22 is connected to the main pressure chamber 11 through the pressure gauge under test interface; Depressurization process: The main pressure chamber 11 and several secondary pressure chambers are evacuated by the molecular pump 2 and the mechanical pump 3, and compressed air is injected into the main pressure chamber 11 through the compressed air source 1 until the pressure of the main pressure chamber 11 reaches the set pressure value. The pressure is divided in the main pressure chamber 11 by several secondary pressure chambers. The readings of the standard pressure gauge 21 and the pressure gauge under test 22 are read and recorded at each calibration point; Pressure increase process: The main pressure chamber 11 and several secondary pressure chambers are evacuated by the molecular pump 2 and the mechanical pump 3, and then compressed air is injected into the secondary pressure chambers through the compressed air source 1. The pressure is gradually increased to the set pressure value in the main pressure chamber 11 by dividing the pressure in the secondary pressure chambers through the main pressure chamber 11. The readings of the standard pressure gauge 21 and the pressure gauge under test 22 are read and recorded at each calibration point. The preset pressure point calibration process is as follows: the main pressure chamber 11 and several secondary pressure chambers are evacuated by the molecular pump 2 and the mechanical pump 3, and compressed air at the preset pressure value is injected into the main pressure chamber 11 through the fine-tuning vent valve 19 and the diaphragm vacuum gauge group. The readings of the standard pressure gauge 21 and the pressure gauge under test 22 are read and recorded. The pressure gauge under test 22 is judged to be qualified based on the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0048] Optionally, the step of determining whether the pressure gauge 22 under test is qualified based on the readings of the standard pressure gauge 21 and the pressure gauge 22 under test includes: when the error = PG2 - PG1 ≤ PG2 × accuracy class × 100%, and the absolute value of the difference between the values ​​of the pressure gauge 22 under test during the depressurization and pressurization processes ≤ PG2 × class × 100%, then the pressure gauge 22 under test is qualified; otherwise, the pressure gauge 22 under test is unqualified; wherein, PG2 is the reading of the pressure gauge 22 under test, and PG1 is the reading of the first standard pressure gauge 21.

[0049] Specifically, the vacuum pressure gas verification method includes the following detailed steps:

[0050] The process of reducing blood pressure:

[0051] 1. Power on and preheat the standard pressure gauge 21; after the pressure gauge under test 22, close the main outlet pipe shut-off valve 4, open all other shut-off valves, and use a combination of molecular pump 2 and mechanical pump 3 to evacuate the main pressure chamber 11, the first auxiliary pressure chamber 12, the second auxiliary pressure chamber 13, the third auxiliary pressure chamber 14, the fourth auxiliary pressure chamber 15, the fifth auxiliary pressure chamber 16, the sixth auxiliary pressure chamber 17, and the seventh auxiliary pressure chamber 18, as well as all pipelines. Then close all valves and open the main outlet pipe shut-off valve 4, the first standard pressure gauge shut-off valve 5, the pressure gauge under test shut-off valve 6, and the second outlet pipe shut-off valve 10. With the help of the standard pressure gauge 26, introduce dry air from the compressed air source 1 into the main pressure chamber 11 and charge it to one standard atmosphere. At this time, the pressure value of the main pressure chamber 11 and the upper pipeline is one standard atmosphere, 0.1 MPa. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0052] 2. After closing the main outlet valve 4 and the second outlet valve 10, and opening the fourth outlet valve 34 of the first outlet branch pipe, the pressure in the main pressure chamber 11 and the fourth auxiliary pressure chamber 15 will be balanced. According to the ideal gas equation of state: p1V1 / T1=p2V2 / T2 (at the same temperature, T1=T2), the pressure after balance is calculated to be 60×0.1=(60+15)×0.08. At this time, the pressure in the main pressure chamber 11 is 0.08MP. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0053] 3. After closing the fourth shut-off valve 34 of the first outlet branch pipe and opening the fifth shut-off valve 35 and the seventh shut-off valve 37 of the first outlet branch pipe, the pressures of the main pressure chamber 11, the fifth auxiliary pressure chamber 16, and the seventh auxiliary pressure chamber 18 are balanced. According to the ideal gas equation of state: p1V1 / T1=p2V2 / T2 (at the same temperature, T1=T2), the pressure after balance is calculated to be 60×0.08=(60+15+5)×0.06. At this time, the pressure of the main pressure chamber 11 is 0.06MP. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0054] 4. After closing the fifth shut-off valve 35 and the seventh shut-off valve 37 of the first outlet gas branch pipe, open the second shut-off valve 32 of the first outlet gas branch pipe. The pressure in the main pressure chamber 11 and the second auxiliary pressure chamber 13 will be balanced. According to the ideal gas equation of state: p1V1 / T1=p2V2 / T2 (T1=T2 at the same temperature), the pressure after balance is calculated to be 60×0.06=(60+30)×0.04. At this time, the pressure in the main pressure chamber 11 is 0.04MP. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0055] 5. After closing the second shut-off valve 32 of the first outflow branch pipe, open the second shut-off valve 42 of the first intake branch pipe, the fourth shut-off valve 44 of the first intake branch pipe, and the fifth shut-off valve 45 of the first intake branch pipe. Use the combination of molecular pump 2 and mechanical pump 3 to evacuate the second secondary pressure chamber 13, the fourth secondary pressure chamber 15, and the fifth secondary pressure chamber 16 of the pressure stabilizing chamber. Then open the second shut-off valve 32 of the first outflow branch pipe, the fourth shut-off valve 34 of the first outflow branch pipe, and the first outflow branch pipe... The pressures of the fifth shut-off valve 35, main pressure chamber 11, second auxiliary pressure chamber 13, fourth auxiliary pressure chamber 15, and fifth auxiliary pressure chamber 16 are balanced. According to the ideal gas law: p1V1 / T1=p2V2 / T2 (at the same temperature, T1=T2), the pressure after balance is calculated to be 60×0.04=(60+30+15+15)×0.02. At this time, the pressure of the main pressure chamber 11 is 0.02MP. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0056] 6. Repeat step 5 and calculate the equilibrium pressure according to the ideal gas equation of state: p1V1 / T1=p2V2 / T2 (at the same temperature, T1=T2). The pressure is 60×0.02=(60+30+15+15)×0.01. At this time, the pressure in the main pressure chamber 11 is 0.01MP. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0057] 7. Repeat step 6 and calculate the equilibrium pressure using the ideal gas equation of state: p1V1 / T1=p2V2 / T2 (at the same temperature, T1=T2). The pressure is 60×0.01=(60+30+15+15)×0.005. At this time, the pressure in the main pressure chamber 11 is 0.005MPa. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0058] 8. Repeat step 7 and calculate the equilibrium pressure using the ideal gas equation of state: p1V1 / T1=p2V2 / T2 (at the same temperature, T1=T2). The pressure is 60×0.005=(60+30+15+15)×0.0025. At this time, the pressure in the main pressure chamber 11 is 0.0025MPa. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0059] The boost process:

[0060] 9. After evacuating all pipeline pressure stabilizing chambers and pressure dividing chambers, close all shut-off valves. Then open the main outlet shut-off valve 4, the second outlet shut-off valve 10, and the first outlet branch shut-off valve 34. Fill the fourth auxiliary pressure dividing chamber 15 with dry compressed air from the dry compressed air source 1 to a standard atmosphere. Then close the main outlet shut-off valve 4 and the second outlet shut-off valve 10. Then open the second outlet branch shut-off valve 7 to balance the pressure in the main pressure dividing chamber 11 and the fourth auxiliary pressure dividing chamber 15. According to the ideal gas equation of state: p1V1 / T1=p2V2 / T2 (at the same temperature, T1=T2), the pressure after balance is calculated to be 15×0.1=(60+15)×0.02. At this time, the pressure in the main pressure dividing chamber 11 is 0.02MPa. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0061] 10. Open the main outlet pipe shut-off valve 4 and the first outlet branch pipe shut-off valve 31 to fill the first secondary pressure chamber 12 with dry air from the compressed air source 1 to a standard atmosphere. Then close the main outlet pipe shut-off valve 4 and open the second outlet branch pipe shut-off valve 7 to balance the pressure in the main pressure chamber 11 and the first secondary pressure chamber 12. According to the ideal gas equation of state: p1V1 / T1=p2V2 / T2 (at the same temperature, T1=T2), the pressure after balance is calculated to be 60×0.1=60×0.02+(60+60)×0.04. At this time, the pressure in the main pressure chamber 11 is 0.04MP. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0062] 11. Open the first shut-off valve 31 of the first outlet branch pipe and the second shut-off valve 32 of the first outlet branch pipe to fill the first auxiliary pressure chamber 12 and the second auxiliary pressure chamber 13 with dry air from the compressed air source 1 to a standard atmosphere. Then close the main outlet pipe shut-off valve 4 and open the second outlet branch pipe shut-off valve 7 to balance the pressure in the main pressure chamber 11, the first auxiliary pressure chamber 12 and the second auxiliary pressure chamber 13. According to the ideal gas equation of state: p1V1 / T1=p2V2 / T2 (at the same temperature T1=T2), the pressure after balance is calculated to be (60+30)×0.1=60×0.04+(60+60+30)×0.06. At this time, the pressure in the main pressure chamber 11 is 0.06MPa. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0063] 12. Open the main outlet pipe shut-off valve 4, the first outlet branch pipe first shut-off valve 31, and the first outlet branch pipe sixth shut-off valve 36. Fill the first auxiliary pressure chamber 12 and the sixth auxiliary pressure chamber 17 with dry air from the compressed air source 1 to two standard atmospheres. Then close the main outlet pipe shut-off valve 4 and open the second outlet branch pipe shut-off valve 7 to balance. Calculate the pressure in the main pressure chamber 11, the first auxiliary pressure chamber 12, and the sixth auxiliary pressure chamber 17 according to the ideal gas equation of state: p1V1 / T1=p2V2 / T2 (at the same temperature, T1=T2). The balanced pressure is (60+10)×0.2=60×0.06+(60+60+10)×0.08. At this time, the pressure in the main pressure chamber 11 is 0.08MP. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0064] 13. Open the main outlet valve 4 and the second outlet valve 10, fill the main pressure chamber 11 with dry air from the compressed air source 1 to a standard atmosphere, and then close the main outlet valve 4 and the second outlet valve 10. At this time, the main pressure chamber 11 is 0.1 MPa. Read and record the readings of the standard pressure gauge 21 and the pressure gauge under test 22.

[0065] For special cases, such as when the vacuum pressure is 150Pa, open the second outlet branch valve 7, the molecular pump suction pipe valve 9, and the fourth suction pipe valve 48, and close all other outlet valves. Then, the mechanical pump 3, in conjunction with the molecular pump 2, directly pumps the main pressure chamber 11 to the vacuum floor. After that, use the fine-tuning venting valve 19 in conjunction with the thin-film vacuum gauge 23 to vent the main pressure chamber 11 to a vacuum pressure of 150Pa. Then, read and record the readings of the thin-film vacuum gauge 23 and the pressure gauge under test 22.

[0066] For special cases, such as when the vacuum pressure is 2450Pa, open the second branch gas outlet shut-off valve 7, the molecular pump suction pipe shut-off valve 9, and the fourth branch suction pipe shut-off valve 48. After closing all other shut-off valves, the mechanical pump 3, in conjunction with the molecular pump 2, directly pumps the main pressure chamber 11 to the vacuum floor. Then, use the fine-tuning venting valve 19 in conjunction with the thin-film vacuum gauge 24 to vent the gas to the main pressure chamber 11. When the vacuum pressure reaches 2450Pa, read and record the readings of the thin-film vacuum gauge 24 and the pressure gauge under test 22.

[0067] For special cases, such as when the vacuum pressure is 35700Pa, open the second branch gas outlet shut-off valve 7, the molecular pump suction pipe shut-off valve 9, and the fourth branch suction pipe shut-off valve 48. After closing all other shut-off valves, the mechanical pump 3, in conjunction with the molecular pump 2, directly pumps the main pressure chamber 11 to the vacuum floor. Then, use the fine-tuning venting valve 19 in conjunction with the thin-film vacuum gauge 25 to vent the gas to the main pressure chamber 11. When the vacuum pressure reaches 35700Pa, read and record the readings of the thin-film vacuum gauge 25 and the pressure gauge under test 22.

[0068] After the calibration is completed, close the main outlet valve 4, the first standard pressure gauge valve 5, and the pressure gauge under test valve 6. Remove the pressure gauge under test 22 and let the mechanical pump 3 work with the molecular pump 2 to continue evacuating the vacuum. After all components of the entire device except the upper part of the main outlet valve 4 are in a vacuum state, close all valves to stop the molecular pump 2 and the mechanical pump 3. The system can then perform the next measurement.

[0069] Vacuum pressure calculation error method: Standard pressure gauge 21 reads and records the standard value PG1 and the pressure gauge under test 22 reads and records the calibration value PG2. Then, according to the error = PG2 - PG1 ≤ PG2 × grade × 100%, and the absolute value of the pressure drop and pressure rise difference of the pressure gauge under test 22 ≤ PG2 × grade × 100%, it is judged as qualified. The reading PG2 of the pressure gauge under test 22 may be a specific digital reading or voltage value (such as 0-10V or 0-5V) or current value (such as 4-20mA). When it is a current or voltage value, the standard value is replaced with the corresponding standard current or voltage value.

[0070] In summary, the vacuum pressure gas calibration device of the present invention, by setting up several secondary pressure chambers to divide the pressure of the main pressure chamber 11, can realize the pressure increase and decrease of the main pressure chamber 11. Furthermore, the different volumes of the secondary pressure chambers allow for different pressure division ratios. When gas of known pressure enters the main pressure chamber, after a period of accumulation, a standard gas pressure is generated within the main pressure chamber 11. After pressure division and stabilization by the secondary pressure chambers, the reading of the standard pressure 21 is compared with that of the pressure gauge 22 under test, thus achieving pressure calibration of the pressure gauge 22. Compared with the conventional gas piston pressure method, the operation is simpler, and the pressure division can achieve accurate calibration of absolute pressure or vacuum pressure transmitters and sensors. Moreover, based on the design of the fine-tuning vent valve 19 and the thin-film vacuum gauge assembly, it can also meet the calibration requirements of special pressure points, enabling calibration of any value and fully satisfying practical needs.

[0071] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A vacuum pressure gas testing device, characterized in that, It includes a main pressure chamber (11), several secondary pressure chambers, a compressed air source (1), a molecular pump (2), and a mechanical pump (3); The main pressure chamber (11) is equipped with a first standard pressure gauge (21), a pressure gauge under test interface, a fine-tuning vent valve (19), and a thin-film vacuum gauge assembly; the volumes of the several secondary pressure chambers are different; a first standard pressure gauge shut-off valve (5) is set between the first standard pressure gauge (21) and the main pressure chamber (11), and a pressure gauge under test shut-off valve (6) is set between the pressure gauge under test interface and the main pressure chamber (11); A main outlet pipe is provided on the compressed air source (1). A first outlet pipe and a second outlet pipe are provided on the main outlet pipe. Several first outlet branches and a second outlet branch are provided on the first outlet pipe. Several first outlet branches are connected to several secondary pressure chambers one by one. The second outlet pipe is connected to the main pressure chamber (11). A second standard pressure gauge (26) is provided on the first outlet pipe. The second outlet branch is connected to the main pressure chamber (11). A molecular pump suction pipe is provided on the molecular pump (2). A first suction pipe and a second suction pipe are provided on the molecular pump suction pipe. Several first suction branches are provided on the first suction pipe. Several first suction branches are respectively connected to several secondary pressure chambers one by one. The second suction pipe is connected to the first exhaust pipe. The mechanical pump (3) is equipped with a mechanical pump suction pipe. The mechanical pump suction pipe is equipped with a third suction pipe and a fourth suction pipe. The third suction pipe is connected to the first suction pipe, and the fourth suction pipe is connected to the molecular pump (2). A shut-off valve is installed on the main outlet pipe, the second outlet pipe, the first outlet branch pipe, the second outlet branch pipe, the molecular pump suction pipe, the first suction branch pipe, the third suction pipe, and the fourth suction pipe. The thin-film vacuum gauge group includes a first thin-film vacuum gauge (23), a second thin-film vacuum gauge (24) and a third thin-film vacuum gauge (25). The first thin-film vacuum gauge (23), the second thin-film vacuum gauge (24) and the third thin-film vacuum gauge (25) are connected in parallel and then connected to the main pressure chamber (11). The first thin-film vacuum gauge (23) has a measurement range of 0~10 mbar and an accuracy class of 0.1%; the second thin-film vacuum gauge (24) has a measurement range of 0~100 mbar and an accuracy class of 0.1%; the third thin-film vacuum gauge (25) has a measurement range of 0~1000 mbar and an accuracy class of 0.1%. The first standard pressure gauge (21) has a measurement range of -0.1 to 0 MPa and an accuracy class of 0.05%; the second standard pressure gauge (26) has a measurement range of -0.1 to 0.4 MPa and an accuracy class of 0.05%. Among the several secondary pressure chambers, the volume of one secondary pressure chamber is the same as the volume of the main pressure chamber (11), and the volumes of the remaining secondary pressure chambers are 1 / 12 to 1 / 2 times the volume of the main pressure chamber (11).

2. The vacuum pressure gas calibration device according to claim 1, characterized in that, The system comprises seven secondary pressure chambers, each with a volume equal to that of the main pressure chamber (11), 1 / 2 the volume of the main pressure chamber (11), 1 / 3 the volume of the main pressure chamber (11), 1 / 4 the volume of the main pressure chamber (11), 1 / 4 the volume of the main pressure chamber (11), 1 / 6 the volume of the main pressure chamber (11), and 1 / 12 the volume of the main pressure chamber (11).

3. The vacuum pressure gas calibration device according to claim 1, characterized in that, The thin-film vacuum gauge assembly is connected to the flange of the main pressure chamber (11), the first standard pressure gauge (21) is threadedly connected to the main pressure chamber (11), and the pressure gauge under test has a threaded interface.

4. The vacuum pressure gas testing device according to claim 1, characterized in that, When in use, the pressure gauge under test (22) is connected to the pressure gauge under test interface, and the lower end interface of the pressure gauge under test (22) is at the same level as the lower end interface of the first standard pressure gauge (21).

5. A method for vacuum pressure gas calibration based on the vacuum pressure gas calibration device according to any one of claims 1 to 4, characterized in that, include: The pressure gauge under test (22) is connected to the main pressure chamber (11) through the pressure gauge under test interface; Pressure reduction process: The main pressure chamber (11) and several secondary pressure chambers are evacuated by a molecular pump (2) and a mechanical pump (3), and compressed air is injected into the main pressure chamber (11) through a compressed air source (1) to the pressure value of the main pressure chamber (11) to the set air pressure value. The main pressure chamber (11) is divided by several secondary pressure chambers. The readings of the first standard pressure gauge (21) and the pressure gauge under test (22) are read and recorded at each calibration point. Pressure boosting process: The main pressure chamber (11) and several secondary pressure chambers are evacuated by a molecular pump (2) and a mechanical pump (3). Then, compressed air is injected into the secondary pressure chambers through a compressed air source (1), and the pressure in the secondary pressure chambers is gradually increased to the set pressure value through the main pressure chamber (11). The readings of the first standard pressure gauge (21) and the pressure gauge under test (22) are read and recorded at each calibration point. Preset pressure point verification process: The main pressure chamber (11) and several auxiliary pressure chambers are evacuated by a molecular pump (2) and a mechanical pump (3), and compressed air with a preset pressure value is injected into the main pressure chamber (11) through a fine-tuning vent valve (19) and a thin-film vacuum gauge group. The readings of the first standard pressure gauge (21) and the pressure gauge under test (22) are read and recorded respectively. The test pressure gauge (22) is judged to be qualified based on the readings of the first standard pressure gauge (21) and the pressure gauge under test (22).

6. The vacuum pressure gas verification method according to claim 5, characterized in that, The process of determining whether the pressure gauge (22) under test is qualified based on the readings of the first standard pressure gauge (21) and the pressure gauge under test (22) includes: When the error = PG2 - PG1 ≤ PG2 × accuracy class × 100%, and the absolute value of the difference between the values ​​of the pressure gauge (22) under test during the pressure reduction and pressure increase processes ≤ PG2 × class × 100%, then the pressure gauge (22) under test is qualified; otherwise, the pressure gauge (22) under test is unqualified; where PG2 is the reading of the pressure gauge (22) under test, and PG1 is the reading of the first standard pressure gauge (21).

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