Pressure instrument calibration equipment

Abstract

The utility model belongs to the technical field of pressure instrument calibration, and discloses a pressure instrument calibration device, in the pressure instrument calibration device, a sealing cavity capable of forming a seal is formed in a pressure-proof box, and the sealing cavity is used for placing a pressure instrument; the pressure-proof box is also provided with a light-transmitting hole communicated with the sealing cavity, and the light-transmitting hole is provided with a window made of a light-transmitting material; the pressure pump is used for blowing gas into the sealing cavity; the vacuum pump is used for pumping gas in the sealing cavity; the standard pressure gauge is used for obtaining the gas pressure in the sealing cavity, the pressure gauge can be placed in the sealing cavity to form sealing, gas is blown into the sealing cavity through the pressure pump, and the gas in the sealing cavity is pumped out through the vacuum pump, so that the gas pressure in the sealing cavity is adjusted, and high-altitude environments at different heights are simulated. The reading of the pressure instrument is observed through the window, and the reading is compared with the gas pressure obtained by the standard pressure gauge, so that the pressure instrument can be calibrated.

Description

Technical Field

[0001] This utility model relates to the field of pressure instrument calibration technology, and in particular to pressure instrument calibration equipment. Background Technology

[0002] Aircraft absolute pressure gauges and aircraft atmospheric pressure sensors need to be calibrated regularly.

[0003] The calibration structure of existing aviation absolute pressure gauges is as follows: Figure 1 As shown, the pressure generator 1200 is connected to both the aviation absolute pressure gauge 1000 to be calibrated and the atmospheric data tester 1100 as a standard instrument. The pressure generator 1200 serves as the pressure source, and the aviation absolute pressure gauge 1000 and the atmospheric data tester 1100 simultaneously detect the pressure they receive. The detected values ​​of the two instruments are compared and then calibrated.

[0004] The calibration structure of pressure sensors in the prior art is as follows: Figure 2 As shown, the piston pressure gauge 2100 can be a gas piston pressure gauge or a liquid piston pressure gauge, which serves as a pressure source. The measuring end of the atmospheric pressure sensor 2000 is connected to the test port of the piston pressure gauge 2100. The secondary instrument 2200 is connected to the atmospheric pressure sensor 2000 via a wire and is used to display the measurement data of the atmospheric pressure sensor 2000. The above measurement data can be compared with the output pressure of the piston pressure gauge 2100 and calibrated.

[0005] However, all of the above calibration structures have a problem: the calibration process is completed on the ground, not in a real high-altitude environment. Therefore, the calibrated airborne absolute pressure gauge and airborne atmospheric pressure sensor may still have errors in a high-altitude environment. Utility Model Content

[0006] According to one aspect of the present invention, the present invention provides a pressure gauge calibration device to solve the problem that calibrated aviation absolute pressure gauges and aviation atmospheric pressure sensors may still have errors in high-altitude environments in the prior art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] Pressure gauge calibration equipment includes:

[0009] The pressure chamber has a sealed cavity capable of forming a seal for housing pressure gauges; the pressure chamber also has a light-transmitting hole communicating with the sealed cavity, the light-transmitting hole being provided with a viewing window made of a light-transmitting material;

[0010] A pressure pump is used to blow gas into the sealed cavity;

[0011] A vacuum pump is used to extract the gas from the sealed cavity;

[0012] A standard pressure gauge is used to obtain the gas pressure inside the sealed cavity.

[0013] Pressure gauge calibration equipment includes:

[0014] The pressure chamber has a sealed cavity that can form a seal for housing pressure gauges. The pressure chamber is also provided with a pressure input interface and an electrical interface.

[0015] A pressure pump is used to blow gas into the sealed cavity;

[0016] A vacuum pump is used to extract the gas from the sealed cavity;

[0017] A standard pressure gauge is used to obtain the gas pressure inside the sealed cavity;

[0018] The pressure controller can be connected to the pressure input terminal of the pressure instrument through the pressure input interface, and is used to input pressure to the pressure input terminal and display the magnitude of the input pressure;

[0019] The secondary instrument can be connected to the signal output terminal of the pressure instrument through the electrical interface.

[0020] As a preferred option for pressure gauge calibration equipment, a standard height gauge is used to obtain the gas pressure inside the sealed cavity and output the height data corresponding to the gas pressure.

[0021] As a preferred embodiment of pressure gauge calibration equipment, the pressure chamber includes a pressure chamber body, a sealed cavity disposed within the pressure chamber body, and the pressure chamber body also has an opening communicating with the sealed cavity. The opening is provided with a pressure chamber door, which is capable of closing the opening to seal the sealed cavity.

[0022] As a preferred embodiment of pressure gauge calibration equipment, one end face of the pressure relief chamber is provided with multiple threaded holes, and the pressure relief chamber is connected to the pressure relief chamber door by multiple connecting bolts. All of the multiple connecting bolts pass through the pressure relief chamber door and are threadedly connected to the multiple threaded holes one by one.

[0023] As a preferred embodiment of the pressure gauge calibration equipment, the pressure chamber further includes two end plates respectively disposed at both ends of the pressure chamber body, and both end plates are used to support the pressure chamber on the ground.

[0024] As a preferred embodiment of pressure gauge calibration equipment, the sealed cavity is provided with a mounting base for placing the pressure gauge.

[0025] As a preferred option for pressure gauge calibration equipment, a temperature sensor is also provided inside the sealed cavity, which is used to obtain the temperature inside the sealed cavity.

[0026] As a preferred embodiment of the pressure gauge calibration equipment, the pressure pump is connected to the absolute pressure tank via a first connecting pipe, and the vacuum pump is connected to the absolute pressure tank via a second connecting pipe. The first connecting pipe is equipped with a first shut-off valve, which is used to control the opening and closing of the first connecting pipe. The second connecting pipe is equipped with a second shut-off valve, which is used to control the opening and closing of the second connecting pipe.

[0027] As a preferred option for pressure gauge calibration equipment, the absolute pressure chamber is also provided with a pressure gauge interface, through which the standard pressure gauge is connected to the absolute pressure chamber to obtain the gas pressure inside the sealed cavity.

[0028] The beneficial effects of this utility model are:

[0029] This invention provides a pressure gauge calibration device, including an absolute pressure chamber, a pressure pump, a vacuum pump, and a standard pressure gauge. The absolute pressure chamber has a sealed cavity capable of forming a seal, which is used to house the pressure gauge. The absolute pressure chamber also has a light-transmitting hole communicating with the sealed cavity, and the light-transmitting hole is provided with a viewing window made of light-transmitting material. The pressure pump is used to blow gas into the sealed cavity; the vacuum pump is used to extract gas from the sealed cavity; and the standard pressure gauge is used to obtain the gas pressure inside the sealed cavity. The pressure gauge can be placed in the sealed cavity to form a seal. By blowing gas into the sealed cavity through the pressure pump and extracting gas from the sealed cavity through the vacuum pump, the gas pressure inside the sealed cavity can be adjusted to simulate high-altitude environments at different altitudes. The gas pressure inside the sealed cavity is obtained through the standard pressure gauge, and the altitude corresponding to the current gas pressure inside the sealed cavity can be determined based on the pressure displayed on the standard pressure gauge. In addition, by observing the reading of the pressure gauge through the viewing window and comparing it with the gas pressure obtained by the standard pressure gauge, the pressure gauge can be calibrated.

[0030] This invention also provides another pressure gauge calibration device, including an absolute pressure chamber, a pressure pump, a vacuum pump, a standard pressure gauge, a pressure controller, and a secondary instrument. The absolute pressure chamber has a sealed cavity that can form a seal for placing the pressure gauge. The absolute pressure chamber is also provided with a pressure input interface and an electrical interface. The pressure pump is used to blow gas into the sealed cavity. The vacuum pump is used to extract gas from the sealed cavity. The standard pressure gauge is used to obtain the gas pressure in the sealed cavity. The pressure controller can be connected to the pressure input terminal of the pressure gauge through the pressure input interface to input pressure to the pressure input terminal and display the magnitude of the input pressure. The secondary instrument can be connected to the signal output terminal of the pressure gauge through the electrical interface. The pressure gauge can be placed inside a sealed cavity to form a seal. Gas is blown into the sealed cavity by a pressure pump, and the gas inside the sealed cavity is extracted by a vacuum pump to adjust the gas pressure inside the sealed cavity, thereby simulating high-altitude environments at different altitudes. The gas pressure inside the sealed cavity is obtained through a standard pressure gauge, and the altitude corresponding to the gas pressure inside the sealed cavity can be determined based on the pressure displayed on the standard pressure gauge. In addition, pressure is input to the pressure input terminal of the pressure gauge through a pressure controller, and the pressure provided by the pressure controller is displayed. The detection value of the pressure gauge is output by a secondary instrument. By comparing the pressure provided by the pressure controller with the display value of the secondary instrument, the pressure gauge can be calibrated. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the calibration structure of an aviation absolute pressure gauge in the prior art;

[0032] Figure 2 This is a schematic diagram of the calibration structure of a pressure sensor in the prior art;

[0033] Figure 3 This is a schematic diagram of the structure of the pressure gauge calibration device in this embodiment of the utility model;

[0034] Figure 4 This is a schematic diagram of the first structure of the pressure relief box in this embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the second structure of the pressure relief box in an embodiment of this utility model.

[0036] In the picture:

[0037] 1000. Aircraft absolute pressure gauge; 1100. Atmospheric data testing instrument; 1200. Pressure generator;

[0038] 2000. Atmospheric pressure sensor; 2100. Piston pressure gauge; 2200. Secondary instrument;

[0039] 1. Pressure relief chamber; 11. Viewing window; 12. Pressure relief chamber body; 13. Pressure relief chamber door; 131. Connecting bolts; 14. End plate;

[0040] 101. Sealed cavity; 102. Opening; 103. Pressure input interface; 104. Electrical interface; 105. Pressure gauge interface; 106. Sensor interface; 107. Altimeter interface; 108. Pressure pump interface; 109. Vacuum pump interface;

[0041] 2. Pressure pump; 21. First connecting pipeline; 22. First shut-off valve;

[0042] 3. Vacuum pump; 31. Second connecting pipeline; 32. Second shut-off valve;

[0043] 4. Standard pressure gauge;

[0044] 5. Standard height gauge;

[0045] 6. Secondary instruments. Detailed Implementation

[0046] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0047] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0048] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0049] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0050] Example 1

[0051] In existing technology, the calibration structure for aviation pressure gauges is as follows: a pressure generator is connected to both the aviation pressure gauge to be calibrated and an atmospheric data analyzer serving as a standard instrument. Using the pressure generator as a pressure source, both the aviation pressure gauge and the atmospheric data analyzer simultaneously detect the applied pressure. The measured values ​​are then compared, and calibration is performed. However, this calibration process is completed on the ground, not in a real high-altitude environment. Therefore, the calibrated aviation pressure gauge may still exhibit errors under high-altitude conditions.

[0052] To address the aforementioned issues, this embodiment provides a pressure gauge calibration device, which can be used in the field of pressure gauge calibration technology.

[0053] Reference Figures 3-5 The pressure gauge calibration device in this embodiment includes an absolute pressure chamber 1, a pressure pump 2, a vacuum pump 3, and a standard pressure gauge 4. The absolute pressure chamber 1 has a sealed cavity 101 that can form a seal, which is used to place the pressure gauge. The absolute pressure chamber 1 also has a light-transmitting hole communicating with the sealed cavity 101, and the light-transmitting hole is provided with a viewing window 11 made of light-transmitting material. The pressure pump 2 is used to blow gas into the sealed cavity 101. The vacuum pump 3 is used to extract the gas in the sealed cavity 101. The standard pressure gauge 4 is used to obtain the gas pressure in the sealed cavity 101. A pressure gauge can be placed inside a sealed cavity 101 to form a seal. Gas is blown into the sealed cavity 101 by a pressure pump 2, and the gas is extracted from the sealed cavity 101 by a vacuum pump 3 to adjust the gas pressure inside the sealed cavity 101 to simulate high-altitude environments at different altitudes. The gas pressure inside the sealed cavity 101 is obtained through a standard pressure gauge 4. The altitude corresponding to the gas pressure inside the sealed cavity 101 at this time can be determined based on the pressure displayed by the standard pressure gauge 4. In addition, the reading of the pressure gauge can be observed through the viewing window 11 and compared with the gas pressure obtained by the standard pressure gauge 4 to calibrate the pressure gauge.

[0054] In this embodiment, the pressure instrument is specifically an aviation absolute pressure gauge. Alternatively, it can be any other pressure instrument that can directly display the reading.

[0055] Optionally, the pressure chamber 1 is provided with a pressure pump interface 108 and a vacuum pump interface 109. The pressure pump 2 blows gas into the sealed cavity 101 through the pressure pump interface 108, and the vacuum pump 3 extracts the gas from the sealed cavity 101 through the vacuum pump interface 109.

[0056] Continue to refer to Figures 3-5 Although users can indirectly determine the height corresponding to the gas pressure in the sealed cavity 101 based on the reading of the standard pressure gauge 4, this is cumbersome as it requires looking up the gauge or performing calculations again. To facilitate users in obtaining the height corresponding to the current gas pressure in the sealed cavity 101, the pressure instrument calibration device also includes a standard height gauge 5. The standard height gauge 5 is used to obtain the gas pressure in the sealed cavity 101 and output the height data corresponding to the gas pressure. The specific structure and principle of the standard height gauge 5 are already mature technologies in this field and will not be described in detail here. Optionally, the absolute pressure box 1 is also provided with a height gauge interface 107. The standard height gauge 5 is connected to the absolute pressure box 1 through the height gauge interface 107, specifically, the standard height gauge 5 is connected to the height gauge interface 107 through a corresponding connecting pipe.

[0057] Continue to refer to Figures 3-5 The pressure relief chamber 1 includes a pressure relief chamber body 12, a sealed cavity 101 disposed within the pressure relief chamber body 12, and an opening 102 communicating with the sealed cavity 101. The opening 102 is equipped with a pressure relief chamber door 13, which can close the opening 102 to seal the sealed cavity 101. Pressure gauges can be placed in the sealed cavity 101 through the opening 102. A viewing window 11 is embedded in either the pressure relief chamber body 12 or the pressure relief chamber door 13.

[0058] Continue to refer to Figures 3-5 To ensure a good seal, the pressure relief chamber 12 has multiple threaded holes on one end face. The pressure relief chamber 12 is connected to the pressure relief chamber door 13 by multiple connecting bolts 131. All the connecting bolts 131 pass through the pressure relief chamber door 13 and are threadedly connected to the multiple threaded holes one by one.

[0059] Continue to refer to Figures 3-5 The sealed cavity 101 is provided with a mounting base for placing pressure gauges so as to place the pressure gauges stably.

[0060] Continue to refer to Figures 3-5 A temperature sensor is also installed inside the sealed cavity 101 to obtain the temperature inside the sealed cavity 101, so that the user can know the gas temperature inside the sealed cavity 101 at any time and avoid the temperature affecting the calibration results. Optionally, the absolute pressure box 1 is provided with a sensor interface 106, and the temperature sensor is connected to the sensor interface 106.

[0061] Continue to refer to Figures 3-5Pressure pump 2 is connected to pressure tank 1 via first connecting pipe 21, and vacuum pump 3 is connected to pressure tank 1 via second connecting pipe 31. First connecting pipe 21 is equipped with first shut-off valve 22, which is used to control the opening and closing of first connecting pipe 21. Second connecting pipe 31 is equipped with second shut-off valve 32, which is used to control the opening and closing of second connecting pipe 31. The user can stop pressure pump 2 from blowing gas into sealed cavity 101 by closing first shut-off valve 22, and can stop vacuum pump 3 from extracting gas from sealed cavity 101 by closing second shut-off valve 32.

[0062] Continue to refer to Figures 3-5 The pressure relief chamber 1 is also equipped with a pressure gauge interface 105. A standard pressure gauge 4 is connected to the pressure relief chamber 1 through the pressure gauge interface 105 to obtain the gas pressure in the sealed cavity 101. Specifically, the standard pressure gauge 4 is connected to the pressure gauge interface 105 through a corresponding connecting pipe.

[0063] Continue to refer to Figures 3-5 The pressure relief chamber 1 also includes two end plates 14 respectively disposed at both ends of the pressure relief chamber body 12. Both end plates 14 are used to support the pressure relief chamber on the ground, thereby providing stable support. Optionally, the pressure gauge interface 105, sensor interface 106, altimeter interface 107, pressure pump interface 108, and vacuum pump interface 109 are all disposed on one of the end plates 14 to facilitate the connection between the pressure relief chamber 1 and other structures.

[0064] Example 2

[0065] In existing technology, the calibration structure for pressure sensors is as follows: a piston pressure gauge, specifically a gas piston pressure gauge or a liquid piston pressure gauge, serves as the pressure source. The measuring end of the atmospheric pressure sensor is connected to the test port of the piston pressure gauge. A secondary instrument is connected to the atmospheric pressure sensor via wires to display the measurement data of the atmospheric pressure sensor. This measurement data can be compared with the output pressure of the piston pressure gauge for calibration. However, the above calibration process is completed on the ground, not in a real high-altitude environment. Therefore, the calibrated airborne atmospheric pressure sensor may still have errors in a high-altitude environment.

[0066] To address the aforementioned issues, this embodiment provides another pressure gauge calibration device, which can be used in the field of pressure gauge calibration technology.

[0067] Reference Figures 3-5The pressure gauge calibration device in this embodiment includes an absolute pressure chamber 1, a pressure pump 2, a vacuum pump 3, a standard pressure gauge 4, a pressure controller, and a secondary instrument 6. The absolute pressure chamber 1 has a sealed cavity 101 that can form a seal, which is used to place the pressure gauge. The absolute pressure chamber 1 is also provided with a pressure input interface 103 and an electrical interface 104. The pressure pump 2 is used to blow gas into the sealed cavity 101. The vacuum pump 3 is used to extract the gas from the sealed cavity 101. The standard pressure gauge 4 is used to obtain the gas pressure in the sealed cavity 101. The pressure controller can be connected to the pressure input terminal of the pressure gauge through the pressure input interface 103 to input pressure to the pressure input terminal and display the magnitude of the input pressure. The secondary instrument 6 can be connected to the signal output terminal of the pressure gauge through the electrical interface 104. A pressure gauge can be placed inside a sealed cavity 101 to form a seal. Gas is blown into the sealed cavity 101 by a pressure pump 2, and the gas is extracted from the sealed cavity 101 by a vacuum pump 3 to adjust the gas pressure inside the sealed cavity 101 to simulate high-altitude environments at different altitudes. The gas pressure inside the sealed cavity 101 is obtained through a standard pressure gauge 4, and the altitude corresponding to the gas pressure inside the sealed cavity 101 can be determined based on the pressure displayed by the standard pressure gauge 4. In addition, pressure is input to the pressure input terminal of the pressure gauge through a pressure controller, and the pressure provided by the pressure controller is displayed. The detection value of the pressure gauge is output by a secondary instrument 6. By comparing the pressure provided by the pressure controller with the display value of the secondary instrument 6, the pressure gauge can be calibrated.

[0068] In this embodiment, the pressure instrument is specifically an aviation atmospheric pressure sensor. Alternatively, it can be any other pressure instrument that requires pressure to be provided by a pressure controller and for the secondary instrument 6 to output the detection value.

[0069] Example 3

[0070] This embodiment provides yet another pressure gauge calibration device, referring to... Figures 3-5Specifically, the pressure gauge calibration device provided in this embodiment includes an absolute pressure chamber 1, a pressure pump 2, a vacuum pump 3, a standard pressure gauge 4, a pressure controller, and a secondary instrument 6. The absolute pressure chamber 1 has a sealed cavity 101 that can form a seal, which is used to place the pressure gauge. The absolute pressure chamber 1 is also provided with a pressure input interface 103 and an electrical interface 104. The absolute pressure chamber 1 also has a light-transmitting hole communicating with the sealed cavity 101, which is provided with a viewing window 11 made of light-transmitting material. The pressure pump 2 is used to blow gas into the sealed cavity 101. The vacuum pump 3 is used to extract gas from the sealed cavity 101. The standard pressure gauge 4 is used to obtain the gas pressure in the sealed cavity 101. The pressure controller can be connected to the pressure input terminal of the pressure gauge through the pressure input interface 103 to input pressure to the pressure input terminal and display the magnitude of the input pressure. The secondary instrument 6 can be connected to the signal output terminal of the pressure gauge through the electrical interface 104.

[0071] The pressure instrument calibration device in this embodiment can calibrate both aviation absolute pressure gauges and aviation atmospheric pressure sensors. Different calibration methods are used when calibrating different pressure instruments, thus providing the versatility of the pressure instrument calibration device.

[0072] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. Pressure gauge calibration apparatus, characterized in that, The absolute pressure box (1) has a sealed cavity (101) capable of forming a seal, which is used to place a pressure instrument; the absolute pressure box (1) also has a light transmission hole in communication with the sealed cavity (101), and the light transmission hole is provided with a window (11) made of light transmission material; A pressure pump (2) is used to blow gas into the sealed cavity (101); A vacuum pump (3) is used to extract gas in the sealed cavity (101); A standard pressure gauge (4) is used to obtain the gas pressure in the sealed cavity (101). The absolute pressure box (1) has a sealed cavity (101) capable of forming a seal, which is used to place a pressure instrument, and the absolute pressure box (1) is also provided with a pressure input interface (103) and an electrical interface (104); 2. Pressure instrument calibration apparatus, characterized in that, A pressure pump (2) is used to blow gas into the sealed cavity (101); A vacuum pump (3) is used to extract gas in the sealed cavity (101); A standard pressure gauge (4) is used to obtain the gas pressure in the sealed cavity (101); A pressure controller can be connected with the pressure input end of the pressure instrument through the pressure input interface (103), used to input pressure to the pressure input end and display the size of the input pressure; A secondary instrument (6) can be connected with the signal output end of the pressure instrument through the electrical interface (104). A standard height gauge (5) is used to obtain the gas pressure in the sealed cavity (101) and output the height data corresponding to the gas pressure. The absolute pressure box (1) includes an absolute pressure box body (12), the sealed cavity (101) is arranged in the absolute pressure box body (12), and the absolute pressure box body (12) also has an opening (102) in communication with the sealed cavity (101); the opening (102) is provided with an absolute pressure box door (13), and the absolute pressure box door (13) can close the opening (102) to form a seal for the sealed cavity (101).

3. Pressure gauge calibration apparatus according to claim 1 or 2, characterized in that A plurality of threaded holes are arranged on one end face of the absolute pressure box body (12), a plurality of connecting bolts (131) are connected between the absolute pressure box body (12) and the absolute pressure box door (13), the plurality of connecting bolts (131) all pass through the absolute pressure box door (13) and are threadedly connected with the plurality of threaded holes in a one-to-one correspondence.

4. Pressure gauge calibration apparatus according to claim 1 or 2, characterized in that The absolute pressure box (1) also includes two end plates (14) respectively arranged at both end portions of the absolute pressure box body (12), and the two end plates (14) are both used to be supported on the ground.

5. The pressure gauge calibration apparatus of claim 4, wherein, The sealed cavity (101) is provided with a mounting seat for placing a pressure instrument.

6. The pressure gauge calibration apparatus of claim 4, wherein, The sealed cavity (101) is also provided with a temperature sensor for obtaining the temperature in the sealed cavity (101).

7. Pressure gauge calibration apparatus according to claim 1 or 2, characterized in that ​ 8. Pressure gauge calibration apparatus according to claim 1 or 2, characterized in that ​ 9. Pressure gauge calibration apparatus according to claim 1 or 2, characterized in that The pressure pump (2) is connected with the absolute pressure tank (1) through a first connecting pipeline (21), the vacuum pump (3) is connected with the absolute pressure tank (1) through a second connecting pipeline (31), the first connecting pipeline (21) is provided with a first stop valve (22), the first stop valve (22) is used for controlling the on-off of the first connecting pipeline (21), the second connecting pipeline (31) is provided with a second stop valve (32), and the second stop valve (32) is used for controlling the on-off of the second connecting pipeline (31).

10. Pressure gauge calibration apparatus according to claim 1 or 2, characterized in that The absolute pressure tank (1) is also provided with a pressure gauge interface (105), and the standard pressure gauge (4) is connected with the absolute pressure tank (1) through the pressure gauge interface (105) to obtain the gas pressure in the sealed cavity (101).

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