A pressure sensor calibration system and method based on a small, dismountable shock tube

Abstract

The application belongs to the technical field of pressure measurement, and discloses a pressure sensor calibration system and method based on a small detachable shock tube, wherein the shock tube comprises a front end cover, a shock tube shell and a rear end cover, the front end cover and the rear end cover are respectively arranged at two ends of the shock tube shell, the front end cover is adapted to the assembly of a pressure sensor to be measured, and the rear end cover is provided with an air inlet; the shock tube shell is spliced by at least two pipes with different lengths, flanges are arranged at two ends of each pipe, the connected pipes are connected through adjacent flanges, sealing structures are arranged between the flanges, a pipe connected with one end of the front end cover is a low-pressure chamber, and the other pipes together form a high-pressure chamber, and the low-pressure chamber and the high-pressure chamber are separated by a diaphragm. The application can be used for dynamic pressure calibration of various pressure sensors, and has important engineering application value; the method can be applied to rapid design and system establishment of various shock tubes, and stable and controllable shock excitation is generated.

Description

Technical Field

[0001] This invention belongs to the field of pressure measurement technology, and relates to a pressure sensor calibration system, specifically a pressure sensor calibration system and method based on a small, detachable shock tube. Background Technology

[0002] Pressure sensor calibration often employs shock tubes. Traditional shock tubes, with their metal housings, are bulky, expensive, heavy, and difficult to modify. To meet the calibration requirements of various pressure sensors, such as reflected pressure and free-field pressure sensors, the specific dimensions of the shock tube, especially the length ratio of the high-pressure and low-pressure sections, frequently change depending on the specifications and dimensions of the sensor being calibrated. Therefore, current solutions for shock tube calibration of pressure sensors suffer from the problems of high shock tube housing costs, bulky size, and operational difficulties. Furthermore, the current shock tube length is not adjustable, and there is no reasonable adjustment scheme. For dynamic calibration of pressure sensors below 1 MPa, the use of existing shock tube calibration systems is highly wasteful and inconvenient to operate. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a pressure sensor calibration system and method based on a small, detachable shock tube. This system is small in size, lightweight, and can be disassembled in multiple sections, making it convenient and quick for single-person operation. It is highly suitable for high-precision dynamic calibration and verification of small pressure sensors below 1 MPa.

[0004] The technical solution of the present invention is as follows:

[0005] A small, multi-segment detachable shock tube includes a front end cover, a shock tube housing, and a rear end cover. The front end cover and the rear end cover are respectively located at both ends of the shock tube housing. The front end cover is adapted to assemble the pressure sensor under test, and the rear end cover has an air inlet. The shock tube housing is spliced ​​from at least two pipe segments of different lengths. Each pipe segment has flanges at both ends. Connected pipe segments are connected through adjacent flanges, and a sealing structure is provided between the flanges. The pipe connected to one end of the front end cover is the low-pressure chamber, and the other pipe segments together form the high-pressure chamber. The low-pressure chamber and the high-pressure chamber are separated by a diaphragm. Matching pipes of different lengths allows for rapid modification of the length ratio between the high-pressure chamber and the low-pressure chamber.

[0006] Furthermore, the shock tube shell is made of rigid polyvinyl chloride, and the wall thickness of the shock tube shell is calculated according to the strength verification calculation method:

[0007]

[0008] In the formula, δ is the calculated thickness of the shock tube; p c To calculate the pressure, i.e., the theoretical maximum pressure inside the shock tube; D i [σ] is the inner diameter of the shock tube. tφ represents the allowable stress of the shock tube shell material at the design temperature; φ is the weld joint coefficient.

[0009] Furthermore, the length of the low-pressure chamber of the shock tube casing is not less than the distance from which the planar shock wave forms after the diaphragm ruptures, specifically:

[0010]

[0011] The membrane rupture diameter is preset, the planar shock wave formation distance is obtained based on the membrane rupture diameter, and a margin is added to the planar shock wave formation distance as the low-pressure chamber length of the shock tube shell.

[0012] Furthermore, it also includes a pressure ring, a support frame, and a support base. The pressure ring presses and fixes the shock tube housing onto the support frame at both ends. The support frame and support base are fixed, and vibration damping blocks are placed between the support frame and support base.

[0013] Furthermore, the diaphragm is made of annealed aluminum foil, and the thickness of the annealed aluminum foil is selected according to the pressure range of the sensor being calibrated.

[0014] A pressure sensor calibration system based on a small, multi-segment detachable shock tube includes an air compressor, a solenoid valve, a shock tube, a sensor to be calibrated, a signal conditioner, a data acquisition system, and a host computer. The shock tube is a small, multi-segment detachable shock tube as described above. The air compressor is connected to the high-pressure chamber of the shock tube via the solenoid valve, the sensor to be calibrated is connected to the low-pressure chamber of the shock tube, the signal interface of the sensor to be calibrated is connected to the signal conditioner, the signal conditioner is connected to the data acquisition system, the data acquisition system is connected to the host computer, and the host computer contains pressure sensor calibration software.

[0015] Furthermore, it also includes a vibration sensor and a control system. The vibration sensor monitors the vibration of the shock tube, and the vibration sensor signal is connected to the control system. The control system controls the solenoid valve. When the vibration sensor emits a vibration signal higher than the set value, the control system shuts off the solenoid valve.

[0016] A method for using a pressure sensor calibration system based on a small, multi-segment detachable shock tube, comprising the following steps:

[0017] S1: Based on CFD technology or theoretical calculations, design the lengths of the high-pressure chamber and low-pressure chamber required for the shock tube;

[0018] S2: Select shock tubes of different lengths and splice them according to the required length ratio of the high-pressure chamber and the low-pressure chamber;

[0019] S3: Install and tighten each section of the shock tube pipe, install the sensor to be calibrated at the adapter, and then tighten it to the rear cover;

[0020] S4: According to the required pressure range to be calibrated, place the diaphragm between the high and low pressure chambers;

[0021] S5: Open the solenoid valve, and the air compressor automatically fills the high-pressure chamber of the shock tube with air. The filling speed is controlled by the air compressor.

[0022] S6: During inflation, ensure that the pressure inside the pipeline does not exceed the safe allowable stress of the pipeline. If the pressure is found to exceed the required range, shut off the inflation pipeline in time.

[0023] S7: When the pressure difference between high and low reaches the required pressure, the diaphragm ruptures, and a pressure step is generated between the high-pressure chamber and the low-pressure chamber, forming a shock wave. The pressure signal is sensed by the calibration sensor, which generates a corresponding electrical signal and transmits it to the signal conditioner. The signal conditioner outputs the conditioned signal to the data acquisition system and records the data on the host computer.

[0024] The advantages of this invention are:

[0025] The simplified shock tube of this invention has advantages such as small size, light weight, multi-section disassembly and assembly, and convenient operation. It can be used for dynamic pressure calibration of various pressure sensors below 1 MPa, and has significant engineering application value. In the field of dynamic pressure sensor calibration, the design method of this invention can be applied to the rapid design and system construction of various shock tubes, generating stable and controllable shock excitation, which greatly promotes the dynamic calibration of various pressure sensors. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this invention, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of the simple shock tube of the present invention, which is small and can be disassembled in multiple sections.

[0028] Figure 2 yes Figure 1 Side view.

[0029] Figure 3 This is a schematic diagram of the installation of the pressure gauge in the shock tube of the present invention.

[0030] Figure 4 This is a three-dimensional design drawing of the simple shock tube of the present invention, which is small and can be disassembled in multiple sections.

[0031] Figure 5 This is a block diagram of the shock tube dynamic pressure calibration system based on the present invention.

[0032] Wherein: 1—Front end cover, 2—Pressure gauge, 3—Shock tube housing, 4—Flange, 5—Rubber gasket, 6—Fixing bolts and nuts, 7—Pressure ring, 8—Support frame, 9—Rear end cover, 10—Support base, 11—Angle bracket, 12—Air compressor, 13—Solenoid valve, 14—Shock tube, 15—Sensor under calibration, 16—Signal conditioner, 17—Data acquisition system, 18—Host computer, 19—Vibration sensor, 20—Control system, 21—Shaft sleeve, 22—Sealing ring, 23—Mounting ring. Detailed Implementation

[0033] This section describes embodiments of the present invention, used to explain and illustrate the technical solutions of the present invention. Unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0034] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating directions or positional relationships, are based on the orientation or positional relationships in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or case referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include more than one of those features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integrated connections; they can refer to mechanical connections or point connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Example 1

[0037] A small, multi-segment detachable shock tube includes a front cover 1, a shock tube housing 3, and a rear cover 9. The front cover 1 and the rear cover 9 are respectively located at both ends of the shock tube housing 3. The front cover 1 is adapted to the assembly of the pressure sensor to be measured, and the rear cover 9 is provided with an air inlet. The shock tube housing 3 is spliced ​​from at least two pipes of different lengths. Each pipe segment has flanges 4 at both ends. Connected pipes are connected through adjacent flanges 4. A sealing structure is provided between the flanges 4. The pipe connected to one end of the front cover 1 is the low-pressure chamber, and the other pipes together form the high-pressure chamber. The low-pressure chamber and the high-pressure chamber are separated by a diaphragm. Matching pipes of different lengths allows for rapid modification of the length ratio between the high-pressure chamber and the low-pressure chamber.

[0038] The shock tube housing 3 is made of rigid polyvinyl chloride, and the wall thickness of the shock tube housing 3 is calculated according to the strength verification calculation method:

[0039]

[0040] In the formula, δ is the calculated thickness of the shock tube; p c To calculate the pressure, i.e., the theoretical maximum pressure inside the shock tube; D i [σ] is the inner diameter of the shock tube. t φ represents the allowable stress of the shock tube shell material at the design temperature; φ is the weld joint coefficient.

[0041] The ratio of the high-pressure chamber length to the low-pressure chamber length of the shock tube can be estimated using Equation 2.

[0042]

[0043] In the formula, X is the ratio of the tube length of the high-pressure chamber to that of the low-pressure chamber, and Ma is the Mach number of the shock wave inside the tube.

[0044] The length of the low-pressure chamber of the shock tube housing 3 is not less than the distance from which the planar shock wave forms after the diaphragm ruptures, specifically:

[0045]

[0046] The membrane rupture diameter is preset, and the planar shock wave formation distance is obtained based on the membrane rupture diameter. An extra length is added to the planar shock wave formation distance as the low-pressure chamber length of the shock tube shell 3.

[0047] It also includes a pressure ring 7, a support frame 8 and a support base 10. The pressure ring 7 presses and fixes the shock tube housing 3 onto the support frame 8 at both ends. The support frame 8 and the support base 10 are fixed, and a damping block is also placed between the support frame 8 and the support base 10.

[0048] The diaphragm is made of annealed aluminum foil, and the thickness of the annealed aluminum foil is selected according to the pressure range of the sensor 15 being calibrated.

[0049] A pressure sensor calibration system based on a small, multi-segment detachable shock tube includes an air compressor 12, a solenoid valve 13, a shock tube 14, a sensor to be calibrated 15, a signal conditioner 16, a data acquisition system 17, and a host computer 18. The shock tube 14 is a small, multi-segment detachable shock tube as described above. The air compressor 12 is connected to the high-pressure chamber of the shock tube 14 through the solenoid valve 13. The sensor to be calibrated 15 is connected to the low-pressure chamber of the shock tube 14. The signal interface of the sensor to be calibrated 15 is connected to the signal conditioner 16. The signal conditioner 16 is connected to the data acquisition system 17. The data acquisition system 17 is connected to the host computer 18. The host computer 18 contains pressure sensor calibration software.

[0050] It also includes a vibration sensor 19 and a control system 20. The vibration sensor 19 monitors the vibration of the shock tube 14 and the vibration sensor 19 is connected to the control system 20. The control system 20 controls the solenoid valve 13. After the vibration sensor 19 emits a vibration signal higher than the set value, the control system 20 shuts off the solenoid valve 13.

[0051] A method for using a pressure sensor calibration system based on a small, multi-segment detachable shock tube, comprising the following steps:

[0052] S1: Based on CFD technology or theoretical calculations, design the required high- and low-pressure chamber length ratio for the shock tube;

[0053] S2: Select shock tubes of different lengths for splicing according to the required ratio of high and low pressure chamber lengths;

[0054] S3: Install and tighten each section of the shock tube pipe, install the sensor to be calibrated 15 at the adapter, and then tighten it to the rear cover 9;

[0055] S4: According to the required pressure range to be calibrated, place the diaphragm between the high and low pressure chambers;

[0056] S5: Open the solenoid valve 13, and the air compressor 12 automatically fills the high-pressure chamber of the shock tube 14 with air. The filling speed is controlled by the air compressor 12.

[0057] S6: During inflation, ensure that the pressure inside the pipeline does not exceed the safe allowable stress of the pipeline. If the pressure is found to exceed the required range, shut off the inflation pipeline in time.

[0058] S7: When the pressure difference between high and low reaches the required pressure, the diaphragm ruptures, and a pressure step occurs between the high-pressure chamber and the low-pressure chamber, forming a shock wave. The pressure sensor 15 senses the pressure signal and generates a corresponding electrical signal, which is transmitted to the signal conditioner 16. The signal conditioner 16 outputs the conditioned signal to the data acquisition system 17 and records the data to the host computer 18.

[0059] Example 2:

[0060] A design method for a small, multi-segment detachable and simple shock tube and calibration system, wherein the shock tube comprises:

[0061] 1. Front cover; 2. Pressure gauge; 3. Shock tube housing; 4. Flange; 5. Rubber gasket; 6. Fixing bolts and nuts; 7. Pressure ring; 8. Support frame; 9. Rear cover; 10. Support base; 11. Angle bracket, wherein:

[0062] The shock tube housing 3 is made of rigid polyvinyl chloride (PVC-U), and the wall thickness is obtained based on the strength verification theory.

[0063] By determining the formation distance of the planar shock wave after membrane rupture using CFD simulation technology, the minimum length requirement of the low-pressure chamber of the shock tube shell 3 can be obtained.

[0064] The shock tube housing 3 is spliced ​​together from multiple pipes of different lengths. Each pipe has a flange 4 at both ends. After the flanges 4 are sealed with rubber gaskets 5, they are fixed by fixing bolts and nuts 6. Matching pipes of different lengths can quickly modify the length ratio of the high and low pressure chambers.

[0065] The shock tube housing 3 is fixed to the support frame 8 by a pressure ring 7, and the pressure ring 7 and the support frame 8 are fixed together by T-bolts and nuts.

[0066] The support frame 8, the corner bracket 11, and the support base 10 are fixed together by T-bolts and nuts.

[0067] The high-pressure chamber sidewall of the shock tube housing 3 is equipped with a pressure gauge 2, which is used to monitor the pressure change in the high-pressure chamber during inflation / deflation.

[0068] The front end cover 1 and rear end cover 9 are made of general-purpose 304 stainless steel, ensuring a certain level of impact resistance and rigidity. To accommodate various pressure sensors, multiple mounting holes for reflective pressure sensors and free-field dynamic pressure sensors are provided at the end covers. The sensors are fixed to the end covers via adapters. Another advantage of using adapters is that they can attenuate the transmission of stress waves, reducing the impact of vibration on the sensors.

[0069] Based on the aforementioned simplified shock tube, a dynamic pressure calibration system for the shock tube is designed, characterized in that the calibration system comprises:

[0070] Air compressor 12, solenoid valve 13, shock tube 14, sensor under test 15, signal conditioner 16, data acquisition system 17, host computer 18, vibration sensor 19, control system 20, wherein:

[0071] The solenoid valve 13 is installed between the air compressor 12 and the shock tube 14 and is used to control the on / off switch of the high-pressure chamber inflation.

[0072] The vibration sensor 19 is mounted on the support base 10 to sense the minute mechanical vibration generated when the shock tube 14 breaks the membrane, and transmits an on / off signal to the control system 20. The control system 20 generates a TTL signal through the internal conditioning circuit.

[0073] The solenoid valve 13 is controlled by a TTL signal provided by the control system 20, which realizes the function of automatically shutting off the inflation after the shock tube membrane is broken.

[0074] The sensor 15 being calibrated is mounted on the end face of the shock tube 14 and is connected in sequence to the signal conditioner 16, the data acquisition system 17, and the host computer 18 via lead wires, for acquiring and recording the output waveform of the sensor.

[0075] The control system 20 has a remote control function, which can be driven by remote commands to control the opening and closing of the solenoid valve 13.

[0076] Based on the aforementioned shock tube dynamic pressure calibration system, a dynamic pressure calibration method is proposed, comprising the following steps:

[0077] Step 1: Based on CFD technology or theoretical calculations, design the required range of high and low pressure chamber length ratios for the shock tube;

[0078] Step 2: Select shock tubes of different lengths and splice them according to the required ratio of high and low pressure chamber lengths;

[0079] Step 3: Install and tighten each section of the shock tube pipe, install the sensor to be calibrated 15 at the adapter, and then tighten it to the rear end cover 9;

[0080] Step 4: Depending on the required pressure range, use annealed aluminum foil sandwiched between the high and low pressure chambers in the flange;

[0081] Step 5: Open the solenoid valve 13, and the air compressor 12 will automatically fill the high-pressure chamber of the shock tube 14 with air. The filling speed is controlled by the air compressor 12.

[0082] Step 6: During the inflation process, observe pressure gauge 2 to ensure that the pressure in the pipeline does not exceed the safe allowable stress of the pipeline. If the pressure is found to exceed the required range, send a command from the remote end to the control system 20 in time, and the solenoid valve 13 will close the inflation pipeline.

[0083] Step 7: When the pressure difference between high and low reaches the required pressure, the aluminum foil breaks, and a pressure step occurs between the high-pressure chamber and the low-pressure chamber, forming a shock wave. The pressure sensor 15 senses the pressure signal and generates a corresponding electrical signal, which is transmitted to the signal conditioner 16. The signal conditioner 16 outputs the conditioned signal to the data acquisition system 17 and records the data to the host computer 18.

[0084] It also includes step 8: after opening the vent valve and venting the gas in the tube, open the diaphragm section, remove the broken aluminum foil, and remove the remaining aluminum foil fragments in the tube;

[0085] It also includes step 9: shut down all instruments in the calibration system and disconnect the power.

[0086] The thickness of the annealed aluminum foil in step 4 is selected according to the required pressure range.

[0087] In step 5, the inflation speed should be within a safe and controllable range.

[0088] In step 5, the allowable safety stress is specifically 1 MPa.

[0089] Example 3:

[0090] The shock tube design method is as follows:

[0091] Combination Figures 1-4 The shock tube shell 3 is made of rigid polyvinyl chloride (PVC-U), and its wall thickness is determined according to the pressure strength verification method.

[0092]

[0093] In the formula, δ is the calculated thickness of the shock tube; p c To calculate the pressure, i.e., the theoretical maximum pressure inside the shock tube; D i [σ] is the inner diameter of the shock tube. t φ represents the allowable stress of the shock tube shell material at the design temperature; φ is the weld joint coefficient.

[0094] The ratio of the high-pressure chamber length to the low-pressure chamber length of the shock tube can be estimated using Equation 2.

[0095]

[0096] In the formula, X is the ratio of the tube length of the high-pressure chamber to that of the low-pressure chamber, and Ma is the Mach number of the shock wave inside the tube.

[0097] The length of the low-pressure chamber of the shock tube was determined by CFD simulation to determine the formation distance of the planar shock wave after the membrane was ruptured. The formation distance of the planar shock wave under different membrane rupture diameters is shown in Table 1. The length of the low-pressure chamber is not less than the sum of 200 mm and the distance between the sensor sensitive surface and the rear cover 9.

[0098] Table 1. Planar shock wave formation distance under different membrane rupture diameters

[0099]

[0100] The shock tube housing 3 is composed of multiple pipe sections of varying lengths, each with a flange 4 at both ends. The flanges 4 are sealed to each other using rubber gaskets 5. The inner diameter of the gasket is larger than the inner diameter of the pipe. In the jacketed section, the inner diameter of the gasket is the same as the diameter of the aluminum foil, while its outer diameter is similar to that of the flange. To ensure installation strength, 6 to 10 sets of fixing bolts and nuts 6 are used to tightly secure the flanges 4 and gaskets 5.

[0101] Both the support frame 8 and the support base 10 are made of 4040C type industrial aluminum profile. The pressure ring 7 has holes at both ends, and the shock tube housing 3 is pressed and fixed on the support frame 8 by T-bolts and nuts. The support frame 8 and the support base 10 are fixed by angle brackets 11 and bolts and nuts. A damping block is also placed between the support frame 8 and the support base 10 to reduce the vibration generated during the membrane breaking.

[0102] The high-pressure chamber sidewall of the shock tube housing 3 has an opening, and an installation ring 23 is fitted at the opening. Two sealing rings 22 are installed in the groove of the installation ring 23 for air gap sealing and clearance fit between the installation ring 23 and the shock tube housing 3. The bushing 21 is welded to the installation ring 23, and the pressure gauge 2 is fixed to the bushing 21 by threads. The pressure gauge 2 is used to monitor the pressure change in the high-pressure chamber during filling / defilling.

[0103] The front end cover 1 and rear end cover 9 are made of general-purpose 304 stainless steel to ensure a certain level of impact resistance and rigidity. To accommodate various pressure sensors, multiple mounting holes for reflective pressure sensors and free-field dynamic pressure sensors are provided at the end covers. The sensors are fixed to the end covers via adapters. Another advantage of using adapters is that they can attenuate the transmission of stress waves, reducing the impact of vibration on the sensors.

[0104] Example 4

[0105] Combination Figure 4 This paper describes the dynamic pressure calibration system for shock tubes.

[0106] The solenoid valve 13 is installed between the air compressor 12 and the shock tube 14 to control the on / off switch of the high-pressure chamber inflation. The vibration sensor 19 is installed on the support base 10. The vibration sensor 19 is designed based on the principle that the guide needle is switched on / off when the vibration shaft is vibrated. It is used to sense the slight mechanical vibration generated when the shock tube 14 breaks the membrane and transmits the on / off signal to the control system 20. The control system 20 generates a TTL signal through its internal conditioning circuit. The solenoid valve 13 is controlled by the TTL signal provided by the control system 20 to realize the function of automatically shutting off inflation after the shock tube breaks the membrane.

[0107] The control system 20 has a remote control function, which can be driven by a remote end to control the opening and closing of the solenoid valve 13 by sending commands.

[0108] The sensor 15 being calibrated is mounted on the end face of the shock tube 14 and is connected in sequence to the signal conditioner 16, the data acquisition system 17, and the host computer 18 via lead wires, for acquiring and recording the output waveform of the sensor.

[0109] During operation, the solenoid valve 13 is energized and opened, and the air compressor 12 fills the shock tube 14 with air. When the pressure difference between the high and low pressure chambers reaches the preset pressure, the aluminum foil in the jacket section ruptures. The pressure sensor senses the pressure signal and generates a corresponding electrical signal, which is transmitted to the signal conditioner 16. The signal conditioner 16 outputs the conditioned signal to the data acquisition system 17 and records the data to the host computer 18. At the same time, the vibration generated by the rupture causes the guide pin of the vibration sensor 19 to disconnect. The control system 20 receives the switching signal of the vibration sensor 19 and converts the switching signal into a TTL electrical signal, which is transmitted to the solenoid valve 13 to close it. At this time, the air filling in the tube stops.

[0110] Example 5

[0111] Based on the aforementioned shock tube dynamic pressure calibration system, a dynamic pressure calibration method is proposed, comprising:

[0112] Step 1: Design the required high-low pressure chamber length ratio range for the shock tube based on CFD technology or Equation 1;

[0113] Step 2: Select shock tubes of different lengths and splice them according to the required ratio of high and low pressure chamber lengths. The length of the low pressure chamber must not be less than 200mm plus the sum of the distance between the sensitive surface of the sensor 15 and the rear cover 9.

[0114] Step 3: Install and tighten each section of the shock tube pipe, install the sensor to be calibrated 15 at the adapter, and then tighten it to the rear end cover 9;

[0115] Step 4: Select a suitable annealed aluminum foil and sandwich it between the high and low pressure chambers according to the required pressure range. Generally, the aluminum foil thickness is selected from 0.05mm to 0.25mm.

[0116] Step 5: Open the solenoid valve 13, and the air compressor 12 will automatically fill the high-pressure chamber of the shock tube 14 with air. The filling speed is controlled by the air compressor 12. Adjust the air output adjustment valve of the air compressor 12 to keep the filling speed within a safe and controllable range.

[0117] Step 6: During the inflation process, observe pressure gauge 2 to ensure that the pressure in the pipeline does not exceed 1MPa. If the pressure is found to exceed the required range, send a command to the control system 20 from the remote end in time, and the solenoid valve 13 will close the inflation pipeline.

[0118] Step 7: When the pressure difference between high and low reaches the required pressure, the aluminum foil breaks, and a pressure step occurs between the high-pressure chamber and the low-pressure chamber, forming a shock wave. The pressure signal is sensed by the calibration sensor 15, which generates a corresponding electrical signal and transmits it to the signal conditioner 16. The signal conditioner 16 outputs the conditioned signal to the data acquisition system 17 and records the data to the host computer 18.

[0119] Step 8: Open the vent valve to release the gas in the tube, then open the diaphragm section, remove the broken aluminum foil, and clean up any remaining aluminum foil fragments in the tube;

[0120] Step 9: Turn off all instruments in the calibration system and disconnect the power.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A small, multi-segment detachable shock tube, characterized in that, It includes a front cover (1), a shock tube housing (3) and a rear cover (9). The front cover (1) and the rear cover (9) are respectively located at both ends of the shock tube housing (3). The front cover (1) is adapted to the assembly of the pressure sensor to be measured, and the rear cover (9) is provided with an air inlet. The shock tube housing (3) is spliced ​​from at least two pipes of different lengths. Each pipe has a flange (4) at both ends. The connected pipes are connected through adjacent flanges (4). A sealing structure is provided between the flanges (4). The pipe connected to one end of the front cover (1) is the low-pressure chamber, and the other pipes together are the high-pressure chamber. The low-pressure chamber and the high-pressure chamber are separated by a diaphragm. By matching pipes of different lengths, the length ratio of the high-pressure chamber and the low-pressure chamber can be quickly modified.

2. The small, multi-segment detachable shock tube according to claim 1, characterized in that, The shock tube shell (3) is made of rigid polyvinyl chloride, and the wall thickness of the shock tube shell (3) is calculated according to the strength verification calculation method: In the formula, δ is the calculated thickness of the shock tube; p c To calculate the pressure, i.e., the theoretical maximum pressure inside the shock tube; D i [σ] is the inner diameter of the shock tube. t φ represents the allowable stress of the shock tube shell material at the design temperature; φ is the weld joint coefficient.

3. A small, multi-segment detachable shock tube according to claim 1, characterized in that, The length of the low-pressure chamber of the shock tube housing (3) is not less than the distance from which the planar shock wave forms after the diaphragm ruptures, specifically: The membrane rupture diameter is preset, and the planar shock wave formation distance is obtained based on the membrane rupture diameter. An extra length is added to the planar shock wave formation distance as the low-pressure chamber length of the shock tube shell (3).

4. A small, multi-segment detachable shock tube according to claim 1, characterized in that, It also includes a pressure ring (7), a support frame (8) and a support seat (10). The pressure ring (7) presses and fixes the shock tube housing (3) onto the support frame (8) at both ends. The support frame (8) and the support seat (10) are fixed together, and a damping block is also placed between the support frame (8) and the support seat (10).

5. A small, multi-segment detachable shock tube according to claim 1, characterized in that, The diaphragm is made of annealed aluminum foil, and the thickness of the annealed aluminum foil is selected according to the pressure range of the sensor (15) being calibrated.

6. A pressure sensor calibration system based on a small, detachable shock tube, comprising an air compressor (12), a solenoid valve (13), a shock tube (14), a sensor to be calibrated (15), a signal conditioner (16), a data acquisition system (17), and a host computer (18); the shock tube (14) is a small, multi-segment detachable shock tube as described in any one of claims 1-5; characterized in that, The air compressor (12) is connected to the high-pressure chamber of the shock tube (14) via the solenoid valve (13), the sensor to be calibrated (15) is connected to the low-pressure chamber of the shock tube (14), the signal interface of the sensor to be calibrated (15) is connected to the signal conditioner (16), the signal conditioner (16) is connected to the data acquisition system (17), the data acquisition system (17) is connected to the host computer (18), and the host computer (18) is equipped with pressure sensor calibration software.

7. A pressure sensor calibration system based on a small, detachable shock tube according to claim 6, characterized in that, It also includes a vibration sensor (19) and a control system (20). The vibration sensor (19) monitors the vibration of the shock tube (14). The vibration sensor (19) is connected to the control system (20). The control system (20) controls the solenoid valve (13). After the vibration sensor (19) emits a vibration signal higher than the set value, the control system (20) shuts off the solenoid valve (13).

8. A pressure sensor calibration method based on a small, detachable shock tube, using a pressure sensor calibration system based on a small, multi-segment detachable shock tube as described in claim 6 or 7, characterized in that, Includes the following steps: S1: Based on CFD technology or theoretical calculations, design the lengths of the high-pressure chamber and low-pressure chamber of the shock tube; S2: Based on the length ratio of the high-pressure chamber to the low-pressure chamber, select shock tubes of different lengths for splicing; S3: Install the shock tube pipe and tighten it. Install the sensor to be calibrated (15) at the adapter and then tighten it to the rear cover (9). S4: Depending on the required pressure range, place the diaphragm between the high and low pressure chambers; S5: Open the solenoid valve (13), and the air compressor (12) fills the high-pressure chamber of the shock tube (14) with air. The filling speed is controlled by the air compressor (12). S6: When the pressure difference between high and low reaches the required pressure, the diaphragm ruptures, and a pressure step is generated between the high-pressure chamber and the low-pressure chamber, forming a shock wave. The pressure signal is sensed by the calibration sensor (15), and a corresponding electrical signal is generated and transmitted to the signal conditioner (16). The signal conditioner (16) outputs the conditioned signal to the data acquisition system (17) and records the data to the host computer (18).

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