A quick pressure relief device for equalization test and application and preparation method

Abstract

The application relates to a quick pressure relief device for equal pressure test, application and a preparation method. The device comprises a container body, a head, a guide cylinder, a guide piston, a locking pin, a pin pulling shell and a stop block. A specified air pressure is introduced through the head air inlet, the pressure change in the container is monitored through a pressure sensor, high-pressure gas is introduced into the pin pulling shell when the test time reaches a specified value, the locking pin quickly retracts, the guide piston loses radial constraint, and the pressure difference between the inside and outside of the container rapidly pushes the guide piston out, thereby realizing quick pressure relief. The application is a mechanical structure and a pneumatic structure, the unlocking gas source is compressed air, high-cost electromagnetic locking pins or valves and a pyrotechnic pin puller are not needed, the work is reliable, and the cost is low.

Description

Technical Field

[0001] This invention belongs to the field of environmental testing and relates to a rapid pressure relief device for equalization testing, its application, and its preparation method. Background Technology

[0002] A certain test requires the product to be maintained at 0.6 MPa (absolute pressure) for 30 minutes, and then depressurized to atmospheric pressure at a rate of not less than 0.35 MPa / s. This test is the process of filling and venting the container. However, due to the requirement for a fast venting time, ordinary valves cannot meet the requirements, and there are special requirements for the venting area, pressure bearing capacity, and opening time of the valve.

[0003] The GJB150.2A standard specifies an explosion decompression test, which requires the pressure to decrease from 75.2 kPa to 18.8 kPa within 0.1 s. This test condition is also a rapid decompression process, but it is under negative pressure.

[0004] Chinese patent CN105521836A describes a low-pressure testing system that meets the requirements of the explosion decompression test specified in the GJB150.2A standard. It features two low-pressure chambers connected in series, employing a single vacuum system, various pipelines, and multiple valves to achieve different pressures in the two chambers. A burst valve is used in the middle to instantly depressurize one of the chambers through pressure balancing, thus meeting the test requirements. However, the system involves connecting two low-pressure containers, resulting in a complex structure, cumbersome installation, and high requirements for sealing.

[0005] Chinese patent CN104198208A describes a rapid decompression test device that uses a nested vacuum container method. Two sets of ventilation systems are used to extract the pressure of the two containers respectively. After the pressure in the two containers reaches the specified value, a pyrotechnic pin puller is used to quickly pull out the pin, the piston opens, and the air pressure is instantly balanced to achieve the test purpose.

[0006] Using ordinary ball valves or solenoid valves to open valves presents several problems:

[0007] (1) The diameter of the ordinary valve is insufficient, and the exhaust volume cannot meet the requirements;

[0008] (2) When the valve diameter meets the requirements, it needs to be opened instantly, which requires a high level of rapid response capability of the valve.

[0009] Using differential pressure to push out the piston is simple and feasible, but pin pulling requires a pin pulling device with a large pulling force. Electromagnetic pin pulling has a weak pin pulling force, while pin pulling for pyrotechnic devices is costly. Summary of the Invention

[0010] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a rapid pressure relief device for equalization tests, its application and preparation method.

[0011] The solution of the present invention is:

[0012] A rapid pressure relief device for equalization test includes a container body, a head, a guide cylinder, a guide piston, a locking pin, a pin release housing, and a stop block;

[0013] The container body and the end cap are sealed and fixed together. The top of the end cap has an air inlet, a central hole, and a sensor interface for installing a pressure sensor, with the central hole located at the center of the top of the end cap. A guide cylinder is fixed to the top of the end cap, and a guide piston is located inside the guide cylinder. A sealing ring is installed at the front end of the guide piston, and the guide piston is directly opposite the central hole at the top of the end cap. The side wall of the guide cylinder is machined with threaded holes, and the guide piston is machined with radial pin holes. During installation, the threaded holes on the side wall of the guide cylinder are aligned with the radial pin holes on the guide piston. A U-shaped groove is also machined on the side wall of the guide cylinder for venting.

[0014] The front end of the pin-pulling housing is fixedly connected to the guide cylinder. The pin-pulling housing is axially machined from front to back with a pin hole, an air storage hole, and a locking pin piston hole. The pin hole, air storage hole, and locking pin piston hole are interconnected and their diameters increase sequentially. The air storage hole is connected to the air inlet on the top of the pin-pulling housing. The locking pin is installed in the pin hole, and the locking pin piston is installed in the locking pin piston hole. The stop block is screwed to the rear end of the pin-pulling housing, and the center of the stop block is machined with an air hole that communicates with the locking pin piston hole. A sealing ring is provided between the locking pin and the pin-pulling housing.

[0015] Preferably, a groove is machined at the front end of the pin hole for installing the third O-ring.

[0016] Preferably, the locking pin consists of two cylindrical sections with grooves machined at the rear end, and is inserted into the pin hole after the fourth O-ring is installed.

[0017] Preferably, the U-shaped groove on the side wall of the guide cylinder is arranged at a 90° interval from the threaded hole on the side wall of the guide cylinder.

[0018] Preferably, a groove is machined on the flange surface of the container body, a first O-ring is installed in the groove, and the flange surface of the container body and the flange surface of the end cap are fixed together by bolts.

[0019] The application of a rapid pressure relief device for equalization tests includes:

[0020] Install a pressure sensor at the sensor interface;

[0021] Gas is introduced through the central air hole of the stop block, causing the locking pin to pass through the threaded hole on the side wall of the guide cylinder and insert into the radial pin hole on the guide piston;

[0022] Gas is introduced through the air inlet on the end cap, and pressure changes inside the container are monitored by a pressure sensor.

[0023] After the test time reaches the specified value, high-pressure gas is introduced into the air inlet above the pin housing. The locking pin retracts rapidly, the guide piston loses its radial constraint, and the pressure difference inside and outside the container pushes the guide piston upward quickly, achieving rapid pressure relief.

[0024] A method for preparing a rapid pressure relief device for equalization testing includes:

[0025] (1) Determine the inner diameter D and depth h of the container body based on the size of the test specimen;

[0026] (2) Determine the container wall thickness and end cap thickness based on the test pressure;

[0027] (3) Based on the test pressure P The number and grade of bolts n connecting the container body and the end cap are determined by the load-bearing area A of the container body, and the bolt strength. Must meet ;

[0028] (4) Determine the size of the O-ring between the container body and the end cap according to the connection dimensions of the two, and design the groove size according to the size of the O-ring;

[0029] (5) Design the thread size of the end cap inlet according to the vent valve interface, and design the sensor interface according to the pressure sensor size;

[0030] (6) Calculate the venting orifice diameter based on the container's inner diameter D and the venting time t. and effective venting area;

[0031] (7) Based on the vent diameter Determine the dimensions of the guide piston and the specifications of the O-ring installed at the front end of the guide piston;

[0032] (8) Based on the release pressure Guide piston area Calculate the force on the guide piston and locking pin diameter ,and , Shear modulus;

[0033] (9) Based on the retraction force of the locking pin , The coefficient of friction, the unlocking pressure ,according to Determine the force-bearing area of ​​the locking pin piston. and ventilation pressure ;

[0034] (10) According to the length of the locking pin Determine the internal cavity dimensions and length of the pin-pulling housing. Internal cavity diameter ;

[0035] (11) Determine the thickness and external structure of the pin release housing based on the unlocking pressure;

[0036] (12) Based on the outer diameter of the guide piston Determine the inner diameter of the guide cylinder ;

[0037] (13) Determine the external structure and installation method of the guide cylinder based on the mounting interface of the pull pin housing and the locking position of the guide piston.

[0038] Preferably, in step (13), .

[0039] Preferably, in step (6), the effective venting area satisfy:

[0040]

[0041]

[0042] This is the time for deflation. The constant of gas molecules, For container volume, For gas source temperature, For gas source pressure, This is the pressure after venting. It is a time constant. This is the critical gas pressure.

[0043] The advantages of this invention compared to the prior art are:

[0044] This invention features both mechanical and pneumatic structures. The unlocking air source is compressed air, eliminating the need for costly electromagnetic locking pins or valves, as well as pyrotechnic pin pullers. It is reliable and inexpensive. Attached Figure Description

[0045] Figure 1 This is a structural diagram of the rapid pressure relief device for the pressure equalization test;

[0046] Figure 2a This is a sectional view of the container.

[0047] Figure 2b This is a diagram of the head structure;

[0048] Figure 2c Here is a structural diagram of the guide cylinder;

[0049] Figure 2d Main view of the guide piston;

[0050] Figure 2e This is a structural diagram of the pin-pulling housing;

[0051] Figure 2f Main view of the locking pin;

[0052] Figure 2g This is a diagram of the stop block structure. Detailed Implementation

[0053] The invention will now be further described with reference to the accompanying drawings.

[0054] like Figure 1 , Figures 2a-2g As shown, the present invention provides a rapid pressure relief device for equalization testing, comprising a container body 11, a head 12, a guide cylinder 13, a guide piston 14, a locking pin 21, a pin-pulling housing 22, and a stop block 23.

[0055] Grooves are machined on the flange face of the container body 11, and the first O-ring 15 is installed in the groove. The flange face of the container body 11 and the flange face of the end cap 12 are fixed together by bolts 16. The top of the end cap 12 has an air inlet, a central hole, and the central hole is located at the center of the top of the end cap, as well as an air vent for exhaust and a threaded blind hole for fixing the guide tube. The guide tube flange face is machined with a through hole for connection with the end cap, and is connected to the end cap by bolts 17. A through hole is machined in the middle for installing the guide piston, and a threaded hole is machined on the side for installing the pull pin housing. A U-shaped groove is machined on the side wall perpendicular to the threaded hole for gas discharge. Specifically, the guide tube is fixed to the top of the end cap, the guide piston 14 is located in the guide tube, and a second O-ring 18 is installed at the front end of the guide piston 14, and the guide piston is directly opposite the center hole at the top of the end cap. The guide tube side wall is machined with a threaded hole, and the guide piston 14 is machined with a radial pin hole, and the threaded hole on the guide tube side wall is aligned with the radial pin hole on the guide piston during installation. A U-shaped groove is also machined on the guide tube side wall for venting, and the U-shaped groove on the guide tube side wall is arranged at a 90° interval from the threaded hole on the guide tube side wall.

[0056] The front end of the pin-pulling housing 22 is fixedly connected to the guide cylinder. The pin-pulling housing 22 has a pin hole, an air storage hole, and a guide piston hole machined axially from front to back. These holes are interconnected and their diameters increase sequentially. The air storage hole communicates with the air inlet at the top of the pin-pulling housing 22. A locking pin 21 is installed in the pin hole, and a locking pin piston is installed in the locking pin piston hole. A stop block 23 is screwed to the rear end of the pin-pulling housing 22. The center of the stop block 23 has an air hole communicating with the locking pin piston hole, used for venting air and for pushing the locking pin into the guide piston to lock it. A groove is machined at the front end of the pin hole for installing a third O-ring 24. The locking pin consists of two cylindrical sections with a groove machined at the rear end. After installing a fourth O-ring 25, it is inserted into the pin hole.

[0057] The application method of this invention is as follows:

[0058] The specified air pressure is introduced through the air inlet of the end cap 12, and the pressure change inside the container is monitored by the pressure sensor. After the test time reaches the specified value, high-pressure gas is introduced into the pin housing 22, the locking pin 21 retracts quickly, the piston 14 loses radial constraint, and the pressure difference inside and outside the container pushes the piston 14 out quickly, achieving rapid pressure relief.

[0059] The preparation steps of this invention are as follows:

[0060] (1) Determine the inner diameter D and depth h of the test container based on the size of the test specimen.

[0061] (2) Determine the wall thickness and head thickness of the vessel based on the test pressure and in accordance with GJB150 "Steel Pressure Vessels".

[0062] (3) Determine the number and grade of connecting bolts n based on the test pressure P and the force-bearing area A of the container body. The bolt strength must meet the requirements. 2 represents the safety margin.

[0063] (4) Determine the size of the first O-ring 15 based on the connection dimensions between the container body and the end cap, and design the groove dimensions based on the first O-ring. , The diameter of the end face of the first O-ring; The depth of the trench; Let be the clearance between the bore and shaft. Substituting the tolerance, the O-ring compression ratio can be calculated, which must be within the range of 10% to 30%. e represents the O-ring compression ratio.

[0064] (5) Design the thread size of the end cap air inlet according to the vent valve interface, and design the sensor interface according to the sensor size.

[0065] (6) Calculate using the gas cylinder venting formula. Determine the venting orifice diameter of the end cap based on the container diameter D and the venting time t. And the effective venting area, using the gas cylinder venting formula

[0066]

[0067] and the venting time constant, Calculate the venting time. - Gas molecular constant, air is 1.4, - Container volume -Effective venting area -Gas source temperature, -Gas source pressure, -Pressure after venting. .

[0068] (7) Based on the vent diameter Determine the size of the guide piston and the specifications of the O-ring installed at the front end of the guide piston.

[0069] (8) Based on the release pressure Guide piston area Calculate the force on the guide piston ,

[0070] Locking pin diameter , This is the shear modulus.

[0071] (9) Based on the retraction force of the locking pin , The coefficient of friction, the unlocking pressure ,according to Determine the force-bearing area of ​​the locking pin piston. and ventilation pressure .

[0072] (10) According to the length of the locking pin Determine the internal cavity dimensions of the pin-pulling housing, including its length. Its diameter .

[0073] (12) Based on the unlocking pressure The thickness of the shell and the external structure shall be determined in accordance with GJB150 "Steel Pressure Vessels".

[0074] (13) Based on the outer diameter of the piston Determine the inner diameter of the guide cylinder , .

[0075] (14) The external structure of the guide cylinder is determined according to the mounting interface of the pin housing and the locking position of the piston. Whether it is flange mounting or bolt mounting can be designed according to specific requirements.

[0076] The undisclosed technologies in this invention are common knowledge to those skilled in the art.

Claims

1. A rapid pressure relief device for equalization tests, characterized in that: It includes a container body (11), a head (12), a guide tube (13), a guide piston (14), a locking pin (21), a pull pin housing (22), and a stop block (23). The container body (11) and the end cap (12) are sealed and fixed together. The top of the end cap (12) has an air inlet, a central hole and a sensor interface for installing a pressure sensor, and the central hole is located at the center of the top of the end cap. The guide cylinder is fixed on the top of the end cap, and the guide piston (14) is located inside the guide cylinder. A sealing ring is installed at the front end of the guide piston (14), and the guide piston is directly opposite the central hole at the top of the end cap. The side wall of the guide cylinder is machined with a threaded hole, and the guide piston is machined with a radial pin hole. When installed, the threaded hole on the side wall of the guide cylinder is aligned with the radial pin hole on the guide piston. The side wall of the guide cylinder is also machined with a U-shaped groove for exhaust. The front end of the pin-pulling housing (22) is fixedly connected to the guide cylinder. The pin-pulling housing (22) is axially machined from front to back with a pin hole, an air storage hole and a locking pin piston hole. The pin hole, air storage hole and locking pin piston hole are interconnected and their diameters increase sequentially. The air storage hole is connected to the air inlet above the pin-pulling housing (22). The locking pin (21) is installed in the pin hole and the locking pin piston is installed in the locking pin piston hole. The stop block (23) is screwed to the rear end of the pin-pulling housing (22) and the center of the stop block (23) is machined with an air hole that is connected to the locking pin piston hole. A sealing ring is provided between the locking pin (21) and the pin-pulling housing (22). Grooves are machined on the flange face of the container body (11), and the first O-ring (15) is installed in the groove. The flange face of the container body (11) and the flange face of the end cap (12) are fixed together by bolts (16).

2. The rapid pressure relief device for equalization testing according to claim 1, characterized in that: A groove is machined at the front end of the pin hole for installing the third O-ring.

3. The rapid pressure relief device for equalization testing according to claim 1, characterized in that: The locking pin consists of two cylindrical sections with grooves machined at the rear end. After the fourth O-ring is installed, it is inserted into the pin hole.

4. The rapid pressure relief device for equalization testing according to claim 1, characterized in that: The U-shaped groove on the side wall of the guide cylinder is arranged at a 90° interval from the threaded hole on the side wall of the guide cylinder.

5. The application of the rapid pressure relief device for equalization testing according to any one of claims 1-4, characterized in that, include: Install a pressure sensor at the sensor interface; Gas is introduced through the central air hole of the stop block, causing the locking pin to pass through the threaded hole on the side wall of the guide cylinder and insert into the radial pin hole on the guide piston; Gas is introduced through the air inlet on the end cap, and pressure changes inside the container are monitored by a pressure sensor. After the test time reaches the specified value, high-pressure gas is introduced into the air inlet above the pin housing. The locking pin retracts rapidly, the guide piston loses its radial constraint, and the pressure difference inside and outside the container pushes the guide piston upward quickly, achieving rapid pressure relief.

6. A method for preparing a rapid pressure relief device for pressure equalization testing according to any one of claims 1-4, characterized in that, include: (1) Determine the inner diameter D and depth h of the container body based on the size of the test specimen; (2) Determine the container wall thickness and end cap thickness based on the test pressure; (3) Based on the test pressure P The number and grade of bolts n connecting the container body and the end cap are determined by the load-bearing area A of the container body, and the bolt strength. Must meet ; (4) Determine the size of the first O-ring between the container body and the end cap according to the connection dimensions of the two, and design the groove size according to the size of the first O-ring; (5) Design the thread size of the end cap inlet according to the vent valve interface, and design the sensor interface according to the pressure sensor size; (6) Calculate the central aperture based on the inner diameter D of the container and the venting time t. and effective venting area; (7) Based on the center aperture Determine the dimensions of the guide piston and the specifications of the sealing ring installed at the front end of the guide piston; (8) Based on the release pressure Guide piston area Calculate the force on the guide piston and locking pin diameter ,and , Shear modulus; (9) Based on the retraction force of the locking pin , The coefficient of friction, the unlocking pressure ,according to Determine the force-bearing area of ​​the locking pin piston. and ventilation pressure ; (10) According to the length of the locking pin Determine the internal cavity dimensions and length of the pin-pulling housing. Internal cavity diameter ; (11) Determine the thickness and external structure of the pin release housing based on the unlocking pressure; (12) Based on the outer diameter of the guide piston Determine the inner diameter of the guide cylinder ; (13) Determine the external structure and installation method of the guide cylinder based on the mounting interface of the pull pin housing and the locking position of the guide piston.

7. The method for preparing a rapid pressure relief device for equalization testing according to claim 6, characterized in that, In step (12), .

8. The method for preparing a rapid pressure relief device for equalization testing according to claim 6, characterized in that, In step (6), the effective venting area satisfy: This is the time for deflation. The constant of gas molecules, For container volume, For gas source temperature, For gas source pressure, This is the pressure after venting. It is a time constant. This is the critical gas pressure.

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