Quick pressure relief device for pressure equalizing test and application and preparation method of quick pressure relief device

Abstract

The invention relates to a quick pressure relief device for a pressure equalizing test and application and a preparation method thereof. The device comprises a container body, an end socket, a guide cylinder, a guide piston, a locking pin, a pin pulling shell and a stop block. Stipulated air pressure is introduced through an end socket air inlet, the pressure change condition in the container is monitored through a pressure sensor, after the test time reaches a stipulated required value, high-pressure air is introduced into the pin pulling shell, the locking pin rapidly retracts, the guide piston loses radial constraint, the guide piston is rapidly pushed out through the pressure difference between the interior and the exterior of the container, and rapid pressure relief is achieved. The device is of a mechanical structure and a pneumatic structure, an unlocking air source is compressed air, a high-cost electromagnetic lock pin or valve and an initiating explosive device pin puller are not needed for pin pulling, work is reliable, and cost is low.

Description

Technical Field

[0001] The invention belongs to the field of environmental testing and relates to a pressure equalization test quick pressure relief device and its application and preparation method. Background Art

[0002] A certain test requires that the product be kept at 0.6MPa (absolute pressure) for 30 minutes, and then the pressure is reduced to normal pressure at a rate of not less than 0.35MPa / s. This test is the filling and deflation process of the container, but because the deflation time is required to be fast, ordinary valves cannot meet the requirements, and there are special requirements for the deflation area, pressure bearing capacity and opening time of the valve.

[0003] The GJB150.2A standard stipulates the explosion decompression test, which requires the pressure to be reduced from 75.2kPa to 18.8kPa within 0.1s. The test condition is also a rapid pressure relief process, but it is a negative pressure.

[0004] Chinese patent CN105521836A is a low pressure test system that meets the requirements of the explosion decompression test specified in the GJB150.2A standard. Two low pressure chambers are connected in series, and a set of vacuum pumps, various pipes and multiple valves are used to achieve different pressures in the two pressure chambers. A burst valve is used in the middle to make one of the containers lose pressure instantly through pressure balance, thereby meeting the test requirements. The two low pressure containers are docked, the structure is complex, the installation is very troublesome, and the sealing requirements are high.

[0005] Chinese patent CN104198208A discloses a rapid decompression test device, which adopts a nested vacuum container method and uses two sets of exhaust systems 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] There are several problems with using ordinary ball valves or solenoid valves to open valves:

[0007] (1) The diameter of ordinary valves 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 places high demands on the valve's rapid response capability.

[0009] The method of using pressure difference to push out the piston is simple and feasible, but pulling out the pin requires a pin pulling device with a large pulling force, the electromagnetic pin pulling force is weak, and the pyrotechnic pin pulling is expensive. Summary of the invention

[0010] The technical problem solved by the present invention is to overcome the deficiencies of the prior art and to propose a pressure equalization test rapid pressure relief device, application and preparation method.

[0011] The solution of the present invention is:

[0012] A pressure equalization test quick pressure relief device, comprising a container body, a head, a guide cylinder, a guide piston, a locking pin, a pin removal housing, and a stopper;

[0013] The container body and the head are sealed and fixedly connected, and an air inlet, a center hole and a sensor interface for installing a pressure sensor are opened on the top of the head, and the center hole is located at the center of the top of the head; the guide cylinder is fixed on the top of the head, and the guide piston is located in the guide cylinder. A sealing ring is installed at the front end of the guide piston, and the guide piston is directly opposite to the center hole on the top of the head; a threaded hole is processed on the side wall of the guide cylinder, and a radial pin hole is processed on the guide piston, and when installing, the threaded hole on the side wall of the guide cylinder is aligned with the radial pin hole on the guide piston; a U-shaped groove is also processed on the side wall of the guide cylinder for exhaust;

[0014] The front end of the pin pulling shell is fixedly connected to the guide cylinder, and the pin rod hole, the air storage hole and the locking pin piston hole are processed in sequence from front to back in the axial direction of the pin pulling shell. The pin rod hole, the air storage hole and the locking pin piston hole are interconnected and their diameters increase in sequence, and the air storage hole is connected to the air inlet above the pin pulling shell; the locking pin is installed in the pin rod hole, the locking pin piston is installed in the locking pin piston hole, the stopper is screwed to the rear end of the pin pulling shell, and the air hole connected to the locking pin piston hole is processed in the center of the stopper; a sealing ring is arranged between the locking pin and the pin pulling shell.

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

[0016] Preferably, the locking pin is composed of two cylindrical sections, a groove is processed at the rear end, and the fourth O-ring is installed and then inserted into the pin rod hole.

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

[0018] Preferably, a groove is processed 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 head are fixedly connected by bolts.

[0019] An application of a pressure equalization test quick pressure relief device, comprising:

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

[0021] Let gas flow through the central air hole of the stopper so that the locking pin passes through the threaded hole on the side wall of the guide cylinder and is inserted into the radial pin hole on the guide piston;

[0022] The gas is introduced through the gas inlet on the head, and the pressure change in the container is monitored by the pressure sensor;

[0023] When the test time reaches the required value, high-pressure gas is introduced into the air inlet above the pin puller shell, the locking pin retracts quickly, the guide piston loses radial constraint, and the pressure difference inside and outside the container body pushes the guide piston upward quickly, achieving rapid pressure relief.

[0024] A method for preparing a pressure equalization test quick pressure relief device, comprising:

[0025] (1) Determine the inner diameter D and depth h of the container body according to the size of the test piece;

[0026] (2) Determine the wall thickness and head thickness of the vessel according to the test pressure;

[0027] (3) Determine the number n and grade of bolts connecting the vessel body and the head according to the test pressure P and the stress area A of the vessel body. The bolt strength T must satisfy T≥2PA / n;

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

[0029] (5) Design the thread size of the head air inlet according to the ventilation valve interface, and design the sensor interface according to the size of the pressure sensor;

[0030] (6) Calculate the venting hole diameter d based on the inner diameter D of the container and the venting time t 1 and effective venting area;

[0031] (7) According to the venting aperture d 1 Determine the size of the guide piston and the specifications of the O-ring installed at the front end of the guide piston;

[0032] (8) Calculate the force F on the guide piston based on the deflation pressure ΔP and the guide piston area S′. 1 and locking pin diameter d 2 ,and G is the shear modulus;

[0033] (9) According to the retraction force F of the locking pin 2 =μF 1 , μ is the friction coefficient, unlocking pressure F 3 >F 2 , according to F 3 =P B S A Determine the force area S of the locking pin piston A and ventilation pressure P B ;

[0034] (10) According to the length L of the locking pin 1 , determine the internal cavity size of the pin puller housing, the internal cavity length L 2 >L 1, internal cavity diameter

[0035] (11) Determine the thickness and external structure of the pull pin housing according to the unlocking pressure;

[0036] (12) According to the outer diameter of the guide piston d 4 Determine the inner diameter d of the guide cylinder 5 ;

[0037] (13) Determine the external structure and installation method of the guide cylinder according to the installation interface of the pin removal housing and the locking position of the guide piston.

[0038] Preferably, in step (13), d 4 =d 5 .

[0039] Preferably, in step (6), the effective degassing area S satisfies:

[0040]

[0041] t is the degassing time, k is the gas molecular constant, V is the container volume, T s is the gas source temperature, P A is the gas source pressure, P is the pressure after deflation, τ is the time constant, P * is the critical gas pressure.

[0042] The beneficial effects of the present invention compared with the prior art are:

[0043] The present invention has a mechanical structure and a pneumatic structure, and the unlocking air source is compressed air. It does not require a high-cost electromagnetic lock pin or valve and an explosive device pin puller to pull the pin, and has reliable operation and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the structural diagram of the quick pressure relief device for the pressure equalization test;

[0045] Figure 2a is a cross-sectional view of the container body;

[0046] Figure 2b This is the head structure diagram;

[0047] Figure 2c This is the structural diagram of the guide tube;

[0048] Figure 2d This is the front view of the guide piston;

[0049] Figure 2e It is the structural diagram of the pin-pulling housing;

[0050] Figure 2f It is the front view of the locking pin;

[0051] Figure 2g This is the block structure diagram. DETAILED DESCRIPTION

[0052] The present invention will be further described below in conjunction with the accompanying drawings.

[0053] like Figure 1 , Figure 2a-2g As shown, a pressure equalization test quick pressure relief device of the present invention includes a container body 11, a head 12, a guide cylinder 13, a guide piston 14, a locking pin 21, a pin removal housing 22, and a stopper 23.

[0054] A groove is processed on the flange surface of the container body 11, and a first O-ring 15 is installed in the groove. The flange surface of the container body 11 and the flange surface of the head 12 are fixedly connected by bolts 16; an air inlet and a center hole are opened on the top of the head 12, and the center hole is located at the center of the top of the head, as well as a vent hole for exhaust and a threaded blind hole for fixing the guide cylinder. A through hole is processed on the flange surface of the guide cylinder for connection with the head, and the guide cylinder is connected to the head by bolts. A through hole is processed in the middle for installing a guide piston, and a threaded hole is processed on the side for installing a pin extraction housing. A U-shaped groove is processed on the side wall perpendicular to the threaded hole for exhausting gas. Specifically, the guide cylinder is fixed to the top of the head, and the guide piston 14 is located in the guide cylinder. A second O-ring 18 is installed at the front end of the guide piston 14, and the guide piston is opposite to the center hole at the top of the head. A threaded hole is processed on the side wall of the guide cylinder, and a radial pin hole is processed on the guide piston 14. When installed, the threaded hole on the side wall of the guide cylinder is aligned with the radial pin hole on the guide piston. A U-shaped groove is also processed on the side wall of the guide cylinder for exhausting gas, and the U-shaped groove on the side wall of the guide cylinder is arranged at 90° from the threaded hole on the side wall of the guide cylinder.

[0055] The front end of the pin extraction housing 22 is fixedly connected to the guide cylinder. The pin rod hole, air storage hole and guide piston hole are processed in sequence from front to back in the pin extraction housing 22. The pin rod hole, air storage hole and guide piston hole are mutually connected and their diameters increase in sequence. The air storage hole is connected to the air inlet above the pin extraction housing 22. The locking pin 21 is installed in the pin rod hole, the locking pin piston is installed in the locking pin piston hole, the stopper 23 is screwed to the rear end of the pin extraction housing 22, and the center of the stopper 23 is processed with an air hole connected to the locking pin piston hole, which is used to exhaust air and push the locking pin into the guide piston to lock the guide piston. The front end of the pin rod hole is processed with a groove for installing the third O-ring. The locking pin is two cylindrical sections, and the rear end is processed with a groove. After the fourth O-ring is installed, it is installed in the pin rod hole.

[0056] The application method of the present invention is as follows:

[0057] The specified air pressure is introduced through the air inlet of the head 12, and the pressure change in the container is monitored by the pressure sensor. After the test time reaches the specified requirement value, high-pressure gas is introduced into the pin pulling shell 22, the locking pin 21 retracts quickly, the piston 14 loses radial constraint, and the pressure difference between the inside and outside of the container quickly pushes the piston 14 out to achieve rapid pressure relief.

[0058] The preparation steps of the present invention are as follows:

[0059] (1) Determine the inner diameter D and depth h of the test container according to the size of the test piece.

[0060] (2) Determine the vessel wall thickness and head thickness based on the test pressure and GJB150 "Steel Pressure Vessels".

[0061] (3) Determine the number n and grade of connecting bolts based on the test pressure P and the load-bearing area A of the container body. The bolt strength must meet T≥2PA / n, where 2 is the safety margin.

[0062] (4) Determine the size of the first O-ring 15 according to the connection size between the container body and the head, and design the groove size according to the first O-ring. 0 -(h′+c)] / d 0 , d 0 is the end face diameter of the first O-ring; h' is the groove depth; c is the hole-shaft clearance. Substituting the tolerance, the O-ring compression rate can be calculated, which must be within the range of 10% to 30%. e is the O-ring compression rate.

[0063] (5) Design the thread size of the head air inlet according to the ventilation valve interface, and design the sensor interface according to the sensor size.

[0064] (6) Calculate with reference to the formula for deflation of gas cylinders. Determine the deflation hole diameter d of the end cap according to the diameter D of the container and the deflation time t. 1 and effective deflation area, using the cylinder deflation formula

[0065]

[0066] and the deflation time constant, Calculate the deflation time, k-gas molecular constant, 1.4 for air, V-container volume, S-effective deflation area, T s - Gas source temperature, P A -gas source pressure, P-pressure after deflation. * =1.893×P.

[0067] (7) According to the venting aperture d 1 Determine the size of the pilot piston and the specifications of the O-ring installed on the front end of the pilot piston.

[0068] (8) Calculate the force F on the guide piston based on the deflation pressure ΔP and the guide piston area S′. 1 =ΔPS′, locking pin diameter G is the shear modulus.

[0069] (9) According to the retraction force F of the locking pin 2 =μF 1 , μ is the friction coefficient, unlocking pressure F 3 >F 2 , according to F 3 =P B S A Determine the force area S of the locking pin piston A and ventilation pressure P B .

[0070] (10) According to the length L of the locking pin 1 , determine the internal cavity size of the pin puller housing, its length L 2 >L 1 , its diameter

[0071] (12) According to the unlocking pressure P B The thickness and external structure of the pull pin shell shall be determined according to GJB150 "Steel Pressure Vessels" for installation.

[0072] (13) According to the outer diameter of the piston d 4 Determine the inner diameter d of the guide cylinder 5 , d 4 =d 5 .

[0073] (14) The external structure of the guide cylinder is determined according to the installation interface of the pin puller housing and the locking position of the piston. Whether it is flange mounted or screw mounted, it can be designed according to specific requirements.

[0074] The undisclosed technologies in the present invention are common knowledge to those skilled in the art.

Claims

1. A quick pressure relief device for pressure equalization test, characterized in that: It comprises a container body (11), a sealing head (12), a guide cylinder (13), a guide piston (14), a locking pin (21), a pin removal housing (22), and a stopper (23); The container body (11) and the end cap (12) are sealed and fixedly connected. The top of the end cap (12) is provided with an air inlet, a center hole and a sensor interface for installing a pressure sensor, and the center hole is located at the center position of the top of the end cap; the guide cylinder is fixed at the top of the end cap, the guide piston (14) is located in the guide cylinder, a sealing ring is installed at the front end of the guide piston (14), and the guide piston is directly opposite to the center hole at the top of the end cap; the side wall of the guide cylinder is processed with a threaded hole, the guide piston is processed with a radial pin hole, and 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 processed with a U-shaped groove for exhaust; The front end of the pin pulling housing (22) is fixedly connected to the guide cylinder, and the pin pulling housing (22) is processed with a pin rod hole, an air storage hole and a locking pin piston hole in sequence from front to back in the axial direction. The pin rod hole, the air storage hole and the locking pin piston hole are mutually connected and their diameters increase in sequence, and the air storage hole is communicated with the air inlet above the pin pulling housing (22); the locking pin (21) is installed in the pin rod hole, the locking pin piston is installed in the locking pin piston hole, the stopper (23) is screwed to the rear end of the pin pulling housing (22), and the center of the stopper (23) is processed with an air hole communicated with the locking pin piston hole; a sealing ring is arranged between the locking pin (21) and the pin pulling housing (22).

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

3. A pressure equalization test quick pressure relief device according to claim 1, characterized in that: The locking pin is composed of two cylindrical sections, with a groove machined at the rear end, which is installed into the pin rod hole after the fourth O-ring is installed.

4. A pressure equalization test quick pressure relief device according to claim 1, characterized in that: The U-shaped groove on the side wall of the guide cylinder is arranged at an interval of 90 degrees from the threaded hole on the side wall of the guide cylinder.

5. The quick pressure relief device for equalizing pressure test according to claim 1, characterized in that: A groove is machined on the flange surface of the container body (11), a first O-ring (15) is installed in the groove, and the flange surface of the container body (11) and the flange surface of the head (12) are fixedly connected by bolts (16).

6. Application of a pressure equalization test quick pressure relief device according to any one of claims 1 to 5, characterized in that: include: Install a pressure sensor on the sensor interface; Let gas flow through the central air hole of the stopper so that the locking pin passes through the threaded hole on the side wall of the guide cylinder and is inserted into the radial pin hole on the guide piston; The gas is introduced through the gas inlet on the head, and the pressure change in the container is monitored by the pressure sensor; When the test time reaches the specified requirement, high-pressure gas is introduced into the air inlet above the pin puller shell, the locking pin retracts quickly, the guide piston loses radial constraint, and the pressure difference inside and outside the container body pushes the guide piston upward quickly to achieve rapid pressure relief.

7. A method for preparing a pressure equalization test rapid pressure relief device according to any one of claims 1 to 5, characterized in that: include: (1) Determine the inner diameter D and depth h of the container body according to the size of the test piece; (2) Determine the wall thickness and head thickness of the vessel according to the test pressure; (3) Determine the number n and grade of bolts connecting the vessel body and the head according to the test pressure P and the stress area A of the vessel body. The bolt strength T must satisfy T≥2PA / n; (4) Determine the size of the O-ring between the container body and the head according to the connection size between the two, and design the groove size according to the size of the O-ring; (5) Design the thread size of the head air inlet according to the ventilation valve interface, and design the sensor interface according to the size of the pressure sensor; (6) Calculate the venting hole diameter d1 and the effective venting area based on the inner diameter D of the container and the venting time t; (7) Determine the size of the guide piston and the specifications of the O-ring installed at the front end of the guide piston based on the venting hole diameter d1; (8) According to the deflation pressure ΔP and the guide piston area S′, calculate the guide piston force F1 and the locking pin diameter d2, and G is the shear modulus; (9) According to the retraction force of the locking pin F2 = μF1, μ is the friction coefficient, the unlocking pressure F3>F2, according to F3 = P B S A Determine the force area S of the locking pin piston A and ventilation pressure P B ; (10) According to the length L1 of the locking pin, determine the internal cavity size of the pin puller housing. The internal cavity length L2>L1, and the internal cavity diameter (11) Determine the thickness and external structure of the pull pin housing according to the unlocking pressure; (12) Determine the inner diameter d5 of the guide cylinder according to the outer diameter d4 of the guide piston; (13) Determine the external structure and installation method of the guide cylinder according to the installation interface of the pin removal housing and the locking position of the guide piston.

8. The method for preparing a pressure equalization test rapid pressure relief device according to claim 7, characterized in that: In the step (13), d4=d5.

9. The method for preparing a pressure equalization test rapid pressure relief device according to claim 7, characterized in that: In step (6), the effective degassing area S satisfies: t is the degassing time, k is the gas molecular constant, V is the container volume, T s is the gas source temperature, P A is the gas source pressure, P is the pressure after deflation, τ is the time constant, P * is the critical gas pressure.

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