High-pressure safety valve checking device

Abstract

The utility model relates to a high-pressure safety valve checking device, which is characterized in that a pressing disc is a disc-shaped combined body with a large diameter and a small diameter, the shaft part of the large-diameter disc body is provided with a through hole for checking gas to pass through, and the periphery of the large-diameter disc body near the edge is provided with at least more than three screw holes which correspond to a safety valve inlet flange and are used for mounting screws; a sealing ring groove is formed in a circle of the upper surface close to the shaft part; the screw rod is in threaded fit connection with the screw hole and is fastened on the safety valve inlet flange through a nut; the shaft part of the small-diameter disc body is provided with a counter bore matched with the excircle surface of the air inlet where the checking table is located; the pull claw downwards tensions the safety valve on the upper face of the safety valve inlet flange, and the air inlet end face where the checking table is located is in sealed fit with the counter bore of the small-diameter disc body through the second sealing ring. The pre-assembled structure of the safety valve and the pressing disc improves the sealing effect, reduces the leakage phenomenon in a high-pressure test environment, and reduces the frequency of damage of the sealing ring due to fatigue.

Description

Technical Field

[0001] The invention belongs to the technical field of safety valve calibration, and in particular relates to a high-pressure safety valve calibration device. Background Art

[0002] Since the safety valve 1, a special component in chemical enterprises, must be calibrated regularly, the calibration of the safety valve 1 is a basic task in the management of special components in the chemical industry. Figure 1 As shown, when the safety valve 1 is calibrated, the safety valve 1 is placed above the calibration table 6, and the inlet flange end of the safety valve 1 is installed corresponding to the air inlet end of the calibration table 6 through the pressure plate 2, and then three claws 5 are used to press downward from the upper part of the inlet flange of the safety valve 1, so that the safety valve 1 is reliably fixed, wherein the driving movement of the claws 5 is usually completed by a hydraulic / or pneumatic device; the pressure plate 2 is a large and a small cylindrical body, wherein the shaft portion of the small cylindrical body part is provided with a countersunk hole matching the air inlet of the calibration table 6, wherein the shaft portion of the large cylindrical body part is provided with a calibration gas hole; a number of annular grooves are provided on the contact surface between the pressure plate 2 and the surface of the inlet flange end where the safety valve 1 is located, and a first O-type sealing ring 3 is installed in the annular groove, and the countersunk hole where the pressure plate 2 is located and the contact surface of the air inlet end surface where the calibration table 6 is located are sealed with a second O-type sealing ring 4, and the material of the first sealing ring 3 and the second sealing ring 4 is rubber. During the calibration process, the air pump is turned on to press the test gas (usually an inert gas such as air or nitrogen) into the cavity of the safety valve 1 through the air inlet where the calibration table 6 is located and the test gas hole where the pressure plate 2 is located, and from the gas channel of the inlet flange where the safety valve 1 is located. When the pressure in the sealed cavity formed by the valve disc and the valve seat in the safety valve 1 exceeds the force exerted on the valve disc by the loading mechanism, the valve disc is pushed open, and the test gas is discharged. The pressure gauge on the calibration console can display the trip pressure in real time. At this time, after the pressure in the cavity of the safety valve 1 drops, since the force exerted on the valve disc by the loading mechanism is greater than the force exerted on it by the test gas, the valve disc will press the valve seat, and the safety valve 1 will be closed. By adjusting the tightening force of the loading mechanism of the safety valve 1, the trip pressure (also called the set pressure) of the safety valve 1 can be adjusted, thereby realizing the calibration of the safety valve.

[0003] However, during the calibration of the safety valve 1, each time the pressure of the test gas filled into the safety valve 1 rises to a high pressure range, there is sometimes a phenomenon of gas leakage from the sealing ring at the pressure plate, which affects the smooth progress of the calibration. At this time, the calibration personnel need to increase the work done by the hydraulic / or pneumatic device to further increase the downward pulling force of the claw 5 to achieve the purpose of clamping the safety valve 1; but the above method often causes premature fatigue and damage to the rubber O-type first sealing ring 3 and the second sealing ring 4, and then the replacement frequency is too fast, which not only wastes time but also increases costs. Summary of the Invention

[0004] In response to the problems mentioned in the background technology, the present invention provides a high-pressure safety valve verification device, including a pressure plate 2, which is a coaxial disc-shaped assembly of two discs, one large and one small in diameter, with the upper portion being a disc body with a large diameter and the lower portion being a disc body with a small diameter; the shaft portion of the disc body with a large diameter is provided with a through hole for testing the passage of gas, and a circle of at least three screw holes 22 for mounting a screw rod 7 corresponding to the inlet flange of the safety valve are provided on the near edge thereof, and a sealing ring groove 21 is provided on the upper surface thereof near the shaft portion; the screw rod 7 is threadedly connected to the screw hole 22 and is fastened to the safety valve 1 by a nut 8 Above the inlet flange; the shaft of the small-diameter disc body is provided with a countersunk hole for matching the outer cylindrical surface of the air inlet where the calibration bench 6 is located; the diameter of the through hole of the air inlet where the calibration bench 6 is located is the same as the diameter of the through hole where the large-diameter disc body is located; the groove shape of the sealing ring groove 21 is adapted to the outer shape of the first sealing ring 3; the pressure plate 2 and the inlet flange end where the safety valve 1 is located are detachably connected by a screw 7; the calibration bench 6 includes a pull claw 5, which pulls the safety valve 1 downward on the top of the inlet flange of the safety valve 1, and the air inlet end face where the calibration bench 6 is located forms a sealed fit with the countersunk hole of the small-diameter disc body through the second sealing ring 4.

[0005] Preferably, the first sealing ring 3 is a metal octagonal pad or a metal lens pad.

[0006] Furthermore, the large-diameter disc body where the pressure plate 2 is located is detachably connected to the inlet flange of the safety valve 1 through a screw 7, and the first sealing ring 3 is installed in the sealing ring groove 21; the screw 7 is threadedly connected to the screw hole 22 and is fastened to the top of the inlet flange of the safety valve 1 through a nut 8.

[0007] Furthermore, the sealing ring groove 21 adapted to the metal octagonal gasket is annular, and the sealing ring groove 21 is located in the middle of the screw hole 22 where the large-diameter disc body is located and the through hole.

[0008] Furthermore, the sealing ring groove 21 adapted to the metal lens pad is a circular sink, and the edge of the circular sink is processed into a chamfer.

[0009] Preferably, the pressing plate 2 is made of metal.

[0010] Optionally, the screw hole 22 may be a through hole, and the screw rod 7 is fixed below the pressure plate 2 via another nut.

[0011] Preferably, the shaft portion of the small-diameter disc body is provided with a countersunk hole for matching with the outer circular surface of the air inlet where the calibration platform 6 is located, and the two are clearance-fitted.

[0012] Beneficial effects: The high-pressure safety valve calibration device solves the problem that the seal between the pressure plate and the safety valve inlet flange is unreliable during the calibration of high-pressure safety valves, and leakage often occurs, resulting in the inability to calibrate the high-pressure safety valve normally. A through hole is processed in the middle of the pressure plate, and a sealing ring is installed between the pressure plate and the safety valve. The pressure plate and the safety valve inlet flange are connected and tightened with bolts and nuts. A sealing system is formed between the pressure plate and the calibration table through another sealing ring. After the pressure plate and the safety valve inlet flange are reliably connected, it is placed on the calibration table and tightened by the claw to fix it on the calibration table for safety valve calibration. The pre-assembled structure of the safety valve and the pressure plate improves the sealing effect between the two and reduces the possibility of leakage of the test gas at this location under a high-pressure test environment. Based on the bolt and nut connection structure between the pressure plate and the safety valve inlet flange, the force value of the sealing ring tends to be stable, thereby avoiding the frequency of fatigue and damage to the sealing ring caused by increasing the work done by the hydraulic / or pneumatic device to further increase the downward pulling force of the claw when gas leakage occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 This is a schematic diagram of the connection structure of the safety valve during calibration as referred to in the background art;

[0015] Figure 2 This is a schematic diagram of the connection structure of the safety valve during calibration of the utility model;

[0016] Figure 3 This is a structural diagram of the pressure plate, and the sealing ring is a metal octagonal pad;

[0017] Figure 4 for Figure 3 AA section view;

[0018] Figure 5 This is a schematic diagram of the structure of the pressure plate, and the sealing ring is a metal lens pad;

[0019] Figure 6 for Figure 5 BB cross-sectional view;

[0020] In the figure: safety valve 1, pressure plate 2, sealing ring groove 21, screw hole 22, first sealing ring 3, second sealing ring 4, pulling claw 5, calibration table 6, screw 7, nut 8. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] In one embodiment of the present invention, please refer to the attached Figure 2 As shown, Example 1:

[0023] A high-pressure safety valve calibration device includes a pressure plate 2, which is a coaxial disc-shaped assembly of two discs, one larger and one smaller in diameter. The upper portion of the pressure plate is a disc with a larger diameter, and the lower portion is a disc with a smaller diameter. The shaft of the disc with a larger diameter is provided with a through hole for testing the passage of gas. At least three screw holes 22 for mounting a screw rod 7 are provided around its edge and correspond to the inlet flange of the safety valve. A sealing ring groove 21 is provided on its upper surface near its shaft. The screw rod 7 is threadedly connected to the screw hole 22 and is fastened to the inlet flange of the safety valve 1 by a nut 8. The small The shaft of the large-diameter disc body is provided with a countersunk hole for matching the outer circular surface of the air inlet where the calibration platform 6 is located; the diameter of the through hole of the air inlet where the calibration platform 6 is located is the same as the diameter of the through hole where the large-diameter disc body is located; the groove shape of the sealing ring groove 21 is adapted to the outer shape of the first sealing ring 3; the pressure plate 2 and the inlet flange end where the safety valve 1 is located are detachably connected by a screw 7; the calibration platform 6 includes a pulling claw 5, which pulls the safety valve 1 downward on the inlet flange of the safety valve 1, and the air inlet end face where the calibration platform 6 is located forms a sealed fit with the countersunk hole of the small-diameter disc body through the second sealing ring 4.

[0024] Specifically, the first sealing ring 3 is a metal octagonal gasket or a metal lens gasket. Optionally, the sealing ring groove 21 is predetermined based on the sealing form of the inlet flange of the safety valve 1. The safety valve 1 used by the inventor's unit is a high-pressure type, and the first sealing ring 3 suitable for it has a lens surface, a concave-convex surface, a tongue-and-groove surface, or a ring connection surface.

[0025] The pressure plate used in the safety valve calibration described above has a large-diameter circular disc body, housing the pressure plate 2, which is removably connected to the inlet flange of the safety valve 1 via a screw 7. A first sealing ring 3 is installed within the sealing ring groove 21. The screw 7 is threadedly engaged with the threaded hole 22 and fastened to the inlet flange of the safety valve 1 via a nut 8. This connection structure ensures a secure connection between the pressure plate 2 and the inlet flange of the safety valve 1, securely securing the first sealing ring 3. The preload applied to the pressure plate 2 is provided by the screw 7 and nut 8, and this preload is set according to the sealing requirements and is not affected by increasing the tension of the claw 5, thereby ensuring the preload parameter conditions for the first sealing ring 3. During the inspection, after the safety valve 1 and the pressure plate 2 are pre-assembled, they are hoisted as a whole onto the calibration table 6, and the hydraulic or pneumatic equipment is driven to make the claw 5 pull downward to tighten the top of the inlet flange of the safety valve 1. The contact surface between the countersunk end face of the small-diameter circular disc body of the pressure plate 2 and the air inlet end face of the calibration table 6 is sealed by the second sealing ring 4, thereby forming a sealed fit to carry out the calibration test of the safety valve 1.

[0026] Specifically, in one embodiment of the present invention, please refer to the attached Figure 3 and 4 As shown, in embodiment 2, the sealing ring groove 21 adapted to the metal octagonal gasket is annular, and the sealing ring groove 21 is located in the middle position between the screw hole 22 where the large diameter disc body is located and the through hole.

[0027] Specifically, in one embodiment of the present invention, please refer to the attached Figure 5 and 6 As shown in Example 3, the sealing ring groove 21 adapted to the metal lens pad is a circular sink, and the edge of the circular sink is processed into a chamfer to remove the sharp corners of the edge.

[0028] Preferably, the pressing plate 2 is made of metal.

[0029] Optionally, the screw hole 22 may be a through hole, and the screw rod 7 is fixed below the pressure plate 2 via another nut; this is suitable for situations where the pulling claw 5 is relatively long.

[0030] Preferably, the shaft portion of the small-diameter disc body is provided with a countersunk hole for matching with the outer circular surface of the air inlet where the calibration platform 6 is located, and the two are clearance-fitted.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-pressure safety valve calibration device, characterized in that: The invention comprises a pressure plate (2), wherein the pressure plate (2) is a disc-shaped assembly of two coaxial discs with a larger diameter and a smaller diameter, wherein the upper portion is a disc body with a larger diameter and the lower portion is a disc body with a smaller diameter; the axis of the disc body with a larger diameter is provided with a through hole for checking the passage of gas, and at least three screw holes (22) for mounting a screw rod (7) are provided on a circle near the edge thereof and correspond to the inlet flange of the safety valve, and a sealing ring groove (21) is provided on a circle near the axis thereof; the screw rod (7) is threadedly connected to the screw hole (22) and is fastened to the inlet flange of the safety valve (1) by a nut (8). Above; the shaft portion of the small-diameter disc body is provided with a countersunk hole for matching the outer cylindrical surface of the air inlet where the calibration table (6) is located; the diameter of the through hole of the air inlet where the calibration table (6) is located is the same as the diameter of the through hole where the large-diameter disc body is located; the groove shape of the sealing ring groove (21) is adapted to the outer shape of the first sealing ring (3); the calibration table (6) includes a pulling claw (5), and the pulling claw (5) tightens the safety valve (1) downward on the inlet flange of the safety valve (1), and the air inlet end face of the calibration table (6) forms a sealed fit with the countersunk hole of the small-diameter disc body through the second sealing ring (4).

2. A high-pressure safety valve calibration device according to claim 1, characterized in that: The large-diameter disc body where the pressure plate (2) is located is detachably connected to the inlet flange of the safety valve (1) via a screw (7), and a first sealing ring (3) is installed in the sealing ring groove (21).

3. A high-pressure safety valve calibration device according to claim 2, characterized in that: The first sealing ring (3) is a metal octagonal pad or a metal lens pad.

4. A high-pressure safety valve calibration device according to claim 3, characterized in that: The sealing ring groove (21) adapted to the metal octagonal gasket is annular, and the sealing ring groove (21) is located in the middle of the screw hole (22) where the large-diameter disc body is located and the through hole.

5. A high-pressure safety valve calibration device according to claim 3, characterized in that: The sealing ring groove (21) adapted to the metal lens pad is a circular sink, and the edge of the circular sink is processed into a chamfer.

6. A high-pressure safety valve calibration device according to any one of claims 1 to 5, characterized in that: The pressing plate (2) is made of metal.

7. A high-pressure safety valve calibration device according to claim 6, characterized in that: The screw hole (22) is a through hole, and the screw rod (7) is fixed below the pressure plate (2) through another nut.

8. A high-pressure safety valve calibration device according to claim 6, characterized in that: The shaft portion of the small-diameter disc body is provided with a countersunk hole for matching the outer circular surface of the air inlet where the calibration table (6) is located, and the two are clearance-fitted.

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