A built-in spring safety valve for a valve clack sinking type tank car

Abstract

This utility model provides a recessed valve disc type built-in spring safety valve for tank trucks. The safety valve consists of a valve body, valve disc, valve stem, sealing gasket, spring, adjusting nut, and adjusting screw. The valve body has a deep cavity design, and the valve disc adopts a recessed structure with its edge having a built-in backflow groove that interacts with the valve body cavity to meet the discharge and reseating pressure requirements of the safety valve. The valve stem with a sealing disc forms a primary sealing structure with the sealing gasket and valve disc, while the valve stem neck forms a secondary sealing structure with the O-ring. A forced-closing bolt is installed at the upper end of the valve body. In case of slight leakage, the forced-closing bolt can be rotated to tighten the valve disc and prevent continuous leakage of the medium. The deep cavity of the valve body and the recessed valve disc design significantly reduce the height of the upper part of the safety valve, which is beneficial for increasing the tank truck volume and improving the overall height of the tank truck. The valve disc has a built-in backflow groove, eliminating the need for an adjusting ring and backflow disc structure. The set pressure of the safety valve is determined by adjusting the adjusting nut.

Description

Technical Field

[0001] This utility model relates to a built-in spring safety valve for tank cars with a sinking valve disc, belonging to the category of safety accessories and devices for mobile pressure vessels (such as railway tank cars and truck tank cars). Background Technology

[0002] A safety valve is a special valve that is normally closed under external force. When the pressure of the medium inside the equipment rises above a specified value, it releases the medium to the outside of the system to reduce the pressure. Once the pressure drops to the specified value, the safety valve automatically reseats. Many flammable and explosive liquefied gases and highly toxic chemicals are transported in tank trucks. A gas phase space exists at the top of the tank, and safety valves must be installed on the top of the tank truck to prevent overpressure during filling or transportation, which could lead to an explosion. Due to limitations imposed by factors such as safety valve height, tunnels, bridges, and tank truck volume, the overall height of tank trucks is restricted. Therefore, safety valves for tank trucks are usually built-in, meaning the safety valve spring is located at the bottom of the valve, and the valve body extends into the tank.

[0003] Even when using built-in safety valves, the upper part of these valves still protrudes significantly from the tank body. For example, in Chinese patents with authorization numbers CN203627958U and CN204239836U, the valve disc, sealing gasket, and other structures are located on the upper side of the safety valve flange. Furthermore, adjusting rings, backflushing discs, and protective covers are required to adjust the discharge and reseating pressures of the safety valve, resulting in a complex structure and difficult debugging. Therefore, it is necessary to develop a built-in safety valve for tank trucks that reduces valve height, is easy to operate, and meets national standard performance requirements. Utility Model Content

[0004] The purpose of this invention is to design a built-in spring safety valve for tank trucks with a sinking valve disc, in order to solve the problems mentioned in the background art.

[0005] To meet the performance requirements of safety valves in terms of setting, discharge, and reseating pressure, special design calculations are often required for the throat diameter, flow channel, relief chamber style and size, spring, etc.

[0006] To achieve the above objectives, this utility model provides the following technical solution: The safety valve consists of a valve body, valve disc, valve stem, sealing gasket, spring, adjusting nut, and adjusting nut. The valve body is internally designed as a deep cavity, and the valve disc adopts a recessed structure with a built-in backwash groove on its edge that interacts with the valve body cavity to meet the discharge and reseating pressure requirements of the safety valve. A sealing gasket is installed on the valve disc, and the valve stem, with its attached sealing disc, seals the gasket and valve disc together with fasteners to form a primary sealing structure. An O-ring is installed on the valve stem neck to form a secondary sealing structure. The upper end of the valve body is equipped with an adjusting nut, locking ring, forced closing bolt, and dust cover. When a slight leak occurs in the safety valve, the forced closing bolt can be rotated to tighten the valve disc and prevent continuous leakage of the medium. The lower end of the valve body is equipped with a spring, limit sleeve, spring seat, and adjusting nut.

[0007] This utility model is a built-in spring safety valve for tank trucks with a sinking valve disc. The deep cavity of the valve body and the sinking design of the valve disc significantly reduce the height of the upper part of the safety valve, which is conducive to increasing the tank truck volume and improving the overall height of the tank truck. The valve disc has a built-in backflow groove, eliminating the need for a special adjustment ring or backflow plate structure, and it is equipped with a safety valve forced closure bolt. Installation can be completed by adjusting the set pressure of the safety valve by adjusting the adjusting nut. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the overall structure of this safety valve.

[0009] Figure 2 This is a schematic diagram of the valve body structure of this safety valve.

[0010] Figure 3 This is a schematic diagram of the valve disc sealing assembly of this safety valve.

[0011] Figure 4 This is a schematic diagram of the adjusting valve of this safety valve.

[0012] In the diagram: 1. Nut; 2. Spring seat; 3. Limit sleeve; 4. Valve stem; 5. Valve body; 6. Valve disc; 7. Spring washer; 8. Set screw; 9. Locking nut; 10. Adjusting nut; 11. Locking ring; 12. Dust cover; 13. Forced closing bolt; 14. 20. Lead seal; 15. O-ring seal; 16. Sealing gasket; 17. Guide sleeve; 18. Spring; 19. Adjusting nut; 51. Pressure relief hole; 52. Guide arc; 53. Deep cavity; 54. Sealing surface; 55. Evaporation hole; 101. Exhaust hole; 102. Evaporation tank. Detailed Implementation

[0013] The technical solution of this patent will be further described in detail below with reference to specific embodiments.

[0014] See appendix Figure 1A type of built-in spring safety valve for tank trucks with a sinking valve disc. The safety valve consists of a valve body 5, a valve disc 6, a valve stem 4, a sealing gasket 16, a spring 18, an adjusting nut 10, and an adjusting nut 19.

[0015] See appendix Figure 2 The valve body 5 is internally designed as a deep cavity 53, forming a suitable cavity structure. After the safety valve opens, the discharged gas can generate a stable airflow and pressure above the valve disc 6 and the deep cavity 53, ensuring that the safety valve's discharge and reseating pressure performance meets relevant standards. The sealing surface 54 is conical, with a guide arc 52 on the lower side and pressure relief holes 51 on both sides. An evaporation hole 55 is present on the upper side of the valve body 5 flange. The guide sleeve 17 is installed to the bottom of the valve body 5 and partially welded to prevent it from falling off.

[0016] For further details, please refer to the appendix. Figure 3 The valve disc 6 features a built-in backflow groove on its edge, allowing for smooth airflow and providing lift when the safety valve is opened, enabling the valve disc 6 to fully open to a certain height. A sealing gasket 16 is installed, and an O-ring 15 is installed on the neck of the valve stem 4, inserted into the inner hole of the valve disc 6. A spring washer 7 is placed on top, and the locking nut 9 is tightened before installing two set screws 8. After overall tightening, the sealing disc attached to the valve stem 4, together with the sealing gasket 16 and the valve disc 6, forms a primary sealing structure, while the neck of the valve stem 4, together with the O-ring 15 and the inner hole of the valve disc 6, forms a secondary sealing structure, enhancing safety performance.

[0017] Furthermore, the valve stem 4, valve disc 6, and other components are installed into the valve body 5. A spring 18, a limiting sleeve 3, and a spring seat 2 are then placed sequentially at the lower end. An adjusting nut 19 is installed, its arc surface automatically aligning with the center of the conical surface of the spring seat 2. Tightening the adjusting nut 19 compresses the spring 18, creating a stable seal between the arc of the sealing gasket 16 and the conical sealing surface 54. The safety valve is placed on a valve inspection table, and its set pressure is adjusted by continuously adjusting the adjusting nut 19 until the set pressure of the safety valve is within acceptable limits. Then, a nut 1 is installed at the lower end of the adjusting nut 19, a hole is drilled, and a lead seal 20 is installed.

[0018] For further details, please refer to the appendix. Figure 4 The adjusting nut 10 is equipped with multiple vent holes 101 and an evaporation groove 102 at the bottom, with a pre-drilled threaded hole in the center. The adjusting nut 10 is installed on top of the valve body 5, and a locking ring 11 and a lead seal 14 are installed. A forced-closing bolt 13 is installed in the center of the adjusting nut 10. In case of minor leakage from the safety valve, the forced-closing bolt 13 can be rotated to tighten the valve disc 6, preventing continuous leakage of the medium. Then, a non-metallic dust cover 12 is installed into the groove at the top of the valve body 5.

[0019] After the safety valve opens, the valve disc 6, under the lift provided by the medium discharge, along with the valve stem 4, automatically moves upward along the inner hole of the guide sleeve 17. The spring 18 is compressed, creating a certain distance between the valve disc 6 and the sealing surface 54. The medium inside the tank enters the guide arc 52 through the pressure relief hole 51 on the side of the valve body 5, flows through the deep cavity 53 inside the valve disc 6 and the valve body 5, and then is discharged to the outside of the tank through multiple vent holes 101 on the adjusting nut 10. As the medium is discharged, the pressure of the medium inside the tank gradually decreases, and the airflow inside the deep cavity 53 gradually decreases. When the pressure of the medium inside the tank drops to the specified value, the valve disc 6, along with the valve stem 4, automatically descends back to its seat, and the sealing gasket 16 and the sealing surface 54 form a seal again, stopping the discharge of the medium.

[0020] Due to seasonal changes and temperature variations, condensation may occur at the bottom of the deep cavity 53 of the safety valve body 5. Since the dust cover 12 is connected to the valve body 5 through a groove, the condensation is not easily evaporated from the groove. The condensation can flow through the evaporation groove 102 on the adjusting nut 10 and through the evaporation hole 55 on the upper side of the valve body 5 until it is completely evaporated.

[0021] The embodiments of this patent have been described in detail above. However, this patent is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this patent.

Claims

1. A built-in spring safety valve for tank trucks with a sinking valve disc, characterized in that... It consists of a valve body, valve disc, valve stem, sealing gasket, spring, adjusting nut, and adjusting nut. The deep cavity of the valve body and the sinking design of the valve disc reduce the height of the upper part of the safety valve.

2. The built-in spring safety valve for tank trucks with a sinking valve disc as described in claim 1, characterized in that... The valve body (5) has a deep cavity (53) inside. After the safety valve is opened, the gas discharged can generate a stable airflow and pressure above the valve disc (6), inside the deep cavity (53) and in the multiple exhaust holes (101) of the adjusting valve (10).

3. The built-in spring safety valve for tank trucks with a sinking valve disc as described in claim 1, characterized in that... The edge of the valve disc (6) is a backflush groove. After installation, it sinks into the deep cavity (53) of the valve body (5). The valve stem (4) with the sealing disc and sealing gasket (16) and valve disc (6) form a primary sealing structure. The neck of the valve stem (4) and the O-ring seal (15) form a secondary sealing structure.

4. The built-in spring safety valve for tank trucks with a sinking valve disc as described in claim 1, characterized in that... A forced shut-off bolt (13) is installed in the center of the adjusting nut (10) on the upper part of the valve body (5). When the safety valve has a slight leakage, the valve disc (6) can be tightened by rotating the forced shut-off bolt (13).

5. The built-in spring safety valve for tank trucks with a sinking valve disc as described in claim 1, characterized in that... The valve body (5) is equipped with a non-metallic dust cover (12) at the top. The condensate that appears in the deep cavity (53) can be completely evaporated by the evaporation tank (102) on the adjusting screw (10) and the evaporation hole (55) on the upper side of the valve body (5).

6. The built-in spring safety valve for tank trucks with a sinking valve disc as described in claim 1, characterized in that... The bottom of the spring seat (2) has an adjusting nut (19) which can adjust the set pressure of the safety valve.

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