Ultralow-temperature butt welding end ball valve pressure test tool

Abstract

The utility model discloses an ultralow temperature butt welding end ball valve pressure test tool which comprises a left cover plate, a right cover plate and a stop block assembly, the stop block assembly is located between the left cover plate and the right cover plate, four studs penetrate through the left cover plate, the right cover plate and the four corners of the stop block assembly respectively, the two ends of each stud are connected with nuts in a threaded mode, two choke plugs are installed with the left cover plate and the stop block assembly respectively, and the two choke plugs are connected with the stop block assembly. Sealing grooves are formed in the inner end faces of the two choke plugs respectively, detection channels are arranged on the two choke plugs, one end opening of each detection channel is formed in the inner end face of the corresponding choke plug, the other end opening of each detection channel is formed in the side face of the corresponding choke plug, a steel pipe and a threaded adapter are arranged on the end openings, a threaded sleeve is arranged on the right cover plate in a penetrating mode, and a threaded rod is in threaded connection with the interior of the threaded sleeve. A wrench head is arranged at the outer end of the screw rod; and a winding pad and a red copper adjusting pad are sequentially adhered in the sealing groove from inside to outside. The pressure testing tool is good in sealing performance for the butt welding end ball valve, high in interchange universality and reliable in stability, and the performance is still good after multiple pressure tests.

Description

Technical Field

[0001] This utility model relates to the field of valve manufacturing, specifically to a pressure testing fixture for ultra-low temperature butt-welded ball valves. Background Technology

[0002] Cryogenic ball valves are crucial in liquefied natural gas (LNG) applications, as LNG is typically stored and transported at temperatures around -162°C. Cryogenic ball valves are specifically designed to operate stably in such extremely low temperatures, ensuring sealing and durability. A critical step in the production of cryogenic ball valves is performance testing (pressure testing). Traditional pressure testing equipment, when applied to test butt-welded ball valves, exhibits inconsistent performance, leading to leaks not caused by the valve itself, resulting in incorrect performance assessments and unnecessary losses. Furthermore, it lacks versatility, often requiring a separate pressure testing kit for each valve specification, resulting in high costs. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a low-temperature ball valve pressure testing fixture that can reliably seal both ends of the ball valve and has strong versatility.

[0004] To solve the above problems, the technical solution adopted by this utility model is as follows: a pressure testing fixture for a cryogenic butt-welded ball valve, characterized in that it includes: a left cover plate, a right cover plate, and a stop assembly. The left and right cover plates are arranged opposite each other, and the stop assembly is located between the left and right cover plates. Four parallel studs pass through the four corners of the left and right cover plates and the stop assembly, respectively. The left and right cover plates and the stop assembly can all move along the four studs to adjust their relative distance. A nut is threaded onto both ends of each of the four studs. The four nuts on the same side can block the outer side of the corresponding side cover plate to prevent the cover plate from detaching from the studs. Two end caps are arranged opposite each other and located between the stop assembly and the left cover plate. The two end caps are respectively installed with the left cover plate and the stop assembly. Sealing grooves for the butt-welded ball valve port to be inserted are respectively provided on the two inner end faces of the two end caps. After the butt-welded ball valve is placed between the two end caps, the two end caps are narrowed. The distance between the two end caps allows them to seal both ports of the butt-welded ball valve. Each end cap has a detection channel. One port of the detection channel is located on the inner end face of the end cap, allowing it to connect to one end of the butt-welded ball valve during testing. The other port is located on the side of the end cap, where a steel pipe and threaded adapter for connecting a pressure testing device are installed. A threaded sleeve passes through the right cover plate, with a blocking boss located between the right cover plate and the stop assembly at one end of the sleeve. The blocking boss abuts against the right cover plate. A tightening screw, when screwed in, holds the threaded sleeve in place. A threaded rod is threaded into the threaded sleeve, with a wrench at its outer end for driving rotation. When the rod is screwed in, its inner end pushes against the stop assembly, reducing the distance between the two end caps. A spiral wound gasket and a copper adjusting gasket are sequentially affixed from the inside out in the sealing groove.

[0005] Furthermore, in the aforementioned cryogenic butt-welded ball valve pressure testing fixture, the thread on the screw is a trapezoidal thread.

[0006] Furthermore, in the aforementioned cryogenic butt-welded ball valve pressure testing fixture, the left cover plate and the stop block assembly are both provided with mounting holes for mounting the end caps, and the outer end faces of the two end caps are provided with clips. The two end caps are installed by inserting the clips on them into the corresponding mounting holes.

[0007] Furthermore, in the aforementioned cryogenic ball valve pressure testing fixture, guide bosses are respectively provided on the inner end faces of the two plugs. When the plugs seal the port of the ball valve, the guide bosses can guide the port of the ball valve so that the port can be inserted into the sealing groove.

[0008] The advantages of this utility model are: the pressure testing fixture has good sealing performance for the ball valve at the welding end, strong interchangeability and versatility, reliable stability, and its performance remains good after multiple pressure tests. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the pressure testing fixture for the ultra-low temperature butt-welded ball valve described in this utility model. Detailed Implementation

[0010] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0011] like Figure 1 As shown, the cryogenic butt-welded ball valve pressure testing fixture includes: a left cover plate 1, a right cover plate 2, and a stop assembly 3. The left cover plate 1 and right cover plate 2 are arranged opposite each other, and the stop assembly 3 is located between the left cover plate 1 and right cover plate 2. Four parallel studs 4 pass through the four corners of the left cover plate 1, right cover plate 2, and stop assembly 3 respectively. The left cover plate 1, right cover plate 2, and stop assembly 3 can all move along the four studs 4 to adjust their relative distance. A nut 5 is threaded onto both ends of each of the four studs 4. The four nuts 5 located on the same side can block the outer side of the corresponding side cover plate to prevent the cover plate from contacting the studs. 4. The two end caps 6 are arranged opposite each other and located between the stop assembly 3 and the left cover plate 1. The two end caps 6 are respectively installed with the left cover plate 1 and the stop assembly 3. Sealing grooves 7 are provided on the two inner end faces of the two end caps 6 for the insertion of the butt-welding ball valve 8. After the butt-welding ball valve 8 is placed between the two end caps 6, the distance between the two end caps 6 can be reduced to seal the two ports of the butt-welding ball valve 8. Each end cap 6 is provided with a detection channel 9, one port of which is located on the inner end face of the end cap 6, allowing the detection channel 9 to contact the end cap 6 during detection. One end of the ball valve 8 is connected to the test channel 9, and the other port is located on the side of the end cap 6. A steel pipe 10 and a threaded adapter 11 for connecting the pressure testing equipment 20 are provided at this port. A threaded sleeve 12 passes through the right cover plate 2. A blocking boss 13 is located between the right cover plate 2 and the stop assembly 3 at one end of the threaded sleeve 12, abutting against the right cover plate 2. A tightening screw 15, which can be screwed in and press against the threaded sleeve 12, is provided on the right cover plate 2. A screw rod 14 is threaded into the threaded sleeve 12, and a drive screw rod 14 is provided at the outer end of the screw rod 14. After the rotating wrench 16 is screwed into the screw 14, the inner end of the screw 14 can push the stop assembly 3, so that the distance between the two end caps 6 can be reduced. In the sealing groove 7, a spiral wound gasket and a copper adjusting gasket are attached from the inside to the outside. The spiral wound gasket is made of austenitic stainless steel and flexible graphite, and the adjusting gasket is made of copper. When the port of the butt-welded ball valve is inserted into the sealing groove 7, it will first contact the copper adjusting gasket, and then press the spiral wound gasket to form a double gasket sealing structure, which can ensure the sealing of the pipeline under ultra-low temperature conditions, making the valve a sealed container for pressure testing, with good sealing performance.

[0012] In this embodiment, the thread on the screw 14 is a trapezoidal thread, which can withstand a larger load and is more durable.

[0013] Both the left cover plate 1 and the stop block assembly 3 are provided with mounting holes 17 for mounting the plugs 6. Each of the two plugs 6 has a locking head 18 on its outer end face. The two plugs 6 are installed by inserting the locking head 18 into the corresponding mounting hole 17.

[0014] Guide bosses 19 are provided on the inner end faces of the two end caps 6 respectively. When the end caps 6 seal the port of the ball valve 8 at the welding end, the guide bosses 19 can guide the port of the ball valve 8 at the welding end so that the port can be inserted into the sealing groove 7.

[0015] The distance between the left cover plate 1 and the right cover plate 2 can be adjusted to accommodate ball valves 8 of different specifications for butt welding ends.

[0016] During operation, the butt-welded ball valve 8 is placed between two blinds 6. By reducing the distance between the two blinds 6, the two blinds 6 can seal both ends of the butt-welded ball valve 8. The pressure testing equipment 20 is connected to the port of the butt-welded ball valve 8 through the steel pipe 10 and the test channel 9. Then, the pressure testing equipment 20 is used to test the butt-welded ball valve 8.

Claims

1. A pressure testing fixture for a cryogenic butt-welded ball valve, characterized in that: The system includes: a left cover plate, a right cover plate, and a stop assembly. The left and right cover plates are arranged opposite each other, and the stop assembly is located between them. Four parallel studs pass through the four corners of the left and right cover plates and the stop assembly. The left and right cover plates and the stop assembly can be moved along the four studs to adjust their relative distances. A nut is threaded onto both ends of each of the four studs. The four nuts on the same side can block the outer side of the corresponding side cover plate to prevent the cover plate from detaching from the studs. Two end caps are arranged opposite each other and located between the stop assembly and the left cover plate. The two end caps are installed with the left cover plate and the stop assembly, respectively. Sealing grooves for the insertion of the butt-welded ball valve port are provided on the two inner end faces of the two end caps. After the butt-welded ball valve is placed between the two end caps, reducing the distance between the two end caps allows the two end caps to seal the two ends of the butt-welded ball valve. The ports are sealed, and both end caps are equipped with detection channels. One port of the detection channel is located on the inner end face of the end cap, allowing it to connect with one end of the ball valve at the butt weld end during testing. The other port of the detection channel is located on the side of the end cap, and a steel pipe and threaded adapter for connecting the pressure testing equipment are provided at this port. A threaded sleeve is inserted through the right cover plate, and a blocking boss is provided at one end of the threaded sleeve between the right cover plate and the stop assembly. The blocking boss abuts against the right cover plate. A tightening screw is provided on the right cover plate, which can be screwed in to hold the threaded sleeve in place. A screw rod is threaded into the threaded sleeve, and a wrench is provided at the outer end of the screw rod to drive the screw rod to rotate. After the screw rod is screwed in, the inner end of the screw rod can push the stop assembly, thereby reducing the distance between the two end caps. A spiral wound gasket and a copper adjusting gasket are attached sequentially from the inside to the outside in the sealing groove.

2. The cryogenic butt-welded ball valve pressure testing fixture according to claim 1, characterized in that: The thread on the screw is a trapezoidal thread.

3. The cryogenic butt-welded ball valve pressure testing fixture according to claim 1 or 2, characterized in that: Both the left cover plate and the stop assembly are provided with mounting holes for mounting the end caps. Each end cap has a locking head on its outer end face. The two end caps are installed by inserting the locking heads into the corresponding mounting holes.

4. The cryogenic butt-welded ball valve pressure testing fixture according to claim 1 or 2, characterized in that: Guide bosses are provided on the inner end faces of the two end caps. When the end caps seal the port of the ball valve at the weld end, the guide bosses can guide the port of the ball valve at the weld end so that the port can be inserted into the sealing groove.

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