Low-temperature ball valve pressure and sealing test tool

Abstract

The utility model discloses a low-temperature ball valve pressure and sealing test tool. The tool comprises a first tool; the second tool assembly comprises two separable semi-ring bodies; wherein the first tool assembly is a disc-shaped piece, and the second tool assembly can be spliced into the disc-shaped piece; the first tool assembly and the second tool assembly can be clamped on the front side and the rear side of a valve flange to be tested and are connected on the outer side of the outer edge of the valve flange. Through a combined structure of the split type semi-ring body and the disc-shaped tool, multi-flange standard adaptation of valves with the same caliber is achieved. The first tool and the detachable second tool assembly are connected through the outer sides to form the clamping type tool, test plates do not need to be independently manufactured according to different flange outer diameters and hole pitches, the number of the special test plates is greatly reduced, and the production cost and the storage pressure are remarkably reduced.

Description

Technical Field

[0001] This utility model relates to the field of valve body testing devices, and in particular to a pressure and sealing testing tool for cryogenic ball valves. Background Technology

[0002] Cryogenic ball valves are widely used in media transportation pipelines ranging from -100℃ to -196℃, and they must undergo pressure and sealing tests under simulated operating conditions before leaving the factory. Currently, the valve testing tools commonly used in the industry have significant shortcomings: although conventional test benches are equipped with dual-sided hydraulic devices, they are only suitable for ambient temperature environments and cannot meet the requirements of cryogenic conditions. For example, the "Valve Testing Bench with Positioning Fixture" disclosed in Chinese patent literature, publication number "CN211121959U", includes a tabletop and a U-shaped frame fixedly connected to the tabletop. A lower positioning sealing disc is embedded at the top of the U-shaped frame, and a lower guide pipe is sealed through the lower positioning sealing disc. A test pipe is threadedly connected to the bottom end of the lower guide pipe. A horizontal plate is fixedly connected to the upper side of the tabletop via a vertical plate. By limiting the valve between the fixed lower positioning sealing disc and the downward-pressing upper positioning sealing disc, the valve is limited by pressing down on the upper and lower flange openings, eliminating the need for bolt and nut connections.

[0003] The current problem is that, due to differences in flange outer diameter, bolt hole number, and bore diameter between valves of the same diameter under different pressure ratings (e.g., CL150 / CL300) and flange standards (ASME / GB, etc.), companies have to manufacture dedicated test plates for each specification. For example, with a DN100 valve, if it involves three pressure ratings and two flange standards, six completely different test plates are required. Figure 1 The tooling device shown includes a special flange test plate 1.0 with the outer end face of the valve flange 100. The special flange test plate 1.0 has a mounting hole corresponding to the connection hole of the valve flange 100 of this model. A bolt assembly 2.0 that penetrates the special flange test plate 1.0 and the valve flange 100 is installed in the mounting hole. The bolt assembly 2.0 includes nuts 2.1 respectively located on the outer end face of the special flange test plate 1.0 and the back end face of the valve flange 100.

[0004] This "one valve, one plate" model has led to a surge in the number of test plates, consuming large amounts of steel and incurring high processing costs, while also requiring dedicated storage and management space. In actual production, it has also been found that frequent test plate replacements result in equipment downtime exceeding 30%, severely impacting testing efficiency.

[0005] Other existing improvements also have a general scheme through adjustable structure, but the complex slider, screw rod and other adjusting components are prone to deformation at low temperature, which in turn causes new sealing failure problems. Therefore, how to build a test device that can adapt to multiple specifications and withstand extreme temperature tests has become a technical bottleneck that the industry urgently needs to break through. Practical new type content

[0006] In view of the problem that the low-temperature ball valve test tool needs to be designed according to different types of valves, resulting in high test cost, the utility model provides a kind of low-temperature ball valve pressure and sealing test tool, using the universal flange test plate in low-temperature environment, to cover a variety of same caliber different pressure and flange standard low-temperature ball valve, greatly save cost and time.

[0007] To achieve the above purpose, the utility model adopts the following technical scheme:

[0008] A kind of low-temperature ball valve pressure and sealing test tool, comprising: first tooling;Second tooling assembly, comprising two separable half rings;Wherein, the first tooling is disc type piece, and second tooling assembly can be spliced into disc type piece;Wherein, the first tooling and second tooling assembly can be clamped on the front and back two sides of the valve flange to be tested, and connected outside the outer edge of the valve flange.

[0009] Further, the first tooling is provided with a first axial connecting hole group along the outer edge, the second tooling assembly includes a second axial connecting hole group corresponding to the first axial connecting hole group, and a connecting assembly is arranged between the first axial connecting hole group and the second axial connecting hole group, and the connecting assembly is installed outside the outer edge of the valve flange to be tested.

[0010] Further, the first axial connecting hole group includes a plurality of connecting holes one arranged uniformly along the circumference, and the second axial connecting hole group includes a plurality of connecting holes two corresponding to the connecting holes one, and the connecting piece is a bolt installed in the corresponding connecting holes one and connecting holes two.

[0011] Further, the connecting assembly includes a bolt penetrating the connecting holes one and the connecting holes two corresponding to the connecting holes one, and further includes two nuts respectively arranged at both ends of the bolt, and the two nuts are respectively abutted with the outer end surface of the first tooling and the outer end surface of the second tooling assembly.

[0012] Further, the first tooling is provided with a first ear hole on both sides in the radial direction, the second tooling assembly includes a second ear hole corresponding to the first ear hole, the second ear hole is formed by splicing the half ear holes arranged on the two half rings, and a connecting assembly is arranged between the first ear hole and the second ear hole.

[0013] Further, the two half ear holes are provided with split threads; when the two half ring bodies are combined, the split threads on both sides are combined to form a complete internal threaded hole; the orifice of the internal threaded hole is formed with a complete boss, and the nut end face of the connecting assembly is provided with a ring groove corresponding to the boss, and the split surface is sealed by nesting the ring groove and the complete boss when tightened.

[0014] Further, the first tool is provided with a compensating gasket layer on the inner end face, which expands and compensates the gap between the first tool and the valve flange when the working temperature drops; the compensating gasket layer comprises at least one radial distribution radiation groove.

[0015] Further, the first tool and the second tool assembly are provided with through holes at the center, and a guide pipe can be arranged in the through hole.

[0016] Therefore, the utility model has the following beneficial effects:

[0017] Through the split half ring body and the disc type tool assembly structure, the same caliber valve multi-flange standard is adapted. The first tool and the detachable second tool assembly are connected on the outside to form a clamping tool, which does not need to manufacture test plates separately for different flange outer diameters and hole distances, greatly reduces the number of special test plates, and significantly reduces the production cost and storage pressure.

[0018] The axial connection hole group and the split thread structure make the bolt fastening force uniformly act on the split surface, and the stable pre-tightening force can be maintained at-196 DEG C low temperature, solving the problems of bolt loosening and sealing failure of the traditional test tool caused by material shrinkage.

[0019] The gasket layer expands to fill the shrinkage gap between the tool and the flange under low temperature working condition, and the radiation groove releases thermal stress, so that the sealing surface continuously and effectively contacts when the temperature changes greatly, and the test pressure stability is effectively improved.

[0020] The modular connecting assembly realizes quick disassembly, assembly and conversion, the through hole guide pipe structure makes the test system compatible with valves of different pressure grades, and the utilization rate of the test equipment is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a structural schematic view of the traditional tool in the background art.

[0022] Figure 2 It is a structural schematic view of the utility model.

[0023] Figure 3 It is a front view of the first tool in embodiment 1.

[0024] Figure 4 It is an assembly view of the second tool assembly in embodiment 1.

[0025] Figure 5 is the front view of the nut in example 2.

[0026] Figure 6 is the front view of the first tooling in example 3.

[0027] Figure 7 is the front view of the first tooling in example 2.

[0028] In the figure: 1.0, special flange test plate, 2.0, connecting assembly, 2.1, nut, 100, valve flange, 1, first tooling, 11, first ear hole, 2, second tooling assembly, 21, half ring body, 22, second ear hole, 23, half ear hole, 24, boss, 3, connecting assembly, 31, bolt, 32, nut, 33, ring groove, 4, connecting hole one, 5, connecting hole two, 6, internal thread hole, 7, compensating gasket layer, 71, radiation groove, 8, lead pipe, 9, via hole. DETAILED DESCRIPTION

[0029] The utility model will be further described below in combination with the drawings and specific embodiments.

[0030] Example 1

[0031] As Figure 2 shown, the utility model relates to a kind of cryogenic ball valve pressure and sealing test tool, comprising: first tooling 1;Second tooling assembly 2, including two separable half ring body 21;Wherein, the first tooling 1 is disc type piece, and second tooling assembly 2 can be spliced into disc type piece;Wherein, the first tooling 1 and second tooling assembly 2 can be clamped in the front and back two sides of the valve flange to be tested, and be connected outside the outer edge of valve flange.

[0032] As Figure 3 、 4As shown, the test tool of the embodiment is a combined structure. The first tool 1 is a disc-shaped fixed reference element, and its outer diameter is larger than the maximum theoretical outer diameter of the valve flange to be tested. The second tool assembly 2 is composed of two symmetrical half-ring bodies 21. The inner arc surface of each half-ring body 21 has a curvature radius matching the outer circumference of the valve flange. When the two half-ring bodies 21 are combined, the annular structure formed by the combination is coaxially arranged with the first tool 1, and the axial compression is achieved through the connecting assembly 3 distributed outside the outer edge of the flange. The end surface of the first tool 1 is processed with a first axial connecting hole group uniformly distributed along the circumference. The hole spacing is determined according to the maximum bolt 31 hole center distance of the commonly used flange standard. The outer edge of each half-ring body 21 of the second tool assembly 2 is correspondingly provided with a second axial connecting hole group, and the hole distribution forms a corresponding relationship with the first axial connecting hole group. In actual assembly, the operator only needs to ensure that the circumference of the first axial connecting hole group of the first tool 1 is larger than the outer diameter of the valve flange to be tested. At this time, the circumference of the second axial connecting hole group corresponding to the first axial connecting hole group is thus formed. Therefore, by tightening the connecting holes 4 and 5 at the corresponding positions through the connecting assembly 3, the first tool 1 and the second tool assembly 2 can form a clamping structure outside the flange.

[0033] The first ear holes 11 symmetrically arranged on the two radial sides of the first tool 1 and the second ear holes 22 formed after the combination of the second tool assembly 2 constitute auxiliary connecting points. The half-ear holes 23 at the combined surface of the half-ring bodies 21 form a complete through-hole structure after combination, and the hole diameter is larger than the diameter of the standard bolt 31 to provide an adjustment allowance. The connecting assembly 3 adopts a double-nut 32 locking structure. After the bolt 31 rod passes through the ear hole, the two end nuts 32 abut against the outer end surfaces of the first tool 1 and the second tool assembly 2, respectively. This external pressure method makes the tightening force directly act on the combined surface rather than the flange sealing surface, avoiding the damage to the sealing surface caused by the bolt 31 penetrating the flange body in the traditional test tool. The combined surface of the split half-ring body 21 is designed as a plane fit, and the contact surface roughness is controlled below Ra3.2 to ensure effective fitting under low temperature conditions.

[0034] The core advantage of the tool disclosed in the embodiment is that multiple specifications can be adapted through modular combination. When facing different flange standards, only the tightening position of the connecting hole group needs to be adjusted to complete the test plate configuration, without the need to replace the whole tool. For example, for DN200-CL300 and DN200-PN16 two specifications of flanges, although there is a difference in the bolt 31 hole center distance, by selecting the connecting holes at the corresponding positions in the first axial connecting hole group for tightening, the same set of tools can meet the test requirements of the two standards. The detachable feature of the split half-ring body 21 enables the tool to adapt to the size tolerance of the flange outer diameter. When the actual outer diameter of the flange is smaller than the theoretical maximum value, the gap at the combined surface of the half-ring body 21 can be eliminated by adjusting the bolt 31 pre-tightening force.

[0035] In addition, the first tooling 1 and the second tooling assembly 2 form a three-point positioning system through the connection of the first connection hole 4 and the second connection hole 5 and the connection points of the auxiliary ear hole, ensuring that the tooling maintains stable coaxiality when bearing the test pressure.

[0036] The first tooling 1 and the second tooling assembly 2 are respectively provided with a through-hole 9, and the inner diameter of the through-hole 9 is coaxially aligned with the through hole of the valve to be tested. The inner wall of the through-hole 9 is processed with an annular step structure for installing the guide pipe 8. The front end of the guide pipe 8 is provided with an outer flange, which is connected with the inner flange of the step of the through-hole 9 through the bolt 31 to realize sealing connection, and the rear end is connected with the external test pipeline through the quick release joint, ensuring that the fluid medium is uniformly injected along the center line direction of the valve.

[0037] During assembly, the operator inserts the guide pipe flange into the tooling through-hole 9 and aligns the circumferential direction angle using the positioning pin. A 1.5-2mm annular gap is reserved between the inner wall of the through-hole 9 and the outer wall of the guide pipe, which is filled with a flexible graphite woven layer that can still maintain a sealed state during low-temperature shrinkage.

[0038] During the test process, the external pressurizing equipment injects test medium into the guide pipe through the quick release joint. When the medium flows through the internal channel of the guide pipe, its flow direction is completely coincident with the axis of the valve through hole, avoiding uneven pressure distribution caused by deflection. When the test pressure reaches the set value, the coaxial structure of the through-hole 9 and the guide pipe ensures that the flange connection part bears pure axial load, eliminating the interference of lateral force on the clamping stability of the tooling. Under low-temperature working conditions of-196℃, the shrinkage of the tooling material reduces the inner diameter of the through-hole 9, and the gap between the guide pipe flange and the step of the through-hole 9 is also reduced. The plastic deformation of the metal winding gasket at low temperature further fills the micro-shrinkage gap.

[0039] The structure realizes quick switching of the test pipeline through the combination design of the center through-hole 9 and the quick release joint, meeting the test requirements of different media. In addition, the combination sealing scheme of the flexible gap compensation layer and the metal gasket effectively solves the leakage problem caused by the shrinkage rate difference of metal parts under extreme temperature difference.

[0040] In the implementation process, the operator first attaches the first tool 1 to the open end surface of the valve flange to be tested, ensuring that the disc-shaped structure completely covers the flange sealing surface. Then, the two half-ring bodies 21 of the second tool assembly 2 are arranged symmetrically along the outer circumference of the flange, and the initial positioning is achieved by the cooperation of the inner arc surface and the curved surface of the flange outer edge. At this time, attention should be paid to the uniform distribution of the gap between the spliced surfaces of the half-ring bodies 21, ensuring that the two half-ring bodies 21 can be spliced to form the internal threaded hole 6. Then, the bolt 31 is sequentially inserted through the connecting hole one 4 of the first axial connecting hole group and the corresponding connecting hole two 5 of the second tool assembly 2, at this time the rod body of the bolt 31 is located on the outer side of the flange, which makes the entire tool cover the outside of the valve, avoiding interference with the internal flow passage of the valve. The torque wrench is used to tighten the bolt 31 in three times of increasing torque in diagonal order, ensuring that the first tool 1 stably seals the valve port flange.

[0041] After completing the fastening of the main connecting hole group, the auxiliary ear hole connecting points on the two sides need to be processed synchronously. A special long bolt is inserted through the first ear hole 11 and the spliced second ear hole 22. Since the second ear hole 22 is composed of two half-ring bodies 21, the hole diameter is designed to consider the assembly tolerance, which is usually 1-2 mm larger than the standard bolt diameter to allow for slight adjustment. During the tightening process, the two side nuts 32 are rotated synchronously to prevent the half-ring body 21 from being deflected due to one-sided overtightening.

[0042] Before the test system is pressurized, low-temperature pre-cooling treatment is performed. The assembled tool together with the valve is placed in a low-temperature environment, and the temperature is lowered at a rate not greater than 5℃ / min to the target temperature and maintained for 30 minutes, allowing the components to fully shrink and reach a stable state. During this process, the planar spliced surface of the split half-ring body 21 can maintain close contact at low temperature due to the machining precision control, and the roughness Ra3.2 of the planar cooperation can effectively inhibit the micro-leakage caused by local stress concentration.

[0043] In actual application scenarios, the connecting assembly 3 of the test tool is completely independent of the bolt hole distribution of the flange being tested. The axial connecting hole group of the first tool 1 and the second tool assembly 2 is arranged in the extended area outside the outer edge of the flange, and the hole layout is based on the maximum outer diameter design covering various types of flanges under the target caliber. When operating, as long as the outer diameter of the flange being tested belongs to CL300, PN16 or PN25 standard, and is within the preset interval, the same tool can be used to complete the clamping.

[0044] In implementation, the technician will first attach the first tool 1 to the front end surface of the flange, then symmetrically buckle the two half-ring bodies 21 along the outer periphery of the flange. After splicing, the radial contraction force is applied through the bolts of the outer connecting assembly 3, so that the half-ring body 21 forms an interference fit with the outer circle of the flange. The first axial connecting hole group is uniformly distributed along the outer periphery of the first tool 1, and the hole spacing is designed according to the bolt distribution circumference of the maximum expected flange outer diameter. During the tightening process, the operator selects the connecting hole group closest to the flange edge according to the actual size of the flange outer diameter, and applies force from the outside to make the half-ring body 21 shrink towards the center until it is in close contact with the outer circle of the flange.

[0045] For the thickness difference caused by the change of the pressure rating of the flange, the self-adaptive compensation is realized through the double-nut 32 locking structure. When the connecting bolt passes through the corresponding hole position of the first tool 1 and the second tool assembly 2, the screwing depth of the two end nuts 32 can be flexibly adjusted according to the flange thickness. In this embodiment, the tool covers the pressure rating requirements of CL150 to CL900. In a low-temperature environment of -196°C, since the connecting assembly 3 is completely located on the outside of the flange, the cold bridge effect caused by the through-flange bolt hole in the traditional test tool is avoided, and the actual heat conduction loss is significantly reduced.

[0046] Embodiment 2

[0047] As shown in Figure 5 , 7 In this embodiment, half-ear holes 23 structures are symmetrically arranged at the edges of the spliced surfaces of the two half-ring bodies 21, and the axis direction is consistent with the radial direction of the flange. The inner wall of each half-ear hole 23 is processed with a split thread, and the thread profile is consistent with the engagement requirements of the standard thread, but only covers a semicircular range. When the two half-ring bodies 21 are accurately spliced through the positioning pin, the half-ear holes 23 on both sides form a complete cylindrical through hole, and the split thread on the inner wall of the through hole forms a continuous spiral lead in three-dimensional space. The entrance end of the threaded hole is processed with a complete annular boss 24, and the outer surface of the boss 24 is tapered, forming a chamfer structure with the spliced surface at a specific angle. The end surface of the nut 32 matched therewith is provided with a ring groove 33, and the inner wall taper of the ring groove 33 is complementary to the outer surface taper of the boss 24, forming a mutual nesting geometric relationship.

[0048] During the assembly process, the operator needs to ensure that the split threads of the two half-rings 21 are completely aligned in the axial and circumferential directions. When the bolt is screwed into the split threaded hole 6, the load distribution of the thread profile on the two half-rings 21 tends to be symmetrical, effectively avoiding unilateral stress concentration. The taper surface cooperation of the boss 24 and the ring groove 33 produces a double effect when the nut is tightened: on the one hand, the radial component force generated by the taper surface contact forces the two half-rings 21 to shrink towards the center of the split surface, eliminating the assembly gap; on the other hand, the axial component force presses the nut end face against the outer side plane of the half-ring 21, forming a multi-stage sealing interface. Under low temperature working conditions, the shrinkage of the half-ring 21 material increases the contact pressure of the taper surface of the boss 24 and the ring groove 33, and the interference fit of the nested structure further enhances the sealing effect.

[0049] In actual assembly, during the nut tightening process, the ring groove 33 gradually fits into the boss 24, and the taper surface contact area expands from local to full circumference. When the specified torque is reached, the outer taper surface of the boss 24 and the inner taper surface of the ring groove 33 form a full circumferential line contact, and at the same time the nut end face and the outer side plane of the half-ring 21 realize face contact. This structure can improve the self-adaptive sealing capability in low temperature environment. As the temperature drops, the shrinkage of the half-ring 21 material increases the compression force between the split surfaces, and the symmetrical load distribution characteristics of the split threads can maintain the integrity of the threaded connection. The taper surface cooperation of the boss 24 and the ring groove 33 produces a dynamic compensation effect when the temperature changes: when the split surface tends to separate slightly due to material shrinkage, the radial compression force of the taper surface contact area increases, forming a self-reinforced sealing mechanism. Actual tests show that this structure can maintain stable sealing performance after experiencing multiple temperature cycles, and repeated disassembly and assembly will not cause significant wear to the threaded hole.

[0050] For different specifications of flange test requirements, different taper boss-ring groove 33 assemblies can be replaced to achieve rapid adaptation. For example, a smaller taper angle matching pair can be selected for high pressure working conditions to increase contact pressure, while a larger taper angle structure can be used for normal pressure working conditions to reduce assembly difficulty.

[0051] Example 3

[0052] As Figure 6As shown, in the embodiment, the inner end surface of the first tool 1 is provided with a compensating gasket layer 7. When the working temperature drops, the compensating gasket layer 7 expands and compensates the gap between the first tool 1 and the valve flange. The compensating gasket layer 7 includes at least one radial distribution radiation slot 71. In the embodiment, the compensating gasket layer 7 is a low-temperature memory metal part. Specifically, the compensating gasket layer 7 is composed of three layers of superimposed nickel-titanium alloy sheets, and the thickness is controlled within the range of 0.8-1.2 mm. The surface of the alloy sheet is processed with six radial through grooves, which are distributed at equal angles. The gasket layer is allowed to produce controllable radial extension when it shrinks in the axial direction, so as to avoid the warping deformation of the overall structure due to thermal stress concentration. The compensating gasket layer 7 is fixed to the first tool 1 base body through a vacuum brazing process, and the outer diameter is consistent with the diameter of the tool end surface, and the inner diameter is slightly larger than the valve diameter to avoid the sealing surface area. When the test temperature drops from room temperature to -196℃, the nickel-titanium alloy undergoes a phase change from austenite to martensite, resulting in a radial expansion of 0.3-0.5% of the sheet layer, which exactly compensates the 0.2-0.4 mm axial gap formed due to the shrinkage of the stainless steel tool. The through hole 9 lead pipe is arranged at the center axis position of the tool, and the inner diameter size is larger than the diameter of the valve to be tested, and a flange type quick release connector is adopted to realize the quick connection with the external test pipeline.

Claims

1. A cryogenic ball valve pressure and seal test tool, characterized by, The utility model relates to a low temperature ball valve pressure and seal test tool, including: A first tool; A second tool assembly including two separable half ring bodies; Wherein, the first tool is a disc type piece, and the second tool assembly can be spliced into a disc type piece; Wherein, the first tool and the second tool assembly can be clamped on the front and back sides of the valve flange to be tested and connected outside the outer edge of the valve flange.

2. The cryogenic ball valve pressure and seal test tool of claim 1, wherein: The first tool is provided with a first axial connecting hole group along the outer edge, the second tool assembly includes a second axial connecting hole group corresponding to the first axial connecting hole group, and a connecting assembly is arranged between the first axial connecting hole group and the second axial connecting hole group, and the connecting assembly is installed outside the outer edge of the valve flange to be tested.

3. The cryogenic ball valve pressure and seal test tool of claim 2, wherein: The first axial connecting hole group includes a plurality of connecting holes one arranged uniformly in the circumferential direction, the second axial connecting hole group includes a plurality of connecting holes two corresponding to the connecting holes one, and the connecting assembly connects and fixes the corresponding connecting holes one and connecting holes two.

4. The cryogenic ball valve pressure and seal test tool of claim 3, wherein: The connecting assembly includes a bolt penetrating the connecting hole one and the connecting hole two corresponding to the connecting hole one, and further includes two nuts respectively arranged at the two ends of the bolt, and the two nuts are respectively abutted against the outer end surface of the first tool and the outer end surface of the second tool assembly.

5. The cryogenic ball valve pressure and seal test tool of claim 2, wherein: The first tool is provided with a first ear hole on the two sides in the radial direction, the second tool assembly includes a second ear hole arranged corresponding to the first ear hole, the second ear hole is formed by splicing the half ear holes arranged on the two half ring bodies, and a connecting assembly is arranged between the first ear hole and the second ear hole.

6. The low temperature ball valve pressure and seal test tool according to claim 5, wherein: The two half ear holes are respectively provided with split threads, when the two half ring bodies are spliced, the split threads on the two sides are combined to form a complete internal thread hole, the hole opening of the internal thread hole is formed with an annular boss, the nut end surface of the connecting assembly is provided with an annular groove corresponding to the annular boss, and the split surfaces are sealed by nesting the annular groove and the annular boss when being screwed.

7. The low temperature ball valve pressure and seal test tool according to any one of claims 1-6, wherein: The inner end surface of the first tool is provided with a compensating gasket layer, when the working temperature decreases, the compensating gasket layer expands and compensates the gap between the first tool and the valve flange; the compensating gasket layer includes at least one radial distribution radiation groove.

8. The cryogenic ball valve pressure and seal test tool of claim 1, wherein: The first tool and the second tool assembly are both provided with a through hole at the center, and a guide pipe can be arranged in the through hole.

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