Low-temperature ball valve packing sealing structure and low-temperature ball valve

Abstract

A low-temperature ball valve packing sealing structure and a low-temperature ball valve comprise a valve rod heightening support arranged on the outer side of a valve rod, a packing box is arranged on the valve rod heightening support, packing is arranged in the packing box, and the low-temperature ball valve packing sealing structure further comprises a freezing structure arranged in the packing box at the bottom of the packing. The freezing structure can be frozen and expanded when making contact with a low-temperature medium leaked due to failure of the lip-shaped sealing ring, the packing is pushed to be further pre-tightened and sealed, by means of the freezing structure, when the lip-shaped sealing ring is intact, the graphite packing can still play a conventional sealing role, and the valve can also pass various fireproof tests; meanwhile, the operation torque of the valve cannot be increased for the valve, any performance of the valve cannot be affected by the freezing structure, and when the lip-shaped sealing ring loses efficacy and leaks, the freezing structure can freeze and expand when making contact with a low-temperature medium, the filler is pushed to be further pre-tightened and sealed, the sealing force is automatically increased, the filler can be automatically pre-warned, and sealing is enhanced; and the process does not need manual intervention.

Description

Technical Field

[0001] The invention relates to the technical field of valves, and in particular to a low-temperature ball valve packing sealing structure and a low-temperature ball valve. Background Art

[0002] Common cryogenic ball valves use a lip seal structure at the elevated part. The cryogenic medium in the valve cavity cannot pass through the lip seal and directly enter the valve stem elevated bracket. The packing part does not directly contact the cryogenic medium and is not easy to freeze. However, this lip seal is very easy to fail to seal when it is switched on and off for a long time under actual low-temperature conditions, causing the bottom of the packing to be filled with cryogenic medium, resulting in packing freezing and valve leakage. In the low-temperature testing and simulation process of large manufacturers, the conclusion that the packing will not freeze is drawn when the lip seal does not fail. However, after the cryogenic valve is switched on and off many times, the lip seal has a high probability of leakage in harsh media. The purpose of raising the height of the cryogenic ball valve is to prevent the packing from freezing and leaking. The matching of valve packing is based on the selection of materials at normal temperature. The compression of the packing in the installed state is adapted to the normal temperature medium. The sealing is achieved on the premise that the packing does not freeze. The leakage of cryogenic liquid oxygen or cryogenic liquid nitrogen cannot be predicted, and manual remediation is difficult to carry out in time. Summary of the invention In order to solve the technical defects in the prior art, the present invention provides a cryogenic ball valve packing sealing structure and a cryogenic ball valve.

[0003] The technical solution adopted by the present invention is: a low-temperature ball valve packing sealing structure, including a valve stem heightening bracket arranged on the outside of the valve stem, a stuffing box is arranged on the valve stem heightening bracket, a stuffing is arranged in the stuffing box, a stuffing gland is arranged on the stuffing box, and also includes: A freezing structure is provided in the stuffing box at the bottom of the stuffing. When the freezing structure contacts the low-temperature medium leaking due to the failure of the lip seal ring, it will freeze and expand, thereby pushing the stuffing to further pre-tighten the seal.

[0004] It also includes a valve stem protection ring, which is arranged between the freezing structure and the valve stem. The valve stem protection ring allows the expansion force of the freezing structure to be transmitted only to the bottom of the packing and will not be applied to the outer diameter of the valve stem.

[0005] The valve stem protection ring is an L-shaped structure, and two sides of the L-shaped structure are respectively arranged between the freezing structure and the valve stem and at the bottom of the freezing structure.

[0006] It also includes a packing thrust ring, which is arranged between the freezing structure and the packing and is used to support the packing and withstand the thrust generated by ice from the freezing structure below.

[0007] The freezing structure includes a fluid state above the freezing point and an ice state when in contact with a low-temperature medium leaking due to a failure of the lip seal.

[0008] The freezing structure is a multi-layer vacuum-sealed vacuum water bag or alcohol bag.

[0009] A cryogenic ball valve comprises a valve body, wherein a ball is arranged in the valve body, a valve stem is connected to the ball, a lip seal is arranged between the valve stem and the valve body, and the valve stem is provided with the cryogenic ball valve packing seal structure.

[0010] The beneficial effects of the present invention are as follows: the present invention provides a low-temperature ball valve packing sealing structure and a low-temperature ball valve, including a valve stem raising bracket arranged on the outside of the valve stem, a stuffing box being arranged on the valve stem raising bracket, a stuffing box being arranged in the stuffing box, and also including a freezing structure, the freezing structure being arranged in the stuffing box at the bottom of the stuffing, the freezing structure will freeze and expand when it contacts the low-temperature medium leaked due to the failure of the lip sealing ring, and push the stuffing to further pre-tighten and seal, the present invention sets up a freezing structure, when the lip sealing ring is intact, the graphite packing can still play a conventional sealing role, the valve can also pass various fire tests, and at the same time will not increase the operating torque of the valve, the existence of the freezing structure will not affect any performance of the valve, when the lip sealing ring fails and leaks, the freezing structure will freeze and expand when it contacts the low-temperature medium, and push the stuffing to further pre-tighten and seal, automatically increase the sealing force, can automatically warn the stuffing, strengthen the sealing, and the process does not require manual intervention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the packing sealing structure of the cryogenic ball valve of the present invention.

[0012] Figure 2 It is a schematic diagram of the structure of an existing cryogenic ball valve.

[0013] Among them, 1-valve stem heightening bracket, 2-stuffing box, 3-packing, 4-packing gland, 5-freezing structure, 6-valve stem protection ring, 7-packing thrust ring, 11-lip sealing ring. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0015] A packing sealing structure of a cryogenic ball valve comprises a valve stem heightening bracket 1 arranged outside a valve stem, a packing box 2 arranged on the valve stem heightening bracket 1, a packing 3 arranged inside the packing box 2, a packing gland 4 arranged on the packing box 2, and a freezing structure 5, which is a vacuum water bag or alcohol bag with multiple layers of vacuum sealing. The freezing structure 5 is arranged in the packing box 2 at the bottom of the packing 3, and the freezing structure 5 will freeze and expand when it contacts the cryogenic medium leaked due to the failure of the lip seal ring. By utilizing the characteristic that the volume of water will expand by 10% when it freezes, when the cryogenic medium passes through the damaged lip seal ring and leaks to this part, the water bag will freeze, pushing the packing to further pre-tighten and seal; and a valve stem protection ring 6 is also included, the valve stem protection ring 6 is arranged between the freezing structure 5 and the valve stem, the valve stem protection ring 6 is an L-shaped structure, and the two sides of the L-shaped structure are respectively arranged between the freezing structure 5 and the valve stem and at the bottom of the freezing structure 5. The valve stem protection ring 6 enables the expansion force of the freezing structure 5 to be transmitted only to the bottom of the packing 3, and will not be applied to the outer diameter of the valve stem. It also includes a packing thrust ring 7, which is arranged between the freezing structure 5 and the packing 3 to support the packing 3 and withstand the thrust generated by the freezing structure 5 below.

[0016] The freezing structure 5 includes a fluid state when it is above the freezing point and an ice state when it contacts a low-temperature medium leaking due to a failure of the lip seal.

[0017] A cryogenic ball valve comprises a valve body, wherein a ball is arranged in the valve body, a valve stem is connected to the ball, a lip seal ring 11 is arranged between the valve stem and the valve body, and the valve stem is provided with the cryogenic ball valve packing seal structure.

[0018] The present invention sets a freezing structure, so that when the lip sealing ring is intact, the graphite packing can still play a conventional sealing role, and the valve can pass various fire tests. At the same time, the operating torque of the valve will not be increased, and the existence of the freezing structure will not affect any performance of the valve. When the lip sealing ring fails and leaks, the freezing structure will freeze and expand when it contacts the low-temperature medium, pushing the packing to further pre-tighten the seal, automatically increasing the sealing force, and can automatically warn the packing and strengthen the seal, and the process does not require human intervention.

[0019] Technical personnel should note that although the present invention has been described according to the above specific implementation methods, the inventive concept of the present invention is not limited to this invention, and any modification using the inventive concept will be included in the scope of protection of this patent.

[0020] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A packing seal structure for a cryogenic ball valve, comprising a valve stem raising bracket (1) arranged outside a valve stem, a stuffing box (2) being arranged on the valve stem raising bracket (1), a stuffing box (3) being arranged inside the stuffing box (2), and a stuffing gland (4) being arranged on the stuffing box (2), characterized in that: Also included are: A freezing structure (5), wherein the freezing structure (5) is arranged in the stuffing box (2) at the bottom of the stuffing (3), and when the freezing structure (5) contacts the low-temperature medium leaking due to the failure of the lip seal ring, it will freeze and expand, thereby pushing the stuffing (3) to further pre-tighten the seal.

2. A cryogenic ball valve packing sealing structure according to claim 1, characterized in that: It also includes a valve stem protection ring (6), which is arranged between the freezing structure (5) and the valve stem. The valve stem protection ring (6) ensures that the expansion force of the freezing structure (5) can only be transmitted to the bottom of the packing (3) and will not be applied to the outer diameter of the valve stem.

3. A cryogenic ball valve packing sealing structure according to claim 2, characterized in that: The valve stem protection ring (6) is an L-shaped structure, and two sides of the L-shaped structure are respectively arranged between the freezing structure (5) and the valve stem and at the bottom of the freezing structure (5).

4. A cryogenic ball valve packing seal structure according to claim 1, characterized in that: It also includes a packing thrust ring (7), which is arranged between the freezing structure (5) and the packing (3) and is used to support the packing (3) while bearing the thrust generated by ice formation from the freezing structure (5) below.

5. A cryogenic ball valve packing seal structure according to claim 1, characterized in that: The freezing structure (5) includes a fluid state when it is above the freezing point and an ice state when it contacts a low-temperature medium leaking due to a failure of the lip seal.

6. A cryogenic ball valve packing seal structure according to claim 5, characterized in that: The freezing structure (5) is a multi-layer vacuum-sealed vacuum water bag or alcohol bag.

7. A cryogenic ball valve, characterized in that: It comprises a valve body, wherein a ball is arranged in the valve body, a valve stem is connected to the ball, a lip seal ring (11) is arranged between the valve stem and the valve body, and the valve stem is provided with the cryogenic ball valve packing seal structure according to claim 1.

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