Low-temperature knife-shaped gate valve structure

Abstract

The utility model discloses a low-temperature knife-shaped gate valve structure, belongs to the technical field of valves, and aims to solve the problem that a valve seat and a gate plate are difficult to maintain reliable sealing due to the fact that a conventional knife-shaped gate valve is affected by a low-temperature medium and expands with heat and contracts with cold. Comprising a valve body, two valve seat assemblies are symmetrically installed in a medium channel of the valve body, each valve seat assembly comprises an annular end cover, a check ring and a valve seat body which are sequentially arranged from outside to inside, the annular end covers are in threaded connection with the valve body, the annular end covers abut against the check rings through disc springs, and the valve seat bodies are sleeved with sealing rings. The valve seat body is in sliding sealing fit with the hole wall of the medium channel through a sealing ring, a sealing ring is embedded in the end face of the inner side of the valve seat body, the valve seat body is a metal component, and the sealing ring is a non-metal component. Through the pre-tightening force effect of the disc spring, compensation thrust can be provided for the valve seat body, and the valve seat body can still be matched with the flashboard all the time.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of valve, especially relates to a knife gate valve structure applied to low temperature pressure container storage tank, is used as cut-off isolation device. BACKGROUND

[0002] The knife gate valve is mainly applied to the industries of slurry, dust, fiber, papermaking, petrochemical, mine, drainage and food, and realizes the purposes of opening and closing as the gate plate rises or falls along the valve rod.

[0003] The conventional flat gate valve structure is long, bulky and heavy, and is inconvenient to install on the pressure container such as thin plate storage tank, and the conventional knife gate valve is usually provided with an oval valve cover and a U-shaped gasket, the valve body and the valve cover are sealed through the U-shaped gasket, but the compression amount of the U-shaped gasket is uneven in all directions, and leakage is very easy at low temperature, in addition, when circulating low temperature medium, the valve seat is easy to produce thermal expansion and cold shrinkage due to the influence of the medium, so that the valve seat and the gate plate are difficult to keep reliable sealing. CONTENT OF THE UTILITY MODEL

[0004] The utility model discloses a low temperature knife gate valve structure, to solve the problem that the conventional knife gate valve is affected by low temperature medium and produces thermal expansion and cold shrinkage, and the valve seat and the gate plate are difficult to keep reliable sealing.

[0005] A low temperature knife gate valve structure, including valve body, valve seat assembly, gate plate, valve cover and valve rod, the valve body is equipped with medium channel, the valve cover is installed at the upper end of the valve body, the gear box is fixed on the valve cover through the support, the lower end of the valve rod is connected with the gate plate, the upper end of the valve rod passes through the valve cover and is connected with the output end of the gear box;

[0006] Two valve seat assemblies are symmetrically installed in the medium channel, the two ends of the medium channel are defined as outer, and the middle part of the channel is defined as inner, the valve seat assembly includes annular end cover, retainer and valve seat body arranged in sequence from outer to inner, the annular end cover is threadedly connected with the valve body, the annular end cover and the retainer are abutted through disc spring, the valve seat body is sleeved with sealing ring, the valve seat body and the hole wall of the medium channel are slidingly and sealingly matched through the sealing ring, the inner side surface of the valve seat body is inlaid with sealing ring, the valve seat body is a metal member, and the sealing ring is a non-metal member.

[0007] Further, the input end of the gear box is connected with the hand wheel.

[0008] Further, the top end of the valve cover is provided with a packing gland, the valve rod passes through the valve cover from the packing gland, the packing gland comprises a first counterbore coaxially connected with a second counterbore, the diameter of the second counterbore is smaller than the diameter of the first counterbore, the packing gland is provided with a packing assembly, the packing assembly comprises graphite packing, an L-shaped gasket ring and a plurality of V-shaped packings, the plurality of V-shaped packings are stacked in sequence, the L-shaped gasket ring comprises a straight cylinder portion and a flange portion connected with the top end of the straight cylinder portion, the flange portion is pressed on the bottom surface of the first counterbore by the graphite packing, and the straight cylinder portion presses the plurality of V-shaped packings on the bottom surface of the second counterbore; the valve cover and the valve rod are in sliding sealing cooperation through the packing assembly.

[0009] Further, the valve cover is provided with a sliding bearing.

[0010] Further, the sealing ring is in interference fit with the corresponding valve seat body.

[0011] Further, the inner end face of the annular end cover is provided with an annular limiting protrusion, and the disc spring is sleeved on the limiting protrusion.

[0012] Further, the upper end face of the valve body is provided with a sunken groove, and the sunken groove is provided with a sealing gasket; the sealing gasket is in the shape of a racetrack; and the valve cover and the valve body are in sealing connection through the sealing gasket.

[0013] Further, the sealing gasket is made of graphite or PTFE plastic.

[0014] Compared with the prior art, the utility model has the advantages that:

[0015] 1. By screwing the annular end cover, the position of the sealing surface of the valve seat assembly can be adjusted, so that the valve seat assembly and the gate plate can be easily kept in a sealing state, and debugging and maintenance are facilitated; the pre-tightening force of the disc spring can provide a compensating thrust for the valve seat body; and even when thermal expansion and contraction occurs due to low-temperature medium, the valve seat body can still be kept in cooperation with the gate plate. The utility model is provided with floating valve seat bodies on the upstream and downstream of the medium channel, the two valve seat bodies are symmetrical, and bidirectional sealing can be realized.

[0016] 2. The utility model is provided with a valve cover, the U-shaped packing sealing structure of the traditional knife-type gate valve is converted into the circular packing assembly sealing structure in the utility model through the valve cover, the main sealing is V-shaped packing made of PTFE material, the second graphite packing is arranged on the L-shaped gasket ring, and the functions of fire prevention and double sealing are realized. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is the front view of the utility model;

[0018] Figure 2 is the left view of the utility model;

[0019] Figure 3is Figure 1 an enlarged view of B in Fig.

[0020] Figure 4 is Figure 1 an enlarged view of A in Fig.

[0021] Figure 5 is a schematic view of a seal.

[0022] In the figure, 1. valve body, 2. valve seat assembly, 3. gate plate, 4. seal, 5. valve cover, 6. valve stem, 7. packing assembly, 8. support, 9. gear box, 10. ring end cover, 11. disc spring, 12. retainer, 13. seal ring, 14. gasket, 15. valve seat body, 16. seal ring, 17. gland, 18. V-shaped packing, 19. sliding bearing, 20. L-shaped gasket ring, 21. graphite packing. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the utility model more clear and obvious, the following will describe the utility model through specific embodiments shown in the drawings. However, it should be understood that these descriptions are only exemplary, and not to limit the scope of the utility model. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the utility model.

[0024] The connection referred to in the utility model is divided into fixed connection and detachable connection, the fixed connection is namely non-detachable connection including but not limited to edge folding connection, rivet connection, bonding connection and welding connection and other conventional fixed connection modes, the detachable connection includes but is not limited to bolt connection, buckle connection, pin connection and hinge connection and other conventional detachable modes, when not explicitly limited to specific connection mode, at least one connection mode to realize the function can be found in the existing connection mode by default, and the person skilled in the art can select it according to the needs. For example: fixed connection selects welding connection, detachable connection selects bolt connection.

[0025] The utility model will be further described in detail below in combination with the drawings, and the following embodiments are the explanation of the utility model, and the utility model is not limited to the following embodiments.

[0026] Embodiment: as Figures 1-5 shown, a low-temperature knife type gate valve structure, including valve body 1, valve seat assembly 2, gate plate 3, valve cover 5 and valve stem 6, valve body 1 is equipped with medium passage, valve cover 5 is installed on the upper end of valve body 1, gear box 9 is fixed on valve cover 5 through support 8, the lower end of valve stem 6 is connected with gate plate 3, the upper end of valve stem 6 passes through valve cover 5 and is connected with the output end of gear box 9;

[0027] Two valve seat assemblies 2 are symmetrically installed in the medium channel. The two ends of the medium channel are defined as the outer part and the middle part of the channel is defined as the inner part. The valve seat assembly 2 includes an annular end cap 10, a retaining ring 12 and a valve seat body 15 arranged sequentially from the outside to the inside. The annular end cap 10 is threaded to the valve body 1. The annular end cap 10 and the retaining ring 12 are abutted by a disc spring 11. A sealing ring 13 is sleeved on the valve seat body 15. The valve seat body 15 and the hole wall of the medium channel are slidably sealed by the sealing ring 13. A sealing ring 16 is embedded on the inner end face of the valve seat body 15. The valve seat body 15 is a metal component and the sealing ring 16 is a non-metallic component.

[0028] By screwing on the annular end cap, the sealing surface position of the valve seat assembly 2 can be adjusted, making it easy for the valve seat assembly 2 and the gate 3 to maintain a sealed state, which is convenient for debugging and maintenance. Through the preload of the disc spring 11, a compensating thrust can be provided to the valve seat body 15. Especially when thermal expansion and contraction occur due to low temperature medium, the valve seat body 15 can still maintain a fit with the gate 3.

[0029] The valve seat body 15 and the sealing ring 16 form a metal and non-metal combination seal against the gate 3. The inner end face of the sealing ring 16 protrudes slightly from the inner end face of the valve seat body 15. When low-pressure medium flows in the medium channel, the two end faces of the gate 3 respectively slide and seal with the inner end faces of the two sealing rings 16. When high-pressure medium flows in the medium channel, the valve seat body 15 is subjected to a greater thrust. While the valve seat body 15 and the gate 3 are in close contact and sealing, the sealing ring 16 is squeezed and deformed. The end face of the gate 3 slides and seals with the valve seat body 15 and the sealing ring 16 on the same side.

[0030] This utility model has floating valve seat bodies 15 at the upstream and downstream of the medium channel, and the two valve seat bodies 15 are symmetrical, which can achieve bidirectional sealing.

[0031] The input end of gearbox 9 is connected to the handwheel.

[0032] A stuffing box is provided at the top of the valve cover 5. The valve stem 6 passes through the stuffing box through the valve cover 5. The stuffing box includes a first countersunk hole and a second countersunk hole that are coaxially connected. The diameter of the second countersunk hole is smaller than the diameter of the first countersunk hole. A stuffing assembly 7 is provided inside the stuffing box. The stuffing assembly 7 includes graphite packing 21, an L-shaped gasket 20 and several V-shaped packings 18. The several V-shaped packings 18 are stacked in sequence. The L-shaped gasket 20 includes a straight cylindrical part and a flange part connected to the top of the straight cylindrical part. The cross-section of the L-shaped gasket 20 is L-shaped. The gland 17 presses the flange part onto the bottom surface of the first countersunk hole through the graphite packing 21. The straight cylindrical part presses the several V-shaped packings 18 onto the bottom surface of the second countersunk hole. The valve cover 5 and the valve stem 6 are slidably sealed together through the stuffing assembly 7.

[0033] The utility model discloses a valve cover 5, the U-shaped packing seal structure of traditional knife type gate valve is converted into the packing assembly 7 seal structure of the circle of the utility model through valve cover 5, and the main seal is the V-shaped packing 18 of PTFE material, is equipped with the second graphite packing 21 on L-shaped gasket ring 20, plays the role of fire prevention and double seal.

[0034] The sliding bearing 19 is arranged on the valve cover 5, and the valve cover 5 is slidably guided and positioned to the valve rod 6 through the sliding bearing 19.

[0035] The sealing ring 16 is in interference fit with the corresponding valve seat body 15.

[0036] The inner end face of the annular end cover 10 is provided with an annular limiting protrusion, and the disc spring 11 is sleeved on the limiting protrusion.

[0037] The upper end face of the valve body 1 is provided with a sunken groove, and the sunken groove is provided with the sealing gasket 4; the sealing gasket 4 is in the shape of a racetrack, and the valve cover 5 and the valve body 1 are sealingly connected through the sealing gasket 4; and the sunken groove has a positioning effect, so that the sealing gasket 4 is stably arranged between the valve cover 5 and the valve body 1.

[0038] The sealing gasket 4 is a graphite component or a PTFE plastic component.

[0039] The above embodiment is only an exemplary description of the utility model, and does not limit the protection scope thereof; the skilled in the art can also change the utility model in part, as long as the spirit and essence of the utility model are not exceeded, and the utility model is within the protection scope.

Claims

1. A low-temperature knife gate valve structure, comprising a valve body (1), a valve seat assembly (2), a gate plate (3), a bonnet (5) and a valve stem (6), the valve body (1) is provided with a medium channel, the bonnet (5) is installed on the upper end of the valve body (1), a gear box (9) is fixed on the bonnet (5) through a support (8), the lower end of the valve stem (6) is connected with the gate plate (3), the upper end of the valve stem (6) penetrates through the bonnet (5) and is connected with the output end of the gear box (9); characterized in that Two valve seat assemblies (2) are symmetrically installed in the medium channel, the two ends of the medium channel are defined as outer, and the middle part of the channel is defined as inner, the valve seat assembly (2) comprises an annular end cover (10), a check ring (12) and a valve seat body (15) which are sequentially arranged from outer to inner, the annular end cover (10) is threadedly connected with the valve body (1), the annular end cover (10) is abutted with the check ring (12) through a disc spring (11), the valve seat body (15) is sleeved with a sealing ring (13), the valve seat body (15) is in sliding sealing cooperation with the hole wall of the medium channel through the sealing ring (13), a sealing ring (16) is embedded on the inner side end face of the valve seat body (15), the valve seat body (15) is a metal component, and the sealing ring (16) is a non-metal component.

2. A cryogenic gate valve structure according to claim 1, characterized in that: The input end of the gear box (9) is connected with a hand wheel.

3. A cryogenic gate valve structure as claimed in claim 1, wherein: The top end of the bonnet (5) is provided with a stuffing box, the valve stem (6) penetrates through the bonnet (5) through the stuffing box, the stuffing box comprises a first counterbore and a second counterbore which are coaxially connected, the diameter of the second counterbore is smaller than that of the first counterbore, a stuffing assembly (7) is arranged in the stuffing box, the stuffing assembly (7) comprises graphite stuffing (21), an L-shaped gasket ring (20) and a plurality of V-shaped stuffing (18), the plurality of V-shaped stuffing (18) are sequentially stacked, the L-shaped gasket ring (20) comprises a straight cylinder portion and a flange portion connected with the top end of the straight cylinder portion, a gland (17) presses the flange portion on the bottom surface of the first counterbore through the graphite stuffing (21), the straight cylinder portion presses the plurality of V-shaped stuffing (18) on the bottom surface of the second counterbore, and the bonnet (5) is in sliding sealing cooperation with the valve stem (6) through the stuffing assembly (7).

4. The cryogenic gate valve structure of claim 1, wherein: A sliding bearing (19) is arranged on the bonnet (5).

5. The cryogenic gate valve structure of claim 1, wherein: The sealing ring (16) is in interference fit with the corresponding valve seat body (15).

6. A cryogenic gate valve structure as claimed in claim 1, wherein: A ring-shaped limiting protrusion is arranged on the inner end face of the annular end cover (10), and the disc spring (11) is sleeved on the limiting protrusion.

7. A cryogenic gate valve structure according to any one of claims 1-6, characterized in that: A counterbore is arranged on the upper end face of the valve body (1), a sealing gasket (4) is arranged in the counterbore, the sealing gasket (4) is in the shape of a runway, and the bonnet (5) and the valve body (1) are sealingly connected through the sealing gasket (4).

8. A cryogenic gate valve structure according to claim 7, characterized in that: The sealing gasket (4) is a graphite component or a PTFE plastic component.

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