Double-valve-element closed gate valve

Abstract

The utility model provides a double-valve-element closed gate valve which comprises a valve body, a valve rod, a pressure balance pipe and double valve elements, and the double valve elements are composed of two valve elements arranged in parallel. The two valve cores which are arranged in parallel are wedge type valve cores; a wedge-shaped connector is arranged between the two valve elements and the valve body, the upper portion of the double valve elements and the valve body are fixed through a gland, a sealing gasket is arranged between the gland and the double valve elements, a valve rod is arranged above the gland, and the valve rod and the gland are sealed through a sealing filler pressing sleeve. A pressure balance pipe is arranged in the valve rod, a side hole is formed in the side portion of the pressure balance pipe, and the upper portion of the pressure balance pipe is provided with a residual pressure valve or directly communicated with atmosphere. Vent holes are formed in the bottom of the valve rod. A double-valve-element structure is adopted, the leakage risk of the valve can be effectively reduced when the valve is closed, and the leakproofness of the valve is improved. The pressure balance pipe is arranged in the valve rod, the sealing cavity can be communicated with the outdoor atmosphere through the vent hole and the pressure balance pipe, if leakage liquid exists in the sealing cavity, the leakage liquid can be discharged out of the valve body through the pressure balance pipe, and complete physical isolation of the two ends of the valve is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of fluid control valves, in particular to a double-spool sealed gate valve. Background Art

[0002] A gate valve is a valve that can effectively control the flow of fluid media and is widely used in various fluid transportation and distribution fields such as petroleum, chemical industry, water treatment, and electric power. Its main uses include: cutting off the fluid in the pipeline, controlling the fluid flow rate, and maintaining the pipeline system. The advantages of the gate valve are its simple structure, usually consisting of simple components such as a valve body, a sealing ring, a valve stem, and a handwheel, which is convenient for installation and maintenance. At the same time, since the valve is closed by the valve core, the sealing performance is good and the operation is reliable. Most of the existing wedge gate valves adopt a single-spool structure, and there is a certain risk in the valve tightness. In the switching work between high and low pressure systems, if the high and low area pipelines are connected, it will cause overpressure damage to the low area equipment, and in severe cases, the system may be completely irreparable; in the switching work between a closed system and an open system, if the closed system and the open system are connected and the closed system is higher than the open system, it will cause fluid loss to the open system; in the process of switching the working conditions of public pipelines, if the pipelines under different working conditions are connected, it will lead to fluid short-circuit between the pipelines. To solve the above problems, usually two sets of gate valves and a drain valve need to be set in the pipeline at the present stage to completely isolate the static pressure of different water systems. At this time, the investment cost of the valves increases significantly; at the same time, in the automatic control system design, it is easy to generate deviations in the action switching strategy control of two identical valves adjacent to each other in the same pipeline, and the effect of the automatic control system is difficult to guarantee.

[0003] It is found through retrieval that the invention patent with the application number 201410441711.2 discloses an axially expanded double-spool gate valve. The outer ends of the left spool and the right spool are respectively vertical valve flaps perpendicular to their inner convex ends. One side of the lower part of the spool positioning frame is an upright surface, and the other side is a smooth curved surface forming a single-sided wedge. The smooth curved surface faces the inclined surface of the inclined sleeve of the loose sleeve, and one end of the inclined sleeve is an upright surface.

[0004] It is found through retrieval that the invention patent with the application number CN202210373425.1 discloses a gate plate of a telescopic wedge gate valve and its processing method, characterized in that: sealing rings are respectively embedded on the left gate plate and the right gate plate to form a sealing pair with the valve seat, and a telescopic device is arranged between their contact surfaces. When opening the valve, the left gate plate and the right gate plate first loosen and contact the valve seat and then lift. When closing the valve, the left gate plate and the right gate plate first descend in place and then are expanded by the wedge block to be tightly matched with the valve seat.

[0005] The utility model patent with the application number CN212273101 discloses a fully enclosed gate valve. Its gate plate assembly has a support plate, a left slide plate, a right slide plate and a spring. The left slide plate and the right slide plate are matched in the mounting holes of the support plate, and the spring is arranged between the left slide plate and the right slide plate. The left valve seat has a left baffle, and the right valve seat has a right baffle. Between the left baffle and the right baffle is the moving channel of the gate plate assembly. The left side plane of the left slide plate leans against the right side plane of the left baffle, and the right side plane of the right slide plate leans against the left side plane of the right baffle. The right side plane of the left baffle and the left side plane of the right baffle have blocking parts that cooperate to block both ends of the gate plate flow channel.

[0006] During switching conditions such as high and low pressure system switching conditions, closed system and open system switching conditions, and public pipeline condition switching conditions, it is not allowed to have valve sealing failure. The above three retrieved patents all adopt a movable valve core structure, and the valve core sealing is achieved through the stiffness of the valve core itself or an internal spring. After the valve is started multiple times, the valve core will not close tightly, which does not meet the use requirements. The double-valve-core enclosed gate valve proposed by the present invention can replace the original three sets of valves with only one set of valves. At the same time, the control of the three valve cores is completed by the same transmission mechanism, and the control method is simple and convenient, which can provide a good solution to solve the above problems. Utility Model Content

[0007] In view of the problems in the prior art, the present utility model proposes a double-valve-core enclosed gate valve.

[0008] To achieve the above object, the present utility model provides the following technical solutions:

[0009] A double-valve-core enclosed gate valve includes a valve body, a valve stem, and a pressure balance pipe. The double-valve-core enclosed gate valve further includes a double valve core, and the double valve core is composed of two wedge-shaped valve cores arranged in parallel; the two wedge-shaped valve cores arranged in parallel are both wedge-type valve cores; between the two valve cores and the valve body is a wedge-shaped interface. The double valve core and the valve body are fixed by a gland above. A sealing gasket is arranged between the gland and the double valve core. The valve stem is arranged above the gland, and the valve stem and the gland are sealed by a sealing packing gland; a pressure balance pipe is arranged inside the valve stem. Side holes are opened on the side of the pressure balance pipe, and a residual pressure valve or a direct connection to the atmosphere is arranged on the upper part of the pressure balance pipe; a vent hole is arranged at the bottom of the valve stem.

[0010] As a further improvement of this solution, the valve body is made of cast steel / stainless steel.

[0011] As a further improvement of this solution, a sealing member is arranged at the wedge-shaped interface between the valve body and the double valve core, and the sealing member realizes soft sealing between the double valve core and the valve body.

[0012] As a further improvement of this solution, both the sealing gasket and the sealing packing gland are made of polytetrafluoroethylene.

[0013] As a further improvement of this solution, the seal is made of polytetrafluoroethylene.

[0014] As a further improvement of this solution, the valve stem can be driven by manual, electric or pneumatic power; when the valve stem is driven by electric or pneumatic power, the action time of the actuator is limited within 5 s.

[0015] As a further improvement of this solution, when the valve stem performs the opening action of the valve, the vent hole is arranged inside the packing gland to isolate the air inside the valve body; when the valve stem performs the closing action of the valve, the vent hole is arranged inside the valve body, and the static pressure isolation inside the valve body is realized through the pressure balance pipe.

[0016] Compared with the prior art, the beneficial effects of the present utility model are as follows: The present invention adopts a double-spool structure, which can effectively reduce the leakage risk of the valve and improve the tightness of the valve when the valve is closed. The two spools share one valve stem, and when the valve acts, the actuator pushes the valve stem to move up and down to realize the opening or closing of the valve. The actuator of this valve can be selected as manual, motor or driving compressed air drive mode according to needs. When driven by motor or compressed air, the driving torque needs to be increased, and the valve action time is not more than 5 s, so as to realize rapid shut-off. To prevent the static pressure connection at both ends of the valve due to the failure of the spool seal, the present invention sets a pressure balance pipe inside the valve stem. When the valve is closed, the double spools and the valve body form a sealed cavity. The side port of the pressure balance pipe on the valve stem drops to the sealed valve body, and the sealed cavity can be connected to the outdoor atmosphere through the vent hole and the pressure balance pipe. At this time, if there is leakage liquid in the sealed cavity, it can be discharged from the valve body through the pressure balance pipe, realizing the complete physical isolation at both ends of the valve. Description of the Drawings

[0017] The following further describes the present utility model with reference to the drawings.

[0018] Figure 1 It is a schematic diagram of the overall structure of the present utility model;

[0019] Figure 2 It is a schematic diagram of the overall structure of the present utility model in the closed state of the valve;

[0020] Figure 3 It is a detailed drawing of the valve stem and the pressure balance pipe of the present utility model;

[0021] Figure 4 It is a detailed drawing of the bottom seal of the valve of the present utility model;

[0022] Figure 5 It is a detailed drawing of the top seal and the vent hole of the valve of the present utility model;

[0023] Figure 6 It is a schematic diagram of the structure of the wedge-shaped spool of the present utility model;

[0024] Figure 7 This is the schematic diagram of the double - spool closed gate valve of the present utility model.

[0025] As marked in the figure, 1 - valve body, 2 - double spool, 3 - valve stem, 4 - sealing gasket, 5 - gland, 6 - sealing packing gland, 7 - vent hole, 8 - pressure balance pipe; 9 - side hole; 10 - wedge - shaped interface; 11 - seal. Specific embodiments

[0026] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0027] Embodiment

[0028] As Figures 1-6 shown, this embodiment provides a double - spool closed gate valve, including a valve body 1, a valve stem 3, a pressure balance pipe 8 and a double spool 2. The double spool 2 is composed of two parallel - arranged spools; both of the two parallel - arranged spools are wedge - type spools; between the two spools and the valve body 1 is a wedge - shaped interface 10. The upper part between the double spool 2 and the valve body 1 is fixed by a gland 5. A sealing gasket 4 is arranged between the gland 5 and the double spool 2. The valve stem 3 is arranged above the gland 5. The valve stem 3 and the gland 5 are sealed by a sealing packing gland 6; a pressure balance pipe 8 is arranged inside the valve stem 3. A side hole 9 is opened on the side of the pressure balance pipe 8. A residual pressure valve or is directly vented to the atmosphere above the pressure balance pipe 8; a vent hole 7 is arranged at the bottom of the valve stem 3.

[0029] The valve body 1 is made of cast steel / stainless steel. A seal 11 is arranged at the wedge - shaped interface 10 between the valve body 1 and the double spool 2, and the seal 11 realizes the soft seal between the double spool 2 and the valve body 1. The seal 11 is made of polytetrafluoroethylene.

[0030] Both the sealing gasket 4 and the sealing packing gland 6 are made of polytetrafluoroethylene.

[0031] The valve stem 3 can be driven manually, electrically or pneumatically; when the valve stem 3 is driven electrically or pneumatically, the action time of the actuator is limited within 5 s.

[0032] When the valve stem 3 performs the opening action of the valve, the arranged vent hole 7 is located inside the sealing packing gland 6 to realize the function of isolating air inside the valve body; when the valve stem 3 performs the closing action of the valve, the arranged vent hole 7 is located inside the valve body 1, and the static pressure isolation inside the valve body is realized through the pressure balance pipe 8.

[0033] The vent hole 7 is arranged at the center position of the two valve cores, and the diameter of the vent hole 7 is set according to the fluid density and viscosity. The pressure balance pipe 8 is arranged at the center position of the valve stem 3, and the diameter of the pressure balance pipe 8 is set according to the fluid density and viscosity.

[0034] The double valve core 2 structure is adopted. When the valve is closed, the risk of valve leakage can be effectively reduced, and the valve tightness can be improved. The two valve cores share one valve stem 3. When the valve operates, the actuator pushes the valve stem to move up and down to realize the opening or closing of the valve. The actuator of this valve can be selected as manual, motor or driving compressed air driving mode according to needs. When the motor or compressed air is used for driving, the driving torque needs to be increased, and the valve action time is not more than 5 s, so as to realize rapid shutdown. To prevent the static pressure connection at both ends of the valve caused by the failure of the valve core seal, a pressure balance pipe is arranged in the valve stem of this new type. When the valve is closed, the two valve cores and the valve body form a sealed cavity. The side port of the pressure balance pipe on the valve stem drops to the sealed valve body, and the sealed cavity can be connected to the outdoor atmosphere through the vent hole 7 and the pressure balance pipe 8. At this time, if there is leakage liquid in the sealed cavity, it can be discharged from the valve body through the pressure balance pipe, realizing the complete physical separation at both ends of the valve.

[0035] The working principle is shown in Figure 7 , when the fluid is connected, valve 1 and valve 2 are opened synchronously, and valve 3 is closed. According to Bernoulli's equation, it can be known that:

[0036]

[0037] Note: p is the pressure at a certain point in the fluid, v is the fluid velocity at this point, ρ is the fluid density, g is the acceleration of gravity, and h is the height of the fluid level above this point.

[0038]

[0039] The working pressure of the pipe section between valve 1 and valve 2 = P1 = P2, P3 = outdoor atmospheric pressure. When the fluid is cut off, valve 1 and valve 2 are closed synchronously, and valve 3 is opened. At this time, the fluid velocity v here is 0. According to Bernoulli's equation, it can be known that:

[0040] p1 + ρgh1 = p2 + ρgh2

[0041] P1 = p1 + ρgh1

[0042] P2 = p2. At this time, the height of the fluid level above this point in the pipeline on the right side of valve 2 is 0.

[0043] At this time, P3 = outdoor atmospheric pressure, the working pressure of the pipe section between valve 1 and valve 2 = outdoor atmospheric pressure, P1 > P3, P2 ≥ P3. If the seals of valve 1 and valve 2 fail, the pressures at both ends of the valve group are released to the pipe section between valve 1 and valve 2. This pipe section is in communication with the outdoor atmosphere, and the fluid can be discharged to the outside of the system through valve 3, thereby ensuring that P1 and P2 are completely separated by the outdoor atmospheric pressure.

[0044] When the pipeline needs to be closed, the double valve cores 2 are closed synchronously. At the same time, the vent hole 7 provided on the valve stem is automatically connected to the atmosphere by the stroke setting to completely block the static pressure of the pipeline. When the pipeline is connected, the double valve cores 2 are opened synchronously. At the same time, the vent hole 7 follows the valve stem into the sealing section to cut off the communication between the fluid and the atmosphere through the valve.

[0045] The above content is only an example of the structure of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the structure of the present invention or exceed the scope defined by this claim book, they should all belong to the protection scope of the present invention.

Claims

1. A double-valve core closed gate valve, comprising a valve body (1), a valve stem (3), and a pressure balance pipe (8), characterized in that: The double valve core closed gate valve further comprises a double valve core (2), the double valve core (2) comprising two valve cores arranged in parallel; the two valve cores arranged in parallel are both wedge-type valve cores; a wedge-shaped interface (10) is formed between the two valve cores and the valve body (1); the upper part of the double valve core (2) and the valve body (1) are fixed via a gland (5); a sealing gasket (4) is provided between the gland (5) and the double valve core (2); a valve stem (3) is provided above the gland (5); the valve stem (3) and the gland (5) are sealed via a sealing packing gland (6); a pressure balancing pipe (8) is provided inside the valve stem (3); a side hole (9) is provided on the side of the pressure balancing pipe (8); a residual pressure valve is provided on the upper part of the pressure balancing pipe (8) or the pressure balancing pipe (8) is directly connected to the atmosphere; and a vent hole (7) is provided at the bottom of the valve stem (3).

2. A double valve core closed gate valve according to claim 1, characterized in that: The valve body (1) is made of cast steel / stainless steel.

3. A double valve core closed gate valve according to claim 1, characterized in that: A sealing member (11) is provided at the wedge-shaped interface (10) between the valve body (1) and the double valve core (2), and the sealing member (11) realizes a soft seal between the double valve core (2) and the valve body (1).

4. A double valve core closed gate valve according to claim 1, characterized in that: The sealing gasket (4) and the sealing stuffing gland (6) are both made of polytetrafluoroethylene.

5. A double valve core closed gate valve according to claim 3, characterized in that: The sealing member (11) is made of polytetrafluoroethylene.

6. A double valve core closed gate valve according to claim 1, characterized in that: The valve stem (3) can be driven by manpower, electricity or pneumatics; when the valve stem (3) is driven by electricity or pneumatics, the action time of the actuator is limited to within 5 seconds.

7. A double valve core closed gate valve according to claim 1, characterized in that: When the valve stem (3) is in the valve opening action, the vent hole (7) is located in the sealing packing gland (6), thereby isolating the air inside the valve body; when the valve stem (3) is in the valve closing action, the vent hole (7) is located in the valve body (1), thereby isolating the static pressure inside the valve body through the pressure balance pipe (8).

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