Drain valve

Abstract

The invention belongs to the technical field of valves, and discloses a drain valve which comprises a valve body, a valve seat, a valve cover, a valve rod, a main valve clack, a sacrifice clack and a flow uniformizing sleeve, the sacrifice clack is arranged outside the bottom of the valve rod in a sleeving mode, the main valve clack is arranged outside the upper portion of the sacrifice clack in a sleeving mode, and a spring is arranged between the main valve clack and the sacrifice clack; throttling holes are formed in the side walls of the lower parts of the sacrificial petals; the main valve clack is sleeved with the flow equalizing sleeve, flow equalizing holes are formed in the side wall of the flow equalizing sleeve, and the total area of the flow equalizing holes is larger than that of the throttling holes; a pressure building cavity is formed between the inner wall of the flow equalizing sleeve and the outer wall of the sacrifice petal; a main sealing structure, a first auxiliary sealing structure and a second auxiliary sealing structure are arranged in the pressure building cavity; the service life of the drain valve is effectively prolonged under the condition that the strength and hardness of the surfacing material of the sealing surface are not changed, and meanwhile the good repairability is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of valves and relates to a discharge valve. Background Art

[0002] In the production process of power, metallurgy, petroleum, chemical industry and other industries, it is a common working condition to discharge steam, saturated water or other working media with a large pressure difference. The corresponding pressure difference of these working conditions is above 10MPa. At present, the valve used for large pressure difference discharge working conditions usually uses a stop valve. The stop valve is a common type of valve with the characteristics of simple structure, reliable sealing, flexible operation and small stroke. Its working principle is to drive the valve stem to move up and down through a handwheel or electric device. The valve disc is driven by the valve stem to separate from or press the valve seat to open or close the valve.

[0003] The globe valve has good sealing performance and is usually used as a shut-off valve. It can be divided into normally open, normally closed and frequently opened and closed types according to its operating conditions. The disc of the normally open globe valve is always in the fully open position, the disc sealing surface is far away from the valve seat sealing surface, the medium flows through the valve seat at a normal flow rate, the erosion effect on the sealing surface is weak, and the valve has a long service life; the sealing surface of the normally closed globe valve is always in a tightly fitted state, there is no medium flowing between the disc sealing surface and the valve seat sealing surface, the sealing surface is completely free from medium erosion, and the valve is not easily damaged. However, in the application scenarios of large pressure difference discharge, such as soot blowers, regular sewage discharge and air exhaust piping systems of thermal power boilers, the valve needs to be opened and closed frequently and is accompanied by a large pressure difference. When the valve is opened, the disc and the valve seat are gradually separated, and the medium flows through the circulation ring between the two sealing surfaces. In the initial stage of opening, the cross-section of this circulation ring is extremely narrow, and the large pressure difference is concentrated behind the sealing surface. The medium generates an extremely high flow rate under the action of the large pressure difference, which not only causes serious erosion of the sealing surface, but also causes vibration of the pipeline and produces huge noise. Vice versa, when the discharge is over and the valve is closed, the valve disc gradually approaches the valve seat, and the pressure difference is concentrated behind the sealing surface again, causing erosion of the sealing surface accompanied by vibration and noise. Under such working conditions, the valve is very easy to be damaged. In extreme cases, some valves even leak after only a few openings and closings. It can be seen that under the condition of large pressure difference discharge, when the valve is in the slightly open position, a narrow circulation ring is formed between the sealing surfaces, which has a throttling effect on the medium, and the pressure difference is concentrated behind the sealing surface, resulting in excessively high medium flow rate at the sealing surface, which is the fundamental reason for the damage to the valve sealing surface.

[0004] The existing technical solution is mainly to start with materials, and weld higher strength welding materials on the sealing surface to increase the hardness of the sealing surface to resist the erosion of the medium. This solution can indeed extend the service life of the sealing surface to a certain extent, but it does not solve the problem that the pressure difference is concentrated on the sealing surface when the valve is slightly opened, and the repairability of the sealing surface after damage is poor. In addition, the use of high-strength welding materials also increases the difficulty of welding and processing the sealing surface, so the effect is still not ideal. Summary of the invention

[0005] The present invention provides a discharge valve, which is used to solve the problem in the prior art that a higher strength welding material is needed for surfacing welding on the sealing surface, and the hardness of the sealing surface is improved to resist the erosion of the medium, thereby resulting in poor repairability of the damaged sealing surface, and the use of high-strength welding materials also increases the difficulty of surfacing welding and processing of the sealing surface. The discharge valve can effectively extend its service life without changing the strength and hardness of the surfacing material of the sealing surface, while having good repairability.

[0006] To achieve the above object, the present invention adopts the following technical solution: The present invention provides a discharge valve, comprising a valve body, a valve seat, a valve cover, a valve stem, a main valve disc, a sacrificial disc and a flow equalizing sleeve, wherein a cavity is arranged inside the valve body; the valve seat is installed in the bottom of the valve body; the valve cover is connected to the top of the valve body; the valve cover is provided with a rod hole; the valve stem passes through the rod hole and is movably arranged in the cavity; the main valve disc and the sacrificial disc are both arranged in annular shapes and are movably arranged in the cavity; the sacrificial disc is sleeved outside the bottom of the valve stem, the main valve disc is sleeved outside the upper part of the sacrificial disc, and a spring is arranged between the main valve disc and the sacrificial disc; a throttling hole is arranged on the lower side wall of the sacrificial disc; the flow equalizing sleeve is arranged in the cavity ; The flow balancing sleeve is arranged on the outside of the main valve disc, and the side wall of the flow balancing sleeve is provided with flow balancing holes, and the total area of ​​the flow balancing holes is larger than the total area of ​​the throttling holes; a pressure holding chamber is arranged between the inner wall of the flow balancing sleeve and the outer wall of the sacrificial disc, and a main sealing structure, a first auxiliary sealing structure and a second auxiliary sealing structure are arranged in the pressure holding chamber; the first auxiliary sealing structure and the second auxiliary sealing structure are respectively arranged on both sides of the main sealing structure; the main sealing structure is formed by the contact between the main valve disc and the valve seat, the first auxiliary sealing structure is formed by the contact between the main valve disc and the flow balancing sleeve, and the second auxiliary sealing structure is formed by the contact between the sacrificial disc and the valve seat.

[0007] The discharge valve provided by the present invention is designed for large pressure difference discharge conditions. The flow equalizing sleeve is arranged in the valve body, and the sacrificial flap in the shape of a sleeve with holes is added to the lower part of the main valve flap. The pressure holding chamber is established between the inner wall of the flow equalizing sleeve and the outer wall of the sleeve structure of the sacrificial flap. The main sealing structure is located in the pressure holding chamber, and a first-level auxiliary sealing structure is arranged before and after the main sealing structure. The large pressure difference of the medium is disassembled from the structure, so that the sealing and pressure-bearing functions of the valve core are separated, and the pressure difference distribution inside the valve core is changed. The large pressure difference is transferred from the main sealing structure to the sacrificial flap, so that the erosion effect of the high-speed medium only damages the sacrificial flap, so that the main sealing structure is well protected, thereby significantly improving the service life of the valve. When the sacrificial flap is damaged and fails, the valve can be disassembled online, the valve core is taken out, and a new sacrificial flap is replaced to complete the repair.

[0008] Preferably, the bottom of the main valve disc contacts the top of the valve seat to form the main sealing structure.

[0009] Preferably, the contact surface between the bottom of the main valve disc and the top of the valve seat is an inclined surface, and the main sealing structure formed is an inclined surface; the conical inclined surface is inclined inward from top to bottom.

[0010] Preferably, the outer side wall of the main valve disc contacts the inner side wall of the flow balancing sleeve to form the first auxiliary sealing structure, and the first auxiliary sealing structure is configured as a vertical cylindrical surface.

[0011] Preferably, the bottom of the sacrificial flap is arranged in the valve seat, and the throttling hole is opened at the bottom of the sacrificial flap; the conical surface of the outer wall of the sacrificial flap contacts the bottom conical surface of the valve seat to form the second auxiliary sealing structure, and the second auxiliary sealing structure is arranged above the throttling hole.

[0012] Preferably, the contact surface between the bottom outer wall of the sacrificial flap and the inner wall of the valve seat is set as a conical surface, and the cone angle of the conical surface faces downward.

[0013] Preferably, a locking nut is provided below the main valve disc, and the locking nut is sleeved outside the bottom of the valve stem; the sacrificial disc is sleeved outside the locking nut, and the spring is provided between the top surface of the main valve disc and the top surface of the sacrificial disc.

[0014] Preferably, the main valve flap is configured to be cylindrical, with a first through-hole on the top surface and an opening at the bottom end; the valve stem passes through the first through-hole; the bottom outer wall of the sacrificial flap is provided with a first annular step surface protruding outward, the main valve flap is sleeved outside the upper part of the sacrificial flap, and the bottom surface of the main valve flap is arranged above the first step surface.

[0015] Preferably, the sacrificial petal is configured to be cylindrical, with a second through hole on the top surface and an opening at the bottom end; the valve stem passes through the second through hole; the bottom outer wall of the locking nut is provided with a raised second step surface, and the top surface of the sacrificial petal is arranged above the second step surface.

[0016] Preferably, an annular first metal winding gasket is arranged between the valve body and the bottom of the valve seat, a packing ring is arranged between the top of the main valve disc and the valve stem, and an annular second metal winding gasket is arranged between the top of the valve body and the valve cover; a hollow bracket is connected to the top of the valve cover, and the top of the valve stem is arranged in the top of the bracket; a guide plate is arranged on the bracket, and a guide hole is provided on the guide plate, and the valve stem passes through the guide hole; an annular packing pad and an annular packing are arranged in sequence from bottom to top between the top inner wall of the valve cover and the outer wall of the valve stem; an annular packing sleeve and a packing pressure plate are arranged in sequence from bottom to top on the packing, and the packing pressure plate is connected to the top of the valve cover; a valve stem nut is sleeved on the top of the valve stem, a bearing is connected between the outer wall of the valve stem nut and the top inner wall of the bracket, and a bearing pressure cover is connected to the top of the bracket; an oil cup is installed on the side wall of the bracket at the bearing position.

[0017] The discharge valve of the present invention can achieve the following beneficial effects: The discharge valve provided by the present invention can solve the problem in the prior art that a higher strength welding material is needed for surfacing welding on the sealing surface, and the hardness of the sealing surface is increased to resist erosion by the medium, which leads to poor repairability of the damaged sealing surface, and the use of high-strength welding materials also increases the difficulty of surfacing welding and processing of the sealing surface. The discharge valve can effectively extend its service life without changing the strength and hardness of the surfacing material of the sealing surface, while having good repairability.

[0018] The discharge valve provided by the present invention has a sacrificial flap added below the main valve flap, and the sacrificial flap can be flexibly connected to the main valve flap through a spring and a locking nut. When the discharge valve is opened, the main valve flap opens first, and the sacrificial flap remains in place and blocks the flow of the medium; when the sealing surface of the main valve flap and the sealing surface of the valve seat are fully separated to form a sufficiently large circulation ring, the sacrificial flap begins to open and the medium begins to flow; at this time, the main valve flap has moved away from the micro-opening erosion zone, and the micro-opening erosion effect only damages the sacrificial flap, thereby effectively protecting the main valve flap. When the discharge valve is closed, the sacrificial flap closes first to block the flow of the medium, and then the main valve flap closes the sealing surface of the main valve flap in the state where there is no medium flow, effectively protecting the main valve flap from damage.

[0019] The discharge valve provided by the present invention cooperates with the main valve disc and the flow balancing sleeve to realize the flow balancing function, thereby preventing the medium from continuously impacting a specific position of the sealing surface due to unbalanced flow caused by the shape of the valve body flow channel or the disturbance of the valve internals, and making the medium flow at various positions of the sealing surface more balanced, which not only prolongs the service life of the sealing surface, but also helps to reduce vibration and noise.

[0020] The discharge valve provided by the present invention establishes a pressure-holding chamber between the inner wall of the flow-equalizing sleeve and the outer wall of the sacrificial valve sleeve, and the main sealing structure is located in the pressure-holding chamber and a primary auxiliary sealing structure is provided at the front and back. During the opening and closing process of the valve, the pressure difference before and after the main sealing structure is small, and the flow rate of the medium is slow, which effectively avoids the erosion effect of the medium on the main sealing structure and significantly improves the service life of the main sealing structure.

[0021] The discharge valve provided by the present invention can effectively extend the service life of the discharge valve without additionally increasing the hardness of the cladding material on the sealing surface of the discharge valve, and the effect is particularly obvious for the discharge valve working under high pressure difference and frequent opening and closing conditions.

[0022] The discharge valve provided by the present invention has a sacrificial flap which is used to bear almost all the pressure drop during large pressure difference discharge, and introduces the high-speed area of ​​the medium flow into the sleeve of the sacrificial flap. The erosion effect of the high-speed medium only damages the sacrificial flap. The porous sleeve structure of the sacrificial flap divides the medium into multiple thin streams when passing through the throttling hole of the sacrificial flap, which has a good vibration reduction and noise reduction effect.

[0023] The discharge valve provided by the present invention has a sacrificial flap and a main valve flap that can be flexibly connected by a spring and is easy to disassemble and replace. When the sacrificial flap is damaged and fails, the discharge valve can be disassembled online, the valve internals can be taken out, the locking nut and the sacrificial flap can be removed, and a new sacrificial flap can be quickly replaced. After reinstallation, the valve can be put into use again, and it has convenient repairability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 A schematic structural diagram of a discharge valve provided in one embodiment of the present invention.

[0025] Figure 2 A partial enlarged view of the sacrificial flap of the discharge valve before opening provided by one embodiment of the present invention.

[0026] Figure 3 A partial enlarged view of the sacrificial flap during the opening process of the discharge valve provided by one embodiment of the present invention.

[0027] Figure 4 A partial enlarged view of the sacrificial flap of the discharge valve after opening provided by one embodiment of the present invention.

[0028] In the figure, 1 is a valve body, 2 is a valve seat, 3 is a metal wound gasket, 4 is a sacrificial disc, 401 is a throttling hole, 402 is a first step surface, 5 is a main valve disc, 6 is a spring, 7 is a locking nut, 701 is a second step surface, 8 is a packing ring, 9 is a metal wound gasket, 10 is a valve cover, 11 is a packing pad, 12 is a packing, 13 is a packing sleeve, 14 is a packing pressure plate, 15 is a guide plate, 16 is a bracket, 17 is an oil cup, 18 is a bearing, 19 is a bearing cover, 20 is a valve stem, 21 is a valve stem nut, 22 is a flow equalizing sleeve, 221 is a flow equalizing hole, 231 is a main sealing structure, 232 is a first auxiliary sealing structure, and 233 is a second auxiliary sealing structure. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. 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 making creative work are within the scope of protection of the present invention.

[0030] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Example

[0031] Please refer to Figures 1 to 4 A discharge valve comprises a valve body 1, a valve seat 2, a valve cover 10, a valve stem 20, a main valve disc 5, a sacrificial disc 4 and a flow equalizing sleeve 22, wherein a cavity is arranged inside the valve body 1; the valve seat 2 is installed in the bottom of the valve body 1; the valve cover 10 is connected to the top of the valve body 1; the valve cover 10 has a stem hole; the valve stem 20 passes through the stem hole and is movably arranged in the cavity; the main valve disc 5 and the sacrificial disc 4 are both arranged in annular shapes and are movably arranged in the cavity; the sacrificial disc 4 is sleeved outside the bottom of the valve stem 20, the main valve disc 5 is sleeved outside the upper part of the sacrificial disc 4, and a spring 6 is arranged between the main valve disc 5 and the sacrificial disc 4; a throttle hole 401 is arranged on the lower side wall of the sacrificial disc 4; the flow equalizing sleeve 22 is arranged in the cavity; the flow equalizing sleeve 22 is sleeved on the main valve disc 5, a flow balancing hole 221 is provided on the side wall of the flow balancing sleeve 22, and the total area of ​​the flow balancing hole 221 is larger than the total area of ​​the throttling hole 401; a pressure holding chamber 23 is arranged between the inner wall of the flow balancing sleeve 22 and the outer wall of the sacrificial flap 4, and a main sealing structure 231, a first auxiliary sealing structure 232 and a second auxiliary sealing structure 233 are arranged in the pressure holding chamber 23; the first auxiliary sealing structure 232 and the second auxiliary sealing structure 233 are respectively arranged on both sides of the main sealing structure 231; the main sealing structure 231 is formed by the contact between the main valve flap 5 and the valve seat 2, the first auxiliary sealing structure 232 is formed by the contact between the main valve flap 5 and the flow balancing sleeve 22, and the second auxiliary sealing structure 233 is formed by the contact between the sacrificial flap 4 and the valve seat 2.

[0032] The discharge valve of this embodiment opens the main valve flap 5 as shown in FIG. Figures 2 to 3 As shown, the working principle of the sealing surface protection of the main valve disc 5 is as follows: like Figure 2 As shown, when the discharge valve is in the closed state, the main valve flap 5 and the sacrificial flap 4 are both completely closed, and the spring 6 is compressed to the shortest.

[0033] like Figure 3 As shown, when the discharge valve needs to be opened, the valve stem 20 moves upward, driving the main valve disc 5 to move upward, the spring 6 gradually stretches, and the main valve disc 5 is out of contact with the valve seat 2, that is, the main sealing structure 231 is opened; at the same time, the flow balancing hole 221 on the flow balancing sleeve 22 is blocked by the outer wall of the main valve disc 5, that is, the first auxiliary sealing structure 232 is maintained, and at this time, the medium only forms a gap flow between the flow balancing sleeve 22 and the main valve disc 5, and the medium flow rate at the position of the opened main sealing structure 231 is slow; Until Figure 4 As shown in FIG. 2 , as the main valve flap 5 continues to move upward, the first auxiliary sealing structure 232 opens; as the spring 6 gradually stretches to its longest length, the main valve flap 5 and the sacrificial flap 4 become one under the tightening action of the spring 6, and the two begin to move upward synchronously driven by the valve stem 20, so that the sacrificial flap 4 is out of contact with the valve seat 2, that is, the second auxiliary sealing structure 233 opens, and then the throttle hole 401 at the lower part of the sacrificial flap 4 and the flow balancing hole 221 of the flow balancing sleeve 22 are opened, until the second auxiliary sealing structure 233 is fully opened; in this process, the medium enters the inner wall of the flow balancing sleeve 22 and the sacrificial flap 4, and the sacrificial flap 4 is opened. In the pressure-holding chamber 23 formed between the outer walls of the sacrificial flap 4, since the total area of ​​the equalizing holes 221 is larger than the total area of ​​the throttling holes 401, the medium pressure drop is almost entirely concentrated on the sacrificial flap 4, which produces two beneficial effects: on the one hand, the medium flow rate V1 in the pressure-holding chamber 23 is limited within an acceptable range, so that the medium escapes from the main sealing structure 231 at a low speed, greatly weakening the erosion effect of the medium on the main sealing structure 231; on the other hand, when the medium passes through the throttling holes 401 of the sacrificial flap 4, it is divided into multiple thin streams, which has a good vibration reduction and noise reduction effect. The medium flow rate V2 in the sacrificial flap 4 is much larger than the flow rate V1 in the pressure-holding chamber 23, so that the erosion effect of the medium is concentrated on the throttling holes 401 and the inner wall of the sacrificial flap 4, thereby effectively protecting the main sealing structure 231. Figure 4 The arrow in the middle shows the medium flow direction.

[0034] Similarly, when the discharge valve is closed, the main valve flap 5 and the sacrificial flap 4 move downward synchronously, the throttle hole 401 of the sacrificial flap 4 is gradually hidden under the valve seat 2, and the second auxiliary sealing structure 233 begins to close until the sacrificial flap 4 contacts the valve seat 2, the sacrificial flap 4 stops moving downward, and the second auxiliary sealing structure 233 is completely closed. At this time, the equalizing hole 221 of the equalizing sleeve 22 is completely blocked by the outer wall of the main valve flap 5, the first auxiliary sealing structure 232 is closed, and only the gap flow remains in the pressure holding chamber 23, and the medium flow rate at the main sealing structure 231 is slow; then, the main valve flap 5 continues to move downward, the spring 6 is compressed, until the main sealing structure 231 is closed, and the discharge valve is completely closed.

[0035] It can be seen that the discharge valve provided in this embodiment structurally changes the pressure difference distribution inside the valve core, and transfers the large pressure difference from the main sealing structure 231 to the sacrificial flap 4, so that the erosion of the high-speed medium only damages the sacrificial flap 4, and the main sealing structure 231 is well protected, thereby significantly improving the service life of the valve. When the sacrificial flap 4 is damaged and fails, the discharge valve can be disassembled online, the valve core is removed, and a new sacrificial flap 4 is replaced to complete the repair.

[0036] The valve stem 20 is movably arranged in the cavity, that is, the valve stem 20 can be lifted and moved in the cavity. The main valve flap 5 and the sacrificial flap 4 are both movably arranged in the valve seat 2 and the cavity, that is, the main valve flap 5 and the sacrificial flap 4 can be lifted and moved in the valve seat 2 and the cavity. The sacrificial flap 4 is movably arranged below the main valve flap 5, and the main valve flap 5 and the sacrificial flap 4 can be lifted and moved relative to each other. The throttling hole 401 and the flow balancing hole 221 are both set to at least two, evenly distributed, and can be set to circular through holes.

[0037] Specifically, the bottom of the main valve disc 5 contacts the top of the valve seat 2 to form a main sealing structure 231 .

[0038] For example, the contact surface between the bottom of the main valve flap 5 and the top of the valve seat 2 is an inclined surface, and the formed main sealing structure 231 is an inclined surface; the conical inclined surface is inclined inward from top to bottom.

[0039] Specifically, the outer wall of the main valve disc 5 contacts the inner wall of the flow balancing sleeve 22 to form a first auxiliary sealing structure 232 . The first auxiliary sealing structure 232 is configured as a vertical cylindrical surface.

[0040] Specifically, the bottom of the sacrificial flap 4 is arranged in the valve seat 2, and the throttling hole 401 is opened at the bottom of the sacrificial flap 4; the conical surface of the outer wall of the sacrificial flap 4 contacts the bottom conical surface of the valve seat 2 to form a second auxiliary sealing structure 233, and the second auxiliary sealing structure 233 is arranged above the throttling hole 401.

[0041] For example, the contact surface between the bottom outer wall of the sacrificial flap 4 and the inner wall of the valve seat 2 is set to be a conical surface, and the cone angle of the conical surface faces downward.

[0042] It can be seen that the valve seat 2 can be provided with two conical surfaces, the first conical surface is provided at the top of the valve seat 2, and the conical surface matches and contacts with the conical surface at the bottom of the main valve disc 5 to form a main sealing structure 231; the second conical surface is provided on the bottom inner wall of the valve seat 2, and the conical surface contacts with the conical surface of the outer wall of the sacrificial disc 4 to form a second auxiliary sealing structure 233.

[0043] In some embodiments, a locking nut 7 is provided below the main valve flap 5, and the locking nut 7 is sleeved on the outside of the bottom of the valve stem 20; the sacrificial flap 4 is sleeved on the outside of the locking nut 7, and the spring 6 is provided between the top surface of the main valve flap 5 and the top surface of the sacrificial flap 4.

[0044] When the sacrificial flap 4 is damaged, the discharge valve can be disassembled online, the valve internals can be taken out, the locking nut 7 and the sacrificial flap 4 can be removed and replaced, and the discharge valve can be put into use again after reinstallation.

[0045] The locking nut 7 is sleeved and connected to the outside of the bottom of the valve stem 20. For example, an external thread is arranged outside the bottom of the valve stem 20, and the locking nut 7 is screwed to the bottom of the valve stem 20. The top surface of the main valve flap 5 can be fixedly connected to the top of the locking nut 7. The sacrificial flap 4 can be movably sleeved outside the locking nut 7, and the two can be lifted and moved relative to each other.

[0046] Specifically, the main valve flap 5 is set to be cylindrical, with a first through hole on the top surface and an opening at the bottom end; the valve stem 20 passes through the first through hole; the bottom outer wall of the sacrificial flap 4 is provided with a first annular step surface 402 protruding outward, the main valve flap 5 is sleeved outside the upper part of the sacrificial flap 4, and the bottom surface of the main valve flap 5 is arranged above the first step surface 402.

[0047] The spring 6 is arranged between the top surface of the main valve flap 5 and the top surface of the sacrificial flap 4. The top end and the bottom end of the spring 6 can be connected to the top surface of the main valve flap 5 and the top surface of the sacrificial flap 4 respectively.

[0048] In some embodiments, the sacrificial petal 4 is configured to be cylindrical, with a second through-hole on the top surface and an opening at the bottom end; the valve stem 20 passes through the second through-hole; the bottom outer wall of the locking nut 7 is provided with a raised second step surface 701, and the top surface of the sacrificial petal 4 is provided above the second step surface 701.

[0049] The top surface of the sacrificial petal 4 forms a shoulder of the sacrificial petal 4, and the second step surface 701 of the locking nut 7 forms a shoulder of the locking nut 7. Figure 4 As shown, as the valve stem 20 gradually moves upward, the spring 6 gradually stretches to its longest length until the shoulder of the locking nut 7 contacts the shoulder of the sacrificial flap 4. The main valve flap 5 and the sacrificial flap 4 become one under the tightening action of the spring 6, and the two begin to move upward synchronously driven by the valve stem 20.

[0050] When the valve is closed, the main valve flap 5 moves down together with the sacrificial flap 4, and the throttle hole 401 of the sacrificial flap 4 is gradually hidden under the valve seat 2, until the bottom of the sacrificial flap 4 contacts the top of the valve seat 2 to form a conical contact surface, that is, the conical second auxiliary sealing structure 233 is closed. At this time, the equalizing hole 221 of the flow equalizing sleeve 22 is completely blocked by the outer wall of the main valve flap 5, the first auxiliary sealing structure 231 is closed, and only the gap flow remains in the pressure holding chamber 23, and the medium flow rate at the main sealing structure 231 is slow; then, the main valve flap 5 continues to move down, the shoulder of the locking nut 7 is separated from the shoulder of the sacrificial flap 4, and the spring 6 is compressed until the main sealing structure is closed and the valve is fully closed.

[0051] Specifically, an annular first metal wound gasket 3 is arranged between the valve body 1 and the bottom of the valve seat 2, a packing ring 8 is arranged between the top of the main valve disc 5 and the valve stem 20, and an annular second metal wound gasket 9 is arranged between the top of the valve body 1 and the valve cover 10; A hollow bracket 16 is connected to the top of the valve cover 10, and the top of the valve stem 20 is arranged inside the top 16 of the bracket; The bracket 16 is provided with a guide plate 15, the guide plate 15 is provided with a guide hole, and the valve stem 20 passes through the guide hole; An annular packing pad 11 and an annular packing 12 are sequentially arranged between the top inner wall of the valve cover 10 and the outer wall of the valve stem 20 from bottom to top; an annular packing gland 13 and a packing pressure plate 14 are sequentially arranged on the packing 12 from bottom to top, and the packing pressure plate 14 is connected to the top of the valve cover 10; A valve stem nut 21 is sleeved on the top of the valve stem 20, a bearing 18 is connected between the outer wall of the valve stem nut 21 and the top inner wall of the bracket 16, and a bearing gland 19 is connected to the top of the bracket 16; an oil cup 17 is installed on the side wall of the bracket 16 at the position of the bearing 18.

[0052] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A discharge valve, characterized in that: include: A valve body having a cavity disposed therein; a valve seat, mounted in the bottom of the valve body; A valve cover is connected to the top of the valve body; the valve cover is provided with a stem hole; a valve stem passing through the stem hole and movably disposed in the cavity; The main valve flap and the sacrificial flap are both annular and movably arranged in the cavity; the sacrificial flap is sleeved outside the bottom of the valve stem, and the main valve flap is sleeved outside the upper part of the sacrificial flap, and a spring is arranged between the main valve flap and the sacrificial flap; a throttling hole is arranged on the lower side wall of the sacrificial flap; A flow balancing sleeve is arranged in the cavity; the flow balancing sleeve is arranged outside the main valve disc, and a flow balancing hole is provided on the side wall of the flow balancing sleeve, and the total area of ​​the flow balancing hole is greater than the total area of ​​the throttling hole; A pressure-holding cavity is arranged between the inner wall of the flow-balancing sleeve and the outer wall of the sacrificial flap, and a main sealing structure, a first auxiliary sealing structure and a second auxiliary sealing structure are arranged in the pressure-holding cavity; the first auxiliary sealing structure and the second auxiliary sealing structure are arranged on both sides of the main sealing structure, respectively; the main sealing structure is formed by the contact between the main valve flap and the valve seat, the first auxiliary sealing structure is formed by the contact between the main valve flap and the flow-balancing sleeve, and the second auxiliary sealing structure is formed by the contact between the sacrificial flap and the valve seat.

2. The discharge valve according to claim 1, characterized in that The bottom of the main valve disc contacts the top of the valve seat to form the main sealing structure.

3. The discharge valve according to claim 2, characterized in that The contact surface between the bottom of the main valve disc and the top of the valve seat is an inclined surface, and the main sealing structure formed is an inclined surface; the conical inclined surface is inclined inward from top to bottom.

4. The discharge valve according to claim 1, characterized in that The outer side wall of the main valve disc contacts the inner side wall of the flow balancing sleeve to form the first auxiliary sealing structure, and the first auxiliary sealing structure is configured as a vertical cylindrical surface.

5. The discharge valve according to claim 1, characterized in that The bottom of the sacrificial flap is arranged in the valve seat, and the throttling hole is opened at the bottom of the sacrificial flap; the conical surface of the outer wall of the sacrificial flap contacts the bottom conical surface of the valve seat to form the second auxiliary sealing structure, and the second auxiliary sealing structure is arranged above the throttling hole.

6. The discharge valve according to claim 5, characterized in that The contact surface between the bottom outer wall of the sacrificial flap and the inner wall of the valve seat is set as a conical surface, and the cone angle of the conical surface faces downward.

7. The discharge valve according to claim 1, characterized in that A locking nut is arranged below the main valve disc, and the locking nut is sleeved outside the bottom of the valve stem; the sacrificial disc is sleeved outside the locking nut, and the spring is arranged between the top surface of the main valve disc and the top surface of the sacrificial disc.

8. The discharge valve according to claim 7, characterized in that The main valve flap is set to be cylindrical, with a first through hole on the top surface and an opening at the bottom end; the valve stem passes through the first through hole; the bottom outer wall of the sacrificial flap is provided with a first annular step surface protruding outward, the main valve flap is sleeved outside the upper part of the sacrificial flap, and the bottom surface of the main valve flap is arranged above the first step surface.

9. The discharge valve according to claim 8, characterized in that The sacrificial flap is set in a cylindrical shape, with a second through hole on the top surface and an opening at the bottom end; the valve stem passes through the second through hole; the bottom outer wall of the locking nut is provided with a raised second step surface, and the top surface of the sacrificial flap is arranged above the second step surface.

10. The discharge valve according to any one of claims 1 to 9, characterized in that: A first annular metal wound gasket is arranged between the valve body and the bottom of the valve seat, a packing ring is arranged between the top of the main valve disc and the valve stem, and a second annular metal wound gasket is arranged between the top of the valve body and the valve cover; A hollow bracket is connected to the upper side of the valve cover, and the top of the valve stem is arranged inside the top of the bracket; The bracket is provided with a guide plate, the guide plate is provided with a guide hole, and the valve stem passes through the guide hole; An annular packing pad and an annular packing are arranged in sequence from bottom to top between the top inner wall of the valve cover and the outer wall of the valve stem; an annular packing gland and a packing pressure plate are arranged in sequence from bottom to top on the packing, and the packing pressure plate is connected to the top of the valve cover; The top sleeve of the valve stem is connected with a valve stem nut, a bearing is connected between the outer wall of the valve stem nut and the top inner wall of the bracket, and a bearing gland is connected to the top of the bracket; an oil cup is installed on the side wall of the bracket at the bearing position.

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