A drain valve

Abstract

The present application belongs to the technical field of valve, and discloses a discharge valve, which comprises a valve body, a valve seat, a valve cover, a valve rod, a main valve flap, a sacrifice flap and a uniform flow sleeve, the sacrifice flap is sleeved outside the bottom of the valve rod, the main valve flap is sleeved outside the upper part of the sacrifice flap, and a spring is arranged between the main valve flap and the sacrifice flap; a throttle hole is formed in the lower side wall of the sacrifice flap; the uniform flow sleeve is sleeved outside the main valve flap, a uniform flow hole is formed in the side wall of the uniform flow sleeve, and the total area of the uniform flow hole is greater than that of the throttle hole; a pressure holding cavity is arranged between the inner wall of the uniform flow sleeve and the outer wall of the sacrifice 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 present application effectively prolongs the service life of the discharge valve without changing the strength and hardness of the sealing surface surfacing material, and has good repairability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of valves, and relates to a discharge valve. BACKGROUND

[0002] In the production process of the power, metallurgy, petroleum, chemical industry and other industries, large pressure difference discharge of steam, saturated water or other working medium is a common working condition, and the corresponding pressure difference of these working conditions is above 10 MPa. At present, the valve used for large pressure difference discharge working condition usually uses a stop valve. The stop valve is a common type of valve, which has the characteristics of simple structure, reliable sealing, flexible operation and small stroke. Its working principle is that the valve stem is driven to move up and down by a hand wheel or an electric device, and the valve disc is driven by the valve stem to separate or press the valve seat to realize the opening or closing of the valve.

[0003] The sealing performance of the stop valve is good, and it is usually used as a shut-off valve. According to its working condition, it can be divided into a normally open type, a normally closed type and a frequent opening and closing type. The valve disc of the normally open type stop valve is always in the fully open position, and the valve disc sealing surface is far away from the valve seat sealing surface. The medium flows through the valve seat at a normal flow rate, and the erosion of the sealing surface is weak, so the service life of the valve is long. The sealing surface of the normally closed type stop valve is always in close contact, and there is no medium flow between the valve disc sealing surface and the valve seat sealing surface. The sealing surface is not eroded by the medium at all, so the valve is not easy to be damaged. However, in the application scene of large pressure difference discharge, such as the blow cleaner of the thermal power boiler, the regular blowdown and the air discharge pipeline system, the valve needs to be frequently opened and closed and accompanied by large pressure difference operation. When the valve is opened, the valve disc and the valve seat gradually separate, and the medium flows through the flow-through annular belt between the two sealing surfaces. In the initial stage of opening, the cross-sectional area of the flow-through annular belt is extremely small, and the large pressure difference is concentrated in front of and behind the sealing surface. Under the action of the large pressure difference, the medium generates a very high flow rate, which not only causes serious erosion of the sealing surface, but also causes vibration of the pipeline and generates a lot of noise. Conversely, when the discharge is over and the valve is closed, the valve disc gradually approaches the valve seat, and the pressure difference is again concentrated in front of and behind the sealing surface, causing erosion of the sealing surface and accompanied by vibration and noise. Under this working condition, the valve is extremely easy to be damaged, and in the extreme case, some valves even appear leakage after several opening and closing. As can be seen, under the condition of large pressure difference discharge, when the valve is in the micro-opening position, a narrow flow-through annular belt is formed between the sealing surfaces, which throttles the medium, and the pressure difference is concentrated in front of and behind the sealing surface, resulting in a too high flow rate of the medium at the sealing surface, which is the fundamental reason for the damage of the valve sealing surface.

[0004] The existing technical solution mainly starts from the material, and the sealing surface is welded with higher strength welding material to increase the hardness of the sealing surface to resist the erosion of the medium. This scheme can indeed prolong the service life of the sealing surface to a certain extent, but it does not solve the problem of the concentration of the pressure difference in the sealing surface when the valve is micro-opened, and the repairability of the damaged sealing surface is poor. In addition, the use of high-strength welding material also increases the difficulty of sealing surface welding and processing, so the effect is still not ideal. SUMMARY

[0005] The present application provides a kind of discharge valve, to solve the problem that higher strength welding material needs to be welded to sealing surface in prior art, by improving the hardness of sealing surface to resist the erosion of medium, so that the repairability of sealing surface damage is poor, the use of high-strength welding material also increases the difficulty of sealing surface welding and processing;It is realized without changing the strength and hardness of sealing surface welding material, effectively prolong the service life of discharge valve, while having good repairability.

[0006] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0007] The present application provides a kind of discharge valve, including valve body, valve seat, valve cover, valve stem, main valve, sacrifice petal and flow uniformity sleeve, the inside of the valve body is provided with cavity;The valve seat is installed in the bottom of the valve body;The valve cover is connected at the top of the valve body;The valve cover is set up stem hole;The valve stem passes through the stem hole, and is movably arranged in the cavity;The main valve and the sacrifice petal are both arranged as annular, and are movably arranged in the cavity;The sacrifice petal is sleeved on the bottom of the valve stem, the main valve is sleeved on the upper part of the sacrifice petal, and the spring is arranged between the main valve and the sacrifice petal;The lower part of the side wall of the sacrifice petal is set up throttle hole;The flow uniformity sleeve is arranged in the cavity;The flow uniformity sleeve is sleeved on the outside of the main valve, the side wall of the flow uniformity sleeve is set up flow uniformity hole, and the total area of the flow uniformity hole is greater than the total area of the throttle hole;The inner wall of the flow uniformity sleeve and the outer wall of the sacrifice petal are arranged between the pressure holding chamber, the main sealing structure, the first auxiliary sealing structure and the 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 the two sides of the main sealing structure;The main sealing structure is formed by the main valve and the valve seat being in contact, the first auxiliary sealing structure is formed by the main valve and the flow uniformity sleeve being in contact, and the second auxiliary sealing structure is formed by the sacrifice petal and the valve seat being in contact.

[0008] The application provides a discharge valve, which is characterized in that a flow equalizing sleeve is arranged in the valve body, a sacrifice valve with a sleeve structure is additionally arranged at the lower part of the main valve disc, a pressure holding cavity is formed between the inner side wall of the flow equalizing sleeve and the outer side wall of the sleeve structure of the sacrifice valve, the main sealing structure is arranged in the pressure holding cavity, and one level of auxiliary sealing structure is arranged in front of and behind the main sealing structure.

[0009] Preferably, the bottom of the main valve disc is in contact with the top of the valve seat to form the main sealing structure.

[0010] Preferably, the contact surface between the bottom of the main valve disc and the top of the valve seat is a slope, and the main sealing structure formed by the contact surface is a slope; the slope is inclined inward from top to bottom.

[0011] Preferably, the outer side wall of the main valve disc is in contact with the inner side wall of the flow equalizing sleeve to form the first auxiliary sealing structure, and the first auxiliary sealing structure is arranged as a vertical cylindrical surface.

[0012] Preferably, the bottom of the sacrifice valve is arranged in the valve seat, the throttling hole is arranged in the bottom of the sacrifice valve, the outer side wall of the sacrifice valve is in contact with the bottom of the valve seat to form the second auxiliary sealing structure, and the second auxiliary sealing structure is arranged above the throttling hole.

[0013] Preferably, the contact surface between the bottom of the sacrifice valve and the inner side wall of the valve seat is arranged as a conical surface, and the taper angle of the conical surface is downward.

[0014] Preferably, a locking nut is arranged below the main valve disc, the locking nut is arranged outside the bottom of the valve rod, the sacrifice valve is arranged outside the locking nut, and the spring is arranged between the top surface of the main valve disc and the top surface of the sacrifice valve.

[0015] Preferably, the main valve disc is arranged as a cylindrical structure, the first through hole is arranged in the top surface of the main valve disc, and the bottom end is open; the valve rod passes through the first through hole; the bottom outer wall of the sacrifice valve is arranged as an outwardly protruding annular first step surface, the main valve disc is arranged outside the upper part of the sacrifice valve, and the bottom surface of the main valve disc is arranged above the first step surface.

[0016] Preferably, the sacrifice valve is provided in a cylindrical shape, the top surface of which is provided with a second through hole, and the bottom end of which is open; the valve rod passes through the second through hole; the bottom outer wall of the locking nut is provided with a second stepped surface, and the top surface of the sacrifice valve is arranged above the second stepped surface.

[0017] Preferably, an annular first metal winding pad 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 rod, and an annular second metal winding pad is arranged between the top of the valve body and the valve cover; a hollow support is connected to the top surface of the valve cover, and the top of the valve rod is arranged in the top of the support; the support is provided with a guide plate, the guide plate is provided with a guide hole, and the valve rod passes through the guide hole; an annular packing pad and an annular packing are arranged between the top inner wall of the valve cover and the outer wall of the valve rod from bottom to top; an annular packing sleeve and a packing pressing plate are arranged on the top surface of the packing from bottom to top, and the packing pressing plate is connected to the top of the valve cover; a valve rod nut is connected to the top of the valve rod, a bearing is connected between the outer wall of the valve rod nut and the top inner wall of the support, and a bearing pressing cover is connected to the top of the support; an oil cup is mounted on the side wall of the support at the position of the bearing.

[0018] The discharge valve provided by the application can achieve the following beneficial effects:

[0019] The discharge valve provided by the application can solve the problem that in the prior art, a higher-strength welding material needs to be used for sealing surface overlay welding, the hardness of the sealing surface is increased to resist the erosion of the medium, and thus the repairability of the sealing surface after damage is poor, and the use of the high-strength welding material increases the difficulty of sealing surface overlay welding and processing; the service life of the discharge valve is effectively prolonged without changing the strength and hardness of the sealing surface overlay welding material, and the discharge valve has good repairability.

[0020] The discharge valve provided by the application is provided with a sacrifice valve below the main valve disc, and the sacrifice valve is flexibly connected to the main valve disc through a spring and a locking nut. When the discharge valve is opened, the main valve disc is opened first, and the sacrifice valve remains in place and blocks the flow of the medium; when the sealing surface of the main valve disc and the sealing surface of the valve seat are fully separated to form a large enough flow-through annular zone, the sacrifice valve starts to open, and the medium starts to flow; at this time, the main valve disc is far away from the micro-opening erosion zone, and the micro-opening erosion effect only causes damage to the sacrifice valve, thereby effectively protecting the main valve disc. When the discharge valve is closed, the sacrifice valve is closed first to block the flow of the medium, and then the sealing surface of the main valve disc is closed in the state that the medium does not flow, thereby effectively protecting the main valve disc from being damaged.

[0021] The discharge valve provided by the application is matched with the main valve disc and the flow equalizing sleeve to realize the flow equalizing function, avoid the continuous impact on the sealing surface caused by the unbalanced flow of the medium due to the flow channel shape of the valve body or the disturbance of the valve inner part, make the medium flow of each position of the sealing surface more balanced, prolong the service life of the sealing surface, and be beneficial to vibration reduction and noise reduction.

[0022] The discharge valve provided by the application establishes the pressure holding cavity between the inner wall of the flow equalizing sleeve and the outer wall of the sacrifice disc sleeve, the main sealing structure is located in the pressure holding cavity and is provided with one level of auxiliary sealing structure in front and back, the pressure difference in front and back of the main sealing structure is small during the opening and closing process of the valve, the medium flow rate is slow, the erosion effect of the medium on the main sealing structure is effectively avoided, and the service life of the main sealing structure is significantly improved.

[0023] The discharge valve provided by the application does not need to additionally increase the hardness of the sealing surface of the discharge valve, can effectively prolong the service life of the discharge valve, and the effect is particularly obvious for the discharge valve working under the condition of high pressure difference and frequent opening and closing.

[0024] The sacrifice disc of the discharge valve is used for bearing almost all pressure drops during the discharge under a large pressure difference, the high-speed area of the medium flow is introduced into the sleeve of the sacrifice disc, and the erosion effect of the high-speed medium only causes damage to the sacrifice disc; the porous sleeve structure of the sacrifice disc divides the medium into multiple streams when the medium passes through the throttle hole of the sacrifice disc, and has good vibration reduction and noise reduction effects.

[0025] The sacrifice disc and the main valve disc of the discharge valve can be flexibly connected through a spring and are easy to disassemble and replace; when the sacrifice disc is damaged and fails, the discharge valve can be disassembled online, the valve inner part is taken out, the locking nut and the sacrifice disc are disassembled, a new sacrifice disc can be quickly replaced, and the valve can be put into use again after reinstallation, and the discharge valve has convenient repairability. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings, which are included to provide a further understanding of the application and constitute a part of this application, illustrate certain illustrative embodiments of the application and together with their description serve to explain the application. In the drawings:

[0027] Figure 1 The structural schematic view of the discharge valve provided by an embodiment of the application.

[0028] Figure 2 The partial enlarged view of the sacrifice disc before opening of the discharge valve provided by an embodiment of the application.

[0029] Figure 3 The partial enlarged view of the sacrifice disc in the opening process of the discharge valve provided by an embodiment of the application.

[0030] Figure 4A partial enlarged view of the local area of the sacrifice valve after the opening of the discharge valve according to an embodiment of the present application.

[0031] In the figure, 1 is a valve body, 2 is a valve seat, 3 is a metal winding pad, 4 is a sacrifice valve, 401 is a throttle hole, 402 is a first step surface, 5 is a main valve, 6 is a spring, 7 is a lock nut, 701 is a second step surface, 8 is a packing ring, 9 is a metal winding pad, 10 is a valve cover, 11 is a packing pad, 12 is packing, 13 is a packing sleeve, 14 is a packing 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

[0032] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described below in conjunction with specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0033] The technical solutions provided by the embodiments of the present application will be described in detail below in conjunction with the drawings. EMBODIMENT

[0034] Please refer to Figures 1 to 4A discharge valve includes 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 equalization sleeve 22. The valve body 1 has an internal cavity. The valve seat 2 is installed at 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 rod hole. The valve stem 20 passes through the rod hole and is movably disposed within the cavity. The main valve disc 5 and the sacrificial disc 4 are both annular and movably disposed within the cavity. The sacrificial disc 4 is sleeved outside the bottom of the valve stem 20, and the main valve disc 5 is sleeved outside the upper part of the sacrificial disc 4. A spring 6 is disposed between the main valve disc 5 and the sacrificial disc 4. A throttling orifice 401 is formed on the lower side wall of the sacrificial disc 4. The flow equalization sleeve 22 is disposed within the cavity and is sleeved on the main valve disc. Outside of 5, the side wall of the flow equalization sleeve 22 is provided with flow equalization holes 221, and the total area of ​​the flow equalization holes 221 is larger than the total area of ​​the throttling holes 401; a pressure-holding cavity 23 is provided between the inner wall of the flow equalization sleeve 22 and the outer wall of the sacrificial petal 4, and a main sealing structure 231, a first auxiliary sealing structure 232 and a second auxiliary sealing structure 233 are provided in the pressure-holding cavity 23; the first auxiliary sealing structure 232 and the second auxiliary sealing structure 233 are respectively provided on both sides of the main sealing structure 231; the main sealing structure 231 is formed by the contact between the main valve disc 5 and the valve seat 2, the first auxiliary sealing structure 232 is formed by the contact between the main valve disc 5 and the flow equalization sleeve 22, and the second auxiliary sealing structure 233 is formed by the contact between the sacrificial petal 4 and the valve seat 2.

[0035] In this embodiment, the main valve disc 5 of the discharge valve opens as follows: Figures 2 to 3 As shown, the working principle of the sealing surface protection of the main valve disc 5 is as follows:

[0036] like Figure 2 As shown, when the discharge valve is in the closed state, both the main valve disc 5 and the sacrificial disc 4 are fully closed, and the spring 6 is compressed to its shortest length.

[0037] like Figure 3 As shown, when the discharge valve needs to be opened, the valve stem 20 moves upward, causing the main valve disc 5 to move upward, the spring 6 gradually extends, and the main valve disc 5 disengages from the valve seat 2, that is, the main sealing structure 231 is opened; at the same time, the flow equalization hole 221 on the flow equalization 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 equalization 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.

[0038] Until Figure 4As shown, as the main valve disc 5 continues to move upward, the first auxiliary sealing structure 232 opens; as the spring 6 gradually extends to the longest, the main valve disc 5 and the sacrifice disc 4 become an integral whole under the tension of the spring 6, and both begin to move upward synchronously under the driving of the valve rod 20, so that the sacrifice disc 4 is separated from 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 sacrifice disc 4 and the flow equalization hole 221 of the flow equalization sleeve 22 open, until the second auxiliary sealing structure 233 is fully opened; in this process, the medium enters the pressure accumulation cavity 23 formed between the inner side wall of the flow equalization sleeve 22 and the outer side wall of the sacrifice disc 4, and since the total area of the flow equalization hole 221 is greater than the total area of the throttle hole 401, the medium pressure drop is almost entirely concentrated on the sacrifice disc 4, which produces two beneficial effects: on the one hand, the medium flow rate V1 at the pressure accumulation cavity 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 of the medium on the main sealing structure 231; on the other hand, the medium is divided into multiple streams when passing through the throttle hole 401 of the sacrifice disc 4, having a good vibration and noise reduction effect. The medium flow rate V2 in the sacrifice disc 4 is much greater than the flow rate V1 in the pressure accumulation cavity 23, so that the erosion of the medium is concentrated on the throttle hole 401 and the inner side wall of the sacrifice disc 4, thereby effectively protecting the main sealing structure 231. Figure 4 The arrow indicates the direction of the medium flow.

[0039] Similarly, when the discharge valve is closed, the main valve disc 5 moves downward synchronously with the sacrifice disc 4, the throttle hole 401 of the sacrifice disc 4 gradually hides under the valve seat 2, the second auxiliary sealing structure 233 begins to close, until the sacrifice disc 4 contacts the valve seat 2 and stops moving downward, and the second auxiliary sealing structure 233 is fully closed. At this time, the flow equalization hole 221 of the flow equalization sleeve 22 is fully blocked by the outer side wall of the main valve disc 5, the first auxiliary sealing structure 232 is closed, and only a gap flow exists in the pressure accumulation cavity 23, and the medium flow rate at the main sealing structure 231 is slow; then, the main valve disc 5 continues to move downward, the spring 6 is compressed, until the main sealing structure 231 is closed, and the discharge valve is fully closed.

[0040] It can be seen that the discharge valve provided by the embodiment changes the pressure difference distribution inside the valve core in structure, transfers the large pressure difference from the main sealing structure 231 to the sacrifice disc 4, so that the erosion of the high-speed medium only causes damage to the sacrifice disc 4, and the main sealing structure 231 is well protected, thereby significantly improving the service life of the valve. When the sacrifice disc 4 is damaged and fails, the discharge valve can be disassembled online, the valve core can be taken out, and a new sacrifice disc 4 can be replaced, so that the repair can be completed.

[0041] The valve rod 20 is movably arranged in the cavity, that is, the valve rod 20 can move up and down in the cavity. The main valve disc 5 and the sacrifice disc 4 are movably arranged in the valve seat 2 and the cavity, that is, the main valve disc 5 and the sacrifice disc 4 can move up and down in the valve seat 2 and the cavity. The sacrifice disc 4 is movably arranged below the main valve disc 5, and the main valve disc 5 and the sacrifice disc 4 can move up and down relative to each other. The throttling holes 401 and the flow equalizing holes 221 are both arranged as at least two and uniformly distributed, and can be circular through holes.

[0042] Specifically, the bottom of the main valve disc 5 is in contact with the top of the valve seat 2 to form a main sealing structure 231.

[0043] For example, the contact surface between the bottom of the main valve disc 5 and the top of the valve seat 2 is a bevel, and the main sealing structure 231 formed thereby is a bevel; the bevel is inclined inward from top to bottom.

[0044] Specifically, the outer side wall of the main valve disc 5 is in contact with the inner side wall of the flow equalizing sleeve 22 to form a first auxiliary sealing structure 232, and the first auxiliary sealing structure 232 is arranged as a vertical cylindrical surface.

[0045] Specifically, the bottom of the sacrifice disc 4 is arranged in the valve seat 2, and the throttling holes 401 are arranged in the bottom of the sacrifice disc 4. The outer side wall conical surface of the sacrifice disc 4 is in contact with 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 holes 401.

[0046] For example, the contact surface between the bottom outer side wall of the sacrifice disc 4 and the inner side wall of the valve seat 2 is arranged as a conical surface, and the conical surface is downwardly tapered.

[0047] It can be seen that the valve seat 2 can be provided with two conical surfaces. The first conical surface is arranged on the top of the valve seat 2, and the conical surface is matched with the conical surface of the bottom of the main valve disc 5 to form the main sealing structure 231. The second conical surface is arranged on the inner side wall of the bottom of the valve seat 2, and the conical surface is in contact with the outer side wall conical surface of the sacrifice disc 4 to form the second auxiliary sealing structure 233.

[0048] In some embodiments, the lock nut 7 is arranged below the main valve disc 5 and is sleeved on the bottom of the valve rod 20. The sacrifice disc 4 is sleeved outside the lock nut 7, and the spring 6 is arranged between the top surface of the main valve disc 5 and the top surface of the sacrifice disc 4.

[0049] Therefore, when the sacrifice disc 4 is damaged, the discharge valve can be disassembled online, and the valve inner parts can be taken out. The lock nut 7 and the sacrifice disc 4 can be replaced, and the discharge valve can be used again after reassembly.

[0050] The locking nut 7 is sleeved on the bottom of the valve stem 20, for example, an external thread is arranged on the bottom of the valve stem 20, and the locking nut 7 is screwed on the bottom of the valve stem 20. The top surface of the main valve disc 5 can be fixedly connected with the top of the locking nut 7. The sacrifice valve disc 4 can be movably sleeved outside the locking nut 7, and the two can be relatively lifted and moved.

[0051] Specifically, the main valve disc 5 is provided in a cylindrical shape, the top surface of the main valve disc 5 is provided with a first through hole, and the bottom end is open; the valve stem 20 passes through the first through hole; the bottom outer wall of the sacrifice valve disc 4 is provided with an outwardly protruding annular first step surface 402, the main valve disc 5 is sleeved on the upper portion of the sacrifice valve disc 4, and the bottom surface of the main valve disc 5 is arranged above the first step surface 402.

[0052] Specifically, the main valve disc 5 is provided in a cylindrical shape, the top surface of the main valve disc 5 is provided with a first through hole, and the bottom end is open; the valve stem 20 passes through the first through hole; the bottom outer wall of the sacrifice valve disc 4 is provided with an outwardly protruding annular first step surface 402, the main valve disc 5 is sleeved on the upper portion of the sacrifice valve disc 4, and the bottom surface of the main valve disc 5 is arranged above the first step surface 402.

[0053] In some embodiments, the sacrifice valve disc 4 is provided in a cylindrical shape, the top surface of the sacrifice valve disc 4 is provided with a second through hole, and the bottom end is open; the valve stem 20 passes through the second through hole; the bottom outer wall of the locking nut 7 is provided with a protruding second step surface 701, and the top surface of the sacrifice valve disc 4 is arranged above the second step surface 701.

[0054] Specifically, the main valve disc 5 is provided in a cylindrical shape, the top surface of the main valve disc 5 is provided with a first through hole, and the bottom end is open; the valve stem 20 passes through the first through hole; the bottom outer wall of the sacrifice valve disc 4 is provided with an outwardly protruding annular first step surface 402, the main valve disc 5 is sleeved on the upper portion of the sacrifice valve disc 4, and the bottom surface of the main valve disc 5 is arranged above the first step surface 402. Figure 4 As shown in the drawings, as the valve stem 20 is gradually moved upward, the spring 6 is gradually stretched to the longest, until the shoulder of the locking nut 7 and the shoulder of the sacrifice valve disc 4 are in contact with each other, the main valve disc 5 and the sacrifice valve disc 4 become an integral whole under the tensioning action of the spring 6, and the two are simultaneously moved upward under the driving of the valve stem 20.

[0055] When the valve is closed, the main valve disc 5 is simultaneously moved downward together with the sacrifice valve disc 4, the throttling hole 401 of the sacrifice valve disc 4 is gradually hidden under the valve seat 2, until the bottom of the sacrifice valve disc 4 and the top of the valve seat 2 are in contact to form a tapered surface type contact surface, that is, the tapered surface type second auxiliary sealing structure 233 is closed. At this time, the flow equalizing hole 221 of the flow equalizing sleeve 22 is completely blocked by the outer wall of the main valve disc 5, the first auxiliary sealing structure 231 is closed, only gap flow exists in the pressure holding chamber 23, and the medium flow rate at the main sealing structure 231 is slow; then, the main valve disc 5 continues to move downward, the shoulder of the locking nut 7 and the shoulder of the sacrifice valve disc 4 are separated, the spring 6 is compressed, until the main sealing structure is closed, and the valve is fully closed.

[0056] Specifically, the annular first metal winding gasket 3 is arranged between the valve body 1 and the bottom of the valve seat 2, the packing ring 8 is arranged between the top of the main valve disc 5 and the valve stem 20, and the annular second metal winding gasket 9 is arranged between the top of the valve body 1 and the valve cover 10.

[0057] The upper surface of the valve cover 10 is connected with a hollow bracket 16, and the top of the valve stem 20 is arranged in the top of the bracket 16;

[0058] The bracket 16 is provided with a guide plate 15, and the guide plate 15 is provided with a guide hole, and the valve stem 20 passes through the guide hole;

[0059] The inner wall of the top of the valve cover 10 and the outer wall of the valve stem 20 are sequentially provided with an annular packing 11 and an annular packing 12 from bottom to top; the upper surface of the packing 12 is sequentially provided with an annular packing sleeve 13 and a packing plate 14 from bottom to top, and the packing plate 14 is connected with the top of the valve cover 10;

[0060] The top of the valve stem 20 is connected with a valve stem nut 21, the outer wall of the valve stem nut 21 and the inner wall of the top of the bracket 16 are connected with a bearing 18, and the top of the bracket 16 is connected with a bearing cover 19; the side wall of the bracket 16 at the position of the bearing 18 is provided with an oil cup 17.

[0061] The above is only an embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A discharge valve, characterized in that, include: The valve body has an internal cavity; The valve seat is installed inside the bottom of the valve body; A valve cover is attached to the top of the valve body; the valve cover has a rod hole. A valve stem passes through the rod hole and is movably disposed within the cavity; Both the main valve disc and the sacrificial disc are annular and are movably disposed within the cavity; the sacrificial disc is sleeved outside the bottom of the valve stem, and the main valve disc is sleeved outside the upper part of the sacrificial disc; a spring is disposed between the main valve disc and the sacrificial disc; a throttling orifice is formed on the lower side wall of the sacrificial disc. A flow equalization sleeve is disposed within the cavity; the flow equalization sleeve is sleeved outside the main valve disc, and flow equalization holes are formed on the side wall of the flow equalization sleeve, the total area of ​​the flow equalization holes being larger than the total area of ​​the throttling holes; A pressure-retaining cavity is provided between the inner wall of the flow equalization sleeve and the outer wall of the sacrificial valve. A main sealing structure, a first auxiliary sealing structure, and a second auxiliary sealing structure are provided in the pressure-retaining cavity. The first auxiliary sealing structure and the second auxiliary sealing structure are respectively provided 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 equalization sleeve. The second auxiliary sealing structure is formed by the contact between the sacrificial valve and the valve seat. A locking nut is provided below the main valve disc, and the locking nut is sleeved on the bottom of the valve stem; the sacrificial disc is sleeved on the locking nut, and the spring is disposed between the top surface of the main valve disc and the top surface of the sacrificial disc; The main valve disc is cylindrical with a first through hole on its top surface and an open bottom end; the valve stem passes through the first through hole; the bottom outer wall of the sacrificial disc is provided with an outwardly protruding, annular first stepped surface; the main valve disc is sleeved on the upper part of the sacrificial disc; the bottom surface of the main valve disc is located above the first stepped surface. The sacrificial petal is cylindrical with a second through hole on its top surface and an open 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 positioned above the second step surface.

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 thereis is also an inclined surface; the inclined surface slopes inward from top to bottom.

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

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

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

7. The discharge valve according to any one of claims 1-6, characterized in that, An annular first metal spiral wound gasket is provided between the bottom of the valve body and the valve seat, a packing ring is provided between the top of the main valve disc and the valve stem, and an annular second metal spiral wound gasket is provided 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 located inside the top of the bracket. The bracket is provided with a guide plate, the guide plate has a guide hole, and the valve stem passes through the guide hole; An annular packing pad and an annular packing are arranged sequentially from bottom to top between the inner top wall of the valve cover and the outer wall of the valve stem; an annular packing sleeve and a packing pressure plate are arranged sequentially 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 fitted onto the top of the valve stem, and a bearing is connected between the outer wall of the valve stem nut and the inner top wall of the bracket. A bearing cap 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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