Inverted pressure balance type plug valve with pressure release valve

Abstract

The invention relates to the technical field of plug valves, and discloses an inverted pressure balance type plug valve with a pressure release valve, which comprises a valve body and a plug body, and further comprises an automatic pressure release assembly, the automatic pressure release assembly comprises an automatic pressure release pipe and a return pipe, the automatic pressure release pipe is positioned outside the valve body, the front end of the automatic pressure release pipe is communicated to a valve cavity, one end of the return pipe is communicated to a flow inlet channel, and the other end of the return pipe is communicated to a flow outlet channel; one end of the balance pipe is communicated to the inflow channel, the other end of the balance pipe is communicated to the rear portion of the automatic pressure relief pipe, and the front end and the rear end of the pressurization spring abut against the opening and closing piston plate and the rear end of the automatic pressure relief pipe respectively. The manual pressure relief assembly is used for conducting pressure relief on the valve cavity before the plug valve is opened and comprises a manual pressure relief channel and an opening and closing mechanism. The plug valve can solve or at least relieve the problems that when the pressure of a middle cavity of an existing plug valve is too large, abrasion is prone to being accelerated, and the valve is not easy to open.

Description

Technical Field

[0001] The invention relates to the technical field of plug valves, and in particular to an inverted pressure-balanced plug valve with a pressure relief valve. Background Art

[0002] The plug valve uses a plunger with a through hole as the opening and closing part. The plunger rotates 90° with the valve stem to achieve the function of conducting or cutting off the fluid in the pipeline. The plug valve consists of a valve body, a plug, a valve stem, etc. The plug is conical, with large and small ends, large at the bottom and small at the top. It is installed from the bottom, so it is called "inverted installation"; the valve sealing performance is enhanced by adding lubricating sealing grease, so it is called "oil sealing".

[0003] Although the plug and the valve seat have the same taper and are precisely ground and installed in pairs, in fact, in addition to the rotational movement of the plug in the valve body, it also slightly moves in the direction perpendicular to the pipeline and in the axial direction, which is similar to the floating ball structure in the ball valve. According to the pressure balance principle of the plug valve, the plug can move up and down in the valve body. There is an adjustment screw at the bottom of the large end of the plug valve. Tightening the adjustment screw will move the plug up to achieve "plugging". When the valve is in the closed position, the raised structure on the top of the plug valve and the groove at the bottom of the valve stem are parallel to the pipeline axis. This structure can ensure that when the valve is pressurized on one side, the pressure pushes the plug to slightly move along the pipeline axis toward the low-pressure side.

[0004] For example, a pressure-balanced inverted sleeve plug valve with online adjustable sealing pressure ratio is disclosed with publication number CN210118471U. The valve body is designed with a plug body that is small at the top and large at the bottom, and the plug body and the connecting block are designed to float. The plug body can be conveniently disassembled, assembled, and debugged through the opening at the lower end of the valve body, which is convenient for maintenance. The floating of the plug body and the valve stem avoids the increase in torque caused by the eccentricity of the plug body and the valve stem, and better realizes the sealing of the plug body. The sealing during floating is achieved by relying on the truncated cone shape at the upper and lower ends of the valve body, the inclined wall of the plug body, and the elastic bushing. The medium is introduced into the upper and lower fat storage cavities through the one-way valve. The pressure difference formed by the different bottom areas of the upper and lower ends of the plug body by the medium pressure is used to keep the plug body moving toward the valve stem. As the pipeline medium pressure increases, the force of the plug body moving toward the valve stem increases, and the pressure ratio is automatically enhanced to achieve a self-sealing effect. On the other hand, an adjusting screw is provided to adjust the active position of the plug body, so as to facilitate the adjustment of the sealing pressure ratio when the pressure is low.

[0005] Although this solution can automatically increase the specific pressure as the pipeline medium pressure increases to achieve a self-sealing effect. However, when the plug valve is closed and sealed, the middle cavity of the valve body is a closed cavity. When the ambient temperature rises, the pressure in the middle cavity may increase, causing the plug body to squeeze the valve body with too much force, which can easily accelerate the wear of the plug body and the valve body. In addition, although this solution can easily rotate the valve stem after the pressure is released, the torque required for the initial rotation of the plug body in the closed state is the largest, especially for large-diameter plug valves. When the pressure in the middle cavity of the valve body is too high, the valve often cannot be opened. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art, solve or at least alleviate the problem that the existing plug valve is prone to accelerated wear and difficulty in opening the valve when the pressure in the middle cavity is too high, and provide an inverted pressure balanced plug valve with a pressure relief valve.

[0007] To achieve the above-mentioned object, the present invention provides the following technical solutions: an inverted pressure-balanced plug valve with a pressure relief valve, comprising a valve body and a plug body, a valve cavity is arranged in the middle of the valve body, an inlet channel and an outlet channel are respectively arranged at both ends of the valve cavity, the plug body is rotatably arranged in the valve cavity, the plug body is in a truncated cone shape with a small top and a large bottom, a through-flow channel is arranged in the middle of the plug body, and further comprising: An automatic pressure relief assembly, which is used to prevent excessive pressure in the valve cavity when the plug valve is in a closed state, and the automatic pressure relief assembly includes: An automatic pressure relief pipe, the automatic pressure relief pipe is located outside the valve body and the front end of the automatic pressure relief pipe is connected to the valve cavity; A reflux pipe, which is used to make the medium in the valve cavity return to the inlet channel, one end of the reflux pipe is connected to the inlet channel, and the other end is connected to the middle of the automatic pressure relief pipe; An opening and closing piston plate, which is used to control the opening and closing of the reflux pipe, and the opening and closing piston plate is sealingly and slidably arranged in the automatic pressure relief pipe; A balance pipe, which is used to adjust the position of the opening and closing piston plate, one end of the balance pipe is connected to the inlet channel, and the other end is connected to the rear of the automatic pressure relief pipe; A pressure spring, wherein the pressure spring is located in the automatic pressure relief pipe, and the front and rear ends of the pressure spring respectively abut against the opening and closing piston plate and the rear end of the automatic pressure relief pipe; The manual pressure relief assembly is used to relieve pressure in the valve cavity before the plug valve is opened. The manual pressure relief assembly includes: A manual pressure relief channel, one end of which is connected to the valve cavity, and the other end of which is connected to the outflow channel; An opening and closing mechanism is used to control the opening and closing state of the manual pressure relief channel.

[0008] In order to further realize the present invention, the following technical solutions may be preferably selected: Preferably, the automatic pressure relief assembly further comprises: A positioning piston plate is used to adjust the elastic force of the pressure spring. The positioning piston plate is axially sealed and slidably arranged at the rear of the automatic pressure relief pipe. The positioning piston plate is located behind the connection point between the balance pipe and the automatic pressure relief pipe. The rear end of the pressure spring abuts against the positioning piston plate. The regulating rod is used to regulate the position of the positioning piston plate. The front end of the regulating rod is fixedly connected to the positioning piston plate, and the middle part of the regulating rod is threadedly sleeved on the rear part of the automatic pressure relief pipe.

[0009] Preferably, it also includes a reinforcing rib, which is used to improve the strength of the valve body. The reinforcing rib is arranged on the outside of the valve body and is integrally formed with the valve body. The manual pressure relief channel is located inside the reinforcing rib.

[0010] Preferably, the opening and closing mechanism includes an opening and closing rod, which is located in the middle of the manual pressure relief channel, and the length direction of the opening and closing rod is perpendicular to the length direction of the middle of the manual pressure relief channel, and the opening and closing rod includes: An opening and closing section, which is located at the front end of the opening and closing rod, and the opening and closing section slides in a radial sealing manner along the manual pressure relief channel. When the opening and closing section is located in the manual pressure relief channel, the manual pressure relief channel is in a closed state; A positioning section is located at the rear end of the opening and closing rod and is used to control the position state of the opening and closing section. The positioning section is threadedly sleeved in the reinforcing rib.

[0011] Preferably, a small end cavity is formed between the upper end surface of the plug body and the upper inner surface of the valve cavity, and a large end cavity is formed between the lower end surface of the plug body and the lower inner surface of the valve cavity; A longitudinal pressure balancing hole is arranged in the plug body, and the upper and lower ends of the pressure balancing hole are respectively connected to the small end cavity and the large end cavity. A one-way valve is arranged in the pressure balancing hole, and the flow direction of the one-way valve is from the large end cavity to the small end cavity, and the pressure balancing hole does not pass through the flow channel of the plug body.

[0012] Preferably, a compensating sealing mechanism is further included, which is used to compensate for the wear of the plug body and the valve body and ensure the sealing between the plug body and the valve body. The compensating sealing mechanism includes: Sealing plates, which are two relatively mirror-imaged plates, are transversely slidably arranged on the plug body, and the sealing plates are sealingly slidably fitted to the inner surface of the valve cavity. When the plug valve is in a closed state, one of the sealing plates is located at the connection between the inlet channel and the valve cavity, and the other sealing plate is located at the connection between the outlet channel and the valve cavity; A driving hole, wherein the driving hole is transversely arranged in the plug body, the length direction of the driving hole is perpendicular to the length direction of the circulation channel, one end of the driving hole is connected to the circulation channel, and the other end is connected to the outer wall of the plug body; A piston rod, one end of which is fixedly connected to the sealing plate, and the other end of which is sealingly slidably arranged in the driving hole.

[0013] Preferably, the compensating sealing mechanism further comprises: A compensation spring, wherein the compensation spring is located in the driving hole and sleeved on the piston rod, and the compensation spring drives the sealing plate to translate toward the outside of the plug body; The sealing ring is sleeved on the piston rod, the inner wall of the sealing ring is sealingly fitted to the circumferential outer wall of the piston rod, and the outer wall of the sealing ring is sealingly fitted to the inner wall of the driving hole, and the two ends of the compensation spring are respectively against the sealing plate and the sealing ring.

[0014] Preferably, the driving hole comprises: A driving section, the driving section is located at one end of the driving hole close to the circulation channel, and the end of the piston rod is sealingly and slidably disposed in the driving section; The sealing section is located at one end of the driving hole away from the circulation channel. The sealing section is in the shape of a truncated cone hole with a larger outside and a smaller inside. The diameter of the small end of the sealing section is larger than the diameter of the driving section. The sealing ring is located in the sealing section, and the outer wall of the sealing ring is in the shape of a truncated cone corresponding to the inner wall of the sealing section.

[0015] Preferably, the gap between the lower outer surface of the plug body and the lower inner surface of the valve cavity is larger than the gap between the upper outer surface of the plug body and the upper inner surface of the valve cavity.

[0016] Preferably, it also includes a grease injection mechanism, which is used to inject grease into the space between the valve body and the plug body, and the grease injection mechanism includes: A grease injection hole, wherein the grease injection hole is located in the valve body, one end of the grease injection hole is connected to the small end cavity, and the other end is connected to the valve body; A grease guide groove is arranged on the outer wall of the plug body along the length direction of the plug body, and grease guide grooves are arranged on both sides of the two sealing plates.

[0017] The beneficial effects of the present invention are: 1. The present invention uses an automatic pressure relief component to make the pressure in the valve cavity reach a set value, and the valve cavity is connected to the inlet channel to release the pressure in the valve cavity to the valve inlet pipeline, thereby avoiding excessive pressure in the valve cavity and reducing the wear between the plug body and the valve body. The pressure in the valve cavity is ensured to be higher than a certain value of the valve inlet pressure by a balancing pipe and a pressure spring before the pressure is relieved, so that the pressure in the valve cavity will not be too low in the closed state, thereby ensuring the sealing between the plug body and the valve body.

[0018] 2. The present invention releases the pressure in the valve cavity to the valve outlet pipeline through the manual pressure relief component before the plug valve is opened. Before the release, the valve outlet pipeline is in a pressure-free state and the pressure relief speed is fast. After the pressure relief, the manual pressure relief component is closed. At this time, the plug body moves downward, and the gap between the plug body and the valve cavity increases, making it easier to rotate the valve stem to open the valve.

[0019] 3. The present invention realizes the seal between the plug body and the valve body through the sealing plate, which makes it easier to control the gap between the plug body and the valve body. When the valve is closed, the pressure in the valve cavity pushes the sealing plate to translate outward, so that the sealing plate fits tightly to the valve cavity, and can actively compensate for the wear of the valve body and the plug body, which not only ensures the sealing performance, but also improves the service life of the valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is one of the structural cross-sectional views of the present invention; Figure 3For the present invention Figure 2 The enlarged view of point A in the middle; Figure 4 This is the second structural cross-sectional view of the present invention; Figure 5 For the present invention Figure 4 The enlarged view of point B in the middle; Figure 6 For the present invention Figure 4 Enlarged view of point C in the middle; Figure 7 It is a structural schematic diagram of the valve body of the present invention; Figure 8 It is a structural cross-sectional view of the valve body of the present invention; Fig. 9 It is a schematic structural diagram of the plug body of the present invention; Fig.10 is a top view of the plug body of the present invention; Fig.11 For the present invention Fig.10 Sectional view at DD in the middle; Fig.12 For the present invention Fig.10 Sectional view at EE; Fig.13 It is a structural schematic diagram of the sealing plate and the piston rod of the present invention; Fig.14 It is a structural schematic diagram of the opening and closing rod of the present invention.

[0021] The accompanying drawings are marked as follows: 1-valve body; 2-plug body; 3-valve cavity; 4-inlet channel; 5-outlet channel; 6-circulation channel; 7-automatic pressure relief pipe; 8-reflux pipe; 9-opening and closing piston plate; 10-balancing pipe; 11-pressure spring; 12-manual pressure relief channel; 13-positioning piston plate; 14-regulating rod; 15-reinforcement rib; 16-opening and closing rod; 17-opening and closing section; 18-positioning section; 19-small end cavity; 20-large end cavity; 21-pressure balance hole; 22-sealing plate; 23-piston rod; 24-driving hole; 25-driving section; 26-sealing section; 27-compensation spring; 28-sealing ring; 29-grease injection hole; 30-grease guide groove. DETAILED DESCRIPTION

[0022] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0024] Embodiment 1 In addition to rotational motion, the plug of the existing plug valve also slightly moves in the direction of the vertical pipe and in the axial direction in the valve body 1, which is similar to the floating ball structure in the ball valve. According to the pressure balance principle of the plug valve, the plug can move up and down in the valve body 1. When the valve is in the closed position, the outer surfaces of the large end and the small end respectively form the large end valve cavity 3 and the small end valve cavity 3 with the inner surface of the valve body 1. Because they are connected by the balance hole, the air pressure in the two cavities is equal. However, the large end has a large cross-sectional area and is subjected to a large force, while the small end has a small cross-sectional area and is subjected to a small force. Therefore, the combined force is upward, which tightens the plug upward, making the valve easier to seal. When opening the valve, the large end will release pressure instantly, but there is a one-way valve in the balance hole of the small end, which cannot release pressure. The pressure pushes the plug downward, making the valve easier to open.

[0025] However, when the plug valve is closed and sealed, the middle cavity of the valve body 1 is a closed cavity. When the ambient temperature rises, the pressure in the middle cavity may rise, causing the plug body 2 to push against the valve body 1 with too much force, which can easily accelerate the wear of the plug body 2 and the valve body 1. In addition, although the valve stem can be rotated relatively easily after the pressure is released, the torque required for the initial rotation of the plug body 2 in the closed state is the largest, especially for plug valves with large pipe diameters. When the pressure in the middle cavity of the valve body 1 is too high, the valve often cannot be opened.

[0026] Reference Figures 1 to 14 A pressure-balanced plug valve with an inverted pressure relief valve comprises a valve body 1 and a plug body 2. A valve cavity 3 is arranged in the middle of the valve body 1. An inlet channel 4 and an outlet channel 5 are arranged at both ends of the valve cavity 3. The plug body 2 is rotatably arranged in the valve cavity 3. The plug body 2 is in the shape of a truncated cone with a small top and a large bottom. A penetrating flow channel 6 is arranged in the middle of the plug body 2. The plug body 2 also comprises an automatic pressure relief component and a manual pressure relief component.

[0027] The automatic pressure relief assembly is used to prevent excessive pressure in the valve chamber 3 when the plug valve is in a closed state. The automatic pressure relief assembly includes an automatic pressure relief pipe 7, a reflux pipe 8, an opening and closing piston plate 9, a balance pipe 10 and a pressure spring 11.

[0028] The automatic pressure relief pipe 7 is located outside the valve body 1 and its front end is connected to the valve cavity 3. The reflux pipe 8 is used to return the medium in the valve cavity 3 to the inlet channel 4. One end of the reflux pipe 8 is connected to the inlet channel 4, and the other end is connected to the middle of the automatic pressure relief pipe 7. The opening and closing piston plate 9 is used to control the opening and closing of the reflux pipe 8. The opening and closing piston plate 9 is sealingly and slidably arranged in the automatic pressure relief pipe 7. The balance pipe 10 is used to adjust the position state of the opening and closing piston plate 9. One end of the balance pipe 10 is connected to the inlet channel 4, and the other end is connected to the rear part of the automatic pressure relief pipe 7. The pressure spring 11 is located in the automatic pressure relief pipe 7, and the front and rear ends of the pressure spring 11 respectively press against the opening and closing piston plate 9 and the rear end of the automatic pressure relief pipe 7.

[0029] The manual pressure relief assembly is used to relieve pressure in the valve chamber 3 before the plug valve is opened. The manual pressure relief assembly includes a manual pressure relief channel 12 and an opening and closing mechanism. One end of the manual pressure relief channel 12 is connected to the valve chamber 3, and the other end is connected to the outflow channel 5. The opening and closing mechanism is used to control the opening and closing state of the manual pressure relief channel 12.

[0030] In order to adjust the elastic force of the pressure spring 11, the automatic pressure relief assembly also includes a positioning piston plate 13 and a regulating rod 14. The positioning piston plate 13 is axially sealed and slidably arranged at the rear of the automatic pressure relief pipe 7. The positioning piston plate 13 is located behind the connection between the balance pipe 10 and the automatic pressure relief pipe 7. The rear end of the pressure spring 11 reaches the positioning piston plate 13. The regulating rod 14 is used to adjust the position of the positioning piston plate 13. The front end of the regulating rod 14 is fixedly connected to the positioning piston plate 13, and the middle part of the regulating rod 14 is threadedly sleeved on the rear of the automatic pressure relief pipe 7.

[0031] In order to optimize the product structure, the present embodiment further includes a reinforcing rib 15 for increasing the strength of the valve body 1 . The reinforcing rib 15 is disposed on the outside of the valve body 1 and is integrally formed with the valve body 1 . The manual pressure relief channel 12 is located inside the reinforcing rib 15 .

[0032] The opening and closing mechanism includes an opening and closing rod 16 , which is located in the middle of the manual pressure relief channel 12 . The length direction of the opening and closing rod 16 is perpendicular to the length direction of the middle of the manual pressure relief channel 12 . The opening and closing rod 16 includes an opening and closing section 17 and a positioning section 18 .

[0033] The opening and closing section 17 is located at the front end of the opening and closing rod 16 , and the opening and closing section 17 slides radially and sealingly along the manual pressure relief channel 12 . When the opening and closing section 17 is located in the manual pressure relief channel 12 , the manual pressure relief channel 12 is in a closed state.

[0034] The positioning section 18 is located at the rear end of the opening and closing rod 16 and is used to control the position of the opening and closing section 17 . The positioning section 18 is threadedly sleeved into the reinforcing rib 15 .

[0035] The present invention uses an automatic pressure relief component to make the pressure in the valve cavity 3 reach a set value, and the valve cavity 3 is connected to the inlet channel 4, and the pressure in the valve cavity 3 is released to the valve inlet pipeline, thereby avoiding excessive pressure in the valve cavity 3 and reducing wear between the plug body 2 and the valve body 1. The pressure in the valve cavity 3 is ensured to be higher than the valve inlet pressure by a certain value by the balance pipe 10 and the pressure spring 11 before the pressure is relieved, so that the pressure in the valve cavity 3 will not be too low in the closed state, thereby ensuring the sealing between the plug body 2 and the valve body 1.

[0036] When the pressure in the valve chamber 3 is lower than the sum of the valve inlet pressure and the elastic force of the pressure spring 11, the opening and closing piston plate 9 is located in front of the connection point between the reflux pipe 8 and the automatic pressure relief pipe 7. At this time, the valve chamber 3 is in a sealed state, and the pressure in the valve chamber 3 causes the plug body 2 to move upward to ensure the sealing of the valve.

[0037] When the pressure in the valve chamber 3 is higher than the sum of the valve inlet pressure and the elastic force of the pressure-adding spring 11, the opening and closing piston plate 9 moves backward, and the opening and closing piston plate 9 moves to the rear of the connection point of the return pipe 8 and the automatic pressure relief pipe 7. At this time, the valve chamber 3 is connected to the valve inlet pipeline, and the pressure in the valve chamber 3 is equal to the pressure in the valve inlet pipeline. Then the elastic force of the pressure-adding spring 11 drives the opening and closing piston plate 9 to move forward, and the opening and closing piston plate 9 moves to the front of the connection point of the return pipe 8 and the automatic pressure relief pipe 7, so that the valve chamber 3 is in a sealed state again. During this process, the pressure in the valve chamber 3 is not lower than the pressure in the valve inlet pipeline, so that the plug body 2 maintains its position state, thereby ensuring the sealing of the valve.

[0038] When the plug valve needs to be opened, the pressure in the valve cavity 3 is first released to the valve outlet pipeline through the manual pressure relief assembly. Before the release, the valve outlet pipeline is in a pressure-free state and the pressure relief speed is fast. After the pressure relief, the manual pressure relief assembly is closed. At this time, the plug body 2 moves downward, and the gap between the plug body 2 and the valve cavity 3 increases, making it easier to turn the valve stem to open the valve.

[0039] Embodiment 2 The existing plug valve has small holes at the top of the small end and the bottom of the large end of the plug body 2, which are directly connected to the flow channel 6 of the plug body 2. A one-way valve is provided in the small hole leading to the small end, so that the medium can only flow from the large end to the small end, but cannot flow from the small end to the large end. When the valve is in the closed position, the outer surfaces of the large end and the small end respectively form the large end valve cavity 3 and the small end valve cavity 3 with the inner surface of the valve body 1. Because they are connected by the small holes, the air pressure in the two cavities is equal. However, the large end has a large cross-sectional area and is subjected to a large force, while the small end has a small cross-sectional area and is subjected to a small force. Therefore, the combined force is upward, "tightening" the plug body 2 upward, making the valve easier to seal. When opening the valve, the large end will release pressure instantly, but there is a one-way valve in the balance hole of the small end, which cannot release pressure. The pressure pushes the plug downward, making the valve easier to open.

[0040] The medium in the valve of this structure enters the large end through the small hole. After long-term operation, the impurities in the medium will settle and accumulate in the large end. If they are not removed in time, they may hinder the movement of the sealing slide, causing the valve to not close properly and fail to seal reliably, increase the switching torque, and even cause the valve to get stuck.

[0041] Reference Figures 2 to 12 A small end cavity 19 is formed between the upper end surface of the plug body 2 and the upper inner surface of the valve cavity 3, and a large end cavity 20 is formed between the lower end surface of the plug body 2 and the lower inner surface of the valve cavity 3.

[0042] A longitudinal pressure balance hole 21 is provided in the plug body 2, and the upper and lower ends of the pressure balance hole 21 are respectively connected to the small end cavity 19 and the large end cavity 20. A one-way valve is provided in the pressure balance hole 21, and the flow direction of the one-way valve is from the large end cavity 20 to the small end cavity 19. The pressure balance hole 21 does not pass through the flow channel 6 of the plug body 2.

[0043] The gap between the lower outer surface of the plug body 2 and the lower inner surface of the valve cavity 3 is larger than the gap between the upper outer surface of the plug body 2 and the upper inner surface of the valve cavity 3 .

[0044] The plug valve also includes a grease injection mechanism, which is used to inject grease into the space between the valve body 1 and the plug body 2. The grease injection mechanism includes a grease injection hole 29 and a grease guide groove 30. The grease injection hole 29 is located in the valve body 1. One end of the grease injection hole 29 is connected to the small end cavity 19, and the other end is connected to the outside of the valve body 1. The grease guide groove 30 is arranged on the outer wall of the plug body 2 along the length direction of the plug body 2, and grease guide grooves 30 are provided on both sides of the two sealing plates 22.

[0045] The pressure balance hole 21 of the present invention is located on the side of the plug body 2, and the pressure balance hole 21 is not directly connected to the medium flow channel, thereby preventing foreign particles in the medium from entering the large end cavity 20. The pressure of the large end cavity 20 of a conventional plug valve is introduced through a balance hole directly connected to the medium flow channel, and is also passed through the balance hole during pressure relief, but the pressure of the large end cavity 20 of the present invention is introduced through the gap between the lower outer surface of the plug body 2 and the lower inner surface of the valve cavity 3, and foreign particles in the medium cannot enter the large end cavity 20 through the gap.

[0046] Embodiment 3 The solution of embodiment 2 connects the valve cavity 3 with the large end cavity 20 through a gap, which puts higher requirements on the processing accuracy and taper design of the plug body 2 and the valve body 1. In particular, when the plug body 2 and the valve body 1 are worn, scratched, deformed, etc., poor sealing or the valve cannot be opened may easily occur.

[0047] Reference Figures 2 to 13 The plug valve also includes a compensating sealing mechanism, which is used to compensate for the wear of the plug body 2 and the valve body 1 and ensure the sealing between the plug body 2 and the valve body 1. The compensating sealing mechanism includes a sealing plate 22, a driving hole 24 and a piston rod 23.

[0048] There are two sealing plates 22 arranged in relative mirror images. The sealing plates 22 are laterally slidably arranged on the plug body 2. The sealing plates 22 are sealingly slidably fitted on the inner surface of the valve cavity 3. When the plug valve is in a closed state, one of the sealing plates 22 is located at the connection between the inlet channel 4 and the valve cavity 3, and the other sealing plate 22 is located at the connection between the outlet channel 5 and the valve cavity 3.

[0049] The driving hole 24 is transversely arranged in the plug body 2 , and the length direction of the driving hole 24 is perpendicular to the length direction of the circulation channel 6 . One end of the driving hole 24 is connected to the circulation channel 6 , and the other end is connected to the outer wall of the plug body 2 .

[0050] One end of the piston rod 23 is fixedly connected to the sealing plate 22 , and the other end is sealingly slidably disposed in the driving hole 24 .

[0051] In order to ensure the sealing between the piston rod 23 and the driving hole 24 and provide power for the sealing plate 22 to translate outward, the compensation sealing mechanism also includes a compensation spring 27 and a sealing ring 28. The compensation spring 27 is located in the driving hole 24 and is sleeved on the piston rod 23. The compensation spring 27 drives the sealing plate 22 to translate outward from the plug body 2. The sealing ring 28 is sleeved on the piston rod 23. The inner wall of the sealing ring 28 is sealed against the circumferential outer wall of the piston rod 23, and the outer wall of the sealing ring 28 is sealed against the inner wall of the driving hole 24. The two ends of the compensation spring 27 respectively abut against the sealing plate 22 and the sealing ring 28.

[0052] In order to optimize the product structure, in this embodiment, the driving hole 24 includes a driving section 25 and a sealing section 26. The driving section 25 is located at one end of the driving hole 24 close to the circulation channel 6. The end of the piston rod 23 is sealed and slidably arranged in the driving section 25. The sealing section 26 is located at the end of the driving hole 24 away from the circulation channel 6. The sealing section 26 is in the shape of a truncated cone with a large outside and a small inside. The diameter of the small end of the sealing section 26 is larger than the diameter of the driving section 25. The sealing ring 28 is located in the sealing section 26, and the outer wall of the sealing ring 28 is in the shape of a truncated cone corresponding to the inner wall of the sealing section 26.

[0053] The sealing between the plug body 2 and the valve body 1 is achieved by the sealing plate 22, which makes it easier to control the gap between the plug body 2 and the valve body 1. During processing, the gap between the lower outer surface of the plug body 2 and the lower inner surface of the valve cavity 3 can be appropriately increased to ensure reliable communication between the large end cavity 20 and the valve cavity 3.

[0054] When the valve is closed, the pressure in the valve cavity 3 pushes the sealing plate 22 to translate outward, so that the sealing plate 22 fits tightly against the valve cavity 3, which can actively compensate for the wear of the valve body 1 and the plug body 2, not only ensuring the sealing performance, but also improving the service life of the valve.

[0055] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An inverted pressure-balanced plug valve with a pressure relief valve, comprising a valve body (1) and a plug body (2), wherein a valve cavity (3) is arranged in the middle of the valve body (1), and an inlet channel (4) and an outlet channel (5) are respectively arranged at two ends of the valve cavity (3), and the plug body (2) is rotatably arranged in the valve cavity (3), and the plug body (2) is in the shape of a truncated cone with a small upper portion and a large lower portion, and a through-flow channel (6) is arranged in the middle of the plug body (2), characterized in that: Also includes: An automatic pressure relief assembly is used to prevent excessive pressure in the valve chamber (3) when the plug valve is in a closed state, and the automatic pressure relief assembly comprises: An automatic pressure relief pipe (7), the automatic pressure relief pipe (7) being located outside the valve body (1) and having a front end connected to the valve cavity (3); a return pipe (8) for returning the medium in the valve chamber (3) to the inlet channel (4); one end of the return pipe (8) is connected to the inlet channel (4), and the other end is connected to the middle of the automatic pressure relief pipe (7); An opening and closing piston plate (9) for controlling the opening and closing of the reflux pipe (8), wherein the opening and closing piston plate (9) is sealingly slidably disposed in the automatic pressure relief pipe (7); A balance pipe (10) for adjusting the position state of the opening and closing piston plate (9), one end of the balance pipe (10) being connected to the inlet channel (4) and the other end being connected to the rear of the automatic pressure relief pipe (7); A pressure spring (11), wherein the pressure spring (11) is located in the automatic pressure relief pipe (7), and the front and rear ends of the pressure spring (11) respectively abut against the opening and closing piston plate (9) and the rear end of the automatic pressure relief pipe (7); A manual pressure relief assembly is used to relieve pressure in the valve chamber (3) before the plug valve is opened, and the manual pressure relief assembly comprises: A manual pressure relief channel (12), one end of the manual pressure relief channel (12) being connected to the valve chamber (3) and the other end of the manual pressure relief channel (12) being connected to the outflow channel (5); An opening and closing mechanism, wherein the opening and closing mechanism is used to control the opening and closing state of the manual pressure relief channel (12).

2. The inverted pressure-balanced plug valve with a pressure relief valve according to claim 1 is characterized in that: The automatic pressure relief assembly also includes: A positioning piston plate (13) is used to adjust the elastic force of the pressure spring (11). The positioning piston plate (13) is axially sealed and slidably arranged at the rear of the automatic pressure relief pipe (7). The positioning piston plate (13) is located behind the connection point between the balance pipe (10) and the automatic pressure relief pipe (7). The rear end of the pressure spring (11) abuts against the positioning piston plate (13). A regulating rod (14) is used to regulate the position of the positioning piston plate (13); the front end of the regulating rod (14) is fixedly connected to the positioning piston plate (13); the middle part of the regulating rod (14) is threadedly sleeved on the rear part of the automatic pressure relief pipe (7).

3. The inverted pressure-balanced plug valve with a pressure relief valve according to claim 1 is characterized in that: It also includes a reinforcing rib (15) for improving the strength of the valve body (1); the reinforcing rib (15) is arranged on the outside of the valve body (1) and is integrally formed with the valve body (1); and the manual pressure relief channel (12) is located within the reinforcing rib (15).

4. The inverted pressure-balanced plug valve with a pressure relief valve according to claim 3 is characterized in that: The opening and closing mechanism comprises an opening and closing rod (16), the opening and closing rod (16) being located in the middle of the manual pressure relief channel (12), the length direction of the opening and closing rod (16) being perpendicular to the length direction of the middle of the manual pressure relief channel (12), and the opening and closing rod (16) comprising: an opening and closing section (17) located at the front end of the opening and closing rod (16); the opening and closing section (17) slides in a radially sealed manner along the manual pressure relief channel (12); when the opening and closing section (17) is located in the manual pressure relief channel (12), the manual pressure relief channel (12) is in a closed state; A positioning section (18) is located at the rear end of the opening and closing rod (16) and is used to control the position state of the opening and closing section (17); the positioning section (18) is threadedly sleeved into the reinforcing rib (15).

5. The inverted pressure-balanced plug valve with a pressure relief valve according to claim 1, characterized in that: A small end cavity (19) is formed between the upper end surface of the plug body (2) and the upper inner surface of the valve cavity (3), and a large end cavity (20) is formed between the lower end surface of the plug body (2) and the lower inner surface of the valve cavity (3); A longitudinal pressure balancing hole (21) is provided in the plug body (2), and the upper and lower ends of the pressure balancing hole (21) are respectively connected to the small end cavity (19) and the large end cavity (20). A one-way valve is provided in the pressure balancing hole (21), and the flow direction of the one-way valve is from the large end cavity (20) to the small end cavity (19). The pressure balancing hole (21) does not pass through the flow channel (6) of the plug body (2).

6. The inverted pressure-balanced plug valve with a pressure relief valve according to claim 5, characterized in that: It also includes a compensating sealing mechanism, which is used to compensate for the wear of the plug body (2) and the valve body (1) and ensure the sealing between the plug body (2) and the valve body (1), and the compensating sealing mechanism includes: a sealing plate (22), wherein the two sealing plates (22) are arranged in mirror images relative to each other, the sealing plates (22) are arranged to slide transversely on the plug body (2), the sealing plates (22) are sealingly slidably fitted on the inner surface of the valve cavity (3), and when the plug valve is in a closed state, one of the sealing plates (22) is located at the connection between the inlet channel (4) and the valve cavity (3), and the other sealing plate (22) is located at the connection between the outlet channel (5) and the valve cavity (3); a driving hole (24), the driving hole (24) being arranged transversely in the plug body (2), the length direction of the driving hole (24) being perpendicular to the length direction of the circulation channel (6), one end of the driving hole (24) being connected to the circulation channel (6), and the other end being connected to the outer wall of the plug body (2); A piston rod (23), one end of the piston rod (23) is fixedly connected to the sealing plate (22), and the other end is sealingly slidably disposed in the driving hole (24).

7. The inverted pressure-balanced plug valve with a pressure relief valve according to claim 6, characterized in that: The compensating sealing mechanism also includes: A compensation spring (27), wherein the compensation spring (27) is located in the drive hole (24) and sleeved on the piston rod (23), and the compensation spring (27) drives the sealing plate (22) to translate toward the outside of the plug body (2); A sealing ring (28) is sleeved on the piston rod (23), the inner wall of the sealing ring (28) is sealingly fitted to the circumferential outer wall of the piston rod (23), and the outer wall of the sealing ring (28) is sealingly fitted to the inner wall of the drive hole (24), and the two ends of the compensation spring (27) respectively abut against the sealing plate (22) and the sealing ring (28).

8. The inverted pressure-balanced plug valve with a pressure relief valve according to claim 7, characterized in that: The driving hole (24) comprises: A driving section (25), the driving section (25) being located at one end of the driving hole (24) close to the circulation channel (6), and the end of the piston rod (23) being sealingly slidably disposed in the driving section (25); A sealing section (26), the sealing section (26) being located at one end of the driving hole (24) away from the circulation channel (6), the sealing section (26) being in the shape of a truncated cone hole with a larger outer portion and a smaller inner portion, the diameter of the small end of the sealing section (26) being larger than the diameter of the driving section (25), the sealing ring (28) being located in the sealing section (26), the outer wall of the sealing ring (28) being in the shape of a truncated cone corresponding to the inner wall of the sealing section (26).

9. The inverted pressure-balanced plug valve with a pressure relief valve according to claim 5, characterized in that: The gap between the lower outer surface of the plug body (2) and the lower inner surface of the valve cavity (3) is greater than the gap between the upper outer surface of the plug body (2) and the upper inner surface of the valve cavity (3).

10. The inverted pressure-balanced plug valve with a pressure relief valve according to claim 6, characterized in that: It also includes a grease injection mechanism, which is used to inject grease into the space between the valve body (1) and the plug body (2), and the grease injection mechanism includes: A grease injection hole (29), wherein the grease injection hole (29) is located in the valve body (1), one end of the grease injection hole (29) is connected to the small end cavity (19), and the other end of the grease injection hole (29) is connected to the outside of the valve body (1); A grease guide groove (30) is provided on the outer wall of the plug body (2) along the length direction of the plug body (2), and the grease guide groove (30) is provided on both sides of the two sealing plates (22).

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