A gate valve with replaceable stem sealing ring under pressure

Abstract

The present application relates to a gate valve with a valve stem seal ring that can be replaced under pressure, which includes a valve body, a valve cover, a valve plate, a first valve stem, and a second valve stem. A sealing assembly is provided between the second valve stem and the valve cover; the sealing assembly includes a fixed seal ring, a second mounting member, a movable member, and a clamping ring. The movable member is sleeved on the outside of the second valve stem. The second valve stem that moves downward can be threadedly engaged with the movable member and disengage the first valve stem from the second valve stem. The movable member threadedly connected to the second valve stem moves upward and abuts the clamping ring against the fixed seal ring. When the upper seal ring needs to be replaced, the second valve stem is moved to disengage the second valve stem from the first valve stem. Thereafter, the second valve stem is threadedly connected to the movable member, thereby driving the movable member to move toward the fixed seal ring during the rotation of the second valve stem, so that the clamping ring and the fixed seal ring remain in abutment. The second valve stem is threadedly engaged with the movable member, so that the gap between the second valve stem and the valve cover is closed.

Description

Technical Field

[0001] The present application relates to the technical field of gate valves, and in particular to a gate valve with a valve stem sealing ring that can be replaced under pressure. Background Art

[0002] Existing leak-proof, self-sealing valves consist of a valve body, bonnet, gland, valve plate, stem, and opening mechanism. During operation, the gate plate is raised and lowered to control the opening and closing of the valve, thereby connecting or disconnecting the medium in the pipeline. A sealing ring is also installed between the stem and gland to prevent leakage of the medium in the pipeline. However, the sealing ring is a wearable part and requires frequent replacement to prevent leakage.

[0003] The above-mentioned sealing form cannot replace the sealing ring in the working state, that is, it cannot be replaced when the pipeline is running without water and under pressure. The sealing ring can only be replaced after the pipeline pressure is cut off and the pressure cap is removed. The disassembly and replacement is very inconvenient. The replacement requires the pipeline to be stopped, which affects the subsequent use needs and is inconvenient to use.

[0004] Therefore, it is necessary to propose a new technical solution to solve the above problems. Summary of the Invention

[0005] In order to replace the sealing ring without stopping the operation of the pipeline, the present application provides a gate valve with a valve stem sealing ring that can be replaced under pressure.

[0006] This application provides a gate valve with a replaceable stem seal ring under pressure, which adopts the following technical solution:

[0007] A gate valve with a valve stem sealing ring that can be replaced under pressure, comprising a valve body with an opening at one end, a valve cover for closing the valve body opening, a valve plate slidably arranged in the valve body, a first valve stem for driving the valve plate to move, a second valve stem for driving the first valve stem to rotate, a sealing assembly being arranged between the second valve stem and the valve cover, the first valve stem being rotatably connected to the valve body, the first valve stem being passed through the valve plate and being threadedly engaged with the valve plate, the second valve stem being passed through the valve cover and being slidably engaged with the valve cover, the lower end of the second valve stem being able to be clamped with the upper end of the first valve stem, the valve cover being detachably connected to a cover plate, an upper sealing ring being arranged between the cover plate and the second valve stem, and the valve body having a water inlet and a water outlet for passing a fluid;

[0008] The sealing assembly includes a fixed sealing ring fixed on the inner wall of the valve cover, a second mounting part connected to the valve body, a movable part slidably arranged on the second mounting part, and a clamping ring arranged on the movable part. The movable part is sleeved on the outside of the second valve stem. The second valve stem moving downward can be threadedly engaged with the movable part and disengage the first valve stem and the second valve stem. The movable part threadedly connected to the second valve stem moves upward and makes the clamping ring abut against the fixed sealing ring. There is a gap between the inner walls of the fixed sealing ring and the clamping ring and the second valve stem.

[0009] By adopting the above technical solution: when the upper sealing ring needs to be replaced, the second valve stem is moved to disengage the second valve stem from the first valve stem, and then the second valve stem is threadedly connected to the movable part, thereby driving the movable part to move toward the fixed sealing ring during the rotation of the second valve stem, so that the clamping ring and the fixed sealing ring are kept in contact, and the second valve stem is threadedly engaged with the movable part, so that the gap between the second valve stem and the valve cover is closed, making it difficult for liquid to leak from the gap between the second valve stem and the valve cover, so that the upper sealing ring on the second valve stem can be directly replaced.

[0010] Optional: An installation groove is provided on the first valve stem, a retaining ring is fixed to the upper end of the first valve stem, and a clamping block is provided at the lower end of the second valve stem. The clamping block can be clamped in the inner cavity of the retaining ring, and the clamping block can rotate in the installation groove and a gap is left between the side wall of the clamping block and the inner wall of the installation groove.

[0011] By adopting the above technical solution, after the second valve stem moves downward, the clamping block on the second valve stem is disconnected from the clamping ring, so that during the rotation of the second valve stem, the first valve stem will not be driven to move, the position of the valve plate will not change, and the normal use of the gate valve will not be easily affected.

[0012] Optionally, the upper end of the clamping block is provided with a chamfer.

[0013] By adopting the above technical solution, after the clamping block rotates in the installation groove, when the second valve stem moves upward, the chamfer can first contact the inner wall of the clamping ring, and the inclined surface of the chamfer can be used to guide the rotation of the clamping block, so that the clamping block can be aligned with the inner wall of the clamping ring, thereby making it easier for the clamping block to enter the clamping ring.

[0014] Optional: The clamping block is rotatably connected to the lower end of the second valve stem, and a sliding groove is provided at one end of the clamping block close to the valve stem. The sliding groove is arranged around the rotation axis of the clamping block, and a slider is fixed to the lower end of the second valve stem. The slider is embedded in the sliding groove and slides and can drive the second clamping block to rotate synchronously with the second valve stem.

[0015] By adopting the above technical solution, during the upward movement of the second valve stem, the clamping block can automatically rotate under the push of the chamfer, so that the clamping block can more easily enter the clamping ring. At the same time, the second valve stem can also drive the clamping block to rotate when it rotates, which will not affect the rotation of the first valve stem driven by the second valve stem.

[0016] Optionally, a first guide slope is provided on one end of the outer wall of the fixed sealing ring close to the clamping ring, and a second guide slope is provided on one end of the inner wall of the clamping ring close to the fixed sealing ring, and the first guide slope and the second guide slope abut against each other.

[0017] By adopting the above technical solution, when the fixed sealing ring and the clamping ring abut against each other, the first guide bevel and the second guide bevel can guide each other, making it easier for the first guide bevel to align with the second guide bevel. At the same time, they can also be deformed when the two are squeezed, so that the sealing effect of the two is better.

[0018] Optionally, the inner wall diameter of the movable part is larger than the outer diameter of the second valve stem.

[0019] By adopting the above technical solution, when the movable part does not need to move but the second valve stem needs to rotate, the movable part will not contact the second valve stem, so that the rotation of the second valve stem is not easily affected. At the same time, when the movable part is not in use, its internal thread will not be worn due to contact with the second valve stem.

[0020] Optionally: a limiting ring is provided between the valve cover and the cover plate, a limiting groove is coaxially provided on the second valve stem, and the inner wall of the limiting ring is sleeved in the limiting groove and slidingly engaged with the limiting groove.

[0021] By adopting the above technical solution, when the second valve stem moves along its axial direction, the limit ring is used to limit the axial movement distance of the second valve stem, so that the second valve stem will not move too much. After the second valve stem moves upward, the clamping block can be stably located in the clamping ring and will not fall directly.

[0022] Optional: Two limit pins are also passed through the cover plate, and an anti-idiot groove is coaxially opened on the second valve stem. The limit pins are arranged along the axis of the second valve stem, and the limit pins can be passed through the anti-idiot grooves respectively. When the limit pin located above is inserted into the anti-idiot groove, the clamping block is disconnected from the clamping ring, and the length of the anti-idiot groove is greater than the diameter of the limit pin.

[0023] By adopting the above technical solution, the position of the second valve stem relative to the first valve stem is determined by utilizing the cooperation between the limit pin and the anti-mistake groove, thereby preventing the second valve stem from being rotated before the clamping block has fully entered the installation groove.

[0024] In summary, this application includes at least one of the following beneficial technical effects:

[0025] 1. When the upper sealing ring needs to be replaced, the second valve stem is moved to disengage the second valve stem from the first valve stem. Then, the second valve stem is threadedly connected to the movable part. As the second valve stem rotates, the movable part is driven to move toward the fixed sealing ring, so that the clamping ring and the fixed sealing ring are kept in contact. The second valve stem is threadedly engaged with the movable part, so that the gap between the second valve stem and the valve cover is sealed, making it difficult for liquid to leak from the gap between the second valve stem and the valve cover. Therefore, the upper sealing ring on the second valve stem can be directly replaced.

[0026] 2. After the second valve stem moves downward, the clamping block under the second valve stem is disconnected from the clamping ring, so that during the rotation of the second valve stem, the first valve stem will not be driven to move, the position of the valve plate will not change, and the normal use of the gate valve will not be easily affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of an embodiment of the present application;

[0028] Figure 2 This is a schematic diagram showing the internal structure of the valve body according to an embodiment of the present application;

[0029] Figure 3 for Figure 2 A magnified view of part A;

[0030] Figure 4 for Figure 2 A magnified view of part B;

[0031] Figure 5 This is a schematic diagram illustrating the connection structure between the first valve stem and the second valve stem according to an embodiment of the present application;

[0032] Figure 6 This is a schematic diagram illustrating the connection structure between the movable member and the second valve stem according to an embodiment of the present application;

[0033] Figure 7 This is a schematic diagram of an embodiment of the present application for illustrating a structure for limiting the stop position of the second valve stem.

[0034] In the figure, 1, valve body; 11, valve plate; 12, positioning groove; 13, first mounting member; 131, mounting ring; 2, valve cover; 21, first sealing gasket; 22, second sealing gasket; 3, first valve stem; 31, protruding ring; 32, mounting groove; 33, clamping ring; 4, second valve stem; 41, handwheel; 42, upper sealing ring; 43, clamping block; 431, upper clamping part; 432, lower clamping part; 433, sliding groove; 4 34. Chamfer; 44. Slider; 45. Limit groove; 46. Anti-slip groove; 5. Cover plate; 51. Limit ring; 52. Limit pin; 521. Anti-slip groove; 53. Anti-slip pin; 6. Sealing assembly; 61. Fixed sealing ring; 611. First guide slope; 62. Second mounting part; 63. Movable part; 631. Guide groove; 64. Pressure ring; 641. Second guide slope; 65. Guide sleeve; 651. Guide block. DETAILED DESCRIPTION

[0035] The present application is further described in detail below with reference to the accompanying drawings.

[0036] The present application discloses a gate valve with a valve stem seal ring that can be replaced under pressure, such as Figure 1 and Figure 2 As shown, it includes a valve body 1 with an open end, a valve cover 2 for sealing the opening of the valve body 1, a valve plate 11 slidably disposed within the valve body 1, a first valve stem 3 for driving the valve plate 11, and a second valve stem 4 for rotating the first valve stem 3. A handwheel 41 is bolted to the upper end of the second valve stem 4. A water inlet and a water outlet are respectively formed on two side surfaces of the valve body 1 that are spaced apart from each other. Both the water inlet and the water outlet are connected to the inner cavity of the valve body 1. The valve plate 11 slides vertically within the inner cavity of the valve body 1 to seal the water inlet and the water outlet, thereby disconnecting the flow path in the pipeline after the valve plate 11 moves downward. A positioning groove 12 is coaxially defined at the upper end of the valve body 1. A first mounting member 13 is coaxially disposed within the positioning groove 12. The first mounting member 13 is embedded within the positioning groove 12, and its thickness is less than its depth. The first valve stem 3 is pivotally mounted on the first mounting member 13. The lower end of the first valve stem 3 is threadedly engaged with the valve plate 11, allowing the first valve plate 11 to move along the axis of the first valve stem 3 when the first valve stem 3 rotates. A protruding ring 31 is coaxially disposed on the first valve stem 3. One end of the protruding ring 31 abuts against an end of the first mounting member 13 near the opening of the valve body 1. A mounting ring 131 is also bolted to the first mounting member 13. The mounting ring 131 is fixed to the end surface of the first mounting member 13 near the opening of the valve body 1 and abuts against the end surface of the protruding ring 31 near the opening of the valve body 1, thereby preventing the relative position of the first valve stem 3 and the first mounting member 13 from changing.

[0037] like Figure 2 and Figure 3As shown, the valve cover 2 is fixedly connected to the valve body 1 by bolts, and a first sealing gasket 21 is also provided at the connection between the valve cover 2 and the valve body 1 to reduce liquid leakage. The upper end of the valve cover 2 is also fixed with a cover plate 5 by bolts, and a second sealing gasket 22 is also provided between the cover plate 5 and the valve cover 2 to reduce liquid leakage. The second valve stem 4 is passed through the cover plate 5 and the valve cover 2. The second valve stem 4 can rotate along its own axis and can also slide along its own axis. A plurality of upper sealing rings 42 are coaxially sleeved on the second valve stem 4. The upper sealing rings 42 abut against the through hole on the cover plate 5 for passing the second valve stem 4, thereby sealing the gap between the second valve stem 4 and the cover plate 5, making it difficult for the liquid in the valve body 1 to leak.

[0038] like Figure 4 and Figure 5 As shown, a mounting groove 32 is coaxially defined at the upper end of the first valve stem 3. A snap ring 33 is also fixed to the upper end of the first valve stem 3 using bolts. The inner cavity of the snap ring 33 is octagonal, and the edges of the inner cavity of the snap ring 33 are located within the mounting groove 32. The first valve stem 3 and the second valve stem 4 are coaxially disposed. The lower end of the second valve stem 4 is rotatably connected to a clamping block 43, which includes a lower clamping portion 432 and an upper clamping portion 431. The lower end of the second valve stem 4 is inserted through the upper clamping portion 431 and disposed between the upper clamping portion 431 and the lower clamping portion 432. The upper clamping portion 431 and the lower clamping portion 432 are fixed by bolts. The upper end of the upper clamping portion 431 is penetrated by a plurality of sliding grooves 433, which are arranged around the axis of the second valve stem 4. A slider 44 is fixed to the outer wall of the second valve stem 4 and embedded in the sliding groove 433, thereby enabling the clamping block 43 to rotate relative to the second valve stem 4 to a certain angle. Rotation of the second valve stem 4 also synchronously drives the clamping block 43 to rotate. The clamping block 43 can be completely sunk into the mounting groove 32 and disconnected from the retaining ring 33. A gap is left between the outer wall of the clamping block 43 and the inner wall of the mounting groove 32, so that rotation of the clamping block 43 does not drive rotation of the first valve stem 3. After the clamping block 43 moves into the retaining ring 33, it can abut against the inner wall of the retaining ring 33, driving rotation of the first valve stem 3 during the clamping block 43's rotation.

[0039] A chamfer 434 is provided at the edge of one end of the upper clamping portion 431 away from the lower clamping portion 432. The chamfer 434 can abut against the inner wall of the clamping ring 33 at one end close to the mounting groove 32, thereby guiding the clamping block 43 and making the clamping block 43 rotate at a certain angle so that the clamping block 43 is aligned with the inner cavity of the clamping ring 33, so that the clamping block 43 can be better inserted into the clamping ring 33.

[0040] like Figure 2 and Figure 3As shown, a sealing assembly 6 is also provided between the second valve stem 4 and the valve cover 2 to seal the gap formed by the second valve stem 4 passing through the valve cover 2. The sealing assembly 6 includes a fixed sealing ring 61 fixed on the inner wall of the valve cover 2, a second mounting member 62 provided on the valve body 1, a movable member 63 slidingly provided on the second mounting member 62, and a pressure ring 64 provided on the second movable member 63. The fixed sealing ring 61 is embedded in a groove provided in the inner cavity of the valve cover 2 at a position away from the valve body 1. The fixed sealing ring 61 is coaxially provided with the second valve stem 4 and surrounds the outside of the second valve stem 4. A gap is left between the inner wall of the fixed sealing ring 61 and the outer wall of the second valve stem 4. The second mounting member 62 is coaxially provided at the upper end of the first mounting member 13 and is located in the positioning groove 12. The first mounting member 13 and the second mounting member 62 abut against each other and are provided between the valve cover 2 and the valve body 1. The first mounting member 13 and the second mounting member 62 can be limited by the mutual squeezing between the valve cover 2 and the valve body 1. As shown Figure 6 As shown, a guide sleeve 65 is coaxially integrally formed on the upper end of the second mounting member 62. A guide groove 631 is defined within the guide sleeve 65. The movable member 63 is disposed within the guide sleeve 65 and slides vertically therein. A guide block 651 is integrally formed on the outer wall of the movable member 63. The guide block 651 is embedded in the guide groove 631, thereby limiting the movement of the movable member 63 relative to the guide sleeve 65, allowing the movable member 63 to move only along its own axis. The movable member 63 is sleeved onto the exterior of the second valve stem 4. The inner diameter of the movable member 63 is larger than the outer diameter of the second valve stem 4, thereby preventing the movable member 63 from affecting the vertical movement of the second valve stem 4. When the engaging block 43 at the lower end of the second valve stem 4 is located within the mounting groove 32, the second valve stem 4 is rotated so that the threads on the second valve stem 4 contact the internal threads on the movable member 63, allowing the movable member 63 to move toward the valve cover 2. The clamping ring 64 is installed at one end of the movable part 63 close to the valve cover 2. When the movable part 63 moves toward the valve cover 2, the clamping ring 64 can abut against the fixed sealing ring 61. At the same time, the movable part 63 is threadedly engaged with the second valve stem 4, so that the gap between the second valve stem 4 and the valve cover 2 is closed. When the cover plate 5 is disassembled and the upper sealing ring 42 is replaced, liquid leakage is not easy to occur.

[0041] like Figure 3 and Figure 6As shown, in order to achieve a better sealing effect between the fixed sealing ring 61 and the pressure ring 64, a first guiding bevel 611 is provided on the outer wall of the fixed sealing ring 61 at one end close to the pressure ring 64, and the end of the first guiding bevel 611 close to the pressure ring 64 is inclined toward the second valve stem 4. A second guiding bevel 641 is provided on the inner wall of the pressure ring 64 at one end close to the fixed sealing ring 61, and the end of the second guiding bevel 641 close to the fixed sealing ring 61 is inclined toward the second valve stem 4, so that when the fixed sealing ring 61 and the pressure ring 64 abut against each other, the first guiding bevel 611 and the second guiding bevel 641 can abut against each other, and a certain deformation and guidance will occur during the squeezing process between the two, so that the connection between the fixed sealing ring 61 and the pressure ring 64 is tighter.

[0042] like Figure 3 As shown, in order to limit the movement distance of the second valve stem 4 relative to the valve cover 2, a limit ring 51 is further provided between the valve cover 2 and the cover plate 5. The two ends of the limit ring 51 abut against the cover plate 5 and the valve cover 2 respectively, and the valve cover 2 and the cover plate 5 jointly limit the position of the limit ring 51. A limit groove 45 is coaxially provided on the second valve stem 4. A portion of the limit ring 51 is located within the limit groove 45 and is sleeved on the limit groove 45. When the position of the limit ring 51 is limited, the second valve stem 4 can move relative to the limit ring 51, so that the limit ring 51 and the limit groove 45 are in a relative position. Therefore, even if the second valve stem 4 can be displaced, it will not directly detach from the valve cover 2.

[0043] like Figure 3 and Figure 7 As shown, in order to clearly determine whether the clamping block 43 is located in the installation groove 32, two limit pins 52 are further provided on the cover plate 5. The limit pins 52 are arranged perpendicular to the second valve stem 4 and are arranged along the length of the second valve stem 4. A foolproof groove 46 is defined on the outer wall of the second valve stem 4. The two limit pins 52 can be inserted into the foolproof groove 46 respectively. The length of the foolproof groove 46 is greater than the diameter of the limit pins 52. When the limit pins 52 are inserted into the foolproof groove 46, the second valve stem 4 still has a certain amount of movement space. When the lower limit pin 52 is inserted into the foolproof groove 46, the clamping block 43 is located in the installation groove 32, preventing the second valve stem 4 from rotating the first valve stem 3. When the upper limit pin 52 is inserted into the foolproof groove 46, the clamping block 43 is located in the retaining ring 33, allowing the second valve stem 4 to rotate the first valve stem 3.

[0044] like Figure 7As shown, the cover plate 5 is also vertically penetrated with an anti-slip pin 53, and the limit pin 52 is provided with an anti-slip groove 521 along its length direction. The anti-slip pin 53 is penetrated in the anti-slip groove 521, so that when the limit pin 52 moves along its own axis, the anti-slip pin 53 is always located in the anti-slip groove 521, limiting the moving distance of the limit pin 52, so that the limit pin 52 can move without falling directly from the cover plate 5.

[0045] The working principle of this embodiment is as follows: Pull out both stop pins 52, then apply downward pressure to the hand wheel 41 so that the clamping block 43 enters the installation groove 32, push the lower stop pin 52 toward the cover plate 5, press the hand wheel 41 and rotate it, the movable member 63 is threadedly engaged with the second valve stem 4 and, driven by the second valve stem 4, moves toward the valve cover 2, causing the clamping ring 64 to abut against the fixed sealing ring 61. When the second valve stem 4 feels resistance to rotation, it stops rotating. Pull out the stop pin 52, remove the hand wheel 41 and cover plate 5, replace the upper sealing ring 42, install the cover plate 5 and hand wheel 41 after replacement, insert the lower stop pin 52 into the cover plate 5, rotate the hand wheel 41 in the opposite direction until the hand wheel 41 no longer feels resistance to rotation, and rotate it a few more times. Then, pull out the stop pin 52, move the second valve stem 4 upward until it can no longer move, and insert the upper stop pin 52 into the cover plate 5.

[0046] The embodiments of this specific implementation method are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A gate valve with a valve stem seal ring that can be replaced under pressure, characterized by: The invention comprises a valve body (1) with an opening at one end, a valve cover (2) for closing the opening of the valve body (1), a valve plate (11) slidably arranged in the valve body (1), a first valve stem (3) driving the valve plate (11) to move, and a second valve stem (4) for driving the first valve stem (3) to rotate, a sealing component (6) is arranged between the second valve stem (4) and the valve cover (2), the first valve stem (3) is rotatably connected to the valve body (1), the first valve stem (3) is passed through the valve plate (11) and is threadedly matched with the valve plate (11), the second valve stem (4) is passed through the valve cover (2) and is slidably matched with the valve cover (2), the lower end of the second valve stem (4) can be clamped with the upper end of the first valve stem (3), the valve cover (2) is detachably connected to a cover plate (5), an upper sealing ring (42) is arranged between the cover plate (5) and the second valve stem (4), and the valve body (1) has a water inlet and a water outlet for passing fluid; The sealing assembly (6) includes a fixed sealing ring (61) fixed on the inner wall of the valve cover (2), a second mounting member (62) connected to the valve body (1), a movable member (63) slidably arranged on the second mounting member (62), and a clamping ring (64) arranged on the movable member (63), wherein the movable member (63) is sleeved outside the second valve stem (4), and the second valve stem (4) moving downward can be threadedly engaged with the movable member (63) and disengage the first valve stem (3) from the second valve stem (4), and the movable member (63) threadedly connected to the second valve stem (4) moves upward and causes the clamping ring (64) to abut against the fixed sealing ring (61), and there is a gap between the inner walls of the fixed sealing ring (61) and the clamping ring (64) and the second valve stem (4).

2. A gate valve with a replaceable stem seal ring under pressure according to claim 1, characterized in that: The first valve stem (3) is provided with a mounting groove (32), the upper end of the first valve stem (3) is also fixed with a snap ring (33), and the lower end of the second valve stem (4) is provided with a clamping block (43), the clamping block (43) can be clamped in the inner cavity of the snap ring (33), the clamping block (43) can rotate in the mounting groove (32), and a gap is left between the side wall of the clamping block (43) and the inner wall of the mounting groove (32).

3. A gate valve with a replaceable stem seal ring under pressure according to claim 2, characterized in that: The upper end of the clamping block (43) is provided with a chamfer (434).

4. A gate valve with a replaceable stem seal ring under pressure according to claim 2, characterized in that: The clamping block (43) is rotatably connected to the lower end of the second valve stem (4); a sliding groove (433) is provided at one end of the clamping block (43) close to the valve stem; the sliding groove (433) is arranged around the rotation axis of the clamping block (43); a slider (44) is fixed to the lower end of the second valve stem (4); the slider (44) is embedded in the sliding groove (433) and slides and can drive the clamping block (43) to rotate synchronously with the second valve stem (4).

5. The gate valve with a replaceable stem seal ring under pressure according to claim 1, characterized in that: A first guiding inclined surface (611) is provided on one end of the outer wall of the fixed sealing ring (61) close to the pressure ring (64), and a second guiding inclined surface (641) is provided on one end of the inner wall of the pressure ring (64) close to the fixed sealing ring (61), and the first guiding inclined surface (611) and the second guiding inclined surface (641) are in contact with each other.

6. The gate valve with a replaceable stem seal ring under pressure according to claim 1, characterized in that: The inner wall diameter of the movable part (63) is larger than the outer diameter of the second valve stem (4).

7. The gate valve with a replaceable stem seal ring under pressure according to claim 1, characterized in that: A limiting ring (51) is provided between the valve cover (2) and the cover plate (5); a limiting groove (45) is coaxially provided on the second valve stem (4); the inner wall of the limiting ring (51) is sleeved in the limiting groove (45) and is slidably engaged with the limiting groove (45).

8. The gate valve with a replaceable stem seal ring under pressure according to claim 2, characterized in that: Two limit pins (52) are also provided on the cover plate (5), and an anti-idiot groove (46) is coaxially provided on the second valve stem (4). The limit pins (52) are arranged along the axis of the second valve stem (4). The limit pins (52) can be respectively provided in the anti-idiot groove (46). When the upper limit pin (52) is inserted into the anti-idiot groove (46), the clamping block (43) is disconnected from the clamping ring (33). The length of the anti-idiot groove (46) is greater than the diameter of the limit pin (52).

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