A valve with replaceable valve seat

Abstract

This invention relates to the field of valve sealing technology, specifically disclosing a valve with a replaceable valve seat, comprising a valve body, a valve seat, and a flow-blocking element. The valve body has a valve cavity, and the valve seat is installed within the valve cavity with an elastic sealing element between it and the inner wall of the valve cavity. Several pre-tightening bolts are threaded through the valve seat and screwed onto the inner wall of the valve cavity of the valve body, so that the valve seat presses the elastic sealing element against the inner wall of the valve cavity. When the flow-blocking element closes the valve, the valve seat, under the thrust of the flow-blocking element or the medium, further presses the elastic sealing element against the inner wall of the valve cavity. In this invention, the valve uses pre-tightening bolts to clamp the elastic sealing element between the valve seat and the valve body, achieving an initial seal between the valve seat and the valve body. When the valve is closed, the valve seat, under the thrust of the flow-blocking element and / or the medium, further presses the elastic sealing element against the inner wall of the valve cavity, thereby improving the sealing performance between the valve seat and the valve body, and simultaneously enabling disassembly.

Description

Technical Field

[0001] This invention belongs to the field of valve sealing technology, specifically a valve with a replaceable valve seat. Background Technology

[0002] Gate valves are among the most widely used valve types, applicable to a wide range of industries and operating conditions. They can be used at various pressures and temperatures, from normal to high and high temperatures, and even cryogenic conditions. Depending on the specific operating conditions, gate valves come in a variety of structures and performance characteristics.

[0003] The seals of normal temperature and low temperature gate valves are usually made of non-metallic soft materials. The valve seat can be floated relative to the valve body. Although this makes it easy to replace the valve seat during maintenance, it is not suitable for high temperature and high pressure conditions and cannot achieve the versatility of gate valves.

[0004] For high-temperature and high-pressure gate valves, because the valve seat must withstand high-temperature and high-pressure conditions, non-metallic soft materials cannot meet the requirements. The industry basically uses a fixed valve seat with a welded structure. However, this type of valve seat cannot be disassembled. When the valve seat's sealing performance decreases, the entire gate valve will be unable to be repaired, reducing the valve's service life. Therefore, there is an urgent need to design a valve with a replaceable valve seat to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a valve with a replaceable valve seat, which solves the problems of the floating valve seat mentioned above, which, although easy to replace, is not suitable for high temperature and high pressure conditions, and the fixed valve seat structure with welded structure cannot be disassembled, resulting in reduced sealing performance and inability to maintain.

[0006] To solve the above-mentioned technical problems, the present invention provides a valve with a replaceable valve seat, including a valve body, a valve seat, and a flow-blocking element. The valve body has a valve cavity, and the valve seat is installed within the valve cavity with an elastic sealing element between it and the inner wall of the valve cavity. Several pre-tightening bolts are threaded through the valve seat, and these bolts are screwed onto the inner wall of the valve cavity of the valve body, so that the valve seat presses the elastic sealing element tightly against the inner wall of the valve cavity of the valve body.

[0007] When the shut-off element closes the valve, the valve seat further presses the elastic seal against the inner wall of the valve cavity of the valve body under the thrust of the shut-off element or the medium.

[0008] Furthermore, the valve body is provided with two medium flow channels that are respectively connected to the valve cavity. An installation groove is provided on the inner wall of one of the medium flow channels of the valve body where it intersects with the valve cavity, or the installation groove is provided on the inner wall of the two medium flow channels of the valve body where they intersect with the valve cavity.

[0009] The number of valve seats is the same as the number of mounting slots, and one end of the valve seat is installed in the corresponding mounting slot.

[0010] Furthermore, mounting grooves are respectively formed on the inner walls of the two medium flow channels of the valve body where they intersect with the valve cavity.

[0011] The valve is a gate valve, and the shut-off element is the gate plate in the gate valve. The gate valve is provided with two valve seats. Each valve seat has several through holes evenly distributed on its edge. The inner wall of the valve cavity is provided with several threaded holes that correspond one-to-one with the several through holes. Each valve seat is provided with a pre-tightening bolt. The pre-tightening bolt passes through the through hole and is screwed into the threaded hole.

[0012] Furthermore, the mounting groove has a second section and a third section arranged sequentially in a direction away from the flow cut-off member. The inner diameter of the third section is smaller than that of the second section. A first stepped surface is formed at the connection between the third section and the second section. A sealing groove is formed between the first stepped surface and the hole wall of the second section. The elastic seal is disposed in the sealing groove, and both ends of the elastic seal abut against the first stepped surface and the valve seat, respectively.

[0013] Furthermore, the valve seat has a first conical surface on the side wall near the sealing groove. The first conical surface is inclined from the inside out in a direction away from the first step surface. The elastic sealing element is a sealing ring, and the sealing ring has a second conical surface that fits and conforms to the first conical surface.

[0014] Furthermore, the sealing ring is made of flexible graphite or flexible metal.

[0015] Furthermore, a boss is provided on the outer wall of the valve seat, and a plurality of through holes are evenly distributed along the edge of the boss.

[0016] The mounting groove has a first section, a second section, and a third section arranged sequentially in a direction away from the flow interceptor. The inner diameter of the second section is smaller than the inner diameter of the first section, and a second stepped surface is formed at the connection between the second section and the first section.

[0017] The second stepped surface is used to avoid the boss of the valve seat, and a plurality of the threaded holes are formed on the second stepped surface along the circumferential direction of the circular groove.

[0018] Furthermore, the inner diameter of the third segment is larger than the inner diameter of the corresponding medium flow channel. A third step surface is formed at the connection between the third segment and the corresponding medium flow channel. A limiting groove is formed between the third step surface and the inner wall of the third segment. The end of the valve seat away from the flow-blocking member extends into the third segment. The third step surface is used to limit the movement distance of the valve seat.

[0019] Furthermore, each of the preload bolts includes a head and a rod segment connected in sequence, the rod segment of each preload bolt extending out after passing through any one of the through holes and threadedly connected to a threaded hole on the second step surface.

[0020] Furthermore, each of the two valve seats has a first inclined surface on its opposite surface, and the two first inclined surfaces form an inverted V-shaped cavity. The gate plate has a second inclined surface on each side that cooperates with the two first inclined surfaces. The bottom of the valve cavity passes through the bottom of the two medium flow channels and extends into the inner layer of the valve body, and the extended part is available for the gate plate to move.

[0021] The beneficial effects of this invention are as follows: The valve seat inside the valve of this invention is installed on the inner wall of the valve cavity of the valve body by a number of pre-tightening bolts, and an elastic sealing element is provided between the valve seat and the inner wall of the valve cavity of the valve body. The pre-tightening bolts clamp the valve seat and the valve body to the elastic sealing element, thereby achieving an initial seal between the valve seat and the valve body. When the valve is closed, the valve seat further presses the elastic sealing element against the inner wall of the valve cavity of the valve body under the thrust of the flow-blocking element and / or the medium, thereby improving the sealing performance between the valve seat and the valve body when the valve is closed. The higher the pressure, the greater the sealing pressure and the better the sealing effect. It can be used in high temperature and high pressure environments and has high sealing reliability. At the same time, it can also achieve the purpose of disassembly, thereby solving the problem that existing floating valve seat structures and welded valve seat structures cannot simultaneously meet the requirements of disassembly and a wide applicable temperature range, thus improving the overall service life of the valve.

[0022] The first step surface of the mounting groove and the first conical surface of the valve seat are provided such that the first conical surface is provided on the side wall of the valve seat near the sealing groove. The first conical surface is inclined from the inside to the outside in the direction away from the first step surface, so that the valve seat can move into the mounting groove under the thrust of the flow cut-off element and / or the medium, thereby making the first conical surface of the valve seat and the second conical surface of the sealing ring fit closer together. The cooperation and pressing of the two conical surfaces greatly improves the tightness between the sealing ring and the valve seat and valve body, thereby improving the sealing performance between the valve seat and the valve body.

[0023] The first section and the second step surface of the mounting groove are designed so that the surface of the second step surface opposite the boss of the valve seat is a plane, which makes it easy to process the threaded hole, and at the same time avoids the problem of interference between the valve cavity wall and the boss, which would affect the movement of the valve seat.

[0024] The second step surface of the mounting groove allows the preload bolt to pass through the boss of the valve seat and be screwed onto the second step surface. The boss of the valve seat has several through holes evenly distributed. The preload bolt passes through the through holes on the boss and engages with the threaded holes on the second step surface. The through hole part of the valve seat can slide on the preload bolt. Thus, the tightness between the valve seat and the sealing ring and the second step surface can be adjusted by the flow cut-off element or the medium to improve the sealing performance between the valve seat and the mounting groove.

[0025] The third step of the mounting groove allows the valve seat to be limited at the end away from the flow cut-off element, while also preventing the valve seat from being squeezed by the sealing ring under the push of the flow cut-off element or the medium, thus avoiding excessive compression and damage to the sealing ring. Attached Figure Description

[0026] To more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a cross-sectional view of a valve with a replaceable valve seat according to an embodiment of the present invention;

[0028] Figure 2 This is an enlarged view (A) of a valve with a replaceable valve seat according to an embodiment of the present invention;

[0029] Figure 3 This is an exploded view of the valve seat and sealing ring of a valve with a replaceable valve seat according to an embodiment of the present invention.

[0030] Figure 4 This is a structural diagram of the preload bolt of a valve with a replaceable valve seat according to an embodiment of the present invention;

[0031] In the figure: 1-valve body, 2-valve seat, 3-elastic seal, 4-stopping element, 5-mounting groove, 8-preload bolt, 11-inlet flow channel, 12-valve cavity, 13-threaded hole, 14-outlet flow channel, 21-bore, 22-through hole, 23-first conical surface, 24-first inclined surface, 31-second conical surface, 41-second inclined surface, 51-second step surface, 52-first step surface, 53-third step surface, 81-head, 82-rod segment. Detailed Implementation

[0032] The technical solutions in the embodiments of the invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] The following will describe a specific embodiment of the present invention and its accompanying drawings. Figure 1-4The present invention discloses a valve with a replaceable valve seat, comprising a valve body 1, a valve seat 2, and a flow-stopping element 4. The valve body 1 has a valve cavity 12. The valve seat 2 is installed in the valve cavity 12 and an elastic sealing element 3 is provided between the valve seat 2 and the inner wall of the valve cavity 12. Several pre-tightening bolts 8 are passed through the valve seat 2 and are screwed onto the inner wall of the valve cavity 12 of the valve body 1, so that the valve seat 2 presses the elastic sealing element 3 against the inner wall of the valve cavity 12 of the valve body 1. When the flow-stopping element 4 closes the valve, the valve seat 2 further presses the elastic sealing element 3 against the inner wall of the valve cavity 12 of the valve body 1 under the thrust of the flow-stopping element 4 or the medium.

[0034] In this embodiment, the valve is a gate valve, the shut-off element 4 is the gate plate in the gate valve, the gate valve is provided with two valve seats 2, each valve seat 2 has several through holes 22 evenly distributed on its edge, the inner wall of the valve cavity 12 is provided with several threaded holes 13 that correspond one-to-one with several through holes 22, and each valve seat 2 is provided with a pre-tightening bolt 8, which is screwed into the threaded hole 13 after passing through the through hole 22.

[0035] The preload bolt 8 is used to provide initial preload force for the elastic seal 3, and the initial seal between the valve seat 2 and the valve body 1 is achieved by tightening.

[0036] The valve seat 2 inside the valve is installed on the inner wall of the valve cavity 12 of the valve body 1 by several pre-tightening bolts 8. An elastic sealing element 3 is provided between the valve seat 2 and the inner wall of the valve cavity 12 of the valve body 1. The valve seat 2 and the valve body 1 are clamped together by the pre-tightening bolts 8 to achieve the initial seal between the valve seat 2 and the valve body 1. When the valve is closed, the valve seat 2 further presses the elastic sealing element 3 against the inner wall of the valve cavity 12 of the valve body 1 under the thrust of the flow cut-off element 4 and / or the medium, so as to improve the sealing performance between the valve seat 2 and the valve body 1 when the valve is closed. The higher the pressure, the greater the sealing pressure and the better the sealing effect. It can be used in high temperature and high pressure environments and has high sealing reliability. At the same time, it can also achieve the purpose of disassembly, so as to solve the problem that the existing floating valve seat structure and welded valve seat structure cannot simultaneously meet the requirements of disassembly and wide applicable temperature range, thus improving the overall service life of the valve.

[0037] In this embodiment, the pre-tightening bolt 8 can be fixed to the inner wall of the valve cavity 12 of the valve body 1 or the second step surface 51 by spot welding to prevent the pre-tightening bolt 8 from falling off during operation.

[0038] The valve body 1 is provided with two medium flow channels that are respectively connected to the valve cavity 12. One medium flow channel is the inlet flow channel 11, and the other medium flow channel is the outlet flow channel 14.

[0039] In this embodiment, the valve is a gate valve, and the valve body 1 has mounting grooves 5 on the inner wall at the intersection of the inlet flow channel 11 and the outlet flow channel 14 with the valve cavity 12, and a valve seat 2 is installed in each of the two mounting grooves 5.

[0040] In other embodiments, the valve can be a check valve. The valve body 1 has an installation groove 5 on the inner wall at the intersection of the inlet flow channel 11 and the valve cavity 12. The throttling element 4 is the valve disc in the check valve. At this time, the end of the valve seat 2 away from the throttling element 4 is installed in the installation groove of the inlet flow channel 11, and the number of valve seats 2 is one.

[0041] The number of valve seats 2 is the same as the number of mounting slots 5, and one end of the valve seat 2 is installed in the corresponding mounting slot 5.

[0042] The valve body 1 has mounting grooves 5 on the inner wall at the intersection of the inlet flow channel 11 and the outlet flow channel 14 with the valve cavity 12.

[0043] Under operating conditions, the higher the pressure, the greater the sealing pressure of the elastic sealing element 3 of valve seat 2, the better the sealing effect, the higher the applicable pressure, and the higher the sealing reliability.

[0044] The mounting groove 5 has a first section, a second section and a third section arranged sequentially in the direction away from the interceptor 4. The inner diameter of the third section is smaller than the inner diameter of the second section. The connection between the third section and the second section forms a first stepped surface 52. A sealing groove is formed between the first stepped surface 52 and the hole wall of the second section. An elastic seal 3 is disposed in the sealing groove, and both ends of the elastic seal 3 abut against the first stepped surface 52 and the valve seat 2, respectively.

[0045] The valve seat 2 has a first conical surface 23 on the side wall near the sealing groove. The first conical surface 23 is inclined from the inside to the outside in the direction away from the first step surface 52. The elastic sealing element 3 is a sealing ring, and the sealing ring has a second conical surface 31 that fits and conforms to the first conical surface 23.

[0046] The surface roughness Ra of at least the portion of the sealing groove in the mounting groove 5 that contacts the sealing ring is not less than 1.6 μm.

[0047] The first step surface 52 of the mounting groove 5 and the first conical surface 23 of the valve seat 2 are provided such that the first conical surface 23 is provided on the side wall of the outer wall of the valve seat 2 near the sealing groove. The first conical surface 23 is inclined from the inside to the outside in the direction away from the first step surface 52, so that the valve seat 2 can move into the mounting groove 5 under the thrust of the flow cut-off element and / or the medium, thereby making the first conical surface 23 of the valve seat 2 and the second conical surface 31 of the sealing ring even tighter. The cooperation and pressing of the two conical surfaces greatly improves the tightness between the sealing ring and the valve seat 2, and at the same time improves the sealing performance of the valve.

[0048] The sealing ring is made of flexible graphite or flexible metal. The longitudinal section of the sealing ring is a trapezoidal or planar rectangular structure with an inclined surface, preferably a trapezoidal structure with an inclined surface to improve the sealing effect. That is, the sealing ring is provided with a second conical surface 31 that fits and conforms to the first conical surface 23.

[0049] A boss 21 is provided on the outer wall of the valve seat 2, and several through holes 22 are evenly distributed on the edge of the boss 21;

[0050] Each preload bolt 8 includes a head 81 and a rod segment 82 connected in sequence. The rod segment 82 of each preload bolt 8 extends out after passing through any one of the through holes 22 and is threadedly connected to the threaded hole 13 on the second stepped surface 51.

[0051] The mounting groove 5 has a first section, a second section, and a third section arranged sequentially in a direction away from the flow-blocking member 4. The inner diameter of the second section is smaller than the inner diameter of the first section, and a second stepped surface 51 is formed at the connection between the second section and the first section.

[0052] The second step surface 51 is used to avoid the boss 21 of the valve seat 2, and several threaded holes 13 are opened on the second step surface 51 along the circumferential direction of the circular groove.

[0053] The first section and the second step surface 51 of the mounting groove 5 are set so that the surface of the second step surface 52 opposite to the boss 21 of the valve seat 2 is a plane, which makes it easy to process the threaded hole 13, and at the same time avoids the problem of interference between the wall of the valve cavity 12 and the boss 21, which would affect the movement of the valve seat 2.

[0054] The second step surface 51 of the mounting groove 5 allows the pre-tightening bolt 8 to pass through the boss 21 of the valve seat 2 and be screwed onto the second step surface 51. The boss 21 of the valve seat 2 has several through holes 22 evenly distributed on it. The pre-tightening bolt 8 passes through the through holes 22 on the boss 21 and is screwed onto the threaded hole 13 on the second step surface 51. The through hole 22 of the valve seat 2 can slide on the pre-tightening bolt 8. Thus, the tightness between the valve seat 2 and the sealing ring and the second step surface 51 can be adjusted by the flow cut-off element 4 or the medium, thereby improving the sealing performance between the valve seat 2 and the mounting groove 5.

[0055] The inner diameter of the third section is larger than the inner diameter of the corresponding medium flow channel. The connection between the third section and the corresponding medium flow channel forms a third step surface 53. The third step surface 53 and the inner wall of the third section form a limiting groove. The end of the valve seat 2 away from the flow cut-off member 4 extends into the third section. The third step surface 53 is used to limit the movement distance of the valve seat 2.

[0056] The third step surface 53 of the mounting groove 5 can limit the valve seat 2 away from the flow cut-off element 4 through the third step surface 53. At the same time, it can also ensure that the valve seat 2 is squeezed by the sealing ring under the push of the flow cut-off element 4 or the medium, so that the sealing ring is not detached from the mounting groove 5 or the flow cut-off element 4 falls into the bottom of the valve cavity 12 due to excessive descent.

[0057] The two valve seats 2 are provided with a first inclined surface 24 on their opposite surfaces. The two first inclined surfaces 24 form an inverted V-shaped cavity. The gate is provided with a second inclined surface 41 on both sides that cooperates with the two first inclined surfaces 24. The bottom of the valve cavity 12 passes through the bottom of the inlet flow channel 11 and the outlet flow channel 14 and extends into the inner layer of the valve body 1. The extended part can be used for the gate to move.

[0058] The workflow of this invention:

[0059] Valve seat installation process:

[0060] The elastic sealing element 3 of each valve seat 2 is placed in the sealing groove formed between the first step surface 52 of the mounting groove 5 and the inner wall of the circular groove. The end of each valve seat 2 away from the first inclined surface 24 is installed in the mounting groove 5, and its end extends into the limiting groove after passing through the sealing groove, with a reserved gap between it and the third step surface 53 of the limiting groove. At this time, the first conical surface 23 on the outer wall of each valve seat 2 fits with the second conical surface 31 of the sealing ring. Several pre-tightening bolts 8 are passed through the through hole 22 on the boss 21 on the outer wall of each valve seat 2 and extend out, and are threadedly connected to the threaded hole 13 on the second step surface 51 until the head 81 of the pre-tightening bolts 8 presses the valve seat 2 onto the valve body 1. The pre-tightening bolts 8 are then spot-welded to the second step surface 51 for fixation. At this time, each valve seat 2 has a certain gap with the second step surface 51 of the two mounting grooves 5, and a reserved gap with the third step surface 53 of the limiting groove. The valve seat 2 is then installed.

[0061] The valve sealing process:

[0062] When the valve is closed, the shut-off element 4 (i.e., the gate of the gate valve, the valve disc of the check valve) cuts off the inlet flow passage 11 and the outlet flow passage 14.

[0063] When the gate valve is shut off, under the downward driving force, the second inclined surface 41 on both sides of the gate pushes the first inclined surface 24 on the opposite surface of the two valve seats 2 to move towards the inlet flow channel 11 and outlet flow channel 14 of the gate valve on both sides. The further the gate moves down, the two valve seats 2 move towards the inlet flow channel 11 and outlet flow channel 14 of the gate valve along the corresponding pre-tightening bolts 8, further pressing the elastic sealing element 3 against the inner wall of the valve cavity 12 of the valve body 1, so as to improve the sealing performance between the valve cavity 12 of the valve body 1 and the valve seat 2. When the valve seat 2 is worn, the gate can continue to move downward to ensure the sealing effect between the valve seat 2 and the valve plate.

[0064] When the check valve is shut off, the valve disc fits against the first inclined surface 24 of the valve seat 2. Under the back pressure of the medium, the valve seat 2 continues to move along the pre-tightening bolt 8 toward the inlet of the check valve, which further presses the elastic sealing element 3 against the inner wall of the valve cavity 12 of the valve body 1, thereby improving the sealing between the valve cavity 12 of the valve body 1 and the valve seat 2.

[0065] The valve seat structure of the valve in this invention has strong applicability and can be applied to various types of valves. It can also simultaneously meet the two performance requirements of being detachable and having a wide applicable temperature range.

[0066] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A valve with a replaceable valve seat, characterized in that, The valve includes a valve body (1), a valve seat (2), and a flow-stopping element (4). The valve body (1) has a valve cavity (12). The valve seat (2) is installed in the valve cavity (12) and has an elastic sealing element (3) between it and the inner wall of the valve cavity (12). Several pre-tightening bolts (8) are passed through the valve seat (2). The several pre-tightening bolts (8) are screwed onto the inner wall of the valve cavity (12) of the valve body (1) so that the valve seat (2) presses the elastic sealing element (3) against the inner wall of the valve cavity (12) of the valve body (1). When the shut-off element (4) closes the valve, the valve seat (2) further presses the elastic seal (3) against the inner wall of the valve cavity (12) of the valve body (1) under the thrust of the shut-off element (4) or the medium; The valve body (1) is provided with two medium flow channels that are respectively connected to the valve cavity (12). An installation groove (5) is provided on the inner wall of one of the medium flow channels of the valve body (1) where it intersects with the valve cavity (12), or the installation groove (5) is provided on the inner wall of the two medium flow channels of the valve body (1) where they intersect with the valve cavity (12). The number of valve seats (2) is the same as the number of mounting slots (5), and one end of the valve seat (2) is installed in the corresponding mounting slot (5); The mounting groove (5) has a second section and a third section arranged sequentially in a direction away from the interceptor (4). The inner diameter of the third section is smaller than the inner diameter of the second section. A first stepped surface (52) is formed at the connection between the third section and the second section. A sealing groove is formed between the first stepped surface (52) and the hole wall of the second section. The elastic seal (3) is disposed in the sealing groove, and both ends of the elastic seal (3) abut against the first stepped surface (52) and the valve seat (2) respectively. The valve seat (2) has a first conical surface (23) on the side wall near the sealing groove. The first conical surface (23) is inclined from the inside to the outside in a direction away from the first step surface (52). The elastic sealing element (3) is a sealing ring, and the sealing ring has a second conical surface (31) that fits and conforms to the first conical surface (23).

2. The valve with a replaceable valve seat according to claim 1, characterized in that, The mounting grooves (5) are respectively provided on the inner wall of the two medium flow channels of the valve body (1) where they intersect with the valve cavity (12). The valve is a gate valve, and the shut-off component (4) is the gate plate in the gate valve. The gate valve is provided with two valve seats (2). Each valve seat (2) has several through holes (22) evenly distributed on its edge. The inner wall of the valve cavity (12) is provided with several threaded holes (13) that correspond one-to-one with several through holes (22). Each valve seat (2) is provided with a pre-tightening bolt (8). The pre-tightening bolt (8) passes through the through hole (22) and is screwed into the threaded hole (13).

3. The valve with a replaceable valve seat according to claim 1, characterized in that, The sealing ring is made of flexible graphite or flexible metal.

4. The valve with a replaceable valve seat according to claim 1, characterized in that, The valve seat (2) has a boss (21) on its outer wall, and the edge of the boss (21) has a plurality of through holes (22) evenly distributed. The mounting groove (5) has a first section, a second section, and a third section arranged sequentially in a direction away from the interceptor (4). The inner diameter of the second section is smaller than the inner diameter of the first section, and a second stepped surface (51) is formed at the connection between the second section and the first section. The second step surface (51) is used to avoid the boss (21) of the valve seat (2), and a number of threaded holes (13) are opened on the second step surface (51) along the circumferential direction of the mounting groove (5).

5. A valve with a replaceable valve seat according to claim 1, characterized in that, The inner diameter of the third segment is larger than the inner diameter of the corresponding medium flow channel. A third step surface (53) is formed at the connection between the third segment and the corresponding medium flow channel. A limiting groove is formed between the third step surface (53) and the inner wall of the third segment. The end of the valve seat (2) away from the flow cut-off member (4) extends into the third segment. The third step surface (53) is used to limit the movement distance of the valve seat (2).

6. A valve with a replaceable valve seat according to claim 4, characterized in that, Each of the preload bolts (8) includes a head (81) and a rod segment (82) connected in sequence. The rod segment (82) of each preload bolt (8) extends out after passing through any of the through holes (22) and is threadedly connected to a threaded hole (13) on the second stepped surface (51).

7. A valve with a replaceable valve seat according to claim 2, characterized in that, The two valve seats (2) are provided with a first inclined surface (24) on their opposite sides. The two first inclined surfaces (24) form an inverted V-shaped cavity. The gate is provided with a second inclined surface (41) on both sides that cooperates with the two first inclined surfaces (24). The bottom of the valve cavity (12) passes through the bottom of the two medium flow channels and extends into the inner layer of the valve body (1). The extended part is available for the gate to move.

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