Valve with replaceable valve seat

Abstract

The invention relates to the technical field of valve sealing, and particularly discloses a valve with a replaceable valve seat, which comprises a valve body, the valve seat and a cut-off piece, a valve cavity is arranged in the valve body, the valve seat is arranged in the valve cavity, an elastic sealing piece is arranged between the valve seat and the inner wall of the valve cavity, and a plurality of pre-tightening bolts are arranged on the valve seat in a penetrating manner; and a plurality of pre-tightening bolts are screwed on the inner wall of the valve cavity of the valve body, so that the valve seat compresses the elastic sealing element on the inner wall of the valve cavity of the valve body, and when the valve is closed by the cut-off element, the valve seat further compresses the elastic sealing element on the inner wall of the valve cavity of the valve body under the thrust of the cut-off element or a medium. According to the valve, the valve seat and the valve body clamp the elastic sealing piece through the pre-tightening bolt, initial sealing of the valve seat and the valve body is achieved, and when the valve is closed, the valve seat further presses the elastic sealing piece on the inner wall of the valve cavity of the valve body under the thrust of the closure piece and / or a medium so as to improve the sealing performance between the valve seat and the valve body; and meanwhile, the aim of dismounting can be fulfilled.

Description

Technical Field

[0001] The invention belongs to the technical field of valve sealing, in particular to a valve with a replaceable valve seat. Background Art

[0002] Gate valves are one of the most widely used valves at present. They are widely used in a wide range of industries and are applicable to a wide range of working conditions. Gate valves can be used at normal temperature and pressure, high temperature and high pressure, and low temperature (cryogenic). According to the characteristics of the working conditions, the structure and performance of gate valve products are also varied.

[0003] Normal temperature and low temperature gate valves are usually sealed with non-metallic soft materials, and the valve seat can be sealed with a floating seal relative to the valve body. Although this can facilitate the replacement of the valve seat during maintenance, it is not suitable for high temperature and high pressure conditions, and the versatility of the gate valve cannot be achieved;

[0004] As for high-temperature and high-pressure gate valves, because the valve seat has to withstand high-temperature and high-pressure working conditions, non-metallic soft materials cannot meet the working conditions. The industry basically adopts a fixed valve seat with a welded structure, and the valve seat of this structure cannot be disassembled. When the sealing performance of the valve seat is reduced, the entire gate valve will be unable to be repaired, reducing the service life of the valve. Therefore, it is urgent to design a valve with a replaceable valve seat to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a valve with a replaceable valve seat, which solves the problem that the floating valve seat proposed above can be easily replaced but cannot be used in high temperature and high pressure conditions, and the fixed valve seat structure of the welded structure cannot be disassembled, the sealing performance is reduced and it cannot be repaired.

[0006] In order to solve the above technical problems, the present invention provides a valve with a replaceable valve seat, comprising a valve body, a valve seat and a shut-off member, wherein a valve cavity is arranged in the valve body, the valve seat is installed in the valve cavity and an elastic sealing member is arranged between the valve seat and the inner wall of the valve cavity, and a plurality of pre-tightening bolts are passed through the valve seat, and the plurality of pre-tightening bolts are screwed on the inner wall of the valve cavity of the valve body, so that the valve seat presses the elastic sealing member against the inner wall of the valve cavity of the valve body.

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

[0008] Further, the valve body is provided with two medium flow channels respectively connected with the valve cavity, a mounting groove is provided on the inner wall where one of the medium flow channels of the valve body intersects with the valve cavity, or the mounting grooves are respectively provided on the inner wall where the two medium flow channels of the valve body intersect with the valve cavity;

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

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

[0011] The valve is a gate valve, the shut-off member is a gate plate in the gate valve, two valve seats are arranged in the gate valve, a plurality of through holes are evenly distributed on the edge of each valve seat, a plurality of threaded holes corresponding to the plurality of through holes are arranged on the inner wall of the valve cavity, and a pre-tightening bolt is penetrated through each valve seat, and the pre-tightening bolt is screwed into the threaded hole after passing through the through hole.

[0012] Furthermore, the mounting groove has a second section and a third section which are sequentially arranged in a direction away from the shut-off member, the inner diameter of the third section is smaller than the inner diameter of the second section, a first step surface is formed at the connection between the third section and the second section, a sealing groove is formed between the first step surface and the hole wall of the second section, the elastic sealing member is arranged in the sealing groove, and the two ends of the elastic sealing member are respectively abutted against the first step surface and the valve seat.

[0013] Furthermore, a first conical surface is provided on the side wall of the valve seat close to the sealing groove, and the first conical surface is inclined from the inside to the outside in a direction away from the first step surface. The elastic sealing component is a sealing ring, and the sealing ring is provided with a second conical surface that cooperates with the first conical surface.

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

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

[0016] The mounting groove comprises a first section, a second section and a third section which are sequentially arranged in a direction away from the shut-off member, the inner diameter of the second section is smaller than the inner diameter of the first section, and a second step surface is formed at a connection between the second section and the first section.

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

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

[0019] Furthermore, each of the pre-tightening bolts includes a head and a rod section which are connected in sequence, and the rod section of each of the pre-tightening bolts extends out after passing through any one of the through holes and is threadedly connected to the threaded hole on the second step surface.

[0020] Furthermore, the opposing surfaces of the two valve seats are each provided with a first inclined surface, the two first inclined surfaces form an inverted eight-shaped cavity, and second inclined surfaces cooperating with the two first inclined surfaces are respectively provided on both sides of the gate plate, 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 can allow the gate plate to move.

[0021] The beneficial effects of the present invention are as follows: the valve seat in the valve of the present invention is installed on the inner wall of the valve cavity of the valve body by a plurality of pre-tightening bolts, and an elastic sealing member is arranged between the valve seat and the inner wall of the valve cavity of the valve body, and the valve seat and the valve body are clamped with the elastic sealing member by the pre-tightening bolts to realize the initial sealing between the valve seat and the valve body; when the valve is closed, the valve seat further presses the elastic sealing member on the inner wall of the valve cavity of the valve body under the thrust of the shut-off member and / or the medium, so as to improve the sealing performance between the valve seat and the valve body when the valve is closed, and the higher the pressure, the greater the sealing pressure, the better the sealing effect, and the valve can be applied to high temperature and high pressure environment, and the sealing reliability is high, and the purpose of disassembly can also be achieved, so as to solve the problem that the existing floating valve seat structure and the assembly welded valve seat structure cannot simultaneously meet the effects of disassembly and wide applicable temperature range, thereby 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 arranged so that the first conical surface is arranged on the side wall of the outer wall of the valve seat close to the sealing groove, and the first conical surface is arranged to be inclined from the inside to the outside in a direction away from the first step surface, so that the valve seat can move into the mounting groove under the thrust of the shut-off member and / or the medium, so that the first conical surface of the valve seat and the second conical surface of the sealing ring are further pressed together, and the cooperation and pressing of the two conical surfaces greatly improves the tightness between the sealing ring and the valve seat and the valve body, thereby improving the sealing between the valve seat and the valve body;

[0023] The arrangement of the first section of the mounting groove and the second step surface makes the surface of the second step surface opposite to the boss of the valve seat a plane, which is easy to process the threaded hole and avoids the problem of interference between the valve cavity wall and the boss to affect the movement of the valve seat;

[0024] The second step surface of the mounting groove is provided so that the pre-tightening bolt can pass through the boss of the valve seat and be screwed on the second step surface, and the boss of the valve seat is evenly distributed with a plurality of through holes, the pre-tightening bolt passes through the through holes on the boss and is screwed into the threaded holes on the second step surface, and the through hole portion of the valve seat can slide on the pre-tightening bolt, so that the tightness between the valve seat and the sealing ring and the second step surface can be adjusted through the shut-off piece or the medium, so as to improve the sealing performance between the valve seat and the mounting groove;

[0025] The setting of the third step surface of the mounting groove allows the end of the valve seat away from the shut-off member to be limited by the third step surface, and also ensures that the valve seat is squeezed against the sealing ring under the push of the shut-off member or the medium, thereby preventing the sealing ring from being excessively squeezed and damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0028] Figure 2 It is an enlarged view of A of a valve with a replaceable valve seat in an embodiment of the present invention;

[0029] Figure 3 It is an exploded view of a valve seat and a sealing ring of a valve with a replaceable valve seat in an embodiment of the present invention;

[0030] Figure 4 It is a structural diagram of a pre-tightening bolt of a valve with a replaceable valve seat in an embodiment of the present invention;

[0031] In the figure: 1-valve body, 2-valve seat, 3-elastic sealing member, 4-shut-off member, 5-mounting groove, 8-pre-tightening bolt, 11-inlet flow channel, 12-valve cavity, 13-threaded hole, 14-outlet flow channel, 21-boss, 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 section. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings of the present invention specification to clearly and completely describe the technical solutions in the embodiments of the 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The following will be combined with a specific embodiment of the present invention and the attached Figure 1-4In detail, a valve with a replaceable valve seat is specifically disclosed, comprising a valve body 1, a valve seat 2 and a shut-off member 4, wherein a valve cavity 12 is arranged in the valve body 1, the valve seat 2 is installed in the valve cavity 12 and an elastic sealing member 3 is arranged between the valve seat 2 and the inner wall of the valve cavity 12, a plurality of pre-tightening bolts 8 are penetrated through the valve seat 2, and the plurality of pre-tightening bolts 8 are screwed on the inner wall of the valve cavity 12 of the valve body 1, so that the valve seat 2 presses the elastic sealing member 3 against the inner wall of the valve cavity 12 of the valve body 1, and when the shut-off member 4 closes the valve, the valve seat 2 further presses the elastic sealing member 3 against the inner wall of the valve cavity 12 of the valve body 1 under the thrust of the shut-off member 4 or the medium;

[0034] In this embodiment, the valve is a gate valve, the shut-off member 4 is a gate plate in the gate valve, two valve seats 2 are arranged in the gate valve, a plurality of through holes 22 are evenly distributed on the edge of each valve seat 2, a plurality of threaded holes 13 corresponding to the plurality of through holes 22 are arranged on the inner wall of the valve cavity 12, and a pre-tightening bolt 8 is penetrated on each valve seat 2, and the pre-tightening bolt 8 passes through the through hole 22 and is screwed into the threaded hole 13.

[0035] The pre-tightening bolt 8 is used to provide an initial pre-tightening force for the elastic seal 3, and achieves the initial sealing between the valve seat 2 and the valve body 1 by tightening;

[0036] The valve seat 2 in the valve is installed on the inner wall of the valve cavity 12 of the valve body 1 by a plurality of pre-tightening bolts 8, and an elastic sealing member 3 is provided between the valve seat 2 and the inner wall of the valve cavity 12 of the valve body 1, and the valve seat 2 and the valve body 1 are clamped with the elastic sealing member 3 by the pre-tightening bolts 8 to realize the initial sealing of the valve seat 2 and the valve body 1; when the valve is closed, the valve seat 2 further presses the elastic sealing member 3 against the inner wall of the valve cavity 12 of the valve body 1 under the thrust of the shut-off member 4 and / or the medium to improve the sealing between the valve seat 2 and the valve body 1 when the valve is closed, and the higher the pressure, the greater the sealing pressure, the better the sealing effect, and it can be applied to high temperature and high pressure environment, and has high sealing reliability, and can also achieve the purpose of disassembly, so as to solve the problem that the existing floating valve seat structure and the assembled welded valve seat structure cannot simultaneously meet the effects of disassembly and a wide applicable temperature range, thereby 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] Two medium flow channels are provided in the valve body 1 and are respectively connected to the valve cavity 12, one of which is an inlet flow channel 11 and the other is an outlet flow channel 14;

[0039] In this embodiment, the valve is a gate valve, and the valve body 1 is provided with mounting grooves 5 on the inner wall where the inlet flow channel 11 and the outlet flow channel 14 intersect 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, and a mounting groove 5 is provided on the inner wall of the valve body 1 at the intersection of the inlet flow channel 11 and the valve cavity 12, and the shut-off member 4 is a valve disc in the check valve. At this time, the end of the valve seat 2 away from the shut-off member 4 is installed in the mounting groove of the inlet flow channel 11, and the number of valve seats 2 is one.

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

[0042] The valve body 1 is provided with a mounting groove 5 on the inner wall where the inlet flow channel 11 and the outlet flow channel 14 intersect with the valve cavity 12.

[0043] Under working conditions, the elastic sealing member 3 of the valve seat 2 has a higher sealing pressure and a better sealing effect when the pressure is higher. The applicable pressure is high and the sealing reliability is high.

[0044] The mounting groove 5 comprises a first section, a second section and a third section which are sequentially arranged in a direction away from the shut-off member 4. The inner diameter of the third section is smaller than the inner diameter of the second section. A first step surface 52 is formed at the connection between the third section and the second section. A sealing groove is formed between the first step surface 52 and the hole wall of the second section. The elastic sealing member 3 is arranged in the sealing groove, and two ends of the elastic sealing member 3 are respectively against the first step surface 52 and the valve seat 2.

[0045] A first conical surface 23 is provided on the side wall of the valve seat 2 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 member 3 is a sealing ring, and a second conical surface 31 is provided on the sealing ring to fit with the first conical surface 23.

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

[0047] The arrangement of the first step surface 52 of the mounting groove 5 and the first conical surface 23 of the valve seat 2 enables the first conical surface 23 to be provided on the side wall of the outer wall of the valve seat 2 close to 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, so that the valve seat 2 can move into the mounting groove 5 under the thrust of the shut-off member and / or the medium, thereby making the first conical surface 23 of the valve seat 2 further close to the second conical surface 31 of the sealing ring. The cooperation and compression 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, and the longitudinal section of the sealing ring is a trapezoid with an inclined surface or a flat rectangular structure, preferably a trapezoid with an inclined surface to improve the sealing effect, that is, the sealing ring is provided with a second cone surface 31 that cooperates with the first cone surface 23.

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

[0050] Each pre-tightening bolt 8 includes a head 81 and a rod section 82 which are connected in sequence. The rod section 82 of each pre-tightening bolt 8 extends out after passing through any through hole 22 and is threadedly connected to the threaded hole 13 on the second step surface 51 .

[0051] The mounting groove 5 comprises a first section, a second section and a third section which are sequentially arranged in a direction away from the shut-off member 4. The inner diameter of the second section is smaller than the inner diameter of the first section. A second step 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 a plurality of threaded holes 13 are opened on the second step surface 51 along the circumferential direction of the circular groove.

[0053] The first section of the mounting groove 5 and the second step surface 51 are arranged so that the surface of the second step surface 52 opposite to the boss 21 of the valve seat 2 is a plane, which facilitates the processing of the threaded hole 13 and avoids the problem that the wall of the valve cavity 12 and the boss 21 interfere with each other and affect the movement of the valve seat 2.

[0054] The second step surface 51 of the mounting groove 5 is provided so that the pre-tightening bolt 8 can pass through the boss 21 of the valve seat 2 and be screwed on the second step surface 51. The boss 21 of the valve seat 2 is evenly provided with a plurality of through holes 22. The pre-tightening bolt 8 passes through the through hole 22 on the boss 21 and is screwed with 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 through the shut-off member 4 or the medium, so as to improve 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. A third step surface 53 is formed at the connection between the third section and the corresponding medium flow channel. A limiting groove is formed between the third step surface 53 and the inner wall of the third section. One end of the valve seat 2 away from the shut-off member 4 extends into the third section. The third step surface 53 is used to limit the moving distance of the valve seat 2.

[0056] The setting of the third step surface 53 of the mounting groove 5 can limit the end of the valve seat 2 away from the shut-off member 4 through the third step surface 53, and can also ensure that the valve seat 2 is squeezed against the sealing ring under the push of the shut-off member 4 or the medium, causing the sealing ring to detach from the mounting groove 5 or the shut-off member 4 to drop excessively into the bottom of the valve chamber 12.

[0057] The opposite surfaces of the two valve seats 2 are each provided with a first inclined surface 24, and the two first inclined surfaces 24 form an inverted eight-shaped cavity. Second inclined surfaces 41 cooperating with the two first inclined surfaces 24 are respectively provided on both sides of the gate plate. 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 to the inner layer of the valve body 1, and the extended part can provide for the movement of the gate plate.

[0058] The workflow of the present invention is:

[0059] Valve seat installation process:

[0060] The elastic sealing member 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, and one end of each valve seat 2 away from the first inclined surface 24 is installed in the mounting groove 5, and its end passes through the sealing groove and extends into the limiting groove, and there is a reserved gap with 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, and a plurality of pre-tightening bolts 8 are extended through the through holes 22 on the boss 21 on the outer wall of each valve seat 2, and are threadedly connected with the threaded holes 13 on the second step surface 51 until the head 81 of the pre-tightening bolt 8 presses the valve seat 2 onto the valve body 1, and the pre-tightening bolt 8 is spot-welded to the second step surface 51. At this time, there is a certain gap between each valve seat 2 and the second step surfaces 51 of the two mounting grooves 5, and there is a reserved gap with the third step surface 53 of the limiting groove, and the valve seat 2 is installed.

[0061] Valve sealing process:

[0062] When the valve is closed, the shutoff member 4 (i.e., the gate of the gate valve, the valve disc of the check valve) cuts off the inlet flow channel 11 and the outlet flow channel 14.

[0063] When the gate valve is cut off, the gate plate is driven downward, and the second inclined surfaces 41 on both sides thereof push the first inclined surfaces 24 on the opposite surfaces of the two valve seats 2 to move toward the inlet flow channel 11 and the outlet flow channel 14 of the gate valves on both sides. The further the gate plate goes downward, the two valve seats 2 move toward the inlet flow channel 11 and the outlet flow channel 14 of the gate valve along the corresponding pre-tightening bolts 8, further pressing the elastic sealing member 3 against the inner wall of the valve cavity 12 of the valve body 1 to improve the sealing between the valve cavity 12 of the valve body 1 and the valve seat 2. When the valve seat 2 is worn, the gate plate 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 cut off, the valve disc fits against the first inclined surface 24 of the valve seat 2. Under the recoil force of the medium, the valve seat 2 continues to move along the pre-tightening bolt 8 toward the inlet of the check valve, further pressing the elastic seal 3 against the inner wall of the valve cavity 12 of the valve body 1 to improve 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 the present invention has strong applicability, can be applied to various types of valves, and can also simultaneously meet the two properties of being detachable and applicable to a wide temperature range.

[0066] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to 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 invention comprises a valve body (1), a valve seat (2) and a shut-off member (4); the valve body (1) is provided with a valve cavity (12); the valve seat (2) is installed in the valve cavity (12) and an elastic sealing member (3) is provided between the valve seat (2) and the inner wall of the valve cavity (12); a plurality of pre-tightening bolts (8) are passed through the valve seat (2); the plurality of pre-tightening bolts (8) are screwed on the inner wall of the valve cavity (12) of the valve body (1), so that the valve seat (2) presses the elastic sealing member (3) against the inner wall of the valve cavity (12) of the valve body (1); When the shut-off member (4) closes the valve, the valve seat (2) further presses the elastic sealing member (3) against the inner wall of the valve cavity (12) of the valve body (1) under the thrust of the shut-off member (4) or the medium.

2. A valve with a replaceable valve seat according to claim 1, characterized in that: The valve body (1) is provided with two medium flow channels respectively connected to the valve cavity (12); a mounting groove (5) is provided on the inner wall at the intersection of one of the medium flow channels of the valve body (1) and the valve cavity (12); or the mounting grooves (5) are respectively provided on the inner wall at the intersection of the two medium flow channels of the valve body (1) and the valve cavity (12); The number of the valve seats (2) is the same as the number of the mounting grooves (5), and one end of the valve seat (2) is installed in the corresponding mounting groove (5).

3. A valve with a replaceable valve seat according to claim 2, characterized in that: The mounting grooves (5) are respectively provided on the inner walls of the intersections of the two medium flow channels of the valve body (1) and the valve cavity (12). The valve is a gate valve, the shut-off member (4) is a gate plate in the gate valve, two valve seats (2) are arranged in the gate valve, a plurality of through holes (22) are evenly distributed on the edge of each valve seat (2), a plurality of threaded holes (13) are arranged on the inner wall of the valve cavity (12) and are arranged in a one-to-one correspondence with the plurality of through holes (22), and each valve seat (2) is penetrated by a pre-tightening bolt (8), and the pre-tightening bolt (8) passes through the through hole (22) and is screwed into the threaded hole (13).

4. A valve with a replaceable valve seat according to claim 2 or 3, characterized in that: The mounting groove (5) comprises a second section and a third section which are arranged in sequence in a direction away from the shut-off member (4); the inner diameter of the third section is smaller than the inner diameter of the second section; a first step surface (52) is formed at the connection between the third section and the second section; a sealing groove is formed between the first step surface (52) and the hole wall of the second section; the elastic sealing member (3) is arranged in the sealing groove, and the two ends of the elastic sealing member (3) are respectively abutted against the first step surface (52) and the valve seat (2).

5. A valve with a replaceable valve seat according to claim 4, characterized in that: A first conical surface (23) is provided on the side wall of the valve seat (2) close to the sealing groove, and 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 member (3) is a sealing ring, and the sealing ring is provided with a second conical surface (31) that cooperates with the first conical surface (23).

6. A valve with a replaceable valve seat according to claim 5, characterized in that: The sealing ring is made of flexible graphite or flexible metal.

7. A valve with a replaceable valve seat according to claim 4, characterized in that: A boss (21) is provided on the outer wall of the valve seat (2), and a plurality of through holes (22) are evenly distributed on the edge of the boss (21). The installation groove (5) comprises a first section, a second section and a third section which are arranged in sequence in a direction away from the shut-off member (4); the inner diameter of the second section is smaller than the inner diameter of the first section; a second step 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 plurality of threaded holes (13) are opened on the second step surface (51) along the circumferential direction of the circular groove.

8. A valve with a replaceable valve seat according to claim 4, characterized in that: The inner diameter of the third section 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 section and the corresponding medium flow channel. A limiting groove is formed between the third step surface (53) and the inner wall of the third section. One end of the valve seat (2) away from the shut-off member (4) extends into the third section. The third step surface (53) is used to limit the moving distance of the valve seat (2).

9. The valve with replaceable valve seat according to claim 7, characterized in that: Each of the pre-tightening bolts (8) comprises a head (81) and a rod section (82) connected in sequence; the rod section (82) of each of the pre-tightening bolts (8) passes through any one of the through holes (22) and then extends out, and is threadedly connected to the threaded hole (13) on the second step surface (51).

10. A valve with a replaceable valve seat according to claim 3, characterized in that: The opposing surfaces of the two valve seats (2) are each provided with a first inclined surface (24), the two first inclined surfaces (24) forming an inverted eight-shaped cavity, and second inclined surfaces (41) cooperating with the two first inclined surfaces (24) are respectively provided on both sides of the gate plate, 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), and the extended portion can be used for the movement of the gate plate.

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