An on-line repairable power station gate valve

Abstract

The utility model provides an online maintenance power station gate valve, relate to gate valve structure technology, specifically disclose the valve body, gate, valve rod and valve cover, the valve body adopts integrated forging to form, all internal space adopts to complete, guarantee the service performance of valve under high temperature and high pressure, avoid the maintenance difficulty of spare part after the welding forming of valve seat and valve body, and the valve cover is together with the valve rod and the gate plate who penetrates in it, whole from the installation channel of valve body, make the maintenance personnel can screw the fixed ring exposed in the installation channel, release its to the radial constraint of half block, thereby can carry out the online maintenance replacement to valve seat, improve the replacement efficiency, and half block and fixed ring provide mechanical pressure for valve seat, ensure the sealing and fixed stability of valve seat under high pressure, make the valve seat dismounting operation simple and fast, facilitate the later maintenance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gate valve structure, in particular to an on-line inspection and repairable power station gate valve. BACKGROUND

[0002] Gate valves are widely used in many fields, and power station gate valves are mainly used in the pipelines of various systems of thermal power stations to cut off or connect the pipeline medium, and are suitable for non-corrosive media such as water and steam. The design temperature of the power station gate valve is -29-650 DEG C, the design PN is 16-800, and the nominal diameter is 3-1300 mm. Compared with other valve products, the valve used in this field has the characteristics of high temperature and high pressure resistance, and requires a self-sealing design. The higher the pressure, the more reliable the sealing. Due to the special performance and technical characteristics and working conditions, the product also has characteristics that cannot be replaced by other products.

[0003] The working condition valve requires a pressure self-tightening seal, the valve body branch pipe is welded at both ends, the valve seat and the gate plate surface require hard alloy surfacing, have good wear resistance, steam erosion resistance and scouring performance, the valve stem is subjected to corrosion-resistant nitriding treatment, and has good corrosion resistance and scratch resistance. The core technology of the pressure self-tightening seal is that the higher the pressure in the valve cavity, the more the sealing ring is extruded between the valve body and the valve cover. The sealing performance of the sealing ring determines whether the valve is leak-proof and whether it can be used normally.

[0004] The gate valve seat is generally integrally machined after surfacing with the valve body, and there are two safety hazards. First, the valve body material used under high temperature and high pressure conditions is alloy steel, and the post-welding heat treatment temperature reaches 760 DEG C. If the heat treatment is not done properly, delayed cracks may occur at the weld position, causing leakage during later use. The second problem is that the valve seat and the gate plate sealing surface may be damaged and leak due to scouring, steam erosion and other factors during long-term use. At this time, the pipeline needs to be shut down to replace or repair the valve, causing economic losses due to long-term shutdown. However, the valve seat and the valve body are usually fixedly connected by welding, which is not conducive to timely replacement in the later period. SUMMARY

[0005] The present application provides an on-line inspection and repairable power station gate valve, which can solve the problems in the background art.

[0006] The technical solution of the present application is as follows:

[0007] The present application provides an on-line inspection and repairable power station gate valve, which includes a valve body, a gate plate, a valve stem and a valve cover, a conveying channel is arranged in the valve body, and a mounting channel perpendicular to the conveying channel is formed in the outer wall of the valve body;

[0008] Two coaxial assembly grooves are formed in the inner side wall of the communication part of the conveying channel and the mounting channel, and a valve seat is embedded in each of the assembly grooves; the flashboard is rotatably arranged between the two valve seats and abuts against a sealing surface on the valve seat;

[0009] The valve cover is arranged in the mounting channel, the valve rod is connected with the flashboard after penetrating through the valve cover, the valve body is provided with a locking structure for fixing the valve cover, and a first sealing structure is arranged between the valve cover and the mounting channel;

[0010] A second sealing structure is arranged between the valve seat and the groove bottom of the assembly groove;

[0011] A plurality of arc-shaped split blocks are arranged between the assembly groove and the valve seat, and the split blocks are partially embedded in the inner side of the assembly groove; the split blocks are enclosed to form a ring structure coaxial with the valve seat, the outer side of the ring structure is provided with a fixing ring in threaded connection with the ring structure, and when the fixing ring is screwed into the outer side of the ring structure, the inner side of the fixing ring abuts against a limiting step arranged on the valve seat, and the outer side of the fixing ring abuts against the inner wall of the mounting channel to fix the valve seat in the valve body.

[0012] In some technical solutions of the present application, a positioning ring is arranged between the fixing ring and the ring structure, a mounting hole is formed in the side wall of the split block, a positioning rod is slidably arranged in the mounting hole in the vertical direction, the positioning ring is arranged on the free end of the positioning rod, a reset spring matched with the positioning rod is arranged in the mounting hole, the inner side of the fixing ring is provided with a mounting groove matched with the positioning ring, and part of the positioning ring is arranged in the limiting step arranged on the valve seat; when the fixing ring is placed on the top of the ring structure, part of the positioning ring is embedded in the mounting groove; when the fixing ring is screwed into the outer side of the ring structure, the ring structure formed by the plurality of split blocks is limited by the positioning rods and the positioning ring to be annular; when the fixing ring is screwed into a specified position of the ring structure, the positioning ring seals the gap between the fixing ring, the valve seat and the mounting channel.

[0013] In some technical solutions of the present application, the second sealing structure includes a sealing groove formed along the circle where the valve seat is arranged, and an O-shaped ring made of metal is embedded in the sealing groove.

[0014] In some technical solutions of the present application, the first sealing structure includes a sealing ring arranged between the valve cover and the mounting channel, and a pressing ring abutting against the sealing ring is embedded between the valve cover and the mounting channel.

[0015] In some technical solutions of the present application, a plurality of through grooves are formed in the outer side wall of the fixing ring in the circumferential direction.

[0016] In some technical solutions of the present application, the number of flashboard is two, and the two flashboard are detachably arranged at the end of the valve rod.

[0017] In some technical solutions of the present application, the locking structure comprises a gland mounted on the valve body, and a plurality of screw rods are arranged around the gland and are threadedly connected with the gland.

[0018] In some technical solutions of the present application, an exhaust port is formed in the side wall of the valve body, and the exhaust port is in communication with the annular region formed by the gland and the valve cover in the mounting channel.

[0019] In some technical solutions of the present application, a packing seal assembly is filled between the valve cover and the valve stem, the valve cover is provided with a gland connecting piece, the valve stem is provided with a packing gland, and the packing gland is provided with a screw rod connecting piece which is detachably connected with the gland.

[0020] In some technical solutions of the present application, a support is arranged on the valve stem, and a support frame is arranged between the support and the valve body.

[0021] Compared with the prior art, the present application has at least the following advantages or beneficial effects: the valve body is integrally forged and formed, and all internal spaces are completed by machining, thereby ensuring the service performance of the valve under high temperature and high pressure; the valve seat is gap-fitted with the valve body and is non-welded and integrated, can be replaced and maintained online, and provides mechanical compression force for the valve seat through the split blocks and the fixing ring, thereby ensuring the sealing and fixing stability of the valve seat under high pressure, and the disassembly and installation of the valve seat only need to screw the fixing ring, so that the disassembly operation of the valve seat is simple and fast. The sealing surface between the gate plate and the valve seat is the first sealing; the first sealing structure between the valve cover and the mounting channel prevents the medium from leaking from the place; the second sealing structure between the valve seat and the assembly groove prevents the medium from leaking from the back of the valve body and the sealing surface formed between the outer wall of the valve seat and the inner wall of the assembly groove, thereby constituting a complete sealing system and preventing external leakage caused by high temperature creep after long-term use. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 FIG. 1 is a front view of the sectional structure of the present application.

[0023] Figure 2 FIG. 2 is a sectional view of the present application. Figure 1 FIG. 3 is a local enlarged structure diagram of position A in FIG. 2.

[0024] Figure 3 FIG. 4 is a local enlarged structure diagram of position B in FIG. 2. Figure 1 FIG. 5 is a local enlarged structure diagram of position B in FIG. 2.

[0025] Figure 4 FIG. 6 is an installation structure diagram of the gate plate in the present application.

[0026] Figure 5 FIG. 7 is a top view of the fixing ring in the present application.

[0027] Figure 6 FIG. 8 is a combined structure diagram of the split blocks in the present application.

[0028] Figure 7 It is a top view structure schematic diagram of the valve seat in the application.

[0029] Figure 8 It is a schematic diagram of the installation structure of the positioning ring and the positioning rod in the application.

[0030] Figure 9 It is Figure 8 It is a local enlarged structure schematic diagram at C.

[0031] Reference signs: 1, valve body; 2, gate plate; 3, valve rod; 4, valve cover; 5, four split ring; 6, gland; 7, gland nut; 8, packing gland; 9, support; 10, packing seal assembly; 11, fixed ring; 12, split block; 13, O-ring; 14, valve seat; 15, sealing ring; 16, pressing ring, 17, stress deformation groove; 18, installation channel; 19, conveying channel; 20, limiting step; 21, alignment step; 22, installation groove; 23, positioning ring; 24, positioning rod; 25, reset spring; 26, sealing groove. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. The components of the embodiments of the application described and shown in the drawings can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0034] Embodiment 1

[0035] The application provides a power station gate valve which can be online inspected and repaired, like Figures 1-9 As shown in the drawings, the valve body 1, the gate plate 2, the valve rod 3 and the valve cover 4, the valve body 1 is provided with a conveying channel 19, and the outer side wall of the valve body 1 is provided with an installation channel 18 perpendicular to the conveying channel 19. The valve body 1 is integrally forged, and the internal flow channel and the space are completed by mechanical processing, so as to ensure the long-term service performance of the valve under high temperature and high pressure working conditions, and avoid the problems such as leakage caused by gaps when the valve body 1 is spliced by welding.

[0036] Two coaxial assembly grooves are formed on the inner side wall of the communication part of the conveying channel 19 and the mounting channel 18, and the valve seat 14 is embedded in each assembly groove; the shutter 2 is rotationally arranged between the two valve seats 14 and abuts against the sealing surface on the valve seat 14;

[0037] The valve cover 4 is mounted in the mounting channel 18, the valve rod 3 is connected with the shutter 2 after penetrating through the valve cover 4, the valve body 1 is provided with a locking structure for fixing the valve cover 4, and the first sealing structure is arranged between the valve cover 4 and the mounting channel 18; the valve cover 4, the valve rod 3 and the shutter 2 are designed as a module which can be integrally extracted from the side of the valve body 1, which is beneficial to the quick exposure of the core components inside the valve body 1 during maintenance, and provides a structural basis for online maintenance.

[0038] The second sealing structure is arranged between the valve seat 14 and the groove bottom of the assembly groove.

[0039] A plurality of arc-shaped split blocks 12 are arranged between the assembly groove and the valve seat 14, and the split blocks 12 are partially embedded in the inner side of the assembly groove; the split blocks 12 are enclosed to form a ring structure coaxial with the valve seat 14, and the outer side of the ring structure is provided with a fixing ring 11 which is threadedly connected with the ring structure; when the fixing ring 11 is screwed into the outer side of the ring structure, the inner side of the fixing ring 11 abuts against the limiting step 20 arranged on the valve seat 14, and the outer side of the fixing ring 11 abuts against the inner wall of the mounting channel 18 to fix the valve seat 14 in the valve body 1. The principle of fixing the valve seat 14 by the mechanical locking structure formed by the split blocks 12 and the fixing ring 11 is as follows: when the internal thread on the fixing ring 11 is screwed into the external thread ring formed by the split blocks 12, the fixing ring 11 will generate two directions of force on the ring structure: a), the radial inward force, which forces the split blocks 12 to tightly adhere to the assembly groove and the valve seat 14; b), the axial downward force, which tightly presses the valve seat 14 to the bottom of the assembly groove through the limiting step 20 of the split blocks 12 and the valve seat 14, and applies a pressing force on the second sealing structure to ensure the sealing performance. This fixing method does not need welding or complex bolt connection from the outside of the valve body 1, which reduces the risk of leakage and corrosion.

[0040] When the gate valve is installed on the pipeline, the gate plate is between the two valve seats 14 and tightly abuts against the sealing surface of the valve seat 14, so as to realize the opening or closing of the pipeline. When the internal parts such as the valve seat 14 and the gate plate need to be overhauled or replaced online, the pipeline is closed, the fixing of the valve cover 4 is released by operating the locking structure, and the valve cover 4 is taken out from the mounting channel 18 of the valve body 1 together with the valve stem 3 and the gate plate 2 penetrating through the valve cover 4. In this process, the first sealing structure is separated. The internal valve seat 14 and the fixing ring 11 are contacted by the maintenance personnel through the exposed mounting channel 18. The fixing ring 11 is rotated out by using a tool. After the fixing ring 11 is rotated out, the radial constraint of the split block 12 is released. At this time, the split block 12 can be conveniently taken out from the assembly groove. The valve seat 14 clamped by the split block 12 can be taken out from the assembly groove for replacement or maintenance. After the new valve seat 14 is installed, the split block 12 is placed in the assembly groove and surrounded to form a ring, and then the fixing ring 11 is rotated in. During the rotation-in process of the fixing ring 11, the inner side of the fixing ring 11 is pressed against the limiting step 20 of the valve seat 14, and the outer side of the fixing ring 11 abuts against the inner wall of the mounting channel 18, so that the valve seat 14 is tightly pressed and fixed in the assembly groove of the valve body 1 through the split block 12. The split block 12 and the fixing ring 11 provide the valve seat 14 with a mechanical pressing force, which ensures the sealing and fixing stability of the valve seat 14 under high pressure, and at the same time, the disassembly and installation of the valve seat 14 only need to rotate the fixing ring 11, so that the disassembly operation of the valve seat 14 is simple and fast. The sealing surface between the gate plate and the valve seat 14 is the first sealing; the first sealing structure between the valve cover 4 and the mounting channel 18 prevents the medium from leaking from the place; the second sealing structure between the valve seat 14 and the assembly groove prevents the medium from leaking from the back of the valve body 1, and the sealing surface formed between the outer wall of the valve seat 14 and the inner wall of the assembly groove constitutes a complete sealing system, which improves the sealing effect of the structure.

[0041] Preferably, the outer circle of the valve seat 14 is provided with a locating step 21, so as to facilitate the centering and calibration of the sealing surface during secondary assembly.

[0042] In some technical solutions of the present application, the second sealing structure comprises a sealing groove 26 opened along the circle where the valve seat 14 is located, and a metal O-ring 13 is embedded in the sealing groove 26. The annular sealing groove 26 is processed on the back of the valve seat 14, and the metal O-ring 13 is placed in the groove. When the valve seat 14 is tightly pressed at the bottom of the assembly groove, the metal O-ring 13 is elastically deformed, fills the micro-unevenness of the contact surface, forms a seal, and realizes static sealing by using the elastic deformation of the metal material. And using the metal O-ring 13 has higher strength, high temperature resistance and corrosion resistance than the traditional rubber or plastic O-ring 13, the rebound force provided by the metal O-ring 13 is durable and stable, and can maintain an effective sealing state for a long time.

[0043] In some technical solutions of the present application, the first sealing structure comprises a sealing ring 15 arranged around between the bonnet 4 and the mounting channel 18, and a pressing ring 16 abutting against the sealing ring 15 is further arranged between the bonnet 4 and the mounting channel 18. When the bonnet 4 is mounted into the mounting channel 18, the sealing ring 15 is first put in, and then the pressing ring 16 is used to press it tightly. The pressing ring 16 bears the pressing force from the locking structure (such as the gland 6 and the screw rod), and uniformly transmits the pressing force to the sealing ring 15, converts the axial pressing force into the radial expansion force of the sealing ring 15, so as to realize the tight sealing between the bonnet 4 and the valve body 1. Moreover, the pressing ring 16 makes the pressure distribution more uniform, avoids the local excessive wear or the sealing failure caused by the direct pressing of the gland 6 on the sealing ring 15, and prolongs the service life of the sealing ring 15.

[0044] Two annular stress deformation grooves 17 are sequentially arranged on the outer side wall of the sealing ring 15 along the axial direction thereof, the inner diameter of the sealing ring 15 on the side close to the pressing ring 16 gradually decreases away from the side of the pressing ring 16, and a tapered surface is arranged on the outer side of the bonnet 4 and cooperates with the inner wall of the sealing ring 15, so as to prevent the external leakage caused by the high temperature creep after long-term use.

[0045] In some technical solutions of the present application, a plurality of through grooves are arranged on the outer side wall of the fixing ring 11 along the circumferential direction thereof. When the fixing ring 11 is screwed, the claw part of a special tool (such as a hook wrench) is inserted into or hooked on the through groove, and the torque is applied, so that the dismounting and mounting of the fixing ring 11 in the narrow space becomes feasible and convenient. The plurality of circumferentially distributed through grooves can bear a larger torque, and the fixing ring 11 can be fully tightened or loosened.

[0046] In some technical solutions of the present application, the number of the gate plates 2 is two, and the two gate plates 2 are both detachably arranged at the end of the valve stem 3. The gate plates are connected to the end of the valve stem 3 by means of bolts, pins and the like. When maintained, the damaged gate plate can be replaced alone after the bonnet 4 module is taken out.

[0047] Preferably, the gate plate 2 is a wedge gate valve or a parallel double flat plate gate valve.

[0048] In some technical solutions of the present application, the locking structure comprises a gland 6 mounted on the valve body 1, a sink groove matched with the gland 6 is arranged on the side wall of the valve body 1, and a plurality of screw rods are arranged around the gland 6 and are screwed with the bonnet 4. The gland 6 is put into the sink groove of the valve body 1, and then the plurality of screw rods are passed through the gland 6 and are screwed into the threaded holes at the top of the bonnet 4. When the screw rods are tightened, the bonnet 4 is tightly pressed in the mounting channel 18. By means of the multi-point bolt connection, a uniform and strong axial pressing force is generated, the bonnet 4 is fixed, and the first sealing structure is pressed at the same time, so as to ensure the effective work of the first sealing structure.

[0049] In some technical solutions of the present application, an exhaust port is formed on the side wall of the valve body 1, which is in communication with the annular area formed by the gland 6, the bonnet 4 and the installation channel 18. Before opening or closing the valve, or before maintenance, the medium / gas can be injected or discharged through the exhaust port to balance the pressure of the cavity on the back of the bonnet 4, balance the pressure before and after the gate, so that the torque required to open or close the valve is greatly reduced. Before disassembling the bonnet 4, the pressure in the cavity on the back of the bonnet 4 can be released through the port to avoid the danger of operating under pressure.

[0050] In some technical solutions of the present application, the valve cover 4 and the valve stem 3 are filled with a packing seal assembly 10, the valve cover 4 is provided with a gland 6 connector, the valve stem 3 is provided with a packing gland 8, and the packing gland 8 is provided with a screw connector which is detachably connected with the gland 6. The packing seal assembly 10 is filled in the gap between the valve stem 3 and the valve cover 4. By tightening the screw connector on the packing gland 8, the packing gland 8 is pressed down, the packing is compressed, and the packing is radially expanded to tightly hold the valve stem 3, realizing sealing and dynamic sealing of the valve stem 3 during movement (opening / closing), preventing leakage of the medium along the valve stem 3. When the packing is worn out and causes leakage, the packing gland 6 can be tightened again to restore the sealing performance, without the need to replace the entire component immediately.

[0051] In some technical solutions of the present application, the valve stem 3 is provided with a bracket 9, and the bracket 9 and the valve body 1 are provided with a support frame. The bracket 9 is installed on the valve body 1 through the support frame, and the valve stem 3 passes through the bracket 9. The bracket 9 is usually provided with a driving device (such as a hand wheel, an electric actuator) of the valve, which ensures that the valve stem 3 always maintains concentricity with the valve cover 4 during movement, reduces eccentric wear, and prolongs the service life of the packing and the valve stem 3.

[0052] Example 2

[0053] Further improvement is made on the basis of the embodiment 1 of the present application, and it further comprises a positioning ring 23 installed between the fixing ring 11 and the annular structure, the side wall of each split block 12 is provided with a mounting hole, a positioning rod 24 is slidably arranged in the mounting hole in the vertical direction, the positioning ring 23 is arranged on the free end of the plurality of positioning rods 24, a reset spring 25 matched with the positioning rod 24 is arranged in the mounting hole, the inner side of the fixing ring 11 is provided with a mounting groove 22 matched with the positioning ring 23, part of the positioning ring 23 is arranged in the limiting step 20 arranged on the valve seat 14, when the fixing ring 11 is placed on the top of the annular structure, part of the positioning ring 23 is embedded in the mounting groove 22, after the fixing ring 11 is screwed into the outer side of the annular structure, the annular structure formed by the plurality of split blocks 12 is limited by the positioning rods 24 and the positioning ring 23, and when the fixing ring 11 is screwed into the specified position of the annular structure, the positioning ring 23 seals the gap between the fixing ring 11 and the valve seat 14 and the mounting channel 18. The positioning rod 24, the reset spring 25 and the positioning ring 23 constitute a guiding and positioning mechanism, which ensures that the plurality of split blocks 12 can automatically maintain the correct annular posture in the loose state, and facilitates the screwing of the fixing ring 11. The above structure solves the problem that the at least four independent split blocks 12 are difficult to align and fix, makes the assembly process smoother, improves the maintenance efficiency, prevents the split blocks 12 from being misaligned or falling off during the installation process, and improves the reliability of the entire valve seat 14 fixing system. Meanwhile, the positioning ring 23 becomes a static sealing element in the final state, after the fixing ring 11 is screwed, the positioning ring 23 is also filled in the gap between the fixing ring 11 and the limiting step 20 of the valve seat 14, plays an auxiliary sealing role, and prevents the medium from leaking from the small gap between the fixing ring 11 and the valve seat 14. Meanwhile, under the action of the reset spring 25, the positioning ring 23 can maintain close contact with the valve seat 14, provide continuous pre-tightening force, avoid the external leakage problem between the valve seat 14 and the valve body 1 caused by the high-temperature creep of the positioning ring 23, improve the service life of the structure, and improve the sealing effect.

[0054] Preferably, the positioning ring 23 is a high-temperature-resistant rubber ring or a metal ring or a sealing structure formed by the combination of the two.

[0055] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A power station gate valve capable of online inspection and maintenance, comprising a valve body (1), a gate (2), a valve stem (3), and a valve cover (4), characterized in that, The valve body (1) is provided with a conveying channel (19), and the outer side wall of the valve body (1) is provided with an installation channel (18) perpendicular to the conveying channel (19). Two coaxial assembly slots are provided on the inner side wall of the connection between the conveying channel (19) and the installation channel (18), and valve seats (14) are embedded in each of the assembly slots; the gate is rotated between the two valve seats (14) and then abuts against the sealing surface located on the valve seat (14); The valve cover (4) is installed in the installation channel (18), the valve stem (3) passes through the valve cover (4) and is connected to the gate (2), the valve body (1) is provided with a locking structure for fixing the valve cover (4), and a first sealing structure is provided between the valve cover (4) and the installation channel (18); A second sealing structure is installed between the valve seat (14) and the bottom of the assembly groove; Several arc-shaped segmented blocks (12) are provided between the assembly groove and the valve seat (14). Part of the segmented blocks (12) are embedded in the inner side of the assembly groove. After the segmented blocks (12) are enclosed, they form an annular structure coaxial with the valve seat (14). A fixing ring (11) is provided on the outer side of the annular structure and is threadedly connected to it. When the fixing ring (11) is screwed into the outer side of the annular structure, the inner side of the fixing ring (11) abuts against the limiting step (20) provided on the valve seat (14). After the outer side of the fixing ring (11) abuts against the inner wall of the installation channel (18), the valve seat (14) is fixed in the valve body (1). It also includes a positioning ring (23) installed between the fixed ring (11) and the annular structure. Each of the side walls of the segmented block (12) is provided with a mounting hole. A positioning rod (24) is slidably installed in the mounting hole along the vertical direction. The positioning ring (23) is set on the free ends of several positioning rods (24). A return spring (25) matching the positioning rod (24) is provided in the mounting hole. The inner side of the fixed ring (11) is provided with a mounting groove (22) matching the positioning ring (23). Part of the structure of the positioning ring (23) is placed on the valve seat (14). Within the limiting step (20) set above, after the fixing ring (11) is placed on the top of the annular structure, the positioning ring (23) is partially embedded in the mounting groove (22). After the fixing ring (11) is screwed into the outer side of the annular structure, it is surrounded by several segmented blocks (12) to form an annular structure that remains regular under the limiting of the positioning rod (24) and the positioning ring (23). After the fixing ring (11) is screwed into the designated position of the annular structure, the positioning ring (23) seals the gap between the fixing ring (11) and the valve seat (14) and the mounting channel (18).

2. The power station gate valve capable of online inspection and maintenance according to claim 1, characterized in that, The second sealing structure includes a sealing groove (26) opened along the circle of the valve seat (14), and an O-ring (13) made of metal is embedded in the sealing groove (26).

3. A power station gate valve capable of online inspection and maintenance according to claim 1, characterized in that, The first sealing structure includes a sealing ring (15) surrounding the valve cover (4) and the mounting channel (18). A pressure ring (16) that abuts against the sealing ring (15) is also embedded between the valve cover (4) and the mounting channel (18). Two annular stress deformation grooves (17) are sequentially provided on the outer side wall of the sealing ring (15) along its axial direction. The inner diameter of the sealing ring (15) on the side near the pressure ring (16) gradually decreases on the side away from the pressure ring (16). A conical surface that cooperates with the inner wall of the sealing ring (15) is provided on the outer side of the valve cover (4).

4. A power station gate valve capable of online inspection and maintenance according to claim 1, characterized in that, The outer wall of the fixing ring (11) has several through grooves circumferentially arranged around it.

5. A power station gate valve capable of online inspection and maintenance according to claim 1, characterized in that, The number of gates is two, and both gates can be detachably installed at the end of the valve stem (3).

6. A power station gate valve capable of online inspection and maintenance according to claim 3, characterized in that, The locking structure includes a pressure cap (6) installed on the valve body (1). A groove matching the pressure cap (6) is provided on the side wall of the valve body (1). Several screws that are threadedly connected to the valve cover (4) are arranged around the pressure cap (6). A four-ring (5) is installed between the pressure ring (16) and the pressure cap (6).

7. A power station gate valve capable of online inspection and maintenance according to claim 6, characterized in that, The valve body (1) has an exhaust port on its side wall. The exhaust port is connected to the annular area formed by the pressure cap (6) and the valve cover (4) in the installation channel (18). The outer side wall of the four-ring (5) covers the inlet of the exhaust port.

8. A power station gate valve capable of online inspection and maintenance according to claim 7, characterized in that, A packing seal assembly (10) is filled between the valve cover (4) and the valve stem (3). A pressure cap (6) connector is provided on the valve cover (4). A packing pressure cap (8) is fitted on the valve stem (3). A screw connector that is detachably connected to the pressure cap (6) is provided on the packing pressure cap (8).

9. A power station gate valve capable of online inspection and maintenance according to claim 7, characterized in that, A bracket (9) is fitted on the valve stem (3), and a support frame is provided between the bracket (9) and the valve body (1).

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