Cast steel swing check valve and using method thereof

Abstract

The invention discloses a cast steel swing check valve and a using method thereof.The cast steel swing check valve comprises a valve body, the valve body is in bolted connection with an external pipeline through flange plates A fixedly arranged at the two ends of the valve body, and a valve deck is in bolted connection with the top of the valve body and used for sealing the top of the valve body; the swing assembly is detachably installed on the position, close to the top, of the inner wall of the valve body. The replaceable wear-resistant pad is arranged on the contact surface of the valve clack and the internal channel opening of the valve body, so that the contact surface of the valve clack can be prevented from being impacted and damaged through the wear-resistant pad when the valve clack is frequently reset for a long time, the internal valve clack is prevented from being replaced, only the wear-resistant pad needs to be replaced, the later maintenance cost is reduced, and the service life of the valve clack is prolonged. And the clamping assembly is arranged in the valve body, so that the check valve can conveniently select whether the valve clack is clamped and fixed or not in different working environment requirements, and then the convenience and reliability of the check valve in use are improved.

Description

Technical Field

[0001] The invention relates to the technical field of check valve application, and in particular to a cast steel swing check valve and a use method thereof. Background Art

[0002] The opening and closing part of the swing check valve is a disc-shaped valve disc with a diameter equivalent to the pipeline. The valve disc is connected to the valve body through a rocker arm. When the medium flows downstream, the valve disc opens under the pressure of the medium. When the medium stops flowing or flows in the reverse direction, the valve disc closes under the action of its own weight and the reverse pressure of the medium, thereby preventing the medium from flowing back.

[0003] The existing cast steel swing check valve is usually used in a working environment with frequent opening and closing. During long-term opening and closing operations, the valve disc inside the valve body will continuously hit the channel opening inside the valve body, thereby causing impact damage to the valve disc contact surface, and then causing the seal at the connection between the valve disc and the internal channel opening of the valve body to be damaged, causing leakage of the internal medium, reducing the service life and economic benefit of the check valve, and being unable to flexibly limit and fix the valve disc inside the valve body. Therefore, the present invention proposes a cast steel swing check valve and a method for using the same. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a cast steel swing check valve and a method for using the same. A replaceable wear-resistant pad is provided on the contact surface between the valve disc and the internal channel opening of the valve body, so that when the valve disc is frequently reset for a long time, it can avoid impact damage to the contact surface of the valve disc through the wear-resistant pad, thereby avoiding the need to replace the internal valve disc. Only the wear-resistant pad needs to be replaced, reducing the subsequent maintenance cost. In addition, a locking assembly is provided inside the valve body, which facilitates the selection of whether the valve disc should be locked and fixed in different working environment requirements, thereby improving the convenience and reliability of the check valve in use.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide a cast steel swing check valve, including a valve body, the valve body is bolted to an external pipeline through flanges A fixedly arranged at both ends thereof, the valve cover is bolted to the top of the valve body for sealing the top of the valve body, the swing assembly is detachably mounted on the inner wall of the valve body near the top for swing sealing of the internal channel of the valve body, the clamping assembly is mounted on the side wall of the valve body near the top and can be clamped and connected with the swing assembly.

[0006] The present invention is further configured as follows: a flange B is fixedly connected to the top of the valve body, the valve cover is installed on the top of the flange B through a plurality of connecting bolts installed in a circumferential direction close to the outer wall, and a lifting ring is threadedly connected to the top of the valve cover.

[0007] Through the above technical solution, the valve cover can be installed on the top of the valve body through a plurality of connecting bolts, and the entire valve body can be conveniently lifted and moved for installation using a lifting ring.

[0008] The present invention is further configured as follows: a sealing groove is provided at the top of the inner wall of the flange B, and a sealing gasket is provided inside the sealing groove, and the bottom of the valve cover is pressed against the top of the sealing gasket.

[0009] Through the above technical solution, when the valve cover is installed, it can be sealed and connected to the top of the flange B through the sealing gasket, so as to seal the connection.

[0010] The present invention is further configured as follows: the swing assembly includes a mounting frame, the mounting frame is an inverted U-shaped configuration, and the top is arranged on the top of a fixed block fixed to the inner wall of the valve body through a mounting bolt, the bottom of the mounting bolt is rotatably connected to a swing member, a valve flap is installed near the bottom of the swing member, and a wear-resistant pad is snap-connected to one side of the valve flap.

[0011] Through the above technical solution, it is convenient to use the mounting bolts to fix the mounting frame on the fixing block, and at the same time the swing member can drive the bottom valve disc to rotate on the mounting frame, and the wear-resistant pad can protect the valve disc after reset.

[0012] The present invention is further configured as follows: a pin is fixedly provided on the top of the swing member and is rotatably connected to the bottom of the mounting frame through the pin; a mounting ring is fixedly connected to the bottom of the swing member; a counterweight block is fixedly connected to the bottom of the mounting ring; a clamping block is fixedly connected to the bottom position of the side wall of the counterweight block and is movably connected to the bottom of the locking assembly through the clamping block.

[0013] Through the above technical solution, the swing member is conveniently connected to the mounting frame through the bottom pin shaft, which is convenient for the swing operation, and the counterweight block arranged at the bottom can quickly reset the valve disc. At the same time, the valve disc can be limited and fixed by the clamping block, which facilitates the smooth flow of the internal medium and reduces the flow pressure here.

[0014] The present invention is further configured as follows: an installation shaft is fixedly connected to the center of one side of the valve disc away from the wear-resistant pad, the installation shaft passes through the installation ring, and the outer wall is sleeved with a gasket and a locking nut threadedly connected, the locking nut is pressed against the gasket, and the gasket is pressed against the installation ring.

[0015] Through the above technical solution, it is convenient to install the valve disc inside the mounting ring through the mounting shaft, and use the locking nut in conjunction with the sleeved gasket to stably fix the valve disc on the mounting ring to prevent loosening during long-term impact.

[0016] The present invention is further configured as follows: a sedimentation ring is provided on the side wall of the wear-resistant pad, and is snap-connected to the inside of a sedimentation groove opened on the side wall of the valve disc through the sedimentation ring; a plurality of positioning columns are evenly fixedly connected to the side of the wear-resistant pad close to the outer wall, and the plurality of positioning columns are respectively inserted into a plurality of positioning holes opened at the corresponding side positions of the valve disc; a plurality of annular energy absorption grooves are evenly opened inside the wear-resistant pad.

[0017] Through the above technical scheme, when the valve disc hits the channel opening inside the valve body, it can be protected by the wear-resistant pad, and the wear-resistant pad can be quickly installed on the side of the valve disc through the positioning column, so as to facilitate rapid replacement after long-term wear. At the same time, the multiple annular energy-absorbing grooves arranged inside the wear-resistant pad can weaken the reaction force generated during the impact, thereby reducing the wear on the wear-resistant pad.

[0018] The present invention is further configured as follows: the locking assembly includes a limit block and an extension portion, the limit block and the extension portion are respectively arranged on the inner wall and the outer wall of the valve body, and are an integral hollow configuration, the interior of the extension portion is threadedly connected with a sealing sleeve near the end face position, the inner wall of the sealing sleeve is slidably connected with an adjusting rod, the outer wall of the adjusting rod is provided with a sealing bulge near the end face position, the top of the sealing bulge is provided with a sealing sheet, the outer wall of the adjusting rod is wrapped with a spring, and the two end faces are respectively pressed against the opposite faces of the sealing bulge and the sealing sleeve.

[0019] Through the above technical solution, when the adjusting rod rotates 180 degrees inside the limit block, it can make the relatively arranged groove or sealing sheet of the sealing protrusion correspond to the through groove, and under the action of the restoring elasticity of the internal spring, the adjusted adjusting rod can be stabilized, and the sealing sleeve arranged inside can limit and fix the adjusted adjusting rod.

[0020] The present invention is further configured as follows: a through groove is provided at the bottom of the limit block, and the clamping block is clamped and connected with the clamping groove provided at the bottom of the sealing protrusion through the through groove; a sealing plate is fixedly connected to the end face of the adjusting rod, and a plurality of positioning blocks and a plurality of positioning grooves are respectively provided on the opposite surfaces of the sealing plate and the sealing sleeve, and the plurality of positioning blocks are respectively clamped and connected with the plurality of positioning grooves; a pull ring is fixedly connected at the center of the end face of the sealing plate, and the sealing sheet is arranged in an arc shape, and is embedded in the mounting hole provided at the top of the sealing protrusion through the mounting block arranged at the center of the bottom.

[0021] Through the above technical solution, the pull ring is used to drive the adjusting rod on the sealing plate to move, so that the positioning block on the sealing plate is moved away from the positioning groove set on the sealing sleeve, and at the same time drives the sealing protrusion to squeeze the spring, and then the pull ring is rotated 180 degrees, and the pull ring is released, so that the rotated positioning block uses the restoring elasticity of the spring to engage with the inside of the corresponding positioning groove, thereby fixing the rotated adjusting rod. At this time, the sealing sheet or the card groove set relatively to the sealing protrusion can be placed at the through groove opened at the bottom of the limit block.

[0022] On the other hand, a method for using a cast steel swing check valve is provided, comprising the following steps: S1. First, the entire valve body is bolted to the pipes on both sides of the outside through the flanges A provided at both ends; S2. Then, the clamping assembly is adjusted according to the needs of the on-site work, and the adjusting rod on the sealing plate is moved by the pull ring, so that the positioning block on the sealing plate is away from the positioning groove set on the sealing sleeve, and at the same time, the sealing convex part is driven to squeeze the spring, and then the pull ring is rotated 180 degrees, and the pull ring is released, so that the rotated positioning block is engaged with the inside of the corresponding positioning groove by the return elasticity of the spring, so as to fix the rotated adjusting rod, and at this time, the sealing sheet or the clamping groove set relatively to the sealing convex part can be matched with the through groove opened at the bottom of the limit block; S3. Then, flow medium is introduced into the pipeline. Under the action of the flow medium, the valve disc is lifted up, so that it rotates and opens on the mounting frame through the connected swing piece, so that the counterweight block drives the clamping block to contact the bottom of the limit block. At this time, there are two situations: 1): If the card slot corresponds to the through slot, when the swing member rotates, the counterweight block at the bottom drives the card block to pass through the through slot and squeeze on the inclined surface of the card slot, and under the strong pressure, the adjusting rod slides inside the limit block and squeezes the spring. At the same time, the positioning block will not be separated from the positioning slot. After the card block enters the inside of the card slot, the resetting elasticity of the spring is used to make the adjusting rod drive the card slot to clamp and fix the card block, so that the valve disc can be limited and fixed, making the valve body a straight-through valve, reducing the pressure of the medium flowing here, and allowing the medium to flow smoothly. In the later stage, the card slot can be separated from the card block by pulling the adjusting rod through the pull ring, and the valve disc can be reset at this time; 2): If the sealing plate corresponds to the through groove, the sealing plate can seal the through groove to prevent leakage of the medium. At the same time, the counterweight block at the bottom of the swing member will drive the block to only hit the sealing plate, and during the operation of closing the valve, the valve disc can be reset under the action of the counterweight block and the reverse flow of the medium, so that the valve disc is sealed to the internal channel of the valve body through the wear-resistant pad on the end face, thereby realizing the check effect of the medium. In addition, the multiple annular energy absorption grooves opened inside the wear-resistant pad can absorb and weaken the reaction force that frequently hits the internal channel of the valve body, thereby avoiding long-term frequent impacts that cause damage to the valve disc and wear of the swing member connection, thereby increasing the service life of the entire valve body.

[0023] The beneficial effects of the present invention are as follows: 1. A cast steel swing check valve and a method for using the same proposed by the present invention is provided with a replaceable wear-resistant pad on the contact surface between the valve disc and the internal passage opening of the valve body, so that when the valve disc is frequently reset for a long time, it can avoid impact damage to the contact surface of the valve disc through the wear-resistant pad, thereby avoiding the need to replace the internal valve disc, and only the wear-resistant pad needs to be replaced, thereby reducing the subsequent maintenance cost; 2. The cast steel swing check valve and its use method proposed in the present invention provide a locking assembly inside the valve body, which facilitates the check valve to select whether to lock and fix the valve disc in different working environment requirements, thereby improving the convenience and reliability of the check valve in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of the present invention; Figure 2 It is a cross-sectional structural diagram of the present invention; Figure 3 An exploded view of the present invention; Figure 4 It is a first exploded view of the swing assembly in the present invention; Figure 5 is a second exploded view of the swing assembly of the present invention; Figure 6 for Figure 2 The enlarged view of point A in the middle; Figure 7 is a first exploded view of the engaging assembly in the present invention; Figure 8 is a second exploded view of the engaging assembly in the present invention; Fig. 9 for Figure 2 Enlarged view of point B in the middle.

[0025] In the figure: 1, valve body; 11, flange A; 12, flange B; 121, sealing groove; 122, sealing gasket; 13, fixing block; 2. Valve cover; 21. Connecting bolts; 22. Lifting ring; 3. Swing assembly; 31. Mounting frame; 32. Mounting bolt; 33. Swing piece; 331. Pin; 332. Mounting collar; 333. Counterweight; 334. Block; 34. Valve disc; 341. Mounting shaft; 342. Settling groove; 343. Positioning hole; 35. Wear pad; 351. Settling ring; 352. Positioning column; 353. Energy absorption groove; 36. Gasket; 37. Lock nut; 4. Clamping assembly; 41. Limiting block; 411. Through slot; 42. Extension portion; 43. sealing sleeve; 431. positioning groove; 44. Adjusting rod; 441. Sealing plate; 442. Positioning block; 443. Pull ring; 45. Sealing protrusion; 451. Card slot; 452. Mounting hole; 46. Sealing sheet; 461. Mounting block; 47. Spring. DETAILED DESCRIPTION

[0026] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0027] like Figure 1-Figure 3 As shown, a cast steel swing check valve and a method of using the same include a valve body 1, wherein the valve body 1 is bolted to an external pipe through flanges A11 fixedly arranged at both ends thereof, a flange B12 is fixedly connected to the top of the valve body 1, a sealing groove 121 is provided on the inner wall of the flange B12 at the top position, and a sealing gasket 122 is arranged inside the sealing groove 121, and at the same time, the bottom of the valve cover 2 is pressed against the top of the sealing gasket 122, so that when the valve cover 2 is installed, it can be sealed and connected to the top of the flange B12 through the sealing gasket 122, thereby sealing the connection, the valve cover 2 is bolted to the top of the valve body 1 for sealing the top of the valve body 1, the valve cover 2 is installed on the top of the flange B12 through a plurality of connecting bolts 21 installed in a circumferential direction near the outer wall, and a lifting ring 22 is threadedly connected to the top of the valve cover 2, so that the valve cover 2 can be installed on the top of the valve body 1 through the plurality of connecting bolts 21, and the lifting ring 22 is used to facilitate the lifting and moving installation of the entire valve body 1.

[0028] like Figure 4-Figure 6As shown, the swing assembly 3 is detachably mounted on the inner wall of the valve body 1 near the top position, and is used for swing-sealing the internal channel of the valve body 1. The swing assembly 3 includes a mounting frame 31, and the mounting frame 31 is set in an inverted U shape, and the top is set on the top of the fixing block 13 fixed to the inner wall of the valve body 1 through a mounting bolt 32, and the bottom of the mounting bolt 32 is rotatably connected with a swing member 33, and the top of the swing member 33 is fixedly provided with a pin shaft 331, and is rotatably connected to the bottom of the mounting frame 31 through the pin shaft 331, and the bottom of the swing member 33 is fixedly connected with a mounting collar 332, and the bottom of the mounting collar 332 is fixedly connected with a counterweight block 333, and the bottom position of the side wall of the counterweight block 333 is fixedly connected with a clamping block 334, and through the clamping block 3 The valve body 32 is provided with a cam 331 at the bottom of the valve body 33, and the cam 332 is provided with a cam 333 at the bottom of the valve body 33. The cam 333 is provided with a cam 334 at the bottom of the valve body 33, and the cam 333 is provided with a cam 334 ... The valve disc 34 is tightly attached to the mounting collar 332, so that the valve disc 34 can be easily installed inside the mounting collar 332 through the mounting shaft 341. The valve disc 34 is stably fixed on the mounting collar 332 by using the locking nut 37 and the sleeved gasket 36 to prevent it from loosening during long-term impact. A wear-resistant pad 35 is snap-fitted on one side of the valve disc 34, so that the mounting frame 31 can be fixed on the fixing block 13 using the mounting bolts 32. At the same time, the swing member 33 can drive the valve disc 34 at the bottom to rotate on the mounting frame 31, and the wear-resistant pad 35 can protect the valve disc 34 after reset. The side wall of the wear-resistant pad 35 is provided with a sinking ring 351, and is snap-fitted and connected to the sinking groove 34 opened on the side wall of the valve disc 34 through the sinking ring 351. 2, a plurality of positioning posts 352 are evenly fixedly connected to the side of the wear-resistant pad 35 near the outer wall, and the plurality of positioning posts 352 are respectively inserted into the plurality of positioning holes 343 opened at the corresponding side positions of the valve disc 34, and a plurality of annular energy-absorbing grooves 353 are evenly opened inside the wear-resistant pad 35, so that when the valve disc 34 hits the channel opening inside the valve body 1, it can be protected by the wear-resistant pad 35, and the wear-resistant pad 35 can be quickly installed on the side of the valve disc 34 through the positioning posts 352, so that it can be quickly replaced after long-term wear, and the plurality of annular energy-absorbing grooves 353 set inside the wear-resistant pad 35 can weaken the reaction force generated during the collision, thereby reducing the wear on the wear-resistant pad 35.

[0029] like Figure 7-Figure 9As shown, the clamping assembly 4 is installed on the side wall of the valve body 1 near the top position, and can be clamped and connected with the swing assembly 3. The clamping assembly 4 includes a limit block 41 and an extension portion 42. The limit block 41 and the extension portion 42 are respectively arranged on the inner wall and the outer wall of the valve body 1, and are an integral hollow arrangement. A through groove 411 is provided at the bottom of the limit block 41. The clamping block 334 is clamped and connected with the clamping groove 451 provided at the bottom of the sealing protrusion 45 through the through groove 411. A sealing sleeve 43 is threadedly connected to the inner side of the extension portion 42 near the end surface. An adjusting rod 44 is slidably connected to the inner wall of the sealing sleeve 43. The adjusting rod 44 The end surface of the sealing plate 441 is fixedly connected with a sealing plate 441, and the opposite surfaces of the sealing plate 441 and the sealing sleeve 43 are respectively provided with a plurality of positioning blocks 442 and a plurality of positioning grooves 431, and the plurality of positioning blocks 442 are respectively engaged with the plurality of positioning grooves 431, and a pull ring 443 is fixedly connected with the center of the end surface of the sealing plate 441, and the sealing sheet 46 is arranged in an arc shape, and is embedded in the mounting hole 452 opened at the top of the sealing protrusion 45 through the mounting block 461 arranged at the center of the bottom, and the adjusting rod 44 on the sealing plate 441 is driven by the pull ring 443 to move, so that the positioning on the sealing plate 441 is adjusted. The block 442 is away from the positioning groove 431 set on the sealing sleeve 43, and at the same time, the sealing protrusion 45 is driven to squeeze the spring 47, and then the pull ring 443 is rotated 180 degrees, and the pull ring 443 is loosened, so that the rotated positioning block 442 is engaged with the corresponding positioning groove 431 by the return elasticity of the spring 47, thereby fixing the rotated adjustment rod 44, and at this time, the sealing sheet 46 or the card groove 451 set relatively to the sealing protrusion 45 can be set to correspond to the through groove 411 opened at the bottom of the limit block 41, and the outer wall of the adjustment rod 44 is provided with a sealing protrusion near the end surface. 45, a sealing sheet 46 is provided on the top of the sealing protrusion 45, and a spring 47 is wrapped on the outer wall of the adjusting rod 44, and the two end surfaces are respectively pressed against the opposite surfaces of the sealing protrusion 45 and the sealing sleeve 43, so that when the adjusting rod 44 rotates 180 degrees inside the limit block 41, it can make the relatively arranged groove 451 of the sealing protrusion 45 or the sealing sheet 46 correspond to the through groove 411, and under the restoring elastic action of the internal spring 47, the adjusted adjusting rod 44 can be stabilized, and the sealing sleeve 43 arranged inside can limit and fix the adjusted adjusting rod 44.

[0030] like Figure 1-Figure 9 As shown, a method for using a cast steel swing check valve comprises the following steps: S1. First, the entire valve body 1 is bolted to the pipes on both sides of the outside through the flanges A11 provided at both ends; S2. Then, the engaging assembly 4 is adjusted according to the needs of the on-site work, and the adjusting rod 44 on the sealing plate 441 is driven to move by the pull ring 443, so that the positioning block 442 on the sealing plate 441 is away from the positioning groove 431 set on the sealing sleeve 43, and at the same time, the sealing protrusion 45 is driven to squeeze the spring 47, and then the pull ring 443 is rotated 180 degrees, and the pull ring 443 is released, so that the rotated positioning block 442 is engaged with the corresponding positioning groove 431 by the return elasticity of the spring 47, so that the rotated adjusting rod 44 is fixed, and at this time, the sealing sheet 46 or the card groove 451 set relatively to the sealing protrusion 45 can be placed at the through groove 411 opened at the bottom of the limit block 41; S3, then flow medium is introduced into the pipeline, and the valve disc 34 is lifted up under the action of the flow medium, so that it is rotated and opened on the mounting frame 31 through the connected swing member 33, so that the counterweight block 333 drives the clamping block 334 to contact the bottom of the limit block 41. At this time, there are two situations: 1): If the slot 451 corresponds to the through slot 411, when the swing member 33 rotates, the counterweight block 333 at the bottom drives the block 334 to pass through the through slot 411 and squeeze on the inclined surface of the slot 451, and under the strong pressure, the adjusting rod 44 slides inside the limit block 41 and squeezes the spring 47, and the positioning block 442 will not separate from the positioning slot 431. After the block 334 enters the slot 451, the resetting elasticity of the spring 47 is used to make the adjusting rod 44 drive the slot 451 to engage and fix the block 334, so that the valve flap 34 can be limited and fixed, so that the valve body 1 is a through valve, reducing the pressure of the medium flowing here, so that the medium can flow smoothly, and in the later stage, the slot 451 can be separated from the block 334 by pulling the adjusting rod 44 through the pull ring 443, and the valve flap 34 can be reset; 2): If the sealing sheet 46 corresponds to the through groove 411, the sealing sheet 46 can seal the through groove 411 to prevent leakage of the medium. At the same time, the counterweight block 333 at the bottom of the swing member 33 drives the block 334 to only hit the sealing sheet 46, and during the operation of closing the valve, the valve flap 34 can be reset under the action of the counterweight block 333 and the reverse flow of the medium, so that the valve flap 34 is sealed to the internal channel of the valve body 1 through the wear-resistant pad 35 on the end face, thereby realizing the function of checking the medium. In addition, the multiple annular energy absorption grooves 353 opened inside the wear-resistant pad 35 can absorb and weaken the reaction force that frequently hits the internal channel of the valve body 1, thereby avoiding long-term frequent impacts that cause damage to the valve flap 34 and wear at the connection of the swing member 33, thereby improving the service life of the entire valve body 1.

[0031] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A cast steel swing check valve, characterized in that: include A valve body (1), wherein the valve body (1) is bolted to an external pipeline via flanges A (11) fixedly provided at both ends of the valve body (1); A valve cover (2), the valve cover (2) being bolted to the top of the valve body (1) and used for sealing the top of the valve body (1); A swing assembly (3), the swing assembly (3) being detachably mounted on the inner wall of the valve body (1) near the top, and being used for swing-sealing the internal channel of the valve body (1); A snap-fit ​​assembly (4), wherein the snap-fit ​​assembly (4) is mounted on a side wall of the valve body (1) near the top and can be snap-fitted to the swing assembly (3).

2. A cast steel swing check valve according to claim 1, characterized in that: The top of the valve body (1) is fixedly connected to a flange plate B (12); the valve cover (2) is mounted on the top of the flange plate B (12) via a plurality of connecting bolts (21) installed in a circumferential direction near the outer wall; and the top of the valve cover (2) is threadedly connected to a lifting ring (22).

3. A cast steel swing check valve according to claim 2, characterized in that: The inner wall of the flange B (12) is provided with a sealing groove (121) at the top, and a sealing gasket (122) is arranged inside the sealing groove (121), and the bottom of the valve cover (2) is pressed against the top of the sealing gasket (122).

4. A cast steel swing check valve according to claim 1, characterized in that: The swing assembly (3) comprises a mounting frame (31), the mounting frame (31) is in an inverted U-shape, and the top is arranged on the top of a fixing block (13) fixed to the inner wall of the valve body (1) via a mounting bolt (32), the bottom of the mounting bolt (32) is rotatably connected to a swing member (33), a valve flap (34) is installed near the bottom of the swing member (33), and a wear-resistant pad (35) is snap-fitted to one side of the valve flap (34).

5. A cast steel swing check valve according to claim 4, characterized in that: The top of the swing member (33) is fixedly provided with a pin shaft (331) and is rotatably connected to the bottom of the mounting frame (31) via the pin shaft (331); the bottom of the swing member (33) is fixedly connected to a mounting collar (332); the bottom of the mounting collar (332) is fixedly connected to a counterweight (333); a clamping block (334) is fixedly connected to the bottom of the side wall of the counterweight (333) and is movably connected to the bottom of the locking assembly (4) via the clamping block (334).

6. A cast steel swing check valve according to claim 5, characterized in that: A mounting shaft (341) is fixedly connected to the center of a side of the valve disc (34) away from the wear-resistant pad (35); the mounting shaft (341) passes through the mounting collar (332); a gasket (36) is sleeved on the outer wall and a locking nut (37) is threadedly connected; the locking nut (37) is pressed against the gasket (36), and the gasket (36) is pressed against the mounting collar (332).

7. A cast steel swing check valve according to claim 6, characterized in that: The side wall of the wear-resistant pad (35) is provided with a settling ring (351), and is connected to the inside of a settling groove (342) opened on the side wall of the valve disc (34) through the settling ring (351). A plurality of positioning columns (352) are evenly fixedly connected to the side of the wear-resistant pad (35) near the outer wall, and the plurality of positioning columns (352) are respectively inserted into the inside of a plurality of positioning holes (343) opened at corresponding side positions of the valve disc (34). A plurality of annular energy absorption grooves (353) are evenly opened inside the wear-resistant pad (35).

8. The cast steel swing check valve according to claim 5, characterized in that: The engaging assembly (4) comprises a limit block (41) and an extension portion (42), wherein the limit block (41) and the extension portion (42) are respectively arranged on the inner wall and the outer wall of the valve body (1) and are integrally hollow. A sealing sleeve (43) is threadedly connected to the interior of the extension portion (42) near the end surface, an adjusting rod (44) is slidably connected to the inner wall of the sealing sleeve (43), a sealing protrusion (45) is arranged on the outer wall of the adjusting rod (44) near the end surface, a sealing sheet (46) is arranged on the top of the sealing protrusion (45), and a spring (47) is wrapped around the outer wall of the adjusting rod (44), and the two end surfaces are respectively pressed against the opposite surfaces of the sealing protrusion (45) and the sealing sleeve (43).

9. A cast steel swing check valve according to claim 8, characterized in that: A through groove (411) is provided at the bottom of the limit block (41), and the clamping block (334) is clamped and connected with a clamping groove (451) provided at the bottom of the sealing protrusion (45) through the through groove (411). A sealing plate (441) is fixedly connected to the end surface of the adjusting rod (44), and a plurality of positioning blocks (442) and a plurality of positioning grooves (431) are respectively provided on the opposite surfaces of the sealing plate (441) and the sealing sleeve (43), and the plurality of positioning blocks (442) are respectively clamped and connected to the plurality of positioning grooves (431). A pull ring (443) is fixedly connected at the center of the end surface of the sealing plate (441), and the sealing sheet (46) is arranged in an arc shape and is embedded in the inside of the mounting hole (452) provided at the top of the sealing protrusion (45) through a mounting block (461) provided at the center of the bottom.

10. A method for using a cast steel swing check valve according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. First, the entire valve body (1) is bolted to the external pipes on both sides through the flanges A (11) provided at both ends; S2. Then, the engaging assembly (4) is adjusted according to the needs of the on-site work, and the adjusting rod (44) on the sealing plate (441) is driven to move by the pull ring (443), so that the positioning block (442) on the sealing plate (441) is away from the positioning groove (431) provided on the sealing sleeve (43), and at the same time, the sealing protrusion (45) is driven to squeeze the spring (47). Then, the pull ring (443) is rotated 180 degrees, and the pull ring (443) is released, so that the positioning block (442) after rotation is engaged with the inside of the corresponding positioning groove (431) by the return elasticity of the spring (47), so that the adjusting rod (44) after rotation is fixed. At this time, the sealing sheet (46) or the clamping groove (451) arranged opposite to the sealing protrusion (45) can be placed corresponding to the through groove (411) provided at the bottom of the limit block (41); S3. Then, a flowing medium is introduced into the interior of the pipeline. Under the action of the flowing medium, the valve disc (34) is lifted up, so that it is rotated and opened on the mounting frame (31) through the connected swing member (33), so that the counterweight block (333) drives the clamping block (334) to contact the bottom of the limit block (41). At this time, there are two situations: 1): If the card slot (451) corresponds to the through slot (411), when the swing member (33) rotates, the counterweight block (333) at the bottom drives the card block (334) to pass through the through slot (411) and squeeze on the inclined surface of the card slot (451), and under the strong pressure, the adjustment rod (44) slides inside the limit block (41) and squeezes the spring (47), and the positioning block (442) will not be separated from the positioning slot (431), and the card block (334) enters the After the clamping groove (451) is inserted into the interior of the clamping groove (451), the resetting elasticity of the spring (47) is utilized to enable the adjusting rod (44) to drive the clamping groove (451) to engage and fix the clamping block (334), thereby limiting and fixing the valve flap (34), making the valve body (1) a straight-through valve, reducing the pressure of the medium flowing therein, and allowing the medium to flow smoothly. In the later stage, the clamping groove (451) can be separated from the clamping block (334) by simply pulling the adjusting rod (44) through the pull ring (443), and the valve flap (34) can be reset at this time; 2): If the sealing sheet (46) corresponds to the through groove (411), the sealing sheet (46) can seal the through groove (411) to prevent leakage of the medium. At the same time, the counterweight (333) at the bottom of the swing member (33) drives the clamping block (334) to only hit the sealing sheet (46). During the operation of closing the valve, the valve disc (34) can be reset under the action of the counterweight (333) and the reverse flow of the medium, so that the valve disc (34) is sealed to the internal channel of the valve body (1) through the wear-resistant pad (35) on the end face, thereby realizing the function of checking the medium. In addition, the multiple annular energy absorption grooves (353) provided inside the wear-resistant pad (35) can absorb and weaken the reaction force that frequently hits the internal channel of the valve body (1), thereby avoiding long-term frequent impacts that may damage the valve disc (34) and wear of the connection of the swing member (33), thereby improving the service life of the entire valve body (1).

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