Fire hydrant eight-shaped sealing ring assembly tool and assembly method

Abstract

This invention relates to the field of sealing ring assembly technology, and discloses an assembly fixture and method for a fire hydrant figure-eight shaped sealing ring. The fixture includes an upper disc, a lower disc, a movable ring, and multiple sets of clamping components. The lower disc has a lower annular groove and a central circular groove, and the inner wall of the lower annular groove has a connecting hole. The movable ring is slidably disposed within the cavity formed by the upper and lower annular grooves. During assembly, the valve cover is first pre-fixed to limit the sealing ring and maintain a gap. Then, pressurized gas is introduced into the lower annular groove to drive the movable ring to slide. When the movable ring slides above the connecting hole, the gas enters the fire hydrant valve body through the connecting hole, pushing the sealing ring to fit. This invention solves the problem of sealing rings easily falling off, leading to incomplete installation and leakage, ensuring sealing reliability, and improving assembly efficiency.

Description

Technical Field

[0001] This invention relates to the field of sealing ring assembly technology, and in particular to an assembly tooling and assembly method for a fire hydrant figure-eight sealing ring. Background Technology

[0002] A figure-eight shaped sealing ring is usually provided between the valve body and the valve cover of a fire hydrant. The sealing ring is installed in the L-shaped mounting step on the upper end face of the valve body, and its installation quality directly affects the sealing performance of the fire hydrant.

[0003] Currently, the installation of figure-eight shaped sealing rings is mainly done manually. Operators place the sealing ring inside the L-shaped mounting step, manually press it to make it initially fit the inner wall, then cover the valve and tighten the bolts. However, due to the narrow sealing groove space of the L-shaped mounting step, it is difficult for operators to effectively press and position the sealing ring. In addition, after the valve body surface is treated with epoxy powder coating, the inner wall surface of the mounting step is smooth and has low friction. During the assembly process, the sealing ring is easy to fall off from the mounting step and fall into the valve body cavity, resulting in a loose seal and causing water leakage during pressure testing, which affects the product qualification rate. Summary of the Invention

[0004] The present invention solves the following technical problems: the sealing ring is difficult to be effectively positioned in the installation step during the assembly process, and the sealing ring is easy to fall off the installation step before the valve cover is tightened, resulting in water leakage during pressure testing.

[0005] The technical solution of the present invention is as follows: an assembly fixture for a fire hydrant figure-eight sealing ring, comprising:

[0006] The upper disc component has an upper central hole and multiple sets of circumferentially distributed sliding holes on its top surface. The inner diameter of the upper central hole is the same as the inner diameter of the water inlet pipe. The bottom surface of the upper disc component has an upper annular groove. The upper central hole and the upper annular groove are not connected to each other. A sealing ring is provided on the top surface of the upper disc component.

[0007] The lower disc component has its top end fixedly connected to the bottom end of the upper disc component. The top surface of the lower disc component has a lower central circular groove and a lower annular groove. The lower central circular groove corresponds to the upper central hole, and the lower annular groove corresponds to the upper annular groove and has an air inlet on its bottom surface. The inner side wall of the lower annular groove has a lower connecting hole. The lower annular groove is connected to the lower central circular groove through the lower connecting hole. A second sealing ring and a third sealing ring are provided between the lower disc component and the upper disc component.

[0008] The movable ring is slidably set in the cavity formed by the upper annular groove and the lower annular groove. Multiple sets of sliding rods are fixed on the top surface of the movable ring. The sliding rods are slidably connected to the sliding holes one by one. The sliding rods pass through the sliding holes. The outer side wall and the inner side wall of the movable ring are respectively provided with an outer sealing ring and an inner sealing ring.

[0009] Multiple sets of clamping components are set one-to-one with the sliding rod, including mounting base one and mounting base two. Mounting base two is fixed to the top of the sliding rod and a sliding plate is rotatably connected to mounting base two. Mounting base one is fixed to the top surface of the upper disc and a pressure plate is rotatably connected to mounting base one. The pressure plate is slidably connected to the sliding plate.

[0010] Preferably, a manual pressure relief valve is installed on the bottom surface of the lower disc component, and the manual pressure relief valve is connected to the lower annular groove.

[0011] Preferably, a return spring is sleeved on the sliding rod, and the two ends of the return spring are respectively connected to the top surface of the annular groove and the top surface of the movable ring.

[0012] Preferably, a positioning groove is provided at the center of the top surface of the upper disc component. The diameter of the positioning groove matches the outer diameter of the connecting flange. The positioning groove communicates with the upper center hole. An upper sealing groove three is provided at the bottom surface of the positioning groove, and the sealing ring one is disposed in the upper sealing groove three.

[0013] Preferably, when the movable ring slides to the bottom of the lower annular groove, the pressure plate is located outside the positioning groove.

[0014] Preferably, the bottom surface of the upper disc is provided with an upper sealing groove 2 located outside the upper annular groove, and the top surface of the lower disc is provided with a lower sealing groove 2 located outside the lower annular groove. The sealing ring 2 is disposed in the cavity formed by the upper sealing groove 2 and the lower sealing groove 2.

[0015] The bottom surface of the upper disc component has an upper sealing groove 1 between the upper central hole and the upper annular groove, and the top surface of the lower disc component has a lower sealing groove 1 between the lower central circular groove and the lower annular groove. The sealing ring 3 is disposed in the cavity formed by the cooperation of the upper sealing groove 1 and the lower sealing groove 1.

[0016] Preferably, the outer sidewall and inner sidewall of the movable ring are respectively provided with an outer sealing groove and an inner sealing groove, the outer sealing ring is disposed in the outer sealing groove, and the inner sealing ring is disposed in the inner sealing groove.

[0017] A method for assembling a fire hydrant figure-eight shaped sealing ring includes the following steps:

[0018] S1. Check the tooling to ensure that the pressure plate is in the open position. Place the fire hydrant valve body on the tooling and make the connecting flange snap into the positioning groove.

[0019] S2. Place the figure-eight sealing ring inside the L-shaped installation step, so that the figure-eight sealing ring initially fits against the inner wall of the L-shaped installation step. Then use bolts to initially fix the fire hydrant valve cover to the fire hydrant valve body. At this time, the figure-eight sealing ring is under less pressure from the fire hydrant valve cover and will not fall into the fire hydrant valve body. The figure-eight sealing ring and the fire hydrant valve cover are not completely sealed.

[0020] S3. Pressurized gas is introduced into the downward annular groove through the air inlet, pushing the movable ring to slide upward. The movable ring drives multiple sets of sliding rods to slide upward synchronously. The sliding rods drive the second mounting seat to slide upward. The second mounting seat pushes the sliding plate to move upward. The sliding plate drives the pressure plate to rotate around the first mounting seat. Multiple sets of pressure plates press downward synchronously to tighten the upper end face of the connecting flange, so that the connecting flange and the upper disc part are firmly sealed.

[0021] In steps S4 and S3, when the lower end of the movable ring slides above the lower connecting hole, the pressurized gas enters the lower central groove, the upper central hole and the fire hydrant valve body through the lower connecting hole in sequence, making the pressure inside the fire hydrant valve body greater than the external pressure, and the figure-eight sealing ring is pressed tightly against the inner wall of the L-shaped installation step.

[0022] S5. Tighten the bolts between the fire hydrant valve cover and the fire hydrant valve body to stop the flow of pressurized gas into the air inlet.

[0023] S6. Open the manual pressure relief valve. The air pressure in the cavity below the moving ring decreases. The return spring pushes the moving ring to return to its original position. The pressure plate opens. At the same time, the seal between the connecting flange and the upper disc loosens. The air pressure in the lower center groove, the upper center hole and the fire hydrant valve body decreases until it is consistent with the outside air pressure.

[0024] S7. Remove the assembled fire hydrant valve body, fire hydrant valve cover and figure-eight sealing ring from the tooling and wait for the next assembly.

[0025] Preferably, in step S4, the pressure of the pressurized gas introduced through the air inlet is 0.2MPa to 0.6MPa.

[0026] Preferably, in step S4, after the pressurized gas enters the fire hydrant valve body, the part where the figure-eight sealing ring is in contact with the inner wall of the L-shaped mounting step first forms a partial seal, while the part that is not in contact with the outside is connected. The pressurized gas gradually seeps in along the gap of the part that is not in contact with the outside and pushes the figure-eight sealing ring to gradually expand and fit until the figure-eight sealing ring is completely in contact with the inner wall of the L-shaped mounting step.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The tooling of the present invention, combined with the introduction of pressurized gas into the fire hydrant valve body, utilizes the characteristic of the gas gradually seeping into the gap between the sealing ring and the inner wall of the mounting step, to push the figure-eight sealing ring from partial contact to complete contact with the inner wall of the L-shaped mounting step, realizing the automatic positioning and contact of the sealing ring in a narrow space, solving the technical problems of difficulty in manual pressing and easy detachment of the sealing ring into the valve body cavity, avoiding incomplete installation and water leakage, and improving the product qualification rate.

[0029] 2. In this invention, by opening a lower connecting hole in the inner wall of the lower annular groove, the movable ring automatically controls the switching of the air passage during its upward sliding. When the movable ring slides above the lower connecting hole, the air passage opens, and pressurized gas automatically enters the fire hydrant valve body to press the figure-eight sealing ring. Throughout the process, the air passage switching is completed by the mechanical position change of the movable ring, and one air source simultaneously realizes the two actions of pressing the flange and pressing the figure-eight sealing ring. Attached Figure Description

[0030] Figure 1 This is a perspective view of the tooling in this invention;

[0031] Figure 2 Exploded view of the tooling after the clamping components have been removed;

[0032] Figure 3 This is a schematic diagram of the upper circular component;

[0033] Figure 4 This is a structural schematic diagram of the lower circular disc component;

[0034] Figure 5 This is a schematic diagram of the structure of the movable ring;

[0035] Figure 6 Cross-sectional view of the tooling after removing the clamping components.

[0036] Figure 7 This is a schematic diagram of the clamping assembly and sliding rod.

[0037] Figure 8 This is a cross-sectional view of the pressure plate and the sliding plate;

[0038] Figure 9 This is a partial sectional view of the tooling during clamping.

[0039] Figure 10 This is a partial sectional view of the tooling when it is loosened.

[0040] Figure 11 for Figure 9 Schematic diagram after adding a return spring;

[0041] Figure 12 Exploded view of the fire hydrant valve body, fire hydrant valve cover, and figure-eight sealing ring;

[0042] Figure 13 A 3D view of the installation of a figure-eight sealing ring for a fire hydrant using tooling.

[0043] Figure label:

[0044] 1. Upper disc component; 11. Upper center hole; 12. Upper annular groove; 13. Sliding hole; 14. Upper sealing groove one; 15. Upper sealing groove two; 16. Positioning groove; 17. Upper sealing groove three; 2. Lower disc component; 21. Lower center circular groove; 22. Lower connecting hole; 23. Lower annular groove; 24. Air inlet; 25. Lower sealing groove one; 26. Lower sealing groove two; 27. Manual pressure relief valve; 3. Movable ring; 31. Sliding rod; 32. 33. Outer sealing groove; 34. Outer sealing ring; 35. Inner sealing groove; 36. Inner sealing ring; 37. Return spring; 48. Pressing assembly; 49. Mounting seat one; 40. Pressure plate; 41. Sliding plate; 42. Mounting seat two; 5. Sealing ring one; 6. Sealing ring two; 7. Sealing ring three; 80. Fire hydrant valve body; 81. Inlet pipe; 82. Connecting flange; 83. L-shaped mounting step; 90. Fire hydrant valve cover; 91. Figure-eight sealing ring. Detailed Implementation

[0045] Example 1

[0046] Reference Figures 1-13 An assembly tooling for a fire hydrant figure-eight sealing ring includes an upper disc 1, a lower disc 2, a movable ring 3, and four sets of clamping components 4.

[0047] Reference Figure 1 and Figure 3 The upper disc component 1 has a disc-shaped structure with an upper central hole 11 at the center of its top surface. The inner diameter of the upper central hole 11 is the same as the inner diameter of the water inlet pipe 81 of the fire hydrant valve body 8. The top surface of the upper disc component 1 also has four sets of circumferentially distributed sliding holes 13, which are evenly distributed at 90° intervals along the top surface of the upper disc component 1. The bottom surface of the upper disc component 1 has an upper annular groove 12. The upper central hole 11 and the upper annular groove 12 are not connected to each other, and an annular partition wall is left between them. The center of the top surface of the upper disc component 1 has a positioning groove 16. The positioning groove 16 is a circular groove, the diameter of which matches the outer diameter of the connecting flange 82 of the fire hydrant valve body 8. The connecting flange 82 can be inserted into the positioning groove 16 to achieve radial positioning. The positioning groove 16 is connected to the upper central hole 11. The bottom surface of the positioning groove 16 is provided with an upper sealing groove 3 17, and the sealing ring 1 5 is embedded in the upper sealing groove 3 17. The bottom surface of the upper disc part 1 is also provided with an upper sealing groove 2 15 located outside the upper annular groove 12. The bottom surface of the upper disc part 1 is also provided with an upper sealing groove 14 located between the upper central hole 11 and the upper annular groove 12.

[0048] Reference Figure 1 and Figure 4The lower disc component 2 has a disc-shaped structure, and its top surface is fixedly connected to the bottom surface of the upper disc component 1 by bolts. The top surface of the lower disc component 2 has a lower central circular groove 21, which corresponds to and communicates with the upper central hole 11. The top surface of the lower disc component 2 also has a lower annular groove 23, which corresponds to the upper annular groove 12. The bottom surface of the lower annular groove 23 has an air inlet 24, which penetrates the bottom surface of the lower disc component 2 and is used to introduce pressurized gas into the cavity below the movable ring 3. The inner wall of the lower annular groove 23 has a lower connecting hole 22, which connects the lower annular groove 23 to the lower central circular groove 21.

[0049] The top surface of the lower disc 2 has a lower sealing groove 26 located outside the lower annular groove 23. A second sealing ring 6 is set in the cavity formed by the upper sealing groove 15 and the lower sealing groove 26 to seal the outer ring of the cavity below the movable ring 3. The top surface of the lower disc 2 has a lower sealing groove 25 located between the lower central circular groove 21 and the lower annular groove 23. A third sealing ring 7 is set in the cavity formed by the upper sealing groove 14 and the lower sealing groove 25 to seal the inner ring of the cavity below the movable ring 3. A manual pressure relief valve 27 is installed on the bottom surface of the lower disc 2. The manual pressure relief valve 27 is connected to the lower annular groove 23 to discharge the pressurized gas in the cavity below the movable ring 3 to the outside atmosphere.

[0050] Reference Figure 5 and Figure 11 The upper annular groove 12 and the lower annular groove 23 form a closed annular cavity after docking. The movable ring 3 is an annular component that is slidably disposed in the cavity. The thickness of the movable ring 3 is less than the height of the cavity, so that the movable ring 3 can slide up and down in the cavity. An outer sealing groove 32 is provided on the outer side wall of the movable ring 3. An outer sealing ring 33 is embedded in the outer sealing groove 32 and slides and seals with the inner wall of the lower annular groove 23. An inner sealing groove 34 is provided on the inner side wall of the movable ring 3. An inner sealing ring 35 is embedded in the inner sealing groove 34 and slides and seals with the outer wall of the upper central hole 11 and the lower central circular groove 21. Through the sliding seal of the outer sealing ring 33 and the inner sealing ring 35, the upper cavity and the lower cavity of the movable ring 3 are not connected to each other, ensuring that the driving gas will not leak from the gap between the inner and outer walls of the movable ring 3 when it pushes the movable ring 3 to move upward.

[0051] Four sets of sliding rods 31 are fixed on the top surface of the movable ring 3. The four sets of sliding rods 31 are evenly distributed at 90° intervals along the circumference of the top surface of the movable ring 3. The lower end of the sliding rod 31 is fixed to the top surface of the movable ring 3, and the upper end passes through the corresponding sliding hole 13 and extends out of the top surface of the upper disc 1. The sliding rod 31 and the sliding hole 13 are in sliding fit. The sliding hole 13 guides the sliding rod 31 to ensure that each sliding rod 31 remains parallel when moving up and down. A return spring 36 is also sleeved on the sliding rod 31. The return spring 36 is a compression spring. The upper end of the return spring 36 is connected to the top surface of the upper annular groove 12, and the lower end is connected to the top surface of the movable ring 3.

[0052] Reference Figure 2 , Figure 7 and Figure 8 Four sets of clamping components 4 are respectively set with four sets of sliding rods 31. Each set of clamping components 4 includes a first mounting seat 41, a second mounting seat 44, a sliding plate 43 and a pressure plate 42. The first mounting seat 41 is fixed to the top surface of the upper disc 1 and is located outside the positioning groove 16. The pressure plate 42 is rotatably mounted on the first mounting seat 41 and can rotate in the vertical plane. The side of the pressure plate 42 near the positioning groove 16 is used to contact and press the upper end face of the connecting flange 82. The side of the pressure plate 42 away from the positioning groove 16 is slidably connected to the sliding plate 43. The second mounting seat 44 is fixed to the top of the sliding rod 31 and moves up and down with the sliding rod 31. The sliding plate 43 is rotatably connected to the second mounting seat 44. When the sliding rod 31 moves up and down, the sliding plate 43 slides relative to the pressure plate 42, thereby pushing the pressure plate 42 to rotate around its connection point with the first mounting seat 41.

[0053] Reference Figure 9 and Figure 10The working principle of the clamping assembly 4 is as follows: When the movable ring 3 is at the bottom of the lower annular groove 23, the sliding rod 31 is at its lowest position. At this time, the movable ring 3 is below the lower connecting hole 22. When pressurized gas is introduced into the cavity below the movable ring 3, the pressurized gas will not enter the lower connecting hole 22, and the side of the pressure plate 42 near the positioning groove 16 is located outside the positioning groove 16, without obstructing the upper and lower channels of the positioning groove 16. The connecting flange 82 can be freely inserted into or removed from the positioning groove 16 without interfering with the pressure plate 42. When pressurized gas is introduced into the cavity below the movable ring 3 through the air inlet 24, the air pressure pushes... The movable ring 3 slides upward, driving the four sets of sliding rods 31 to move upward synchronously. The sliding rods 31 drive the mounting base 44 and the sliding plate 43 to move upward synchronously. The sliding plate 43 slides relative to the pressure plate 42, thereby pushing the pressure plate 42 to rotate. The side of the pressure plate 42 near the positioning groove 16 swings downward with the rotation, pressing the upper end face of the connecting flange 82. The four sets of pressure plates 42 swing downward synchronously, pressing the connecting flange 82 evenly into the positioning groove 16. The sealing ring 5 is compressed between the end face of the connecting flange 82 and the bottom surface of the positioning groove 16, achieving a stable seal between the connecting flange 82 and the upper disc part 1.

[0054] As the pressure plate is about to press the connecting flange 82, the movable ring 3 slides above the lower connecting hole 22, allowing the pressurized gas to enter the lower central groove 21 and the upper central hole 11 through the lower connecting hole 22, and then enter the fire hydrant valve body 8, pressing the figure-eight sealing ring 91 onto the L-shaped mounting step of the fire hydrant valve body 8.

[0055] In this embodiment, pressurized gas is introduced into the air inlet 24 through an air pump and an air pipe. The air pump is a constant pressure air pump, which can automatically maintain a constant output air pressure and ensure stable air pressure during the operation of the tooling.

[0056] When it is necessary to loosen the fixture, open the manual pressure relief valve 27. The pressurized gas in the cavity below the movable ring 3 is discharged, the air pressure decreases, the return spring 36 releases its elastic potential energy to push the movable ring 3 to return downward. The movable ring 3 drives the sliding rod 31 to move downward. The sliding rod 31 drives the mounting base 44 and the sliding plate 43 to move downward. The sliding plate 43 slides in the opposite direction relative to the pressure plate 42, pushing the pressure plate 42 to rotate in the opposite direction. The side of the pressure plate 42 near the positioning groove 16 swings upward and opens, releasing the pressure on the upper end face of the connecting flange 82. At this time, the seal between the bottom surface of the connecting flange 82 and the bottom surface of the positioning groove 16 is loosened, and the fixture can be removed manually.

[0057] With the above structure, when pressurized gas enters the cavity below the movable ring 3 from the air inlet 24, the four sets of clamping components 4 act synchronously, and the four sets of pressure plates 42 simultaneously apply downward clamping force to the connecting flange 82, so that the connecting flange 82 is subjected to balanced force, avoiding leakage caused by uneven pressure on the sealing ring 5 due to unilateral clamping; after the pressure is released by the manual pressure relief valve 27, the pressure plate 42 opens automatically, and the workpiece can be smoothly removed. The entire clamping and loosening process is driven by air pressure, and the operator does not need to manually operate the pressure plate; when using the fixture, the operator only needs to place the fire hydrant valve body 8 on the fixture, so that the connecting flange 82 is inserted into the positioning groove 16, and then pressurized gas is introduced through the air inlet 24 to complete the clamping and sealing of the fixture and the assembly of the figure-eight sealing ring 91. After the assembly is completed, the manual pressure relief valve 27 is opened, and the valve body can be manually removed as a whole. The operation is simple and the assembly efficiency is high.

[0058] In this embodiment, the movable ring 3, the lower connecting hole 22, and the introduction of pressurized gas all work together. The movable ring 3 not only uses pressurized gas to drive the clamping assembly 4, but also extends and opens the pressurized gas into the fire hydrant valve body 8. The lower connecting hole 22 not only introduces pressurized gas into the fire hydrant valve body 8, but also reduces the risk of damage caused by a sudden increase in pressure in the movable cavity of the movable ring 3.

[0059] Example 2

[0060] A method for assembling a fire hydrant figure-eight sealing ring, based on the assembly fixture in Embodiment 1, includes the following steps:

[0061] Step 1: Confirm that the pressure plate 42 is in the open state. The open state means that the movable ring 3 is located at the bottom of the lower annular groove 23, the free end of the pressure plate 42 is located outside the positioning groove 16, and the connecting flange 82 can be freely inserted into the positioning groove 16 without interfering with the pressure plate 42. Place the fire hydrant valve body 8 horizontally, so that the connecting flange 82 of the water inlet pipe 81 faces downward. Place the tool below the connecting flange 82 so that the connecting flange 82 is inserted into the positioning groove 16. At this time, the sealing ring 5 is attached to the lower end face of the connecting flange 82, and the tool supports the fire hydrant valve body 8 from below.

[0062] Step 2: Place the figure-eight sealing ring 91 inside the L-shaped mounting step 83 on the upper end face of the fire hydrant valve body 8. Manually press it so that the figure-eight sealing ring 91 initially fits against the inner wall of the L-shaped mounting step 83. Place the fire hydrant valve cover 9 on the upper end of the fire hydrant valve body 8, so that the lower end face of the fire hydrant valve cover 9 contacts the upper surface of the figure-eight sealing ring 91. Insert the bolt and pre-tighten it to initially fix the fire hydrant valve cover 9 on the fire hydrant valve body 8. At this time, the fire hydrant valve cover 9 only serves to limit the figure-eight sealing ring 91 in the vertical direction, that is, to prevent the sealing ring from falling out of the L-shaped mounting step 83 and into the fire hydrant valve body 8 under the action of gravity. Since the bolt pre-tightening force is very small, there are still gaps between the figure-eight sealing ring 91 and the fire hydrant valve cover 9, and between the sealing ring and the inner wall of the L-shaped mounting step 83, which allow gas to pass through. It is not completely sealed. At this point, although the figure-eight sealing ring 91 is initially attached to the inner wall of the L-shaped mounting step 83, it is not yet fully attached. If the bolt is tightened directly, the figure-eight sealing ring 91 may slip into the fire hydrant valve body 8 due to compression.

[0063] Step 3: Pressurized gas is introduced into the annular groove 23 through the air inlet 24. The pressure is 0.2MPa to 0.6MPa. In this embodiment, 0.4MPa is used. The gas enters the cavity below the movable ring 3, pushing the movable ring 3 to move upward. The movable ring 3 drives the four sets of sliding rods 31 to slide upward synchronously. The sliding rods 31 drive the mounting base 44 and the sliding plate 43 to move upward. The sliding plate 43 slides relative to the pressure plate 42, driving the pressure plate 42 to rotate around its connection point with the mounting base 41. The four sets of pressure plates 42 swing downward synchronously, and their free ends press against the upper end face of the connecting flange 82, pressing the connecting flange 82 into the positioning groove 16. The sealing ring 5 is compressed and achieves a seal between the connecting flange 82 and the upper disc part 1. The four sets of pressure plates 42 press synchronously, so that the connecting flange 82 is subjected to uniform force and the seal is reliable.

[0064] In steps four and three, when the pressure plate is about to press the connecting flange 82, the movable ring 3 slides above the lower connecting hole 22, allowing the pressurized gas to enter the lower central groove 21 and the upper central hole 11 through the lower connecting hole 22, and then enter the fire hydrant valve body 8. Since the sealing ring is not completely sealed in step two, the pressurized gas in the valve body gradually seeps in along the gap between the sealing ring and the inner wall of the L-shaped mounting step 83 and the valve cover. The gas first penetrates into the tiny gaps around the contact area between the sealing ring and the inner wall of the mounting step. After forming a local seal in these areas, the unsealed areas are still connected to the outside, and the gas continues to... The gas continues to flow into the gaps where the seal is not yet in place, further pushing the remaining part of the seal ring to adhere tightly to the inner wall of the L-shaped mounting step 83. As the gas continues to infiltrate, the seal ring is gradually pushed and expanded by the air pressure until the entire seal ring is adhered to the inner wall of the L-shaped mounting step 83. In this process, the pressurized gas plays the role of automatically finding gaps and pushing the seal ring to adhere, eliminating the need for manual pressing within the narrow mounting step. This overcomes the technical problem that the seal ring is difficult to effectively position by manual pressing and is prone to falling off because the inner wall of the mounting step is smooth and has low frictional resistance after epoxy spraying.

[0065] In this step, due to the presence of the lower connecting hole 22, when the movable ring 3 slides above the lower connecting hole 22, some of the pressurized gas is diverted into the fire hydrant valve body 8 through the lower connecting hole 22, and the pressure in the lower annular groove 23 will decrease until the pressurized gas fills the fire hydrant valve body 8. Some of the pressurized gas will flow out from the gap between the connecting flange 82 and the bottom surface of the positioning groove 16. However, the overall air pressure inside the fire hydrant valve body 8 is always greater than the external air pressure. Therefore, the gap between the connecting flange 82 and the bottom surface of the positioning groove 16 will not affect the tightening and assembly of the figure-eight sealing ring 91.

[0066] Step 5: Keep pressurized gas flowing into the air inlet 24. Use a wrench to tighten the bolts between the fire hydrant valve cover 9 and the fire hydrant valve body 8. During the tightening process, the figure-eight sealing ring 91 is in a state of air pressure fit and will not be displaced or curled due to the rotation or pressure of the valve cover. After the bolts are tightened, stop the flow of pressurized gas into the air inlet 24.

[0067] Step 6: Open the manual pressure relief valve 27. The pressurized gas in the cavity below the movable ring 3 is discharged through the manual pressure relief valve 27, reducing the air pressure in the cavity. The return spring 36 pushes the movable ring 3 to return downward. The movable ring 3 drives the sliding rod 31 to move downward. The sliding rod 31 drives the mounting base 44 and the sliding plate 43 to move downward. The sliding plate 43 slides in the opposite direction relative to the pressure plate 42, driving the pressure plate 42 to rotate in the opposite direction around its connection point with the mounting base 41. The side of the pressure plate 42 near the positioning groove 16 swings upward and opens, releasing the pressure on the upper end face of the connecting flange 82. At this time, the seal between the bottom surface of the connecting flange 82 and the bottom surface of the positioning groove 16 loosens, and the gas inside the fire hydrant valve body 8 is discharged through the gap between the bottom surface of the connecting flange 82 and the bottom surface of the positioning groove 16. The air pressure inside the valve body gradually decreases until it is consistent with the outside air pressure.

[0068] Step 7: Remove the assembled fire hydrant valve body 8, fire hydrant valve cover 9, and figure-eight sealing ring 91 vertically upward from the top of the tooling, so that the connecting flange 82 is disengaged from the positioning groove 16, completing one assembly and waiting for the next assembly.

Claims

1. An assembly fixture for a fire hydrant figure-eight shaped sealing ring, characterized in that, include: The upper disc component (1) has an upper central hole (11) and multiple sets of sliding holes (13) evenly distributed around its top surface. The inner diameter of the upper central hole (11) is the same as the inner diameter of the water inlet pipe (81). The bottom surface of the upper disc component (1) has an upper annular groove (12). The upper central hole (11) and the upper annular groove (12) are not connected to each other. A sealing ring (5) is provided on the top surface of the upper disc component (1). The lower disc component (2) is fixedly connected to the bottom end of the upper disc component (1) at its top end. The lower disc component (2) has a lower central circular groove (21) and a lower annular groove (23) on its top surface. The lower central circular groove (21) corresponds to the upper central hole (11), and the lower annular groove (23) corresponds to the upper annular groove (12) and has an air inlet (24) on its bottom surface. The lower annular groove (23) has a lower connecting hole (22) on its inner side wall. The lower annular groove (23) is connected to the lower central circular groove (21) through the lower connecting hole (22). A sealing ring 2 (6) and a sealing ring 3 (7) are provided between the lower disc component (2) and the upper disc component (1). The movable ring (3) is slidably disposed in the cavity formed by the upper annular groove (12) and the lower annular groove (23). Multiple sets of sliding rods (31) are fixed on the top surface of the movable ring (3). The sliding rods (31) are correspondingly disposed with the sliding holes (13) and slidably connected. The sliding rods (31) pass through the sliding holes (13). The outer side wall and the inner side wall of the movable ring (3) are respectively provided with an outer sealing ring (33) and an inner sealing ring (35). Multiple sets of clamping components (4) are set one-to-one with the sliding rod (31), including mounting seat one (41) and mounting seat two (44). Mounting seat two (44) is fixed to the top of the sliding rod (31). A sliding plate (43) is rotatably connected to mounting seat two (44). Mounting seat one (41) is fixed to the top surface of the upper disc (1). A pressure plate (42) is rotatably connected to mounting seat one (41). The pressure plate (42) is slidably connected to the sliding plate (43).

2. The assembly fixture for a fire hydrant figure-eight sealing ring according to claim 1, characterized in that, The bottom surface of the lower disc component (2) is equipped with a manual pressure relief valve (27), which is connected to the lower annular groove (23).

3. The assembly fixture for a fire hydrant figure-eight sealing ring according to claim 1, characterized in that, A return spring (36) is sleeved on the sliding rod (31), and the two ends of the return spring (36) are respectively connected to the top surface of the annular groove (12) and the top surface of the movable ring (3).

4. The assembly fixture for a fire hydrant figure-eight sealing ring according to claim 1, characterized in that, The upper disc component (1) has a positioning groove (16) at the center of its top surface. The diameter of the positioning groove (16) matches the outer diameter of the connecting flange (82). The positioning groove (16) is connected to the upper center hole (11). The bottom surface of the positioning groove (16) has an upper sealing groove three (17). The sealing ring one (5) is set in the upper sealing groove three (17).

5. The assembly fixture for a fire hydrant figure-eight sealing ring according to claim 4, characterized in that, When the movable ring (3) slides to the bottom of the lower annular groove (23), the pressure plate (42) is located outside the positioning groove (16).

6. The assembly fixture for a fire hydrant figure-eight sealing ring according to claim 1, characterized in that, The upper disc component (1) has an upper sealing groove 2 (15) on its bottom surface located outside the upper annular groove (12), and the lower disc component (2) has a lower sealing groove 2 (26) on its top surface located outside the lower annular groove (23). The sealing ring 2 (6) is disposed in the cavity formed by the upper sealing groove 2 (15) and the lower sealing groove 2 (26). The bottom surface of the upper disc (1) is provided with an upper sealing groove (14) between the upper central hole (11) and the upper annular groove (12). The top surface of the lower disc (2) is provided with a lower sealing groove (25) between the lower central circular groove (21) and the lower annular groove (23). The sealing ring (7) is provided in the cavity formed by the upper sealing groove (14) and the lower sealing groove (25).

7. The assembly fixture for a fire hydrant figure-eight sealing ring according to any one of claims 1 to 6, characterized in that, The outer and inner walls of the movable ring (3) are respectively provided with an outer sealing groove (32) and an inner sealing groove (34). The outer sealing ring (33) is located in the outer sealing groove (32), and the inner sealing ring (35) is located in the inner sealing groove (34).

8. A method for assembling a figure-eight shaped sealing ring for a fire hydrant, characterized in that, The assembly fixture based on the fire hydrant figure-eight sealing ring according to claims 1-7 includes the following steps: S1. Check the tooling to ensure that the pressure plate (42) is open. Place the fire hydrant valve body (8) on the tooling and make the connecting flange (82) snap into the positioning groove (16). S2. Place the figure-eight sealing ring (91) inside the L-shaped installation step (83) so that the figure-eight sealing ring (91) initially fits the inner wall of the L-shaped installation step (83). Then use bolts to initially fix the fire hydrant valve cover (9) on the fire hydrant valve body (8). At this time, the figure-eight sealing ring (91) is under less pressure from the fire hydrant valve cover (9) and will not fall into the fire hydrant valve body (8). The figure-eight sealing ring (91) and the fire hydrant valve cover (9) are not completely sealed. S3. Pressurized gas is introduced into the downward annular groove (23) through the air inlet (24), pushing the movable ring (3) to slide upward. The movable ring (3) drives multiple sets of sliding rods (31) to slide upward synchronously. The sliding rods (31) drive the second mounting seat (44) to slide upward. The second mounting seat (44) pushes the sliding plate (43) to move upward. The sliding plate (43) drives the pressure plate (42) to rotate around the first mounting seat (41). Multiple sets of pressure plates (42) press down synchronously to tighten the upper end face of the connecting flange (82), so that the connecting flange (82) and the upper disc part (1) are firmly sealed. In steps S4 and S3, when the lower end of the movable ring (3) slides above the lower connecting hole (22), the pressurized gas enters the lower central groove (21), the upper central hole (11) and the fire hydrant valve body (8) in sequence through the lower connecting hole (22), making the pressure inside the fire hydrant valve body (8) greater than the external pressure, and the figure-eight sealing ring (91) is pressed tightly against the inner wall of the L-shaped mounting step (83); S5. Tighten the bolts between the fire hydrant valve cover (9) and the fire hydrant valve body (8) to stop the flow of pressurized gas into the air inlet (24); S6. Open the manual pressure relief valve (27). The air pressure in the cavity below the movable ring (3) decreases. The reset spring (36) pushes the movable ring (3) to reset downwards. The pressure plate (42) opens. At the same time, the seal between the connecting flange (82) and the upper disc (1) loosens. The air pressure in the lower central groove (21), the upper central hole (11) and the fire hydrant valve body (8) decreases until it is consistent with the outside. S7. Remove the assembled fire hydrant valve body (8), fire hydrant valve cover (9) and figure-eight sealing ring (91) from the tooling and wait for the next assembly.

9. The assembly method of a fire hydrant figure-eight sealing ring according to claim 8, characterized in that, In step S4, the pressure of the pressurized gas introduced through the air inlet (24) is 0.2MPa to 0.6MPa.

10. The assembly method of a fire hydrant figure-eight sealing ring according to claim 8, characterized in that, In step S4, after the pressurized gas enters the fire hydrant valve body (8), the part where the figure-eight sealing ring (91) is in contact with the inner wall of the L-shaped mounting step (83) first forms a partial seal, while the part that is not in contact with the outside is connected to the outside. The pressurized gas gradually seeps in along the gap of the part that is not in contact with the outside and pushes the figure-eight sealing ring (91) to gradually expand and fit until the figure-eight sealing ring (91) is completely in contact with the inner wall of the L-shaped mounting step (83).

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