Fire hydrant

Abstract

The invention relates to the technical field of fluid control, in particular to a fire hydrant which comprises a spring cavity, a valve body extension seat and a valve body which are sequentially connected from top to bottom, an adjusting assembly is arranged in the spring cavity and comprises a spring and a spring pressing plate, and the spring provides tension for the spring pressing plate; a cavity, a piston and a valve rod are arranged in the valve body extension seat, the piston is fixed on the valve rod, one end of the valve rod is fixedly connected with the adjusting assembly, and the other end extends into the valve body; a pressure guide flow channel is arranged in the valve rod, the pressure guide flow channel is communicated with the valve body and the cavity and used for guiding water to enter the cavity and then extrude the piston, a water inlet cavity, a water inlet and a water outlet are formed in the valve body, the valve seat is arranged at the joint of the water inlet cavity and the water inlet, the valve seat is used for controlling water to flow in and out, and the valve seat is fixedly connected with the extending part of the valve rod. The system has the effect that no matter how the pressure of the pipe network fluctuates, firemen can obtain a safe, stable and controllable water source.

Description

Technical Field

[0001] This application relates to the field of fluid control technology, and in particular to a fire hydrant. Background Technology

[0002] Fire hydrants, as key water intake devices in urban fire protection pipe networks, play a vital role in firefighting operations. While complex urban fire protection pipe networks provide strong protection for urban fire safety, they also bring numerous challenges. Factors such as undulating urban terrain, varying distances between fire pipelines, and dynamic fluctuations in water consumption all contribute to significant differences in the inlet pressure of fire hydrants at different locations within the network. This pressure instability adversely affects the smooth operation of firefighting efforts. Ensuring that fire hydrants operate stably and reliably under various conditions has become a crucial issue that urgently needs to be addressed in the fire protection field.

[0003] To address the problem of excessively high inlet pressure in fire hydrants, several common pressure-reducing methods exist, with the fixed throttling type being a typical example. This method uses a fixed throttling device inside the fire hydrant to reduce water pressure based on the throttling principle. When water flows through the throttling device, the flow velocity increases due to the reduced channel area, thus lowering the pressure. However, the pressure-reducing effect of this method depends on the inlet pressure and the fixed parameters of the throttling device. Additionally, some fire hydrants employ simple mechanical adjustment devices, controlling water pressure by manually adjusting the valve opening. However, this method requires manual intervention, is inconvenient to operate, and is difficult to respond quickly in emergencies.

[0004] While traditional pressure-reducing fire hydrants can lower outlet pressure to some extent, they suffer from a significant drawback: unstable pressure reduction. The outlet pressure of fixed throttling pressure-reducing fire hydrants fluctuates with changes in inlet pressure; when the inlet pressure increases, the outlet pressure also increases accordingly, making it impossible to maintain stability. This instability makes it difficult for firefighters to accurately predict and control water pressure at the fire scene, requiring constant adjustments to operational strategies and causing considerable inconvenience to firefighting operations. This is especially true under complex conditions of dynamically changing inlet pressure, where traditional pressure-reducing methods often fail to meet practical needs. Summary of the Invention

[0005] To ensure firefighters have access to a safe, stable, and controllable water source regardless of fluctuations in pipeline pressure, the purpose of this application is to provide a fire hydrant. The technical solution adopted is as follows: It includes a spring cavity, a valve body extension seat, and a valve body, which are connected sequentially from top to bottom; The spring cavity is provided with an adjustment component, which includes a spring and a spring pressure plate. The spring is used to provide tension to the spring pressure plate. The valve body extension seat is provided with a cavity, a piston and a valve stem. The piston is fixed on the valve stem. One end of the valve stem is fixedly connected to the adjusting assembly, and the other end extends through the valve body extension seat into the valve body. The valve stem is provided with a pressure-guiding channel, which connects the valve body and the cavity and is used to guide water into the cavity to squeeze the piston. The valve body is provided with an inlet chamber, an inlet, an outlet, and a valve seat. The valve seat is located at the connection between the inlet chamber and the inlet. The valve seat is used to control the inlet and outlet of water. The valve seat is fixedly connected to the extension of the valve stem.

[0006] By adopting the above technical solution, when water flows into the cavity from the pressure channel, it compresses the piston and, in conjunction with the tension of the adjusting component spring, automatically slides up and down according to changes in water pressure. This achieves a dynamic balance between the cavity pressure and the spring tension, allowing for adaptive adjustment without manual intervention. This maintains stable valve control, preventing equipment damage caused by excessively high or low inlet pressure, or significant inconvenience to firefighting operations due to unstable outlet pressure. It ensures that firefighters have a safe, stable, and controllable water source regardless of fluctuations in the pipeline pressure.

[0007] Optionally, the adjusting assembly further includes a spring guide rod, with the spring sleeved on the spring guide rod. The two ends of the spring are respectively fixedly connected to the bottom of the inner cavity of the spring cavity and the spring pressure plate. The spring pressure plate is fixedly connected to the spring guide rod, and the spring guide rod passes through the bottom of the spring cavity and is fixedly connected to the valve stem.

[0008] By adopting the above technical solution, the spring guide rod guides the spring to compress and release in a straight line, preventing the spring from deflecting or jamming and ensuring uniform tension application; the spring pressure plate is fixedly connected to the spring guide rod, making the spring preload adjustable, thereby optimizing the response sensitivity of the adjustment component, improving the stability and control accuracy of the fire hydrant under water pressure changes, while reducing component wear and extending spring life.

[0009] Optionally, the pressure channel includes a main channel and a branch channel, the main channel being located on the central axis of the valve stem, and the branch channel connecting the main channel and the cavity.

[0010] By adopting the above technical solution, the main channel guides the water pressure, and the branch channel disperses the water pressure to multiple points in the cavity, so that the water flow acts on the piston more evenly and avoids piston wear or unstable movement caused by local pressure concentration. This design improves the efficiency of the pressure-gathering system, ensures that the valve stem responds quickly and consistently, and enhances the reliability and sealing of the fire hydrant in high-pressure environments.

[0011] Optionally, the diversion channels are provided in multiple ways and are evenly distributed along the circumference of the valve stem.

[0012] By adopting the above technical solution, the water pressure is symmetrically transmitted to all parts of the cavity through the uniform arrangement of multiple flow channels, so that the piston is subjected to balanced force, reducing the lateral stress or vibration of the valve stem, thereby preventing component fatigue damage. This design further optimizes the water flow distribution and improves the operational stability and durability of the fire hydrant, especially under frequent start-stop conditions.

[0013] Optionally, the inlet is located at the bottom of the valve body, and the outlet is located on the side wall of the valve body, with the inlet, inlet chamber and outlet forming a connected water flow channel.

[0014] By adopting the above technical solution, the water inlet is set at the bottom of the valve body, which facilitates direct water intake from the water source and reduces water flow resistance; the water outlet is set on the side wall of the valve body, which facilitates connection to fire water pipes or hoses, meets actual installation requirements, optimizes the water flow path, reduces pressure loss, and makes the fire hydrant structure compact, making it easy to deploy and maintain in various scenarios.

[0015] Optionally, the water outlet is provided with a cap and a water pipe connector, the water pipe connector is connected to the water outlet, and the cap and the water pipe connector are detachably connected by a locking mechanism.

[0016] By adopting the above technical solutions, the cap can effectively prevent dust, foreign objects or moisture from entering the water outlet, avoiding blockage or corrosion; the locking connection method allows the cap and water pipe joint to be quickly disassembled and installed, simplifying the maintenance and emergency use process, improving the practicality and safety of the fire hydrant, especially in emergency situations where it can be quickly opened or closed.

[0017] Optionally, the valve seat includes a valve plate, a gasket, and a bolt. The valve plate is fixed to the end of the valve stem by the bolt. The gasket is disposed between the valve plate and the nut of the bolt. The bolt has a through hole along its central axis and communicates with the pressure channel.

[0018] By adopting the above technical solution, the valve plate is fixed by bolts, and the gasket provides additional sealing to prevent water leakage; the through hole in the central axis of the bolt is connected to the pressure channel to ensure that the water pressure is smoothly transmitted to the valve seat, making the valve plate more sensitive to opening and closing; this structure is simple and reliable, improves the sealing performance and pressure resistance of the valve seat, and reduces the frequency of maintenance.

[0019] Optionally, a sealing groove is provided at the connection between the spring cavity, the valve body extension seat and the valve body 4, and a sealing ring is provided in the sealing groove.

[0020] By adopting the above technical solution, the sealing ring is embedded in the sealing groove, which effectively prevents water leakage at the connection and ensures that the fire hydrant remains completely sealed under high pressure. This design enhances the overall waterproofness and durability, reduces water waste or equipment failure caused by leakage, and improves the adaptability of the fire hydrant in harsh environments.

[0021] Optionally, the top of the spring cavity is provided with a removable valve cover, and the top of the spring pressure plate is provided with a nut that is threadedly connected to the spring guide rod, which is used to provide downward support force for the spring pressure plate to adjust the spring tension.

[0022] By adopting the above technical solution, the valve cover provides easy access to the internal adjustment components, facilitating daily inspection or spring replacement; the nut is threaded to the valve stem, allowing adjustment of the spring pressure plate position, thereby precisely controlling the spring tension to adapt to different water pressure conditions; this design improves the adjustability and maintenance convenience of the fire hydrant, ensuring optimized performance during long-term operation.

[0023] In summary, this application includes at least one of the following beneficial technical effects: 1. When water flows into the cavity from the pressure channel, it compresses the piston and, in conjunction with the tension of the adjusting component spring, automatically slides up and down according to water pressure changes. This achieves a dynamic balance between the cavity pressure and spring tension, allowing for adaptive adjustment without manual intervention. This maintains stable valve control, preventing damage to equipment due to excessively high or low inlet pressure, or significant inconvenience to firefighting operations due to unstable outlet pressure. It ensures that firefighters have a safe, stable, and controllable water source regardless of fluctuations in the pipeline pressure. 2. The multi-channel pressure-diverting system inside the valve stem ensures uniform piston force and smooth operation; the optimized layout of the outlet and inlet improves the water flow path and reduces pressure loss; and the meticulous design of the valve seat and sealing ring greatly enhances the overall sealing performance and prevents leakage. These structural improvements work together to result in a more balanced water flow distribution inside the fire hydrant, smoother component movement, stronger wear resistance and pressure resistance, and a substantial improvement in overall performance. 3. By employing a removable valve cover, adjustable spring tension via a nut, and a snap-lock cap, this fire weir greatly facilitates daily inspection, maintenance, and component replacement. The adjustable spring preload allows it to flexibly adapt to different on-site water pressure environments. This design, emphasizing maintainability and adaptability, not only reduces overall lifecycle maintenance costs but also better meets diverse practical application needs. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of a fire hydrant; Figure 2 This is a cross-sectional view of a fire hydrant. Figure 3 yes Figure 2 An enlarged schematic diagram of part A in the middle; Figure 4 yes Figure 2 Enlarged schematic diagram of part B in the middle; In the picture, 1. Spring cavity; 2. Adjustment assembly; 21. Spring; 22. Spring guide rod; 23. Spring pressure plate; 3. Valve body extension seat; 31. Cavity; 32. Piston; 33. Valve stem; 34. Pressure tapping channel; 341. Main channel; 342. Branch channel; 4. Valve body; 41. Inlet chamber; 42. Valve seat; 421. Valve plate; 422. Gasket; 423. Bolt; 4231. Through hole; 43. Outlet; 431. Water pipe connector; 432. End cap; 44. Inlet. 5. Sealing groove; 51. Sealing ring; 6. Valve cover; 7. Nut. Detailed Implementation

[0025] The following is in conjunction with the appendix Figure 1 - Appendix Figure 4 This application will be described in further detail below.

[0026] A type of fire hydrant, referring to Figure 1 and Figure 2 The fire hydrant includes a spring cavity 1, a valve body extension seat 3, and a valve body 4, which are connected sequentially from top to bottom. This connection method makes the entire fire hydrant structure compact and functionally organized. The spring cavity 1 contains an adjusting assembly 2, which includes a spring 21 and a spring pressure plate 23. The spring 21 continuously provides tension, i.e., an upward elastic force, to the spring pressure plate 23. The spring pressure plate 23 can slide up and down in the spring cavity 1 according to changes in water pressure. The valve body extension seat 3 contains a cavity 31, a piston 32, and a valve stem 33. The piston 32 is fixed to the valve stem 33. One end of the valve stem 33 is fixedly connected to the adjusting assembly 2, forming an integral long rod, and the other end passes through the bottom of the valve body extension seat 3 and extends into the valve body 4. The valve body 4 has an inlet chamber 41, an inlet 44, and an outlet 43. A valve seat 42 is located at the connection between the inlet chamber 41 and the inlet 44. The valve seat 42 controls the inflow and outflow of water and is fixedly connected to the extension of the valve stem 33. A pressure-inducing channel 34 is provided inside the valve stem 33 to supply water. The pressure-inducing channel 34 connects the valve body 4 and the cavity 31, allowing water to flow into the cavity 31 and then press down on the piston 32.

[0027] When water enters the valve body 4 from below the valve seat 42, it flows into the cavity 31 through the pressure channel 34. The cavity 31 fills with water and continues to increase. The increase in water in the cavity 31 exerts a downward squeezing force on the piston 32. The squeezing force overcomes the upward elastic force of the spring 21 and the upward impact force of the water on the valve seat 42. Finally, the valve seat 42, valve stem 33, and regulating component 2 tend to stabilize, achieving a dynamic balance of forces. At this time, the opening of the valve seat 42 relative to the inlet 44 remains relatively stable, and both the inlet and outlet water become stable. However, when the inlet water flow suddenly increases, the upward impact force of the water on the valve seat 42 also increases, and the water flowing into the pressure channel 34 also increases accordingly. The downward squeezing force of the water on the piston 32 also increases. Even if the valve seat moves upward due to the impact of the water, the opening of the valve seat 42 will not increase too quickly, and it will soon return to a relatively stable state. The amount of inlet and outlet water will not change suddenly. Conversely, when the water flow rate suddenly decreases, the upward force of the water on the valve seat 42 also decreases, and the water flowing into the pressure channel 34 also decreases accordingly. This reduces the downward pressure of the water on the piston 32. Since the spring 21 maintains an upward tension on the spring plate 23, this tension is greater than the downward pressure of the water on the piston 32, preventing the valve seat 42 from closing too quickly. This self-adjusting valve seat requires no manual intervention, maintaining stable valve control and preventing damage to equipment due to excessively high or low inlet pressure, or significant inconvenience to firefighting operations due to unstable water pressure at the outlet 43. It ensures that firefighters have a safe, stable, and controllable water source regardless of fluctuations in the pipeline pressure.

[0028] Furthermore, refer to Figure 2 The adjusting assembly 2 inside the spring cavity 1 also includes a spring guide rod 22. A spring 21 is fitted onto the spring guide rod 22. The spring 21 has a certain degree of elasticity and is typically made of high-strength spring steel, which ensures that the spring 21 maintains good elasticity and stability during long-term use. Both ends of the spring 21 are fixedly connected to the bottom of the inner cavity of the spring cavity 1 and the spring pressure plate 23, respectively. The spring pressure plate 23 is fixedly connected to the spring guide rod 22. The spring guide rod 22 passes through the bottom of the spring cavity 1 and is fixedly connected to the valve stem 33. The connection point can be formed by an internal threaded hole inside the connection between the spring guide rod 22 and the valve stem 33, and then screwed together to form a long rod. The spring guide rod 22 guides the extension and retraction direction of the spring 21. It is cylindrical in shape with a smooth surface to reduce friction with the spring 21. The spring pressure plate 23 is used to fix one end of the spring 21 and transmits force when the spring 21 extends or retracts. The spring pressure plate 23 can be a circular metal plate, which is fixed to the spring guide rod 22 by welding or bolt 423.

[0029] Spring 21 provides upward tension to spring plate 23, which can slide up and down according to changes in water pressure. When the water pressure changes, spring 21 will extend or retract accordingly, thereby moving spring plate 23. In some cases, spring 21 can also be replaced by a component with similar elastic function, such as an elastic rubber column.

[0030] Furthermore, refer to Figure 2 The piston 32 inside the valve body extension seat 3 is fixed to the valve stem 33. The piston 32 is generally cylindrical, and its surface is finely machined to ensure good sealing with the inner wall of the cavity 31. The piston 32 can be made of wear-resistant rubber material or a structure with a metal surface covered with rubber. One end of the valve stem 33 is fixedly connected to the spring guide rod 22, and the other end extends through the valve body extension seat 3 into the valve body 4 and is fixedly connected to the valve seat 42. The valve stem 33 is usually made of metal, such as stainless steel, which has high strength and corrosion resistance.

[0031] The piston 32 and valve stem 33 can be fixed by having a recessed groove on the lower surface where the piston 32 and valve stem 33 connect, while the corresponding valve stem 33 has a protruding engaging part. This allows the groove of the piston 32 to engage with the engaging part, restricting the downward movement of the piston 32. At the same time, a retaining ring is provided on the upper surface where the piston 32 and valve stem 33 connect. The retaining ring is fixedly connected to the valve stem 33, and the lower surface of the retaining ring abuts against the piston 32, thus limiting the upward movement of the piston 32. The groove and the retaining ring cooperate with each other to fix the piston 32 to the valve stem 33.

[0032] Furthermore, refer to Figure 3 The pressure-inducing channel 34 within the valve stem 33 includes a main channel 341 and branch channels 342. The main channel 341 is located on the central axis of the valve stem 33, and the branch channels 342 connect the main channel 341 and the cavity 31. Multiple branch channels 342 are provided and evenly distributed circumferentially along the valve stem 33. This design allows water to enter the cavity 31 evenly, generating stable pressure on the piston 32. The main channel 341 and branch channels 342 can be machined within the valve stem 33 by drilling. In certain special cases, the pressure-inducing channel 34 can also achieve the same function by connecting to an external pipe.

[0033] Furthermore, refer to Figure 2 and Figure 4The valve body 4 has an inlet chamber 41, and the valve seat 42 is located at the connection between the inlet chamber 41 and the inlet 44 to control the inflow of water. The valve seat 42 includes a valve plate 421, a gasket 422, and a bolt 423. The upper surface of the valve plate 421 has a groove that can be fitted onto the end of the valve stem 33. The bolt 423 passes through the lower surface of the valve plate 421 and is threadedly connected to the end of the valve stem 33, fixing the valve plate 421 to the end of the valve stem 33. The gasket 422 is located between the valve plate 421 and the nut of the bolt 423. A washer that is usually matched with the bolt is also placed between the nut of the bolt 423 and the gasket 422. This can increase the pressure area and reduce the local pressure when the bolt is tightened, thus ensuring the service life of the parts. The bolt 423 has a through hole 4231 on its central axis, which communicates with the pressure channel 34 to form a smooth water flow channel. The valve plate 421 is typically a circular metal plate with a smooth surface, which fits tightly with the opening of the inlet chamber 41 to achieve effective control of the water flow. The gasket 422 serves as a seal and buffer, and can be made of materials such as rubber or asbestos. The bolt 423 is used to fix the valve plate 421, and its through hole 4231 allows water to enter the cavity 31 through the pressure channel 34.

[0034] Furthermore, refer to Figure 2 The inlet 44 is located at the bottom of the valve body 4, and the outlet 43 is located on the side wall of the valve body 4. The inlet 44, the inlet chamber 41, and the outlet 43 form a connected water flow channel. This arrangement conforms to the flow law of water, allowing water to smoothly enter and exit the valve body 4.

[0035] Furthermore, the water outlet 43 is equipped with a cap 432 and a water pipe connector 431. The water pipe connector 431 connects to the water outlet 43, and the cap 432 and the water pipe connector 431 are detachably connected by a locking mechanism. The water pipe connector 431 can be a Storz connector, a German-style self-locking quick connector mainly used for quick connections in fire-fighting equipment, industrial pipelines, and other scenarios. The connection method is locking / unlocking by rotating 90°, without the need for threading. When not in use, the cap 432 prevents debris from entering the water outlet 43, ensuring the cleanliness and unobstructed flow of the water outlet 43. When needed, the cap 432 is opened via the locking mechanism, and the external water hose nozzle is connected to the water pipe connector 431 for fire extinguishing operations. The locking mechanism can be a common snap-on type or a threaded connection type, allowing the cap 432 to be securely and tightly sealed to the water pipe connector 431. Meanwhile, the cap 432 is connected to the valve body 4 by an iron chain, which allows the cap 432 to be removed when the fire hydrant is in use. The cap 432 can be firmly fastened to the valve body 4 to prevent loss, or it can be convenient to put it back on after the fire hydrant is used.

[0036] Furthermore, sealing grooves 5 are provided at the connection points of the spring cavity 1, valve body extension seat 3, and valve body 4, and sealing rings 51 are installed inside the sealing grooves 5. The sealing rings 51 are generally made of rubber material, which has good elasticity and sealing performance, and can prevent water from leaking from the connection points. At the same time, sealing grooves 5 are provided at the places where the long rod formed by the spring guide rod 22 and the valve rod 33 passes through the spring cavity 1 and the valve body extension seat 3, as well as at the contact point between the piston 32 and the inner wall of the valve body extension seat 3. Sealing rings 51 are installed inside the sealing grooves 5, which can maintain the sealing of the entire device when the long rod moves up and down, preventing mutual leakage and also preventing water from entering the other two cavities from the valve body 4.

[0037] Furthermore, refer to Figure 2 A removable valve cover 6 is provided on the top of the spring cavity 1, and the valve cover 6 is sealed to the top of the spring cavity 1. A nut 7 is provided above the spring pressure plate 23 and threadedly connected to the valve stem 33. The nut 7 provides downward support force to the spring pressure plate 23 to adjust the tension of the spring 21. By rotating the nut 7, the preload of the spring 21 can be changed, thereby adjusting the outlet pressure of the fire hydrant. When the outlet 43 requires a larger water flow, the opening of the valve body 4 to the inlet 44 needs to be increased. At this time, the valve cover 6 is opened, and by turning the nut 7 upward, the spring 21 will push the spring pressure plate 23 upward, thereby causing the valve seat 42 to move upward, and the opening of the inlet 44 will also increase. At this time, the flow rate corresponding to the outlet 43 will also increase. Conversely, turning the nut 7 downward will reduce the opening of the inlet 44, and the flow rate corresponding to the outlet 43 will also decrease.

[0038] The implementation principle of this embodiment is as follows: When the inlet pressure increases, water enters the cavity 31 through the pressure channel 34, generating downward pressure on the piston 32. This pressure overcomes the elastic force of the spring 21, forcing the valve seat 42 to move downward, reducing the valve body 4 opening, and increasing the pressure reduction capacity, thereby maintaining stable downstream pressure. Conversely, when the inlet pressure decreases, the pressure inside the cavity 31 decreases, and the valve seat 42 moves upward under the action of the spring 21, increasing the valve body 4 opening, reducing the pressure reduction capacity, and similarly maintaining stable downstream pressure. The downstream pressure is determined by the tightness of the spring 21 and the top bolt 423. The tighter the spring 21, the higher the tightness, and the greater the downstream pressure. Furthermore, the downstream pressure does not change with the inlet pressure. This adaptive adjustment method requires no manual intervention and can effectively cope with fluctuations in pipeline pressure, providing firefighters with a safe, stable, and controllable water source. Compared to traditional fire hydrants, it greatly improves the efficiency and safety of firefighting operations.

[0039] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be included within the scope of protection of this application.

Claims

1. A fire hydrant, characterized in that, It includes a spring cavity (1), a valve body extension seat (3) and a valve body (4) connected sequentially from top to bottom; The spring cavity (1) is provided with an adjustment component (2), which includes a spring (21) and a spring pressure plate (23). The spring (21) is used to provide tension to the spring pressure plate (23). The valve body extension seat (3) is provided with a cavity (31), a piston (32) and a valve stem (33). The piston (32) is fixed on the valve stem (33). One end of the valve stem (33) is fixedly connected to the adjustment assembly (2), and the other end extends through the valve body extension seat (3) into the valve body (4). The valve stem (33) is provided with a pressure channel (34), which connects the valve body (4) and the cavity (31) to guide water into the cavity (31) and squeeze the piston (32). The valve body (4) is provided with an inlet chamber (41), an inlet (44), an outlet (43) and a valve seat (42). The valve seat (42) is located at the connection between the inlet chamber (41) and the inlet (44). The valve seat (42) is used to control the inlet and outlet of water. The valve seat (42) is fixedly connected to the extension of the valve stem (33).

2. A fire hydrant according to claim 1, characterized in that, The adjustment assembly (2) further includes a spring guide rod (22), the spring (21) is sleeved on the spring guide rod (22), the two ends of the spring (21) are fixedly connected to the bottom of the inner cavity of the spring cavity (1) and the spring pressure plate (23) respectively, the spring pressure plate (23) is fixedly connected to the spring guide rod (22), and the spring guide rod (22) passes through the bottom of the spring cavity (1) and is fixedly connected to the valve stem (33).

3. A fire hydrant according to claim 1, characterized in that, The pressure channel (34) includes a main channel (341) and a branch channel (342). The main channel (341) is located on the central axis of the valve stem (33), and the branch channel (342) connects the main channel (341) and the cavity (31).

4. A fire hydrant according to claim 3, characterized in that, The diversion channel (342) is provided in multiple ways and is evenly distributed around the valve stem (33).

5. A fire hydrant according to claim 1, characterized in that, The inlet (44) is located at the bottom of the valve body (4), and the outlet (43) is located on the side wall of the valve body (4). The inlet (44), the inlet chamber (41), and the outlet (43) form a connected water flow channel.

6. A fire hydrant according to claim 5, characterized in that, The outlet (43) is provided with a cap (432) and a water pipe connector (431). The water pipe connector (431) is connected to the outlet (43). The cap (432) and the water pipe connector (431) are detachably connected by a locking buckle.

7. A fire hydrant according to claim 1, characterized in that, The valve seat (42) includes a valve plate (421), a gasket (422) and a bolt (423). The valve plate (421) is fixed to the end of the valve stem (33) by the bolt (423). The gasket (422) is disposed between the valve plate (421) and the nut of the bolt (423). The bolt (423) has a through hole (4231) on its central axis and communicates with the pressure channel (34).

8. A fire hydrant according to claim 1, characterized in that, The connection between the spring cavity (1), the valve body extension seat (3) and the valve body (4) is provided with a sealing groove (5), and a sealing ring (51) is provided in the sealing groove (5).

9. A fire hydrant according to claim 2, characterized in that, The top of the spring cavity (1) is provided with a removable valve cover (6), and the top of the spring pressure plate (23) is provided with a nut (7) that is threadedly connected to the spring guide rod (22) to provide downward support force for the spring pressure plate (23) to adjust the tension of the spring (21).

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