Plunger type safety valve for railway air braking system

Abstract

The invention relates to the technical field of safety valves, aims to solve the problems that a valve and a valve seat in an existing safety valve are sealed through a metal grinding face, the sealing effect becomes poor after long-term use, and leakage is prone to occurring, and provides a plunger type safety valve for a railway air braking system. The mounting seat is communicated with the volume chamber, and the pressure of the volume chamber can enter the mounting seat; the mounting seat is also communicated with the atmosphere; a safety valve opening component is arranged in the mounting seat, a pre-pressing component is arranged in the valve body, the pre-pressing component is used for applying pre-pressure, the pre-pressure acts on one side of the safety valve opening component, and the pressure of the volume chamber acts on the other side of the safety valve opening component; the safety valve opening component can move under the combined action of the pre-pressure and the pressure of the volume chamber so as to connect or disconnect an air path between the volume chamber and the atmosphere; and a sealing ring is arranged on the sealing surface of the safety valve opening component.

Description

Technical Field

[0001] The invention relates to the technical field of safety valves, and in particular to a plunger type safety valve for a railway air brake system. Background Art

[0002] Safety valves are usually protective devices for the maximum pressure limit of pressure vessels. Under normal circumstances, they are in a closed state, closing the passage between the pressure vessel and the outside world; when the pressure inside the pressure vessel exceeds the set value, the safety valve opens the passage between the pressure vessel and the outside world, allowing the pressure inside the pressure vessel to be discharged to the atmosphere, reducing the pressure value inside the container.

[0003] In the air brake system of large railway track maintenance machinery or locomotives, the safety valve is used to limit the maximum pressure of the volume chamber, and then the brake cylinder pressure is controlled through the action valve of the distribution valve balance part (the pressure of the volume chamber is approximately equal to the pressure of the brake cylinder). According to the requirements of the brake system, during emergency braking, the maximum pressure of the brake cylinder is 450±10kPa; during fire return, the pressure of the brake cylinder is 200~250kPa. Both working conditions require the safety valve to be adjusted to make the pressure of the volume chamber (brake cylinder) meet the requirements.

[0004] The main problems of existing safety valves are:

[0005] The key components of existing safety valves are the valve and the valve seat, both of which are made of metal. The contact surface between the two constitutes the sealing surface, which controls the flow of gas between the volume chamber and the atmosphere. Since the sealing method is a metal-to-metal seal, a special grinding process is required for the sealing surface to ensure the sealing performance. This sealing method is usually called a metal grinding surface seal. Figure 1 shown.

[0006] When the pressure in the volume chamber is greater than the set pressure (spring force), the valve overcomes the spring force and moves upward, while the valve seat remains stationary, a certain gap appears between the sealing surfaces of the two, the passage between the volume chamber and the atmosphere is opened, the pressure in the volume chamber is discharged from the open sealing surface to the atmosphere, and the pressure in the volume chamber and the brake cylinder is reduced; when the pressure in the volume chamber is less than the set pressure (spring force), the valve and the valve seat are in close contact at the sealing surface, the passage between the volume chamber and the atmosphere is disconnected, and the pressure in the volume chamber and the brake cylinder remains unchanged.

[0007] During the exhaust process of the safety valve, the sealing surface between the valve and the valve seat repeatedly opens and closes, constantly adjusting the relationship between the volume chamber pressure and the spring force until the two are balanced. Due to the continuous collision of the metal sealing surface, after a period of use, the sealing surface will be damaged and dented, and the sealing effect will weaken, causing the volume chamber pressure to slowly discharge into the atmosphere, and the brake cylinder pressure will decrease until it reaches zero. This does not meet the technical requirements and will affect driving safety. In addition, the grinding of the valve and valve seat sealing surface requires special tooling and equipment. Once the grinding is not well matched, leakage will occur and re-grinding is required. The production process is labor-intensive and time-consuming, affecting production efficiency. Summary of the invention

[0008] The present invention aims to provide a plunger type safety valve for railway air brake system, so as to solve the problem that the existing safety valve adopts metal grinding surface sealing between the valve and the valve seat, the sealing effect deteriorates after long-term use, and leakage easily occurs.

[0009] The present invention is achieved by adopting the following technical solutions:

[0010] The present invention provides a plunger type safety valve for a railway air brake system, comprising a valve body and a mounting seat, wherein the valve body is connected to the mounting seat, the mounting seat is connected to a volume chamber, and the pressure of the volume chamber can enter the mounting seat; the mounting seat is also connected to the atmosphere;

[0011] A safety valve opening component is arranged in the mounting seat, and a pre-pressure component is arranged in the valve body, and the pre-pressure component is used to apply pre-pressure, the pre-pressure acts on one side of the safety valve opening component, and the volume chamber pressure acts on the other side of the safety valve opening component;

[0012] The safety valve opening component can move under the combined action of the pre-pressure and the volume chamber pressure, thereby connecting or disconnecting the gas path between the volume chamber and the atmosphere;

[0013] A sealing ring is arranged on the sealing surface of the safety valve opening component.

[0014] The valve body of the present invention is provided with a pre-pressure component, which applies pre-pressure to the safety valve opening component. When the pressure in the volume chamber is less than the pre-pressure, the safety valve opening component disconnects the gas path between the volume chamber and the atmosphere, and the safety valve will not open; when the pressure in the volume chamber is greater than the pre-pressure, the safety valve opening component overcomes the pre-pressure applied by the pre-pressure component and moves, and the safety valve opening component communicates the gas path between the volume chamber and the atmosphere, and the safety valve opens. The function of the safety valve is realized through the above structure.

[0015] Regarding the sealing ring, on the one hand, when the safety valve opening component disconnects the gas path between the volume chamber and the atmosphere, the sealing ring plays a sealing role to avoid air leakage; on the other hand, when the safety valve opening component moves in the mounting seat, the sealing ring makes sliding contact with the sealing position. Due to the good wear resistance and sealing performance of the sealing ring, it has little wear after long-term use and can still meet the sealing requirements, solving the leakage problem of the metal grinding surface sealing structure after long-term use, ensuring the sealing of the volume chamber pressure, extending the service life of the safety valve, and improving driving safety. Moreover, compared with the grinding process of the metal sealing surface, the use of the sealing ring reduces the production difficulty and improves the production efficiency.

[0016] As the preferred technical solution:

[0017] The mounting seat is connected to the valve body via threads.

[0018] As the preferred technical solution:

[0019] A plurality of screws are connected between the mounting seat and the valve body for further fixing the mounting seat and the valve body.

[0020] As the preferred technical solution:

[0021] The mounting seat is provided with a concave cavity, the safety valve opening component is located in the concave cavity, and the safety valve opening component can move up and down in the concave cavity.

[0022] As the preferred technical solution:

[0023] A primary cavity is arranged on the upper part of the mounting seat, a secondary cavity is arranged at the bottom of the primary cavity, the primary cavity is communicated with the secondary cavity, and a plunger sleeve is installed in the secondary cavity;

[0024] The safety valve opening component includes a piston rod and a piston, and the piston is connected to one end of the piston rod; the piston rod is located in the plunger sleeve, and the piston is located in the primary concave cavity. The piston rod is slidably connected to the plunger sleeve, and the sealing ring is sleeved on the piston rod, and the sealing ring is slidably connected to the plunger sleeve.

[0025] With the above structure, the piston rod can move up and down in the plunger sleeve, the piston can move up and down in the primary cavity, and the piston rod and the piston move synchronously.

[0026] As the preferred technical solution:

[0027] The primary cavity and the secondary cavity are cylindrical cavities.

[0028] It is convenient to match the shapes of the piston and the plunger sleeve.

[0029] As the preferred technical solution:

[0030] However, the shapes of the primary cavity and the secondary cavity are not limited to cylindrical cavities, as long as they match the shapes of the piston and the plunger sleeve.

[0031] As the preferred technical solution:

[0032] The plunger sleeve is pressed into the secondary concave cavity of the mounting seat, and the position of the plunger sleeve remains stationary.

[0033] As the preferred technical solution:

[0034] The upper end of the piston rod is arranged as an insertion end, the insertion end passes through the middle part of the piston, and a nut is connected to the insertion end, and the piston and the piston rod are fixedly connected together by the nut.

[0035] As the preferred technical solution:

[0036] The pre-pressing component is an elastic telescopic component, and the telescopic direction of the elastic telescopic component is perpendicular to the upper surface of the piston.

[0037] With the above structure, the pre-pressure applied by the pre-pressure component acts on the upper surface of the piston, and the pre-pressure component applies a downward force to the piston.

[0038] As the preferred technical solution:

[0039] One end of the elastic telescopic component abuts against the piston, and the other end of the elastic telescopic component abuts against the pressure regulating component, and the pressure regulating component is connected to the valve body.

[0040] By changing the position of the pressure regulating component on the valve body, the compression amount of the elastic telescopic component is adjusted, the pre-pressure of the elastic telescopic component is adjusted, and the pressure in the volume chamber is controlled. The function of a safety valve is achieved, and the requirements for the use of safety valves by large-scale road maintenance machinery or locomotives are met.

[0041] As the preferred technical solution:

[0042] The elastic telescopic component is a spring, and the spring is sleeved on a positioning rod, and one end of the positioning rod abuts against the piston.

[0043] The positioning rod is used to control the compression or extension direction of the spring to prevent the spring from twisting and deforming, thereby affecting the elastic force of the spring, namely the above-mentioned preload.

[0044] As the preferred technical solution:

[0045] However, the elastic telescopic component is not limited to a spring, and other components with elastic telescopic capabilities may also be used, such as an elastic rubber strip.

[0046] As the preferred technical solution:

[0047] The pressure regulating component adopts an adjusting nut, and the adjusting nut is connected to the valve body through threads, so that the position of the adjusting nut on the valve body can be easily adjusted to change the compression amount of the spring.

[0048] As the preferred technical solution:

[0049] However, the pressure regulating component is not limited to the adjusting nut, and other components that can change position on the valve body may also be used. The connection with the valve body is not limited to a threaded connection, and may also be a sliding connection, etc.

[0050] As the preferred technical solution:

[0051] A rotating washer is installed between the adjusting nut and the spring, and the rotating washer is used to prevent the spring from being twisted when the adjusting nut is rotated and the spring is driven to rotate.

[0052] As the preferred technical solution:

[0053] The lower end of the valve body is inserted into the primary concave cavity of the mounting seat and connected to the mounting seat. At this time, the valve body can limit the upper limit position of the piston. When the upper surface of the piston contacts the valve body, the piston moves up to the limit position.

[0054] As the preferred technical solution:

[0055] A positioning component is connected to the upper portion of the pressure regulating component, and the positioning component is used to position the pressure regulating component after it is adjusted to a target position.

[0056] As the preferred technical solution:

[0057] The positioning component is a nut, the nut is connected to the adjusting nut through threads, and the nut and the valve body jointly fix the adjusting nut to prevent the adjusting nut from rotating and affecting the acting force of the spring.

[0058] As the preferred technical solution:

[0059] However, the positioning component is not limited to the nut, and other components that can be connected to the adjusting nut may also be used to cooperate with the valve body to fix the adjusting nut.

[0060] As the preferred technical solution:

[0061] A volume chamber communicating hole is provided on the mounting seat, one end of the volume chamber communicating hole is communicated with the volume chamber, the other end of the volume chamber communicating hole is communicated with the primary concave cavity, and the volume chamber communicating hole is arranged opposite to the lower surface of the piston.

[0062] With the above structure, the pressure in the volume chamber acts on the piston from the lower surface of the piston, exerting an upward force on the piston.

[0063] As the preferred technical solution:

[0064] A guide groove is arranged at the lower part of the adjusting nut, and the upper end of the spring extends into the guide groove and abuts against the adjusting nut.

[0065] As the preferred technical solution:

[0066] The mounting seat is provided with a first side hole, the first side hole being connected to the volume chamber communication hole;

[0067] A second side hole is opened in the radial direction of the plunger sleeve, the second side hole corresponds to the position of the first side hole, and the first side hole is connected to the second side hole;

[0068] The piston rod is provided with an exhaust hole, and when the piston moves upward, the exhaust hole is connected with the second side hole and the first side hole;

[0069] A pressure relief hole is provided on the mounting seat, the pressure relief hole is connected to the atmosphere, and the exhaust hole is connected to the pressure relief hole.

[0070] As the preferred technical solution:

[0071] The exhaust hole includes a third side hole opened in the radial direction of the piston rod and a vertical exhaust hole opened in the lower part of the piston rod, one end of the vertical exhaust hole is connected to the third side hole, the other end of the vertical exhaust hole is connected to the secondary concave cavity, and the vertical exhaust hole is connected to the pressure relief hole.

[0072] When the pressure in the volume chamber is greater than the set pressure, the pressure in the volume chamber causes the piston to drive the piston rod to move upward, and the third side hole on the piston rod is connected with the second side hole and the first side hole. The pressure in the volume chamber enters the volume chamber connecting hole, and then passes through the first side hole, the second side hole, the third side hole, the vertical exhaust hole, and the pressure relief hole in sequence to realize the gas path connecting the volume chamber and the atmosphere, and is discharged to the atmosphere through the pressure relief hole. When the exhaust is completed, the piston will move downward under the action of the pre-pressing component, and the piston rod will move downward accordingly. The third side hole on the piston rod is staggered with the second side hole, and the two are not connected. At this time, no pressure relief and exhaust occurs.

[0073] As the preferred technical solution:

[0074] The lower outer side of the piston rod is sleeved with a first sealing ring and a second sealing ring, the first sealing ring and the second sealing ring are respectively located on the upper side and the lower side of the third side hole, and the first sealing ring and the second sealing ring are in sealing contact with the plunger sleeve.

[0075] The upper and lower sides of the third side hole are respectively sealed by a first sealing ring and a second sealing ring, so no air leakage occurs.

[0076] As the preferred technical solution:

[0077] A third sealing ring is sleeved on the outer side of the piston, and the third sealing ring is in sealing contact with the mounting seat;

[0078] A fourth sealing ring is sleeved on the outer side of the upper portion of the piston rod, and the fourth sealing ring is in sealing contact with the piston.

[0079] The third sealing ring and the fourth sealing ring play a sealing role to prevent the pressure in the volume chamber from leaking to the atmosphere from the piston rod and the piston.

[0080] As the preferred technical solution:

[0081] A fifth sealing ring is installed between the mounting seat and the volume chamber, and the fifth sealing ring is used to prevent the pressure in the volume chamber from leaking to the atmosphere from the mounting position of the safety valve.

[0082] As the preferred technical solution:

[0083] A fourth side hole is provided on the side wall of the mounting seat, a screw plug is installed in the fourth side hole, and the screw plug is a process plug and plays a sealing role.

[0084] As the preferred technical solution:

[0085] Each sealing ring is an O-ring.

[0086] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0087] 1. The safety valve of the present invention replaces the original metal grinding surface sealing structure with a sealing ring, which ensures the reliability of the seal and eliminates the leakage problem caused by the long-term use of the metal grinding surface seal. The seal ring has good wear resistance and sealing performance, and has little wear after long-term use. It can still meet the sealing requirements and ensure the sealing of the volume chamber pressure. Moreover, compared with the grinding process of the metal sealing surface, the use of the sealing ring reduces the production difficulty and improves the production efficiency. The sealing ring is easy to install and replace, and the operation is convenient.

[0088] 2. The present invention newly designs a plunger-type safety valve, which applies pre-pressure to the safety valve opening component (piston and piston rod) through a pre-pressure component (spring). Only when the safety valve opening component is subjected to a larger volume chamber pressure and overcomes the pre-pressure of the pre-pressure component, the safety valve will open to communicate the gas path between the volume chamber and the atmosphere, thereby achieving exhaust and pressure relief.

[0089] 3. The safety valve of the present invention is designed with a pressure regulating component. By changing the position of the pressure regulating component on the valve body, the compression amount of the elastic telescopic component is adjusted, the pre-pressure of the elastic telescopic component is adjusted, and the pressure in the volume chamber is controlled. It has the function of a safety valve, meets the application requirements of large-scale road maintenance machinery or locomotives for safety valves, and ensures the safe operation of large-scale road maintenance machinery or locomotives.

[0090] 4. The present invention has a simple design, compact structure, and the various parts involved are easy to obtain and low in cost. At the same time, the pressure relief effect is good, the pressure is controllable, and the application range is wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 The present invention is a schematic structural diagram of a plunger-type safety valve for a railway air brake system in a closed position.

[0092] Figure 2 for Figure 1 A magnified schematic diagram of center A.

[0093] Figure 3 for Figure 1 Schematic diagram of the forces at work.

[0094] Figure 4 The internal schematic diagram of the plunger-type safety valve for the railway air brake system of the present invention is in the open position.

[0095] Figure 5 for Figure 4 Schematic diagram of the forces at work.

[0096] Figure 6 The figure is a top view of the plunger type safety valve for the railway air brake system according to the present invention.

[0097] Icons: 1- nut, 2- adjusting nut, 3- rotating washer, 4- spring, 5- valve body, 6- screw, 7- nut, 8- third sealing ring, 9- fourth sealing ring, 10- piston rod, 11- first sealing ring, 12- mounting seat, 13- fifth sealing ring, 14- plunger sleeve, 15- screw plug, 16- piston, 17- positioning rod, 18- second sealing ring, 19- pressure relief hole, 20- volume chamber connecting hole, 21- first side hole, 22- second side hole, 23- third side hole, 24- vertical exhaust hole, 25- first concave cavity, 26- second concave cavity, 27- step surface. DETAILED DESCRIPTION

[0098] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0099] Example 1

[0100] like Figure 1-Figure 6 As shown, this embodiment provides a plunger type safety valve for a railway air brake system, comprising a valve body 5 and a mounting seat 12, wherein the bottom of the mounting seat 12 is used to be connected to a volume chamber.

[0101] A primary cavity 25 is disposed on the upper portion of the mounting seat 12 , a secondary cavity 26 is disposed at the bottom of the primary cavity 25 , the primary cavity 25 is communicated with the secondary cavity 26 , and a step surface 27 is formed between the primary cavity 25 and the secondary cavity 26 .

[0102] In this embodiment, the primary cavity 25 and the secondary cavity 26 are cylindrical cavities.

[0103] The plunger sleeve 14 is installed in the secondary cavity 26. In this embodiment, the plunger sleeve 14 is pressed onto the mounting seat 12 and its position remains unchanged.

[0104] The piston sleeve 14 is provided with a piston rod 10, and the piston rod 10 is slidably connected to the piston sleeve 14. The upper end of the piston rod 10 is connected to a piston 16, and the piston 16 is located outside the plunger sleeve 14. The piston 16 is located in the primary concave cavity 25 and is adapted to the primary concave cavity 25. The piston 16 and the piston rod 10 can move up and down together.

[0105] In this embodiment, the piston rod 10 and the piston 16 are connected in the following manner: the upper end of the piston rod 10 is set as an insertion end, the insertion end passes through the middle of the piston 16, and a nut 7 is connected to the insertion end, and the piston 16 and the piston rod 10 are fixedly connected together by the nut 7. The nut 7 is an M8 nut.

[0106] A pressure relief hole 19 is provided on one side of the mounting seat 12 , one end of the pressure relief hole 19 is connected to the secondary cavity 26 , and the other end of the pressure relief hole 19 is connected to the atmosphere.

[0107] The lower part of the mounting seat 12 is provided with a volume chamber communication hole 20, one end of which is connected to the volume chamber, and the pressure of the volume chamber can enter the volume chamber communication hole 20. The other end of the volume chamber communication hole 20 is connected to the primary concave cavity 25, and the volume chamber communication hole 20 is opposite to the lower surface of the piston 16, so the pressure of the volume chamber can push the piston 16 to move upward, and the piston rod 10 moves upward in the plunger sleeve 14 accordingly.

[0108] The upper portion of the mounting seat 12 is connected to the valve body 5. In the present embodiment, the mounting seat 12 and the valve body 5 are connected via threads. Furthermore, a plurality of screws 6 are connected between the mounting seat 12 and the valve body 5 for further fixing the mounting seat 12 and the valve body 5. The screws 6 are M5 screws.

[0109] The lower end of the valve body 5 is inserted into the primary concave cavity 25 of the mounting seat 12 and connected to the mounting seat 12. At this time, the valve body 5 can limit the upper limit position of the piston 16. When the upper surface of the piston 16 contacts the valve body 5, the piston 16 moves up to the limit position.

[0110] A positioning rod 17 is provided inside the valve body 5, and the lower end of the positioning rod 17 abuts against the upper surface of the piston 16. An adjusting nut 2 is sleeved on the upper part of the positioning rod 17, and the adjusting nut 2 is threadedly connected to the valve body 5. The adjusting nut 2 can be rotated to move it up and down, thereby adjusting the position of the adjusting nut 2, and the adjustment method is simple.

[0111] The outer sleeve of the positioning rod 17 is provided with a spring 4, and the positioning rod 17 is used to control the compression or extension direction of the spring 4 to prevent the spring 4 from being twisted and deformed, thereby affecting the elastic force of the spring 4. The lower end of the spring 4 abuts against the upper surface of the piston 16, and the upper end of the spring 4 abuts against the adjusting nut 2.

[0112] Furthermore, a guide groove is provided at the lower part of the adjusting nut 2, and the upper end of the spring 4 extends into the guide groove and abuts against the adjusting nut 2. The spring 4 is in a compressed state, and applies a pressure to the piston 16, which is a set pressure. When the pressure in the volume chamber is less than the set pressure, the piston 16 will fit on the step surface 27. When the pressure in the volume chamber is greater than the set pressure, the piston 16 will overcome the elastic force of the spring 4 and move upward, while driving the piston rod 10 to move upward. The adjusting nut 2 moves up and down by rotating, thereby adjusting the compression of the spring 4, adjusting the set pressure of the volume chamber, and controlling the brake cylinder pressure.

[0113] A rotating washer 3 is installed between the adjusting nut 2 and the spring 4, and the rotating washer 3 is used to prevent the spring 4 from rotating when the adjusting nut 2 rotates, thereby preventing the spring 4 from twisting.

[0114] A nut 1 is connected to the upper portion of the adjusting nut 2 , and the nut 1 is threadedly connected to the adjusting nut 2 . The nut 1 and the valve body 5 jointly fix the adjusting nut 2 to prevent the adjusting nut 2 from rotating and affecting the force of the spring 4 .

[0115] In order to discharge the volume chamber pressure to the atmosphere, a first side hole 21 is opened on the mounting seat 12 , and the first side hole 21 is connected to the volume chamber connecting hole 20 . Specifically, the first side hole 21 is arranged on the side wall of the secondary cavity 26 .

[0116] The plunger sleeve 14 is provided with a second side hole 22 in the radial direction. The second side hole 22 corresponds to the position of the first side hole 21 , and the first side hole 21 is communicated with the second side hole 22 .

[0117] The piston rod 10 is provided with a third side hole 23 in the radial direction, and when the piston 16 moves upward, the third side hole 23 is connected with the second side hole 22 and the first side hole 21. In this embodiment, when the piston 16 moves upward to the limit position, the third side hole 23 is connected with the second side hole 22 and the first side hole 21.

[0118] A vertical exhaust hole 24 is formed at the lower portion of the piston rod 10 . One end of the vertical exhaust hole 24 is connected to the third side hole 23 , and the other end is connected to the secondary cavity 26 . The vertical exhaust hole 24 is connected to the pressure relief hole 19 .

[0119] The lower outer side of the piston rod 10 is sleeved with a first sealing ring 11 and a second sealing ring 18, and the first sealing ring 11 and the second sealing ring 18 are respectively located on the upper side and the lower side of the third side hole 23. The first sealing ring 11 and the second sealing ring 18 are in sealing contact with the plunger sleeve 14. The first sealing ring 11 and the second sealing ring 18 play the role of sealing partition. When the piston rod 10 moves up and down, the first sealing ring 11 and the second sealing ring 18 are in sliding contact with the plunger sleeve 14. Due to the good wear resistance and sealing performance of the sealing ring, the wear is small after long-term use, and the sealing requirements can still be met, which solves the leakage problem of the metal grinding surface sealing structure after long-term use, ensures the sealing of the volume chamber pressure, prolongs the service life of the safety valve, and improves driving safety. Moreover, compared with the grinding process of the metal sealing surface, the use of the sealing ring reduces the production difficulty and improves the production efficiency. In addition, the sealing ring is easy to install and replace, and the operation is convenient.

[0120] A third sealing ring 8 is sleeved on the outer side of the piston 16 , and the third sealing ring 8 is in sealing contact with the mounting seat 12 .

[0121] A fourth sealing ring 9 is sleeved on the outer side of the upper portion of the piston rod 10 , and the fourth sealing ring 9 is in sealing contact with the piston 16 .

[0122] The third sealing ring 8 and the fourth sealing ring 9 play a sealing role to prevent the pressure in the volume chamber from leaking to the atmosphere through the piston rod 10 and the piston 16.

[0123] A fifth sealing ring 13 is installed between the mounting seat 12 and the volume chamber, and the fifth sealing ring 13 is used to prevent the pressure in the volume chamber from leaking to the atmosphere from the mounting position of the safety valve.

[0124] A fourth side hole is formed on the side wall of the mounting seat 12, and a screw plug 15 is installed in the fourth side hole. The screw plug 15 is a process plug and plays a sealing role.

[0125] Under the combined action of the volume chamber pressure and the spring force, the piston 16 drives the piston rod 10 and the first sealing ring 11 and the second sealing ring 18 installed thereon to move up and down according to the force difference between the upper and lower surfaces of the piston 16, thereby connecting or disconnecting the gas path between the volume chamber and the atmosphere, thereby realizing the pressure control function. When the volume chamber pressure is greater than the set pressure, the piston 16 drives the piston rod 10 to move upward, and the third side hole 23 on the piston rod 10 is connected with the second side hole 22 and the first side hole 21, and the volume chamber pressure enters the volume chamber connecting hole 20, and then passes through the first side hole 21, the second side hole 22, the third side hole 23, the vertical exhaust hole 24, and the pressure relief hole 19 in sequence, and is discharged to the atmosphere through the pressure relief hole 19. When the exhaust is completed, the piston 16 will move downward under the action of the spring 4, and the piston rod 10 will move downward accordingly. The third side hole 23 on the piston rod 10 is staggered with the second side hole 22, and the two are not connected. The upper and lower sides of the third side hole 23 are respectively closed by the first sealing ring 11 and the second sealing ring 18, so no air leakage will occur.

[0126] When the pressure in the volume chamber is less than the set pressure, the pressure in the volume chamber is insufficient to overcome the force applied by the spring 4 to the piston 16. At this time, the piston 16 and the piston rod 10 will not move upward.

[0127] By adjusting the compression amount of the spring 4, the force applied by the spring 4 to the piston 16 is adjusted to control the pressure in the volume chamber, thereby achieving the function of a safety valve and meeting the requirements for the use of safety valves in large-scale road maintenance machinery or locomotives.

[0128] Each sealing ring in this embodiment is an O-ring, and the material may be a rubber sealing ring.

[0129] The working principle of the present invention is:

[0130] Through the above structure, the pressure in the volume chamber is divided into two action directions. One is to be filled to the bottom of the piston 16, which is opposite to the action force of the spring 4, and the up and down movement of the piston 16 is controlled according to the force difference between the upper and lower surfaces of the piston 16; the other is to be filled to the piston rod 10 through the plunger sleeve 14, and when the volume chamber is communicated with the atmosphere, it is discharged to the atmosphere through the third side hole 23 on the piston rod 10, the vertical exhaust hole 24 and the pressure relief hole 19 on the mounting seat 12.

[0131] The safety valve mainly includes two working positions: open position and closed position:

[0132] (1) Open position

[0133] like Figure 4 and Figure 5 As shown, when the pressure in the volume chamber is greater than the sum of the spring force and the first sealing ring 11 and the resistance of the first sealing ring 11, the piston 16 drives the piston rod 10 to move upward, so that the first sealing ring 11 moves upward over the second side hole 22 on the plunger sleeve 14. At this time, the upper surface of the piston 16 contacts the valve body 5 and cannot move upward any further. The second side hole 22 on the plunger sleeve 14 communicates with the third side hole 23 on the piston rod 10, and the pressure in the volume chamber is discharged to the atmosphere through the plunger sleeve 14, the piston rod 10, and the mounting seat 12, and the pressure in the volume chamber decreases.

[0134] (2) Close position

[0135] like Figure 1-Figure 3 As shown, when the pressure in the volume chamber is less than the spring force, the spring force overcomes the first sealing ring 11 and the resistance of the first sealing ring 11, pushing the piston 16 and the piston rod 10 downward, so that the first sealing ring 11 moves downward over the second side hole 22 on the plunger sleeve 14. At this time, the lower surface of the piston 16 contacts the mounting seat 12 and cannot move downward any further. The air path between the second side hole 22 on the plunger sleeve 14 and the third side hole 23 on the piston rod 10 is blocked by the first sealing ring 11, and the pressure in the volume chamber stops being discharged and remains unchanged.

[0136] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A plunger type safety valve for railway air brake system, characterized in that: It comprises a valve body and a mounting seat, wherein the valve body is connected to the mounting seat, the mounting seat is connected to a volume chamber, and the pressure of the volume chamber can enter the mounting seat; the mounting seat is also connected to the atmosphere; A safety valve opening component is arranged in the mounting seat, and a pre-pressure component is arranged in the valve body, and the pre-pressure component is used to apply pre-pressure, the pre-pressure acts on one side of the safety valve opening component, and the volume chamber pressure acts on the other side of the safety valve opening component; The safety valve opening component can move under the combined action of the pre-pressure and the volume chamber pressure, thereby connecting or disconnecting the gas path between the volume chamber and the atmosphere; A sealing ring is arranged on the sealing surface of the safety valve opening component.

2. The plunger type safety valve for railway air brake system according to claim 1, characterized in that: The mounting seat is provided with a concave cavity, the safety valve opening component is located in the concave cavity, and the safety valve opening component can move up and down in the concave cavity.

3. The plunger type safety valve for railway air brake system according to claim 2, characterized in that: A primary cavity is arranged on the upper part of the mounting seat, a secondary cavity is arranged at the bottom of the primary cavity, the primary cavity is communicated with the secondary cavity, and a plunger sleeve is installed in the secondary cavity; The safety valve opening component includes a piston rod and a piston, and the piston is connected to one end of the piston rod; the piston rod is located in the plunger sleeve, and the piston is located in the primary concave cavity. The piston rod is slidably connected to the plunger sleeve, and the sealing ring is sleeved on the piston rod, and the sealing ring is slidably connected to the plunger sleeve.

4. The plunger type safety valve for railway air brake system according to claim 3, characterized in that: The pre-pressing component is an elastic telescopic component, and the telescopic direction of the elastic telescopic component is perpendicular to the upper surface of the piston.

5. The plunger type safety valve for railway air brake system according to claim 4, characterized in that: One end of the elastic telescopic component abuts against the piston, and the other end of the elastic telescopic component abuts against the pressure regulating component, and the pressure regulating component is connected to the valve body.

6. The plunger type safety valve for railway air brake system according to claim 5, characterized in that: A positioning component is connected to the upper portion of the pressure regulating component, and the positioning component is used to position the pressure regulating component after it is adjusted to a target position.

7. The plunger type safety valve for railway air brake system according to claim 3, characterized in that: A volume chamber communicating hole is provided on the mounting seat, one end of the volume chamber communicating hole is communicated with the volume chamber, the other end of the volume chamber communicating hole is communicated with the primary concave cavity, and the volume chamber communicating hole is arranged opposite to the lower surface of the piston.

8. The plunger type safety valve for railway air brake system according to claim 7, characterized in that: The mounting seat is provided with a first side hole, the first side hole being connected to the volume chamber communication hole; A second side hole is opened in the radial direction of the plunger sleeve, the second side hole corresponds to the position of the first side hole, and the first side hole is connected to the second side hole; The piston rod is provided with an exhaust hole, and when the piston moves upward, the exhaust hole is connected with the second side hole and the first side hole; A pressure relief hole is provided on the mounting seat, the pressure relief hole is connected to the atmosphere, and the exhaust hole is connected to the pressure relief hole.

9. The plunger type safety valve for railway air brake system according to claim 8, characterized in that: The exhaust hole includes a third side hole opened in the radial direction of the piston rod and a vertical exhaust hole opened in the lower part of the piston rod, one end of the vertical exhaust hole is connected to the third side hole, the other end of the vertical exhaust hole is connected to the secondary concave cavity, and the vertical exhaust hole is connected to the pressure relief hole.

10. The plunger type safety valve for railway air brake system according to claim 9, characterized in that: The lower outer side of the piston rod is sleeved with a first sealing ring and a second sealing ring, the first sealing ring and the second sealing ring are respectively located on the upper side and the lower side of the third side hole, and the first sealing ring and the second sealing ring are in sealing contact with the plunger sleeve.

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