CN110848434B

CN110848434B - Safety valve

Info

Publication number: CN110848434B
Application number: CN201911121742.9A
Authority: CN
Inventors: 黄延军; 邵玉刚
Original assignee: Zhejiang Wandekai Fluid Equipment Technology Co ltd
Current assignee: ZHEJIANG WANDEKAI FLUID EQUIPMENT TECHNOLOGY Co.,Ltd.
Priority date: 2019-11-15
Filing date: 2019-11-15
Publication date: 2021-07-23
Anticipated expiration: 2039-11-15
Also published as: CN110848434A

Abstract

The invention belongs to the technical field of industrial valves. The invention discloses a safety valve, which comprises a main valve body, a main valve core, a connecting plate and a pilot valve, wherein the main valve body is provided with a main valve core; one end of the main valve core is connected with the connecting plate, the other end of the main valve core is in flat contact with the plane where the main channel is located, the pilot valve controls the flow of working oil which flows to the connecting plate and drives the main valve core to rotate, so that the rotation direction of the main valve core relative to the connecting plate is controlled, the on-off control of the main valve core on the main channel is controlled, and the opening and closing control of the main channel between the oil inlet and the oil outlet along the horizontal direction is achieved. The safety valve of the invention can not only avoid the jamming of the main valve core caused by concentricity and ensure the smooth operation of overflow action, but also improve the protection of the sealing surface and reduce the start-stop impact, and improve the service life and the working stability of the whole safety valve.

Description

Safety valve

Technical Field

The invention belongs to the technical field of industrial valves, and particularly relates to a safety valve.

Background

A pilot operated safety valve is an optimal overpressure protection device on pressurized equipment, containers or pipelines and is mainly used in the fields of petroleum, chemical industry, electric power, metallurgy and the like. However, during the process of manufacturing and assembling the safety valve, the subsequent practical use performance of the safety valve is affected for various reasons.

At present, in a conventional pilot operated safety valve, the opening and closing of the safety valve are realized through the relative axial movement between a main valve core and a main valve seat which are positioned on the same axis. However, during the machining and assembling process, due to the accumulation of errors, the concentricity of the main valve core and the main valve seat may be deviated, the main valve may not be flexible, and the safety valve may not be opened smoothly under the rated pressure. In addition, main valve core when opening, can adhere to on the sealed face of main valve core and have impurity, and the existence of impurity can lead to main valve core's leakproofness not good when closing to cause the damage to main valve core and the sealed face of main valve seat, main valve core can take place to strike the collision with the sealed face of main valve seat when opening and close moreover, leads to main valve core and main valve seat's sealed face to further receive the damage and influence life. In addition, when the conventional pilot operated safety valve works, the opening and closing actions of the main valve are usually rapid, so that great pressure impact is generated, and the pressure impact can bring great burden to the system, cause the loss of the system and influence the service life of the system.

Disclosure of Invention

In order to solve the problems of the prior pilot operated safety valve, the invention provides a safety valve with a brand new structure. The safety valve comprises a main valve body, a main valve core, a connecting plate and a pilot valve; the pilot valve is inserted and fixed on the main valve body, an oil inlet, an oil outlet, a first oil hole, a second oil hole, a third oil hole and a fourth oil hole are formed in the main valve body, and the oil inlet is communicated with the oil outlet through a main channel;

the pilot valve is provided with a pilot oil port, a first control oil port, a second control oil port, an oil return port and a pilot valve core; the pilot valve core is used for keeping the second control oil port and the oil return port communicated when the pilot oil port is controlled to be communicated with the first control oil port, and keeping the first control oil port and the oil return port communicated when the pilot oil port is controlled to be communicated with the second control oil port;

the connecting plate is positioned in the valve body, the upper end face of the connecting plate is provided with an installation groove, and an arc-shaped groove is formed in the installation groove;

the two ends of the main valve core are respectively a driving end and a control end which are arranged along the horizontal direction, and the driving end is provided with a sliding block; the driving end is positioned in the mounting groove and can rotate in the mounting groove so as to drive the control end to rotate, the sliding block is positioned in the arc-shaped groove and can slide back and forth along the arc-shaped groove, and sliding seal is formed between the sliding block and the arc-shaped groove; the control end keeps flat contact with the plane where the main channel is located, a through hole penetrating through the wall thickness of the main channel in the axial direction is formed in the control end, and the main channel is located on the circumference of the through hole rotating along with the control end;

the first oil hole is communicated with the oil inlet and the pilot oil port, the second oil hole is communicated with the first control oil port and one end of the arc-shaped groove, and the third oil hole is communicated with the second control oil port and the other end of the arc-shaped groove; the fourth oil hole is communicated with the oil return port and the oil outlet.

Preferably, the pilot valve spool comprises a pilot control rod and a rotary valve spool; the pilot control rod penetrates through the rotary valve core along the axial direction, and when the pilot control rod moves axially, the rotary valve core rotates around the pilot control rod in the circumferential direction; the outer surface of the rotary valve core is provided with a first groove and a second groove which are respectively formed along the axial direction, the first groove and the second groove are distributed in a staggered mode along the circumferential direction, meanwhile, the first control oil port and the second control oil port are distributed in a staggered mode along the circumferential direction, and the staggered relation of the first groove and the second groove corresponds to the staggered relation of the first control oil port and the second control oil port; the first groove is used for communicating the pilot oil port with the first control oil port or the second control oil port, and the second groove is used for communicating the oil return port with the second control oil port or the first control oil port.

Further preferably, an inner rotary groove is formed in one end of the rotary valve core, a boss is arranged on the pilot control rod, the boss is located in the inner rotary groove and can slide back and forth along the inner rotary groove, and relative movement in the axial direction and relative rotation in the circumferential direction between the rotary valve core and the pilot control rod are formed.

Further preferably, the pilot valve further comprises a pilot valve body and a pilot spring; the pilot valve body is connected with the main valve body, and the pilot spring is positioned in the pilot valve body; the pilot control rod penetrates through the rotary valve core along the axial direction, one end of the pilot control rod is positioned in the pilot oil port area, and the other end of the pilot control rod extends into the pilot valve body and is contacted with the pilot spring; and a guide flat key along the axial direction is arranged between the pilot control rod and the pilot valve body.

Further preferably, the pilot valve further comprises a pilot valve sleeve; the pilot valve sleeve is connected with the pilot valve body and sleeved on the rotary valve core, and the pilot oil port, the first control oil port, the second control oil port and the oil return port are located on the pilot valve sleeve.

Further preferably, the pilot valve body is provided with an adjusting screw; the adjusting screw is in threaded connection with the pilot valve body, and one end of the adjusting screw extends into the pilot valve body and is in contact with the pilot spring.

Preferably, the main valve core is of a split structure, and the control end is fixedly connected with the driving end in a detachable mode.

Further preferably, the control end and the driving end are connected in a plug-in manner, and are fixed in the circumferential direction through a positioning flat key.

Further preferably, the safety valve is also provided with a compression spring; the compression spring is sleeved on the main valve core, one end of the compression spring is in contact with the control end, the other end of the compression spring is in contact with the connecting plate, pressing force is generated on the control end, and the control end is kept in flat contact with a plane where the main channel is located.

Preferably, the main valve body is of a split structure and comprises a first valve body provided with an oil inlet and an oil outlet and a second valve body used for installing the pilot valve, and the connecting plate is fixed between the first valve body and the second valve body.

Compared with the prior safety valve, when the safety valve disclosed by the invention is used for overflowing working medium in a system, the safety valve has the following beneficial technical effects:

1. according to the invention, through the connection between the main valve core and the connecting plate and the drive control of the reciprocating rotation of the main valve core by introducing working medium into the connecting plate, the main channel between the oil inlet and the oil outlet is gradually covered, closed and opened along the horizontal direction in the reciprocating rotation process of the main valve core, so that the purpose of controlling the on-off of an oil path between the oil inlet and the oil outlet is achieved. Therefore, the opening and closing control mode between the oil inlet and the oil outlet is formed by the axial relative movement between the main valve core and the main valve seat in the conventional safety valve, so that the problem that the action of the main valve is blocked due to the deviation of the concentricity of the main valve core and the main valve seat caused by machining or assembly errors can be avoided, the smooth opening and closing of the safety valve can be ensured, the impact collision generated when the main valve core and the main valve seat are opened and closed along the axial direction can be avoided, the protection of the main valve core is realized, and the service life of the whole safety valve is prolonged.

2. In the safety valve, the main valve core can gradually control the opening of the main channel in the horizontal rotation process until the main valve core is completely opened or closed. Therefore, pressure impact on the system when the conventional safety valve is opened rapidly is avoided, and the stability of the system is improved. In addition, through the back and forth rotation of the main valve core in the horizontal direction, impurities attached to the sealing surfaces when the main channel is opened can be scraped off in the reverse rotation process of closing, so that the problem that the sealing surfaces are damaged due to the fact that the impurities are pressed between the sealing surfaces when the main channel is closed is solved, the sealing effect of the main valve core on the main channel is guaranteed, and the working reliability of the whole safety valve is improved.

3. In the invention, the main valve core is improved to rotate in a reciprocating way along the horizontal direction to complete the opening and closing control of the main valve, so that the axial size requirement on the valve body can be greatly reduced, the axial size of the whole safety valve is reduced, and the structure compactness of the whole safety valve is improved.

4. In the invention, the pilot valve core in the pilot valve is designed to be in a form consisting of the pilot control rod and the rotary valve core, and the first grooves and the second grooves which are staggered along the circumferential direction are distributed on the outer surface of the rotary valve core, so that when the pilot control rod moves axially, the rotary valve core can be driven to rotate around the pilot control rod in the circumferential direction, and the communication relation among the pilot oil port, the first control oil port, the second control oil port and the oil return port is controlled by the first grooves and the second grooves. Like this, through rotatory case around the pilot control pole rotation realize the break-make switching between the different oil circuits, when having not only avoided conventional pilot valve to carry out the oil circuit break-make switching, the impact collision between case and the disk seat to the realization is to the protection of spare part in the pilot valve, has improved the life and the performance of pilot valve, and the axial dimensions who has significantly reduced the pilot valve moreover requires, thereby improves the compact structure nature of pilot valve.

Drawings

FIG. 1 is a schematic view of the safety valve of the present embodiment;

FIG. 2 is a schematic cross-sectional view of the safety valve in the closed state of the present embodiment;

FIG. 3 is a schematic partial sectional view of the pilot valve and the main valve body of FIG. 2;

FIG. 4 is a schematic cross-sectional view taken along the line W-W in FIG. 3;

FIG. 5 is a schematic cross-sectional view taken at H-H in FIG. 2;

FIG. 6 is a sectional view of the safety valve in the open state in the present embodiment;

FIG. 7 is a schematic partial sectional view of the pilot valve and the main valve body of FIG. 6;

FIG. 8 is a schematic cross-sectional view taken along the direction N-N in FIG. 7;

FIG. 9 is a schematic cross-sectional view taken at F-F of FIG. 6;

FIG. 10 is a schematic structural diagram of the rotary valve core in the present embodiment;

FIG. 11 is a schematic structural diagram of the pilot control lever of the present embodiment;

FIG. 12 is a schematic structural diagram of a control end of a main valve element of the present embodiment;

fig. 13 is a schematic structural diagram of the external shape of the driving end in the main valve core of the present embodiment.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and embodiments.

Referring to fig. 1 to 5, the safety valve of the present embodiment includes a main valve body 1, a main valve element 2, a connecting plate 3, and a pilot valve 4. The pilot valve 4 is inserted and fixed on the main valve body 1 along the horizontal direction, an oil inlet 11, an oil outlet 12, a first oil hole 13, a second oil hole 14, a third oil hole 15 and a fourth oil hole 16 are arranged on the main valve body 1, and the oil inlet 11 is communicated with the oil outlet 12 through a main channel 17 which is opened along the vertical direction.

The connecting plate 3 is located the inside of valve body 1 to the up end of connecting plate 3 is equipped with the mounting groove, is equipped with arc wall 32 in the bottom of mounting groove.

Two ends of the main valve core 2 are respectively a driving end 21 and a control end 22 arranged along the horizontal direction, the driving end 21 and the control end 22 are fixedly connected, and a slider 23 is arranged on the driving end 21. Wherein, drive end 21 is located the mounting groove to can rotate in the mounting groove, and then drive control end 22 and rotate. The sliding block 23 is positioned in the arc-shaped groove 32 and can slide back and forth in the arc-shaped groove 32, and sliding seal is formed between the sliding block 23 and the arc-shaped groove 32. At the moment, the slide block is divided into two relatively independent parts in the process of sliding in the arc-shaped groove, and then two independent sealing cavities are formed with the driving end. The control end 22 is in flat contact with the plane of the main channel 17 and is provided with a through hole 221 axially penetrating the wall thickness thereof, and the main channel 17 is located on the circumference of the through hole 221 rotating with the control end 22. At the moment, the through hole and the main channel are switched between aligned communication and staggered sealing along with the horizontal rotation of the control end, so that on-off control of the oil inlet and the oil outlet through the main channel is formed.

The pilot valve 4 is provided with a pilot oil port 41, a first control oil port 42, a second control oil port 43, an oil return port 44, and a pilot valve core 45. The pilot valve core 45 is configured to maintain a communication relationship between the second control oil port 43 and the oil return port 44 when controlling the communication between the pilot oil port 41 and the first control oil port 42, and maintain a communication relationship between the first control oil port 42 and the oil return port 44 when controlling the communication between the pilot oil port 41 and the second control oil port 43.

In addition, the first oil hole 13 communicates the oil inlet 11 and the pilot oil hole 41, the second oil hole 14 communicates the first control oil hole 42 and one end of the arc-shaped groove 32, the third oil hole 15 communicates the second control oil hole 43 and the other end of the arc-shaped groove 32, and the fourth oil hole 16 communicates the oil return hole 44 and the oil outlet 12.

As shown in fig. 3 and 4, in the present embodiment, the pilot valve spool 45 includes a pilot control rod 451 and a rotary valve spool 452. The pilot lever 451 extends through the rotary valve body 452 in the axial direction, and when the pilot lever 451 moves in the axial direction, the rotary valve body 452 simultaneously rotates in the circumferential direction around the pilot lever 451.

Referring to fig. 3 to 10, a first groove 4521 and a second groove 4522, which are respectively opened along an axial direction, are formed in an outer surface of the rotary valve core 452, the first groove 4521 and the second groove 4522 are alternately arranged along a circumferential direction of the rotary valve core 452, meanwhile, the first control oil ports 42 and the second control oil ports 43 are alternately arranged along the circumferential direction, and an alternate relationship between the first groove 4521 and the second groove 4522 corresponds to an alternate relationship between the first control oil ports 42 and the second control oil ports 43. At this time, the first groove 4521 is used for communication between the pilot port 41 and the first control port 42 or the second control port 43, and the second groove 4522 is used for communication between the return port 44 and the second control port 43 or the first control port 42.

Thus, when the rotary valve core 452 rotates around the pilot control rod 451 until the first groove 4521 communicates the pilot oil port 41 with the first control oil port 42, the second groove 4522 communicates the oil return port 44 with the second control oil port 43; conversely, when the rotary spool 452 rotates around the pilot control rod 451 until the first groove 4521 communicates the pilot oil port 41 with the second control oil port 43, the second groove 4522 communicates the oil return port 44 with the first control oil port 42. At the moment, the closed cavities on two sides of the sliding block 23 in the arc-shaped groove are respectively communicated with the oil inlet 11 and the oil outlet 12 in an alternating mode, so that the sliding block 23 slides in the arc-shaped groove 32 in a reciprocating mode under the action of oil hydraulic pressure on two sides, and the sliding block 23 drives the driving end 21 to rotate in a reciprocating mode in the circumferential direction in the installation groove. Similarly, in other embodiments, other structures of the pilot valve can be adopted, and the control oil inlet and the control oil outlet are alternately communicated with the closed cavities at two sides of the sliding block in the arc-shaped groove, for example, a structure of a reversing slide valve which moves back and forth along the axial direction is adopted.

Preferably, as shown in fig. 3 and 4, and fig. 10 and 11, in the present embodiment, an inner rotary groove 4523 is provided at one end of the rotary valve body 452, and a boss 4511 is provided on the pilot lever 451. When the pilot lever 451 passes through the rotary spool 452, the boss 4511 is located in the inner rotary groove 4523 and is slidable back and forth along the inner rotary groove 4523, so that relative rotation in the circumferential direction is simultaneously performed while the rotary spool 452 and the pilot lever 451 are axially moved relative to each other.

Further, as shown in fig. 3 and 4, the pilot valve 4 further includes a pilot valve body 46 and a pilot spring 47. The pilot valve body 46 is screwed to the main valve body 1, and a pilot spring 47 is provided in the pilot valve body 46. After the pilot control rod 451 axially penetrates through the rotary valve core 452, one end thereof is located in a region where the pilot oil port 41 communicates with the first oil hole 14, and the other end thereof extends into the pilot valve body 46 to contact the pilot spring 47 through a spring seat, so that the pilot control rod axially reciprocates under the combined action of the working medium and the spring.

Meanwhile, as shown in fig. 3 and 11, a guide flat key 48 is provided in the axial direction in a region where the pilot control lever 451 contacts the pilot valve body 46. The pilot flat key 48 is installed and guided by providing the pilot control rod 451 and the pilot valve body 46 with corresponding axial keyways 4512. In this way, when the pilot control rod moves axially, under the axial guiding action of the guiding flat key, only the linear movement in the axial direction can be carried out, so that the rotary valve core rotates in the circumferential direction.

As shown in fig. 3 and 4, in the pilot valve 4 of the present embodiment, a pilot valve sleeve 49 is further provided. The pilot valve sleeve 49 is connected with the pilot valve body 46 through a thread and sleeved on the rotary valve core 452, and the pilot oil port 41, the first control oil port 42, the second control oil port 43 and the oil return port 44 are all arranged on the pilot valve sleeve 49. Like this, can improve the accurate processing to four position relations of pilot oil mouth, first control hydraulic fluid port, second control hydraulic fluid port and oil return opening, when guaranteeing that rotatory case rotates in the pilot valve cover, to the accurate control of the relation of intercommunication between pilot oil mouth, first control hydraulic fluid port, second control hydraulic fluid port and the oil return opening four, improve the action precision of whole pilot valve.

In addition, as shown in fig. 3 and 4, an adjusting screw 410 is provided on the pilot valve body 46. The adjustment screw 410 is threadedly coupled to the pilot valve body 46 through a valve seat and extends into the pilot valve body 46 at one end into contact with the pilot spring 47. Thus, by adjusting the adjusting screw, the pressing force of the pilot spring can be adjusted, thereby controlling the action of the pilot valve core.

Referring to fig. 2, 12 and 13, in this embodiment, main valve element 2 is a split structure, that is, driving end 21 and control end 22 are fixedly and detachably connected, so as to facilitate the processing and dismounting operations of the main valve element. Furthermore, the driving end 21 and the control end 22 are connected in an inserting manner, and are fixed in the circumferential direction through the positioning flat keys 24, so that the driving end 21 and the control end 22 can rotate synchronously in the circumferential direction.

Referring to fig. 2, the safety valve of the present embodiment further includes a compression spring 5. The compression spring 5 is sleeved on the main valve element 2 along the vertical direction, the lower end of the compression spring is in contact with the control end 22, and the upper end of the compression spring is in contact with the connecting plate 3. At this time, the pressing spring 5 can generate a downward pressing force on the control end 22, so that the control end 22 is kept in flat contact with the plane of the main channel 17, and the sealing effect of the control end 22 on the main channel 17 is further ensured.

In addition, as shown in fig. 1 and fig. 2, in the present embodiment, the main valve body 1 is of a split structure, and includes a first valve body 1a provided with an oil inlet and an oil outlet, and a second valve body 1b for mounting the pilot valve 4, and the first valve body 1a and the second valve body 1b are connected by a bolt, and at the same time, the connecting plate 3 is fixed between the first valve body 1a and the second valve body 1 b. Therefore, the machining of each oil port and each oil hole in the main valve body is facilitated, the follow-up quick assembly of the main valve core is facilitated, and the machining and assembling efficiency of the whole safety valve is improved.

Referring to fig. 2 to 13, when the safety valve of the present embodiment is used, a working medium in the system enters the safety valve from the oil inlet, and the specific working principle is as follows:

when the system pressure is lower than the opening pressure of the pilot valve 4, that is, the working medium is lower than the corresponding pressure set by the pilot spring 47, after the working medium flows to the pilot oil port 41 of the pilot valve 4 through the oil inlet 11 and the first oil hole 13, the pilot control rod 451 is kept in a normal state under the action of the pilot spring 47, that is, in the position shown in fig. 3 and 4, the first groove 4521 communicates the pilot oil port 41 with the first control oil port 42, and the second groove 4522 communicates the oil return port 44 with the second control oil port 43. Thus, the working medium at the oil inlet 11 flows from the pilot oil port 41 to the arc-shaped groove 32 after sequentially passing through the first groove 4521, the first control oil port 42 and the second oil hole 14, and generates an upward force on the slider 23 as shown in fig. 5, and at the same time, the working medium in the arc-shaped groove 32 in the upper region of the slider 23 as shown in fig. 5 flows to the oil outlet 12 after sequentially passing through the third oil hole 15, the second control oil port 43, the second groove 4522, the oil return port 44 and the fourth oil hole 16. At this time, the working medium acting force on the lower side of the slider 23 is greater than the working medium acting force on the upper side of the slider, so that the slider is kept at the uppermost position of the arc-shaped groove 23 shown in fig. 5, and the through hole 221 on the valve core 2 and the main channel 17 are in a missing position relationship to keep the main channel 17 blocked, so that the safety valve is kept in a normally closed state.

When the system pressure is higher than the opening pressure of the pilot valve 4, that is, the working medium is higher than the corresponding pressure set by the pilot spring 47, the working medium flows to the pilot oil port 41 of the pilot valve 4 through the oil inlet 11 and the first oil hole 13, and then generates an acting force against the pilot spring 47 on the pilot control rod 451, so as to push the pilot control rod 451 to move axially, and further drive the rotary valve core 452 to rotate, so that the first groove 4521 communicates the pilot oil port 41 with the second control oil port 43, and the second groove 4522 communicates the oil return port 44 with the first control oil port 42. Thus, the working medium at the oil inlet 11 flows from the pilot oil port 41 to the arc-shaped groove 32 after sequentially passing through the first groove 4521, the second control oil port 43 and the third oil hole 15, and generates a downward force on the slider 23 as shown in fig. 9, and at the same time, the working medium in the arc-shaped groove 32 in the area below the slider 23 as shown in fig. 9 flows to the oil outlet 12 after sequentially passing through the second oil hole 14, the first control oil port 42, the second groove 4522, the oil return port 44 and the fourth oil hole 16. At this time, the acting force of the working medium on the upper side of the slider 23 is greater than the acting force of the working medium on the lower side of the slider, so that the slider slides downwards to the position shown in fig. 9 along the arc-shaped groove 23, and then the driving end 21 drives the control end 22 to rotate in the horizontal direction, so that the through hole 221 gradually rotates to the position relation completely aligned with the main channel 17 in the horizontal direction, the oil inlet 11 and the oil outlet 12 are communicated through the main channel 17, the safety valve enters an open state, and the overflow operation of the safety valve on the working medium in the system is realized.

When the system medium pressure is reduced, the pilot control rod 451 moves in the opposite direction and returns under the action of the pilot spring 47, so that the first groove 4521 communicates the pilot oil port 41 with the first control oil port 42 again, and the second groove 4522 communicates the oil return port 44 with the second control oil port 43 again. Thus, the slide block 23 slides along the arc-shaped groove 32 to the position shown in fig. 5 again under the action of the force difference of the working medium on the two sides, so as to drive the driving end 21 and the control end 22 to rotate in opposite directions, so that the through hole 221 and the main channel 17 are staggered again, and further the main channel 17 is blocked, so that the safety valve enters a normally closed state again, and the overflow operation of the safety valve on the working medium in the system is stopped.

Claims

1. A safety valve is characterized by comprising a main valve body, a main valve core, a connecting plate and a pilot valve; the pilot valve is inserted and fixed on the main valve body, an oil inlet, an oil outlet, a first oil hole, a second oil hole, a third oil hole and a fourth oil hole are formed in the main valve body, and the oil inlet is communicated with the oil outlet through a main channel;

the first oil hole is communicated with the oil inlet and the pilot oil port, the second oil hole is communicated with the first control oil port and one end of the arc-shaped groove, and the third oil hole is communicated with the second control oil port and the other end of the arc-shaped groove; the fourth oil hole is communicated with the oil return port and the oil outlet;

the pilot valve core comprises a pilot control rod and a rotary valve core; the pilot control rod penetrates through the rotary valve core along the axial direction, and when the pilot control rod moves axially, the rotary valve core rotates around the pilot control rod in the circumferential direction; the outer surface of the rotary valve core is provided with a first groove and a second groove which are respectively formed along the axial direction, the first groove and the second groove are distributed in a staggered mode along the circumferential direction, meanwhile, the first control oil port and the second control oil port are distributed in a staggered mode along the circumferential direction, and the staggered relation of the first groove and the second groove corresponds to the staggered relation of the first control oil port and the second control oil port; the first groove is used for communicating the pilot oil port with the first control oil port or the second control oil port, and the second groove is used for communicating the oil return port with the second control oil port or the first control oil port; one end of the rotary valve core is provided with an inner rotary groove, the pilot control rod is provided with a boss, and the boss is positioned in the inner rotary groove and can slide back and forth along the inner rotary groove to form relative movement between the rotary valve core and the pilot control rod along the axial direction and relative rotation along the circumferential direction.

2. The safety valve of claim 1, further comprising a pilot valve body and a pilot spring; the pilot valve body is connected with the main valve body, and the pilot spring is positioned in the pilot valve body; the pilot control rod penetrates through the rotary valve core along the axial direction, one end of the pilot control rod is positioned in the pilot oil port area, and the other end of the pilot control rod extends into the pilot valve body and is contacted with the pilot spring; and a guide flat key along the axial direction is arranged between the pilot control rod and the pilot valve body.

3. The safety valve of claim 2, further comprising a pilot valve sleeve; the pilot valve sleeve is connected with the pilot valve body and sleeved on the rotary valve core, and the pilot oil port, the first control oil port, the second control oil port and the oil return port are located on the pilot valve sleeve.

4. The safety valve according to claim 2, characterized in that the pilot valve body is provided with an adjusting screw; the adjusting screw is in threaded connection with the pilot valve body, and one end of the adjusting screw extends into the pilot valve body and is in contact with the pilot spring.

5. The safety valve according to any one of claims 1 to 4, wherein the main spool is of a split type structure, and the control end is fixedly connected with the driving end in a detachable manner.

6. The safety valve of claim 5, wherein the control end is in plug-in connection with the driving end and is secured circumferentially by a flat key.

7. The safety valve of claim 5, further provided with a hold-down spring; the compression spring is sleeved on the main valve core, one end of the compression spring is in contact with the control end, the other end of the compression spring is in contact with the connecting plate, pressing force is generated on the control end, and the control end is in flat contact with the plane where the main channel is located.

8. The safety valve according to any one of claims 1 to 4, wherein said main valve body is of a split type structure including a first valve body provided with an oil inlet and an oil outlet, and a second valve body for mounting said pilot valve, said connecting plate being fixed between said first valve body and said second valve body.