CN112983804A

CN112983804A - Plunger piston

Info

Publication number: CN112983804A
Application number: CN201911292979.3A
Authority: CN
Inventors: 刘书豪; 陈俊宏; 刘树飞; 苏诗策; 唐勇
Original assignee: Chengdu Bison Technology Co ltd
Current assignee: Chengdu Bison Technology Co ltd
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2021-06-18
Anticipated expiration: 2039-12-13
Also published as: CN112983804B

Abstract

The application relates to the technical field of natural gas and oil exploitation, and discloses a plunger, including core, seal gasket, first elasticity reset, outer current-limiting pipe and interior current-limiting post. The core body is internally provided with a fluid channel extending along the axial direction of the core body, the outer flow limiting pipe is arranged in the fluid channel, the inner peripheral surface of the outer flow limiting pipe is provided with a plurality of outer flow limiting rings protruding inwards in the radial direction, the outer flow limiting rings are arranged at intervals along the axial direction, the inner flow limiting column is arranged in the outer flow limiting pipe, the outer peripheral surface of the inner flow limiting column is provided with a plurality of inner flow limiting rings protruding outwards in the radial direction, and the inner flow limiting rings are arranged at intervals along the axial direction; the inner restrictor rings and the outer restrictor rings are alternately arranged along the axial direction; the outer diameter of the inner flow limiting ring is larger than the inner diameter of the outer flow limiting ring; the outer diameter of the inner flow limiting ring is smaller than the inner diameter of the outer flow limiting pipe; the distance between the adjacent outer flow restricting rings is larger than the thickness of the inner flow restricting ring. The application provides a plunger can be descended smoothly under the shut-in state, can ensure simultaneously and lift efficiency.

Description

Plunger piston

Technical Field

The application relates to the technical field of natural gas and oil exploitation, in particular to a plunger.

Background

In the development of gas or oil wells, it is necessary to lift the liquid charge at the bottom of the well to the surface in order to increase the production of gas or oil.

A plunger is provided in the related art. The periphery of the core body of the plunger is provided with a plurality of sealing gaskets, and the sealing gaskets are contacted with the inner wall of the well under the action of the elastic piece to form sealing. In the shut-in state, the plunger descends to the bottom of the well. When the well is opened, the pressure generated by the fluid below the plunger drives the plunger to move upwards, so that the accumulated liquid above the plunger is lifted upwards, and the accumulated liquid above the plunger is discharged through a well mouth.

The problem with the above-mentioned plunger is that under the combined action of fluid resistance and the frictional force of seal gasket and well inner wall, the plunger may not descend when shut in.

Some attempts have been made to solve the above problem by providing a flow passage in the plunger which extends vertically therethrough. The plunger can be more easily descended by arranging the vertically through flow channel, but the leakage of the plunger in ascending is greatly increased, so that the lifting efficiency is greatly reduced.

Disclosure of Invention

Embodiments of the present application provide a plunger that can smoothly descend in a shut-in state while ensuring lifting efficiency.

In order to achieve the above purpose, the embodiments of the present application adopt the following technical solutions:

a plunger, comprising: the fluid channel extends along the axial direction of the columnar core body, and an upper fluid hole and a lower fluid hole which are communicated with the fluid channel and the outside are respectively formed at the two axial ends of the core body; a plurality of sealing gaskets arranged around the core and configured to reciprocate in a radial direction; a first elastic restoring member acting on the sealing gasket and configured to exert a radially outward elastic force on the sealing gasket; the outer flow limiting pipe is arranged in the fluid channel, the inner circumferential surface of the outer flow limiting pipe is provided with a plurality of outer flow limiting rings which radially and inwards protrude, and the outer flow limiting rings are axially arranged at intervals; the outer peripheral surface of the inner flow limiting column is provided with a plurality of inner flow limiting rings which radially protrude outwards, and the inner flow limiting rings are arranged at intervals along the axial direction; wherein, the inner restrictor ring and the outer restrictor ring are alternately arranged along the axial direction; the outer diameter of the inner flow limiting ring is larger than the inner diameter of the outer flow limiting ring; the outer diameter of the inner flow limiting ring is smaller than the inner diameter of the outer flow limiting pipe; the distance between the adjacent outer flow restricting rings is larger than the thickness of the inner flow restricting ring.

Furthermore, the inner flow limiting column and the outer flow limiting pipe are both fixedly arranged; and a gap exists between the inner flow limiting ring and the outer flow limiting ring along the axial direction.

Furthermore, one of the inner flow limiting column and the outer flow limiting pipe is fixedly arranged, and the other one of the inner flow limiting column and the outer flow limiting pipe is axially movably arranged.

Furthermore, the plunger piston also comprises a guide post extending along the axial direction, one end of the core body is provided with a guide hole extending along the axial direction, and the guide post is matched with the guide hole in a sliding way; the guide post is connected with one of the inner flow limiting post and the outer flow limiting pipe which can move axially.

Further, one of the inner flow limiting column and the outer flow limiting pipe is fixedly arranged, and the other one of the inner flow limiting column and the outer flow limiting pipe can be axially adjusted in position.

Furthermore, the plunger piston also comprises a screw rod extending along the axial direction, and one end of the core body is provided with an internal thread through hole extending along the axial direction; the screw rod is in threaded fit with the internal threaded hole; the screw is connected with one of the inner flow-limiting column and the outer flow-limiting pipe, which can be adjusted axially.

Further, the screw extends to the outside of the core.

Furthermore, the plunger piston also comprises a locking nut, and the locking nut is in threaded connection with the part of the screw rod, which is positioned outside the core body.

Further, the outer circumferential surface of the outer restrictor tube is in contact with the inner circumferential surface of the fluid passage.

Further, in the radial direction, the outer flow limiting pipe comprises two parts which are independent and symmetrical with each other.

Furthermore, a plurality of outer restrictor rings are arranged at equal intervals along the axial direction, and a plurality of inner restrictor rings are arranged at equal intervals along the axial direction; the distance between the adjacent outer flow restricting rings is equal to the distance between the adjacent inner flow restricting rings.

The technical scheme of the application has following advantage and beneficial effect at least:

in the plunger that the embodiment of this application provided, can make interior current-limiting post and outer current-limiting pipe all fixed settings, also can make one of interior current-limiting post and outer current-limiting pipe fixed settings and the setting that another can the axial activity, but also can make the setting of interior current-limiting post axial adjustment position in outer current-limiting pipe.

The inner flow-limiting column and the outer flow-limiting pipe are both fixedly arranged, and a gap exists between the inner flow-limiting ring and the outer flow-limiting ring along the axial direction. When the plunger descends in a shut-in state, the relative speed of the plunger and the fluid is low, so that the fluid can easily pass through a tortuous flow passage formed between the inner flow limiting column and the outer flow limiting pipe, namely, the fluid can easily flow from the lower part of the plunger to the upper part of the plunger. This reduces the resistance of the fluid to the plunger, which can descend smoothly when the well is shut in. When the plunger moves upwards in the open-hole state, the relative speed of the plunger and the fluid is high, so that the fluid is difficult to pass through a tortuous flow passage formed between the inner flow limiting column and the outer flow limiting pipe, the fluid leakage amount is reduced, and the lifting efficiency can be maintained at a high level.

One of the flow limiting column and the outer flow limiting pipe is fixedly arranged, and the other one of the flow limiting column and the outer flow limiting pipe can move axially. When the plunger moves downwards in a well closing state, if the fluid resistance is overlarge, the plunger can push the axially movable piston to move axially, so that the inner flow limiting ring is contacted with the outer flow limiting ring, a tortuous flow passage formed between the inner flow limiting column and the outer flow limiting pipe is closed, and the plunger stops moving downwards under the action of the fluid resistance. At the moment, because the flow rate of the fluid is low, the relative speed of the plunger and the fluid is basically 0, the axially movable plunger moves downwards under the action of self gravity, the inner flow limiting ring is separated from the outer flow limiting ring, a tortuous flow passage formed between the inner flow limiting column and the outer flow limiting tube is opened, the fluid can flow from the lower part of the plunger to the upper part of the plunger, the resistance of the fluid to the plunger is reduced, and the plunger can continuously move downwards. When the plunger moves downwards, the relative speed of the plunger and the fluid is increased, the fluid resistance is increased, and the axially movable plunger is pushed to move axially. By doing so, the plunger can smoothly descend to the bottom of the well. When the plunger piston moves upwards in the open-hole state, because the flow rate of the fluid is high, the relative speed of the plunger piston and the fluid is high, the plunger piston can move axially under the action of the thrust of the fluid to enable the inner flow limiting ring and the outer flow limiting ring to be contacted, a tortuous flow passage formed between the inner flow limiting column and the outer flow limiting pipe is closed, leakage caused by a fluid passage is avoided, and the lifting efficiency can be maintained at a high level.

The inner flow limiting column is arranged in the outer flow limiting pipe in an axially adjustable position, so that the size of a gap between the inner flow limiting ring and the outer flow limiting ring can be freely adjusted. The size of the gap between the inner flow limiting ring and the outer flow limiting ring is adjusted according to the energy condition of the well bottom, so that the plunger can smoothly descend, and the lifting efficiency can be maintained at a higher level. When the energy at the bottom of the well is enough, the gap between the inner flow restricting ring and the outer flow restricting ring can be properly increased. When the energy at the bottom of the well is relatively insufficient, the gap between the inner flow restricting ring and the outer flow restricting ring can be properly reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments are briefly described below. It is appreciated that the following drawings depict only certain embodiments of the application and are not to be considered limiting of its scope. From these figures, other figures can be derived by those skilled in the art without inventive effort.

Fig. 1 is a schematic external structural view of a plunger according to embodiment 1 of the present application;

fig. 2 is a schematic structural diagram of a core in the plunger provided in embodiment 1 of the present application;

fig. 3 is a schematic cross-sectional view of a plunger according to embodiment 1 of the present application;

fig. 4 is a schematic view of a split structure of an end face of an outer current-limiting pipe in embodiment 1 of the present application;

fig. 5 is a schematic cross-sectional view of a plunger according to embodiment 2 of the present application;

fig. 6 is a schematic cross-sectional view of a plunger according to embodiment 3 of the present application.

In the figure: 010-a plunger; 100-a core; 100 a-a workspace; 100 b-a tortuous flow path; 110-upper end; 111-upper connection hole; 112-upper fluid hole; 120-lower end; 121-lower connection hole; 122-lower fluid orifice; 123-a guide hole; 124-internal threaded through hole; 130-core tube; 131-an inner positioning groove; 132-a fluid channel; 200-a sealing gasket; 210-outer positioning groove; 300-a first elastic return member; 400-an outer current limiting pipe; 410-outer restrictor ring; 500-inner flow-limiting column; 510-inner restrictor ring; 520-a guide post; 530-screw; 540-locking the nut.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described in detail and completely with reference to the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all embodiments.

Thus, the following detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but is merely representative of some embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that, in the embodiments and the features and technical solutions in the embodiments of the present application may be combined with each other without conflict.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it should be noted that the terms "upper", "lower", and the like refer to orientations or positional relationships based on those shown in the drawings, or orientations or positional relationships that are conventionally arranged when the product of the present invention is used, or orientations or positional relationships that are conventionally understood by those skilled in the art, and such terms are used for convenience of description and simplification of the description, and do not refer to or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.

In the description of the present application, "oil and gas well" may refer to both oil and gas wells. When the "oil and gas well" is a natural gas well, it may be a natural gas well for collecting conventional natural gas, or a natural gas well for collecting unconventional natural gas (shale gas, coal bed gas, etc.).

Example 1:

fig. 1 is a schematic view of an external structure of the plunger 010 provided in this embodiment. Fig. 2 is a schematic structural diagram of a core 100 in a plunger 010 according to an embodiment of the present disclosure. Fig. 3 is a schematic cross-sectional structure diagram of the plunger 010 provided in this embodiment. Referring to fig. 1 and 2, in the present embodiment, the plunger 010 includes a core 100, a sealing gasket 200, a first elastic restoring member 300, an outer flow restricting tube 400, and an inner flow restricting post 500.

The core body 100 includes an upper end head 110, a lower end head 120, and a core tube 130. One end of the upper end 110 is provided with an upper connection hole 111, and an internal thread is arranged in the upper connection hole 111. An upper fluid hole 112 is formed in a side surface of the upper head 110, and the upper fluid hole 112 extends in a radial direction and communicates the upper connection hole 111 with the outside. One end of the lower end 120 is provided with a lower connecting hole 121, and an internal thread is arranged in the lower connecting hole 121. The lower fluid hole 122 is formed in the side surface of the lower end 120, and the lower fluid hole 122 extends in the radial direction and communicates the lower connection hole 121 with the outside. The inner space of the core tube 130 constitutes a fluid passage 132. The fluid passage 132 communicates with the upper fluid hole 112 through the upper connection hole 111. The fluid passage 132 communicates with the lower fluid hole 122 through the lower connection hole 121.

The upper end head 110 and the lower end head 120 form a working space 100a around the core tube 130 therebetween. A plurality of sealing gaskets 200 are positioned in the work space 100a and are disposed around the core tube 130. The first resilient return member 300 acts on the sealing gasket 200 to provide the sealing gasket 200 with a tendency to move radially outwardly. When no external force is applied, the first elastic restoring member 300 drives the sealing gasket 200 to move radially outward. Under the action of the radially inward external force, the sealing gasket 200 can move radially inward against the elastic force of the first elastic restoring member 300. In this embodiment, the first elastic restoring member 300 is a spring and is disposed between the sealing gasket 200 and the core tube 130, and the first elastic restoring member 300 is always in a compressed state, so that the sealing gasket 200 always has a tendency to move radially outward. Specifically, the inner surface of the sealing gasket 200 is provided with an outer positioning groove 210, and the outer circumferential surface of the core tube 130 is provided with an inner positioning groove 131 facing the outer positioning groove 210. The two ends of the first elastic restoring member 300 are respectively located in the outer positioning groove 210 and the inner positioning groove 131.

An outer restrictor tube 400 is disposed in the fluid passage 132, the outer restrictor tube 400 extending in the axial direction of the core tube 130. The inner circumferential surface of the outer restrictor pipe 400 is provided with a plurality of outer restrictor rings 410 protruding radially inward. A plurality of outer restrictor rings 410 are spaced axially along the outer restrictor tube 400. The inner current-limiting column 500 is disposed inside the outer current-limiting pipe 400, and the inner current-limiting column 500 extends in the axial direction of the core tube 130. The inner flow restriction column 500 has a diameter less than the inner diameter of the outer flow restriction ring 410. The outer circumferential surface of the inner post 500 is provided with a plurality of inner flow restricting rings 510 protruding radially outward. A plurality of inner flow restricting rings 510 are spaced along the axis of the inner flow restricting post 500. Wherein the inner restrictor rings 510 and the outer restrictor rings 410 are alternately arranged in the axial direction. That is, in the axial direction, one inner restrictor ring 510 exists between two adjacent outer restrictor rings 410, and one outer restrictor ring 410 exists between two adjacent inner restrictor rings 510. The outer diameter of the inner restrictor ring 510 is larger than the inner diameter of the outer restrictor ring 410. The outer diameter of the inner restrictor ring 510 is smaller than the inner diameter of the outer restrictor tube 400. The spacing between adjacent outer flow restricting rings 410 is greater than the thickness of the inner flow restricting ring 510.

In this embodiment, the outer current limiting pipe 400 and the inner current limiting column 500 are both fixedly disposed. Specifically, both ends of the outer flow restrictor tube 400 abut against the upper and

lower headers

110 and 120, respectively, so that the outer flow restrictor tube 400 is fixedly disposed in the fluid passage 132. Both ends of the inner current-limiting column 500 are also abutted against the upper and

lower headers

110 and 120, respectively, so that the inner current-limiting column 500 is fixedly disposed in the outer current-limiting tube 400. In the axial direction, a gap exists between the inner restrictor ring 510 and the outer restrictor ring 410. In this manner, a tortuous flow passage 100b is formed between the outer flow restricting tube 400 and the inner flow restricting post 500. The fluid can flow from below the plunger 010 to above the plunger 010 through the lower fluid hole 122, the meandering flow passage 100b, and the upper fluid hole 112 in this order. The fluid can flow from above the plunger 010 to below the plunger 010 through the upper fluid hole 112, the meandering flow path 100b, and the lower fluid hole 122 in this order.

When the plunger 010 descends in the shut-in state, the relative velocity of the plunger 010 to the fluid is low, which enables the fluid to easily pass through the tortuous flow passage 100b formed between the inner flow restricting post 500 and the outer flow restricting post 400, i.e., the fluid can easily flow from below the plunger 010 to above the plunger 010. This reduces the resistance of the fluid to the plunger 010, allowing the plunger 010 to descend smoothly when shutting in the well. When the plunger 010 moves upward in the open-hole state, the relative velocity of the plunger 010 to the fluid is high, which makes it difficult for the fluid to pass through the tortuous flow passage 100b formed between the inner restrictor column 500 and the outer restrictor tube 400, thereby ensuring that the amount of fluid lost is maintained at a low level, i.e., the fluid is difficult to flow from below the plunger 010 to above the plunger 010 and difficult to flow from above the plunger 010 to below the plunger 010. This ensures that the lifting efficiency can be maintained at a high level.

In the present embodiment, the outer circumferential surface of the outer restrictor tube 400 is in contact with the inner circumferential surface of the fluid passage 132, which enables the fluid to flow from above to below of the plunger 010 or from below to above of the plunger 010 only through the meandering flow passage 100 b. This helps reduce the leakage when the plunger 010 is moved upward.

Fig. 4 is a schematic view of a split structure of an end surface of the external flow limiting pipe 400 in this embodiment. Referring to fig. 4, in the present embodiment, the outer flow restrictor 400 includes two portions that are independent and symmetrical to each other in the radial direction. Similarly, the outer restrictor ring 410 includes two radially independent and symmetrical portions. This enables the plunger 010 provided by the present embodiment to be simply assembled. The left and right parts of the outer restrictor 400 are fastened to the inner restrictor column 500 such that the inner restrictor rings 510 and the outer restrictor rings 410 are alternately arranged. The outer current limiting pipe 400 and the inner current limiting post 500 are then inserted into the core pipe 130 as a whole. After the upper and

lower headers

110 and 120 are assembled, the positions of the outer current-limiting pipe 400 and the inner current-limiting column 500 are fixed.

In the present embodiment, the plurality of outer restrictor rings 410 are arranged at equal intervals in the axial direction, and the plurality of inner restrictor rings 510 are arranged at equal intervals in the axial direction; the spacing between adjacent outer flow restricting rings 410 is equal to the spacing between adjacent inner flow restricting rings 510. It is understood that in other embodiments, the spacing between adjacent outer restrictor rings 410 may not be equal, the spacing between adjacent inner restrictor rings 510 may not be equal, and the spacing between outer restrictor rings 410 and the spacing between inner restrictor rings 510 may not be equal.

Example 2:

fig. 5 is a schematic cross-sectional structure diagram of the plunger 010 provided in this embodiment. The plunger 010 of the present embodiment is substantially the same as that described in embodiment 1, except that in the present embodiment, one of the inner restrictor post 500 and the outer restrictor tube 400 is fixedly disposed, and the other is axially movably disposed.

Specifically, in the present embodiment, the inner current-limiting column 500 is axially movably disposed, and the outer current-limiting pipe 400 is fixedly disposed. The outer flow restrictor 400 is fixedly disposed in the manner described in embodiment 1.

When the plunger 010 descends in a well shut-in state, if the fluid resistance is too large, the inner current-limiting column 500 is pushed to move axially, so that the inner current-limiting ring 510 is in contact with the outer current-limiting ring 410, the tortuous flow passage 100b formed between the inner current-limiting column 500 and the outer current-limiting pipe 400 is closed, and the plunger 010 stops descending under the action of the fluid resistance. At this time, since the flow rate of the fluid is slow, the relative velocity between the plunger 010 and the fluid is substantially 0, the inner restrictor column 500 moves downward by its own weight, the inner restrictor ring 510 and the outer restrictor ring 410 are separated, the tortuous flow passage 100b formed between the inner restrictor column 500 and the outer restrictor tube 400 is opened, and the fluid can flow from below the plunger 010 to above the plunger 010, which reduces the resistance of the fluid to the plunger 010, and the plunger 010 can continue to move downward. When the plunger 010 moves downwards, the relative speed between the plunger 010 and the fluid is increased, and the fluid resistance is increased along with the increase of the relative speed, so that the inner flow limiting column 500 is pushed to move axially. Reciprocating in this way, the plunger 010 can smoothly go down to the bottom of the well. When the plunger 010 moves upwards in the open-hole state, due to the fact that the flow rate of the fluid is high, the relative speed of the plunger 010 and the fluid is high, the inner flow limiting column 500 moves axially under the action of the thrust of the fluid, the inner flow limiting ring 510 is in contact with the outer flow limiting ring 410, the bent flow channel 100b formed between the inner flow limiting column 500 and the outer flow limiting pipe 400 is closed, leakage caused by the fluid channel 132 is avoided, and the lifting efficiency can be maintained at a high level.

It is understood that in other embodiments, the outer flow restricting tube 400 may be axially movably disposed and the inner flow restricting column 500 may be fixedly disposed.

In this embodiment, the plunger 010 further includes a guide post 520 extending in the axial direction. The guide posts 520 are connected to the lower ends of the inner flow restricting posts 500. The lower end 120 is provided with a guide hole 123 extending along the axial direction. Guide posts 520 slidably engage guide holes 123. Through the cooperation of guide post 520 and guiding hole 123, can ensure that interior current-limiting post 500 moves along the axial, improve the operational reliability of plunger 010. It is understood that in other embodiments, the guide post 520 may be attached to the upper end of the inner flow restriction post 500 and the guide hole 123 may begin in the upper head 110.

Example 3:

fig. 6 is a schematic cross-sectional structure diagram of the plunger 010 provided in this embodiment. The plunger 010 of the present embodiment is substantially the same as that described in embodiment 1, except that in the present embodiment, one of the inner restrictor post 500 and the outer restrictor tube 400 is fixedly disposed, and the other is axially adjustable in position.

Specifically, in the present embodiment, the inner restrictor post 500 is axially adjustable in position and the outer restrictor tube 400 is fixed. The outer flow restrictor 400 is fixedly disposed in the manner described in embodiment 1.

By adjusting the axial position of the inner post 500, the size of the gap between the inner and outer

flow restricting rings

510 and 410 can be freely adjusted. The size of the gap between the inner restrictor ring 510 and the outer restrictor ring 410 is adjusted according to the energy condition at the bottom of the well, so that the plunger 010 can smoothly descend and the lifting efficiency can be maintained at a high level. When the downhole energy is sufficient, the gap between the inner restrictor ring 510 and the outer restrictor ring 410 may be increased appropriately. When the energy at the bottom of the well is relatively scarce, the gap between the inner restrictor ring 510 and the outer restrictor ring 410 can be reduced appropriately.

It is understood that in other embodiments, the outer restrictor tube 400 may be axially adjustable in position and the inner restrictor post 500 may be fixed.

In this embodiment, plunger 010 further includes an axially extending threaded rod 530. A screw 530 is connected to the lower end of the inner flow restricting column 500. The lower end 120 is provided with an internal threaded through hole 124 extending along the axial direction. The threaded rod 530 is threadedly engaged with the internally threaded through bore 124. By rotating the screw 530, the position of the inner restrictor ring 510 can be adjusted, thereby adjusting the size of the gap between the inner restrictor ring 510 and the outer restrictor ring 410. It is understood that in other embodiments, the threaded rod 530 may be attached to the upper end of the inner flow restriction column 500 and the internally threaded through bore 124 may begin at the upper head 110.

Further, in the present embodiment, the screw 530 penetrates the internally threaded through hole 124 and extends to the outside of the core 100. In this manner, the screw 530 can be conveniently rotated to adjust the size of the gap between the inner restrictor ring 510 and the outer restrictor ring 410.

Further, in this embodiment, the plunger 010 further includes a lock nut 540, and the lock nut 540 is threadedly coupled to a portion of the screw 530 located outside the core 100. After the size of the gap between the inner restrictor ring 510 and the outer restrictor ring 410 is adjusted in place, the lock nut 540 is screwed, so that the gap between the inner restrictor ring 510 and the outer restrictor ring 410 can be prevented from being changed in the working process of the plunger 010, and the working reliability of the plunger 010 is improved.

The above description is only a few examples of the present application and is not intended to limit the present application, and those skilled in the art will appreciate that various modifications and variations can be made in the present application. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A plunger, comprising:

the fluid channel axially extending along the core body is arranged in the core body, and an upper fluid hole and a lower fluid hole which are communicated with the fluid channel and the outside are respectively formed in the two axial ends of the core body;

a plurality of sealing gaskets arranged around the core and configured to reciprocate in a radial direction;

a first elastic restoring member acting on the sealing gasket and configured to exert a radially outward elastic force on the sealing gasket;

the outer flow limiting pipe is arranged in the fluid channel, the inner circumferential surface of the outer flow limiting pipe is provided with a plurality of outer flow limiting rings which radially and inwards protrude, and the outer flow limiting rings are axially arranged at intervals; and

the outer peripheral surface of the inner flow limiting column is provided with a plurality of inner flow limiting rings which protrude outwards in the radial direction, and the inner flow limiting rings are arranged at intervals in the axial direction;

wherein the inner restrictor rings and the outer restrictor rings are alternately arranged along the axial direction; the outer diameter of the inner flow limiting ring is larger than the inner diameter of the outer flow limiting ring; the outer diameter of the inner flow limiting ring is smaller than the inner diameter of the outer flow limiting pipe; the distance between the adjacent outer flow restricting rings is larger than the thickness of the inner flow restricting ring.

2. The plunger of claim 1, wherein:

the inner current limiting column and the outer current limiting pipe are both fixedly arranged; in the axial direction, a gap exists between the inner restrictor ring and the outer restrictor ring.

3. The plunger of claim 1, wherein:

one of the inner flow limiting column and the outer flow limiting pipe is fixedly arranged, and the other one of the inner flow limiting column and the outer flow limiting pipe can be axially movably arranged.

4. The plunger of claim 3, wherein:

the plunger further comprises a guide post extending along the axial direction, one end of the core body is provided with a guide hole extending along the axial direction, and the guide post is matched with the guide hole in a sliding manner;

the guide post is connected with one of the inner flow limiting post and the outer flow limiting pipe which can move axially.

5. The plunger of claim 1, wherein:

one of the inner flow limiting column and the outer flow limiting pipe is fixedly arranged, and the other one of the inner flow limiting column and the outer flow limiting pipe can be axially adjusted in position.

6. The plunger of claim 5, wherein:

the plunger further comprises a screw rod extending along the axial direction, and one end of the core body is provided with an internal thread through hole extending along the axial direction; the screw rod is in threaded fit with the internal threaded hole;

the screw is connected with one of the inner flow-restricting column and the outer flow-restricting tube at an axially adjustable position.

7. The plunger of claim 6, wherein:

the screw extends outside the core.

8. The plunger of claim 7, wherein:

the plunger piston also comprises a locking nut, and the locking nut is in threaded connection with the part of the screw rod, which is positioned outside the core body.

9. The plunger of claim 1, wherein:

the outer circumferential surface of the outer flow limiting pipe is in contact with the inner circumferential surface of the fluid passage.

10. The plunger of claim 1, wherein:

in the radial direction, the outer flow limiting pipe comprises two parts which are independent and symmetrical with each other.

11. The plunger of claim 1, wherein:

the outer restrictor rings are arranged at equal intervals in the axial direction, and the inner restrictor rings are arranged at equal intervals in the axial direction; the distance between the adjacent outer flow restricting rings is equal to the distance between the adjacent inner flow restricting rings.