CN115628194A - Submersible reverse-driving single-cylinder single-suction double-row reciprocating plunger pump - Google Patents

Abstract

The invention relates to a submersible reverse-driven single-cylinder single-suction double-row reciprocating plunger pump, belonging to the technical field of pumps. The pump comprises a pump body, a reciprocating driving mechanism and a plunger; the reciprocating driving mechanism drives the plunger through the transmission rod; the plunger cavity comprises a large-diameter cavity and a small-diameter cavity forming a liquid discharge cavity, and the lower port part of the small-diameter cavity is of a plunger hole structure; the plunger comprises a small-diameter plunger part and a large-diameter plunger part, and the outer diameter of the small-diameter plunger part is larger than that of the transmission rod; the large-diameter plunger part is in clearance seal fit with the large-diameter chamber to divide the large-diameter chamber into a liquid inlet chamber part and a transfer chamber part; the plunger is provided with a liquid discharge channel and a liquid inlet channel which are correspondingly used for communicating the small-diameter cavity with the transfer cavity part and for communicating the liquid inlet cavity part with the transfer cavity part; the liquid discharge channel is provided with a check valve for liquid discharge, and the liquid inlet channel is provided with a check valve for liquid suction. The pump has the advantages that the solution medium is discharged in the up-down stroke of the plunger, the balance of equipment is improved, and the pump can be used in the fields of oil exploitation and the like.

Description

Submersible reverse-driven single-cylinder single-suction double-row reciprocating plunger pump

Technical Field

The invention relates to the technical field of pumps, in particular to a submersible type reverse-drive single-cylinder single-suction double-row reciprocating plunger pump.

Background

In the field of petroleum production and the like, solution media such as underground petroleum need to be pumped to the ground through an oil well pump; for the concrete structure of the oil well pump, a plunger pump is usually adopted for construction, for example, an axial plunger pump with publication number CN110578663A is adopted for construction, and the axial plunger pump mainly has the advantages of compact structure, good process, small volume, light weight, high discharge pressure and the like.

The pump body structure of the plunger pump can be specifically constructed by adopting the pump body structure 01 shown in fig. 1 and fig. 2, wherein the pump body structure 01 comprises a pump body 02 provided with a plunger chamber 020, a plunger 04 which is arranged in the plunger chamber 020 in a reciprocating manner along the axial direction, and a reciprocating driving mechanism positioned on the ground; the reciprocating driving mechanism is generally constructed by a gouging machine arranged on the ground.

In order to drive the plunger 04 of the underground plunger pump, the reciprocating drive mechanism drives the plunger 04 to reciprocate vertically through the transmission rod 05 extending into the plunger chamber 020. In this embodiment, a sleeving connection hole 043 for sleeving connection with the transmission rod 05 is arranged on the plunger 04, and other connection modes can be adopted for fixed connection.

As shown in fig. 1 and 2, the plunger 04 during moving divides the plunger chamber 020 into a liquid inlet cavity 021 and a liquid outlet cavity 022, wherein the liquid inlet cavity 021 is communicated with the outside through a liquid inlet hole 023 arranged on the pump body 02, and the liquid outlet cavity 022 is communicated with the outside through a liquid outlet hole arranged on the pump body 02; an upper drainage channel 042 and a lower drainage channel 041 which are vertically arranged are arranged in the plunger, and the upper drainage channel 042 and the lower drainage channel 041 form a drainage channel 040 for communicating the liquid inlet cavity 021 with the liquid outlet cavity 022; a liquid discharge one-way valve 032 used for non-return and used for preventing the solution medium from flowing back to the liquid inlet cavity 021 from the liquid discharge cavity 022 is arranged in the liquid discharge channel 040; and a liquid-sucking check valve 031 for stopping the flow of the solution medium from the liquid inlet chamber 021 to the outside is arranged on the liquid inlet hole 023.

When the plunger pump is used, when the reciprocating drive mechanism drives the plunger 04 to move upwards through the transmission rod 05, the liquid inlet cavity 021 generates negative pressure to open the liquid suction check valve 031, so that external solution media such as petroleum enter the liquid inlet cavity 021 through the liquid inlet hole 023; the plunger 04 moving upward compresses the volume of the liquid discharge lumen 022 to close the liquid discharge check valve 032 and close the liquid discharge path 040, thereby discharging the liquid discharge lumen 022 to the outside through the liquid discharge hole. Therefore, underground solution media such as petroleum are pumped to the ground, but in the using process, the following problems exist, and the adoption of the reciprocating driving mechanism arranged above brings about larger land occupation area and increases the investment cost; the main problems are that only oil is discharged in the lifting process during the use process, the power distribution of the power of the driving mechanism is uneven in the use process, the problem of large driving force pulsation is caused, the transmission rod is contacted with an oil rod and the like to generate eccentric wear force, and the service life of equipment is shortened.

In order to solve the problems, a submerged back-driven plunger pump is generally adopted, and four one-way ball valves are configured as check valves, but the check valves are limited by the structural size of a product, the arrangement is extremely difficult, the manufacturability is poor, and the number of faults is large.

Disclosure of Invention

The invention mainly aims to provide a reciprocating plunger pump driven by a submerged type in a reverse direction, so that a double-row function can be realized based on single cylinder and single suction in the using process, the power balance of driving equipment can be effectively improved, and the layout of the submerged type in the reverse direction is better realized;

another object of the present invention is to provide a submersible back-driving single-cylinder, single-suction, double-row reciprocating plunger pump that achieves substantially double-uniform-row based on single-cylinder, single-suction during use.

In order to realize the main purpose, the reciprocating plunger pump provided by the invention is a submersible type reverse-driven single-cylinder single-suction double-row plunger pump; the plunger pump comprises a pump body provided with a plunger cavity, a reciprocating driving mechanism and a plunger which can be vertically movably arranged in the plunger cavity; the reciprocating driving mechanism is positioned at the lower side of the pump body and drives the plunger to reciprocate based on the transmission rod; the transmission rod passes through a through hole arranged on the pump body in a liquid-tight manner; from bottom to top, the plunger cavity comprises a large-diameter cavity and a small-diameter cavity forming a liquid discharge cavity; the small-diameter cavity is communicated with the outside through a liquid discharge hole arranged on the pump body and comprises a section part in a plunger hole structure; the plunger comprises a small-diameter plunger part and a large-diameter plunger part which are vertically arranged and fixedly connected, and the outer diameter of the small-diameter plunger part is larger than that of the transmission rod; the small-diameter plunger part is in clearance sealing fit with the plunger hole structure, and liquid sealing is carried out on the small-diameter cavity; the large-diameter plunger part is in clearance sealing fit with the large-diameter cavity; the movable large-diameter plunger part divides the large-diameter chamber into a liquid inlet chamber part with variable volume and a transfer chamber part from top to bottom; the liquid inlet cavity part is communicated with the outside through a liquid inlet hole arranged on the pump body; a liquid inlet channel and a lower liquid discharge channel part which are vertically arranged are arranged in the large-diameter plunger part, and an upper liquid discharge channel part is arranged on the small-diameter plunger part; the upper drainage channel and the lower drainage channel are butted to form a drainage channel which is used for communicating the small-diameter cavity with the middle rotating cavity; the liquid inlet channel is used for communicating the liquid inlet cavity part with the transfer cavity part; the liquid discharge channel is provided with a check valve for liquid discharge for non-return, and the liquid inlet channel is provided with a check valve for liquid suction for non-return.

In the technical scheme, the structure of the internal plunger cavity of the pump body and the structure of the plunger are improved, and the plunger cavity is mainly formed by arranging a large-diameter cavity and a small-diameter cavity which are communicated with each other, correspondingly arranging the plunger into a small-diameter plunger part and a large-diameter plunger part which are fixedly connected, and arranging a liquid discharge channel and a liquid inlet channel in the plunger; therefore, in the working process, when the reciprocating driving mechanism drives the plunger piston to move upwards through the transmission rod, the non-return of the one-way valve for liquid drainage closes the liquid drainage channel, so that negative pressure is generated in the transfer cavity part to open the one-way valve for liquid suction, and the liquid inlet channel is opened, so that solution media such as petroleum and the like are sucked into the transfer cavity part; meanwhile, the small-diameter plunger part occupies part of the small-diameter cavity, so that the solution medium is discharged from the liquid discharge hole. When the reciprocating driving mechanism drives the plunger to move downwards through the transmission rod, the liquid drainage check valve is opened to open the liquid drainage channel, the liquid suction check valve is stopped to close the liquid inlet channel, the small-diameter plunger part exits part of the small-diameter cavity, so that the solution medium enters the liquid drainage cavity from the rotating cavity, and the outer diameter of the small-diameter plunger part is larger than that of the transmission rod, so that the volume of the solution medium entering the liquid drainage cavity is larger than that of the liquid drainage cavity, which is newly increased due to the exit of the small-diameter plunger part, so that part of the solution medium is discharged from the liquid drainage hole, and the solution medium is discharged from the liquid drainage hole in the upward and downward moving strokes of the plunger.

The pump body comprises a small-diameter cavity and a large-diameter cavity, wherein the small-diameter cavity is used for enclosing a small-diameter cavity, and the large-diameter cavity is used for enclosing a large-diameter cavity; the upper port part of the large-diameter cavity is of an open structure; the small-diameter cavity is in butt joint with the large-diameter cavity, so that the large-diameter cavity is communicated with the small-diameter cavity.

More specifically, the lower port of the small-diameter cavity is sleeved in the upper port in a liquid-tight manner.

The preferred scheme is that the drain hole is arranged at the top of the pump body.

The preferred scheme is that a plurality of liquid inlet holes are uniformly distributed along the circumferential direction of the pump body.

The preferred scheme is that the pump body is of a cylindrical structure, and the small-diameter cavity and the large-diameter cavity are both of a circular cavity structure.

The preferable proposal is that the small-diameter chamber comprises a containing chamber part, and the containing chamber part is positioned at the adjacent upper side of the plunger hole structure; the lower port part of the small-diameter chamber is a plunger hole structure in clearance seal fit with the small-diameter plunger; on a plane perpendicular to the vertical direction, the projections of the cavity walls of the accommodating cavity parts are located outside the projection of the plunger hole structure, and the difference is more than a preset interval. The technical scheme can be convenient for processing the structure of the pump body with the small-diameter cavity.

In order to achieve the above-mentioned another object, the present invention provides a preferable mode in which the ratio of the liquid suction volume to the liquid discharge volume is 1.9 to 2.1 during the upward movement of the plunger relative to the pump body by a unit pitch; the imbibing volume is the volume of the solution medium absorbed into the transfer chamber part in the process of moving the plunger upwards; the drain volume is the volume of solution medium drained from the small diameter chamber during upward movement of the plunger.

In the technical scheme, based on the preset structure and size ratio of the plunger and the transmission rod, the ratio of the liquid suction volume to the liquid discharge volume is 1.9-2.1, so that double uniform discharge in upward and downward strokes of the plunger is approximately realized, namely, the volumes of solution media discharged in the two strokes are approximately the same.

A further solution is that the ratio of the liquid intake volume to the liquid discharge volume is 2.

In order to achieve the above another object, the present invention provides a preferable solution that the dimensions of the plunger and the transmission rod satisfy a ratio of the first value to the second value of 1.95 to 2.05; the first value is the difference between the square of the radius of the large-diameter plunger and the square of the radius of the transmission rod, and the second value is the square of the radius of the small-diameter plunger.

In the technical scheme, based on the preset structure and size ratio of the plunger and the transmission rod, double uniform discharge in upward and downward strokes of the plunger is approximately realized, that is, the volumes of solution media discharged in the two strokes are approximately the same.

Drawings

Fig. 1 is a schematic structural view of a conventional plunger pump;

FIG. 2 is a schematic diagram of a plunger of the plunger pump of FIG. 1;

FIG. 3 is a schematic diagram of a plunger pump according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a plunger according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a plunger according to an embodiment of the present invention;

FIG. 6 is a schematic view of the structure of the plunger and the transmission rod in the embodiment of the present invention;

FIG. 7 is a schematic diagram of the downward movement stroke of the plunger according to the embodiment of the present invention;

fig. 8 is a schematic structural view of an upward movement stroke of the plunger in the embodiment of the invention.

Detailed Description

The present invention will be further described with reference to the following examples and the accompanying drawings.

The main concept of the invention is to improve the structure of the existing plunger pump to construct a submersible type back-driven single-cylinder single-suction double-row reciprocating plunger pump, so that in the process of pumping solution media such as crude oil, the solution media can be pumped based on a half stroke in a reciprocating stroke, and the solution media are discharged in the whole reciprocating stroke, thereby improving the driving balance of driving equipment. Based on the main concept, the structure and shape of the pump body are not limited to the schematic structure in the following embodiments, for example, a non-circular cross-sectional structure may be adopted, the number and the structural size of the liquid discharge channels and the liquid inlet channels are configured according to actual needs, and the small-diameter cavity and the large-diameter cavity in the cavity structure are arranged, processed and connected according to actual needs.

Examples

Referring to fig. 3 to 8, the reciprocating plunger pump 1 of the present invention is a single-cylinder single-suction double-row submersible reverse drive, i.e. the discharge of the solution medium in the whole process can be realized based on the single suction of a single plunger. Structurally, the reciprocating plunger pump 1 includes a pump body 2 provided with a plunger chamber 9, a reciprocating drive mechanism not shown in the drawings, and a plunger 3 vertically movably disposed in the plunger chamber 9. In the present embodiment, the main structures of the plunger 4, the plunger chamber 9 and the pump body 2 are all cylindrical structures, and may be configured into other shapes according to actual needs. The specific structure of the reciprocating drive mechanism can be designed by referring to the existing products, and for example, a reciprocating drive mechanism disclosed in patent document CN110578663A is adopted.

In order to construct a submerged type reverse driving structure, the reciprocating driving mechanism is configured to be positioned at the lower side of the pump body 2, namely, the reciprocating driving mechanism is vertically positioned below the pump body 2 to enter the ground together with the pump body 2 in the using process, so that the occupation of the ground land source is effectively reduced, and at the moment, if the underground arrangement scheme of the reciprocating driving mechanism can be well realized if the solution medium is discharged in the whole process based on single-cylinder single suction. In this technical solution, in this embodiment, the plunger 3 is driven to reciprocate vertically by the transmission rod 11, specifically, the transmission rod 11 passes through a through hole provided on the pump body 2 and enters the plunger cavity 9 of the pump body 2 from the outside, and by arranging the sealing device 42 and the sealing device mounting bracket 41 on the pump body, the arrangement of the liquid-tight through hole is realized, so as to realize the sealing arrangement between the transmission rod 11 and the pump body 2. As shown in fig. 4 and 5, in order to facilitate the connection between the transmission rod 11 and the plunger 3, a rod fitting hole 53 for fitting and connecting the upper end of the transmission rod 11 is provided in the lower end of the plunger.

As shown in fig. 3 to 8, the specific structure of the plunger chamber 9 includes, from bottom to top, a large-diameter chamber 20 and a small-diameter chamber 70 which are connected in an abutting manner, wherein the small-diameter chamber 70 constitutes a liquid discharge chamber in this embodiment, and the small-diameter chamber 70 is connected to the outside through a liquid discharge hole 71 provided in the pump body 2, so as to discharge a solution medium such as crude oil, cement slurry, etc. to the outside of the plunger chamber 9. In this embodiment, in order to facilitate clearance seal fit between the small-diameter chamber 70 and the plunger 3 and achieve a liquid seal effect, the lower end opening portion of the small-diameter chamber 70 is provided with a plunger hole structure 701; the plunger hole structure 701 can be set into a middle area or an upper section area according to actual needs, and the middle area or the upper section area is set into clearance sealing fit with the plunger 3, and the liquid drainage requirement only needs to be met.

As for the specific structure of the plunger 3, as shown in fig. 3 to 8, corresponding to the structure of the plunger chamber 9 with the vertically distributed large and small diameters, the plunger 3 comprises a large-diameter plunger part 5 and a small-diameter plunger part 6 which are fixedly connected, and the outer diameter of the small-diameter plunger part 6 is larger than that of the transmission rod 11, so that the solution medium can be output from the liquid discharge hole 71 in the full stroke. In the working process, the small-diameter plunger part 6 is in clearance seal fit with the lower end opening part of the small-diameter chamber 70 forming the plunger hole structure 701, and liquid seal is carried out on the lower end opening of the small-diameter chamber 70, so that the isolation between the large-diameter chamber 20 and the small-diameter chamber 70 is realized, and the influence on the pumping effect caused by the direct circulation of solution media such as crude oil and the like between the large-diameter chamber 20 and the small-diameter chamber 70 is avoided. In the working process, the large-diameter plunger part 5 is in clearance sealing fit with the large-diameter chamber 20, and the movable large-diameter plunger part 5 divides the large-diameter chamber 20 into a liquid inlet chamber part 201 and a transfer chamber part 202, the volumes of which can be changed along with the movement of the large-diameter plunger part 5, in the direction from top to bottom; the liquid inlet cavity 201 is directly communicated with the outside through a liquid inlet hole 21 formed in the pump body 2, that is, a solution medium such as crude oil enters the plunger cavity 20, specifically, the inside of the liquid inlet cavity 201, through the liquid inlet hole 21 under the action of pressure. In the present embodiment, the structural size, number and specific position of the liquid inlet hole 21 and the liquid outlet hole 71 can be configured according to actual needs; in the present embodiment, the drain holes 71 are arranged on the top of the pump body 2, and the plurality of liquid inlet holes 21 are uniformly distributed along the circumferential direction of the pump body 2.

In order to realize the transportation of solution media such as crude oil to the small-diameter chamber 70 forming the liquid discharge chamber through the intermediate transfer chamber part 202, the liquid inlet channel 51 and the lower liquid discharge channel part 52 are arranged in the large-diameter plunger part 5, and the upper liquid discharge channel part 61 is arranged on the small-diameter plunger part 6; the specific structure of the liquid inlet passage 51, the lower liquid discharge passage 52, and the upper liquid discharge passage 61 may be constructed by a duct structure directly formed inside the plunger structure, or may be constructed by a pipe arranged therein. The upper drainage channel 61 and the lower drainage channel 52 are directly butted to form the drainage channel 8 in the embodiment, and are used for communicating the small-diameter chamber 70 with the transfer chamber part 202; the liquid inlet channel 51 is used for communicating the liquid inlet cavity 201 with the transfer cavity 202; in order to avoid the backflow problem of the solution medium in the conveying process, a liquid discharging one-way valve 44 for non-return and a liquid sucking one-way valve 43 for non-return are distributed on the liquid discharging channel 8 and the liquid inlet channel 51, in the embodiment, the liquid discharging one-way valve 44 and the liquid sucking one-way valve 43 are both constructed by adopting one-way valves, and the specific structure refers to the design of the existing product; in order to facilitate the arrangement of the two check valves, in the present embodiment, the two check valves are uniformly arranged on the passage inside the large-diameter plunger 5.

In order to better construct the layout structure of the large and small diameter chambers and save pump body construction material, in this embodiment, the pump body 2 specifically includes a small diameter cavity 7 for enclosing the small diameter chamber 70, and a large diameter cavity 29 for enclosing the large diameter chamber 20. In order to facilitate the connection of the two cavity structures, the upper end opening part of the large-diameter cavity 20 is set to be an open structure; the small-diameter cavity 7 is butted with the large-diameter cavity 29, so that the large-diameter cavity 20 is communicated with the small-diameter cavity 70, in this embodiment, specifically, the lower port of the small-diameter cavity 7 is liquid-tightly sleeved in the upper port of the large-diameter cavity 20, that is, the small-diameter cavity is connected by using a sleeving structure, which is convenient for manufacturing and sealing. The specific structure of the pump body 2 may be arranged in an upper and lower equal-size structure, or may be constructed in an integral structure without adopting the segmented splicing structure.

As described above, in the present embodiment, the pump body 2 is configured in the cylindrical structure, and the small-diameter chamber 70, the large-diameter chamber 20, and the plunger 3 are configured in the cylindrical structure.

As shown in fig. 7, in order to facilitate the manufacture of the small-diameter chamber 7, in the present embodiment, the small-diameter chamber 70 is arranged to include a housing chamber portion 702 and a lower end mouth portion which is a plunger hole structure 701, and the housing chamber portion 702 is located on an adjacent upper side of the plunger hole structure 701; on a plane perpendicular to the vertical direction, the projections of the cavity walls of the accommodating cavity part 702 are all positioned outside the projection of the plunger hole structure 702 and have a difference of more than a preset distance, namely, in the process that the small-diameter plunger 6 moves upwards, the distance between the small-diameter plunger 6 and the inner wall surface of the accommodating cavity part 702 is greater than the distance between the small-diameter plunger and the inner wall of the plunger hole structure 702, so that part of solution medium can be stored; specifically, the accommodation chamber part 702 is located in the plunger hole structure 701, and both are cylindrical chamber structures, and the central axes of the two are arranged in a collinear manner, and the radius of the accommodation chamber part 702 is larger than that of the plunger hole structure 701.

Based on the structure shown in fig. 3 to 8, the working process of the reciprocating plunger pump is as follows:

(1) As shown in fig. 7, in the process that the reciprocating drive mechanism drives the plunger 3 to move downwards by the stroke L2 through the transmission rod 11, the liquid discharge check valve 44 is opened to open the liquid discharge channel 8 and the liquid suction check valve 43 is closed to close the liquid inlet channel 51 due to the pressure of the solution medium such as crude oil, and in the process, the small diameter plunger portion 6 exits from a part of the small diameter chamber 70 and the large diameter plunger portion 5 occupies a part of the transfer chamber 202, so that the solution medium such as crude oil sealed in the transfer chamber 202 is pressed into the liquid discharge cavity from the transfer chamber 202, namely into the empty small diameter chamber 70, and the volume of the solution medium entering the liquid discharge cavity is larger than the added volume of the liquid discharge cavity due to the exit of the small diameter plunger portion 6 because the outer diameter of the small diameter plunger portion 6 is larger than the outer diameter of the transmission rod 11, so that a part of the solution medium is discharged from the liquid discharge hole 71, and the solution medium is discharged from the liquid discharge hole 71 in the downward movement stroke of the plunger.

(2) As shown in fig. 8, during the stroke of the reciprocating driving mechanism driving the plunger 3 to move up by L2 through the transmission rod 11, the check of the check valve 44 for liquid discharge closes the liquid discharge passage 8 due to the pressure of the solution medium such as crude oil, so that negative pressure is generated in the intermediate chamber portion 202 to open the check valve 43 for liquid suction, so as to open the liquid inlet passage 51, and thus the solution medium such as petroleum is sucked into the intermediate chamber portion 202; at the same time, the small-diameter plunger portion 6 occupies a part of the small-diameter chamber 70, and the solution medium is discharged from the drain hole 71, so that the solution medium is discharged from the drain hole 71 during the upward stroke of the plunger.

It can be seen from the above description of the working process that, in the use process, the solution medium is discharged from the liquid discharge hole 71 in both the upward and downward strokes of the plunger 3, that is, the embodiment realizes the double-row function based on single-cylinder single suction, so that the improvement of the power balance of the driving device can be effectively realized, and the layout of the submerged type back driving can be better realized.

Preferably, in order to achieve substantially equal liquid discharge flow rates throughout the entire process, i.e., substantially double uniform discharge effect, in the present embodiment, the plunger 3 and the transmission rod 11 are configured and dimensioned such that the ratio of the liquid suction volume to the liquid discharge volume is 1.9 to 2.1, preferably 2, during the upward movement of the plunger 3 relative to the pump body 2 by a unit pitch; wherein the pipetting volume is configured to aspirate the volume of solution medium inside the transfer chamber section 202 during the process, and the drain volume is the volume of solution medium drained from the small diameter chamber 70 during this upward movement.

In order to achieve the above-mentioned substantially double row effect, in the present embodiment, for the cylindrical plunger 3 and the plunger chamber 20, the structural dimensions of the plunger 3 and the transmission rod 11 may be configured to satisfy a ratio of the first value to the second value of 1.95 to 2.05; wherein the first value is configured as the square of the radius of the large diameter plunger 5 and the square of the radius of the transmission rod 11, and the second value is configured as the square of the radius of the small diameter plunger 6, where the radii are the outer diameters.

According to the above description, in the working process, the driving motor of the reciprocating driving mechanism always belongs to the working state, so that the power of the driving motor is smaller than that of the oil well pump with the unidirectional action in one stroke, and as the ratio of the liquid suction volume to the liquid discharge volume is approximately close to 2, the power of the driving motor of the reciprocating driving mechanism is approximately half of that of the oil well pump with the unidirectional action, so that the requirement on equipment can be effectively reduced.

Claims (10)

1. A submerged type reverse-driven single-cylinder single-suction double-row reciprocating plunger pump comprises a pump body provided with a plunger cavity, a reciprocating driving mechanism and a plunger which can be vertically movably arranged in the plunger cavity; the reciprocating driving mechanism is positioned at the lower side of the pump body and drives the plunger to reciprocate based on the transmission rod; the transmission rod passes through a through hole arranged on the pump body in a liquid-tight manner; from bottom to top, the plunger cavity comprises a large-diameter cavity and a small-diameter cavity forming a liquid discharge cavity; the small-diameter cavity is communicated with the outside through a liquid discharge hole formed in the pump body and comprises a section part in a plunger hole structure; the method is characterized in that:

the plunger comprises a small-diameter plunger part and a large-diameter plunger part which are vertically arranged and fixedly connected, and the outer diameter of the small-diameter plunger part is larger than that of the transmission rod; the small-diameter plunger part is in clearance sealing fit with the plunger hole structure, so that the small-diameter chamber is subjected to liquid seal; the large-diameter plunger part is in clearance sealing fit with the large-diameter cavity, and the movable large-diameter plunger part divides the large-diameter cavity into a liquid inlet cavity part with variable volume and a transfer cavity part from top to bottom; the liquid inlet cavity part is communicated with the outside through a liquid inlet hole arranged on the pump body;

a liquid inlet channel and a lower liquid discharging channel part which are vertically arranged are arranged in the large-diameter plunger part, and an upper liquid discharging channel part is arranged on the small-diameter plunger part; the upper drainage channel is butted with the lower drainage channel to form a drainage channel which is used for communicating the small-diameter chamber with the transfer chamber part; the liquid inlet channel is used for communicating the liquid inlet cavity part with the transfer cavity part; the liquid discharge channel is provided with a one-way valve for liquid discharge, and the liquid inlet channel is provided with a one-way valve for liquid suction.

2. A submerged back-driven single cylinder, single suction, double row reciprocating plunger pump as in claim 1 wherein:

the pump body comprises a small-diameter cavity and a large-diameter cavity, wherein the small-diameter cavity is used for enclosing into the small-diameter cavity, and the large-diameter cavity is used for enclosing into the large-diameter cavity; the upper port part of the large-diameter cavity is of an open structure; the small-diameter cavity is in butt joint with the large-diameter cavity, so that the large-diameter cavity is communicated with the small-diameter cavity.

3. A submerged back-driven single cylinder, single suction, double row reciprocating plunger pump as in claim 2 wherein:

the lower port of the small-diameter cavity is sleeved in the upper port in a liquid-tight manner.

4. A submersible back-driven single cylinder, single suction, double row reciprocating plunger pump according to any of claims 1 to 3, characterized by:

the liquid discharge hole is arranged at the top of the pump body.

5. A submersible back-driven single cylinder, single suction, double row reciprocating plunger pump according to any of claims 1 to 4, wherein:

a plurality of the feed liquor hole is followed the circumference equipartition of pump body.

6. A submerged back-driven single cylinder, single suction, double row reciprocating plunger pump according to any of claims 1 to 5, characterized in that:

the pump body is of a cylindrical structure, and the small-diameter cavity and the large-diameter cavity are both of a circular cavity structure.

7. A submersible back-driven single cylinder, single suction, double row reciprocating plunger pump according to any of claims 1 to 6, wherein:

the small-diameter chamber comprises a containing chamber part, and the containing chamber part is positioned on the adjacent upper side of the plunger hole structure; the lower port part of the small-diameter chamber is of the plunger hole structure;

on a plane perpendicular to the vertical direction, the projections of the cavity walls of the accommodating cavity part are positioned outside the projection of the plunger hole structure, and the difference is more than a preset distance.

8. A submersible back-driven single cylinder, single suction, double row reciprocating plunger pump according to any of claims 1 to 7, wherein:

the ratio of the liquid suction volume to the liquid discharge volume is 1.9 to 2.1 during the upward movement of the plunger relative to the pump body by a unit pitch; the imbibing volume is the volume of the solution medium absorbed into the transfer chamber part in the upward moving process of the plunger; the drain volume is the volume of solution medium drained from the small diameter chamber during upward movement of the plunger.

9. The submersible backdriving single cylinder, single suction, double row reciprocating plunger pump of claim 8, wherein:

the ratio of the liquid intake volume to the liquid discharge volume was 2.

10. A submersible back-driven single cylinder, single suction, double row reciprocating plunger pump according to any of claims 1 to 7, wherein:

the dimensions of the plunger and the transmission rod satisfy a ratio of a first value to a second value of 1.95 to 2.05; the first value is the difference between the square of the radius of the large-diameter plunger and the square of the radius of the transmission rod, and the second value is the square of the radius of the small-diameter plunger.

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