Reciprocating positive displacement pump fluid end for conveying trace super medium

Abstract

The invention discloses a reciprocating displacement pump fluid end for conveying trace super media, which comprises a pump body, a motor arranged on the pump body, a worm connected to the output end of the motor, a turbine rotatably connected to the inside of the pump body, a plunger slidably connected to the pump body, an accommodating cavity, a liquid suction one-way valve and a liquid discharge one-way valve arranged on the pump body, and a lantern ring connected to the pump body, an axial flow channel is arranged in the lantern ring; the pump body is connected with a fan-shaped valve seat, a fan-shaped cavity for heat conduction liquid to flow is formed in the fan-shaped valve seat, an inlet flow channel is formed in one end of the fan-shaped valve seat, an outlet flow channel is formed in the other end of the fan-shaped valve seat, and an electric heating wire for heating the heat conduction liquid is wound around the inlet flow channel. One end of the axial flow channel communicates with the inlet flow channel, and the other end communicates with the outlet flow channel; a swing plate is rotationally connected into the fan-shaped valve seat. A cylinder body is arranged outside the fan-shaped valve seat, a piston is connected into the cylinder body in a sliding mode, and an intercepting plate is connected to the piston. The reciprocating type displacement pump fluid end for conveying the trace super-temporary medium is suitable for low-temperature occasions, the phase state of the medium is constant, and conveying is more stable.

Description

Technical Field

[0001] The invention relates to the field of pumps, in particular to a hydraulic end of a reciprocating positive displacement pump for conveying a trace amount of supercritical medium. Background Art

[0002] A positive displacement pump is a pump that transports liquids by changing the volume inside the pump body. It can be used to transport a variety of fluids and is widely used in the fields of petrochemicals, pharmaceuticals, food, nuclear technology, etc. A positive displacement pump consists of a power end and a hydraulic end. The power end provides power input, and the hydraulic end performs the work of conveying the medium. The power end drives the transmission mechanism through a motor to achieve the reciprocating motion of the plunger, and the reciprocating motion of the plunger achieves the suction and discharge of liquid by the hydraulic end. In the prior art, the working stability of the positive displacement pump is poor in low temperature environments. For example, in the outdoor environment in winter, when the temperature is more than ten degrees below zero, the transmission efficiency of the internal transmission mechanism of the positive displacement pump will be affected, which will lead to the inability to absorb and discharge the medium normally. In other words, the working stability of the positive displacement pump in the prior art is not high enough in low temperature environments, which affects the medium transportation. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the existing technical defects: the problem that the medium cannot be stably transported after the phase state is changed by the natural environment, and to provide a reciprocating positive displacement pump hydraulic end that ensures the transportation of trace supercritical media with a constant phase state in a non-liquid and / or liquid fluid medium.

[0004] The technical solution of the present invention is to provide a hydraulic end of a reciprocating positive displacement pump for conveying a trace amount of supercritical medium with the following structure: comprising a pump body, a motor is arranged on the pump body, a worm is connected to the output end of the motor, a turbine is rotatably connected to the pump body for meshing with the worm, a plunger is slidably connected to the pump body, a containing chamber for the flow of the medium is arranged on the pump body, one end of the plunger is rotatably connected to the turbine, and the other end is connected to the containing chamber, a suction check valve and a discharge check valve for communicating with the containing chamber are arranged on the pump body, a sleeve is connected to the pump body, an axial flow channel for the flow of heat transfer fluid is arranged in the sleeve; the pump body is connected to a fan-shaped valve seat, a fan-shaped chamber for the flow of heat transfer fluid is arranged in the fan-shaped valve seat, an inlet flow channel is arranged at one end of the fan-shaped valve seat, and an outlet flow channel is arranged at the other end, an electric motor for heating the heat transfer fluid is wound around the inlet flow channel, and a pressure relief valve is arranged at the pump body. Hot wire; one end of the axial flow channel is connected to the inlet flow channel, and the other end is connected to the outlet flow channel; a swing plate is rotatably connected inside the fan-shaped valve seat, the swing plate divides the fan-shaped chamber into a left half chamber and a right half chamber, a transition flow channel for connecting the left half chamber and the right half chamber is provided on the swing plate, and a pressure plate for opening or closing the transition flow channel is rotatably connected to the swing plate; a power component for driving the swing plate to reciprocate inside the fan-shaped valve seat is provided on the fan-shaped valve seat, a cylinder body is provided outside the fan-shaped valve seat, a piston is slidably connected inside the cylinder body, and a shut-off plate for opening and closing the inlet flow channel is connected to the piston; the left half chamber and the right half chamber on the fan-shaped valve seat are respectively provided with a first airbag and a second airbag for contacting or disengaging with the swing plate, the first airbag is connected to one end of the cylinder body through a first connecting pipe, and the second airbag is connected to the other end of the cylinder body through a second connecting pipe.

[0005] As a preferred embodiment of the present invention, the ring is a circular ring structure, which is composed of a first arc plate and a second arc plate, the first arc plate and the second arc plate are rotatably connected by a rotating shaft, the first arc plate is provided with a first protrusion, and the second arc plate is provided with a second protrusion; when the first arc plate and the second arc plate are closed, the first arc plate and the second arc plate form a closed circular ring structure, the axis of the first arc plate coincides with the axis of the second arc plate, and the first protrusion and the second protrusion are fixedly connected by bolts.

[0006] As a preferred embodiment of the present invention, there are multiple axial flow channels, which are evenly distributed on the first arc plate and the second arc plate around the circumferential direction of the ring, and are arranged on the first arc plate and the second arc plate along the axial direction of the ring.

[0007] As an improvement of the present invention, the pressure plate is located at the port position of the transition channel on the swing plate, and the pressure plate is rotatably connected to the swing plate through a first hinge point. The pressure plate is located on the side of the swing plate facing the outlet channel, and a tension spring is provided between the pressure plate and the swing plate for pulling the pressure plate against the swing plate. One end of the tension spring is rotatably connected to the pressure plate, and the other end is rotatably connected to the swing plate.

[0008] As an improvement of the present invention, the fan-shaped valve seat is rotatably connected to a connecting rod via a second hinge point, a motor for driving the connecting rod to rotate is provided on the fan-shaped valve seat, a radial slide groove is provided along the length direction of the swing plate, a slider is slidably connected in the radial slide groove, the connecting rod and the slider are rotatably connected via a third hinge point, and the distance from the second hinge point to the third hinge point is greater than zero.

[0009] As an improvement of the present invention, the swing plate is rotatably connected to the fan-shaped valve seat via a fourth hinge point, the fan-shaped valve seat is a symmetrical structure, and the second hinge point and the fourth hinge point are located on the symmetry axis of the fan-shaped valve seat.

[0010] As an improvement of the present invention, the end of the fan-shaped valve seat away from the fourth hinge point is an arc bottom, and the end of the swing plate away from the fourth hinge point is an arc distal end portion matching the inner wall of the arc bottom; the end of the fan-shaped valve seat close to the fourth hinge point is an arc head, and the end of the swing plate close to the fourth hinge point is an arc proximal end portion matching the inner wall of the arc head.

[0011] As an improvement of the present invention, the first air bag is located on the inner wall of the fan-shaped valve seat close to the outlet flow channel, one end of the first connecting tube is connected to the first air bag, and the other end is connected to the input end of the cylinder body; the second air bag is located on the inner wall of the fan-shaped valve seat close to the inlet flow channel, one end of the second connecting tube is connected to the second air bag, and the other end is connected to the output end on the cylinder body, and the inlet flow channel is provided with a through hole for the shut-off plate to pass through.

[0012] As an improvement of the present invention, a liquid storage tank is provided between the axial flow channel and the inlet flow channel, the inlet flow channel is communicated with the liquid storage tank, and the output end of the axial flow channel is communicated with the liquid storage tank.

[0013] After adopting the above structure, compared with the prior art, the hydraulic end of a reciprocating positive displacement pump for conveying trace supercritical media of the present invention drives the worm to rotate by a motor, and the worm and the turbine are transmitted to drive the reciprocating motion of the plunger, so as to realize that the medium flows from the liquid inlet check valve through the accommodating chamber and is discharged from the liquid discharge check valve; and, through the reciprocating swing plate in the fan-shaped valve seat, the heat-conducting liquid in the fan-shaped valve seat can be discharged to the axial flow channel area in the sleeve ring, and the electric heating wire of the inlet flow channel can heat the heat-conducting liquid flowing through this area, so that the temperature of the heat-conducting liquid discharged to the axial flow channel increases, that is, the temperature of the pump body is increased by the temperature of the heat-conducting liquid in the sleeve ring, so as to ensure the internal The transmission of the components works effectively to prevent the positive displacement pump from not being able to work properly in a low-temperature environment; wherein, through the transmission of the connecting rod, the slider, the pendulum plate and the radial grooves on the pendulum plate, the heat transfer liquid can be slowly sucked into the right half-chamber area, and then the heat transfer liquid in the right half-chamber can be quickly discharged to the left half-chamber through the transition channel, so as to ensure that the heat transfer liquid sucked into the fan-shaped valve seat gets enough heating time for the heating wire; and the inlet channel can be closed by the first airbag, the second airbag, the cylinder body, the piston, and the intercepting plate to ensure that the heat transfer liquid in the right half-chamber is effectively discharged to the left half-chamber, and it can also prevent the heat transfer liquid in the right half-chamber from being pushed back into the liquid storage tank when the pendulum plate is reversed. In summary, the present invention provides a reciprocating positive displacement pump hydraulic end for conveying a trace amount of supercritical medium that is suitable for low-temperature occasions and has more stable medium conveying. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The present invention is a schematic structural diagram of the hydraulic end of a reciprocating positive displacement pump for transporting trace amounts of supercritical media.

[0015] Figure 2 It is a structural schematic diagram of the fan-shaped valve seat in the present invention.

[0016] Figure 3 It is a schematic diagram of the structure of the sleeve ring in the present invention.

[0017] As shown in the figure: 1. Pump body, 2. Motor, 3. Worm, 4. Turbine, 5. Plunger, 6. Accommodating chamber, 7. Suction check valve, 8. Discharge check valve, 9. Ring, 10. Axial flow channel, 11. Fan-shaped valve seat, 12. Third hinge point, 13. Inlet flow channel, 14. Outlet flow channel, 15. Heating wire, 16. Swing plate, 17. Left half chamber, 18. Right half chamber, 19. Transition flow channel, 20. Cylinder body, 21. Piston, 22, shutoff plate, 23, first air bag, 24, second air bag, 25, first arc plate, 26, second arc plate, 27, rotating shaft, 28, first protrusion, 29, second protrusion, 30, pressure plate, 31, first hinge point, 32, tension spring, 33, second hinge point, 34, connecting rod, 35, radial slide groove, 36, slider, 37, fourth hinge point, 38, first connecting pipe, 39, second connecting pipe. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0019] As shown in the figure, the hydraulic end of a reciprocating positive displacement pump for conveying a trace supercritical medium of the present invention comprises a pump body 1, a motor 2 is provided on the pump body 1, a worm 3 is connected to the output end of the motor 2, a turbine 4 for meshing with the worm 3 is rotatably connected in the pump body 1, a plunger 5 is slidably connected to the pump body 1, a containing chamber 6 for medium flow is provided on the pump body 1, one end of the plunger 5 is rotatably connected to the turbine 4, and the other end is connected to the containing chamber 6; wherein the trace supercritical medium refers to a liquid medium, and the plunger 5 is eccentrically arranged with the turbine 4, that is, the rotating axis of the plunger 5 and the turbine 4 deviates from the rotating axis of the turbine 4 on the pump body 1; the pump body 1 is provided with a suction check valve 7 and a discharge check valve 8 for communicating with the containing chamber 6. Valve 8, a sleeve ring 9 is connected to the pump body 1, and the sleeve ring 9 is sleeved on the area of ​​the pump body 1 close to the plunger 5, and an axial flow channel 10 for the flow of heat-conducting fluid is provided in the sleeve ring 9; the pump body 1 is connected to a fan-shaped valve seat 11, and a fan-shaped chamber for the flow of heat-conducting fluid is provided in the fan-shaped valve seat 11, and the heat-conducting fluid used here is water or heat-conducting oil; the fan-shaped valve seat 11 has a structure that is small at the top and large at the bottom, and the side wall angles on both sides of the fan-shaped valve seat 11 are acute angles, and the acute angle is greater than 30°; an inlet flow channel 13 is provided at one end of the fan-shaped valve seat 11, and an outlet flow channel 14 is provided at the other end, and an electric heating wire 15 for heating the heat-conducting fluid is wound around the inlet flow channel 13, and the outer wall of the outlet flow channel 14 can also be wound with the electric heating wire 15; axial One end of the flow channel 10 is connected to the inlet flow channel 13, and the other end is connected to the outlet flow channel 14; a swing plate 16 is rotatably connected in the fan-shaped valve seat 11, and the swing plate 16 divides the fan-shaped chamber into a left half chamber 17 and a right half chamber 18; the area between the swing plate 16 and the outlet flow channel 14 is defined as the left half chamber 17, and the area between the swing plate 16 and the inlet flow channel 13 is defined as the right half chamber 18. As the angle of rotation of the swing plate 16 in the fan-shaped valve seat 11 changes, the space size of the left half chamber 17 and the right half chamber 18 will change; a transition flow channel 19 for connecting the left half chamber 17 and the right half chamber 18 is provided on the swing plate 16, and a pressure switch for opening or closing the transition flow channel 19 is rotatably connected on the swing plate 16. Plate 30; the fan-shaped valve seat 11 is provided with a power assembly for driving the swing plate 16 to reciprocate inside the fan-shaped valve seat 11, and a cylinder body 20 is provided outside the fan-shaped valve seat 11, and a piston 21 is slidably connected inside the cylinder body 20, and a shut-off plate 22 for opening and closing the inlet flow channel 13 is connected to the piston 21; the left half chamber 17 and the right half chamber 18 on the fan-shaped valve seat 11 are respectively provided with a first air bag 23 and a second air bag 24 for contacting or disengaging with the swing plate 16, and the first air bag 23 and the second air bag 24 are respectively located on both sides of the swing plate 16, and the first air bag 23 is connected to one end of the cylinder body 20 through a first connecting pipe, and the second air bag 24 is connected to the other end of the cylinder body 20 through a second connecting pipe.

[0020] The collar 9 is a circular ring structure, which is composed of a first circular arc plate 25 and a second circular arc plate 26. The first circular arc plate 25 and the second circular arc plate 26 refer to plate structures with circular arc structures. The first circular arc plate 25 and the second circular arc plate 26 are rotatably connected by a rotating shaft 27. A first protrusion 28 is provided on the first circular arc plate 25, and a second protrusion is provided on the second circular arc plate 26. When the first circular arc plate 25 and the second circular arc plate 26 are closed, the first circular arc plate 25 and the second circular arc plate 26 form a closed circular ring structure, the axis of the first circular arc plate 25 coincides with the axis of the second circular arc plate 26, and the first protrusion 28 and the second protrusion 29 are fixedly connected by bolts, and the first protrusion 28 and the second protrusion 29 are both provided with mounting holes for the bolts to pass through. The split structure of the collar 9 can facilitate the disassembly and assembly of the collar 9 and the pump body 1, that is, the collar 9 can be removed under non-low temperature conditions.

[0021] There are multiple axial flow channels 10 , which are evenly distributed on the first arc plate 25 and the second arc plate 26 in the circumferential direction of the collar 9 , and are arranged on the first arc plate 25 and the second arc plate 26 along the axial direction of the collar 9 .

[0022] The pressure plate 30 is located at the port position of the transition flow channel 19 on the swing plate 16. The transition flow channel 19 runs through the thickness direction of the swing plate 16. The pressure plate 30 is rotatably connected to the swing plate 16 through the first hinge point 31. The pressure plate 30 is located on the swing plate 16 facing the outlet flow channel 14. A tension spring 32 is provided between the pressure plate 30 and the swing plate 16 for pulling the pressure plate 30 against the swing plate 16. One end of the tension spring 32 is rotatably connected to the pressure plate 30, and the other end is rotatably connected to the swing plate 16. Here, when the swing plate 16 rotates clockwise, that is, the process of the fan-shaped valve seat 11 sucking the heat transfer fluid, the pressure plate 30 is against the swing plate 16, and the transition flow channel 19 is in a closed state; when the swing plate 16 rotates counterclockwise, the swing plate 16 is subjected to the thrust of the heat transfer fluid in the right half chamber 18 and overcomes the constraint of the tension spring 32 and is separated from the end face of the swing plate 16, and the transition flow channel 19 is in an open state.

[0023] The power assembly means that the fan-shaped valve seat 11 is rotatably connected to the connecting rod 34 through the second hinge point 33, the fan-shaped valve seat 11 is provided with a motor for driving the connecting rod 34 to rotate, the swing plate 16 is provided with a radial slot 35 along the length direction, and a slider 36 is slidably connected in the radial slot 35, the connecting rod 34 and the slider 36 are rotatably connected through the third hinge point 12, and the distance from the second hinge point 33 to the third hinge point 12 is greater than zero. Here, the motor drives the connecting rod 34 to rotate clockwise, and the connecting rod 34 can drive the swing plate 16 to rotate clockwise and counterclockwise in the fan-shaped valve seat 11 through the slider 36 and the radial slot 35; in the process of one rotation of the connecting rod 34, the swing plate 16 completes one clockwise rotation and one counterclockwise rotation, and the clockwise rotation time of the swing plate 16 is longer than the counterclockwise rotation time of the swing plate 16; wherein, when the swing plate 16 rotates clockwise, the inlet on the fan-shaped valve seat 11 The mouth flow channel 13 sucks the heat-conducting liquid from the liquid storage tank into the right half chamber 18. Since the swing plate 16 rotates clockwise more slowly than counterclockwise, the sucked heat-conducting liquid can be fully heated by the heating wire; and the swing plate 16 rotates counterclockwise faster, so the heated heat-conducting liquid in the right half chamber 18 can be quickly discharged into the left half chamber 17; through the action of slow suction and fast discharge, the body fluid sucked into the fan-shaped valve seat 11 can be fully heated, and the amount of heat-conducting liquid discharged from the fan-shaped valve seat 11 can be kept constant.

[0024] The swing plate 16 is rotatably connected to the fan-shaped valve seat 11 via the fourth hinge point 37. The fan-shaped valve seat 11 is a symmetrical structure, and the second hinge point 33 and the fourth hinge point 37 are located on the symmetry axis of the fan-shaped valve seat 11, that is, the fan-shaped valve seat 11 is a left-right symmetrical structure.

[0025] The end of the fan-shaped valve seat 11 away from the fourth hinge point 37 is the bottom of the arc, the distance from the second hinge point 33 to the third hinge point 12 is smaller than the distance from the second hinge point 33 to the fourth hinge point 37, and the end of the swing plate 16 away from the fourth hinge point 37 is the arc-shaped distal end portion matching the inner wall of the bottom of the arc, thereby reducing the gap between the bottom of the swing plate 16 and the inner wall of the bottom of the fan-shaped valve seat 11; that is, the outer wall diameter value of the arc-shaped distal end portion at the lower end of the swing plate 16 is equal to the inner wall diameter value of the arc bottom of the fan-shaped valve seat 11; the end of the fan-shaped valve seat 11 close to the fourth hinge point 37 is the arc-shaped head, and the end of the swing plate 16 close to the fourth hinge point 37 is the arc-shaped proximal end portion matching the inner wall of the arc head, thereby reducing the gap between the head of the swing plate 16 and the inner wall of the head of the fan-shaped valve seat 11; that is, the outer wall diameter value of the arc-shaped proximal end portion at the upper end of the swing plate 16 is equal to the inner wall diameter value of the arc head of the fan-shaped valve seat 11. Here, the lower part of the fan-shaped valve seat 11 is defined as the bottom of the fan-shaped valve seat 11 , and the upper area of ​​the fan-shaped valve seat 11 is defined as the head of the fan-shaped valve seat 11 .

[0026] The first air bag 23 is located on the inner wall of the fan-shaped valve seat 11 close to the outlet flow channel 14, one end of the first connecting pipe 38 is connected to the first air bag 23, and the other end is connected to the input end of the cylinder body 20; the second air bag 24 is located on the inner wall of the fan-shaped valve seat 11 close to the inlet flow channel 13, one end of the second connecting pipe 39 is connected to the second air bag 24, and the other end is connected to the output end on the cylinder body 20, and the inlet flow channel 13 is provided with a through hole for the shut-off plate 22 to pass through. Here, when the swing plate 16 rotates clockwise to the left limit position and abuts against the first airbag 23, the gas in the first airbag 23 will flow through the first connecting pipe 38 into the input end of the cylinder body 20, and the first airbag 23 will be flattened, thereby pushing the piston 21 to slide in the cylinder body 20. The sliding of the piston 21 will blow the second airbag 24 to bulge, and the sliding of the piston 21 will drive the intercepting plate 22 to slide to close the inlet flow channel 13; next, when the connecting rod 34 drives the swing plate 16 to reverse and rotate counterclockwise, the inlet flow channel 13 is in a closed state, and the pressure plate 30 rotates to open the transition flow channel 1 9, then the heat transfer fluid in the right half chamber 18 will flow through the transition channel 19 and quickly enter the left half chamber 17; when the swing plate 16 rotates counterclockwise to the right extreme position, the swing plate 16 will abut against the second airbag 24, and the gas in the second airbag 24 will flow through the second connecting pipe 39 and enter the cylinder body 20, the second airbag 24 will be flattened, and the piston 21 will slide in the cylinder body 20, and the piston 21 will drive the intercepted gas to be pulled out from the inlet channel 13, and the inlet channel 13 is in a connected state, and the reverse sliding of the piston 21 will discharge the gas in the cylinder body 20 to the first airbag 23, and the first airbag 23 will be blown up.

[0027] A liquid storage tank is provided between the axial flow channel 10 and the inlet flow channel 13, the inlet flow channel 13 is connected to the liquid storage tank, and the output end of the axial flow channel 10 is connected to the liquid storage tank. The input end of the axial flow channel 10 is connected to the outlet flow channel 14 on the fan-shaped valve seat 11 through a metal hose, the output end of the axial flow channel 10 is connected to the liquid storage tank through a metal hose, and the inlet flow channel 13 on the fan-shaped valve seat 11 is connected to the liquid storage tank through a metal hose. The heat transfer fluid flows from the liquid storage tank to the inlet flow channel 13, flows through the right half chamber 18, the transition flow channel 19, the left half chamber 17, the outlet flow channel 14, the axial flow channel 10 in sequence, and finally flows back to the liquid storage tank. The pump body 1 can be heated during the process of the heat transfer fluid flowing through the axial flow channel 10, that is, the heat of the heat transfer fluid is transferred to the structure inside the pump body.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement and improvement made within the claims of the present invention shall be included in the protection scope of the present invention.

Claims

1. A reciprocating positive displacement pump hydraulic end for conveying micro-critical medium, comprising a pump body, a motor is provided on the pump body, a worm is connected to the output end of the motor, a turbine for meshing with the worm is rotatably connected in the pump body, a plunger is slidably connected to the pump body, a receiving chamber for medium flow is provided on the pump body, one end of the plunger is rotatably connected to the turbine, and the other end is connected to the receiving chamber, a suction check valve and a discharge check valve for communicating with the receiving chamber are provided on the pump body, and the characteristics are: The pump body is connected with a collar, and an axial flow channel for the flow of heat transfer fluid is arranged inside the collar; the pump body is connected with a fan-shaped valve seat, and a fan-shaped chamber for the flow of heat transfer fluid is arranged inside the fan-shaped valve seat, an inlet flow channel is arranged at one end of the fan-shaped valve seat, and an outlet flow channel is arranged at the other end, and an electric heating wire for heating the heat transfer fluid is wound around the inlet flow channel; one end of the axial flow channel is connected with the inlet flow channel, and the other end is connected with the outlet flow channel; a swing plate is rotatably connected inside the fan-shaped valve seat, and the swing plate divides the fan-shaped chamber into a left half chamber and a right half chamber, and a transition flow channel for connecting the left half chamber and the right half chamber is arranged on the swing plate A pressure plate for opening or closing the transition flow channel is rotatably connected to the swing plate; a power assembly for driving the swing plate to reciprocate inside the fan-shaped valve seat is provided on the fan-shaped valve seat, a cylinder body is provided outside the fan-shaped valve seat, a piston is slidably connected inside the cylinder body, and a shut-off plate for opening and closing the inlet flow channel is connected to the piston; the left half chamber and the right half chamber on the fan-shaped valve seat are respectively provided with a first airbag and a second airbag for contacting or disengaging with the swing plate, the first airbag is connected to one end of the cylinder body through a first connecting pipe, and the second airbag is connected to the other end of the cylinder body through a second connecting pipe.

2. The hydraulic end of a reciprocating positive displacement pump for transporting micro-amounts of supercritical media according to claim 1, characterized in that: The collar is a circular ring structure, which is composed of a first circular arc plate and a second circular arc plate. The first circular arc plate and the second circular arc plate are rotatably connected via a rotating shaft. The first circular arc plate is provided with a first protrusion, and the second circular arc plate is provided with a second protrusion. When the first circular arc plate and the second circular arc plate are closed, the first circular arc plate and the second circular arc plate form a closed circular ring structure, the axis of the first circular arc plate coincides with the axis of the second circular arc plate, and the first protrusion and the second protrusion are fixedly connected by bolts.

3. The hydraulic end of a reciprocating positive displacement pump for transporting micro-amounts of supercritical media according to claim 2, characterized in that: There are multiple axial flow channels, which are evenly distributed on the first arc plate and the second arc plate around the circumferential direction of the collar, and are arranged on the first arc plate and the second arc plate along the axial direction of the collar.

4. The hydraulic end of a reciprocating positive displacement pump for transporting micro-amounts of supercritical media according to claim 1, characterized in that: The pressure plate is located at the port position of the transition flow channel on the swing plate. The pressure plate is rotatably connected to the swing plate through the first hinge point. The pressure plate is located on the side of the swing plate facing the outlet flow channel. A tension spring is provided between the pressure plate and the swing plate to pull the pressure plate against the swing plate. One end of the tension spring is rotatably connected to the pressure plate, and the other end is rotatably connected to the swing plate.

5. The hydraulic end of a reciprocating positive displacement pump for transporting micro-amounts of supercritical media according to claim 1, characterized in that: The fan-shaped valve seat is rotatably connected to a connecting rod via a second hinge point, a motor for driving the connecting rod to rotate is provided on the fan-shaped valve seat, a radial slide groove is provided along the length direction of the swing plate, a slider is slidably connected in the radial slide groove, the connecting rod and the slider are rotatably connected via a third hinge point, and a distance from the second hinge point to the third hinge point is greater than zero.

6. The hydraulic end of a reciprocating positive displacement pump for transporting micro-amounts of supercritical media according to claim 5, characterized in that: The swing plate is rotatably connected to the fan-shaped valve seat through the fourth hinge point. The fan-shaped valve seat is a symmetrical structure, and the second hinge point and the fourth hinge point are located on the symmetry axis of the fan-shaped valve seat.

7. The hydraulic end of a reciprocating positive displacement pump for transporting micro-amounts of supercritical media according to claim 6, characterized in that: The end of the fan-shaped valve seat away from the fourth hinge point is the arc bottom, and the end of the swing plate away from the fourth hinge point is the arc distal end matching the inner wall of the arc bottom; the end of the fan-shaped valve seat close to the fourth hinge point is the arc head, and the end of the swing plate close to the fourth hinge point is the arc proximal end matching the inner wall of the arc head.

8. The hydraulic end of a reciprocating positive displacement pump for transporting micro-amounts of supercritical media according to claim 1, characterized in that: The first airbag is located on the inner wall of the fan-shaped valve seat close to the outlet flow channel, one end of the first connecting tube is connected to the first airbag, and the other end is connected to the input end of the cylinder body; the second airbag is located on the inner wall of the fan-shaped valve seat close to the inlet flow channel, one end of the second connecting tube is connected to the second airbag, and the other end is connected to the output end on the cylinder body, and a through hole is provided on the inlet flow channel for the intercepting plate to pass through.

9. The hydraulic end of a reciprocating positive displacement pump for transporting micro-amounts of supercritical media according to claim 1, characterized in that: A liquid storage tank is arranged between the axial flow channel and the inlet flow channel, the inlet flow channel is communicated with the liquid storage tank, and the output end of the axial flow channel is communicated with the liquid storage tank.

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