Liquid self-balancing injection pump

Abstract

The liquid self-balancing injection pump comprises a first pump body, a second pump body, a liquid inlet pipe, a liquid outlet pipe, a waste liquid inlet pipe and a waste liquid outlet pipe, wherein the liquid inlet pipe, the liquid outlet pipe, the waste liquid inlet pipe and the waste liquid outlet pipe are communicated with the first pump body and the second pump body; two pistons which are movably assembled with the inner cavities in a sealing manner and divide the inner cavities into two sealing cavities and sterilization air cavities positioned between the two sealing cavities are arranged in the inner cavities of the first pump body and the second pump body at intervals along the length direction; a linkage rod positioned in the corresponding sterilization air cavity is fixedly connected between the two pistons in the same pump body; a connecting rod penetrating out of the first pump body and the second pump body is arranged on the linkage rod of the first pump body and the linkage rod of the second pump body; the two ends of the first pump body and the two ends of the second pump body are each provided with two connectors communicated with the same sealing cavity, and one-way valves are arranged in the connectors respectively. The liquid balance device can solve the problem of liquid balance of continuous blood purification equipment in a vibration impact environment of a moving occasion, simplifies the principle, and improves the reliability.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, specifically to a self-balancing liquid injection pump. Background Technology

[0002] The accuracy of fluid balance in emergency medical equipment such as continuous blood purification devices is crucial. The market primarily uses the metering method and the balance chamber method.

[0003] The metering method requires the external liquid pump to deliver the liquid, and uses high-precision liquid metering sensors (such as load cells and volumetric sensors) to form a feedback closed-loop control to precisely control the flow rate between the delivery pump and the waste pump. This approach heavily relies on the accuracy of the liquid metering sensors. When there are environmental factors such as vibration and shock, the accuracy of the liquid metering sensors cannot be guaranteed, so the equipment cannot be used in mobile applications.

[0004] The basic principle of the balanced cavity method is as follows: Figure 1 As shown, two linked pistons 2 are placed in the same cavity, with a fixed partition between them, forming four closed cavities: cavity Y1, cavity Y2, cavity Z1, and cavity Z2. Each cavity has the same cross-sectional area, so the volume change of the four cavities is the same when pistons 2 move. When liquid is pumped into cavity Y1 by an external pump, waste liquid is discharged from the body in cavity Z1, liquid is input into the body in cavity Y2, and liquid is discharged into the waste liquid bag in cavity Z2. When liquid is pumped into cavity Y2, waste liquid is discharged from the body in cavity Z2, liquid is input into the body in cavity Y1, and liquid is discharged into the waste liquid bag in cavity Z1. The direction of liquid flow is controlled by the external pump and an electromagnetic on / off valve. The main disadvantage of this method is the complex structure of the balancing cavity, the complex liquid circuit due to the need for an external pump and an electromagnetic on / off valve, and low reliability. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a self-balancing liquid injection pump to solve the problem of liquid balance in continuous blood purification equipment under vibration and shock environment in mobile settings, while simplifying the principle and improving reliability.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows.

[0007] A self-balancing liquid injection pump includes a first pump body and a second pump body with identical structures arranged vertically, a liquid inlet pipe, a liquid outlet pipe, a waste liquid inlet pipe, and a waste liquid outlet pipe. Each of the first and second pump bodies has two pistons spaced along its length, which are movably and sealingly assembled with the inner cavity and divide the inner cavity into two sealed chambers and a sterilization gas chamber located between the two sealed chambers. A linkage rod located in the corresponding sterilization gas chamber and used to achieve linkage between the two pistons is fixedly connected between the two pistons in the same pump body. A connecting rod extending from the first and second pump bodies and used to drive the four pistons in linkage is provided on the linkage rod of the first and second pump bodies.

[0008] The first pump body has two sealed cavities, a first sealed cavity and a second sealed cavity arranged left and right respectively. The left end of the first pump body has a first interface and a second interface that communicate with the first sealed cavity respectively, and the right end of the first pump body has a third interface and a fourth interface that communicate with the second sealed cavity respectively. The second pump body has two sealed cavities, a fourth sealed cavity and a third sealed cavity arranged left and right respectively. The right end of the second pump body has a fifth interface and a sixth interface that communicate with the third sealed cavity respectively, and the left end of the second pump body has a seventh interface and an eighth interface that communicate with the fourth sealed cavity respectively. The first interface and the fifth interface are both connected to the liquid inlet pipe, the second interface and the sixth interface are both connected to the liquid outlet pipe, the third interface and the seventh interface are both connected to the waste liquid inlet pipe, and the fourth interface and the eighth interface are both connected to the waste liquid outlet pipe.

[0009] The first interface is equipped with an A1 side inlet check valve, the second interface is equipped with an A1 side outlet check valve, the third interface is equipped with a B1 side inlet check valve, the fourth interface is equipped with a B1 side outlet check valve, the fifth interface is equipped with an A2 side inlet check valve, the sixth interface is equipped with an A2 side outlet check valve, the seventh interface is equipped with a B2 side inlet check valve, and the eighth interface is equipped with a B2 side outlet check valve.

[0010] Preferably, the sterilization air chambers of the first pump body and the second pump body are respectively provided with mounting seats fixedly sleeved in the middle of the corresponding linkage rod and perpendicular to the linkage rod; the linkage rod is Y-shaped, and the two inner ends of the linkage rod are respectively connected to the two mounting seats one-to-one through the slot structure, and the outer end of the linkage rod away from the two inner ends passes through the first pump body and the second pump body.

[0011] Preferably, the outer end of the connecting rod is connected to an electric cylinder for driving the connecting rod to move in order to drive the piston in conjunction with the connecting rod.

[0012] Preferably, the first pump body and the second pump body are respectively provided with openings for avoiding the connecting rod when the connecting rod moves; the first pump body and the second pump body are respectively provided with flexible tubes symmetrically arranged on both sides of the corresponding mounting base and connected to the corresponding mounting base and the inner cavity to block the corresponding openings to ensure the sealing of the corresponding sterilization air chamber and to divide the corresponding sterilization air chamber into the first sterilization air chamber and the second sterilization air chamber.

[0013] Preferably, the linkage rod is provided with an air passage for connecting the first sterilization air chamber and the second sterilization air chamber corresponding to it to ensure the air pressure balance between the first sterilization air chamber and the second sterilization air chamber.

[0014] Due to the adoption of the above technical solutions, the technological progress achieved by this utility model is as follows.

[0015] This invention, through the design of a first pump body, a second pump body, a piston, a linkage rod, a connecting rod, and a one-way valve, not only achieves automatic liquid balance, making liquid balance control independent of high-precision sensors such as liquid flow meters, but also exhibits good tolerance to vibration and shock environments, ensuring high-precision liquid balance control even under vibration and shock conditions. This makes it suitable for mobile applications, enabling continuous blood purification equipment to be used in mobile emergency settings such as ambulances, significantly improving the treatment effect for some critically ill patients. Furthermore, it integrates liquid balance control and the pump into one unit, using a one-way valve for flow distribution. Compared to the traditional balanced chamber structure, this reduces the number of components, simplifies the structure, and provides higher reliability. Attached Figure Description

[0016] Figure 1 This is a basic schematic diagram of the existing balanced cavity method;

[0017] Figure 2 This is a schematic diagram of the structure of this utility model;

[0018] Figure 3 This is a schematic diagram of one embodiment of the present invention;

[0019] Figure 4 For the present utility model Figure 3 The main view;

[0020] Figure 5 For the present utility model Figure 4 BB view;

[0021] Figure 6 For the present utility model Figure 3 Side view;

[0022] Figure 7 For the present utility model Figure 6 AA view;

[0023] Figure 8For the present utility model Figure 6 CC view;

[0024] Figure 9 For the present utility model Figure 6 DD view;

[0025] Figure 10 For the present utility model Figure 6 EE view.

[0026] Among them: 1a. First pump body, 1b. Second pump body, 2. Piston, 3. Linkage rod, 4. Air passage, 5. Mounting base, 6. Connecting rod, 7. Flexible tube, 8. Sterilization air chamber, 81. First sterilization air chamber, 82. Second sterilization air chamber, 9. Liquid inlet pipe, 10. Liquid outlet pipe, A1. First sealed chamber, B1. Second sealed chamber, A2. Third sealed chamber, B2. Fourth sealed chamber, A1-F1. A1 side liquid inlet check valve, A1-F2. A1 side liquid outlet check valve 11. B1-F1. B1 side inlet check valve, 200. B1 side outlet check valve, 300. A2-F1. A2 side inlet check valve, 400. A2-F2. A2 side outlet check valve, 500. B2-F2. B2 side inlet check valve, 600. B2-F2. B2 side outlet check valve, 700. Waste liquid inlet pipe, 800. Waste liquid outlet pipe, 900. Shell, 100. End cap, 110. Liquid hole, 120. Y1. First cavity, 130. Second cavity, 140. Third cavity, 150. Fourth cavity. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0028] A self-balancing liquid injection pump, combined with Figure 2As shown, the system includes a first pump body 1a, a second pump body 1b, a liquid inlet pipe 9, a liquid outlet pipe 10, a waste liquid inlet pipe 11, and a waste liquid outlet pipe 12. The first pump body 1a and the second pump body 1b are arranged vertically and have the same structure. A piston 2 is provided in the inner cavity of both the first pump body 1a and the second pump body 1b, and the piston 2 and the inner cavity form a structure similar to a syringe. The liquid inlet pipe 9, the liquid outlet pipe 10, the waste liquid inlet pipe 11, and the waste liquid outlet pipe 12 are respectively connected to the first pump body 1a and the second pump body 1b. In use, the movement of piston 2 enables liquid to enter the first pump body 1a and the second pump body 1b through the liquid inlet pipe 9 and to discharge the liquid entering the first pump body 1a and the second pump body 1b through the liquid outlet pipe 10, thereby injecting liquid into the human body; at the same time, waste liquid enters the first pump body 1a and the second pump body 1b through the waste liquid inlet pipe 11 and to discharge the waste liquid entering the first pump body 1a and the second pump body 1b through the waste liquid outlet pipe 12, thereby removing waste liquid from the human body; and can automatically maintain the same amount of liquid injected into the human body and waste liquid removed from the human body, achieving liquid self-balance, and can precisely control the flow rate and volume of liquid injected into the human body and waste liquid removed from the human body by precisely controlling the movement speed and distance of piston 2.

[0029] Each of the first pump body 1a and the second pump body 1b contains two pistons 2 within its inner cavity. The two pistons 2 are spaced apart along the length of the inner cavity and are respectively fitted with movable seals within the inner cavity. The specific structure of these movable seals includes, but is not limited to, rubber pistons, single or multiple rubber rings, or other sealing structures. The two pistons 2 divide the inner cavity into two sealed chambers and a sterilization gas chamber 8, with the sterilization gas chamber 8 located between the two sealed chambers. A linkage rod 3 is fixedly connected between the two pistons 2, located within the sterilization gas chamber 8, and is used to achieve linkage between the two pistons 2. A connecting rod 6 is provided on the linkage rod 3 of the first pump body 1a and the second pump body 1b. The connecting rod 6 extends from the first pump body 1a and the second pump body 1b, and drives the two linkage rods 3 to achieve linkage between the four pistons 2.

[0030] Specifically, each of the sterilization chambers 8 of the first pump body 1a and the second pump body 1b is provided with a mounting seat 5. The mounting seat 5 is fixedly sleeved in the middle of the corresponding linkage rod 3 and is set perpendicular to the linkage rod 3. The connecting rod 6 is Y-shaped, and the two inner ends of the connecting rod 6 are respectively connected to the two mounting seats 5 one-to-one through the slot structure, which can facilitate the connection and separation of the two. The outer end of the connecting rod 6 away from the two inner ends passes through the first pump body 1a and the second pump body 1b and is connected to an electric cylinder. The electric cylinder is used to drive the connecting rod 6 to move, thereby driving the four pistons 2 to move in linkage.

[0031] The first pump body 1a and the second pump body 1b are respectively provided with openings to allow the connecting rod 6 to pass during its movement. To fully ensure the isolation of the liquid from the external atmospheric environment and prevent bacteria, dust, and other objects from mixing into the liquid, two flexible tubes 7 are respectively provided in the first pump body 1a and the second pump body 1b. The two flexible tubes 7 are symmetrically arranged on both sides of the corresponding mounting base 5. The two ends of the flexible tube 7 on each side are connected to the corresponding mounting base 5 and the inner cavity, respectively. This not only ensures the sealing of the corresponding sterilization air chamber 8 by blocking the opening through the flexible tubes 7 and completely isolates the corresponding piston 2 from the external atmospheric environment, but also does not affect the movement of the connecting rod 6. Specifically, the specific structure of the flexible tube 7 includes, but is not limited to, a bellows, a flexible diaphragm, a flexible film, or an elastic film.

[0032] The sterility of the sterilization chamber 8 is mainly achieved through the overall high-temperature sterilization of this invention, or through production in a sterile production workshop. The sterilization chamber 8 is divided into a first sterilization chamber 81 and a second sterilization chamber 82, which are arranged to the left and right, by the corresponding mounting base 5 and flexible tube 7. The linkage rod 3 is provided with an air passage 4, and the two ends of the air passage 4 are respectively connected to the corresponding first sterilization chamber 81 and second sterilization chamber 82, thereby realizing the connection between the first sterilization chamber 81 and the second sterilization chamber 82. When the piston 2 moves left and right to compress or stretch the flexible tube 7, the total volume of the first sterilization chamber 81 and the second sterilization chamber 82 remains unchanged, thereby ensuring the air pressure balance of the first sterilization chamber 81 and the second sterilization chamber 82.

[0033] The first pump body 1a has two sealed chambers, namely a first sealed chamber A1 and a second sealed chamber B1, arranged left and right respectively. The left end of the first pump body 1a has a first interface and a second interface, both connected to the first sealed chamber A1. The first interface contains an A1-side inlet check valve A1-F1, and the second interface contains an A1-side outlet check valve A1-F2. The right end of the first pump body 1a has a third interface and a fourth interface, both connected to the second sealed chamber B1. The third interface contains a B1-side inlet check valve B1-F1, and the fourth interface contains a B1-side outlet check valve B1-F2. The second pump body 1b has two sealed chambers, namely a fourth sealed chamber B2 and a third sealed chamber A2, arranged left and right respectively. The right end of the second pump body 1b is provided with a fifth port and a sixth port, which are respectively connected to the third sealed chamber A2. The fifth port is equipped with an A2-side inlet check valve A2-F1, and the sixth port is equipped with an A2-side outlet check valve A2-F2. The left end of the second pump body 1b is provided with a seventh port and an eighth port, which are respectively connected to the fourth sealed chamber B2. The seventh port is equipped with a B2-side inlet check valve B2-F1, and the eighth port is equipped with a B2-side outlet check valve B2-F2. Specifically, the first and fifth ports are both connected to the liquid inlet pipe 9, the second and sixth ports are both connected to the liquid outlet pipe 10, the third and seventh ports are both connected to the waste liquid inlet pipe 11, and the fourth and eighth ports are both connected to the waste liquid outlet pipe 12. The eight check valves are used to control the flow direction of the liquid and prevent backflow. Specific structures include, but are not limited to, diaphragm type, ball bearing type, and duckbill type.

[0034] When the four pistons 2 are driven in conjunction by the electric cylinder drive linkage 6 and move towards the second sealed chamber B1 and the third sealed chamber A2, the liquid self-balancing process is as follows: external liquid is drawn into the first sealed chamber A1 through the liquid inlet pipe 9 and the A1-side inlet check valve A1-F1; external waste liquid is drawn into the fourth sealed chamber B2 through the waste liquid inlet pipe 11 and the B2-side inlet check valve B2-F1; waste liquid in the second chamber B1 is discharged into the waste liquid outlet pipe 12 through the B1-side outlet check valve B1-F2; and liquid in the third chamber A2 is discharged into the liquid outlet pipe 10 through the A2-side outlet check valve A2-F2.

[0035] When the four pistons 2 are driven in conjunction by the electric cylinder drive linkage 6 and move towards the first sealed chamber A1 and the fourth sealed chamber B2, the liquid self-balancing process is as follows: external waste liquid is drawn into the second sealed chamber B1 through the waste liquid inlet pipe 11 and the B1-side inlet check valve B1-F1; external liquid is drawn into the third sealed chamber A2 through the liquid inlet pipe 9 and the A2-side inlet check valve A2-F1; liquid in the first sealed chamber A1 is discharged into the liquid outlet pipe 10 through the A1-side outlet check valve A1-F2; waste liquid in the fourth sealed chamber B2 is discharged into the waste liquid outlet pipe 12 through the B2-side outlet check valve B2-F2.

[0036] In summary, by controlling the reciprocating motion of piston 2 through connecting rod 6, liquid can be alternately drawn into the first sealed chamber A1 and the third sealed chamber A2, and alternately discharged from the first sealed chamber A1 and the third sealed chamber A2 into the human body, while ensuring the continuity of liquid flow; at the same time, waste liquid can also be alternately drawn into the second sealed chamber B1 and the fourth sealed chamber B2, and alternately discharged from the second sealed chamber B1 and the fourth sealed chamber B2, so that waste liquid is removed from the human body, while ensuring the continuity of waste liquid flow. Because the cross-sectional areas of pistons 2 in the first sealed chamber A1, the second sealed chamber B1, the third sealed chamber A2, and the fourth sealed chamber B2 are the same and linked, the cooperation between the first sealed chamber A1 and the second sealed chamber B1, and the cooperation between the third sealed chamber A2 and the fourth sealed chamber B2, ensures that the volume changes of liquid and waste liquid are equal in real time. This guarantees that the liquid injected into the human body is equal to the liquid expelled in real time, thereby achieving automatic liquid balance. It has good tolerance to vibration and impact environments and is suitable for mobile applications. Furthermore, by controlling the rotation speed and number of revolutions of the electric cylinder, the movement speed and distance of piston 2 can be precisely controlled, thereby precisely controlling the flow rate and volume of inhaled and exhaled liquid and waste liquid. According to the patient's physical condition and the cross-sectional area of ​​piston 2, the movement speed of piston 2 can be controlled by controlling the electric cylinder to adapt the flow rate of liquid and waste liquid to the patient's body.

[0037] When multiple liquids need to be injected into the human body, multiple pumps of this invention (liquid self-balancing injection pump) can be used, each pump injecting one liquid into the human body and achieving the removal of an equal amount of waste liquid from the body. For example... Figures 3 to 7 The diagram illustrates an embodiment of three self-balancing liquid injection pumps integrated into a single housing 100. Each pump has three connecting rods 6 that drive four internal pistons 2 in a reciprocating motion, allowing for independent control of the three pumps. Each pump can inject liquid A, liquid B, and liquid C into the human body, while simultaneously removing waste liquid A, waste liquid B, and waste liquid C from the body.

[0038] The front shell plate of the housing 100 has a slot for exposing the three connecting rods 6 of the three self-balancing liquid injection pumps and for avoiding movement of the connecting rods 6. End caps 200 are respectively provided on the left and right sides of the housing 100, located on the left and right sides of the three self-balancing liquid injection pumps and connected to each pump through eight interfaces. The end caps 200 and the housing 100 are sealed together by welding, bonding, or threaded connection. The end caps 200 have internal liquid flow channels for the liquid inlet pipe 9, liquid outlet pipe 10, waste liquid inlet pipe 11, and waste liquid outlet pipe 12 of the three self-balancing liquid injection pumps, thus connecting the liquid paths. The input and output of waste liquid A, waste liquid B, and waste liquid C all converge through the liquid flow channels, thereby reducing the number of external interfaces.

[0039] Specifically, such as Figure 8 As shown, the flow paths for liquids A, B, and C, supplied to the human body by three self-balancing syringe pumps, are illustrated. The outlets / inlets for liquids A, B, and C are respectively located at... Figure 8 The left and right sides. For example... Figure 9 As shown, the liquid flow channels for waste liquid A, waste liquid B, and waste liquid C discharged from the human body by three self-balancing liquid syringe pumps are illustrated. The outlets / inlets of waste liquid A, waste liquid B, and waste liquid C are respectively located at... Figure 9 The left and right sides. For example... Figure 10 As shown, a liquid flow channel is provided to connect the waste liquids of three self-balancing liquid injection pumps. It includes six liquid holes 300, which are connected to the outlets and inlets of waste liquids A, B, and C, respectively. This allows the waste liquids to flow in from the upper right inlet and then be diverted to the three self-balancing liquid injection pumps through the three liquid holes 300 on the right side. The waste liquids flowing out of the three self-balancing liquid injection pumps are then combined through the three liquid holes 300 on the left side and flow out from the upper left outlet.

[0040] In use, this invention connects the liquid inlet pipe 9 to the dialysate, the liquid outlet pipe 10 to the dialysate inlet of the dialyzer, the waste liquid inlet pipe 11 to the waste liquid outlet of the dialyzer, and the waste liquid outlet pipe 12 to the waste liquid collection device. The volume changes of the dialysate and waste liquid are kept constant in real time by moving the connecting rod 6, ensuring that the injected and expelled liquids are equal, achieving liquid self-balancing. The movement speed and distance of the piston 2 can be precisely controlled by controlling the connecting rod 6 with the electric cylinder, thus precisely controlling the flow rate and volume of the injected and expelled liquids. Multiple units of this invention can be used when multiple liquids need to be injected into the body.

[0041] The main advantages of this utility model are as follows:

[0042] (1) The piston 2 and the inner cavity of the pump body form a structure similar to a syringe. Only by driving the piston 2 to move, it can be ensured that the liquid injected into the human body and the liquid removed are equal in real time, thereby achieving automatic liquid balance. By precisely controlling the movement speed and distance of the piston 2, the flow rate and volume of the liquid injected into the human body and the liquid removed can be precisely controlled.

[0043] (2) By alternately injecting liquid into the human body through the first closed chamber A1 and the third closed chamber A2, and alternately removing liquid from the human body through the second closed chamber B1 and the fourth closed chamber B2, the continuity of liquid flow can be improved.

[0044] (3) By using multiple of these inventions, multiple liquids can be injected into the human body and an equal amount of waste liquid can be removed from the human body; and by integrating multiple of these inventions into a single design, the internal liquid flow channel can be used to communicate the liquid path, thereby reducing external pipelines and simplifying installation operations.

[0045] (4) The control of liquid balance does not rely on high-precision sensors such as liquid flow meters, and it has good tolerance to vibration and shock environments, making it suitable for mobile applications.

[0046] (5) The liquid balance control and liquid pump are integrated into one unit, and the flow distribution is carried out by a one-way valve. Compared with the traditional balance chamber structure, the number of components is reduced, the structure is simplified, and the reliability is higher.

Claims

1. A self-balancing liquid injection pump, characterized in that: The system includes a first pump body (1a) and a second pump body (1b) with identical structures arranged vertically, a liquid inlet pipe (9), a liquid outlet pipe (10), a waste liquid inlet pipe (11), and a waste liquid outlet pipe (12). Each of the first pump body (1a) and the second pump body (1b) has two pistons (2) spaced along its length, which are movably and sealingly assembled with the inner cavity and divide the inner cavity into two sealed chambers and a sterilization air chamber (8) located between the two sealed chambers. A linkage rod (3) located in the corresponding sterilization air chamber (8) is fixedly connected between the two pistons (2) in the same pump body to achieve linkage between the two pistons (2). A connecting rod (6) is provided on the linkage rod (3) of the first pump body (1a) and the linkage rod (3) of the second pump body (1b), extending from the first pump body (1a) and the second pump body (1b) to drive the four pistons (2) to linkage. The first pump body (1a) has two sealed cavities, namely a first sealed cavity (A1) and a second sealed cavity (B1) arranged left and right. The left end of the first pump body (1a) has a first interface and a second interface respectively communicating with the first sealed cavity (A1), and the right end of the first pump body (1a) has a third interface and a fourth interface respectively communicating with the second sealed cavity (B1). The second pump body (1b) has two sealed cavities, namely a fourth sealed cavity (B2) and a third sealed cavity (A2) arranged left and right. The right end of the second pump body (1b) is provided with a fifth interface and a sixth interface that are respectively connected to the third sealed chamber (A2), and the left end of the second pump body (1b) is provided with a seventh interface and an eighth interface that are respectively connected to the fourth sealed chamber (B2); the first interface and the fifth interface are both connected to the liquid inlet pipe (9), the second interface and the sixth interface are both connected to the liquid outlet pipe (10), the third interface and the seventh interface are both connected to the waste liquid inlet pipe (11), and the fourth interface and the eighth interface are both connected to the waste liquid outlet pipe (12); The first interface is equipped with an A1-side inlet check valve (A1-F1), the second interface is equipped with an A1-side outlet check valve (A1-F2), the third interface is equipped with a B1-side inlet check valve (B1-F1), the fourth interface is equipped with a B1-side outlet check valve (B1-F2), the fifth interface is equipped with an A2-side inlet check valve (A2-F1), the sixth interface is equipped with an A2-side outlet check valve (A2-F2), the seventh interface is equipped with a B2-side inlet check valve (B2-F1), and the eighth interface is equipped with a B2-side outlet check valve (B2-F2).

2. A self-balancing liquid injection pump according to claim 1, characterized in that: The sterilization air chambers (8) of the first pump body (1a) and the second pump body (1b) are respectively provided with mounting seats (5) fixedly sleeved in the middle of the corresponding linkage rod (3) and perpendicular to the linkage rod (3); the connecting rod (6) is Y-shaped, and the two inner ends of the connecting rod (6) are respectively connected to the two mounting seats (5) one by one through the slot structure, and the outer end of the connecting rod (6) away from the two inner ends passes through the first pump body (1a) and the second pump body (1b).

3. A self-balancing liquid injection pump according to claim 2, characterized in that: The outer end of the connecting rod (6) is connected to an electric cylinder for driving the connecting rod (6) to move so as to drive the piston (2) in conjunction with the connecting rod (6).

4. A self-balancing liquid injection pump according to claim 2, characterized in that: The first pump body (1a) and the second pump body (1b) are respectively provided with openings for avoiding the connecting rod (6) when the connecting rod (6) moves; the first pump body (1a) and the second pump body (1b) are respectively provided with flexible tubes (7) symmetrically arranged on both sides of the corresponding mounting base (5) and connected to the corresponding mounting base (5) and the inner cavity respectively to block the corresponding openings to ensure the sealing of the corresponding sterilization air chamber (8) and to divide the corresponding sterilization air chamber (8) into the first sterilization air chamber (81) and the second sterilization air chamber (82).

5. A self-balancing liquid injection pump according to claim 4, characterized in that: The linkage rod (3) is provided with an air passage (4) for connecting the first sterilization air chamber (81) and the second sterilization air chamber (82) corresponding to it to ensure the air pressure balance between the first sterilization air chamber (81) and the second sterilization air chamber (82).

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