CN220715900U

CN220715900U - Large-scale volume high-precision pump-connected pipetting device

Info

Publication number: CN220715900U
Application number: CN202321901794.XU
Authority: CN
Inventors: 傅国; 吴彬
Original assignee: Hunan Boshuo Biotechnology Co ltd
Current assignee: Hunan Boshuo Biotechnology Co ltd
Priority date: 2023-07-18
Filing date: 2023-07-18
Publication date: 2024-04-05
Anticipated expiration: 2033-07-18

Abstract

The utility model provides a large-scale volume high-precision pump-connected pipetting device, and belongs to the technical field of pipetting pumps. The large-scale high-precision combined pump pipetting device comprises an air pump device and a driving mechanism which are arranged in a shell; the air pump device comprises a first pump body component, a second pump body component and a gun head component, wherein the gun head component is connected below the first pump body component, and the first pump body component and the second pump body component are connected through an air pipe; the driving mechanism drives the first pump body component to finish transferring small-volume liquid, and drives the second pump body component to finish transferring large-volume liquid. The application provides a device for automatic liquid workstation large tracts of land high accuracy liquid transfer adopts self-adaptation gas-liquid to change and combines together, accomplishes large tracts of land high accuracy liquid transfer, and its process degree of automation is high, can the overall arrangement flux be big, efficient, and the multichannel variable interval scope to the small volume liquid transfer requirement of high flux is little, guarantees the openness and the adaptability of liquid transfer pump.

Description

Large-scale volume high-precision pump-connected pipetting device

Technical Field

The utility model belongs to the technical field of liquid transferring pumps, and particularly relates to a large-scale volume high-precision combined pump liquid transferring device.

Background

The automatic workstation for sample pretreatment is an automatic operation platform of a molecular diagnosis laboratory which skillfully fuses liquid treatment and automatic operation together, and can realize operations such as code scanning, automatic sample adding, reagent distribution, solution transfer, oscillation, heating, magnetism and the like related to liquid treatment. The method is widely applied to aspects such as nucleic acid extraction and purification, gene sequencing, biological sample library and the like.

The current pipetting device is a core mechanism of an automated workstation for molecular diagnosis pretreatment and is used for realizing the actions of sucking, transferring, distributing, conveying and the like of liquid among containers. In the current commercial automated sample pretreatment workstations, the most commonly used standard liquid holding containers are 96-well plates, 48-well plates, 8-well plates, etc. Wherein, the space between adjacent holes of a standard liquid container such as a 96-well plate commonly used in a laboratory is 9mm, 8 holes are distributed in a single row, and 12 rows are arranged. Therefore, the design of the automatic workstation needs to realize a plurality of pipetting mechanisms (1-8 pipetting mechanisms complete pipetting actions simultaneously or respectively) with high precision and high repeatability in a small space range, so that high-efficiency automatic batch processing is realized.

Pipetting devices are typically implemented in the form of pipetting pumps and microfluidics. Micro-flow control mainly realizes micro-solution transfer, and a liquid transfer pump usually completes solution transfer with a larger volume range, is limited by the prior commercialization and technical barriers, and usually has a small volume range (10-200 ul, 200ul-1000ul, 1000ul-3000ul, 3000ul-5000 ul) for transferring the solution, thereby limiting the expansion of a full-automatic mode and the integration of an automatic mode.

In the prior art, three types of application are seen, firstly, a single plunger in a pump body is independently driven, and the method is applied to operation with high requirements on small and medium volume accuracy. Defects: single application and poor self-adaptability. And secondly, a plurality of plungers in the pump body are connected in parallel with a linear mechanism for driving, so that the pump is applied to medium-small-volume high-efficiency operation, and the number of channels is 96, 192 or more according to the application requirements. Defects: high cost, extremely high debugging requirements and precision requirements (such as parallelism and flatness), huge volume, pseudo-large volume and easy pollution. In addition, the traditional plastic or glass cavity and the plastic plunger have wide application range and can realize large volume and small volume. Defects: the automatic degree is extremely low, the speed is low, the flux is low, the volume is large, the service life is short, and different volumes need to be switched.

Disclosure of Invention

The utility model solves the problems in the prior art by providing the large-scale high-precision combined pump pipetting device which fully automatically realizes the high-precision effect of small-volume pipetting and also takes account of large-volume high-flux pipetting.

In order to achieve the above object, the technical solution of the present utility model is:

a large-scale volume high-precision combined pump pipetting device comprises an air pump device and a driving mechanism, wherein the air pump device and the driving mechanism are arranged in a shell; the air pump device comprises a first pump body component, a second pump body component and a gun head component, wherein the gun head component is connected below the first pump body component, and the first pump body component and the second pump body component are connected through an air pipe; the driving mechanism drives the first pump body component to finish transferring small-volume liquid, and drives the second pump body component to finish transferring large-volume liquid.

Preferably, the first pump body assembly comprises a first cylinder body and a first piston rod, the first cylinder body consists of a base, an air passage adapter and a cylinder cover, the base, the air passage adapter and the cylinder cover form a coaxial central through hole in the cylinder body, and the first piston rod is arranged in the central through hole; the bottom end and the side surface of the first piston rod are provided with a first through hole with a three-way structure, a second through hole communicated with the central through hole is arranged in the gas circuit adapter body, and the second through hole is connected with the gas pipe;

the second pump body assembly comprises a second cylinder body and a second piston rod, the second cylinder body is a central through hole, one end of the second cylinder body is connected with the second piston rod, and the other end of the second cylinder body is connected with the gas circuit adapter through a gas pipe.

Preferably, the driving mechanism comprises a first driving mechanism and a second driving mechanism, the first driving mechanism comprises a first driving motor, a first screw rod assembly and a guide post, the first screw rod assembly comprises a first screw rod, a first nut and a movable bridge seat, the first screw rod is connected with the first nut, the movable bridge seat is fixed on the first nut, the top end of the first piston rod is connected with the movable bridge seat, the first screw rod is fixed on the first driving motor, and the first driving motor is fixed on the shell; the guide post penetrates through the movable bridge seat on the first screw rod assembly and is parallel to the first screw rod, and the guide post is connected with the first pump body assembly; the movable bridge seat is provided with a first light blocking piece; the first driving mechanism drives the first piston rod to move in the central through hole, so that the first through hole can correspond to the second through hole;

the second driving mechanism comprises a second driving motor and a second screw rod assembly, the second screw rod assembly comprises a second screw rod and a second nut, the second screw rod is connected with the second nut, the top end of the second piston rod is connected with the second nut, and the second screw rod is fixed on the second driving motor; the second driving motor is connected with the second screw rod assembly to provide the liquid sucking and discharging driving force of the second pump body assembly.

Preferably, the air pipe is arranged in the guide post, one end of the air pipe extends out of the shell, the other end of the air pipe is connected with the second through hole, and a tee joint structure is formed with the second through hole.

Preferably, the upper part of the base and the lower part of the cylinder cover are cylindrical convex structures, two ends of the gas circuit adapter are cylindrical concave structures, the cylindrical convex structures and the cylindrical concave structures share a central axis, the cylindrical convex structures can be inserted into the cylindrical concave structures, and the length of the convex cylinder is smaller than the depth of the concave.

Preferably, a connecting hole is formed in the outer portion of the base of the first cylinder body, and a first sealing ring is arranged at the connecting hole to form a first sealing ring;

second sealing rings are respectively designed in the column-shaped concave structures at the two ends of the gas circuit adapter body to form second sealing rings;

two sections of grooves are arranged in the column-shaped convex structures on the upper part of the base and the lower part of the cylinder cover, and third sealing rings are respectively arranged on the grooves to form third sealing rings.

Preferably, the gun head assembly comprises a gun head adapter and an adapter sleeve assembly, wherein the gun head adapter is mounted on the adapter sleeve assembly and is connected with the central through hole.

Preferably, the center position of rifle head adapter is equipped with the through-hole, and the bottom is equipped with first arch and second arch, and the second is protruding to be greater than first arch, rifle head adapter top is equipped with the spacing ring, and the spacing ring external diameter is greater than adapter sleeve subassembly internal diameter.

Preferably, the adapter sleeve assembly comprises a top connection sleeve, a spring, a top rod and a second light blocking sheet, wherein the top connection sleeve is connected with the top rod, the spring is sleeved on the top rod at the joint of the top connection sleeve and the top rod, two ends of the spring respectively abut against the joint of the top connection sleeve and the top rod, and the limit position of the spring on the top rod, and the second light blocking sheet is arranged at one end far away from the top rod and is parallel to the top rod.

Preferably, the pipetting device is further provided with an induction device, the induction device comprises a displacement original point sensor, a reset sensor, an air pressure sensor and a capacitance sensor, and the displacement original point sensor is arranged between the movable bridge seat and the ejector rod and is close to the top end of the ejector rod; the reset sensor is arranged at one end far away from the ejector rod and is parallel to the ejector rod; the air pressure sensor is arranged at the external connecting hole of the first cylinder body base; the capacitive sensor is arranged at the joint of the gun head adapter and the cylinder base.

The beneficial effects of the utility model are as follows:

the scheme provides a device for large-scale high-precision pipetting of an automatic liquid workstation, is different from a pneumatic pump of a traditional high-flux automatic pipetting workstation, adopts self-adaptive gas-liquid conversion to combine together to finish large-scale high-precision pipetting, has high process automation degree, large placeable flux and high efficiency, and ensures the openness and the adaptability of a pipetting pump according to the multi-channel variable spacing range required by high-flux small-volume pipetting.

Drawings

Fig. 1 is a schematic perspective view of the present utility model.

Fig. 2 is a schematic plan view of the present utility model.

Fig. 3 is a schematic perspective view of a first pump body assembly.

Fig. 4 is a schematic view of the first pump body assembly with the first piston rod down.

Fig. 5 is a schematic view of the first pump body assembly with the first piston rod upward.

FIG. 6 is a schematic cross-sectional view of a first pump body assembly.

FIG. 7 is a schematic cross-sectional view of a second pump body assembly.

In the figure: 10. a first pump body assembly; 20. a second pump body assembly; 30. a gun head assembly; 40. a first driving mechanism; 50. a second driving mechanism; 11. a first cylinder; 12. a first piston rod; 13. a base; 14. an air passage adapter; 15. a cylinder cover; 16. a first through hole; 17. a second through hole; 18. an air pipe; 21. a second cylinder; 22. a second piston rod; 31. a gun head adapter; 32. an adapter sleeve assembly; 33. a first protrusion; 34. a second protrusion; 35. a sleeve is propped and connected; 36. a push rod; 37. a second light blocking sheet; 41. a first driving motor; 42. a guide post; 43. a first screw rod; 44. a first nut; 45. a movable bridge seat; 46. a first light blocking sheet; 51. a second driving motor; 52. a second screw rod; 61. a first seal ring; 62. a second seal ring; 63. a third seal ring; 64. a fourth seal ring; 70. an air pressure sensor; 71. a capacitive sensor.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present utility model are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.

Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present utility model, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present utility model, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In addition, the technical solutions of the embodiments of the present utility model may be combined with each other, but it is necessary to be based on the fact that those skilled in the art can implement the technical solutions, and when the technical solutions are contradictory or cannot be implemented, the combination of the technical solutions should be considered as not existing, and not falling within the scope of protection claimed by the present utility model.

Referring to fig. 1 to 7, a large-scale volume high-precision combined pump pipetting device comprises an air pump device and a driving mechanism which are arranged in a shell; the air pump device comprises a first pump body assembly 10, a second pump body assembly 20 and a gun head assembly 30, wherein the gun head assembly 30 is connected below the first pump body assembly 10, and the first pump body assembly 10 and the second pump body assembly 20 are connected through an air pipe 18; the driving mechanism drives the first pump body assembly 10 to finish transferring small-volume liquid, and drives the second pump body assembly 20 to finish transferring large-volume liquid. The first pump body assembly 10 described above performs small volume (10-1000 uL) fluid intake and discharge, and is connected to the second pump body assembly 20 via the air line 18, and when it is desired to perform large volume fluid transfer exceeding 1000uL, the second pump body assembly 20 is actuated to provide large volume fluid intake and discharge pressure.

Specifically, the first pump body assembly 10 includes a first cylinder body 11 and a first piston rod 12, where the first cylinder body 11 is composed of a base 13, an air passage adapter 14 and a cylinder cover 15, and the base 13, the air passage adapter 14 and the cylinder cover 15 form a coaxial central through hole inside the cylinder body, and the first piston rod 12 is disposed in the central through hole; the bottom end and the side surface of the first piston rod 12 are provided with a first through hole 16 with a three-way structure, the air passage adapter 14 is internally provided with a second through hole 17 communicated with the central through hole, and the second through hole 17 is connected with an air pipe 18;

the second pump body assembly 20 comprises a second cylinder body 21 and a second piston rod 22, the second cylinder body 21 is a central through hole, one end of the second cylinder body 21 is connected with the second piston rod 21, and the other end of the second cylinder body is connected with the air passage adapter 14 through an air pipe 18.

The driving mechanism comprises a first driving mechanism 40 and a second driving mechanism 50, the first driving mechanism 40 comprises a first driving motor 41, a first screw rod assembly and a guide post 42, the first screw rod assembly comprises a first screw rod 43, a first nut 44 and a movable bridge seat 45, the first screw rod 43 is connected with the first nut 44, the movable bridge seat 45 is fixed on the first nut 44, the top end of the first piston rod 12 is connected with the movable bridge seat 45, the first screw rod 43 is fixed on the first driving motor 41, and the first driving motor 41 is fixed on the shell; the guide post 42 passes through a movable bridge seat 45 on the first screw rod 43 assembly and is arranged parallel to the first screw rod 43, and the guide post 42 is connected with the first pump body assembly 10; the movable bridge seat 45 is provided with a first light blocking piece 46, and the first light blocking piece 46 is arranged towards the direction of the pump body; the first driving mechanism 40 drives the first piston rod 12 to move in the central through hole, so that the first through hole 16 can correspond to the second through hole 17;

the second driving mechanism 50 comprises a second driving motor 51 and a second screw rod 52 assembly, the second screw rod 52 assembly comprises a second screw rod 52 and a second nut, the second screw rod 52 is connected with the second nut, the top end of the second piston rod 21 is connected with the second nut, and the second screw rod 52 is fixed on the second driving motor 51; the second driving motor 51 is connected to the second screw assembly to provide the suction and discharge liquid driving force of the second pump body assembly 20.

The air pipe 18 is arranged in the guide post 42, one end of the air pipe 18 extends out of the shell, the other end of the air pipe is connected with the second through hole 17, and a three-way structure is formed with the second through hole 17.

The pump body component is a gas-liquid conversion pump, and liquid is sucked and discharged through the change of positive and negative pressure of gas. The pump body assembly comprises a first pump body assembly 10 and a second pump body assembly 20, and the first pump body assembly and the second pump body assembly are used together with a driving mechanism to meet the requirement of self-adaptive large-scale volume high-precision pipetting. The first pump body assembly 10 is responsible for transferring small-volume (10-1000 ul) liquid, and the second pump body assembly 20 and the first pump body assembly 10 are jointly responsible for transferring large-volume liquid. The diameter of the closed cavity of the first pump body assembly 10 is small and long, so that the small-volume pipetting accuracy is ensured, and meanwhile, the requirement of high flux on the small volume of the pipetting pump is met. The diameter of the closed cavity of the second pump body assembly 20 is matched with the length and the diameter according to the requirement of the pipetting volume and the equipment installation requirement (the formula is V=pi×R ² X L). The second pump body component 20 is connected with the first pump body component 10 through the air pipe 18, and the air pipe 18 is made of soft materials, so that the second pump body component 20 can be fixed at a certain position, and only the first pump body component 10 can perform three-dimensional movement in space, thereby ensuring the requirements of high flux of the full-automatic liquid workstation on small volume, light weight and accurate movement of the mechanical arm.

The upper part of the base 13 and the lower part of the cylinder cover 15 are cylindrical convex structures, two ends of the air passage adapter 14 are cylindrical concave structures, the cylindrical convex structures and the cylindrical concave structures share a central axis, the cylindrical convex structures can be inserted into the cylindrical concave structures, and the length of the convex cylinder is smaller than the depth of the concave.

Further, a connecting hole is formed on the outer portion of the cylinder base 13, the connecting hole is connected with the pressure sensing device 70, and a first sealing ring 61 is arranged at the connecting hole to form a first sealing ring; second sealing rings 62 are respectively designed in the column-shaped concave structures at the two ends of the gas circuit adapter 14 to form second sealing rings; two sections of grooves are formed in the column-shaped convex structures at the upper part of the base 13 and the lower part of the cylinder cover 15, and third sealing rings 63 are respectively arranged on the grooves to form third sealing rings; a fourth sealing ring 64 is arranged between the second cylinder 21 and the second piston rod 21 to form a fourth sealing ring.

Further, the gun head assembly 30 comprises a gun head adapter 31 and an adapter sleeve assembly 32, the gun head adapter 31 is mounted on the adapter sleeve assembly 32, and the gun head adapter 31 is connected with the center through hole. Preferably, a through hole is arranged at the center of the gun head adapter 31, a first protrusion 33 and a second protrusion 34 are arranged at the bottom, the second protrusion 34 is larger than the first protrusion 33, a limiting ring is arranged at the top end of the gun head adapter 31, the outer diameter of the limiting ring is larger than the inner diameter of the adapter sleeve assembly 32, and the outer diameter of the limiting ring is not larger than 9mm. The gun head adapter 31 and the adapter sleeve assembly 32 described above are both implemented using existing products.

Still further, the adapter sleeve assembly 32 includes a top connection sleeve 35, a spring, a push rod 36 and a second light blocking piece 37, the top connection sleeve 35 is connected with the push rod 36, and the longitudinal central axis of the push rod 36 is perpendicular to the transverse central line of the movable bridge seat 45 and is in the same plane; the joint of the jacking sleeve 35 and the ejector rod 36 is provided with a spring, the spring is sleeved on the ejector rod 36, two ends of the spring respectively prop against the joint of the jacking sleeve 35 and the ejector rod 36 and the limit position of the spring on the ejector rod 36, and the second light blocking piece 37 is arranged at one end far away from the ejector rod 36 and parallel to the ejector rod 36.

The adaptor sleeve assembly 32 is used for realizing automatic gun head removal, and the adaptor sleeve is moved by the motor to extrude the gun head out of the gun head adaptor 31, so that the automatic gun head removal is realized by liquid transfer, and the liquid workstation is fully automated. The manner in which the adapter sleeve assembly is used is accomplished using prior art techniques. In the use process, the automatic induction of the gun head of the adapter is that the sensor provides the controller with the change of the position signal, thereby realizing the judgment of the taking-off of the gun head and carrying out error alarm. The automatic gun removing head is to provide signal software instructions to control the motor to operate the gun removing head through the sensor. The gun head disengaging state is set, and the original position of the adapter sleeve is signal 1. When the gun head is picked up, the adapter sleeve presses the elastic mechanism, and the sensor provides a position signal 2 to the control module, and then the gun head is determined to be picked up. When the control module receives a gun head removing command and sends a driving motor operation command in combination with the position signal 2, the driving motor provides the acting force of the ejector rod 36, so that the ejection sleeve 35 is displaced, the gun head is separated from the gun head adapter 31, the elastic mechanism of the adapter sleeve returns to the original state, and the sensor provides the position signal 1 for the control module, so that the gun head is judged to be separated.

Further, the pipetting device is further provided with a sensing device, and the sensing device comprises a displacement origin sensor, a resetting sensor, an air pressure sensor 70 and a capacitance sensor 71.

The displacement origin sensor is arranged between the movable bridge seat 45 and the ejector rod 36 and is close to the top end of the ejector rod 36 and used for sensing the origin reset of the piston rod, and the origin reset of the piston rod is to provide signals for the control module through the displacement origin sensor to acquire whether the piston rod is at the origin position, so that the starting position of the movement of the piston rod is consistent every time and whether the operation of the driving mechanism is normal or not is detected.

The reset sensor is arranged at one end far away from the ejector rod and parallel to the ejector rod and is used for sensing the position change of the adapter sleeve, the position change of the adapter sleeve also provides signals for the control module through the sensor to acquire the position change of the adapter sleeve, when the gun head is taken out, the adapter sleeve extrudes the elastic mechanism to move upwards to provide the position signal change so as to determine that the gun head is taken out, when the gun head is taken off, the adapter sleeve moves downwards to restore the reset position to provide the position signal change so as to determine that the gun head is taken off.

The air pressure sensor 70 is arranged at the external connecting hole of the cylinder base 13, and the air pressure value is sensed by sealing the probe of the air pressure sensor 70 in the closed cavity. The capacitance sensor is installed at the junction of the gun head adapter 31 and the cylinder base 13.

Working principle:

the first pump body component structure is relatively complex, and the switching between the two pump bodies is realized in a mechanical principle mode. The cylinder body of the first pump body component comprises a base, an air passage adapter body and a cylinder cover, wherein the base and the air passage adapter body form a first cavity, a first piston rod is used for completing liquid suction and discharge of a small volume (10-1000 uL) in the first cavity, and the volume of the first cavity is set to be larger than 1000uL so as to cover conversion of a 1000uL critical point. The air passage adapter, the cylinder cover and the second air pump device form a second cavity, when the requirement of absorbing and discharging the large-volume liquid of more than 1000uL is met, the software sends out an instruction, the first piston rod continues to operate until the through hole on the side face of the first piston rod coincides with the connecting hole of the second cavity, namely, the first through hole corresponds to the second through hole, the air pressure sensor senses the pressure change, the first piston rod stops operating, and the first pump body component is synchronized to operate so as to provide the pressure of absorbing and discharging the large-volume liquid.

This application adopts lead screw and piston rod parallel structure, when guaranteeing enough stroke, avoids same axle center overlength and the operation instability that brings to make the length and width of design structure more reasonable satisfy automatic liquid platform to the demand of pipetting pump space three-dimensional motion.

The application has the following specific effects:

the application adopts self-adaptive gas-liquid conversion design, and has high pipetting accuracy, wide application range and high automation degree. One pump is multipurpose, the pipetting range is wide and the seamless connection is realized, and the technical barrier for the full automation requirement of the high-throughput liquid workstation on the large-volume pipetting is opened. The modular design, the electric part and the mechanical part are integrated independently, so that the cost is greatly reduced while the diversified components are optimized. Automatic gun head induction ensures that the device is small in size, and simultaneously integrates automatic gun head removing function, one driving mechanism achieves multiple functions, mutual interference is avoided, efficiency is greatly improved, and biohazard risk is reduced. The pump body is compact in structure, the pump body meets the requirement of large-volume pipetting, the volume is small, the minimum arrangement distance is 9mm, and the automation requirement of the large-volume high-flux existing commercial mode is realized.

The foregoing description is only illustrative of the present utility model and is not intended to limit the scope of the utility model, and all equivalent structures or equivalent processes or direct or indirect application in other related technical fields are included in the scope of the present utility model.

Claims

1. The large-scale high-precision pump-connected pipetting device is characterized by comprising an air pump device and a driving mechanism, wherein the air pump device and the driving mechanism are arranged in a shell; the air pump device comprises a first pump body component, a second pump body component and a gun head component, wherein the gun head component is connected below the first pump body component, and the first pump body component and the second pump body component are connected through an air pipe; the driving mechanism drives the first pump body assembly to finish transferring small-volume liquid amount, and drives the second pump body assembly to finish transferring large-volume liquid amount;

the first pump body assembly comprises a first cylinder body and a first piston rod, the first cylinder body consists of a base, an air passage adapter and a cylinder cover, the base, the air passage adapter and the cylinder cover form a coaxial central through hole in the cylinder body, and the first piston rod is arranged in the central through hole; the bottom end and the side surface of the first piston rod are provided with a first through hole with a three-way structure, a second through hole communicated with the central through hole is arranged in the gas circuit adapter body, and the second through hole is connected with the gas pipe;

2. The large-scale high-precision pump-connected pipetting device according to claim 1, wherein the driving mechanism comprises a first driving mechanism and a second driving mechanism, the first driving mechanism comprises a first driving motor, a first screw rod assembly and a guide post, the first screw rod assembly comprises a first screw rod, a first nut and a movable bridging seat, the first screw rod is connected with the first nut, the movable bridging seat is fixed on the first nut, the top end of the first piston rod is connected with the movable bridging seat, the first screw rod is fixed on the first driving motor, and the first driving motor is fixed on the shell; the guide post penetrates through the movable bridge seat on the first screw rod assembly and is parallel to the first screw rod, and the guide post is connected with the first pump body assembly; the movable bridge seat is provided with a first light blocking piece; the first driving mechanism drives the first piston rod to move in the central through hole, so that the first through hole can correspond to the second through hole;

3. The large-scale high-precision pump-connected pipetting device according to claim 2, wherein the air pipe is arranged in the guide post, one end of the air pipe extends out of the shell, the other end of the air pipe is connected with the second through hole, and the air pipe and the second through hole form a three-way structure.

4. The large-scale high-precision pump-connected pipetting device according to claim 1, wherein the upper part of the base and the lower part of the cylinder cover are cylindrical convex structures, two ends of the gas circuit adapter are cylindrical concave structures, the cylindrical convex structures and the cylindrical concave structures share a central axis, the cylindrical convex structures can be inserted into the cylindrical concave structures, and the length of the convex cylinders is smaller than the depth of the concave structures.

5. The large-scale high-precision pump-connected pipetting device according to claim 4, wherein a connecting hole is formed outside the base of the first cylinder body, and a first sealing ring is arranged at the connecting hole to form a first sealing ring;

6. The high-precision pump-connected pipetting device of claim 1 wherein the gun head assembly comprises a gun head adapter and an adapter sleeve assembly, the gun head adapter is mounted on the adapter sleeve assembly, and the gun head adapter is connected with the central through hole.

7. The high-precision pump-connected pipetting device with large volume as recited in claim 6 wherein a through hole is provided in the center of the gun head adapter, a first protrusion and a second protrusion are provided at the bottom, the second protrusion is larger than the first protrusion, a stop collar is provided at the top of the gun head adapter, and the outer diameter of the stop collar is larger than the inner diameter of the adapter sleeve assembly.

8. The large-scale high-precision pump-connected pipetting device according to claim 6, wherein the adapter sleeve assembly comprises a top connection sleeve, a spring, a top rod and a second light blocking sheet, the top connection sleeve is connected with the top rod, the spring is arranged at the joint of the top connection sleeve and the top rod and sleeved on the top rod, two ends of the spring respectively abut against the joint of the top connection sleeve and the top rod, and the limit position of the spring on the top rod, and the second light blocking sheet is arranged at one end far away from the top rod and is parallel to the top rod.

9. The large-scale high-precision pump-connected pipetting device according to any one of claims 6 to 8, wherein an induction device is further arranged on the pipetting device, the induction device comprises a displacement origin sensor, a reset sensor, an air pressure sensor and a capacitance sensor, and the displacement origin sensor is arranged between the movable bridging seat and the ejector rod and is close to the top end of the ejector rod; the reset sensor is arranged at one end far away from the ejector rod and is parallel to the ejector rod; the air pressure sensor is arranged at the external connecting hole of the first cylinder body base; the capacitive sensor is arranged at the joint of the gun head adapter and the cylinder base.