Multi-channel pipettor

Abstract

The utility model discloses a multichannel pipettor which comprises a handle base body, a pipette head and a suction head, a multichannel and a multichannel piston rod synchronous execution connecting rod are arranged in the pipette head, piston cylinder assemblies are respectively installed in the multichannel, and a buffer and a pipette withdrawing push plate are further arranged in the pipette head. The buffer and the gun retreating push plate are arranged to achieve self-adaptive suction head installation and automatic gun retreating, the spring guide rod, the compression spring and the piston cylinder in the buffer are not concentric, the buffer enables the piston cylinder to have an independent buffering function, the installation space of a multi-channel inner piston cylinder assembly is not occupied, the inner space of the gun head is fully and compactly utilized, and the service life of the gun head is prolonged. The range is increased; the automatic gun withdrawing device is provided with the gun withdrawing push plate with a sectional gun withdrawing function, the suction head is pushed out in a sectional mode, automatic gun withdrawing is completed, and the automatic gun withdrawing device is suitable for automatic gun withdrawing of the suction head of the wide-range multi-channel pipettor; the runway-shaped piston cylinder, the piston and the sealing ring are arranged, so that the measuring range of the multi-channel pipettor is greatly increased under the condition that the axial length is not increased.

Description

Technical Field

[0001] The utility model relates to the technical field of pipettes, in particular to a multi-channel pipette. Background Art

[0002] In biological laboratories or clinical laboratories, multichannel pipettes are commonly used precision instruments for accurately transferring liquids. Multichannel pipettes usually include a handle base, a gun head and a suction tip, and a multi-channel piston cylinder assembly is arranged in the gun head. When installing the suction tip, in order to ensure the sealing, researchers need to move the piston head of the piston cylinder assembly into the suction tip as much as possible so that the suction tip and the piston head are tightly combined. However, in this process, due to the different installation forces of the suction tip, it is easy for the suction tip to be installed too loosely or too tightly, especially for the adaptation of different types of suction tips (different types of suction tips require different depths of insertion into the gun tip), it is very easy for the suction tip to be installed improperly.

[0003] A too loose fit may result in inaccurate pipetting due to a poor seal between the tip and the piston head. This may cause liquid leakage or errors when aspirating liquid. An overly tight fit may cause frustration for the operator because more force is required to insert and remove the piston head from the tip. In addition, an overly tight fit may cause wear between the piston head and the tip, shortening their service life.

[0004] Therefore, most of the existing multi-channel pipettes have a spring assembly connected to the piston cylinder to achieve adaptive tip installation, and an automatic gun retraction structure is designed to achieve automatic gun retraction of the pipette tip.

[0005] However, with the increasing requirements for the range of multi-channel pipettes, the existing design structure can no longer meet the requirements. Since the spacing between the piston heads of multi-channel pipettes needs to be kept at a fixed distance of 9mm, for pipettes with a large range, without increasing the axial length, it is necessary to redesign the adaptive tip installation structure and automatic gun retraction structure to make full use of the space in the pipette to obtain a multi-channel pipette with a range of more than 1000 microliters. Utility Model Content

[0006] In order to solve the above technical problems, the utility model designs a multi-channel pipette.

[0007] The utility model adopts the following technical solutions:

[0008] A multi-channel pipette, comprising a handle base, a gun head and a suction head, wherein a driving device is installed in the handle base, a multi-channel and a multi-channel piston rod synchronously executing connecting rod are arranged in the gun head, a piston cylinder assembly is respectively installed in the multi-channel, the driving device drives the multi-channel piston rod synchronously executing the connecting rod to synchronously lift and lower to drive each piston cylinder assembly to complete the suction and discharge actions, and the gun head also includes a buffer and a gun retracting push plate;

[0009] The buffer provides the same buffer force for each piston-cylinder assembly, and is used for the adaptive assembly of the suction head at the head of the piston-cylinder assembly;

[0010] The gun-retracting push plate is a split type, including a fixed seat and a movable seat. The fixed seat is fixedly installed in the gun head, and the movable seat rises and falls and slides along the fixed seat. A suction head limiting surface is set on the bottom surface of the fixed seat, and a suction head pushing surface is set on the bottom surface of the movable seat. Multiple channels correspond to the suction head limiting surface and the suction head pushing surface to form multiple channel holes. In conjunction with the guide installation of the head of each piston cylinder assembly, gun-retracting end surfaces are set on both sides of the movable seat, and the gun-retracting push plate contact ends are correspondingly provided on both sides of the multi-channel piston rod synchronous execution connecting rod, which is used to drive the suction head pushing surface of the movable seat to be pushed out by descending the multi-channel piston rod synchronous execution connecting rod, so as to realize automatic gun retraction of the suction head;

[0011] A tension spring is connected between the upper part of the inner shell of the gun head and the end face of the gun withdrawal, which is used for the automatic return of the moving seat after the multi-channel piston rod synchronously executes the connecting rod to rise.

[0012] Preferably, the piston cylinder assembly comprises a piston rod, a piston cylinder and a piston connected to the bottom of the piston rod, the piston cylinder comprises a piston cylinder body and a piston cylinder head, and the piston cylinder head is installed in the channel hole for connecting the suction head.

[0013] Preferably, the buffer includes a fixed plate, a spring guide rod, a compression spring and a compression end face. The fixed plate is fixed on the inner shell of the gun head. The fixed plate is provided with corresponding slide grooves with the same number of channels. A connecting hole is provided at the bottom of each slide groove. The spring guide rod is installed through the connecting hole. The guide rod head is installed in the slide groove. The compression spring is sleeved on the spring guide rod. The bottom of the spring guide rod is integrally provided with a compression end face, and the compression end face is pressed against the piston cylinder end face of the piston cylinder.

[0014] Preferably, each multi-channel pipette has two buffers inside, and the compression end faces of the two buffers are respectively pressed against the two side positions of the piston cylinder end face in the corresponding channel, and the spring guide rod, the compression spring and the piston cylinder are not concentric.

[0015] Preferably, the suction head pushing surface of the movable seat is stepped and has a plurality of pushing contact surfaces. After the movable seat descends, the plurality of pushing contact surfaces contact the suction heads in the corresponding channels in sections, thereby realizing automatic section-wise withdrawal of the suction heads.

[0016] Preferably, the plurality of pushing contact surfaces are distributed in a stepped manner from both sides to the middle, including a first contact surface, a second contact surface, a third contact surface and a fourth contact surface.

[0017] Preferably, the multi-channel piston rod synchronous execution connecting rod includes an extension rod, a connecting rod and a piston rod mounting groove arranged on the connecting rod that is consistent with the number of multiple channels. The upper end of the extension rod is the connecting rod power end, which is used to connect the driving device, and the lower end is fixedly connected to the connecting rod. The two sides of the connecting rod are correspondingly provided with gun retracting push plate contact ends.

[0018] Preferably, a spring mounting hole is provided on the gun retracting end face, a fixing column is installed on the upper part of the inner shell of the gun head, a tension spring is fixedly connected between the spring mounting hole and the fixing column, and the tension spring and the contact end of the gun retracting push plate are staggered up and down.

[0019] Preferably, the fixing seat is provided with a plurality of fixing seat slots, and the fixing seat is fixedly connected to the inner shell of the gun head via the fixing seat slots.

[0020] Preferably, the piston rod includes a piston rod connecting rod, the upper end of the piston rod connecting rod is a piston rod head, a rubber plug is installed on the piston rod head, a groove is provided on the outside of the piston connected to the bottom of the piston rod, a runway-shaped sealing ring is fixedly connected through the groove, and stop limit surfaces are provided on both sides of the piston cylinder body, and the stop limit surfaces are pressed against the limit surfaces on the inner shell of the gun head.

[0021] Preferably, the cross-sections of the piston barrel, cylinder body and piston are correspondingly arranged in a racetrack shape, and the sealing ring is also correspondingly arranged in a racetrack shape. For multi-channel pipettes with a large range of more than 1000 microliters, multi-channel pipettes with a small range of less than 1000 microliters such as 10 microliters, 100 microliters, 300 microliters, etc. still use sealing rings, piston barrels, cylinder bodies and pistons with circular cross-sections.

[0022] The beneficial effects of the present invention are as follows: (1) the present invention is provided with a buffer and a gun-retracting push plate to realize adaptive tip installation and automatic gun retraction. The spring guide rod, compression spring and piston cylinder in the buffer are not concentric. The buffer enables the piston cylinder to have an independent buffering function, does not occupy the installation space of the piston cylinder assembly in the multi-channel, fully and compactly utilizes the internal space of the gun head, and improves the measuring range; (2) the present invention is provided with a gun-retracting push plate with a segmented gun-retracting function, which pushes out the tip in segments to complete automatic gun retraction, and is suitable for automatic gun retraction of the tip of a large-range multi-channel pipette; (3) the runway-shaped piston cylinder, piston and sealing ring are arranged, which greatly improves the measuring range of the multi-channel pipette without increasing the axial length. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the utility model;

[0024] Figure 2 It is a structural schematic diagram of the buffer in the utility model;

[0025] Figure 3It is a structural schematic diagram of a multi-channel piston rod synchronously executing a connecting rod in the utility model;

[0026] Figure 4 This is a structural schematic diagram of the gun-retracting push plate in the utility model;

[0027] Figure 5 It is a schematic diagram of the structure inside the gun head of the utility model;

[0028] Figure 6 This is a structural schematic diagram of the piston cylinder assembly in the utility model;

[0029] In the figure: 1. handle base, 2. gun retraction button, 3. display, 4. run button, 5. motor, 6. lead screw, 7. multi-channel piston rod synchronous execution connecting rod, 8. connecting rod power end, 9. buffer, 10. front shell, 11. piston cylinder assembly, 12. rear shell, 13. gun retraction push plate, 14. suction head, 15. fixing plate, 16. slide groove, 17. guide rod head, 18. connecting hole, 19. spring guide rod, 20. compression spring, 21. compression end face, 22. extension rod, 23. connecting rod, 24. piston rod mounting groove, 25. gun retraction push plate connection Contact end, 26, gun retraction end face, 27, fixed column, 28, tension spring, 29, fixed seat, 30, movable seat, 31, fixed seat slot, 32, suction head limiting surface, 33, first contact surface, 34, second contact surface, 35, third contact surface, 36, fourth contact surface, 37, channel hole, 38, spring mounting hole, 39, piston cylinder, 40, piston cylinder end face, 41, stop limit surface, 42, piston cylinder head, 43, piston rod, 44, rubber plug, 45, piston rod head, 46, piston rod connecting rod, 47, slot, 48, sealing ring. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0031] Example: Figure 1 As shown, a multi-channel pipette includes a handle base 1, a gun head and a suction head 14. A motor 5 and a lead screw 6 are arranged in the handle base 1. A gun retraction button 2, a display 3 and a run button 4 are arranged on the handle base 1. The motor 5 rotates to drive the lead screw 6 to rotate and lift. The gun head includes a housing, a multi-channel piston rod synchronous execution connecting rod 7, a buffer 9, a gun retraction push plate 13 and a piston cylinder assembly 11. The suction head 14 is installed on the piston cylinder head 45 of the piston cylinder assembly 11. The housing includes a front shell 10 and a rear shell 12, and the front shell 10 and the rear shell 12 are fixed by snapping. The connecting rod power end 8 of the multi-channel piston rod synchronous execution connecting rod 7 is fixedly connected to the lead screw 6, and is driven to lift and lower through the lead screw 6. The lifting and lowering of the multi-channel piston rod synchronous execution connecting rod 7 drives each piston cylinder assembly 11 to complete the liquid suction and discharge actions.

[0032] like Figure 2 As shown, the buffer 9 includes a fixed plate 15, a spring guide rod 19, a compression spring 20 and a compression end face 21. The fixed plate 15 is provided with corresponding slide grooves 16 with the same number of channels. A connecting hole 18 is provided at the bottom of each slide groove. The spring guide rod 19 is installed through the connecting hole 18. The guide rod head 17 is installed in the slide groove 16. The compression spring 20 is sleeved on the spring guide rod 19. The bottom of the spring guide rod 19 is integrally provided with a compression end face 21. The compression end face 21 presses against the piston cylinder end face 40 of the piston cylinder 39. Each multi-channel pipette has two buffers 9 inside. The compression end faces 21 on the two buffers 9 are respectively pressed against the two sides of the piston cylinder end face 40 in the corresponding channel. The spring guide rod 19, the compression spring 20 and the piston cylinder 39 are not concentric. The piston rod 43 of the piston cylinder assembly 11 is located in the middle of the two buffers 9. The fixed plates 15 of the two buffers 9 are respectively fixedly connected to the front shell 10 and the rear shell 12 of the gun head.

[0033] like Figure 3 As shown, the multi-channel piston rod synchronous execution connecting rod 7 includes an extension rod 22, a connecting rod 23 and a piston rod mounting groove 24 arranged on the connecting rod with the same number of channels. The piston rod mounting groove 24 is used to install the piston rod head 45 in the piston cylinder assembly 11. The upper end of the extension rod 22 is the connecting rod power end 8, which is used to connect the screw, and the lower end is fixedly connected to the connecting rod 23. The two sides of the connecting rod 23 are correspondingly provided with gun retracting push plate contact ends 25.

[0034] like Figure 4 As shown, the gun retracting push plate 13 is a split type, including a fixed seat 29 and a movable seat 30. The movable seat 30 rises and falls and slides along the fixed seat 29. A suction head limiting surface 32 is set on the bottom surface of the fixed seat 29, and a suction head pushing surface is set on the bottom surface of the movable seat 30. Multiple channels are formed between the suction head limiting surface 32 and the suction head pushing surface to form multiple channel holes 37 corresponding to multiple channels. In conjunction with the guide installation of the head of each piston cylinder assembly 11, gun retracting end surfaces 26 are set on both sides of the movable seat 30, and corresponding gun retracting push plate contact ends 25 are set on both sides of the multi-channel piston rod synchronous execution connecting rod 7, which are used to drive the suction head pushing surface of the movable seat 30 to be pushed out by the descent of the multi-channel piston rod synchronous execution connecting rod 7, so as to realize automatic gun retracting of the suction head. The tip push surface of the movable seat 30 is provided with four push contact surfaces in a stepped shape. The four push contact surfaces are distributed in a stepped shape from both sides to the middle, and are respectively the first contact surface 33, the second contact surface 34, the third contact surface 35 and the fourth contact surface 36. After the movable seat 30 descends, the four push contact surfaces contact the tip 14 in the corresponding channel in sections, so as to realize the automatic withdrawal of the tip in sections. Three fixed seat slots 31 are provided on the fixed seat 29, and the fixed seat 30 is fixedly connected to the front shell 10 of the gun head through the fixed seat slots 31. A spring mounting hole 38 is provided on the withdrawal end surface 26.

[0035] like Figure 5As shown, a fixing column 27 is installed on the upper part of the inner shell of the gun head, and a tension spring 28 is fixedly connected between the spring installation hole 38 and the fixing column 37. The tension spring 28 is staggered up and down with the contact end 25 of the gun retracting push plate. The tension spring 28 is used for the automatic return of the moving seat 30 after the multi-channel piston rod synchronously executes the connecting rod 7 to rise.

[0036] like Figure 6 As shown, the piston cylinder assembly 11 includes a piston rod 43, a piston cylinder 39 and a piston connected to the bottom of the piston rod 43. The piston cylinder 39 includes a piston cylinder body and a piston cylinder head 42. The piston cylinder head 42 is installed in the channel hole 37 and is used to connect the suction head 14. The cross-sections of the piston cylinder body and the piston are correspondingly set to a runway shape. The piston rod 43 includes a piston rod connecting rod 46. The upper end of the piston rod connecting rod 46 is a piston rod head 45. A rubber plug 44 is installed on the piston rod head. A slot 47 is set outside the piston connected to the bottom of the piston rod 43. A runway-shaped sealing ring 48 is fixedly connected through the slot 47. Stop limit surfaces 41 are set on both sides of the bottom of the piston cylinder body. The stop limit surfaces 41 press against the limit surfaces on the inner shell of the gun head.

[0037] The use principle of the utility model is:

[0038] When loading the suction tip, put the suction tip 14 on the piston cylinder head 42, and press down the handheld multi-channel pipette to tighten it. At this time, the suction tip 14 pushes the piston cylinder 39 upward, and the piston cylinder 39 moves upward. Each piston cylinder 39 is limited by two compression springs 20 to ensure that in the absence of external force, the stop limit surface 41 of the piston cylinder 39 is in contact with the front shell 10 and the rear shell 12. At this time, the compression spring 20 is in a slightly compressed state. When the piston cylinder 39 moves upward, the compression spring 20 is compressed until the end of the suction tip 14 contacts the suction tip limit surface 32, the compression stops, and the compression spring 20 is in a maximum compression state. At this time, stop the downward pressure, lift the pipette and the suction tip, the piston cylinder 39 automatically returns to its position under the action of the compression spring 20, and the suction tip is adaptively installed to a suitable depth.

[0039] When aspirating liquid, press the operation button 4, the motor 5 drives the screw 6 to move upward, and the end of the screw is rigidly connected with the multi-channel piston rod through the connecting rod power end 8 and the connecting rod 7 synchronously executes the multi-channel piston rod, and moves upward at the same time until the limit position, completing the liquid aspiration action.

[0040] During the discharge, after the liquid suction action is completed, the operation button 4 is continued to be pressed, the motor 5 drives the lead screw 6 to move downward, and the piston rod 43 moves downward to complete the discharge action.

[0041] When blowing liquid, double-click the operation button 4, the motor 5 drives the lead screw 6 to move downward a short distance and return to the discharge completion position, and the piston rod 43 simultaneously moves downward a short distance and returns to the discharge completion position, completing the blowing action.

[0042] When the gun is automatically retracted, the gun retracting button 2 is pressed, and the motor 5 drives the lead screw 6 to move downward, and the gun retracting push plate contact end portions 25 at both ends of the multi-channel piston rod synchronous execution connecting rod 7 contact the gun retracting end surfaces 26 at both ends of the gun retracting push plate 13. The multi-channel piston rod synchronous execution connecting rod 7 continues to move downward, the tension spring 28 begins to be stretched, and the mobile end 30 leaves the initial position. The multi-channel piston rod synchronous execution connecting rod 7 pushes the mobile end 30 to move downward until the first contact surface 33 contacts the two suction heads 14 at both ends. The mobile end 30 continues to move downward, and the two suction heads 14 at both ends are separated from the piston cylinder head 42. The mobile end 30 continues to move downward until the second contact surface 34 contacts the corresponding two suction heads 14. The mobile end 30 continues to move downward, and the corresponding two suction heads 14 are separated from the piston cylinder head 42. The mobile end 30 continues to move downward until the third contact surface 35 contacts the corresponding two suction heads 14. The mobile end 30 continues to move downward, and the corresponding two suction heads 14 are separated from the piston cylinder head 42. The moving end 30 continues to move downward until the fourth contact surface 36 contacts the two middle suction heads 14. The moving end 30 continues to move downward, and the two middle suction heads 14 are separated from the piston cylinder head 42, thus completing the segmented automatic withdrawal of all suction heads 14.

[0043] Then the motor 5 drives the screw 6 to move upward, and the multi-channel piston rod synchronously executes the connecting rod 7 to move upward synchronously with the screw 6. The movable end 30 moves upward due to the action of the tension spring 28 until it returns to the initial position. At this time, the contact end 25 of the gun retracting push plate is no longer in contact with the gun retracting end surface 26 at both ends of the gun retracting push plate 13, and the gun retracting action is completed.

[0044] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A multi-channel pipette, comprising a handle base (1), a gun head and a suction head (14), wherein a driving device is installed in the handle base (1), a multi-channel and a multi-channel piston rod synchronous execution connecting rod (7) are arranged in the gun head, and a piston cylinder assembly (11) is respectively installed in the multi-channel, and the driving device drives the multi-channel piston rod synchronous execution connecting rod (7) to synchronously rise and fall to drive each piston cylinder assembly (11) to complete the suction and discharge action, wherein the driving device drives the multi-channel piston rod synchronous execution connecting rod (7) to synchronously rise and fall to drive each piston cylinder assembly (11) to complete the suction and discharge action, wherein the driving device drives the multi-channel piston rod synchronous execution connecting rod (7) to synchronously rise and fall to drive each piston cylinder assembly (11) to complete the suction and discharge action, and ... The gun head also includes a buffer (9) and a gun retracting push plate (13); The buffer (9) provides the same buffer force for each piston cylinder assembly (11) and is used for adaptive assembly of the head suction head (14) of the piston cylinder assembly (11); The gun retracting push plate (13) is a split type, comprising a fixed seat (29) and a movable seat (30), wherein the fixed seat (29) is fixedly installed in the gun head, and the movable seat (30) is lifted and slid along the fixed seat (29), a suction head limiting surface (32) is arranged on the bottom surface of the fixed seat (29), and a suction head pushing surface is arranged on the bottom surface of the movable seat (30), and a plurality of channel holes (37) are formed by corresponding multi-channels between the suction head limiting surface (32) and the suction head pushing surface, and the gun retracting end surfaces (26) are arranged on both sides of the movable seat (30) in cooperation with the guide installation of the head of each piston cylinder assembly (11), and the gun retracting push plate contact end portions (25) are correspondingly arranged on both sides of the multi-channel piston rod synchronous execution connecting rod (7), which are used to drive the suction head pushing surface of the movable seat (30) to be pushed out by descending the multi-channel piston rod synchronous execution connecting rod (7), so as to realize automatic gun retracting of the suction head (14); A tension spring (28) is connected between the upper portion of the inner shell of the gun head and the gun retracting end surface (26) and is used for the multi-channel piston rod to synchronously execute the automatic return of the moving seat (30) after the connecting rod (7) rises.

2. The multichannel pipette according to claim 1, characterized in that: The piston cylinder assembly (11) comprises a piston rod (43), a piston cylinder (39) and a piston connected to the bottom of the piston rod (43); the piston cylinder (39) comprises a piston cylinder body and a piston cylinder head (42); the piston cylinder head (42) is installed in the channel hole (37) and is used to connect to the suction head (14).

3. The multichannel pipette according to claim 2, characterized in that: The buffer (9) comprises a fixed plate (15), a spring guide rod (19), a compression spring (20) and a compression end face (21). The fixed plate (15) is fixed to the inner shell of the gun head. The fixed plate (15) is provided with corresponding slide grooves (16) with the same number as the channels. A connecting hole (18) is provided at the bottom of each slide groove (16). The spring guide rod (19) is installed through the connecting hole (18). The guide rod head (17) is installed in the slide groove (16). The compression spring (20) is sleeved on the spring guide rod (19). The bottom of the spring guide rod (19) is integrally provided with a compression end face (21). The compression end face (21) is pressed against the piston cylinder end face (40) of the piston cylinder (39).

4. The multichannel pipette according to claim 3, characterized in that: Each multi-channel pipette has two buffers (9) inside, and the compression end surfaces (21) on the two buffers (9) are respectively pressed against the two sides of the piston cylinder end surface (40) in the corresponding channel, and the spring guide rod (19), the compression spring (20) and the piston cylinder (39) are not concentric.

5. The multichannel pipette according to claim 1, characterized in that: The suction head pushing surface of the movable seat (30) is provided with a plurality of pushing contact surfaces in a stepped shape. After the movable seat (30) descends, the plurality of pushing contact surfaces contact the suction heads (14) in corresponding channels in sections, thereby realizing automatic section-wise withdrawal of the suction heads (14).

6. The multichannel pipette according to claim 5, characterized in that: The plurality of pushing contact surfaces are distributed in a stepped manner from both sides to the middle, and include a first contact surface (33), a second contact surface (34), a third contact surface (35) and a fourth contact surface (36).

7. The multichannel pipette according to claim 1, characterized in that: The multi-channel piston rod synchronous execution connecting rod (7) comprises an extension rod (22), a connecting rod (23) and a piston rod mounting groove (24) arranged on the connecting rod (23) in accordance with the number of the multi-channels. The upper end of the extension rod (22) is a connecting rod power end (8) for connecting to a driving device, and the lower end is fixedly connected to the connecting rod (23). Gun retracting push plate contact ends (25) are correspondingly arranged on both sides of the connecting rod (23).

8. The multichannel pipette according to claim 1, characterized in that: A spring mounting hole (38) is provided on the gun retracting end surface (26), a fixing column (27) is installed on the upper part of the inner shell of the gun head, a tension spring (28) is fixedly connected between the spring mounting hole (38) and the fixing column (27), and the tension spring (28) is staggered with the contact end (25) of the gun retracting push plate in the upper and lower parts.

9. The multichannel pipette according to claim 1, characterized in that: The fixing seat (29) is provided with a plurality of fixing seat slots (31), and the fixing seat (29) is fixedly connected to the inner shell body of the gun head via the fixing seat slots (31).

10. The multichannel pipette according to claim 2, characterized in that: The piston rod (43) comprises a piston rod connecting rod (46), the upper end of the piston rod connecting rod (46) is a piston rod head (45), a rubber plug (44) is installed on the piston rod head (45), a piston connected to the bottom of the piston rod (43) is provided with a slot (47) outside, a sealing ring (48) is fixedly connected through the slot (47), and stop limit surfaces (41) are provided on both sides of the piston cylinder body, and the stop limit surfaces (41) are pressed against the limit surfaces on the inner shell of the gun head.

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