CN117138860A - Multichannel pipetting device - Google Patents

Abstract

The application relates to a multichannel pipetting device, which belongs to the technical field of medical detection and analysis equipment, and comprises a mounting plate, a fixed part, a plurality of tube bodies, a movable part and a linear motion mechanism, wherein the fixed part is provided with a plurality of first channels; one end of the pipe body is arranged in the first channel, and the other end of the pipe body is used for being inserted into the gun head; the movable piece is arranged below the fixed piece and sleeved on the pipe body; the linear motion mechanism at least can drive the movable piece to vertically move downwards; in the process of the vertical downward movement of the movable piece, the movable piece can push all gun heads to vertically move downward so as to separate the gun heads from the pipe body. The multichannel pipetting device provided by the application can separate a plurality of gun heads at one time without external equipment, is flexible to use, improves the efficiency of separating gun heads of the multichannel pipetting device, and further improves the test efficiency.

Description

Multichannel pipetting device

Technical Field

The application relates to the technical field of medical detection and analysis equipment, in particular to a multichannel pipetting device.

Background

Pipetting devices (e.g., pipetting guns) are a type of metering tool that transfers liquid from an original container to another container over a range of ranges and are widely used in the fields of biology, chemistry, medical detection and analysis, and the like. In the prior art, in order to improve pipetting efficiency, pipetting devices having a plurality of channels are commercially available. In order to avoid cross contamination in the experimental process, the gun head can be frequently removed, and each channel of the multichannel pipetting device is provided with the gun head, so that the problem of difficulty in removing the gun head exists, and the experimental efficiency is seriously reduced.

Disclosure of Invention

Based on this, it is necessary to provide a multi-channel pipetting device to solve the technical problem that the gun head of the multi-channel pipetting device is difficult to be removed in the prior art.

To achieve the above object, the present application provides a multi-channel pipetting device comprising:

a mounting plate;

the fixing piece is fixed on the mounting plate and provided with a plurality of first channels extending in the vertical direction;

the pipe bodies are in one-to-one correspondence with the first channels, the pipe bodies are positioned below the fixing piece, one end of each pipe body is arranged in each first channel, and the other end of each pipe body is used for being connected with the gun head in an inserting mode;

the movable piece is provided with a plurality of second channels which are in one-to-one correspondence with the first channels, is positioned below the fixed piece and is movably sleeved on the pipe body along the vertical direction; and

the linear motion mechanism is arranged on the mounting plate and can at least drive the movable piece to vertically move downwards;

in the process of the vertical downward movement of the movable piece, the movable piece can push all gun heads to vertically move downward so as to separate the gun heads from the pipe body.

Optionally, the multichannel pipetting device further comprises:

the photoelectric sensors are in one-to-one correspondence with the plurality of pipe bodies, the photoelectric sensors are arranged on the mounting plates at the side parts of the pipe bodies, the part of the pipe bodies corresponding to the photoelectric sensors is a detection part, and the part of the pipe bodies below the detection part is a stripping part; and

the multiple cylinders are arranged in one-to-one correspondence with the multiple tube bodies, the cylinders are movably sleeved on the tube bodies, the cylinders are located at the demolding and detecting parts when the tube bodies are not connected with the gun heads in an inserting mode, and the gun heads push the cylinders from the demolding and detecting parts to the detecting parts in the process of connecting the gun heads with the tube bodies.

Optionally, a plurality of contact surfaces corresponding to the plurality of cylinders one by one are arranged at the bottom of the movable part, and the plurality of contact surfaces have different horizontal heights.

Optionally, the level of the contact surface decreases from the middle to the two ends in the horizontal direction.

Optionally, be provided with the pole portion that extends along vertical direction on the outer peripheral face of barrel, pole portion protrusion barrel's top surface is provided with the first through-hole that supplies pole portion male corresponding pole portion on the moving part, is provided with first dog on the side of pole portion, is provided with the second dog on the internal face of first through-hole, and first dog is in the top of second dog.

Optionally, the top of the inner peripheral surface of the barrel is provided with a first annular gap, a first reset spring is installed in the first annular gap, and two ends of the first reset spring are respectively abutted to the bottom surface of the fixing piece and the bottom surface of the first annular gap, so that the barrel always has a trend of vertical downward movement.

Optionally, the first through hole communicates with the first channel.

Optionally, the photoelectric sensor is a groove type photoelectric sensor, a baffle extending along the vertical direction is arranged on the outer peripheral surface of the cylinder body, the baffle protrudes out of the top surface of the cylinder body, and the baffle can be inserted into and withdrawn from the groove type photoelectric sensor in the process of moving the cylinder body along the vertical direction.

Optionally, the linear motion mechanism includes:

the rotary driving piece is arranged on the mounting plate, and a rotating shaft of the rotary driving piece extends along the vertical direction;

the screw rod extends along the vertical direction and is connected with the rotating shaft; and

and the nut is arranged on the screw rod and moves along the vertical direction when the screw rod rotates.

Optionally, the fixing piece is provided with two third channels extending along the vertical direction, the top of the third channel is provided with a second annular gap, and the multichannel pipetting device further comprises:

the sliding rod is movably arranged in the third channel, two ends of the sliding rod are respectively protruded out of the movable piece, the bottom of the sliding rod is connected with the movable piece, and the top of the sliding rod is provided with an annular flange on the peripheral surface;

the second reset spring is arranged in the second annular notch, and two ends of the second reset spring are respectively abutted against the bottom surface of the annular flange and the bottom surface of the second annular notch, so that the sliding rod always has a trend of vertical upward movement; and

and the pressing plate is positioned above the sliding rod and connected with the nut, and is used for pressing the sliding rod so as to enable the sliding rod to vertically move downwards.

The multichannel pipetting device provided by the application has the beneficial effects that: compared with the prior art, the multichannel pipetting device comprises the mounting plate, the fixing piece, a plurality of tube bodies, the movable piece and the linear motion mechanism, wherein the fixing piece is provided with a plurality of first channels extending along the vertical direction, one ends of the tube bodies are arranged in the first channels, the other ends of the tube bodies are used for being inserted with gun heads, and therefore the mounting plate can drive all the tube bodies to move downwards through external equipment, and then a plurality of gun heads can be fetched once; the moving part is arranged below the fixed part and is movably sleeved on the pipe body along the vertical direction, and the linear motion mechanism at least can drive the moving part to vertically move downwards, so that in the process of vertically moving downwards, the moving part can push all gun heads to vertically move downwards so that the gun heads are separated from the pipe body, a plurality of gun heads can be separated at one time without external equipment, the use is flexible, the efficiency of the multi-channel pipetting device for removing the gun heads is improved, and the test efficiency is further improved.

Drawings

In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic perspective view of a multi-channel pipetting device according to an embodiment of the application;

fig. 2 is a schematic diagram of a three-dimensional structure of a multi-channel pipetting device according to an embodiment of the application;

FIG. 3 is a schematic cross-sectional view of a multi-channel pipetting device according to an embodiment of the application;

FIG. 4 is an enlarged view of FIG. 3 at A;

fig. 5 is a schematic diagram of a positional relationship between a cylinder and a photoelectric sensor of a multi-channel pipetting device according to an embodiment of the application.

Reference numerals illustrate:

1. a mounting plate;

2. a fixing member; 201. a first channel; 202. a third channel; 203. a second annular gap;

3. a tube body;

4. a movable member; 401. a second channel; 402. a contact surface; 403. a first through hole; 404. a second stopper;

5. a linear motion mechanism; 501. a rotary driving member; 502. a screw rod; 503. a nut;

6. a photoelectric sensor;

7. a cylinder; 701. a stem portion; 702. a first stopper; 703. a first annular gap; 704. a baffle;

8. a first return spring;

9. a slide bar; 901. An annular flange;

10. a second return spring; 11. A pressing plate; 12. A push rod;

100. gun head.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. 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 application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; 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 application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Referring to fig. 1 to 5, the embodiment of the present application provides a multi-channel pipetting device, which includes a mounting plate 1, a fixing member 2, a plurality of tube bodies 3, a movable member 4 and a linear motion mechanism 5, wherein the fixing member 2 is fixed on the mounting plate 1, and the fixing member 2 has a plurality of first channels 201 extending along a vertical direction; the pipe bodies 3 are in one-to-one correspondence with the first channels 201, the pipe bodies 3 are positioned below the fixing pieces 2, one end of each pipe body 3 is arranged in each first channel 201, and the other end of each pipe body 3 is used for being connected with the gun head 100 in an inserting mode; the movable piece 4 is provided with a plurality of second channels 401 which are in one-to-one correspondence with the plurality of first channels 201, the movable piece 4 is positioned below the fixed piece 2, and the movable piece 4 is movably sleeved on the pipe body 3 along the vertical direction; the linear motion mechanism 5 is arranged on the mounting plate 1, and the linear motion mechanism 5 at least can drive the movable piece 4 to vertically move downwards; wherein, during the vertical downward movement of the movable member 4, the movable member 4 can push all the gun heads 100 to move vertically downward so as to disengage the gun heads 100 from the pipe body 3.

In the embodiment of the application, the multichannel pipetting device comprises a mounting plate 1, a fixing piece 2, a plurality of tube bodies 3, a movable piece 4 and a linear motion mechanism 5, wherein the fixing piece 2 is provided with a plurality of first channels 201 extending along the vertical direction, one ends of the tube bodies 3 are arranged in the first channels 201, and the other ends of the tube bodies 3 are used for being inserted into gun heads 100, so that the mounting plate 1 can drive all the tube bodies 3 to move downwards through external equipment, and then a plurality of gun heads 100 are taken out at one time; the moving part 4 is located below the fixed part 2, the moving part 4 is movably sleeved on the pipe body 3 along the vertical direction, and the linear motion mechanism 5 can drive the moving part 4 to move vertically downwards at least, so that in the process of moving the moving part 4 vertically downwards, the moving part 4 can push all gun heads 100 to move vertically downwards so that the gun heads 100 are separated from the pipe body 3, a plurality of gun heads 100 can be separated at one time without the help of external equipment, the use is flexible, the efficiency of the gun head 100 of the multichannel pipetting device is improved, and the test efficiency is further improved.

In other embodiments, the mounting plate 1 is externally connected with an X-axis motion mechanism, a Y-axis motion mechanism and a Z-axis motion mechanism, the mounting plate 1 is driven to move in the horizontal direction by the X-axis motion mechanism and the Y-axis motion mechanism, the mounting plate 1 is driven to move in the vertical direction by the Z-axis motion mechanism, and the pipe body 3 is driven to move vertically downwards to plug the gun head 100.

It should be noted that, the multichannel pipetting device still has the problem that some gun heads 100 do not get when picking up gun heads 100, and the existing multichannel pipetting device generally only detects whether gun heads 100 are taken up or not, and whether gun heads 100 are taken up or not lacks detection, and the success rate and stability of experiments are directly affected by the fact that gun heads 100 are not taken up.

In one embodiment, referring to fig. 1 to 5 together, the multi-channel pipetting device further includes a plurality of photoelectric sensors 6 and a plurality of cylinders 7, the plurality of photoelectric sensors 6 are in one-to-one correspondence with the plurality of tubes 3, the photoelectric sensors 6 are mounted on the mounting plate 1 at the side of the tubes 3, a portion of the tubes 3 corresponding to the photoelectric sensors 6 is a detection portion, and a portion of the tubes 3 under the detection portion is a stripping portion; the plurality of cylinder bodies 7 are arranged in one-to-one correspondence with the plurality of pipe bodies 3, the cylinder bodies 7 are movably sleeved on the pipe bodies 3, the cylinder bodies 7 are positioned at the detaching and detecting part when the pipe bodies 3 are not connected with the gun heads 100 in an inserting mode, and the gun heads 100 push the cylinder bodies 7 from the detaching and detecting part to the detecting part in the process that the pipe bodies 3 are connected with the gun heads 100 in an inserting mode.

By the arrangement, only after the pipe body 3 is taken out of the gun head 100, the gun head 100 pushes the cylinder 7 from the detaching part of the pipe body 3 to the detecting part to trigger the photoelectric sensor 6; when the gun head 100 is not taken out of the pipe body 3, the cylinder 7 is always positioned at the detection removing part of the pipe body 3, and the photoelectric sensor 6 cannot be triggered. Thus, each tube 3 of the multichannel pipetting apparatus of the application is equipped with a photosensor 6, and whether each tube 3 is taken to the gun head 100 is monitored separately. Specifically, whether the cylinder 7 corresponding to the photoelectric sensor 6 moves upward can be determined according to whether the photoelectric sensor 6 is triggered, and whether the pipe 3 is taken out of the gun head 100 can be further determined. When judging that a certain pipe body 3 does not get the gun head 100, the gun head 100 is plugged downwards again through the Z-axis movement mechanism, so that the condition that the group of data is invalid due to the fact that part of pipe bodies 3 do not get the reagent is avoided, the time cost and the consumable cost are saved, and the experimental efficiency is improved.

It should be noted that, if the movable member 4 of the multi-channel pipetting device pushes all the cylinders 7 simultaneously, the static friction force of all the cylinders 7 needs to be overcome, and the movable member 4 needs a large power, which may put a large burden on the linear driving mechanism.

In a specific embodiment, referring to fig. 4, the bottom of the movable member 4 is provided with a plurality of contact surfaces 402 corresponding to the plurality of cylinders 7 one by one, and the plurality of contact surfaces 402 have different horizontal heights.

In this way, in the process that the movable member 4 moves vertically downwards, each contact surface 402 contacts with the corresponding cylinder 7 from the lowest to the highest in sequence to push down each cylinder 7 in a segmented manner according to the height of the horizontal, so that the power requirement of the movable member 4 is reduced, and the power requirement of the driving motor of the linear driving mechanism is further reduced. The driving motor has small power, small volume and weight, and the whole weight of the multichannel pipetting device is also small.

Illustratively, the bottom of the moveable member 4 is provided with grooves of varying depths, the side of the groove remote from the slot being the contact surface 402 for contacting the barrel 7.

In other embodiments, the bottom of the movable member 4 may be further provided with protrusions of different heights, the end faces of the protrusions being contact faces 402 for contacting the cylinder 7. In summary, the contact surface 402 is flexibly designed according to practical needs, and is not limited only herein.

In a more specific embodiment, referring to fig. 4, the contact surface 402 has a horizontal height that decreases from the middle to the ends in the horizontal direction.

Specifically, the positions of four contact surfaces 402 of the movable member 4 in the horizontal direction from the edge to the inside are shown in fig. 4, the horizontal heights of the contact surfaces 402 in the horizontal direction from the edge to the inside are increased, and the horizontal heights of the four contact surfaces 402 in the horizontal direction from the edge to the inside are respectively referred to as a line, b line, c line and d line in fig. 4.

In other embodiments, the level of the contact surface 402 may further increase from the middle to the two ends in the horizontal direction according to actual requirements, or the level of the contact surface 402 may be arranged in a preset order, which is not limited herein.

In another specific embodiment, referring to fig. 4 and 5, a rod portion 701 extending along a vertical direction is disposed on an outer circumferential surface of the cylinder 7, the rod portion 701 protrudes from a top surface of the cylinder 7, a first through hole 403 for inserting the rod portion 701 is disposed on the movable member 4 corresponding to the rod portion 701, a first stop 702 is disposed on a side surface of the rod portion 701, a second stop 404 is disposed on an inner wall surface of the first through hole 403, and the first stop 702 is located above the second stop 404.

By the above arrangement, the second stopper 404 can be overlapped by the first stopper 702, so as to limit the downward movement of the second stopper 404 (i.e. the cylinder 7) and prevent the cylinder 7 from falling from the tube 3.

In one embodiment, referring to fig. 3 to 5 together, a first annular gap 703 is provided at the top of the inner peripheral surface of the cylinder 7, a first return spring 8 is installed in the first annular gap 703, and two ends of the first return spring 8 are respectively abutted against the bottom surface of the fixing member 2 and the bottom surface of the first annular gap 703, so that the cylinder 7 always has a tendency to move vertically downward.

In this way, the first return spring 8 makes the cylinder 7 always have a vertical downward movement trend, so that the cylinder 7 cannot be easily moved to the detection portion of the pipe body 3 under the influence of external environment (such as upward jump of the cylinder 7 caused by vibration, etc.), and the possibility of misjudgment of the photoelectric sensor 6 is reduced.

Meanwhile, the first reset spring 8 also plays a certain auxiliary role when the movable piece 4 downwards pushes the cylinder 7, so that the difficulty of removing the gun head 100 is reduced.

In one embodiment, referring to fig. 4, the first through hole 403 communicates with the first channel 201.

In this way, when the rod 701 of the cylinder 7 is installed in the first through hole 403, the rod 701 can extend into the first channel 201 and then enter the first through hole 403, so that the possibility of mutual interference between the first stop block 702 and the second stop block 404 is reduced, and the installation difficulty of the cylinder 7 is reduced.

In one embodiment, referring to fig. 5, the photoelectric sensor 6 is a slot type photoelectric sensor, a baffle 704 extending in a vertical direction is disposed on an outer circumferential surface of the cylinder 7, the baffle 704 protrudes from a top surface of the cylinder 7, and the baffle 704 can be inserted into and withdrawn from the slot type photoelectric sensor during movement of the cylinder 7 in the vertical direction.

Specifically, the groove-shaped photoelectric sensor is formed by arranging a light emitter and a receiver face to face on two sides of a groove. The light emitter can emit infrared light or visible light, and the light receiver can receive the light without any resistance. However, when the detected object passes through the groove, the light is blocked, the photoelectric switch acts, a switch control signal is output, and the load current is cut off or switched on, so that one control action is completed.

By the arrangement, only when the baffle 704 of the cylinder 7 is inserted into the groove-shaped photoelectric sensor, a switch control signal is output, and compared with other types of photoelectric sensors, the groove-shaped photoelectric sensor is not easy to be interfered by external environments, and the detection precision is high.

In one embodiment, referring to fig. 2, the linear motion mechanism 5 includes a rotary driving member 501, a screw rod 502, and a nut 503, the rotary driving member 501 is mounted on the mounting plate 1, and a rotation axis of the rotary driving member 501 extends in a vertical direction; the screw rod 502 extends along the vertical direction and is connected with the rotating shaft; the nut 503 is mounted on the screw 502, and the nut 503 moves in a vertical direction when the screw 502 rotates.

Further, the multichannel pipetting device is further provided with a slide rail and a slide seat, the nut 503 is mounted on the slide seat, and the slide rail and the slide seat can play a role in guiding the linear movement of the nut 503.

In one embodiment, referring to fig. 2, two third channels 202 extending along a vertical direction are provided on the fixing member 2, a second annular notch 203 is provided at the top of the third channels 202, the multi-channel pipetting device further includes a slide bar 9, a second return spring 10 and a pressing plate 11, the slide bar 9 is movably installed in the third channels 202, two ends of the slide bar 9 protrude from the movable member 4 respectively, the bottom of the slide bar 9 is connected with the movable member 4, and an annular flange 901 is provided at the top of the slide bar 9 on the outer peripheral surface; the second reset spring 10 is arranged in the second annular notch 203, and two ends of the second reset spring 10 are respectively abutted against the bottom surface of the annular flange 901 and the bottom surface of the second annular notch 203, so that the sliding rod 9 always has a trend of vertical upward movement; the pressing plate 11 is located above the slide bar 9 and connected with the nut 503, and the pressing plate 11 is used for pressing the slide bar 9 to move the slide bar 9 vertically downward.

Through setting up as above, after clamp plate 11 accomplishes a pressing action and upwards breaks away from slide bar 9, slide bar 9 can upwards automatic re-set under the effect of second reset spring 10, need not the manual movable part 4 that resets of staff, reduces staff's work load, improves this multichannel pipetting device's degree of automation, can also reduce the waiting time that takes off rifle head 100 next.

In other implementations, the multi-channel pipetting device further includes a push rod 12, the top of the push rod 12 is connected to the platen 11, the bottom of the push rod is sealed and movably mounted in the first channel 201, and the push rod 12 is used for exhausting air in the first channel 201, so that negative pressure is generated in the first channel 201, and further, reagents are sucked into the gun head 100.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims (10)

1. A multi-channel pipetting device comprising:

a mounting plate;

the fixing piece is fixed on the mounting plate and is provided with a plurality of first channels extending in the vertical direction;

the pipe bodies are in one-to-one correspondence with the first channels, the pipe bodies are positioned below the fixing pieces, one ends of the pipe bodies are arranged in the first channels, and the other ends of the pipe bodies are used for being connected with gun heads in an inserting mode;

the movable piece is provided with a plurality of second channels which are in one-to-one correspondence with the first channels, is positioned below the fixed piece and is movably sleeved on the pipe body along the vertical direction; and

the linear motion mechanism is arranged on the mounting plate and at least can drive the movable piece to vertically move downwards;

and in the process of vertically moving downwards, the movable piece can push all the gun heads to vertically move downwards so as to separate the gun heads from the pipe body.

2. The multi-channel pipetting device of claim 1, further comprising:

the photoelectric sensors are in one-to-one correspondence with the plurality of pipe bodies, the photoelectric sensors are arranged on the mounting plates at the side parts of the pipe bodies, the part of the pipe bodies corresponding to the photoelectric sensors is a detection part, and the part of the pipe bodies below the detection part is a stripping part; and

the tube bodies are arranged in one-to-one correspondence, the tube bodies are movably sleeved on the tube bodies, the tube bodies are located at the demolding and detecting parts when the tube bodies are not inserted into the gun heads, and the gun heads push the tube bodies from the demolding and detecting parts to the detecting parts in the process of inserting the tube bodies into the gun heads.

3. The multi-channel pipetting device of claim 2 wherein the bottom of the movable member is provided with a plurality of contact surfaces in one-to-one correspondence with a plurality of the cylinders, the plurality of contact surfaces having different levels.

4. A multichannel pipetting device according to claim 3, wherein the level of the contact surface decreases from the middle to the two ends in the horizontal direction.

5. The multichannel pipetting device according to claim 2, wherein a rod extending in the vertical direction is provided on the outer circumferential surface of the cylinder, the rod protrudes out of the top surface of the cylinder, a first through hole into which the rod is inserted is provided on the movable member corresponding to the rod, a first stopper is provided on the side surface of the rod, a second stopper is provided on the inner wall surface of the first through hole, and the first stopper is located above the second stopper.

6. The multichannel pipetting apparatus according to claim 5, wherein a first annular gap is provided at the top of the inner peripheral surface of the cylinder, a first return spring is installed in the first annular gap, and two ends of the first return spring are respectively abutted to the bottom surface of the fixing member and the bottom surface of the first annular gap, so that the cylinder always has a tendency of vertical downward movement.

7. The multi-channel pipetting device of claim 5, wherein the first through-hole communicates with the first channel.

8. The multi-channel pipetting device of claim 5, wherein the photosensor is a slot-type photosensor, a baffle extending in the vertical direction is provided on the outer peripheral surface of the cylinder, the baffle protrudes out of the top surface of the cylinder, and the baffle can be inserted into and withdrawn from the slot-type photosensor during the movement of the cylinder in the vertical direction.

9. The multi-channel pipetting device of claim 1, wherein the linear motion mechanism comprises:

the rotary driving piece is arranged on the mounting plate, and a rotating shaft of the rotary driving piece extends along the vertical direction;

the screw rod extends along the vertical direction and is connected with the rotating shaft; and

and the nut is arranged on the screw rod, and moves along the vertical direction when the screw rod rotates.

10. The multi-channel pipetting device of claim 9 wherein the fixture is provided with two vertically extending third channels, the top of the third channels being provided with a second annular gap, the multi-channel pipetting device further comprising:

the sliding rod is movably arranged in the third channel, two ends of the sliding rod are respectively protruded out of the movable piece, the bottom of the sliding rod is connected with the movable piece, and the top of the sliding rod is provided with an annular flange on the peripheral surface;

the second reset spring is arranged in the second annular notch, and two ends of the second reset spring are respectively abutted against the bottom surface of the annular flange and the bottom surface of the second annular notch, so that the sliding rod always has a trend of vertical upward movement; and

and the pressing plate is positioned above the sliding rod and connected with the nut, and is used for pressing the sliding rod so as to enable the sliding rod to move vertically downwards.