High-reliability pipetting pump

Abstract

The utility model discloses a high reliability pipetting pump which comprises a driving motor, a driving support, a lead screw, a nut, a pipetting cavity and a plunger, the pipetting cavity is internally provided with a pipetting cavity extending in the vertical direction, at least part of the plunger is contained in the pipetting cavity, and the nut reciprocates in the vertical direction to drive the plunger to reciprocate in the pipetting cavity; wherein the surface roughness Ra of the inner side of the pipetting cavity is greater than or equal to 6.4. According to the high-reliability pipetting pump disclosed by the utility model, by increasing the surface roughness of the inner side of the pipetting cavity, crystals separated out from a solution preferentially grow on the inner surface of the pipetting cavity, and the probability that the crystals separated out from the solution are attached to the plunger is reduced, so that the risk that a sealing ring is scratched by a large number of separated crystals on the plunger is reduced; the use reliability of the pipetting pump is improved, the use safety of the pipetting pump is improved, and the service life is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of automation medical treatment especially, a kind of high reliability pipette pump. BACKGROUND

[0002] High-precision pipette pump is widely used in automated medical instrument, for accurate quantitative suction and discharge liquid, high-precision pipette pump is usually driven by stepper motor, when stepper motor driver receives the pulse signal transmitted by controller, drive stepper motor rotates corresponding angle in set direction, then through the cooperation action of screw rod and nut, rotary motion is converted into linear motion, so that plunger moves up and down in cavity to change volume to achieve the purpose of suction or discharge liquid.

[0003] Currently, the plunger is generally selected from ceramic material with good reagent resistance. The ceramic material is easy to form, has high hardness, and a smooth surface for sealing. The sealing ring is selected from ultra-high molecular polyethylene (high molecular material) with extremely low friction coefficient and good corrosion resistance.

[0004] The precision of the existing pipette pump can be accurate to microliter, but there are still reliability problems in the industry. Since most of the working medium of the pipette pump is a solution that can precipitate crystals, the precipitated crystals can easily adhere to the ceramic plunger after the equipment is used for a period of time. As the crystals continue to precipitate and grow, the hard crystals can scratch the sealing ring when the plunger moves up and down, causing liquid leakage. The leaked medium is often corrosive, which can seriously damage the internal circuit of the equipment and cause serious consequences.

[0005] Therefore, it is necessary to design a pipette pump that can prevent crystals from forming on the plunger and thus avoid scratching the sealing ring. UTILITY MODEL CONTENTS

[0006] The utility model embodiment provides a kind of high reliability pipette pump, to solve the problem that traditional pipette pump is easily formed in the process of using, crystal, scratch sealing ring and cause the problem of liquid leakage.

[0007] To solve the above technical problems, the utility model embodiment provides

[0008] A kind of high reliability pipette pump, including drive motor, drive support, screw rod, nut, pipette cavity and plunger,

[0009] The screw rod and the nut are arranged on the drive support, and the drive motor is used to drive the screw rod to rotate around the axial direction of the screw rod. The screw rod is threadedly connected with the nut, and the nut can reciprocate along the up-down direction relative to the drive support. The rotation of the screw rod can drive the nut to reciprocate along the up-down direction.

[0010] The pipetting cavity is fixedly connected with the driving support, the pipetting cavity is located above the thimble, a pipetting cavity extending in the up-down direction is arranged in the pipetting cavity, one end of the plunger is fixedly connected with the thimble, the other end of the plunger extends into the pipetting cavity, at least part of the plunger is accommodated in the pipetting cavity, and the thimble reciprocates in the up-down direction to drive the plunger to reciprocate in the pipetting cavity.

[0011] A sealing ring is arranged between the driving support and the pipetting cavity, the sealing ring is arranged around the plunger, the plunger can reciprocate in the up-down direction relative to the sealing ring, and the sealing ring is used for sealing the lower opening of the pipetting cavity.

[0012] The surface roughness Ra of the inner side surface of the pipetting cavity is greater than or equal to 6.4.

[0013] Optionally, the inner side of the pipetting cavity is provided with an internal thread structure.

[0014] Optionally, the inner side of the pipetting cavity is provided with a plurality of annular grooves arranged side by side in the up-down direction.

[0015] Optionally, the inner side of the pipetting cavity is provided with a plurality of pits.

[0016] Optionally, the outer side surface roughness Ra of the plunger is less than or equal to 0.1.

[0017] Optionally, a guide pin is included, the thimble is provided with a guide groove extending in the up-down direction, the driving support is provided with a pin hole, the guide pin is installed in the pin hole, the guide pin extends into the guide groove through the pin hole, and one end of the guide pin extending into the guide groove can reciprocate in the guide groove relative to the thimble in the up-down direction.

[0018] Optionally, the upper side of the sealing ring is provided with an O-ring.

[0019] Optionally, the pipetting cavity is provided with a liquid inlet and a liquid outlet, the liquid inlet is communicated with the pipetting cavity, and the liquid outlet is communicated with the pipetting cavity.

[0020] Optionally, the driving support is provided with a photoelectric sensor, and the photoelectric sensor is used for detecting position information of the thimble.

[0021] Optionally, the driving motor is a stepper motor.

[0022] The utility model discloses a high reliability pipette pump, the roughness Ra of the inner surface of pipette cavity is set to 6.4 and above, the roughness of the inner surface of pipette cavity is designed to be above 6.4, the space of accommodating residual solution and crystallization is increased, the crystal precipitated in the solution will be attached to the rough inner surface of pipette cavity in priority during the working process of pipette pump, the crystal precipitated in the solution grows in priority on the inner surface of pipette cavity, the probability of the crystal precipitated in the solution attaching to the plunger is reduced, the risk of the sealing ring being broken by a large number of precipitated crystals on the plunger is reduced, the use reliability of pipette pump is increased, and the use safety and service life of pipette pump are improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to make the technical problems, technical schemes and beneficial effects solved by the utility model clearer, the utility model will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and not to limit the utility model.

[0024] Figure 1 is the cross section schematic view of pipette pump in the first state in an embodiment of the utility model,

[0025] Figure 2 is Figure 1 the local enlarged view of A part in it,

[0026] Figure 3 is the cross section schematic view of pipette pump in the second state in an embodiment of the utility model.

[0027] The reference signs in the specification are as follows:

[0028] 10, drive motor, 20, drive support, 21, photoelectric sensor, 30, screw rod, 40, nut, 41, guide groove, 50, pipette cavity, 501, pipette cavity, 502, liquid inlet, 503, liquid outlet, 60, plunger, 70, sealing ring, 71, O ring, 80, guide pin. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical schemes and beneficial effects solved by the utility model clearer, the utility model will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and not to limit the utility model.

[0030] In the description of the utility model, it is necessary to understand that the orientation or positional relationship indicated by the terms "longitudinal", "radial", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is the orientation or positional relationship based on the drawings shown, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model. In the description of the utility model, unless otherwise specified, the meaning of "a plurality of" is two or more than two.

[0031] In the description of the utility model, it should be explained that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0032] One embodiment of the utility model provides a kind of high reliability pipette pump, including drive motor 10, drive bracket 20, screw rod 30, nut 40, pipette cavity 50 and plunger 60. As shown in Figure 1 Drive motor 10, drive bracket 20 and pipette cavity 50 are sequentially arranged from bottom to top.

[0033] Screw rod 30 and nut 40 are arranged in drive bracket 20, and nut 40 can reciprocate relative to drive bracket 20 in up-down direction. As shown in Figure 1 Drive bracket 20 is provided with containing cavity, and nut 40 and screw rod 30 are arranged in the interior of drive bracket 20, i.e. in the containing cavity of drive bracket 20;Nut 40 can reciprocate relative to drive bracket 20 in up-down direction. Wherein, screw rod 30 is threadedly connected with nut 40, and drive motor 10 is used to drive screw rod 30 to rotate around the axial direction of screw rod 30, and the rotation of screw rod 30 can drive nut 40 to reciprocate in up-down direction.

[0034] The driving motor 10 is a driving mechanism of the pipetting pump. During operation, the control system sends a control signal to the driver of the driving motor 10. The driver of the driving motor 10 processes and amplifies the control signal, and then transmits the amplified control signal to the driving motor 10, so that the driving motor 10 starts to work. The output shaft of the driving motor 10 is connected to the lead screw 30. When the driving motor 10 starts to work, the lead screw 30 connected to the output shaft of the driving motor 10 rotates along its axial direction. The lead screw 30 is threadedly connected to the nut 40. The axial rotation of the lead screw 30 drives the nut 40 to move in the up-down direction. The axial rotation of the output shaft of the driving motor 10 and the lead screw 30 is converted into the linear motion of the nut 40 in the up-down direction, so as to realize the subsequent driving process.

[0035] To ensure the stability of the overall structure, in some embodiments, the pipetting cavity 50 and the driving support 20 are fixedly connected, and the moving cavity 50 is located above the driving support 20, i.e., the lower end of the moving cavity 50 is fixedly connected to the upper end of the driving support 20. Here, the fixed connection can be detachable, such as buckles, or one-time fixed, such as bonding or welding. The pipetting cavity 50 is provided with a pipetting cavity 501 extending in the up-down direction. One end of the plunger 60 is fixedly connected to the nut 40, and the other end of the plunger 60 extends into the pipetting cavity 501, and at least part of the plunger 60 is accommodated in the pipetting cavity 501. In this way, the reciprocating movement of the nut 40 in the up-down direction can drive the plunger 60 to reciprocate in the pipetting cavity 501.

[0036] As shown in Figure 1 , Figure 2 and Figure 3 , the movement of the nut 40 in the up-down direction can drive the plunger 60 to move in the up-down direction. The up-down movement of the plunger 60 can increase the internal pressure in the pipetting cavity 501 or form a negative pressure, so as to realize the actions of discharging and sucking liquid.

[0037] In some embodiments, the plunger 60 is a cylindrical plunger 60, and the pipetting cavity 501 is a cylindrical space extending in the up-down direction.

[0038] As shown in Figure 1 , in some embodiments, the upper end of the nut 40 is provided with a mounting hole of the plunger 60, one end of the plunger 60 is connected in the mounting hole, and the other end extends into the pipetting cavity 501. More specifically, the mounting hole of the plunger 60 is a cylindrical mounting hole capable of being connected with the end of the plunger 60. In this way, the pipetting cavity 501, the plunger 60 and the mounting hole of the plunger 60 can be coaxially arranged in the up-down direction.

[0039] To ensure the sealing of the pipetting cavity 501, prevent liquid leakage, a sealing ring 70 is arranged between the driving support 20 and the pipetting cavity 50, the sealing ring 70 is arranged around the plunger 60, the plunger 60 can reciprocate relative to the sealing ring 70 in the up-down direction, and the sealing ring 70 is used for sealing and isolating the lower opening of the pipetting cavity 501, that is, the opening of the pipetting cavity 501 close to the driving support 20.

[0040] As shown in Figure 1 and Figure 2 , the upper end of the driving support 20 and the contact surface of the pipetting cavity 50 are provided with a sealing ring 70 mounting platform, which is designed around the pipetting cavity 501; more specifically, the platform is located at the lower opening of the pipetting cavity 501 and the upper opening of the mounting hole of the upper plunger 60 of the driving support 20. The sealing ring 70 is mounted at the mounting platform, as shown in Figure 1 and Figure 3 , the lowermost end of the plunger 60 is fixedly connected with the nut 40, and the plunger 60 is driven by the nut 40 to move up and down; the plunger sequentially passes through the mounting hole of the plunger 60, the through hole of the driving support 20, the center hole of the sealing ring 70, the lower opening of the pipetting cavity 501 and extends into the pipetting cavity 501 from bottom to top. The sealing ring 70 is mounted in close contact with the outer side of the plunger 60, and closes the lower end opening of the pipetting cavity 501, so as to realize the sealing of the pipetting cavity 501, and the plunger 60 can slide up and down relative to the sealing ring 70.

[0041] In the high-reliability pipetting pump provided by the utility model, the plunger 60 moves up and down in close contact with the sealing ring 70, once the plunger 60 grows crystals, the close up-and-down sliding action of the plunger 60 and the sealing ring 70 will cause the crystals on the plunger 60 to scratch the sealing ring 70, so that the sealing effect of the plunger 60 on the pipetting cavity 501 is lost, liquid leakage is caused, and the use safety and service life of the pipetting pump are affected.

[0042] In order to solve the problem that the plunger 60 grows crystals and scratches the sealing ring 70, causing liquid leakage, in the utility model, the surface roughness of the inner side of the pipetting cavity 501 is designed as Ra≥6.4. By forming a rough surface on the inner side of the pipetting cavity 501, and the roughness Ra≥6.4, the crystals precipitated in the solution during the use of the pipetting pump will preferentially adhere to the inner surface of the pipetting cavity 501 with rough surface, reducing the probability of the solution precipitated crystals adhering to the plunger 60, so that the surface of the plunger 60 can be smooth, and the crystallization on the surface of the plunger 60 can be reduced; during use, the plunger 60 is not easy to scratch the sealing ring 70 due to growth of crystals, the use reliability of the pipetting pump is increased, and the safety and service life of the pipetting pump are improved.

[0043] The working process of the high-reliability pipetting pump provided by the utility model is briefly described as follows:

[0044] Figure 1The diagram shows the first state of the pipette pump, also known as the reset state. In this first state, the nut 40 is at the top, the plunger 60 has the largest volume within the pipette chamber 501, and the free volume of the pipette chamber 501 is the smallest. Figure 3 As shown, this is the second state of the pipette pump, which can also be called the suction maintenance state. In the second state, the nut 40 is at the bottom, the volume of the plunger 60 contained in the pipette chamber 501 is the smallest, and the free volume of the pipette chamber 501 is the largest.

[0045] During the aspiration process, the pipette pump gradually transitions from the first state (i.e., the reset state) to the second state. The nut 40 moves from the top to the bottom, and the plunger 60 moves downward. The volume of the plunger 60 within the pipette chamber 501 gradually decreases, while the free volume of the pipette chamber 501 increases. During this process, a negative pressure is created inside the pipette chamber 501 due to the movement of the plunger 60, thus achieving aspiration. When the pipette pump is fully in the second state, the aspiration process ends, and pipetting begins. During pipetting, the pipette pump can be maintained in the second state.

[0046] During the drainage process, the pipette pump gradually transitions from the second state to the first state (i.e., the reset state). The nut 40 moves from the bottom to the top, and the plunger 60 moves upward. The volume of the plunger 60 within the pipette chamber 501 gradually increases, while the free volume of the pipette chamber 501 decreases. During this process, due to the movement of the plunger 60, the internal pressure of the pipette chamber 501 increases, causing the liquid inside to be discharged under the influence of internal pressure. The drainage process ends when the pipette pump is fully in the first state.

[0047] In some embodiments, before the pipette pump starts aspirating liquid, it needs to be adjusted to the first state, i.e., the reset state.

[0048] To facilitate automated production, such as Figure 1 As shown, in one embodiment of this utility model, the inner side of the pipetting cavity 501 is provided with an internal thread structure. That is, the inner wall of the pipetting cavity 501 is machined into an internal thread structure to increase the surface roughness of the inner side of the pipetting cavity 501, so that the surface roughness Ra of the inner side of the pipetting cavity 501 is ≥6.4.

[0049] As a preferred embodiment of this utility model, the internal thread structure, in addition to the internal thread structure, can be used in other embodiments of this utility model to provide multiple annular grooves arranged side by side along the vertical direction on the inner side of the pipetting cavity 501. It is understood that both the annular grooves and the internal thread structure aim to create a structure with high surface roughness on the inner wall; the internal thread structure is equivalent to a continuous groove structure, which is easier to process and more efficient in production; while the annular grooves, unlike the internal thread structure, are discontinuous, requiring a workpiece with an expandable outer diameter during production.

[0050] In some other embodiments of the utility model, a plurality of pits can be arranged inside the pipetting cavity 501.

[0051] In order to greatly reduce the probability of the crystal growing outside the plunger 60 when the solution is crystallized, and increase the probability of the crystal growing on the inner wall of the pipetting cavity 501, in an embodiment of the utility model, the outer surface roughness Ra of the plunger 60 is set to be not greater than 0.1; in this way, by combining the more smooth plunger 60 with the more rough inner wall of the pipetting cavity 501, the solution crystal is allowed to grow preferentially on the inner wall of the pipetting cavity 501 which is more rough, the probability of the plunger 60 surface growing the solution crystal is ensured to be smaller, the possibility of scratching the sealing ring 70 is further reduced, and the reliability and safety are improved.

[0052] In an embodiment of the utility model, the material of the plunger 60 can use ceramic material or corrosion-resistant 316 stainless steel material, and the corrosion-resistant 316 stainless steel material is preferred. More specifically, the plunger 60 adopts the corrosion-resistant 316 stainless steel material, and the surface of the plunger 60 is sprayed with PTFE (polytetrafluoroethylene); the PTFE (polytetrafluoroethylene) has excellent acid and alkali resistance, is almost insoluble in any solvent, and the friction coefficient of the PTFE (polytetrafluoroethylene) is extremely low, so that the outer surface roughness of the plunger 60 is ensured to be less than 0.1, and the friction generated when the plunger moves can be better reduced; since the fluorine-containing material has a low surface energy, and the low surface energy shows strong hydrophobicity (similar to lotus leaves), the adhesion of the solution to the surface is very low, so that the adhesion can be greatly reduced, the crystal is prevented from precipitating on the surface of the plunger 60, and the reliability and service life of the pipetting pump are improved.

[0053] As shown in Figure 1 In order to ensure that the nut 40 can move more stably in the up-down direction, in an embodiment of the utility model, the nut 40 is provided with a guide groove 41 extending in the up-down direction, the driving bracket 20 is provided with a pin hole, the guide pin 80 is installed in the pin hole, and one end of the guide pin 80 penetrating through the pin hole extends into the guide groove 41. The design of the guide groove 41 and the guide pin 80 can effectively fix the angle of the nut 40 in the axial direction, prevent the nut 40 from rotating in the axial direction under the driving of the lead screw 30, and make the action of the nut 40 more stable.

[0054] In this embodiment, the guide pin 80 is inserted into the guide groove 41 to prevent the nut 40 from rotating in the axial direction; at the same time, the guide pin 80 can reciprocate in the up-down direction in the guide groove 41, as the movement track of the nut 40, guide the up-down movement of the nut 40 and limit the axial angle at the same time.

[0055] In order to further improve the sealing strength of the lower side opening of the pipetting cavity 501, in an embodiment of the present application, an O-ring 71 is arranged on the side of the sealing ring 70 close to the pipetting cavity 50, and the sealing performance is further improved by the O-ring 71. As shown in Figure 2 , the O-ring 71 is coaxially arranged with the sealing ring 70 and is arranged above the sealing ring 70, i.e. on the side close to the pipetting cavity 50. The O-ring 71 is also arranged around the plunger 60, and the plunger 60 can slide up and down along the inner side of the O-ring 71.

[0056] As shown in Figure 2 , in an embodiment of the present application, in order to cooperate with the application scene of the pipetting pump, a liquid inlet 502 and a liquid outlet 503 are arranged on the pipetting cavity 50. The liquid inlet 502 is communicated with the pipetting cavity 501, and the liquid outlet 503 is communicated with the pipetting cavity 501. More specifically, the liquid inlet 502 and the liquid outlet 503 are both provided with a switch valve. When liquid is sucked, the liquid inlet 502 is opened and the liquid outlet 503 is closed. When liquid is discharged, the liquid inlet 502 is closed and the liquid outlet 503 is opened.

[0057] In other application scenes, according to the needs, only one opening can be arranged, i.e. the liquid inlet and the liquid outlet are realized through one opening.

[0058] In an embodiment of the present application, a photoelectric sensor 21 is arranged on the driving support 20, and the photoelectric sensor 21 is used to detect the position information of the nut 40. As shown in Figure 1 , in an embodiment of the present application, the photoelectric sensor 21 is arranged on the upper side of the driving support 20 and is used to detect the position information of the nut 40. More specifically, the photoelectric sensor 21 detects the position information of the nut 40 when the pipetting pump is in the first state (i.e. the nut 40 is located at the uppermost end), and is used to judge whether the nut 40 is reset after pipetting and whether the pipetting pump returns to the reset state (i.e. the first state). Generally, the photoelectric sensor 21 adopts a light source to detect the position information, and the nut 40 is provided with a baffle that can block the light source. When the pipetting pump is in the reset state (the first state), the baffle of the nut 40 blocks the light source, and the photoelectric sensor 21 collects the position signal and identifies that the pipetting pump is successfully reset.

[0059] In some embodiments, considering the control accuracy requirement, a stepper motor can be selected as the driving motor 10 to meet the high-precision control requirement. Of course, in some scenes with general control accuracy requirement, other driving motors 10 can also be used.

[0060] In Figure 1 and Figure 2In the embodiment shown by the utility model, the step motor is selected as the driving motor 10, the control system of the pipette pump sends a pulse signal to the step motor driver, the step motor driver processes and amplifies the pulse signal, and then transmits the amplified signal to the step motor.

[0061] The above-described embodiments are only used to illustrate the technical solutions of the utility model, rather than limit them; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model, and should be included in the protection scope of the utility model.

Claims

1. A high-reliability pipetting pump, comprising a driving motor, a driving support, a screw rod, a screw nut, a pipetting cavity and a plunger, the screw rod and the screw nut are arranged on the driving support, the driving motor is used to drive the screw rod to rotate around the axial direction of the screw rod; the screw rod is threadedly connected with the screw nut, the screw nut can reciprocate along the up-down direction relative to the driving support, and the rotation of the screw rod can drive the screw nut to reciprocate along the up-down direction; the pipetting cavity is fixedly connected with the driving support, the pipetting cavity is located above the screw nut, the pipetting cavity is provided with a pipetting cavity extending along the up-down direction, one end of the plunger is fixedly connected with the screw nut, the other end of the plunger extends into the pipetting cavity, at least part of the plunger is accommodated in the pipetting cavity, and the screw nut drives the plunger to reciprocate in the pipetting cavity along the up-down direction; a sealing ring is arranged between the driving support and the pipetting cavity, the sealing ring surrounds the plunger, the plunger can reciprocate along the up-down direction relative to the sealing ring, and the sealing ring is used to seal the lower opening of the pipetting cavity; characterized in that the surface roughness Ra of the inner side surface of the pipetting cavity is greater than or equal to 6.4; the plunger is a ceramic plunger; or the plunger is a stainless steel plunger.

2. The high-reliability pipetting pump of claim 1, wherein, An internal thread structure is arranged on the inner side of the pipetting cavity.

3. The high-reliability pipette pump of claim 1, wherein, A plurality of annular grooves are arranged side by side along the up-down direction on the inner side of the pipetting cavity.

4. The high-reliability pipette pump of claim 1, wherein, A plurality of pits are arranged on the inner side of the pipetting cavity.

5. The high-reliability pipetting pump according to any one of claims 1 to 4, characterized in that The outer side surface roughness Ra of the plunger is less than or equal to 0.

1.

6. The high reliability pipette pump of claim 1, wherein, A guide pin is arranged, the screw nut is provided with a guide groove extending along the up-down direction, the driving support is provided with a pin hole, the guide pin is installed in the pin hole, the guide pin extends into the guide groove through the pin hole, and one end of the guide pin extending into the guide groove can reciprocate in the guide groove along the up-down direction relative to the screw nut.

7. The high reliability pipette pump of claim 1, wherein, An O-ring is arranged on the upper side of the sealing ring.

8. The high reliability pipette pump of claim 1, wherein, A liquid inlet and a liquid outlet are arranged on the pipetting cavity, the liquid inlet is communicated with the pipetting cavity, and the liquid outlet is communicated with the pipetting cavity.

9. The high reliability pipette pump of claim 1, wherein, The driving support is provided with a photoelectric sensor, and the photoelectric sensor is used to detect the position information of the screw nut.

10. The high reliability pipette pump of claim 1, wherein, The driving motor is a step motor.

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