A quantitative negative pressure pipetting device

Abstract

The utility model discloses a kind of quantitative negative pressure pipetting devices, it is related to cell laboratory equipment technical field, including bottle body and bottle cap, the bottle cap slidingly connected with connecting rod and is connected with suction duct below, the bottom of the connecting rod is connected with piston, the piston is sealed sliding in the suction duct, the suction duct is equipped with limit ring in the stroke start-stop point of the piston, the suction duct side is equipped with the liquid outlet pipe of one-way liquid outlet, the suction duct one-way suction liquid upwardly.The utility model provides a kind of quantitative negative pressure pipetting device, quantitative high-efficiency accurate, can be operated by single hand, save time and effort.

Description

Technical Field

[0001] This utility model relates to the field of cell laboratory equipment technology, specifically to a quantitative negative pressure pipetting device. Background Technology

[0002] In cell experiments, washing cells is a frequent and crucial step, typically requiring multiple cycles of "adding water and mixing - centrifugation - discarding supernatant." Adding a quantitative amount of washing solution (such as water or buffer) to the cell pellet and mixing thoroughly is fundamental to ensuring effective washing. Currently, this water-adding and mixing step often relies on manual syringe injection. However, using syringes has significant drawbacks: firstly, the process is time-consuming and laborious, especially inefficient when performing multiple washes; secondly, manual injection makes it difficult to guarantee the accuracy and consistency of each liquid addition, affecting the reliability of experimental results; thirdly, standard syringes usually require coordinated operation with both hands (one hand holding the syringe barrel, the other pushing and pulling the plunger), which is extremely inconvenient in scenarios requiring simultaneous processing of samples or other instruments, and cannot achieve rapid single-handed operation. Furthermore, an ideal water-adding and mixing process requires adding the liquid at a certain flow rate or with a certain impact force (e.g., "pressing to draw water, spraying to add water") to effectively resuspend the cell pellet, an effect that ordinary syringes cannot easily achieve. Therefore, there is an urgent need for a semi-automatic quantitative liquid dispensing device for the cell washing and water addition step, which can overcome the above-mentioned defects of syringes and realize rapid, accurate and efficient quantitative liquid dispensing and mixing operations with one hand, thereby significantly improving the efficiency and standardization of the experimental process. Utility Model Content

[0003] Technical problem to be solved by the utility model

[0004] The technical problem to be solved by this utility model is to provide a quantitative negative pressure pipetting device that is efficient and accurate in quantitative measurement, can be operated with one hand, and saves time and effort.

[0005] Technical solution

[0006] To solve the above problems, the technical solution provided by this utility model is as follows:

[0007] A quantitative negative pressure pipetting device includes a bottle body and a bottle cap. A connecting rod is slidably connected to the bottle cap and a suction tube is connected below it. A piston is connected to the bottom of the connecting rod. The piston slides in a sealed manner within the suction tube. Limiting rings are provided at the beginning and end points of the piston's stroke within the suction tube. A one-way liquid outlet tube is provided on the side of the suction tube, and the suction tube draws liquid upwards in one direction.

[0008] The bottle / cap provides the main support, and the user drives the piston to move within the liquid suction tube by lifting or pressing a lever with one hand from within the cap. A limiting ring precisely controls the piston stroke, ensuring a constant volume of negative pressure chamber each time, achieving accurate metering. When the user lifts the lever (piston moves upward), the one-way suction valve at the bottom of the suction tube opens, and the liquid in the bottle is automatically and metered into the tube; when the user presses the lever down (piston moves downward), the suction valve closes, the liquid in the tube is pressurized, and can only be discharged through the outlet tube with a one-way outlet valve, achieving efficient mixing.

[0009] Optionally, the bottom of the suction pipe is provided with a main channel closing ball, the lower part of the main channel closing ball is sealed with a main channel closing ring, and the upper part of the main channel closing ball is provided with a main channel blocking filter. The main channel closing ball can move between the main channel closing ring and the main channel blocking filter to form a passage.

[0010] This structure forms a precision one-way suction valve located at the bottom of the suction pipe. Its core is the main closure ball, which acts like a movable gate. A main closure ring at the bottom of the suction pipe serves as a precision valve seat for the ball. When the piston moves upward, generating negative pressure, the suction pulls the closure ball upward, causing it to leave the closure ring and opening a passage between them, allowing liquid to be drawn into the pipe. To prevent the ball from being sucked too high and becoming stuck or malfunctioning, a main closure filter screen is installed above it. This screen limits the ball's upward movement, ensuring it always moves within a controllable range. Simultaneously, this filter screen also plays a crucial filtering role, preventing larger particles of impurities in the liquid from entering the suction pipe and protecting the device from blockage. When the suction disappears (the piston stops moving upward or begins to move downward), the ball falls naturally under gravity or pressure, tightly fitting against the main closure ring to form a reliable seal, closing the passage and effectively preventing liquid backflow or leakage from the bottom. Therefore, this structure, which consists of a closed ball, a closed loop, and a blocking filter working together, precisely achieves the function of "one-way upward liquid suction" of the liquid suction pipe: it only conducts upward liquid suction when there is negative pressure, and is tightly closed in other states.

[0011] Optionally, a suction tube is connected to the bottom of the suction pipe.

[0012] The suction tube, serving as the rigid main channel for liquid transfer, has its bottom as the inlet for the liquid entering the device. To overcome the limitations of rigid tubing in terms of operational flexibility and ensure thorough suction, a flexible suction tube is sealed to the bottom of the suction tube. This flexible tube extends the reach of the suction inlet, allowing it to easily reach every corner of the bottle's bottom, ensuring that the liquid inside (such as cleaning fluid) is completely sucked up, avoiding waste. More importantly, the flexibility of the tube greatly enhances the device's operational flexibility. Users (especially when operating with one hand) can freely tilt or move the device body (bottle section), and the suction tube will bend accordingly, eliminating the need to strictly maintain the device body vertically or precisely align it with the bottle bottom. This significantly simplifies operation and improves efficiency.

[0013] Optionally, the main channel closure ring is installed on the main channel closure base, and the main channel closure base is fixed to the inner wall of the liquid suction pipe.

[0014] To ensure the closure ring is securely and accurately positioned within the pipe and maintains a reliable seal against repeated impacts from the ball and fluid pressure, it is not directly fixed to the pipe wall. Instead, it is first mounted on a specially designed main closure base. This base serves as a support platform and mounting base for the closure ring, supporting and securing it. Then, the entire base, along with the closure ring mounted on it, is securely attached to the inner wall of the suction pipe using robust connection methods (such as threads, snaps, or adhesives). This hierarchical "closure ring-base-pipe" design maximizes the rigidity and positional stability of the valve seat assembly, providing a solid and reliable sealing surface for the closure ball. This ensures the efficient, accurate, and long-term operation of the one-way valve (which opens only when the piston moves upward to generate negative pressure, and closes tightly in other states).

[0015] Optionally, the outlet pipe is arranged obliquely upward, and a branch closure ball is provided inside it. The lower part of the branch closure ball is sealed and connected to a branch closure ring, and a branch blocking filter is provided above the branch closure ball. The branch closure ball can move between the branch closure ring and the branch blocking filter to form a passage.

[0016] Inside the upward-sloping outlet pipe, a branch one-way outlet valve is designed, similar in principle to the main suction valve but with the opposite function. The core of this valve is the branch closing ball, which moves up and down within a specific space to control the opening and closing of the channel. The branch closing ring is fixed inside the outlet pipe, providing a precise valve seat sealing surface for the closing ball. When the piston presses down to pressurize the liquid in the suction pipe, the liquid pressure pushes the branch closing ball away from the branch closing ring, thus opening the passage and allowing the pressurized liquid to be ejected along the upward-sloping outlet pipe; this directional jet effectively impacts and resuspends cell sediment at the bottom of the container. To prevent the ball from being ejected too high and failing, a branch blocking filter is installed above it, strictly limiting the ball's upward movement; simultaneously, this filter intercepts any small particulate impurities that may be present in the liquid, preventing blockage of the small outlet and ensuring smooth and reliable spraying. When the piston pressure disappears, the branch closing ball automatically falls under the influence of gravity, tightly fitting against the branch closing ring to form a reliable seal, closing the passage and effectively preventing liquid leakage in non-working states and backflow of external contaminants. The upward angle of the outlet pipe not only optimizes the direction of the jet water impacting the sediment but also utilizes gravity to assist the closing ball in settling and sealing under non-pressurized conditions, enhancing the reliability of the check valve.

[0017] Optionally, the end of the outlet pipe is provided with a horizontal bend, and the horizontal bend is threaded and threadedly connected to an external pipe.

[0018] Threads are machined into this horizontal bend. These threads provide a standardized, reliable, and detachable connection interface. Through this threaded interface, users can thread-connect various sizes of external pipes (such as rigid pipes or flexible pipes of different lengths). The horizontal bend facilitates the connection of external pipes.

[0019] Optionally, the bottle cap is provided with a sliding cavity and a limiting rack that slides within the sliding cavity. The limiting rack is in limiting contact with both ends of the sliding cavity. The connecting rod has teeth on its side that mesh with a large gear. A small gear is coaxially fixed to the large gear, and the small gear meshes with the limiting rack.

[0020] The high precision (small displacement, low error) of the hard limit at both ends of the sliding cavity is transmitted and amplified to the connecting rod stroke through the gear ratio, which greatly reduces the error of the end position of the connecting rod stroke. This accurately sets the start and end positions of the piston in the suction tube, ensuring a high degree of consistency and accuracy in the volume of liquid suctioned and discharged each time, and further solving the problem of insufficient precision of manually operated syringes.

[0021] Optionally, the bottle cap is provided with guide openings on both sides of the connecting rod.

[0022] The symmetrically distributed guide ports fit tightly against the two side walls of the connecting rod, like a precise linear guide, strongly constraining the degree of freedom of the connecting rod's motion, so that it can only perform strict linear reciprocating motion along the preset vertical axis.

[0023] Beneficial effects

[0024] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0025] In the technical solution provided by this utility model, the piston driven by the connecting rod runs in the liquid suction pipe. The limiting ring set at the start and end points of its stroke works in conjunction with the gear limiting mechanism to double ensure the accuracy and consistency of the liquid volume suction and discharge. The main closed ball, closed ring and blocking filter screen at the bottom of the liquid suction pipe form a one-way liquid suction valve to realize "automatic quantitative water suction upon release", and the filter screen intercepts impurities to prevent clogging. The liquid outlet pipe set at an angle upward forms a one-way liquid outlet valve through the branch closed ball, closed ring and blocking filter screen to realize "press-directed spraying". Its angle optimizes the water flow impact effect, and the threaded design of the horizontal bending section supports the detachable external pipe, extends the spray point and adapts to various experimental scenarios. The end liquid suction hose improves the degree of freedom of operation through flexibility to ensure that the liquid in the bottle is completely sucked out. Attached Figure Description

[0026] Figure 1 A schematic cross-sectional view of a quantitative negative pressure pipetting device proposed for an embodiment of this utility model;

[0027] Figure 2 A partial cross-sectional view of a quantitative negative pressure pipetting device proposed for an embodiment of this utility model;

[0028] Figure 3 A partial cross-sectional view of section B of a quantitative negative pressure pipetting device proposed for an embodiment of this utility model;

[0029] Figure 4 A cross-sectional schematic diagram of the bottle cap of a quantitative negative pressure pipetting device proposed for an embodiment of this utility model;

[0030] 1. Bottle body; 101. Dispensing port; 2. Bottle cap; 201. Guide port; 3. Press handle; 4. Connecting rod; 5. Suction pipe; 6. Piston; 7. Limiting ring; 8. Main channel closing ball; 9. Dispensing pipe; 901. Horizontal bend section; 10. External connecting pipe; 11. Suction hose; 12. Liquid; 13. Main channel closing base; 14. Main channel closing ring; 15. Main channel blocking filter; 16. Branch channel closing base; 17. Branch channel closing ring; 18. Branch channel blocking filter; 19. Large gear; 20. Small gear; 21. Sliding cavity; 22. Limiting rack; 23. Branch channel closing ball. Detailed Implementation

[0031] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0032] Example

[0033] Combined with appendix Figure 1 A quantitative negative pressure pipetting device includes a bottle body 1 and a cap 2. The bottle body 1 and the cap 2 constitute the main body of the device, providing stable support and a liquid container 12 (water or buffer solution), which is easy to hold and operate. The axial edges of the bottle body 1 and the cap 2 are screwed together to facilitate the downward installation of the dispensing tube 9.

[0034] A connecting rod 4 is slidably connected to the bottle cap 2, and a liquid suction tube 5 is connected below it. A piston 6 is connected to the bottom of the connecting rod 4. The piston 6 slides and seals within the liquid suction tube 5, which is the core channel for the transfer of liquid 12. The piston 6 slides and seals within itself, forming a negative pressure chamber. The connecting rod 4 slides within the bottle cap 2, and the user can drive the piston 6 to move within the liquid suction tube 5 by lifting or pressing the connecting rod 4 with one hand. This completely replaces the cumbersome mode of traditional syringes that require two hands to operate, realizing the key single-handed operation function and significantly improving the ease of operation.

[0035] Limiting rings 7 are installed at both the start and end points of the piston 6's stroke within the suction pipe 5. These limiting rings 7 strictly limit the maximum displacement of the piston 6. This design ensures that the cavity volume formed by each piston 6 movement remains constant, fundamentally solving the problems of poor accuracy and low consistency in manual injection, and achieving precise and reliable quantitative liquid delivery.

[0036] The suction pipe 5 has a one-way outlet pipe 9 on its side. The outlet pipe 9 (with a one-way valve) is located on the side of the suction pipe 5, and its one-way outlet characteristic (like a duckbill valve or umbrella valve) is key to achieving the "spraying and adding water" mixing effect. When the user presses down the connecting rod 4 to drive the piston 6, the piston 6 compresses the liquid 12 in the suction pipe 5, forcing the liquid 12 to exit only through the outlet pipe 9, thus limiting its path.

[0037] The suction pipe 5 draws liquid upwards in one direction only. This suction pipe 5 (with a one-way valve) is located at the bottom (or the port immersed in liquid 12). Its one-way upward characteristic (like a check valve) allows the liquid 12 in the bottle 1 to be smoothly and automatically drawn into the suction pipe 5 when the user lifts the connecting rod 4 to drive the piston 6 upwards (the valve closes to prevent backflow when the piston 6 moves downwards). This structure, in conjunction with the piston 6 and the limiting ring 7, achieves a semi-automatic cycle of "pressing (downward) to spray liquid, releasing (upward) to automatically draw quantitative water," eliminating the need for repeated manual suction and switching like with a syringe. This greatly simplifies the operation, saves time and effort, and improves the efficiency of the entire washing process.

[0038] The bottom of the suction pipe 5 is provided with a main channel closing ball 8, the lower part of the main channel closing ball 8 is sealed with a main channel closing ring 14, and the upper part of the main channel closing ball 8 is provided with a main channel blocking filter 15. The main channel closing ball 8 can move between the main channel closing ring 14 and the main channel blocking filter 15 to form a passage.

[0039] Combined with appendix Figure 2 The main flow closing ball 8 is a sphere that moves up and down within a defined space under its own weight or the pressure of the liquid 12. Its positional changes control the opening and closing of the suction channel. When there is no suction action (the negative pressure generated by the upward movement of piston 6 disappears or positive pressure / gravity exists), the ball falls and rests on the main flow closing ring 14, forming a seal and preventing the liquid 12 from flowing back up or leaking down from the bottom of the suction pipe 5. When suction is needed (the upward movement of piston 6 generates negative pressure), the ball is lifted by the upward suction force and leaves the main flow closing ring 14, thus creating a gap (passage) between the ball and the closing ring, allowing the liquid 12 to be drawn into the suction pipe 5.

[0040] The main closure ring 14 is located at the bottom of the suction pipe 5, below the main closure ball 8. It provides a precise, sealable valve seat for the ball. When the main closure ball 8 falls, its conical or annular sealing surface fits tightly against the ball, blocking the flow of liquid 12 and ensuring that liquid 12 will not leak or backflow from the bottom when not in a suction state. This determines the final position of the ball when it falls, ensuring a sealing effect. The main closure filter 15 is located at the bottom of the suction pipe 5, above the main closure ball 8, and serves both as a physical barrier and a filter. When the piston 6 moves upward and generates suction, it prevents the main closure ball 8 from being sucked too high, preventing the ball from getting stuck above the pipe or falling out of its working position, ensuring that the ball always moves within its effective working range (i.e., between the closure ring and the filter). This is the core meaning of "blocking". Its mesh structure can filter out larger particulate impurities or sediments that may be present in the liquid 12 inside the bottle, preventing these impurities from entering the liquid suction pipe 5 and avoiding blockage of the pipe, piston 6, or liquid outlet 101, thus ensuring the long-term reliable operation of the device. This is the core meaning of "filter".

[0041] Passage opening (liquid suction): Piston 6 moves upward to generate negative pressure → suction overcomes the weight of the ball → the ball is sucked up and moves upward → the ball leaves the closed loop → the passage opens between the ball and the closed loop → liquid 12 is sucked into the suction pipe 5 from the bottom → the ball is finally blocked by the filter screen.

[0042] The passage is closed (sealed): Piston 6 stops moving upwards or downwards (negative pressure disappears) → The ball falls under the influence of gravity or the pressure of liquid 12 → The ball falls back and seals against the main passage closure ring 14 → The passage is completely closed → preventing backflow or leakage of liquid 12. Liquid 12 can only flow upwards under negative pressure (liquid suction) (the ball rises), while it cannot flow downwards under other conditions (positive pressure, gravity) (the ball falls and seals), perfectly realizing the functional requirement of "one-way upward liquid suction".

[0043] The bottom of the suction pipe 5 is connected to a suction hose 11. The hose houses a piston 6 that reciprocates to generate negative or positive pressure. It serves as the mounting carrier for one-way valves (such as the main closing ball 8, closing ring, or filter) and the outlet pipe 9, forming the main channel for the flow of liquid 12 within the device body. Its bottom is the inlet for liquid 12 into this main channel. This allows the suction inlet (the end of the hose) to flexibly penetrate deep into the bottom of the bottle 1, even to the edge or recess of the bottle 1, ensuring that the liquid 12 inside the bottle is completely sucked up, avoiding residue and waste. The flexibility of the hose allows users to freely adjust the angle and position of the device body (bottle 1 / cap 2) during operation (especially with one hand) without strictly aligning it with the bottle bottom or worrying about the rigid hose colliding with the bottle wall. This greatly enhances the convenience and fault tolerance of one-handed operation. The hose can more easily adapt to storage bottles (bottle 1) of different shapes or sizes, improving the versatility of the device. To a certain extent, it can buffer minor vibrations or positional changes during operation. Its connection to the bottom of the suction pipe 5 is typically designed as a sealed connection to ensure the airtightness of the liquid 12 transmission path. This sealing connection is usually achieved through methods such as plugging, screwing, or snap-fit. It ensures that the liquid 12 flows smoothly and leak-free from the hose into the suction pipe 5, making it a crucial link in the entire suction path. The connection point is located at the bottom of the suction pipe 5, conforming to the natural flow direction of the liquid 12 as it is drawn upwards from the bottle 1.

[0044] The main closure ring 14 is mounted on the main closure base 13, which is fixed to the inner wall of the suction pipe 5. The main closure base 13 provides a stable and precise mounting platform for relatively small or flexible closure rings. This ensures that the closure ring can be accurately positioned in the required location (usually the bottom) within the suction pipe 5. It secures the closure ring, preventing displacement, deformation, or detachment during operation (such as repeated impacts from the ball or the flow of liquid 12), thus ensuring the long-term stability of the sealing function. It also protects the closure ring from excessive impact to some extent.

[0045] Combined with appendix Figure 3The outlet pipe 9 is angled upwards and contains a branch closure ball 23. A branch closure ring 17 is sealed to the lower part of the branch closure ball 23, and a branch blocking filter 18 is located above the branch closure ball 23. The branch closure ball 23 can move between the branch closure ring 17 and the branch blocking filter 18 to form a passage. This invention designs a branch one-way outlet valve inside the angled outlet pipe 9, which is similar in principle to the main suction valve but has the opposite function. The core of this valve is the branch closure ball 23, which moves up and down within a specific space to control the opening and closing of the passage. The branch closure ring 17 is fixed inside the outlet pipe 9, providing a precise valve seat sealing surface for the closure ball. When the piston 6 presses down to pressurize the liquid 12 in the suction pipe 5, the pressure of the liquid 12 pushes up the branch closure ball 23, causing it to leave the branch closure ring 17, thereby opening the passage and allowing the pressurized liquid 12 to be ejected along the angled outlet pipe 9; this directional ejection effectively impacts and resuspends cell sediment at the bottom of the container. To prevent the ball from being propelled too high and malfunctioning, a branch blocking filter 18 is installed above it, strictly limiting the ball's upward movement. Simultaneously, this filter intercepts any small particulate impurities that may be present in the liquid 12, preventing blockage of the small outlet 101 and ensuring smooth and reliable spraying. When the pressure on the piston 6 is released, the branch closing ball 23 automatically falls under gravity, tightly fitting against the branch closing ring 17 to form a reliable seal, closing the passage and effectively preventing leakage of liquid 12 in non-operating conditions and backflow of external contaminants. The upward angle of the outlet pipe 9 not only optimizes the direction of the jet water impacting the sediment but also utilizes gravity to assist the closing ball in settling and sealing in non-pressurized conditions, enhancing the reliability of the one-way valve.

[0046] The end of the outlet pipe 9 is provided with a horizontal bend section 901, which is threaded and threadedly connected to the outer pipe 10. The horizontal bend section 901 provides a relatively straight and stable structural foundation for threading and connecting the outer pipe 10. The bend in the horizontal section makes it easier to machine the thread and provides operating space for tightening the outer pipe 10.

[0047] Combined with appendix Figure 4The bottle cap 2 has a sliding cavity 21 and a limiting rack 22 that slides within the sliding cavity 21. The limiting rack 22 is in limiting contact with both ends of the sliding cavity 21. The connecting rod 4 has teeth on its side that mesh with a large gear 19. The large gear 19 is coaxially fixed to a small gear 20, which meshes with the limiting rack 22. When the user moves the connecting rod 4 up or down, the teeth on the side of the connecting rod 4 drive the large gear 19 to rotate. The large gear 19, through coaxial fixing, synchronously drives the small gear 20 to rotate. The small gear 20 then meshes and drives the limiting rack 22 to slide linearly within the specially designed sliding cavity 21 inside the bottle cap 2. The rigid walls at both ends of the sliding cavity 21 provide a strict physical limitation (limiting contact) on the sliding stroke of the limiting rack 22, locking its maximum sliding range within a very small fixed value. Crucially, the small gear 20 has far fewer teeth than the large gear 19, forming a gear pair with a high reduction ratio. This means that the small, restricted stroke of the limiting rack 22 (determined by the length of the slide cavity 21) requires the pinion 20 to rotate multiple times, which in turn requires the large gear 19 (driven by the connecting rod 4) to rotate multiple times. Ultimately, this corresponds to the connecting rod 4 needing to move a longer, but precisely amplified, stroke. This design transmits and amplifies the high precision (small displacement, low error) of the hard-limited position at both ends of the slide cavity 21 to the stroke of the connecting rod 4 through the gear ratio, greatly reducing the error at the end position of the connecting rod 4's stroke. This allows for precise setting of the start and end positions of the piston 6 within the suction pipe 5, ensuring a high degree of consistency and accuracy in the volume of liquid 12 sucked and discharged each time.

[0048] The bottle cap 2 has guide ports 201 on both sides of the connecting rod 4. To ensure that the connecting rod 4 moves strictly up and down in a straight line during user push-pull operations, avoiding wobbling, deflection, or rotation, and thus ensuring the precise centering and straight movement of the piston 6 within the liquid suction pipe 5 (which is crucial for sealing, metering accuracy, and service life), this invention adopts a symmetrical guiding scheme in the structural design of the bottle cap 2. Specifically, the bottle cap 2 has dedicated guide ports 201 on both sides of the movement path of the connecting rod 4, either inside or at a specific location. These symmetrically distributed guide ports 201 fit tightly against the side walls of the connecting rod 4, acting like precise linear guides, strongly constraining the degree of freedom of the connecting rod 4, ensuring that it can only perform strictly linear reciprocating motion along a preset vertical axis.

[0049] The working principle is as follows:

[0050] When the user operates the linkage 4 up and down with one hand, the guide ports 201 on both sides of the linkage 4 forcibly constrain its linear motion. At the same time, the side teeth of the linkage 4 drive the large gear 19 to rotate, and the coaxially fixed small gear 20 drives the limiting rack 22 to slide in the slide cavity 21. The hard limit at both ends of the slide cavity 21 is precisely amplified by the gear transmission ratio to control the stroke of the piston 6, so that the piston 6 reciprocates precisely in the liquid suction pipe 5. When the linkage 4 is lifted, the piston 6 moves upward and generates negative pressure. The main channel closing ball 8 at the bottom of the liquid suction pipe 5 disengages from the closing ring and opens the passage. The liquid 12 flows through the liquid suction soft... The tube 11 draws in a quantitative amount of liquid, and the main channel blocking filter 15 limits the ball and filters impurities. When the connecting rod 4 is pressed down, the piston 6 moves downward to generate positive pressure, and the main channel closing ball 8 sits in the closing ring to seal the suction port. At the same time, the pressure pushes the branch closing ball 23 in the outlet tube 9 out of the branch closing ring 17. The liquid 12 is sprayed out in a direction through the horizontal bend section 901 of the outlet tube 9 set at an upward angle and the outer tube 10. The branch blocking filter 18 restricts the displacement of the ball and performs secondary filtration. This cycle realizes a semi-automatic cell washing process of "quantitative water intake - precise liquid spraying" under single-hand operation.

[0051] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A quantitative negative pressure pipetting device, characterized in that, The device includes a bottle body and a bottle cap. A connecting rod is slidably connected to the bottle cap and a liquid suction tube is connected below it. A piston is connected to the bottom of the connecting rod. The piston slides in a sealed manner within the liquid suction tube. Limiting rings are provided at the beginning and end points of the piston's stroke within the liquid suction tube. A one-way liquid outlet tube is provided on the side of the liquid suction tube, and the liquid suction tube draws liquid upwards in one direction. The bottle cap has a sliding cavity and a limiting rack that slides within the sliding cavity. The limiting rack is in limiting contact with both ends of the sliding cavity. The connecting rod has teeth on its side that mesh with a large gear. A small gear is coaxially fixed to the large gear and meshes with the limiting rack.

2. The quantitative negative pressure pipetting device according to claim 1, characterized in that, The bottom of the liquid suction pipe is provided with a main channel closing ball, the lower part of which is sealed with a main channel closing ring, and the upper part of the main channel closing ball is provided with a main channel blocking filter. The main channel closing ball can move between the main channel closing ring and the main channel blocking filter to form a passage.

3. The quantitative negative pressure pipetting device according to claim 2, characterized in that, The bottom of the suction pipe is connected to a suction hose.

4. A quantitative negative pressure pipetting device according to claim 2, characterized in that, The main channel closure ring is installed on the main channel closure base, and the main channel closure base is fixed to the inner wall of the liquid suction pipe.

5. A quantitative negative pressure pipetting device according to claim 1, characterized in that, The liquid outlet pipe is set at an angle upward and has a branch closure ball inside. The lower part of the branch closure ball is sealed and connected to a branch closure ring. A branch blocking filter is provided above the branch closure ball. The branch closure ball can move between the branch closure ring and the branch blocking filter to form a passage.

6. A quantitative negative pressure pipetting device according to claim 5, characterized in that, The end of the liquid outlet pipe is provided with a horizontal bend section, and the horizontal bend section is threaded and threadedly connected to an external pipe.

7. A quantitative negative pressure pipetting device according to claim 1, characterized in that, The bottle cap is provided with guide openings on both sides of the connecting rod.

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