A high-safety pipette pump

Abstract

The present invention discloses a high-safety pipette pump, comprising a driving motor, a driving bracket, a screw rod, a nut, a pipette cavity and a plunger, wherein an upwardly opening liquid accumulation groove is provided at the upper end of the nut, the liquid accumulation groove is located below the sealing ring, and the downward projection of the contact point between the sealing ring and the plunger is located in the upper opening of the liquid accumulation groove, so as to ensure that when leakage occurs at the contact point between the sealing ring and the plunger, the liquid flows into the liquid accumulation groove, and the liquid is prevented from flowing out, thereby improving the safety of use; at the same time, a liquid level sensor is provided on the driving bracket to detect the liquid level height of the leaked liquid in the liquid accumulation groove, so as to monitor the leakage situation in time and give an alarm, so as to remind the user to deal with the leakage incident or replace the relevant mechanism or even replace the pipette pump, thereby improving the safety of use of the pipette pump.

Description

Technical Field

[0001] The present invention relates to the field of automated medical treatment, and in particular to a high-safety liquid transfer pump. Background Art

[0002] High-precision pipette pumps are widely used in automated medical instruments for precise quantitative absorption and discharge of liquids. High-precision pipette pumps are usually driven by stepper motors. When the stepper motor driver receives the pulse signal emitted by the controller, it drives the stepper motor to rotate the corresponding angle in the set direction. Then, through the coordinated action of the screw rod and the nut, the rotary motion is converted into linear motion, causing the plunger to move up and down in the cavity to change the volume to achieve the purpose of aspirating or discharging liquid.

[0003] At present, the plunger in the industry is generally made of ceramic materials with good reagent resistance. Ceramic materials are easy to form, have high hardness, and can be made very smooth on the surface to facilitate sealing. The sealing ring will be made of ultra-high molecular polyethylene (polymer material) with extremely low friction coefficient (which can greatly reduce friction) and good corrosion resistance.

[0004] Existing pipette pumps can achieve microliter accuracy, but safety issues remain within the industry. Most pipette pumps operate with solutions that easily precipitate crystals. Over time, these crystals can adhere to the ceramic plunger. As the crystals grow, the hardened crystals can follow the plunger's upward and downward motion, potentially breaking the seal and causing leakage. The leaked medium is often corrosive and can severely damage the device's internal circuitry, leading to serious consequences.

[0005] In traditional pipette pump solutions, when leakage occurs at the contact point between the sealing ring and the plunger, the liquid will flow in an undirected manner to other locations of the pipette pump, or even flow out of the pipette pump; this will cause the leaked liquid to corrode the pipette pump, causing damage to the pipette pump. Liquid leaking out of the pipette pump will cause damage to external mechanisms or even personal injury, and safety cannot be guaranteed.

[0006] Therefore, it is necessary to design a pipette pump that can limit the leaked liquid to a predetermined location and issue a leakage alarm in time when leakage occurs, preventing the liquid from damaging other components of the pipette pump and effectively preventing the liquid from flowing out of the pipette pump, thereby ensuring the safety and long life of the pipette pump. Summary of the Invention

[0007] An embodiment of the present invention provides a high-safety pipette pump to solve the problem that traditional pipette pumps do not handle leakage and do not monitor leakage in a timely manner, resulting in leakage damaging the pipette pump or leaking out of the pipette pump to damage external mechanisms, and even causing personal injury.

[0008] In order to solve the above technical problems, the embodiment of the present invention provides a high-safety pipette pump, including a drive motor, a drive bracket, a screw rod, a nut, a pipette cavity and a plunger.

[0009] The screw rod and the nut are arranged on the driving bracket, and 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 to the nut, and the nut can reciprocate in the up and down directions relative to the driving bracket, and the rotation of the screw rod can drive the nut to reciprocate in the up and down directions;

[0010] The pipetting cavity is fixedly connected to the driving bracket, the pipetting cavity is located above the nut, a pipetting cavity extending in the up-down direction is provided in the pipetting cavity, one end of the plunger is fixedly connected to the 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 nut reciprocates in the up-down direction to drive the plunger to reciprocate in the pipetting cavity;

[0011] A sealing ring is provided between the driving bracket and the pipetting cavity. The sealing ring is provided around the plunger. The plunger can reciprocate relative to the sealing ring in the up-down direction. The sealing ring is used to seal the opening of the pipetting cavity close to the driving bracket.

[0012] The upper end of the nut is provided with a liquid collection groove which is open upwards. The liquid collection groove is located below the sealing ring. The downward projection of the contact point between the sealing ring and the plunger is located in the upper opening of the liquid collection groove.

[0013] A liquid level sensor is provided on the driving bracket, and the liquid level sensor includes a probe for detecting the liquid height in the liquid storage tank. When the nut moves to the uppermost position, the liquid level sensor is in a detection state, and in the detection state, the probe at least partially extends into the liquid storage tank.

[0014] Optionally, the liquid collection tank includes a liquid receiving tank and a detection tank, the liquid receiving tank is connected to the detection tank, the downward projection of the contact point between the sealing ring and the plunger is located in the upper opening of the liquid receiving tank, and the probe at least partially extends into the detection tank in the detection state.

[0015] Optionally, the diameter of the upper opening of the liquid receiving groove is 0.5-2 mm larger than the diameter of the contact point between the sealing ring and the plunger.

[0016] Optionally, the depth of the liquid receiving groove is 4-5 mm.

[0017] Optionally, in the detection state, the lower end surface of the probe is 1-2 mm higher than the bottom surface of the detection groove.

[0018] Optionally, the bottom surface of the liquid receiving groove is flush with the bottom surface of the detection groove.

[0019] Optionally, an inner surface of the pipetting cavity is provided with an internal thread structure, and the surface roughness of the inner surface of the pipetting cavity is Ra≥6.4.

[0020] Optionally, the surface roughness of the outer side surface of the plunger is Ra≤0.1.

[0021] Optionally, a guide pin is included, the nut is provided with a guide groove extending in the up and down directions, a pin hole is provided on the driving bracket, the guide pin is installed in the pin hole, the guide pin passes through the pin hole and extends into the guide groove, and the end of the guide pin extended into the guide groove can reciprocate in the guide groove in the up and down directions relative to the nut.

[0022] Optionally, the driving bracket is provided with a photoelectric sensor, and the photoelectric sensor is used to detect the position information of the nut.

[0023] The beneficial effects of the present invention are: the high-safety pipette pump provided by the present invention is provided with an upward-opening liquid accumulation groove at the upper end of the nut, the liquid accumulation groove is located below the sealing ring, and the downward projection of the contact point between the sealing ring and the plunger is located in the upper opening of the liquid accumulation groove, so as to ensure that when leakage occurs at the contact point between the sealing ring and the plunger, the leaked liquid drips into the liquid accumulation groove, and the liquid accumulation groove stores the leaked liquid, preventing the leaked liquid from flowing freely in the pipette pump or even flowing out of the pipette pump, effectively avoiding leakage from damaging the pipette pump, the external mechanism of the pipette pump and even causing personal injury, thereby ensuring the high safety of the pipette pump during use; at the same time, a liquid level sensor is arranged on the driving bracket to detect the height of the leakage in the liquid accumulation groove, monitor the leakage of the pipette pump and alarm, and remind to deal with the leakage in time or replace the pipette pump, thereby further improving the safety of the pipette pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1 is a schematic cross-sectional view of a pipetting pump in a first state according to an embodiment of the present invention;

[0026] Figure 2 yes Figure 1 A partial enlarged view of part A;

[0027] Figure 3 is a schematic cross-sectional view of a pipetting pump in a second state according to an embodiment of the present invention;

[0028] Figure 4 It is a schematic diagram of the coordination relationship between the liquid level sensor and the detection slot in one embodiment of the present invention.

[0029] The reference numerals in the specification are as follows:

[0030] 10. Drive motor; 20. Drive bracket; 21. Photoelectric sensor; 30. Screw rod; 40. Nut; 41. Guide groove; 50. Pipetting chamber; 501. Pipetting chamber; 502. Liquid inlet; 503. Liquid outlet; 60. Plunger; 70. Sealing ring; 71. O-ring; 80. Guide pin; 90. Liquid accumulating tank; 901. Liquid collecting tank; 902. Detection tank; 100. Liquid level sensor; 101. Probe. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] In the description of the present invention, it should be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0033] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0034] One embodiment of the present invention provides a high-safety pipette pump, comprising a drive motor 10, a drive bracket 20, a screw rod 30, a screw nut 40, a pipette cavity 50 and a plunger 60. Figure 1 As shown, the driving motor 10, the driving bracket 20 and the pipetting chamber 50 are arranged in sequence from bottom to top.

[0035] The screw rod 30 and the nut 40 are provided on the driving bracket 20, and the nut 40 can reciprocate relative to the driving bracket 20 in the vertical direction. Figure 1 As shown, the drive bracket 20 has a housing cavity, and the nut 40 and the screw rod 30 are disposed within the drive bracket 20, that is, within the housing cavity of the drive bracket 20; the nut 40 can reciprocate in the vertical direction relative to the drive bracket 20. The screw rod 30 is threadedly connected to the nut 40, and the drive motor 10 is used to drive the screw rod 30 to rotate about the axial direction of the screw rod 30. The rotation of the screw rod 30 drives the nut 40 to reciprocate in the vertical direction.

[0036] The drive motor 10 serves as the driving mechanism of the pipette pump. During operation, the control system sends a control signal to the driver of the drive motor 10. The driver of the drive motor 10 processes and amplifies the control signal, and then transmits the amplified control signal to the drive motor 10, and the drive motor 10 starts to work. The output shaft of the drive motor 10 is connected to the screw rod 30. When the drive motor 10 starts to work, it drives the screw rod 30 mounted on the output shaft of the drive motor 10 to rotate along its axial direction. The screw rod 30 is threadedly connected to the nut 40. The axial rotation of the screw rod 30 drives the nut 40 to move in the up and down direction, converting the axial rotational motion of the output shaft of the drive motor 10 and the screw rod 30 into linear motion of the nut 40 in the up and down direction to realize the subsequent driving process.

[0037] To ensure the stability of the overall structure, in some embodiments, the pipetting chamber 50 is fixedly connected to the drive bracket 20, and the movable chamber 50 is located above the drive bracket 20, that is, the lower end of the movable chamber 50 is fixedly connected to the upper end of the drive bracket 20; the fixed connection here can be in a detachable manner, such as a snap, or a disposable fixing manner, such as bonding or welding. The pipetting chamber 50 is located above the nut 40, and a pipetting chamber 501 extending in the up-down direction is provided in the pipetting chamber 50. 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 chamber 501, and at least a portion of the plunger 60 is accommodated in the pipetting chamber 501. In this way, the reciprocating motion of the nut 40 in the up-down direction can drive the plunger 60 to reciprocate in the pipetting chamber 501.

[0038] like Figure 1 、 Figure 2 and Figure 3 As shown, the lower end of the plunger 60 is fixed to the nut 40, and the upper end of the plunger 60 extends into the pipetting chamber 501. The movement of the nut 40 in the up and down directions can drive the plunger 60 to move in the up and down directions; the up and down movement of the plunger 60 will increase the internal pressure or form a negative pressure in the pipetting chamber 501, thereby realizing the discharge and suction actions.

[0039] 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.

[0040] like Figure 1 As shown, in some embodiments, the upper end of the nut 40 is provided with a mounting hole for the plunger 60, the lower end of the plunger 60 is connected to the mounting hole, and the upper end of the plunger 60 extends into the pipetting cavity 501. More specifically, the mounting hole of the plunger 60 is a cylindrical mounting hole that can be mated with the end of the plunger 60, and the pipetting cavity 501, the plunger 60, and the mounting hole of the plunger 60 can be coaxially arranged.

[0041] In order to ensure the sealing of the pipetting chamber 501 and prevent liquid leakage, a sealing ring 70 is provided between the driving bracket 20 and the pipetting chamber 50. The sealing ring 70 is provided around the plunger 60. The plunger 60 can reciprocate relative to the sealing ring 70 in the up and down directions. The sealing ring 70 is used to seal the opening of the pipetting chamber 501 close to the driving bracket 20. Figure 1 As shown, the sealing ring seals the lower opening of the pipetting chamber 501.

[0042] Understandably, Figure 1 and Figure 3 As shown, in one embodiment of the present invention, the upper side of the sealing ring 70 seals the lower opening of the pipetting chamber 501 , and the lower side of the sealing ring 70 seals the through hole of the upper end of the driving bracket 20 for passing the plunger 60 .

[0043] like Figure 1 and Figure 2 As shown, a sealing ring 70 mounting platform is provided between the upper end of the driving bracket 20 and the contact surface of the pipetting cavity 50, and the platform is designed around the pipetting cavity 501. The sealing ring 70 is installed at the mounting platform, as shown in FIG. Figure 1 and Figure 3 As shown, the lower end of the plunger 60 is fixedly connected to the nut 40, which drives the plunger 60 up and down. The plunger passes through the mounting hole of the plunger 60, the through hole of the drive bracket 20, the center hole of the sealing ring 70, and the lower opening of the pipetting chamber 501 from bottom to top, and extends into the interior of the pipetting chamber 501. The sealing ring 70 is installed tightly against the outer side of the plunger 60 and seals the lower opening of the pipetting chamber 501 to achieve a seal of the pipetting chamber 501. At the same time, the plunger 60 can slide up and down relative to the sealing ring 70.

[0044] In the high-safety pipette pump provided by the present invention, the plunger 60 moves up and down in close contact with the sealing ring 70. Once crystals grow on the plunger 60, 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, causing it to lose its sealing effect on the pipetting chamber 501, resulting in leakage.

[0045] like Figures 1 to 4As shown, in one embodiment of the present invention, in order to prevent the leaked liquid from flowing freely in the pipette pump, an upwardly opening liquid collection groove 90 is provided at the upper end of the nut 40. The liquid collection groove 90 is located below the sealing ring 70, and the downward projection of the contact point between the sealing ring 70 and the plunger 60 is located in the upper opening of the liquid collection groove 90. When the contact point between the sealing ring 70 and the plunger 60 causes leakage due to the sealing ring 70 being scratched, the liquid flows downward from the contact point between the sealing ring 70 and the plunger 60 under the influence of its own gravity; the liquid collection groove 90 located below the sealing ring 70 serves as a temporary storage space for the leaked liquid, and the leaked liquid flowing downward drips into the liquid collection groove 90, which can prevent the leaked liquid from flowing freely in the pipette pump or even flowing out of the pipette pump, thereby preventing the leakage from damaging the pipette pump, external mechanisms or causing personal injury, thereby ensuring the high safety of the pipette pump during use.

[0046] Combined with attachment Figure 1 and attached Figure 2 The downward projection of the contact point between the sealing ring 70 and the plunger 60 is located within the upper opening of the liquid collection groove 90, that is, the downward projection of the contact point between the sealing ring 70 and the plunger 60 in the vertical direction falls within the range of the upper opening of the liquid collection groove 90; in this way, it can be ensured that all leaked liquid flows into the liquid collection groove 90. In one embodiment, to facilitate processing and improve matching performance (such as stability), the liquid collection groove 90 is a circular groove with a circular upper opening, and the contact point between the sealing ring 70 and the plunger 60 is circular (the sealing ring 70 is an annular sealing ring 70 and the plunger 60 is a cylindrical plunger 60); it is easy to understand that in this structure, the centers of the liquid collection groove 90, the sealing ring 70 and the plunger 60 are coaxial; in this case, the diameter of the upper opening of the liquid collection groove 90 is larger than the diameter of the contact point between the sealing ring 70 and the plunger 60, which can achieve that the downward projection of the contact point between the sealing ring 70 and the plunger 60 is located within the upper opening of the liquid collection groove 90. Of course, in some other embodiments, the shape of the liquid collection groove 90 is not necessarily circular, but may be polygonal or irregular, and the plunger 60 and the sealing ring 70 may also be other shapes; no matter what shape combination is, as long as the downward projection of the contact point between the sealing ring 70 and the plunger 60 is located inside the upper opening of the liquid collection groove 90, it can be ensured that the leaked liquid flows into the liquid collection groove 90, thereby improving safety.

[0047] At the same time, if Figure 2 and Figure 3 As shown, the driving bracket 20 is provided with a liquid level sensor 100, which includes a probe 101 for detecting the liquid height in the liquid storage tank 90. ​​When the nut 40 moves to the top, the pipette pump is in the position shown in FIG. Figure 1 In the first state shown, the liquid level sensor 100 is in a detection state, and in the detection state, the probe 101 at least partially extends into the liquid storage tank 90.

[0048] The liquid accumulation tank 90 serves as a temporary storage space for leaked liquid, which can effectively prevent the leaked liquid from flowing out to a certain extent and affect the safety of the pipette pump. Because the liquid accumulation tank 90 is located inside the pipette pump, if a detection device is not set up, the operator cannot obtain the leakage situation in time and make appropriate corrections, which will cause the liquid in the liquid accumulation tank 90 to still leak out when it is full, and safety cannot be effectively guaranteed.

[0049] Therefore, in one embodiment of the present invention, the liquid level sensor 100 provided on the driving bracket 20 and the isomorphic probe 101 detect the liquid level height inside the liquid storage tank 90 when in the detection state, and can monitor the liquid height in the liquid storage tank 90 and trigger an alarm in time; through the detection of the liquid level sensor 100, liquid leakage is discovered in time, and the alarm is used to remind the staff to deal with the leakage incident in time, replace key components or replace the pipette pump, thereby improving the safety of the pipette pump during use.

[0050] like Figure 1 and Figure 2 As shown, the liquid storage tank 90 and the liquid level sensor 100 are arranged in coordination. On the one hand, when a small amount of liquid leaks, the leaked liquid is stored in the liquid storage tank 90, reducing the adverse effects of the leakage on other components or operators, and ensuring safety in use. On the other hand, the liquid level sensor 100 monitors the liquid level height of the leaked liquid in the liquid storage tank 90, and promptly alarms when it reaches a critical value, notifying the staff to deal with the leakage incident, thereby further improving the safety of the use of the pipette pump.

[0051] In one embodiment of the present invention, Figure 1 As shown, the liquid level sensor 100 is arranged on the driving bracket 20. The position of the liquid level sensor 100 is fixed and will not shake relative to the driving bracket 20, so that the detection position of the probe 101 of the liquid level sensor 100 is fixed. When the pipette pump is in the first state, that is, when the nut 40 moves to the top, the liquid level sensor 100 is in the detection state, and the probe 101 extends into the liquid accumulation tank 90 to detect the liquid height in the liquid accumulation tank 90, so as to ensure the detection stability and reliability.

[0052] In one embodiment of the present invention, in order to achieve the coordination between the probe 101 of the liquid level sensor 100 and the liquid collection tank 90, the probe 101 can be extended into the liquid collection tank 90 in the detection state. The liquid collection tank 90 can be made into a relatively large area as a whole. On the one hand, it ensures that the leaked liquid flows into the liquid collection tank 90, and on the other hand, it leaves sufficient detection space for the probe 101. However, a larger liquid collection tank 90 also means a larger leakage accommodating volume. In the case of a small amount of leakage, it cannot be effectively and timely detected. Under the demand for high-precision monitoring in the medical industry, the design of a larger liquid collection tank 90 will lead to low detection sensitivity, reduced precision, and untimely detection, which will bring greater risks to safety.

[0053] In order to improve the detection sensitivity, precision and timeliness of detection, in one embodiment of the present invention, the liquid collection tank 90 is divided into two parts: a liquid receiving tank 901 and a detection tank 902, and the liquid receiving tank 901 and the detection tank 902 are connected. The downward projection of the contact point between the sealing ring 70 and the plunger 60 is located in the upper opening of the liquid receiving tank 901, and the probe 101 at least partially extends into the detection tank 902 in the detection state.

[0054] like Figure 2 and Figure 4 As shown, the interconnected liquid receiving groove 901 and the detection groove 902 constitute the liquid collection groove 90. The liquid receiving groove 901 is designed to match the contact point between the sealing ring 70 and the plunger 60. The liquid receiving groove 901 is located below the sealing ring 70, and the downward projection of the contact point between the sealing ring 70 and the plunger 60 is located within the upper opening of the liquid receiving groove 901. It is understood that the liquid receiving groove 901 can be a circular, polygonal, or even irregular shape, as long as the downward projection of the contact point between the sealing ring 70 and the plunger 60 can be located within the upper opening of the liquid receiving groove 901. For example, in this embodiment, the liquid receiving tank 901 is a circular tank body, the sealing ring 70 is a circular sealing ring 70, the plunger 60 is a columnar body, and the vertical centers of the circular tank body, the sealing ring 70, and the plunger 60 are coaxial; at this time, the contact point between the sealing ring 70 and the plunger 60 is circular, and its diameter is smaller than the diameter of the circular opening on the upper side of the liquid receiving tank 901 to ensure that the leaked liquid can flow into the interior of the liquid receiving tank 901.

[0055] The shape of the detection groove 902 is not limited and can be rectangular, circular or elliptical, etc., as long as it is connected to the liquid receiving groove 901 and can be inserted into the probe 101 in the detection state.

[0056] The matching arrangement of the liquid receiving tank 901 and the detection tank 902, on the one hand, the liquid receiving tank 901 can match the diameter of the contact point between the sealing ring 70 and the plunger 60. On the premise that the downward projection of the contact point between the sealing ring 70 and the plunger 60 is located in the upper opening of the liquid receiving tank 901, the upper opening area of ​​the liquid receiving tank 901 is made as small as possible to ensure that the overall volume of the liquid receiving tank 901 is as small as possible; on the other hand, the detection tank 902 only needs to be designed to match the probe 101, and the volume / capacity can also be made as small as possible. By designing the liquid accumulating tank 90 composed of the liquid receiving tank 901 and the detection tank 902, the volume / capacity of the liquid accumulating tank 90 can be made as small as possible, effectively avoiding the problems of untimely detection and low detection accuracy caused by the excessive volume of the liquid accumulating tank 90, thereby improving the sensitivity and timeliness of leakage detection and further improving the safety of the pipette pump.

[0057] like Figure 2 and Figure 3As shown, in a more specific embodiment of the present invention, the liquid receiving tank 901 is divided into a liquid guide portion located on the upper side and a liquid storage portion located on the lower side. The inner diameter of the liquid guide portion gradually decreases from top to bottom, and the bottom diameter of the liquid guide portion is the same as the diameter of the liquid storage portion. It can be understood that, as Figure 2 and Figure 3 As shown, the liquid guide portion is shaped like a trumpet with an upward opening that gradually increases in size (the side surfaces tilt toward the center of the liquid guide portion from top to bottom, and the diameter of the liquid guide portion decreases). The side surfaces of the liquid storage portion are vertical, and the top of the liquid storage portion is connected to the bottom of the liquid guide portion. In the present invention, the trumpet-shaped design of the liquid guide portion can better increase the area of ​​the upper opening of the liquid receiving groove 901, so that it is sized to meet the contact points of the sealing ring 70 and the plunger 60. At the same time, the volume of the lower liquid storage portion is reduced. Through the connection between the liquid storage portion and the detection groove 902, the overall volume of the liquid accumulation groove 90 is reduced, further improving the accuracy, sensitivity, and timeliness of detection, and ensuring the safety of the pipette pump.

[0058] When crystals grow on the outer surface of the plunger 60, the size of the crystal growth will affect the depth of the scratch on the sealing ring 70, resulting in different leakage areas at the contact point between the sealing ring 70 and the plunger 60, causing the outermost layer of the leakage position to exceed the upper opening range of the liquid receiving groove 901; in order to avoid the above situation as much as possible and allow the leaked liquid to flow smoothly into the liquid receiving groove 901, in one embodiment of the present invention, the diameter of the upper opening of the liquid receiving groove 901 is 0.5-2 mm larger than the diameter of the contact point between the sealing ring 70 and the plunger 60, preferably 1 mm.

[0059] In one embodiment of the present invention, Figure 2 As shown, the plunger 60 is cylindrical, the through hole in the drive bracket 20 through which the plunger 60 passes is a cylindrical through hole, the contact portion between the sealing ring 70 and the plunger 60 is circular, and the liquid receiving groove 901 is a circular groove. The diameter of the contact portion between the sealing ring 70 and the plunger 60 is smaller than the diameter of the through hole in the drive bracket 20 through which the plunger 60 passes, and the diameter of the through hole in the drive bracket 20 through which the plunger 60 passes is smaller than the diameter of the upper opening of the liquid receiving groove 901. This ensures that leaked liquid can flow into the liquid receiving groove 901.

[0060] In one embodiment of the present invention, the depth of the liquid receiving tank 901 is set to 4-5 mm, preferably 4 mm, taking into account the impact of the volume and size of the liquid receiving tank 901 on detection accuracy and inspection timeliness. If the depth of the liquid receiving tank 901 is too large, the probe 101 will not detect the leak and issue an alarm until a long time has passed. If the depth of the liquid receiving tank 901 is too small, the design of the probe 101 will be inconvenient.

[0061] In a pipette pump provided by one embodiment of the present invention, the probe 101 performs leakage detection in a detection state (i.e., the first state of the pipette pump), and during the use of the pipette pump, the nut 40 reciprocates between the uppermost position in the first state and the lowermost position in the second state. However, any mechanical connection is subject to error, which needs to be safely avoided through design. In this usage scenario, if the lower end of the probe 101 is too close to the bottom of the detection groove 902 (i.e., the lower end surface of the probe 101 is too close to the bottom surface of the detection groove 902) in the detection state, the probe 101 may collide with the nut 40 during use of the pipette pump, damaging the sensor; if the lower end of the probe 101 is too far from the bottom of the detection groove 902 (i.e., the lower end surface of the probe 101 is too far from the bottom surface of the detection groove 902) in the detection state, the leakage may not be detected until a large amount of liquid is detected, resulting in reduced detection accuracy and untimely detection, poor alarm timeliness, and may cause the alarm to be triggered after the liquid overflows, increasing the risk. Taking the above into consideration, in one embodiment of the present invention, in the detection state, the lower end surface of the probe 101 is 1-2 mm higher than the bottom surface of the detection groove 902, preferably 1.5 mm, to ensure detection accuracy and timeliness, while ensuring the safety of the pipette pump.

[0062] like Figure 2 As shown, in order to ensure the timeliness and accuracy of detection, the bottom surface of the liquid receiving tank 901 and the bottom surface of the detection tank 902 are generally designed to be flush. In this way, the liquid level height detected in the detection tank 902 can be kept consistent with the liquid level height in the liquid receiving tank 901, so as to better control the relationship between detection and whether the leakage overflows, and ensure the coordination between the leakage situation and the detection results when the pipette pump is used.

[0063] In one embodiment of the present invention, in order to solve the problem that crystals easily form on the plunger and scratch the sealing ring during use of traditional pipetting pumps, leakage is fundamentally avoided; that is, in order to solve the problem that crystals grow on the plunger 60 and scratch the sealing ring 70, causing leakage. In one embodiment of the present invention, the surface roughness of the inner side of the pipetting chamber 501 is designed to be Ra≥6.4. By forming a rough surface on the inner side of the pipetting chamber 501, and its roughness Ra≥6.4, during the use of the pipetting pump, crystals precipitated from the solution will preferentially adhere to the rough inner surface of the pipetting chamber 501, reducing the probability of crystals precipitated from the solution adhering to the plunger 60. In this way, the surface of the plunger 60 can be ensured to be smooth, and the precipitation of crystals on the surface of the plunger 60 can be reduced; during use, the plunger 60 is not easily scratched by the growing crystals and the sealing ring 70, thereby increasing the safety of the pipetting pump and improving the safety and service life of the pipetting pump.

[0064] The working process of the high-safety pipetting pump provided by the present invention is briefly described as follows:

[0065] Figure 1The figure shows the first state of the pipette pump, which can also be called the reset state. In the first state, the nut 40 is at the top, the volume of the plunger 60 contained in the pipette cavity 501 is the largest, and the free volume of the pipette cavity 501 is the smallest. At this time, the probe is inserted into the detection groove to detect leakage. 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 cavity 501 is the smallest, and the idle volume of the pipette cavity 501 is the largest; at this time, the probe leaves the inside of the detection slot.

[0066] During the aspiration process, the pipette pump gradually transitions from its first state (i.e., reset state) to its second state. The nut 40 moves from the top to the bottom, and the plunger 60 moves downward. The volume of the plunger 60 contained within the pipette chamber 501 gradually decreases, while the unoccupied volume of the pipette chamber 501 increases. During this process, the movement of the plunger 60 creates a negative pressure within the pipette chamber 501, enabling aspiration. When the pipette pump fully transitions to the second state, aspiration ends and pipetting begins. The pipette pump can be maintained in the second state during the pipetting process.

[0067] 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 contained within the pipette chamber 501 gradually increases, while the unused volume of the pipette chamber 501 decreases. During this process, the internal pressure of the pipette chamber 501 increases due to the movement of the plunger 60, and the liquid within the chamber is discharged under the influence of this internal pressure, thus achieving drainage. When the pipette pump fully transitions to the first state, the drainage process is complete. Simultaneously, when drainage is complete, a probe is inserted into the detection slot to detect any leakage during the pipetting process.

[0068] In some embodiments, before the pipette pump starts to aspirate liquid, it is necessary to adjust the pipette pump to a first state, ie, a reset state.

[0069] To facilitate automated production, Figure 1 As shown, in one embodiment of the present invention, an internal thread structure is provided inside the pipetting chamber 501. That is, the inner wall of the pipetting chamber 501 is processed into an internal thread structure to increase the surface roughness of the inner side of the pipetting chamber 501, so that the surface roughness of the inner side of the pipetting chamber 501 is Ra≥6.4.

[0070] As a preferred feature of the present invention, in addition to the internal thread structure, other embodiments of the present invention may include multiple annular grooves arranged side by side in the vertical direction on the inner side of the pipetting chamber 501. It is understood that the purpose of both the annular grooves and the internal thread structure is to form 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 during production and more efficient; unlike the internal thread structure, the annular groove is discontinuous, requiring a processing part with a retractable outer diameter during the production process.

[0071] In some other embodiments of the present invention, a plurality of recesses may be provided inside the pipetting cavity 501 .

[0072] In order to further reduce the probability of crystals growing on the outside of the plunger 60 during solution crystallization and increase the probability of crystals growing on the inner wall of the pipetting chamber 501, in one embodiment of the present invention, the roughness Ra of the outer surface of the plunger 60 is set to be no greater than 0.1; in this way, by combining the smoother plunger 60 with the rougher inner wall of the pipetting chamber 501, the solution crystals are preferentially grown on the rougher inner wall of the pipetting chamber 501, ensuring a smaller probability of solution crystals growing on the surface of the plunger 60, further reducing the possibility of scratching the sealing ring 70, and improving safety and security.

[0073] In one embodiment of the present invention, the plunger 60 can be made of ceramic or corrosion-resistant 316 stainless steel, preferably corrosion-resistant 316 stainless steel. More specifically, the plunger 60 is made of the corrosion-resistant 316 stainless steel and is sprayed with PTFE (polytetrafluoroethylene). PTFE (polytetrafluoroethylene) has excellent acid and alkali resistance and is virtually insoluble in any solvent. Furthermore, PTFE (polytetrafluoroethylene) has an extremely low coefficient of friction, ensuring that the surface roughness of the outer side of the plunger 60 is less than 0.1, thereby further reducing the friction generated during plunger movement. Because fluorine-containing materials have low surface energy, which exhibits strong hydrophobicity (similar to a lotus leaf), the solution has very low viscosity on its surface, significantly reducing adhesion, thereby reducing crystal precipitation on the surface of the plunger 60 and improving the reliability and service life of the pipette pump.

[0074] like Figure 1 As shown, in order to ensure that the nut 40 can move more stably in the up and down direction, in one embodiment of the present invention, a guide groove 41 extending in the up and down direction is provided on the nut 40, and a pin hole is provided on the drive bracket 20. A guide pin 80 is installed in the pin hole. One end of the guide pin 80 passes through the pin hole and extends into the guide groove 41. The design of the guide groove 41 and the guide pin 80 can effectively fix the axial angle of the nut 40, preventing the nut 40 from rotating in the axial direction under the drive of the screw rod 30, making the movement of the nut 40 more stable.

[0075] In this embodiment, the guide pin 80 is inserted into the guide groove 41 to prevent the nut 40 from rotating axially; at the same time, the guide pin 80 can reciprocate in the up and down directions in the guide groove 41, serving as a movement track for the nut 40, guiding the up and down movement of the nut 40 while limiting the axial angle.

[0076] In order to further enhance the sealing strength of the lower opening of the pipetting cavity 501, in one embodiment of the present invention, an O-ring 71 is provided on the side of the sealing ring 70 close to the pipetting cavity 50, and the O-ring 71 further enhances the sealing performance. Figure 2 As shown, the O-ring 71 is coaxially arranged with the sealing ring 70 and is arranged above the sealing ring 70, that is, 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.

[0077] like Figure 2 As shown, in one embodiment of the present invention, to accommodate the application scenarios of the pipette pump, a liquid inlet 502 and a liquid outlet 503 are provided on the pipette chamber 50. The liquid inlet 502 is connected to the pipette chamber 501, and the liquid outlet 503 is connected to the pipette chamber 501. More specifically, both the liquid inlet 502 and the liquid outlet 503 are provided with on / off valves. When aspirating liquid, the liquid inlet 502 is open and the liquid outlet 503 is closed; when discharging liquid, the liquid inlet 502 is closed and the liquid outlet 503 is open.

[0078] In other application scenarios, only one opening may be provided as needed, that is, liquid inlet and liquid outlet are achieved through one opening.

[0079] In one embodiment of the present invention, a photoelectric sensor 21 is provided on the driving bracket 20, and the photoelectric sensor 21 is used to detect the position information of the nut 40. Figure 1 As shown, in one embodiment of the present invention, a photoelectric sensor 21 is disposed on the upper side of the drive bracket 20 to detect the position information of the nut 40. More specifically, the photoelectric sensor 21 corresponds to detecting the position information of the nut 40 when the pipette pump is in the first state (i.e., the nut 40 is at the uppermost end), and is used to determine whether the nut 40 has been reset before and after pipetting, and whether the pipette pump has returned to the reset state (i.e., the first state). Generally, the photoelectric sensor 21 uses a light source to detect position information, and the nut 40 is provided with a baffle that can block the light source. When the pipette 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, recognizing that the pipette pump has been successfully reset.

[0080] In some embodiments, considering the control accuracy requirements, a stepper motor can be selected as the drive motor 10 to meet the high-precision control requirements; of course, in some scenarios with general control accuracy requirements, other drive motors 10 can also be used.

[0081] exist Figure 1 and Figure 2 In the embodiment of the present invention shown, a stepper motor is selected as the drive motor 10. The control system of the pipette pump sends a pulse signal to the stepper motor driver. The stepper motor driver processes and amplifies the pulse signal and transmits the amplified signal to the stepper motor. After receiving the control signal, the stepper motor begins operation.

[0082] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A high-safety pipetting pump, characterized in that: Including drive motor, drive bracket, screw rod, nut, pipetting chamber and plunger, The screw rod and the nut are arranged on the driving bracket, and 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 to the nut, and the nut can reciprocate in the up and down directions relative to the driving bracket, and the rotation of the screw rod can drive the nut to reciprocate in the up and down directions; The pipetting cavity is fixedly connected to the driving bracket, the pipetting cavity is located above the nut, a pipetting cavity extending in the up-down direction is provided in the pipetting cavity, one end of the plunger is fixedly connected to the 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 nut reciprocates in the up-down direction to drive the plunger to reciprocate in the pipetting cavity; A sealing ring is provided between the driving bracket and the pipetting cavity. The sealing ring is provided around the plunger. The plunger can reciprocate relative to the sealing ring in the up-down direction. The sealing ring is used to seal the opening of the pipetting cavity close to the driving bracket. The upper end of the nut is provided with a liquid collection groove which is open upwards. The liquid collection groove is located below the sealing ring. The downward projection of the contact point between the sealing ring and the plunger is located in the upper opening of the liquid collection groove. A liquid level sensor is provided on the driving bracket, and the liquid level sensor includes a probe for detecting the liquid height in the liquid storage tank. When the nut moves to the uppermost position, the liquid level sensor is in a detection state, and in the detection state, the probe at least partially extends into the liquid storage tank.

2. The high-safety pipetting pump according to claim 1, characterized in that: The liquid collection tank includes a liquid receiving tank and a detection tank. The liquid receiving tank is connected to the detection tank. The downward projection of the contact point between the sealing ring and the plunger is located in the upper opening of the liquid receiving tank. In the detection state, the probe at least partially extends into the detection tank.

3. The high-safety pipetting pump according to claim 2, characterized in that: The diameter of the upper opening of the liquid receiving groove is 0.5-2 mm larger than the diameter of the contact point between the sealing ring and the plunger.

4. The high-safety pipetting pump according to claim 2, characterized in that: The depth of the liquid receiving groove is 4-5 mm.

5. The high-safety pipetting pump according to claim 2, characterized in that: In the detection state, the lower end surface of the probe is 1-2 mm higher than the bottom surface of the detection groove.

6. The high-safety pipetting pump according to claim 2, characterized in that: The bottom surface of the liquid receiving groove is flush with the bottom surface of the detection groove.

7. The high-safety pipetting pump according to claim 1, characterized in that: An internal thread structure is provided on the inner side of the pipetting cavity, and the surface roughness of the inner side of the pipetting cavity is Ra≥6.

4.

8. The high-safety pipetting pump according to claim 7, characterized in that: The surface roughness of the outer side of the plunger is Ra≤0.

1.

9. The high-safety pipetting pump according to claim 1, characterized in that: It includes a guide pin, the nut is provided with a guide groove extending in the up and down directions, the driving bracket is provided with a pin hole, the guide pin is installed in the pin hole, the guide pin passes through the pin hole and extends into the guide groove, and the end of the guide pin extended into the guide groove can reciprocate in the guide groove along the up and down directions relative to the nut.

10. The high-safety pipetting pump according to claim 1, characterized in that: The driving bracket is provided with a photoelectric sensor, and the photoelectric sensor is used to detect the position information of the nut.

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