High-safety pipetting pump

Abstract

The high-safety liquid transfer pump comprises a driving motor, a driving support, a lead screw, a nut, a liquid transfer cavity and a plunger, a liquid accumulation groove with an upward opening is formed in the upper end of the nut and located below a sealing ring, and the downward orthographic projection of the contact position of the sealing ring and the plunger is located in the opening in the upper side of the liquid accumulation groove; when liquid leakage occurs at the contact part of the sealing ring and the plunger, the liquid flows into the liquid accumulation groove and is prevented from flowing out, so that the use safety is improved; meanwhile, the liquid level sensor is arranged on the driving support and used for detecting the liquid level height of leaked liquid in the liquid accumulation groove, the liquid leakage condition can be monitored in time, an alarm is given, and a user is reminded to dispose a liquid leakage event or replace a related mechanism or even replace the liquid transfer pump, so that the use safety of the liquid transfer pump is improved.

Description

Technical Field

[0001] The 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 accurate 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, and then converts the rotational motion into linear motion through the coordinated action of the screw rod and the nut, so that the plunger moves up and down in the cavity to change the volume to achieve the purpose of absorption or discharge of liquid.

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

[0004] The existing pipette pumps can be accurate to microliters, but there are still safety issues in the industry. Since the working medium of most pipette pumps is a solution that is easy to precipitate crystals, the crystals precipitated after the equipment has been used for a period of time are easy to adhere to the ceramic plunger. As the crystals continue to precipitate and grow, the hard crystals will move up and down with the plunger and scratch the sealing ring, causing leakage. The leaked medium is often corrosive and will seriously damage the circuit inside the equipment, causing 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 out of the pipette pump; this will cause the leaked liquid to corrode the pipette pump, causing damage to the pipette pump, and the 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 position and promptly issue a leakage alarm when leakage occurs, prevent the liquid from damaging other parts of the pipette pump, and effectively prevent 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] The embodiment of the present invention provides a high-safety pipette pump to solve the problem that the traditional pipette pump does not handle the leakage and does not monitor the leakage in time, resulting in leakage damaging the pipette pump or leakage of the pipette pump damaging the external mechanism, and even causing personal injury.

[0008] In order to solve the above technical problems, an embodiment of the present invention provides a high-safety liquid transfer pump, including a driving motor, a driving bracket, a screw rod, a screw nut, a liquid transfer cavity and a 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 with the nut, and the nut can reciprocate relative to the driving bracket in the up and down direction, and the rotation of the screw rod can drive the nut to reciprocate in the up and down direction; 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 and down directions, and 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 accumulation groove which is open upwards, the liquid accumulation groove is located below the sealing ring, and the downward orthographic projection of the contact point between the sealing ring and the plunger is located in the upper opening of the liquid accumulation groove; The driving bracket is provided with a liquid level sensor, and the liquid level sensor includes a probe for detecting the height of the liquid 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.

[0009] 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.

[0010] 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.

[0011] Optionally, the depth of the liquid receiving groove is 4-5 mm.

[0012] 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.

[0013] Optionally, the bottom surface of the liquid receiving groove is flush with the bottom surface of the detection groove.

[0014] 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 has a Ra≥6.4.

[0015] Optionally, the surface roughness of the outer side surface of the plunger is Ra≤0.1.

[0016] Optionally, it includes a guide pin, the nut is provided with a guide groove extending in the up-down direction, 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 extending into the guide groove can reciprocate in the guide groove in the up-down direction relative to the nut.

[0017] Optionally, the driving bracket is provided with a photoelectric sensor, and the photoelectric sensor is used to detect the position information of the nut.

[0018] The beneficial effects of the present invention are as follows: the high-safety pipette pump provided by the present invention is provided with an upwardly open 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 or even causing personal injury, and 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

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0020] Figure 1 is a cross-sectional schematic diagram of a pipetting pump in a first state according to an embodiment of the present invention; Figure 2 yes Figure 1 A partial enlarged view of part A; Figure 3 is a schematic cross-sectional view of a liquid transfer pump in a second state according to an embodiment of the present invention; 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.

[0021] The reference numerals in the specification are as follows: 10. Drive motor; 20. Drive bracket; 21. Photoelectric sensor; 30. Screw rod; 40. Nut; 41. Guide groove; 50. Transfer chamber; 501. Transfer chamber; 502. Liquid inlet; 503. Liquid outlet; 60. Plunger; 70. Sealing ring; 71. O-ring; 80. Guide pin; 90. Liquid accumulating groove; 901. Liquid collecting groove; 902. Detection groove; 100. Liquid level sensor; 101. Probe. DETAILED DESCRIPTION

[0022] 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 in conjunction with 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 used to limit the present invention.

[0023] 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" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] An embodiment of the present invention provides a high-safety liquid transfer pump, including a drive motor 10, a drive bracket 20, a screw rod 30, a screw nut 40, a liquid transfer chamber 50 and a plunger 60. Figure 1 As shown, the driving motor 10, the driving bracket 20 and the liquid transfer chamber 50 are arranged in sequence from bottom to top.

[0026] The screw rod 30 and the screw nut 40 are disposed on the driving bracket 20, and the screw nut 40 can reciprocate relative to the driving bracket 20 in the up and down directions. Figure 1As shown, the driving bracket 20 has a housing cavity, and the nut 40 and the screw rod 30 are arranged inside the driving bracket 20, that is, arranged in the housing cavity of the driving bracket 20; the nut 40 can reciprocate relative to the driving bracket 20 in the up-down direction. The screw rod 30 is threadedly connected with the nut 40, and the driving motor 10 is used to drive the screw rod 30 to rotate around the axial direction of the screw rod 30, and the rotation of the screw rod 30 can drive the nut 40 to reciprocate in the up-down direction.

[0027] The drive motor 10 serves as the driving mechanism of the liquid transfer 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. The drive motor 10 starts to work, driving 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 a linear motion of the nut 40 in the up and down direction, so as to realize the subsequent driving process.

[0028] To ensure the stability of the overall structure, in some embodiments, the liquid transfer cavity 50 is fixedly connected to the driving bracket 20, and the movable cavity 50 is located above the driving bracket 20, that is, the lower end of the movable cavity 50 is fixedly connected to the upper end of the driving bracket 20; the fixed connection here can be in a detachable manner, such as snaps, etc., or a one-time fixing manner, such as bonding or welding, etc. The liquid transfer cavity 50 is located above the nut 40, and a liquid transfer cavity 501 extending in the up-down direction is provided in the liquid transfer cavity 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 liquid transfer cavity 501, and at least part of the plunger 60 is accommodated in the liquid transfer cavity 501, so that the reciprocating motion of the nut 40 in the up-down direction can drive the plunger 60 to reciprocate in the liquid transfer cavity 501.

[0029] 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.

[0030] In some embodiments, the plunger 60 is a cylindrical plunger 60 and the pipetting chamber 501 is a cylindrical space extending in the up-down direction.

[0031] like Figure 1As 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 in the mounting hole, and the upper end extends into the liquid transfer cavity 501. More specifically, the mounting hole of the plunger 60 is a cylindrical mounting hole that can be matched with the end of the plunger 60, and the liquid transfer cavity 501, the plunger 60 and the mounting hole of the plunger 60 can be coaxially arranged.

[0032] 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 .

[0033] Understandable, such as 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 .

[0034] 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 liquid transfer cavity 50, and the platform is designed around the liquid transfer 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, and the nut 40 drives the plunger 60 to move up and down; the plunger passes through the mounting hole of the plunger 60, the through hole on the driving bracket 20, the central hole of the sealing ring 70, the lower opening of the liquid transfer cavity 501 from bottom to top, and extends into the interior of the liquid transfer cavity 501. The sealing ring 70 is installed tightly against the outer side of the plunger 60 and seals the lower opening of the liquid transfer cavity 501 to achieve sealing of the liquid transfer cavity 501, and the plunger 60 can slide up and down relative to the sealing ring 70.

[0035] In the high-safety pipetting 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 between 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.

[0036] 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 accumulating groove 90 is provided at the upper end of the nut 40, and the liquid accumulating 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 accumulating groove 90. When the contact point between the sealing ring 70 and the plunger 60 causes leakage due to the scratching of the sealing ring 70, 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 accumulating 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 accumulating 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 leaked liquid from damaging the pipette pump, external mechanisms or causing personal injuries, and ensuring the high safety of the pipette pump during use.

[0037] Combined with Figure 1 and attached Figure 2 , the downward orthographic projection of the contact point between the sealing ring 70 and the plunger 60 is located in the upper opening of the liquid accumulating groove 90, that is, the downward orthographic projection of the contact point between the sealing ring 70 and the plunger 60 in the vertical direction falls into the inner range of the upper opening of the liquid accumulating groove 90; in this way, it can be ensured that all the leaked liquid flows into the liquid accumulating groove 90. In one embodiment, in order to facilitate processing and improve matching performance (such as stability), the liquid accumulating groove 90 is selected as a circular groove, the upper opening is circular, and the contact point between the sealing ring 70 and the plunger 60 is circular (the sealing ring 70 is selected as an annular sealing ring 70, and the plunger 60 is selected as a cylindrical plunger 60); it is easy to understand that in this structure, the centers of the liquid accumulating groove 90, the sealing ring 70 and the plunger 60 are coaxial; at this time, the diameter of the upper opening of the liquid accumulating groove 90 is larger than the diameter of the contact point between the sealing ring 70 and the plunger 60, that is, it can be achieved that the downward orthographic projection of the contact point between the sealing ring 70 and the plunger 60 is located in the upper opening of the liquid accumulating 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, 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.

[0038] At the same time, if Figure 2 and Figure 3 As shown, a liquid level sensor 100 is provided on the driving bracket 20, and the liquid level sensor 100 includes a probe 101 for detecting the liquid height in the liquid storage tank 90. ​​When the nut 40 moves to the uppermost position, that is, the pipette pump is in the position as 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.

[0039] The liquid accumulation groove 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 use of the pipette pump; because the liquid accumulation groove 90 is located inside the pipette pump, if a detection device is not provided, the operator cannot obtain the leakage situation in time and make appropriate corrections, which will cause the liquid in the liquid accumulation groove 90 to still leak out when it is full, and safety cannot be effectively guaranteed.

[0040] 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 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 staff is reminded through the alarm to deal with the leakage incident in time, replace key components or replace the pipette pump, thereby improving the safety of the use process of the pipette pump.

[0041] 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, thereby reducing the adverse effects of the leakage on other components or operators and ensuring the safety of 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.

[0042] 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, thereby ensuring the detection stability and reliability.

[0043] In one embodiment of the present invention, in order to achieve the cooperation 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, and the liquid collection tank 90 can be made into a relatively large area as a whole, which ensures that the leaked liquid flows into the liquid collection tank 90 on the one hand, and leaves enough detection space for the probe 101 on the other hand. However, a larger area of ​​the liquid collection tank 90 also means a larger volume for accommodating leaked liquid, and in the case of a small amount of leaked liquid, it cannot be effectively and timely detected; under the demand for high-precision monitoring in the medical industry, the design of a larger area of ​​the liquid collection tank 90 will lead to low detection sensitivity, reduced precision and untimely detection, which will bring greater risks to safety.

[0044] In order to improve the detection sensitivity, precision and timeliness of detection, in one embodiment of the present invention, the liquid accumulation tank 90 is divided into two parts, namely a liquid receiving tank 901 and a detection tank 902, and the liquid receiving tank 901 and the detection tank 902 are connected, 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 receiving tank 901, and the probe 101 at least partially extends into the detection tank 902 in the detection state.

[0045] like Figure 2 and Figure 4 As shown, the liquid receiving groove 901 and the detection groove 902 connected to each other form the liquid storage groove 90. The liquid receiving groove 901 is made 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 in the upper opening of the liquid receiving groove 901. It can be understood that the liquid receiving groove 901 can be a circular, polygonal or even irregular groove, so as to ensure that the downward projection of the contact point between the sealing ring 70 and the plunger 60 can be located inside the upper opening of the liquid receiving groove 901. For example, in this embodiment, the liquid receiving groove 901 is a circular groove body, the sealing ring 70 is a circular ring sealing ring 70, the plunger 60 is a columnar body, and the vertical centers of the circular groove 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 groove 901 to ensure that the leaked liquid can flow into the interior of the liquid receiving groove 901.

[0046] 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 match the insertion of the probe 101 in the detection state.

[0047] The matching arrangement of the liquid receiving groove 901 and the detection groove 902, on the one hand, the liquid receiving groove 901 can match the diameter of the contact point between the sealing ring 70 and the plunger 60, and 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 groove 901, the upper opening area of ​​the liquid receiving groove 901 is made as small as possible to ensure that the overall volume of the liquid receiving groove 901 is as small as possible; on the other hand, the detection groove 902 only needs to be designed to match the probe 101, and the volume / capacity can also be made as small as possible. Through the design of the liquid receiving groove 90 composed of the detection groove 901 and the liquid accumulating groove 90, the volume / capacity of the liquid accumulating groove 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 groove 90, so as to improve the sensitivity and timeliness of leakage detection, and further improve the safety of the use of the pipette pump.

[0048] 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 at the upper side and a liquid storage portion located at 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 Figure 2 and Figure 3 As shown, the liquid guide part is in the shape of a trumpet with an upward opening that gradually increases (the side surface is inclined toward the center of the liquid guide part from top to bottom, and the diameter of the liquid guide part becomes smaller and smaller), the side surface of the liquid storage part is vertical, and the top of the liquid storage part is combined with the bottom of the liquid guide part. In the present invention, the trumpet-shaped design of the liquid guide part can better increase the area of ​​the upper opening of the liquid receiving groove 901, so that it matches the size of the contact point with the sealing ring 70 and the plunger 60; at the same time, the volume of the lower liquid storage part is made small, and the overall volume of the liquid storage groove 90 is reduced through the connection between the liquid storage part and the detection groove 902, further improving the accuracy, sensitivity and timeliness of the detection, and ensuring the safety of the use of the pipette pump.

[0049] When crystals grow on the outer surface of the plunger 60, the size of the crystal growth will affect the depth of the scratch of the sealing ring 70, resulting in different sizes of 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 0.5-2mm larger than the diameter of the contact point between the sealing ring 70 and the plunger 60, preferably 1mm.

[0050] In one embodiment of the present invention, Figure 2 As shown, the plunger 60 is cylindrical, the through hole on the driving bracket 20 through which the plunger 60 passes is a cylindrical through hole, the contact 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 between the sealing ring 70 and the plunger 60 is smaller than the diameter of the through hole on the driving bracket 20 through which the plunger 60 passes, and the diameter of the through hole on the driving 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 the leaked liquid can flow into the liquid receiving groove 901.

[0051] 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 full consideration the influence of the volume and size of the liquid receiving tank 901 on the detection accuracy and timeliness of the inspection. If the depth of the liquid receiving tank 901 is too large, the probe 101 will detect the leakage and alarm after a long time; if the depth of the liquid receiving tank 901 is too small, it is not convenient for the design of the probe 101.

[0052] In a liquid transfer pump provided by an embodiment of the present invention, the probe 101 performs leakage detection in a detection state (i.e., the first state of the liquid transfer pump), and during the use of the liquid transfer pump, the nut 40 reciprocates between the uppermost position in the first state and the lowermost position in the second state. However, all mechanically matched connections have errors, which need to be safely avoided by design. In this use 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 the use of the liquid transfer 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 be detected only when the amount is large, 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 danger. 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 use of the pipette pump.

[0053] 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, so that 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 the detection and whether the leakage overflows, and ensure the coordination between the leakage situation and the detection result when the pipette pump is used.

[0054] In one embodiment of the present invention, in order to solve the problem that the traditional liquid transfer pump is easy to form crystals on the plunger and scratch the sealing ring to cause leakage during use, the occurrence of leakage is fundamentally avoided; that is, in order to solve the problem that crystals grow on the plunger 60, scratch the sealing ring 70, and cause leakage. In one embodiment of the present invention, the surface roughness of the inner side of the liquid transfer chamber 501 is designed to be Ra≥6.4. By forming a rough surface on the inner side of the liquid transfer chamber 501, and its roughness Ra≥6.4, during the use of the liquid transfer pump, the crystals precipitated from the solution will preferentially adhere to the inner surface of the liquid transfer chamber 501 with a rough surface, reducing the probability of the crystals precipitated from the solution adhering to the plunger 60, so that 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 easy to scratch the sealing ring 70 due to the growth of crystals, which increases the safety of the use of the liquid transfer pump and improves the safety and service life of the liquid transfer pump.

[0055] The working process of the high-safety liquid transfer pump provided by the present invention is briefly described as follows: Figure 1The first state of the pipette pump is shown in FIG. 1 , 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 slot to detect the leakage. Figure 3 As shown, it 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 groove.

[0056] During the liquid aspiration process, the liquid transfer pump gradually changes from the first state (i.e., the reset state) to the second state, the nut 40 moves from the top to the bottom, the plunger 60 moves downward, the volume of the plunger 60 contained in the liquid transfer chamber 501 gradually decreases, and the idle volume of the liquid transfer chamber 501 increases; during this process, the liquid transfer chamber 501 forms a negative pressure due to the movement of the plunger 60 to achieve liquid aspiration. When the liquid transfer pump completely changes to the second state, the liquid aspiration process ends and liquid transfer begins; during the liquid transfer process, the liquid transfer pump can be maintained in the second state.

[0057] During the liquid discharge process, the liquid transfer pump gradually changes from the second state to the first state (i.e., the reset state), the nut 40 moves from the bottom to the top, the plunger 60 moves upward, the volume of the plunger 60 contained in the liquid transfer chamber 501 gradually increases, and the idle volume of the liquid transfer chamber 501 decreases; during this process, the liquid transfer chamber 501 is affected by the movement of the plunger 60, and the internal pressure of the liquid transfer chamber 501 increases, and the liquid inside the liquid transfer chamber 501 will be discharged under the influence of the internal pressure to achieve liquid discharge. When the liquid transfer pump completely changes to the first state, the liquid discharge process ends. At the same time, when the liquid discharge is completed, the probe is inserted into the detection slot to detect whether there is leakage during the liquid transfer process.

[0058] 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.

[0059] To facilitate automated production, Figure 1 As shown, in one embodiment of the present invention, an internal thread structure is provided inside the pipetting cavity 501. That is, the inner wall of the pipetting cavity 501 is processed into an internal thread structure to increase the surface roughness of the inner side of the pipetting cavity 501, so that the surface roughness of the inner side of the pipetting cavity 501 Ra≥6.4.

[0060] As a preferred mode of the present invention, in addition to the internal thread structure, in other embodiments of the present invention, a plurality of annular grooves arranged side by side in the vertical direction may be provided on the inner side of the liquid transfer chamber 501. It can be understood that the purpose of the annular groove 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 in production and more efficient; and the annular groove is different from the internal thread structure, which is discontinuous, and a processing part with a retractable outer diameter is required in the production process.

[0061] In some other embodiments of the present invention, a plurality of pits may be provided inside the pipetting chamber 501 .

[0062] 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 a smoother plunger 60 with a 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 growing solution crystals on the surface of the plunger 60, further reducing the possibility of scratching the sealing ring 70, and improving safety and security.

[0063] In one embodiment of the present invention, the plunger 60 can be made of ceramic material or corrosion-resistant 316 stainless steel material, preferably corrosion-resistant 316 stainless steel material. More specifically, the plunger 60 is made of 316 stainless steel material with excellent corrosion resistance, and PTFE (polytetrafluoroethylene) is sprayed on its surface; PTFE (polytetrafluoroethylene) has excellent acid and alkali resistance, is almost insoluble in any solvent, and the friction coefficient of PTFE (polytetrafluoroethylene) is extremely low, ensuring that the surface roughness of the outer side of the plunger 60 is less than 0.1, which can better reduce the friction generated when the plunger moves; because the fluorine-containing material has a lower surface energy, and the low surface energy will show a stronger hydrophobicity (similar to the lotus leaf), the solution and its surface have a very low viscosity, which can greatly reduce adhesion, thereby reducing the precipitation of crystals on the surface of the plunger 60, and improving the reliability and service life of the pipette pump.

[0064] like Figure 1 As shown, in order to ensure that the nut 40 can move more stably in the up-down direction, in one embodiment of the present invention, a guide groove 41 extending in the up-down direction is provided on the nut 40, a pin hole is provided on the driving bracket 20, and a guide pin 80 is installed in the pin hole, and 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, prevent the nut 40 from rotating in the axial direction under the drive of the screw rod 30, and make the movement of the nut 40 more stable.

[0065] In this embodiment, the guide pin 80 is inserted into the guide groove 41 to prevent the nut 40 from axially rotating; at the same time, the guide pin 80 can reciprocate in the guide groove 41 along the up and down directions, serving as a movement track of the nut 40, guiding the up and down movement of the nut 40 while limiting the axial angle.

[0066] In order to further enhance the sealing strength of the lower opening of the pipetting chamber 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 chamber 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 , namely, 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 .

[0067] like Figure 2 As shown, in one embodiment of the present invention, in order to match the application scenario of the liquid transfer pump, a liquid inlet 502 and a liquid outlet 503 are provided on the liquid transfer cavity 50, the liquid inlet 502 is connected to the liquid transfer cavity 501, and the liquid outlet 503 is connected to the liquid transfer cavity 501. More specifically, the liquid inlet 502 and the liquid outlet 503 are both provided with a switch valve, when the liquid is aspirated, the liquid inlet 502 is opened, and the liquid outlet 503 is closed; when the liquid is discharged, the liquid inlet 502 is closed, and the liquid outlet 503 is opened.

[0068] In other application scenarios, as required, only one opening may be provided, that is, liquid inlet and liquid outlet are achieved through one opening.

[0069] 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 driving bracket 20 to detect the position information of the nut 40; more specifically, the photoelectric sensor 21 corresponds to the position information of the nut 40 when the pipette pump is in the first state (i.e., the nut 40 is located at the uppermost end), and is used to determine whether the nut 40 is reset in place before and after the pipetting, and whether the pipette pump returns to the reset state (i.e., the first state). Generally, the photoelectric sensor 21 uses a light source to detect the position information, and a baffle that can block the light source is disposed on the nut 40. 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 and recognizes that the pipette pump is reset successfully.

[0070] 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.

[0071] exist Figure 1 and Figure 2 In the embodiment of the present invention shown, a stepper motor is selected as the driving motor 10, and the control system of the pipette pump sends a pulse signal to the stepper motor driver, and 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 starts working.

[0072] 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 the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A high-safety liquid transfer pump, characterized in that: It includes a driving motor, a driving bracket, a screw rod, a screw nut, a pipetting chamber and a 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 with the nut, and the nut can reciprocate relative to the driving bracket in the up and down direction, and the rotation of the screw rod can drive the nut to reciprocate in the up and down direction; 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 and down directions, and 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 accumulation groove which is open upwards, the liquid accumulation groove is located below the sealing ring, and the downward orthographic projection of the contact point between the sealing ring and the plunger is located in the upper opening of the liquid accumulation groove; The driving bracket is provided with a liquid level sensor, and the liquid level sensor includes a probe for detecting the height of the liquid 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 liquid transfer 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, and the probe at least partially extends into the detection tank in the detection state.

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

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

1.

9. The high-safety liquid transfer 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-down direction, 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 extending into the guide groove can reciprocate in the guide groove in the up-down direction relative to the nut.

10. The high-safety liquid transfer 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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