CN110658350A - Electric liquid transfer device - Google Patents

Abstract

The present invention provides an electric pipette, comprising: the loading mechanism comprises a support frame with a fixed fulcrum, a first screw rod, a driven belt wheel, a driving belt wheel and a first motor, wherein the driving belt wheel is connected with the driven belt wheel through a synchronous belt; the actuating mechanism is positioned on the front side of the fixed pivot and comprises a frame, an injection tube, a plunger vertically inserted into the injection tube, a dislocation slider connected with the plunger, a second screw rod in threaded connection with the dislocation slider and a second motor, wherein the first screw rod drives the injection tube to move axially through rotating the driving frame, the injection tube moves downwards through the axial direction and is spliced with a pipetting head, the second screw rod drives the plunger to move axially through rotating the driving dislocation slider, and the plunger sucks or discharges liquid from the pipetting head through the axial movement. The invention adopts the conventional motor, can realize the shortest distance between the reciprocating motion axis of the liquid-transferring actuating mechanism and the perpendicular line of the mechanism pivot, and reduces the harmful overturning moment and fatigue deformation generated when the liquid-transferring actuating mechanism is frequently connected with the liquid-transferring head in a press-in manner along the axis.

Description

Electric liquid transfer device

Technical Field

The invention relates to sample adding equipment, in particular to an electric pipettor.

Background

In the detection work in the fields of medicine, food, biology and the like, a lot of pretreatment work needs to be carried out on biological materials and samples (generally in liquid state), the operations such as pipetting, sample adding, mixing and the like can be completed in batches in a short time by adopting high-throughput automatic biological sample pretreatment equipment, and an electric pipettor is a core technical unit in an automatic biological sample treatment system. According to different suction driving methods of the electric pipettor for liquid, the electric pipettor is divided into two types: gas-liquid mixing displacement type and gas displacement type.

The gas-liquid mixing displacement type pipettor adopts a liquid plunger, and the liquid plunger and sample liquid are isolated by an air gap reserved in a pipetting head, and the gas-liquid mixing displacement type pipettor has the advantages that an electric reciprocating motion injection mechanism, a pressure sensor and the like are separated, only one thin guide pipe enters a pipetting execution mechanism, so that the design pressure and load of a pipetting execution mechanism assembly are greatly reduced, and the requirement of the minimum center distance of a vessel is met; meanwhile, the distance between the reciprocating axis of the pipetting actuating mechanism and the perpendicular line of the mechanism pivot can be minimized, and the harmful overturning moment and the fatigue deformation of a supporting component generated when the pipetting actuating mechanism is connected with the pipetting head in a pressing-in manner frequently along the axis of the pipetting actuating mechanism; and because the separation air gap between the liquid plunger and the sample liquid is very small, the pipetting precision is high. The defects of the existing gas-liquid pipeline pressure system, more components, complex debugging and high maintenance cost; when the room temperature is low, liquid leakage is likely to occur.

The gas displacement type pipettor adopts a solid plunger, the reciprocating motion of the solid plunger is realized by a motor through a coupling or other connecting parts to drive a screw rod or a synchronous toothed belt, namely, components such as an electric reciprocating motion injection mechanism, a pressure sensor and the like are assembled with a liquid transfer actuating mechanism, complex pressure pipelines and pump systems are not needed, the structure level is clear, and the workload of unit structure installation and debugging is greatly reduced. The first existing gas displacement pipettor adopts a small-diameter high-rotation-speed motor with a speed reducer to form a blade type pipetting actuating mechanism unit, and although the shortest distance between the reciprocating motion axis of the pipetting actuating mechanism and the mechanism fulcrum perpendicular line can be realized, the pipetting actuating mechanism unit is extremely expensive, high in transportation, maintenance and maintenance cost and high in debugging difficulty; the second existing gas displacement type pipettor adopts a conventional motor, is low in price, low in transportation and maintenance cost and convenient to debug, but has the following defects: the distance between the reciprocating axis of the pipetting actuating mechanism and the perpendicular line of the mechanism fulcrum is increased, and when the pipetting actuating mechanism is downwards connected with the pipetting head frequently in a press-in mode along the axis of the pipetting actuating mechanism, the generated harmful overturning moment is increased, and the support component is easy to generate fatigue deformation.

Disclosure of Invention

The invention aims to provide an electric pipettor which can solve the problem of high price existing in the prior art of adopting a small-diameter high-rotation-speed motor, and can also solve the problems of large distance between a reciprocating motion axis of a pipetting execution mechanism and a vertical line of a mechanism fulcrum, large harmful overturning moment and fatigue deformation generated when the pipetting execution mechanism is downwards connected with a pipetting head in a press-in mode along the axis in the prior art of adopting a conventional motor.

In order to achieve the above object, the present invention provides an electric pipette, comprising: the loading mechanism comprises a support frame with a fixed pivot, a first screw rod which is vertically arranged on the support frame in a rotatable manner and is positioned on the front side of the fixed pivot, a driven pulley connected above the first screw rod, a driving pulley connected with the driven pulley through a horizontally arranged synchronous belt, and a first motor coaxially connected with the driving pulley, wherein the first motor is positioned on the rear side of the fixed pivot and can drive the first screw rod to rotate sequentially through the driving pulley, the synchronous belt and the driven pulley; the actuating mechanism is positioned on the front side of the fixed pivot and comprises a rack which is arranged on the supporting frame and can slide up and down, an injection tube which is vertically fixed on the rack and can be inserted with a pipetting head, a plunger which is vertically inserted in the injection tube, a dislocation slide block which is arranged above the injection tube and is connected with the plunger, a second screw rod which is vertically arranged on the rack and is in threaded connection with the dislocation slide block in a rotatable manner, and a second motor which is positioned above the second screw rod and is connected with the second screw rod, wherein the second motor can drive the second screw rod to rotate, the first screw rod drives the rack to drive the injection tube to axially move by rotating, the injection tube is inserted with the pipetting head by axially moving downwards, and the second screw rod drives the dislocation slide block to drive the plunger to axially move by rotating, the plunger sucks or discharges liquid into or out of the pipetting head by axial reciprocating movement.

The electric pipette as described above, wherein the lower end of the syringe has a plug wall that can be inserted into the pipette head, a through hole is provided on the sidewall of the syringe near the plug wall, the through hole is located above the plug wall and below the plunger, the actuator further includes a pressure detection device, the pressure detection device includes a sampling tube and a pressure sensor provided on the rack, one end of the sampling tube is inserted into the through hole and communicated with the syringe, and the other end of the sampling tube is connected with the pressure sensor.

The electric pipette as described above, wherein the actuator further comprises a tubular buffer inserted into the tip of the syringe, the buffer being located below the plunger.

The electric pipette as described above, wherein the actuating mechanism further includes a pipette head withdrawing device, the pipette head withdrawing device includes a pressing block that is axially slidably sleeved outside the injection tube, an ejector rod that is fixed above the pressing block and is axially movably and vertically installed on the frame, an elastic member sleeved outside the ejector rod, and an adjusting ring fixedly sleeved outside the ejector rod, the adjusting ring is located above the elastic member, the adjusting ring and the elastic member are separated by the frame, an upper end of the elastic member abuts against the frame, a lower end of the elastic member abuts against the pressing block, the ejector rod is located below the dislocation slider, the dislocation slider pushes the ejector rod and the pressing block to apply pressure to a top end of the pipette head sleeved outside the injection tube by moving downward, so that the pipette head drops from the injection tube, the adjusting ring can be propped against the rack when the ejector rod moves downwards for a preset distance.

The electric pipette as described above, wherein the top of the pressing block is further provided with a first blocking piece, the bottom of the dislocation slider is further provided with a second blocking piece, the lower portion of the rack is provided with a signal conditioning plate, the signal conditioning plate is located below the dislocation slider and above the pressing block, the signal conditioning plate is provided with a plunger position sensor for detecting the position of the plunger and a pipette head position sensor for detecting the position of the pipette head, the pipette head position sensor detects the position of the pipette head by detecting the position of the first blocking piece, and the plunger position sensor detects the position of the plunger by detecting the position of the second blocking piece.

The electric pipette as described above, wherein the actuator further includes an optical axis fixed on the frame and parallel to the second screw, a linear bearing disposed in the offset slide block, and an anti-backlash nut disposed in the offset slide block, the optical axis passing through the linear bearing, and the second screw passing through the anti-backlash nut and threadedly connected to the offset slide block.

The electronic pipettor as above, wherein, have in the dislocation slider with the connecting hole of the coaxial setting of plunger, the lower extreme of connecting hole has the diameter taper hole that gradually expands from bottom to top, the top of plunger is connected with the connecting rod, the top of connecting rod is connected with the bulb, the bulb is located in the connecting hole and sit in on the taper hole, the diameter of connecting rod is less than the minimum diameter of taper hole, the connecting hole internal fixation has the rubber buffer, the rubber buffer is located bulb top and top are supported the bulb.

The electric pipette as described above, wherein the rack includes a top frame, a bottom frame located below the top frame, and a side plate connected between the top frame and the bottom frame, the top frame, the side plate, and the bottom frame enclose a sliding space, the second motor is fixed at the top of the top frame, the second screw passes through the sliding space, the upper end of the second screw is connected to the second motor, the lower end of the second screw is connected to the bottom frame through a bearing, the dislocation slider is located in the sliding space, and the injection tube passes through the bottom frame and is fixedly connected to the bottom frame.

The electric pipette is characterized in that the support frame is a long-strip-shaped hollow groove block, the first screw is arranged in the groove block, the front side of the groove block is open, the rear side plate of the groove block is a vertically-arranged connecting plate, the fixed pivot is located on the connecting plate, a vertical guide rail is arranged in the groove block, a guide rail slider and a nut slider are fixed on one side of the groove block towards the frame, the guide rail slider extends into the groove block and is in sliding fit with the guide rail, the nut slider extends into the groove block and is in threaded connection with the first screw, and the first screw drives the nut slider to drive the frame and the guide rail slider to slide up and down along the guide rail.

The electric pipette as described above, wherein the support frame further includes a top plate and a bottom plate, the top plate is fixed to the top of the connection plate, the bottom plate is fixed to the bottom of the connection plate, the driving pulley is installed at the top of the top plate, the top plate extends toward the rear side of the connection plate to form an extension plate, the driven pulley is installed at the top of the extension plate, the first motor is inversely fixed to the bottom of the extension plate, the upper end of the first screw is connected to the top plate through a bearing, and the lower end of the first screw is connected to the bottom plate through a bearing.

The electric pipettor has the characteristics and advantages that:

1. the electric liquid transfer device of the invention adopts the conventional motor, compared with the motor with small diameter and high rotating speed adopted in the prior art, the price is lower, because the size of the conventional motor is larger, when in arrangement, the first motor is arranged at the rear side of the fixed pivot, the torque of the first motor is transmitted to the first screw rod by adopting a driving belt wheel, a synchronous belt and a driven belt wheel which are positioned above the first screw rod, the actuating mechanism is arranged at the front side of the fixed pivot, the second motor is arranged above the second screw rod to directly drive the second screw rod to rotate, therefore, the first motor and the second motor do not occupy too much space between the reciprocating axis of the actuating mechanism and the fixed pivot, the shortest distance between the reciprocating axis of the actuating mechanism and the fixed pivot can be realized, and harmful overturning moment and fatigue deformation generated when the actuating mechanism is connected with the pipetting head in a pressing-in mode frequently along the axis downwards are reduced;

2. according to the electric pipettor, the sampling point of the pressure sensor is arranged at the narrow air gap at the joint of the injection cavity and the pipetting head in the injection tube, and due to the small sampling air gap, under the cooperation of the high-sensitivity pressure sensor, when impurities or clots in liquid block the pipetting head, the detection is easy, and the sensitivity of pressure detection is effectively improved;

3. according to the electric pipettor, the press block of the pipetting head withdrawing device is directly sleeved outside the injection tube, the liquid transferring head can be withdrawn by driving the ejector rod and the press block to move downwards through the staggered slide block, the driving device of the plunger is used as the driving device of the press block, the structure is simple and compact, a pipetting head withdrawing mechanism with a complex structure and a driving electromagnetic component are not needed, and the cost is reduced;

4. according to the electric pipettor, the injection tube can be directly inserted into the pipetting head, so that the injection pump and the injection cavity are combined into a whole, the structure is simple and compact, the injection tube and the plunger piston are lengthened, and the measuring range is enlarged;

5. the electric pipettor has the advantages of simple and compact structure, low price, low transportation and maintenance cost and convenient debugging.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:

fig. 1 is a front view of one embodiment of an electric pipette of the present invention;

FIG. 2 is a cross-sectional view of an actuator according to the present invention;

fig. 3 is a schematic perspective view of one embodiment of an electric pipette of the present invention.

Main element number description:

100. a loading mechanism;

101. a support frame; 1011. a connecting plate; 1012. a top plate; 1013. a base plate; 1014. an extension plate;

102. a first screw; 103. a driven pulley; 104. a synchronous belt;

105. a driving pulley; 106. a first motor; 107. a guide rail; 108. a reference position sensor;

109. fixing a fulcrum;

200. an actuator;

201. a frame; 2011. a top frame; 2012. a chassis; 2013. a side plate; 2014. mounting grooves;

2015. a through hole; 2016. a wire slot; 2017. a sliding space;

202. an injection tube; 2021. a plug-in wall; 2022. perforating; 2023. an annular projection;

2024. an O-shaped sealing ring;

203. a plunger; 204. a staggered slide block; 205. a second screw;

206. a second motor; 207. a buffer; 208. a sampling tube; 209. briquetting; 210. a top rod;

211. an elastic member; 212. an adjusting ring; 213. a first jackscrew; 214. a second jackscrew; 215. a first baffle plate;

216. a signal conditioning board; 217. a second baffle plate; 218. an optical axis; 219. a connecting rod; 220. a ball head;

221. a rubber plug; 222. adjusting the nut; 223. an O-shaped sealing ring; 224. a hollow flange;

225. a guide rail slider; 226. a nut slider; 227. a gap eliminating nut;

300. and (4) a liquid transferring head.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings. In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

Unless otherwise specified, the "front side" referred to herein is the left side of the present invention as shown in fig. 1, the "back side" is the right side of the present invention as shown in fig. 1, and the directions "up", "down", "vertical", "horizontal", etc. referred to herein are the upper, lower, vertical, horizontal, etc. directions as shown in fig. 1 of the present invention, and are all referred to herein.

As shown in fig. 1, 2 and 3, the present invention provides an electric pipette, which can be mounted on a work frame, and includes a loading mechanism 100 for loading a pipetting head 300 and an executing mechanism 200 for sucking and discharging liquid, wherein the pipetting head 300 is a standardized pipetting head with a volume of 50 to 1000 microliters, and the pipetting head 300 is a disposable item, generally made of plastic, belonging to a consumable item, and is discarded after completing one liquid treatment; wherein the content of the first and second substances,

the loading mechanism 100 comprises a support frame 101 with a fixed fulcrum 109 (or called mechanism fulcrum), or a fixed fulcrum for supporting the electric pipette is formed at the joint of the support frame 101 and the working frame;

the loading mechanism 100 further comprises a first screw 102 vertically installed on the support frame 101 in a rotatable manner and located in front of the fixed pivot 109, a driven pulley 103 connected above the first screw 102, a driving pulley 105 connected with the driven pulley 103 through a horizontally arranged synchronous belt 104, and a first motor 106 coaxially connected with the driving pulley 105, wherein the first motor 106, the driving pulley 105 and the driven pulley 103 are all installed on the support frame 101, the first motor 106 is located behind the fixed pivot 109, the first motor 106 can drive the first screw 102 to rotate through the driving pulley 105, the synchronous belt 104 and the driven pulley 103 in sequence, and the first motor 106 is provided with an encoder;

the execution mechanism 200 is located at the front side of the fixed fulcrum 109, the execution mechanism 200 comprises a rack 201 which can be installed on the support frame 101 in a vertical sliding manner, an injection tube 202 which is vertically fixed on the rack 201 and can be inserted into the pipetting head 300, a plunger 203 which is vertically inserted into the injection tube 202, a dislocation slider 204 which is arranged above the injection tube 202 and is connected with the plunger 203, a second screw 205 which is vertically installed on the rack 201 in a rotating manner and is in threaded connection with the dislocation slider 204, and a second motor 206 which is located above the second screw 205 and is connected with the top end of the second screw 205, an injection cavity is formed in the injection tube 202, the second screw 205 can be driven to rotate by the second motor 206, the second motor 206 is provided with an encoder, the first screw 102 drives the injection tube 202 to move upwards or downwards in the axial direction by rotating the rack 201, the injection tube 202 is inserted into the pipetting head 300 by moving downwards in the axial direction, thereby realizing the loading of the, the second screw 205 drives the dislocation slide 204 to drive the plunger 203 to move axially upwards or axially downwards by rotating, the plunger 203 sucks liquid into the pipetting head 300 by moving axially upwards, and the plunger 203 discharges the liquid in the pipetting head 300 by moving axially downwards, so that the liquid is sucked and discharged.

During the use, install electronic pipettor on the work rest to make electronic pipettor unsettled, can put various containers or check out test set below electronic pipettor, accomplish through pipetting head 300 and move liquid, operation such as application of sample.

The first motor 106 and the second motor 206 adopted by the electric pipette of the present invention are ordinary motors (conventional motors) and are low in price, and because the size of the ordinary motors is large, when the electric pipette is arranged, the first motor 106 is arranged at the rear side of the fixed fulcrum 109 (namely, the mechanism fulcrum), the driving pulley 105, the synchronous belt 104 and the driven pulley 103 which are positioned above the first screw 102 are adopted to transmit the torque of the first motor 106 to the first screw 102, the actuating mechanism 200 is arranged at the front side of the fixed fulcrum 109, the second motor 206 is arranged above the second screw 205 to directly drive the second screw 205 to rotate, so that the first motor 106 and the second motor 206 do not occupy too much space between the reciprocating axis of the actuating mechanism 200 (namely, the central axes of the second motor 206 and the second screw 205) and the fixed fulcrum 109, the perpendicular distance between the reciprocating axis of the actuating mechanism 200 and the fixed fulcrum 109 can be minimized, the harmful overturning moment and fatigue deformation generated when the actuator 200 is frequently connected with the pipetting head 300 in a press-in manner along the axis are reduced;

in addition, the first motor 106 with larger volume is arranged behind the fixed fulcrum 109, so that the left-right width of the part of the electric pipette, which is positioned at the front side of the fixed fulcrum 109, can be reduced;

in addition, because the injection tube 202 can be directly inserted with the pipetting head 300, the injection pump and the injection cavity are combined into a whole, the structure is simple and compact, and the injection tube 202 and the plunger 203 are lengthened, so that the range is enlarged.

In one embodiment, as shown in fig. 2, the actuator 200 further comprises a tubular buffer 207, the buffer 207 is inserted into the end of the injection tube 202, i.e. into the end of the injection cavity, the buffer 207 is located below the plunger 203, the gas in the buffer 207 acts as a gas plunger, and the inner diameter of the buffer 207 is smaller than the inner diameter of the injection cavity to meet the high accuracy requirement in a small range.

As shown in fig. 2, in one embodiment, the lower end of the syringe 202 has an insertion wall 2021 capable of being inserted into the pipetting head 300, the insertion wall 2021 is hermetically connected to the pipetting head 300, a through hole 2022 is formed on a side wall of the syringe 202 adjacent to the insertion wall 2021, the through hole 2022 is located above the insertion wall 2021 and below the plunger 203, the buffer 207 is inserted into the insertion wall 2021, the buffer 207 is located below the through hole 2022, the electric pipette further includes a pressure detection device, the pressure detection device includes a sampling tube 208 and a pressure sensor disposed on the rack 201, one end of the sampling tube 208 is inserted into the through hole 2022 and communicated with the syringe 202, the other end of the sampling tube 208 is connected to the pressure sensor, the sampling tube 208 is a metal elongated tube, for example, the pressure sensor is a micro-pressure sensor, and has high sensitivity.

In the embodiment, the sampling point of the pressure sensor is arranged at the narrow air gap at the joint of the injection cavity and the pipetting head 300 in the injection tube 202, and because the sampling air gap is very small, under the cooperation of the high-sensitivity pressure sensor, when impurities or clots in liquid block the pipetting head 300, the detection is very easy, and the sensitivity of pressure detection is effectively improved; the pressure detection with high signal-to-noise ratio can also realize bubble false image identification and liquid level detection, and fully meets the main pressure data detection in liquid processing.

As shown in fig. 2, specifically, the outer wall surface of the insertion wall 2021 has two annular protrusions 2023 arranged up and down, the cross-sectional shape of the annular protrusion 2023 is arc-shaped, when the insertion wall 2021 is inserted into the pipetting head 300, the annular protrusion 2023 is attached to the inner wall surface of the pipetting head 300, and an O-ring 2024 is provided between the two annular protrusions 2023 to form a static seal between the syringe 202 and the pipetting head 300. When the pipetting head 300 is loaded, the first motor 106 drives the first screw rod 102 to rotate, and the first screw rod 102 drives the actuator 200 to move downwards through rotation until the two annular protrusions 2023 of the insertion wall 2021 of the syringe 202 are pressed into the pipetting head 300, so that the operation of loading the pipetting head 300 is completed.

As shown in fig. 1, 2 and 3, in one embodiment, the actuator 200 further comprises a pipetting head withdrawing device, the pipetting head withdrawing device comprises a pressing block 209 which is sleeved outside the syringe 202 and can slide axially, a push rod 210 which is fixed above the pressing block 209 and can move axially and vertically and is vertically installed on the frame 201, an elastic member 211 which is sleeved outside the push rod 210, and an adjusting ring 212 which is fixed outside the push rod 210, for example, the elastic member 211 is a spring, the adjusting ring 212 is positioned above the elastic member 211, the adjusting ring 212 and the elastic member 211 are separated by the frame 201, the upper end of the elastic member 211 abuts against the frame 201, the lower end of the elastic member 211 abuts against the pressing block 209, the push rod 210 is positioned below the misplacing slider 204, the misplacing slider 204 pushes the push rod 210 and the pressing block 209 by moving downwards to apply pressure to the top end of the pipetting head 300 which is sleeved outside the syringe 202, so that the pipetting head 300 falls off the syringe 202, the adjusting ring 212 can abut against the frame 201 when the, to limit the ejector pin 210 and the press piece 209.

In this embodiment, the pressing block 209 of the pipetting head withdrawing device is directly sleeved outside the injection tube 202, the plunger 210 and the pressing block 209 are driven by the dislocation slide block 204 to move downwards so as to withdraw the pipetting head 300, and the driving device (i.e., the dislocation slide block 204, the second screw 205 and the second motor 206) of the plunger 203 is directly used as the driving device of the pressing block 209, so that the structure is simple and compact, a pipetting head withdrawing mechanism and a driving electromagnetic component with complicated structures are not needed, and the cost is reduced.

As shown in fig. 2, specifically, the side wall of the adjusting ring 212 is provided with a first jackscrew 213 along the radial direction, the first jackscrew 213 is in threaded connection with the adjusting ring 212 and abuts against the side wall of the ejector rod 210 to fix the adjusting ring 212 and the ejector rod 210 together, when the position of the adjusting ring 212 on the ejector rod 210 needs to be adjusted, the first jackscrew 213 is unscrewed, the adjusting ring 212 is moved up and down, the adjusting ring 212 is moved to a proper position, and then the first jackscrew 213 is screwed to fix the adjusting ring 212 and the ejector rod 210 together, so that the adjustment is very convenient;

the side wall of the pressing block 209 is provided with a second jackscrew 214 along the radial direction, the second jackscrew 214 is in threaded connection with the pressing block 209 and props against the side wall of the ejector rod 210 so as to fix the pressing block 209 and the ejector rod 210 together, when the relative position of the ejector rod 210 and the pressing block 209 needs to be adjusted, the second jackscrew 214 is unscrewed, the ejector rod 210 moves up and down, the ejector rod 210 is moved to a proper position and then is screwed, the ejector rod 210 and the pressing block 209 are fixed together, and the adjustment is very convenient.

As shown in fig. 2, further, a first blocking piece 215 is further disposed on the top of the pressing block 209, when the pressing block 209 pushes the pipetting head 300 downward, the first blocking piece 215 can move downward along with the pressing block 209, a signal conditioning plate 216 is disposed on the lower portion of the rack 201, the signal conditioning plate 216 is located above the pressing block 209, a pipetting head position sensor for detecting the position of the pipetting head 300 is disposed on the signal conditioning plate 216, the pipetting head position sensor detects the position of the pipetting head 300 by detecting the position of the first blocking piece 215, and the signal conditioning plate 216 can transmit a position signal of the pipetting head 300 to the computer. For example, the pipetting head position sensor is a photoelectric sensor.

As shown in fig. 2, further, a second stopper 217 is further disposed at the bottom of the dislocation slider 204, when the dislocation slider 204 drives the plunger 203 to move up and down, the second stopper 217 can move up and down along with the dislocation slider 204, the signal conditioning plate 216 is located below the dislocation slider 204, a plunger position sensor for detecting the position of the plunger 203 is disposed on the signal conditioning plate 216, the plunger position sensor detects the position of the plunger 203 by detecting the position of the second stopper 217, and the signal conditioning plate 216 can transmit a position signal of the plunger 203 to the computer. For example, the plunger position sensor is an opto-electronic sensor.

As shown in fig. 1, 2 and 3, in one embodiment, the actuator 200 further includes an optical axis 218 fixed on the frame 201 and parallel to the second screw 205, two linear bearings disposed in the misalignment slider 204, and an anti-backlash nut 227 disposed in the misalignment slider 204, where the optical axis 218 is a slide rail of the misalignment slider 204 for guiding the misalignment slider 204 to slide, for example, the optical axis 218 is two, the two optical axes 218 are disposed side by side at an interval, the two linear bearings are two, each optical axis 218 passes through each linear bearing, and the second screw 205 passes through the anti-backlash nut 227 and is screwed with the misalignment slider 204 through the anti-backlash nut 227. When the second motor 206 drives the second screw 205 to rotate, the anti-backlash nut 227 drives the misalignment sliding block 204 to slide up and down along the optical axis 218.

As shown in fig. 2, in an embodiment, the plunger 203 is flexibly connected to the misplacement slider 204, specifically, the misplacement slider 204 has a connecting hole coaxially disposed with the plunger 203 therein, a lower end of the connecting hole has a tapered hole with a diameter gradually expanding from bottom to top, a top end of the plunger 203 is connected to a connecting rod 219, a top end of the connecting rod 219 is connected to a ball 220, the ball 220 is located in the connecting hole and sits on the tapered hole, the diameter of the connecting rod 219 is smaller than a minimum diameter of the tapered hole, so that the connecting rod 219 can pass through the tapered hole, a rubber plug 221 is fixed in the connecting hole, and the rubber plug 221 is located above the ball 220 and abuts against the ball 220. With such a connection structure, even if the plunger 203 and the misalignment slider 204 are relatively fixed in the axial direction, the plunger 203 is allowed to move in the axial direction while being appropriately shifted in the left and right direction, and the plunger 203 is less likely to be damaged than in a rigid connection.

As shown in fig. 2, the plunger 203 is further connected with the top end of the syringe 202 in a sliding and sealing manner, specifically, a cap-shaped adjusting nut 222 is sleeved on the outer side of the top end of the syringe 202, the plunger 203 can axially and slidably pass through the adjusting nut 222, an O-ring 223 is clamped between the top end of the syringe 202 and the top wall of the adjusting nut 222, the O-ring 223 is located between the side wall of the adjusting nut 222 and the plunger 203, and the syringe 202 and the plunger 203 can be connected with each other in a sliding and sealing manner by the O-ring 223 and the adjusting nut 222, so that dynamic sealing is realized.

As shown in fig. 1 and 3, in a specific embodiment, the frame 201 includes a top frame 2011, a bottom frame 2012 located below the top frame 2011, and a side plate 2013 connected between the top frame 2011 and the bottom frame 2012, where the top frame 2011 and the bottom frame 2012 are both block-shaped, the top frame 2011, the side plate 2013, and the bottom frame 2012 enclose a sliding space 2017, the second motor 206 is fixed on the hollow flange 224 at the top of the top frame 2011, the second screw 205 passes through the sliding space 2017, the upper end of the second screw 205 passes through the top frame 2011 and is connected with the second motor 206, the lower end of the second screw 205 is connected with the bottom frame 2012 through a bearing, for example, the second screw 205 and a rotor of the second motor 206 are an integrated structure; the optical axis 218 penetrates through the sliding space 2017, the upper end of the optical axis 218 is fixedly connected with the top frame 2011, the lower end of the optical axis 218 is fixedly connected with the bottom frame 2012, the dislocation slider 204 is positioned in the sliding space 2017, the injection tube 202 penetrates through the bottom frame 2012 and is fixedly connected with the bottom frame 2012, and the upper end of the injection tube 202 extends into the sliding space 2017; the push rod 210 penetrates through the bottom frame 2012, the adjusting ring 212 is positioned above the bottom frame 2012 and in the sliding space 2017, the adjusting ring 212 can abut against the top surface of the bottom frame 2012 when the push rod 210 moves downwards for a preset distance, the elastic member 211 is positioned below the bottom frame 2012, and the upper end of the elastic member 211 abuts against the bottom surface of the bottom frame 2012;

the bottom of chassis 2012 is equipped with mounting groove 2014, signal conditioning board 216 is located in the mounting groove 2014 of chassis 2012 bottom, still be equipped with perforating hole 2015 that link up from top to bottom on chassis 2012, perforating hole 2015 is adjacent and is linked together with mounting groove 2014, first separation blade 215 and second separation blade 217 aim at from top to bottom with this perforating hole 2015, first separation blade 215 can stretch into in this perforating hole 2015 upwards, detect with the liquid-transfering head position sensor on the signal conditioning board 216, second separation blade 217 can stretch into in this perforating hole 2015 downwards, detect with plunger 203 position sensor on the signal conditioning board 216.

Specifically, for example, the injection tube 202, the ejector rod 210, the optical axes 218 and the second screw 205 are sequentially arranged in a direction close to the support frame 101, the two optical axes 218 are arranged side by side left and right, the first blocking piece 215 and the second blocking piece 217 are positioned at the rear side of the ejector rod 210 and at the front side of the second screw 205, the signal conditioning board 216 is positioned at the rear side of the first blocking piece 215 and the second blocking piece 217, the side plate 2013 of the rack 201 is positioned at the rear side of the bottom frame 2012, the signal conditioning board 216 is positioned below the side plate 2013, a wire slot 2016 is arranged in the side plate 2013 and is communicated with the mounting groove 2014 where the signal conditioning board 216 is positioned, a signal wire passes through the wire slot 2016, one end of the signal wire is connected with the signal conditioning board 216, the other end of the signal wire is connected with the second motor 206, the signal conditioning board 216 transmits a position signal of the plunger 203 to the second motor 206, the second motor 206 controls, to control the initial position of the misplacement slider 204 and thus the position of the plunger 203.

As shown in fig. 1 and 3, in one embodiment, the supporting frame 101 is an elongated hollow slot block, the front side of the slot block is open, the rear side plate 2013 of the slot block is a vertically arranged connecting plate 1011, the fixed pivot 109 is located on the connecting plate 1011, specifically, the working frame is located on the rear side of the connecting plate 1011, the fixed pivot 109 is formed at the connection between the rear side of the connecting plate 1011 and the working frame, a vertical guide rail 107 is arranged in the slot block, for example, the guide rail 107 is fixed on the front side surface of the connecting plate 1011, the first screw 102 is arranged in the slot block, the side of the frame 201 facing the slot block is fixed with a guide rail slide block 225 and a nut slide block 226, the guide rail slide block 225 extends into the slot block, and with guide rail 107 sliding fit, nut slider 226 stretches into the channel block to with first screw 102 threaded connection, nut slider 226 drives frame 201 and guide rail slider 225 and slides up and down along guide rail 107 when first screw 102 rotates. The combined structure of the support frame 101 and the frame 201 in the embodiment is simple and compact.

For example, there are two rail sliders 225, two rail sliders 225 are disposed at an interval from top to bottom, the upper rail slider 225 is fixed to the rear side of the top frame 2011 of the frame 201, the lower rail slider 225 is fixed to the rear side of the connection plate 1011 of the frame 201, the nut slider 226 is located between the two rail sliders 225, and the nut slider 226 is fixed to the lower rail slider 225. Preferably, the nut sliding block 226 is an anti-backlash nut, and the frame 201 and the guide rail sliding block 225 are of an integrated structure and have high structural strength.

As shown in fig. 2, in one embodiment, the slot block further includes a top plate 1012 and a bottom plate 1013, the top plate 1012 is fixed on the top of the connecting plate 1011, the bottom plate 1013 is fixed on the bottom of the connecting plate 1011, the driving pulley 105 is installed on the top of the top plate 1012, the top plate 1012 extends towards the rear side of the connecting plate 1011 to form an extending plate 1014, the driven pulley 103 is installed on the top of the extending plate 1014, the first motor 106 is fixed upside down on the bottom of the extending plate 1014, the upper end of the first screw 102 is connected with the top plate 1012 through a bearing, and the lower end of the first screw 102 is connected with the bottom plate 1013. Specifically, the top plate 1012 and the bottom plate 1013 are flanges to facilitate connection.

As shown in fig. 2, the upper part of the slot block is further provided with a reference position sensor 108 for detecting the position of the rack 201 in the vertical direction, the reference position sensor 108 is located below the top plate 1012 of the slot block and adjacent to the top plate 1012 of the slot block, and the reference position sensor 108 is located above the two rail sliders 225, so that the reference position sensor 108 can detect the position of the rack 201 when the rack 201 slides up and down along the rail 107.

When the electric pipette of the present invention is used for pipetting, in order to avoid cross contamination of liquid, the liquid cannot enter the injection cavity in the injection tube 202, cannot enter the buffer 207, and can only enter the pipetting head 300, so the range of liquid treatment depends on the volume of the pipetting head 300, and the range of the electric pipette depends on the volume of the plunger 203.

Before imbibing, the position of the plunger 203 needs to be initialized, specifically, the dislocation slider 204 drives the plunger 203 to move downwards, once the signal conditioning plate 216 detects the position of the second stop piece 217 on the dislocation slider 204, a zero position signal is output to the second motor 206, the second motor 206 controls the dislocation slider 204 to stop moving through the second screw 205, and the position is recorded as an initial position (reset) of the dislocation slider 204 and the plunger 203, and when imbibing, the plunger 203 starts to move upwards from the initial position;

when the pipetting head 300 needs to be withdrawn after completing one pipetting operation, the misplacing slide block 204 is allowed to overrun downwards for a few millimeters, at this time, the misplacing slide block 204 drives the mandril 210 downwards, the mandril 210 and the pressing block 209 which is fixedly connected together move downwards, the pipetting head 300 is withdrawn, and the initial position is detected again (reset) before next pipetting.

The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent changes and modifications that can be made by one skilled in the art without departing from the spirit and principles of the invention should be considered within the scope of the invention. It should be noted that the components of the present invention are not limited to the above-mentioned whole application, and various technical features described in the present specification can be selected to be used alone or in combination according to actual needs, so that the present invention naturally covers other combinations and specific applications related to the invention.

Claims (10)

1. An electric pipette, comprising:

the loading mechanism comprises a support frame with a fixed pivot, a first screw rod which is vertically arranged on the support frame in a rotatable manner and is positioned on the front side of the fixed pivot, a driven pulley connected above the first screw rod, a driving pulley connected with the driven pulley through a horizontally arranged synchronous belt, and a first motor coaxially connected with the driving pulley, wherein the first motor is positioned on the rear side of the fixed pivot and can drive the first screw rod to rotate sequentially through the driving pulley, the synchronous belt and the driven pulley;

the actuating mechanism is positioned on the front side of the fixed pivot and comprises a rack which is arranged on the supporting frame and can slide up and down, an injection tube which is vertically fixed on the rack and can be inserted with a pipetting head, a plunger which is vertically inserted in the injection tube, a dislocation slide block which is arranged above the injection tube and is connected with the plunger, a second screw rod which is vertically arranged on the rack and is in threaded connection with the dislocation slide block in a rotatable manner, and a second motor which is positioned above the second screw rod and is connected with the second screw rod, wherein the second motor can drive the second screw rod to rotate, the first screw rod drives the rack to drive the injection tube to axially move by rotating, the injection tube is inserted with the pipetting head by axially moving downwards, and the second screw rod drives the dislocation slide block to drive the plunger to axially move by rotating, the plunger sucks or discharges liquid into or out of the pipetting head by axial reciprocating movement.

2. The electric pipette according to claim 1, wherein the lower end of the syringe has a plug wall that can be inserted into the pipetting head, a through hole is provided in a side wall of the syringe adjacent to the plug wall, the through hole is located above the plug wall and below the plunger, the actuator further comprises a pressure detection device, the pressure detection device comprises a sampling tube and a pressure sensor provided on the rack, one end of the sampling tube is inserted into the through hole and communicates with the syringe, and the other end of the sampling tube is connected to the pressure sensor.

3. The electric pipette of claim 1, wherein the actuator further comprises a tubular bumper inserted within the tip of the syringe, the bumper being located below the plunger.

4. The electric pipette according to claim 1, wherein the actuator further comprises a pipetting head retracting device, the pipetting head retracting device comprises a pressing block which is sleeved outside the syringe in an axially sliding manner, a push rod which is fixed above the pressing block and is vertically mounted on the frame in an axially movable manner, an elastic member which is sleeved outside the push rod, and an adjusting ring which is fixedly sleeved outside the push rod, the adjusting ring is located above the elastic member, the adjusting ring and the elastic member are separated by the frame, the upper end of the elastic member abuts against the frame, the lower end of the elastic member abuts against the pressing block, the push rod is located below the dislocation slider, and the dislocation slider pushes the push rod and the pressing block to apply pressure to the top end of the pipetting head which is sleeved outside the syringe by moving the push rod and the pressing block downwards so as to enable the pipetting head to fall off the syringe, the adjusting ring can be propped against the rack when the ejector rod moves downwards for a preset distance.

5. The electric pipette according to claim 4, wherein a first blocking piece is further provided at the top of the pressing block, a second blocking piece is further provided at the bottom of the dislocation slider, a signal conditioning plate is provided at the lower part of the frame, the signal conditioning plate is located below the dislocation slider and above the pressing block, a plunger position sensor for detecting the position of the plunger and a pipetting head position sensor for detecting the position of the pipetting head are provided on the signal conditioning plate, the pipetting head position sensor detects the position of the pipetting head by detecting the position of the first blocking piece, and the plunger position sensor detects the position of the plunger by detecting the position of the second blocking piece.

6. The electric pipette of claim 1, wherein the actuator further comprises an optical axis fixed to the frame and parallel to the second screw, a linear bearing disposed within the offset slide, and an anti-backlash nut disposed within the offset slide, wherein the optical axis passes through the linear bearing, and the second screw passes through the anti-backlash nut and is threadedly coupled to the offset slide.

7. The electric pipette according to claim 1, wherein the dislocation slide block has a connecting hole coaxially disposed with the plunger, the lower end of the connecting hole has a tapered hole with a diameter gradually expanding from bottom to top, the top end of the plunger is connected with a connecting rod, the top end of the connecting rod is connected with a ball head, the ball head is located in the connecting hole and sits on the tapered hole, the diameter of the connecting rod is smaller than the minimum diameter of the tapered hole, a rubber plug is fixed in the connecting hole, and the rubber plug is located above the ball head and abuts against the ball head.

8. The electric pipette according to any one of claims 1 to 7, wherein the frame comprises a top frame, a bottom frame located below the top frame, and a side plate connected between the top frame and the bottom frame, the top frame, the side plate, and the bottom frame enclose a sliding space, the second motor is fixed at the top of the top frame, the second screw rod passes through the sliding space, the upper end of the second screw rod is connected with the second motor, the lower end of the second screw rod is connected with the bottom frame through a bearing, the offset slide block is located in the sliding space, and the injection tube passes through the bottom frame and is fixedly connected with the bottom frame.

9. The electric pipette according to any one of claims 1 to 7, wherein the support frame is an elongated hollow channel block, the first screw is disposed in the channel block, a front side of the channel block is open, a rear side plate of the channel block is a vertically disposed connecting plate, the fixed pivot is located on the connecting plate, a vertical guide rail is disposed in the channel block, a guide rail slider and a nut slider are fixed on a side of the frame facing the channel block, the guide rail slider extends into the channel block and is in sliding fit with the guide rail, the nut slider extends into the channel block and is in threaded connection with the first screw, and the first screw drives the nut slider to drive the frame and the guide rail slider to slide up and down along the guide rail by rotation.

10. The electric pipette according to claim 9, wherein the support frame further comprises a top plate fixed to the top of the connection plate and a bottom plate fixed to the bottom of the connection plate, the driving pulley is mounted on the top of the top plate, the top plate extends toward the rear side of the connection plate to form an extension plate, the driven pulley is mounted on the top of the extension plate, the first motor is fixed upside down to the bottom of the extension plate, the upper end of the first screw is connected to the top plate through a bearing, and the lower end of the first screw is connected to the bottom plate through a bearing.

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