CN210720436U - Electric liquid transfer device - Google Patents

Abstract

The utility model provides an electric pipette, comprising: a loading mechanism, including a support frame with a fixed fulcrum, a first screw, a driven pulley, a driving pulley connected with the driven pulley through a synchronous belt, and a first Motor; actuator, located on the front side of the fixed fulcrum, including a frame, an injection pipe, a plunger inserted in the injection pipe, a dislocation slider connected to the plunger, a second screw thread connected to the dislocation slider, and a second motor , the first screw drives the injection tube to move axially by rotating the drive frame, the injection tube is inserted into the pipetting head by moving downward, the second screw drives the plunger to move axially by rotating the dislocation slider, and the plunger moves through the axial The movement draws liquid into or out of the pipette tip. The utility model adopts a conventional motor, which can realize the shortest distance between the reciprocating motion axis of the pipetting actuator and the vertical line of the mechanism fulcrum, and reduce the harmful overturning caused by the frequent press-in connection of the pipetting actuator and the pipetting head along the axis downward. Moment and fatigue deformation.

Description

An electric pipette

technical field

The utility model relates to a sample adding device, in particular to an electric pipette.

Background technique

In the detection work in the fields of medicine, food, biology, etc., it is necessary to carry out a lot of pre-processing work on biological materials and samples (usually in liquid form). The use of high-throughput automated biological sample pre-processing equipment can be completed in batches in a short time. Pipetting, adding samples, mixing and other operations, the electric pipette is the core technology unit in the biological sample automatic processing system. According to the different pumping and driving methods of electric pipettes, electric pipettes are divided into two types: gas-liquid mixing displacement type and gas displacement type.

The gas-liquid mixing displacement pipette adopts a liquid plunger, and the liquid plunger and the sample liquid are isolated by the air gap reserved in the pipette head. The advantage of the gas-liquid mixing displacement pipette is that the electric reciprocating injection mechanism and the pressure sensor After separation, only one thin tube enters the pipetting actuator, which greatly reduces the design pressure and load of the pipetting actuator components and meets the minimum center distance requirements of the vessel; at the same time, the reciprocating axis of the pipetting actuator and the mechanism fulcrum can be made. The vertical distance is minimized, reducing harmful overturning moments and fatigue deformation of support components due to frequent press-in connections of the pipetting actuator down its axis with the pipette head; The isolation air gap is very small, and the pipetting accuracy is high. The disadvantage is that there is a gas-liquid pipeline pressure system, many components, complex debugging and high maintenance costs; when the room temperature is low, it is easy to cause liquid leakage.

The gas displacement pipette adopts a solid plunger, and the reciprocating motion of the solid plunger is realized by the motor driving the screw or synchronous toothed belt through the coupling or other connecting parts, that is to say, the components such as the electric reciprocating injection mechanism and the pressure sensor are related to the Pipetting actuators are assembled together without complicated pressure pipelines and pump systems, and the structure is clearly structured, which greatly reduces the workload of unit structure installation and debugging. The first existing gas displacement pipette uses a small-diameter, high-speed motor with a reducer to form a blade-type pipetting actuator unit, although it can achieve the shortest distance between the reciprocating axis of the pipetting actuator and the vertical line of the mechanism fulcrum However, the price is extremely expensive, the operation and maintenance costs are high, and the debugging is difficult; the second existing gas displacement pipette uses a conventional motor, which is low in price, low in operation and maintenance costs, and easy to debug, but it is not enough. The disadvantage is that the distance between the reciprocating motion axis of the pipetting actuator and the vertical line of the mechanism fulcrum will become larger, and the harmful overturning moment generated when the pipetting actuator is frequently pressed down with the pipetting head along its axis will become larger. The supporting parts are prone to fatigue deformation.

Utility model content

The purpose of this utility model is to provide an electric pipette, which can not only solve the problem of high price in the prior art using a small-diameter high-speed motor, but also solve the reciprocating motion of the pipetting actuator in the prior art using a conventional motor. The large distance between the axis and the vertical line of the mechanism fulcrum, the large harmful overturning moment and the fatigue deformation caused by the frequent press-fit connection of the pipetting actuator downward along the axis and the pipetting head.

In order to achieve the above purpose, the utility model proposes an electric pipette, which includes: a loading mechanism, including a support frame with a fixed fulcrum, vertically rotatably installed on the support frame and located on the front side of the fixed fulcrum The first screw, the driven pulley connected above the first screw, the driving pulley connected with the driven pulley through the horizontally arranged synchronous belt, and the first pulley coaxially connected with the driving pulley a motor, the first motor is located on the rear side of the fixed fulcrum, and the first motor can drive the first screw to rotate through the driving pulley, the synchronous belt and the driven pulley in sequence; execute a mechanism, located on the front side of the fixed fulcrum, the actuator includes a frame that can slide up and down and is installed on the support frame, and an injection tube that is vertically fixed on the frame and can be plugged with the pipette head , a plunger vertically inserted in the injection pipe, a dislocation slider set above the injection pipe and connected with the plunger, rotatably vertically installed on the frame and dislocated from the a second screw screw connected to the slider, and a second motor located above the second screw rod and connected with the second screw rod, the second motor can drive the second screw rod to rotate, and the first screw rod passes through Rotationally drives the frame to drive the injection tube to move axially, the injection tube is inserted into the pipetting head through axial downward movement, and the second screw drives the dislocation slider to drive the The plunger moves axially, and the plunger draws liquid into or out of the pipetting head through axial reciprocation.

The above electric pipette, wherein the lower end of the injection tube has a plug-in wall that can be inserted into the pipette head, and a perforation is provided on the side wall of the injection tube adjacent to the plug-in wall, The perforation is located above the plug-in wall and below the plunger, the actuator further includes a pressure detection device, and the pressure detection device includes a sampling pipe and a pressure sensor provided on the frame, so One end of the sampling tube is inserted into the perforation and communicated with the injection tube, 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, the buffer is inserted into the end of the injection tube, and the buffer is located below the plunger.

The above-mentioned electric pipette, wherein the actuator further comprises a pipette head withdrawal device, and the pipette head withdrawal device comprises a pressing block which can be axially slid and is sleeved outside the injection tube, and is fixed on the A top rod that is vertically installed on the frame above the pressing block and can move axially, an elastic piece that is sleeved outside the top rod, and an adjusting ring that is fixedly sleeved outside the top rod. The adjusting ring is located above the elastic member, and the adjusting ring and the elastic member are separated by the frame, the upper end of the elastic member is pressed against the frame, and the lower end of the elastic member is pressed against the frame a pressing block, the ejector rod is located under the dislocation slider, and the dislocation slider pushes the ejector rod and the pressing block by moving downwards to the top of the pipetting head that is sleeved on the outside of the injection tube Pressure is applied to make the pipetting head fall off the syringe, and the adjusting ring can bear against the frame when the ejector rod moves down a predetermined distance.

The above electric pipette, 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, and the lower part of the rack is provided with a signal conditioning The signal conditioning board is located under the dislocation slider and above the pressing block, and the signal conditioning board is provided with a plunger position sensor for detecting the position of the plunger and a plunger position sensor for detecting the displacement The pipette head position sensor of the liquid head position, the pipette head position sensor detects the position of the pipette head by detecting the position of the first block, and the plunger position sensor detects the second block by detecting the position of the pipette head. the position of the sheet to detect the position of the plunger.

The electric pipette as described above, wherein the actuator further comprises an optical axis fixed on the frame and parallel to the second screw, a linear bearing arranged in the dislocation slider, and an optical axis arranged in the dislocation slider. The anti-backlash nut in the dislocation slider, the optical axis passes through the linear bearing, the second screw passes through the anti-backlash nut, and is threaded with the dislocation slider through the anti-backlash nut connect.

The above electric pipette, wherein the dislocation slider has a connecting hole coaxially arranged with the plunger, the lower end of the connecting hole has a conical hole whose diameter is gradually expanded from bottom to top, the 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 conical hole, and the diameter of the connecting rod is smaller than that of the cone 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.

The electric pipette as described above, wherein the rack comprises a top rack, a bottom rack located below the top rack, and a side plate connected between the top rack and the bottom rack, the top rack The frame, the side plate and the bottom frame form a sliding space, the second motor is fixed on the top of the top frame, the second screw rod passes through the sliding space, and the upper end of the second screw rod is connected to the top of the top frame. The second motor is connected, the lower end of the second screw is connected with the chassis through a bearing, the dislocation slider is located in the sliding space, the injection tube passes through the chassis, and is connected with the chassis. Bottom frame fixed connection.

The above electric pipette, wherein the support frame is an elongated hollow groove block, the first screw is arranged in the groove block, the front side of the groove block is open, the The rear side plate of the slot block is a vertically arranged connecting plate, the fixed fulcrum is located on the connecting plate, a vertical guide rail is arranged in the slot block, and the side of the rack facing the slot block A guide rail slider and a nut slider are fixed, the guide rail slider extends into the groove block and slides with the guide rail, and the nut slider extends into the groove block and is connected with the first groove block. The screws are threadedly connected, and the first screw drives the frame and the guide slider to slide up and down along the guide rail by rotating the nut slider.

The above electric pipette, wherein, the support frame further comprises a top plate and a bottom plate, the top plate is fixed on the top of the connecting plate, the bottom plate is fixed on the bottom of the connecting plate, and the driving pulley is installed on the The top of the top plate, the top plate extends toward the rear side of the connecting plate to form an extension plate, the driven pulley is installed on the top of the extension plate, and the first motor is inverted and fixed on the extension plate. At the bottom, the upper end of the first screw rod is connected to the top plate through a bearing, and the lower end of the first screw rod is connected to the bottom plate through a bearing.

The features and advantages of the electric pipette of the present utility model are:

1. The electric pipette of the present utility model adopts a conventional motor, which is lower in price compared with the motor with a small diameter and a high rotation speed in the prior art. Because the size of the conventional motor is larger, when arranging, the first motor is placed. On the rear side of the fixed fulcrum, the driving pulley, synchronous belt and driven pulley located above the first screw rod are used to transmit the torque of the first motor to the first screw rod, and the actuator is placed in front of the fixed fulcrum, and the second The motor is placed above the second screw and directly drives the second screw to rotate, so the first motor and the second motor do not occupy too much space between the reciprocating axis of the actuator and the fixed fulcrum, and can realize the reciprocating axis of the actuator and the fixed fulcrum The distance between the vertical lines is minimized, reducing the harmful overturning moment and fatigue deformation caused by the frequent press-fit connection of the actuator down the axis and the pipette head;

2. In the electric pipette of the present invention, the sampling point of the pressure sensor is set at the narrow air gap between the injection cavity and the pipetting head in the injection tube. Because the sampling air gap is very small, under the cooperation of the highly sensitive pressure sensor , when impurities or clots in the liquid block the pipette head, it is easy to detect, effectively improving the sensitivity of pressure detection;

3. In the electric pipette of the present utility model, the pressure block of the pipetting head exit device is directly sleeved outside the injection tube, and the pipette head can be withdrawn by driving the ejector rod and the pressure block to move down through the dislocation slider, and the plunger is removed. As the driving device of the pressing block, the driving device has a simple and compact structure, and does not need to set up a pipette head exit mechanism and a driving electromagnetic component with a complicated structure, thereby reducing the cost;

4. In the electric pipette of the present utility model, the injection tube can be directly connected with the pipetting head to realize the integration of the injection pump and the injection cavity, which not only makes the structure simple and compact, but also lengthens the injection tube and the plunger. Increase the measuring range;

5. The electric pipette of the present utility model has the advantages of simple and compact structure, low price, low transportation and maintenance cost, and easy debugging.

Description of drawings

The following drawings are only intended to illustrate and explain the present invention schematically, and do not limit the scope of the present invention. in:

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

Fig. 2 is the sectional view of the actuator in the utility model;

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

Main component label description:

100. Loading mechanism;

101, support frame; 1011, connecting plate; 1012, top plate; 1013, bottom plate; 1014, extension plate;

102, the first screw; 103, the driven pulley; 104, the timing belt;

105, active pulley; 106, first motor; 107, guide rail; 108, reference position sensor;

109. Fixed fulcrum;

200. Executive agency;

201, rack; 2011, top frame; 2012, bottom frame; 2013, side panel; 2014, installation slot;

2015, through hole; 2016, wire slot; 2017, sliding space;

202, injection tube; 2021, plug-in wall; 2022, perforation; 2023, annular protrusion;

2024, O-ring;

203, plunger; 204, dislocation slider; 205, second screw;

206, second motor; 207, buffer; 208, sampling tube; 209, pressing block; 210, ejector rod;

211, elastic piece; 212, adjustment ring; 213, first top wire; 214, second top wire; 215, first stopper;

216, signal conditioning board; 217, second block; 218, optical axis; 219, connecting rod; 220, ball head;

221, rubber plug; 222, adjusting nut; 223, O-ring; 224, hollow flange;

225, guide rail slider; 226, nut slider; 227, anti-backlash nut;

300, pipetting head.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention will now be described with reference to the accompanying drawings. In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top" , "bottom", "inside", "outside" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that The device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", etc. are used for descriptive purposes only, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second", etc., may expressly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

Except for the directions indicated by separate definitions, the “front side” referred to in this document refers to the left side shown in FIG. 1 of the present utility model, and the “rear side” refers to the right side shown in FIG. 1 of the present utility model. "Up", "down", "vertical", "horizontal" and other directions are all based on the up, down, vertical, horizontal and other directions shown in FIG. 1 of the present utility model, and are described together here.

As shown in FIG. 1 , FIG. 2 and FIG. 3 , the present invention proposes an electric pipette, which can be installed on a work frame. The electric pipette includes a loading mechanism 100 for loading a pipetting head 300 and a loading mechanism for The actuator 200 for sucking and discharging liquid, wherein the pipetting head 300 is a standardized pipetting head with a volume of 50 microliters to 1000 microliters, and the pipetting head 300 is a disposable item, usually made of plastic, which is a consumable item and is completed once The liquid is disposed of and discarded; of which,

The loading mechanism 100 includes a support frame 101 with a fixed fulcrum 109 (or referred to as a mechanism fulcrum), or in other words, the connection between the support frame 101 and the work frame forms a fixed fulcrum for supporting the electric pipette;

The loading mechanism 100 also includes a first screw 102 vertically rotatably mounted on the support frame 101 and located on the front side of the fixed fulcrum 109, a driven pulley 103 connected above the first screw 102, and a synchronous belt 104 arranged horizontally through The driving pulley 105 connected to the driven pulley 103 and the first motor 106 coaxially connected to the driving pulley 105 , the first motor 106 , the driving pulley 105 and the driven pulley 103 are all mounted on the support frame 101 , the first motor 106 is located on the rear side of the fixed fulcrum 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 turn, and the first motor 106 has an encoder;

The actuator 200 is located on the front side of the fixed fulcrum 109. The actuator 200 includes a frame 201 that can slide up and down and is installed on the support frame 101, and a syringe 202 that is vertically fixed on the frame 201 and can be plugged with the pipetting head 300. , the plunger 203 vertically inserted in the injection tube 202, the dislocation slider 204 arranged above the injection tube 202 and connected with the plunger 203, and vertically installed on the frame 201 and connected with the dislocation slider 204 in a rotatable manner. The threaded second screw 205 and the second motor 206 located above the second screw 205 and connected to the top of the second screw 205, an injection cavity is formed in the injection tube 202, and the second motor 206 can drive the second screw 205 to rotate, The second motor 206 is provided with an encoder, the first screw 102 drives the injection tube 202 to move axially upward or axially downward by rotating the drive frame 201, and the injection tube 202 is inserted into the pipetting head 300 through the axial downward movement. Thereby, the pipette head 300 is loaded, and the second screw 205 drives the dislocation slider 204 to drive the plunger 203 to move axially upward or downward. The plug 203 discharges the liquid in the pipetting head 300 by moving downward in the axial direction, so as to realize the suction and discharge of the liquid.

When in use, install the electric pipette on the work frame so that the electric pipette can be suspended. Various containers or testing equipment can be placed under the electric pipette, and the pipetting head 300 can be used to complete pipetting, adding samples, etc. operate.

In the electric pipette of the present invention, the first motor 106 and the second motor 206 used are common motors (conventional motors), and the price is low. Placed on the rear side of the fixed fulcrum 109 (ie the mechanism fulcrum), the driving pulley 105, the synchronous belt 104 and the driven pulley 103 located above the first screw 102 are used to transmit the torque of the first motor 106 to the first screw 102, and The actuator 200 is placed in front of the fixed fulcrum 109, and the second motor 206 is placed above the second screw 205 to directly drive the second screw 205 to rotate, so the first motor 106 and the second motor 206 will not occupy too much of the actuator 200. The space between the reciprocating axis (ie the central axis of the second motor 206 and the second screw 205) and the fixed fulcrum 109 can minimize the vertical distance between the reciprocating axis of the actuator 200 and the fixed fulcrum 109, reducing the Harmful overturning moment and fatigue deformation generated when the mechanism 200 is frequently press-fitted with the pipetting head 300 down the axis;

In addition, by placing the larger first motor 106 behind the fixed fulcrum 109, the left and right widths of the portion of the electric pipette located in front of the fixed fulcrum 109 can be reduced;

In addition, since the syringe 202 can be directly plugged with the pipette head 300, the syringe pump and the injection cavity are combined into one, which not only makes the structure simple and compact, but also lengthens the syringe 202 and the plunger 203, thereby increasing the range of the measuring range. .

As shown in FIG. 2 , in one embodiment, the actuator 200 further includes a tubular buffer 207 , the buffer 207 is inserted into the end of the injection tube 202 , that is, the end of the injection cavity, and the buffer 207 is located in the plunger 203 Below, the gas in the buffer 207 is used as a gas plunger, and the inner diameter of the buffer 207 is smaller than the inner diameter of the injection cavity, so as to meet the requirement of high precision in a small range.

As shown in FIG. 2 , in one embodiment, the lower end of the injection tube 202 has a plug wall 2021 that can be inserted into the pipette head 300 , the plug wall 2021 is sealedly connected with the pipette head 300 , and the side wall of the injection tube 202 is There is a through hole 2022 adjacent to the insertion wall 2021, the through hole 2022 is located above the insertion wall 2021, and is located 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 It also includes a pressure detection device, the pressure detection device includes a sampling tube 208 and a pressure sensor provided on the frame 201, one end of the sampling tube 208 is inserted into the through hole 2022 and communicated with the injection tube 202, and the other end of the sampling tube 208 is connected with the pressure sensor, The sampling tube 208 is an elongated tube made of metal material, for example, the pressure sensor is a micro-pressure sensor with high sensitivity.

In this embodiment, the sampling point of the pressure sensor is set at the narrow air gap between the injection cavity and the pipetting head 300 in the injection tube 202. Since the sampling air gap is very small, with the cooperation of the highly sensitive pressure sensor, when the liquid is When impurities or clots in the pipette block the pipette head 300, it is easy to detect, effectively improving the sensitivity of pressure detection; the pressure detection with high signal-to-noise ratio can also realize bubble artifact identification and liquid level detection, which fully meets the main requirements in liquid processing. Pressure data detection.

As shown in FIG. 2 , specifically, the outer wall surface of the plug-in wall 2021 has two annular protrusions 2023 arranged up and down, and the cross-sectional shape of the annular protrusions 2023 is arc-shaped. During insertion, the annular protrusion 2023 is in contact with the inner wall 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 injection tube 202 and the pipetting head 300 . When the pipette head 300 is loaded, the first motor 106 drives the first screw 102 to rotate, and the first screw 102 drives the actuator 200 to move downward through the rotation until the two annular protrusions 2023 of the insertion wall 2021 of the syringe 202 are squeezed. Press in the pipette head 300 to complete the operation of loading the pipette head 300 .

As shown in FIG. 1 , FIG. 2 , and FIG. 3 , in one embodiment, the actuator 200 further includes a pipette head withdrawal device, and the pipette head withdrawal device includes a pressing block sleeved outside the injection tube 202 that can slide axially 209. The ejector rod 210, which is fixed above the pressing block 209 and can be moved axially, is vertically installed on the frame 201, the elastic member 211 is sleeved outside the ejector rod 210, and the adjusting ring is fixedly sleeved outside the ejector rod 210. 212, for example, the elastic member 211 is a spring, the adjusting ring 212 is located above the elastic member 211, and the adjusting ring 212 and the elastic member 211 are separated by the frame 201, the upper end of the elastic member 211 abuts the frame 201, and the lower end of the elastic member 211 The pressing block 209, the ejector rod 210 is located under the dislocation slider 204, and the dislocation slider 204 pushes the ejector rod 210 and the pressing block 209 by moving downward to exert pressure on the top of the pipetting head 300 sheathed outside the syringe 202, so that the displacement The liquid head 300 is dropped from the injection tube 202 , and the adjusting ring 212 can withstand the frame 201 when the ejector rod 210 moves down a predetermined distance, so as to limit the ejector rod 210 and the pressing block 209 .

In this embodiment, the pressure block 209 of the pipette head exit device is directly sleeved outside the injection tube 202, and the ejector rod 210 and the pressure block 209 are driven downward by the dislocation slider 204 to withdraw the pipette head 300, and the plunger is directly removed. The driving device of 203 (ie, the dislocation slider 204, the second screw 205 and the second motor 206) is used as the driving device of the pressing block 209, and the structure is simple and compact. cost.

As shown in FIG. 2 , specifically, the side wall of the adjusting ring 212 is provided with a first top wire 213 along the radial direction, and the first top wire 213 is threadedly connected with the adjusting ring 212 and bears against the side wall of the top rod 210 to prevent Fix the adjustment ring 212 and the ejector rod 210 together, when the position of the adjustment ring 212 on the ejector rod 210 needs to be adjusted, loosen the first ejector wire 213, move the adjustment ring 212 up and down, and move the adjustment ring 212 to an appropriate position , and then tighten the first top wire 213 to fix the adjusting ring 212 and the top rod 210 together, and the adjustment is very convenient;

The side wall of the pressing block 209 is provided with a second top wire 214 along the radial direction. The second top wire 214 is threadedly connected with the pressing block 209 and bears against the side wall of the top rod 210 to fix the pressing block 209 and the top rod 210 Together, when it is necessary to adjust the relative position of the ejector bar 210 and the pressing block 209, loosen the second ejector wire 214, move the ejector bar 210 up and down, move the ejector bar 210 to an appropriate position, and then tighten the second ejector bar 214 , the top rod 210 and the pressing block 209 are fixed together, and the adjustment is very convenient.

As shown in FIG. 2 , further, the top of the pressing block 209 is further provided with a first blocking piece 215 . When the pressing block 209 pushes the pipetting head 300 downward, the first blocking piece 215 can move down with the pressing block 209 , and the machine The lower part of the rack 201 is provided with a signal conditioning plate 216, the signal conditioning plate 216 is located above the pressing block 209, and the signal conditioning plate 216 is provided with a pipetting head position sensor for detecting the position of the pipetting head 300. The position of a blocking plate 215 is used to detect the position of the pipetting head 300 , and the signal conditioning board 216 can transmit the position signal of the pipetting head 300 to the computer. For example, the pipette head position sensor is a photoelectric sensor.

As shown in FIG. 2 , further, the bottom of the dislocation slider 204 is further provided with a second blocking piece 217 . When the dislocation slider 204 drives the plunger 203 to move up and down, the second blocking piece 217 can move up and down with the dislocation slider 204 . The signal conditioning plate 216 is located under the dislocation slider 204 , and a plunger position sensor for detecting the position of the plunger 203 is provided on the signal conditioning plate 216 . The plunger position sensor detects the position of the plunger 203 by detecting the position of the second blocking piece 217 . , the signal conditioning board 216 can transmit the position signal of the plunger 203 to the computer. For example, the plunger position sensor is a photoelectric sensor.

As shown in FIG. 1 , FIG. 2 , and FIG. 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 , and an optical axis 218 disposed in the dislocation slider 204 . The linear bearing, the anti-backlash nut 227 arranged in the dislocation slider 204, and the optical axis 218 are used as the slide rail of the dislocation slider 204 to guide the dislocation slider 204 to slide. For example, there are two optical axes 218 and two optical axes. 218 are arranged side by side and spaced apart. There are two linear bearings. Each optical axis 218 passes through each linear bearing respectively. When the second motor 206 drives the second screw 205 to rotate, the anti-backlash nut 227 drives the dislocation slider 204 to slide up and down along the optical axis 218 .

As shown in FIG. 2, in one embodiment, the plunger 203 is flexibly connected to the dislocation slider 204. Specifically, the dislocation slider 204 has a connecting hole coaxially disposed with the plunger 203, and the lower end of the connecting hole has a diameter The conical hole gradually expands from bottom to top, the top of the plunger 203 is connected with a connecting rod 219, the top of the connecting rod 219 is connected with a ball head 220, the ball head 220 is located in the connecting hole and sits on the conical hole, and the connecting rod 219 The diameter of the connecting rod is smaller than the minimum diameter of the conical hole, so that the connecting rod 219 can pass through the conical hole. A rubber plug 221 is fixed in the connecting hole. The use of such a connection structure not only makes the plunger 203 and the dislocation slider 204 relatively fixed in the axial direction, but also allows the plunger 203 to be shifted to the left and right while moving axially. Compared with the rigid connection, the plunger 203 Not easy to damage.

As shown in FIG. 2 , further, the plunger 203 is slidably and sealedly connected to the top end of the injection tube 202 . Specifically, a cap-shaped adjusting nut 222 is sleeved on the outer side of the top end of the injection tube 202 , and the plunger 203 can axially slide through it. Adjusting nut 222. An O-ring 223 is sandwiched between the top of the injection tube 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. The O-ring 223 and the adjusting nut 222 can connect the injection tube 202 and the plunger 203 in a sliding and sealing manner to realize dynamic sealing.

As shown in FIG. 1 and FIG. 3 , in a specific implementation manner, the rack 201 includes a top rack 2011 , a bottom rack 2012 located below the top rack 2011 , and a side plate connected between the top rack 2011 and the bottom rack 2012 In 2013, the top frame 2011 and the bottom frame 2012 are both block-shaped, the top frame 2011, the side plates 2013 and the bottom frame 2012 enclose a sliding space 2017, the second motor 206 is fixed on the hollow flange 224 on the top of the top frame 2011, the second The 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 to the second motor 206, and the lower end of the second screw 205 is connected to the bottom frame 2012 through a bearing, for example, the second screw 205 is connected to the second motor 206 The optical axis 218 passes 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, and the dislocation slider 204 is located in the sliding space 2017, The injection tube 202 passes through the bottom frame 2012 and is fixedly connected with the bottom frame 2012. The upper end of the injection tube 202 extends into the sliding space 2017; In the space 2017, the adjusting ring 212 can press against the top surface of the bottom frame 2012 when the top rod 210 moves downward by a preset distance, the elastic member 211 is located below the bottom frame 2012, and the upper end of the elastic member 211 presses against the bottom surface of the bottom frame 2012;

The bottom of the chassis 2012 is provided with a mounting slot 2014, the signal conditioning board 216 is disposed in the mounting slot 2014 at the bottom of the chassis 2012, and the bottom chassis 2012 is further provided with a through hole 2015 that penetrates up and down, and the through hole 2015 is adjacent to the mounting slot 2014. The first blocking piece 215 and the second blocking piece 217 are aligned up and down with the through hole 2015 , and the first blocking piece 215 can extend upward into the through hole 2015 to be received by the pipetting head on the signal conditioning plate 216 The position sensor detects that the second blocking piece 217 can extend downward into the through hole 2015 to be detected by the position sensor of the plunger 203 on the signal conditioning board 216 .

In the specific arrangement, for example, the injection tube 202, the ejector rod 210, the optical axis 218 and the second screw 205 are arranged in sequence toward the direction close to the support frame 101, the two optical axes 218 are arranged side by side, the first blocking piece 215 and the second screw 218 are arranged side by side. The blocking piece 217 is located on the rear side of the top rod 210 and the front side of the second screw 205, the signal conditioning plate 216 is located on the rear side of the first blocking piece 215 and the second blocking piece 217, the side plate 2013 of the rack 201 is located on the rear side of the bottom frame 2012, The signal conditioning board 216 is located under the side board 2013, and the side board 2013 is provided with a wire groove 2016. The wire groove 2016 is connected to the installation groove 2014 where the signal conditioning board 216 is located. The signal line passes through the wire groove 2016, and one end of the signal line is connected to the signal conditioning board The board 216 is connected, the other end of the signal line is connected with the second motor 206 , the signal conditioning board 216 transmits the position signal of the plunger 203 to the second motor 206 through the signal line, and the second motor 206 is controlled according to the position signal of the plunger 203 The rotation of the second screw 205 controls the initial position of the dislocation slider 204 , and then controls the position of the plunger 203 .

As shown in FIG. 1 and FIG. 3 , in a specific implementation manner, the support frame 101 is an elongated hollow slot block, the front side of the slot block is open, and the rear side plate 2013 of the slot block is vertically arranged The connecting plate 1011, the fixed fulcrum 109 is located on the connecting plate 1011, specifically, the work frame is located on the rear side of the connecting plate 1011, and the connection between the rear side of the connecting plate 1011 and the work frame forms a fixed fulcrum 109, and the groove block is provided with a vertical The guide rail 107, for example, the guide rail 107 is fixed on the front side of the connecting plate 1011, the first screw 102 is arranged in the groove block, the side of the rack 201 facing the groove block is fixed with a guide rail slider 225 and a nut slider 226, the guide rail The slider 225 extends into the groove block and slides with the guide rail 107 . The nut slider 226 extends into the groove block and is threadedly connected with the first screw rod 102 . The nut slider 226 drives the frame 201 when the first screw rod 102 rotates. And the guide rail slider 225 slides up and down along the guide rail 107 . In this embodiment, the combined structure of the support frame 101 and the rack 201 is simple and compact.

For example, there are two guide rail sliders 225, the two guide rail sliders 225 are arranged at intervals up and down, the upper guide rail slider 225 is fixed on the rear side of the top frame 2011 of the rack 201, and the lower guide rail slider 225 is fixed on the rack 201. On the rear side of the connecting plate 1011 , the nut slider 226 is located between the two guide rail sliders 225 , and the nut slider 226 is fixed on the lower guide rail slider 225 . Preferably, the nut slider 226 is an anti-backlash nut, and the frame 201 and the guide rail slider 225 have an integrated structure with high structural strength.

As shown in FIG. 2 , in a specific embodiment, the groove 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 , and the driving pulley 105 is installed on the top plate 1012 The top plate 1012 extends toward the rear side of the connecting plate 1011 to form an extension plate 1014, the driven pulley 103 is installed on the top of the extension plate 1014, the first motor 106 is inverted and fixed on the bottom of the extension plate 1014, and the upper end of the first screw 102 It is connected with the top plate 1012 through a bearing, and the lower end of the first screw rod 102 is connected with the bottom plate 1013 through a bearing. Specifically, both the top plate 1012 and the bottom plate 1013 are flanges for easy connection.

As shown in FIG. 2 , further, 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 under the top plate 1012 of the slot block, and is connected to the The top plate 1012 is adjacent, and the reference position sensor 108 is located above the two guide rail sliders 225 . When the rack 201 slides up and down along the guide rail 107 , the reference position sensor 108 can detect the position of the rack 201 .

When pipetting with the electric pipette of the present invention, in order to avoid cross-contamination of the liquid, the liquid cannot enter the injection cavity in the injection tube 202, nor into the buffer 207, but only in the pipetting head 300. The size of the range of liquid processing depends on the volume of the pipetting head 300 , and the size of the range of the electric pipette depends on the volume of the plunger 203 .

Before liquid suction, the position of the plunger 203 needs to be initialized. Specifically, the dislocation slider 204 drives the plunger 203 to move downward. Once the signal conditioning board 216 detects the position of the second blocking piece 217 on the dislocation slider 204, that is, The 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 this position is recorded as the initial position (reset) of the dislocation slider 204 and the plunger 203. , the plunger 203 starts to move upward from the initial position;

When the pipetting head 300 needs to be withdrawn after completing a pipetting operation, the dislocation slider 204 is allowed to overtravel and descend by a few millimeters. The pressing block 209 moves downward, withdraws the pipetting head 300, and re-detects the initial position (reset) before the next pipetting.

The above descriptions are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the protection scope of the present invention. And it should be noted that each component of the present utility model is not limited to the above-mentioned overall application, and each technical feature described in the specification of the present utility model can be used alone or in combination according to actual needs. Therefore, Of course, the present invention covers other combinations and specific applications related to the inventive point of the present invention.

Claims (10)

1. an electric pipette, is characterized in that, described electric pipette comprises: The loading mechanism includes a support frame with a fixed fulcrum, a first screw rod rotatably vertically installed on the support frame and located on the front side of the fixed support point, a driven pulley connected above the first screw rod, A driving pulley connected to the driven pulley through a horizontally arranged synchronous belt, and a first motor coaxially connected to the driving pulley, the first motor is located behind the fixed fulcrum, the first motor A motor can drive the first screw to rotate through the driving pulley, the synchronous belt and the driven pulley in sequence; The actuator is located on the front side of the fixed fulcrum, and the actuator includes a frame that can slide up and down and is installed on the support frame, and an injection that is vertically fixed on the frame and can be plugged with a pipetting head tube, a plunger vertically inserted in the injection tube, a dislocation slider set above the injection tube and connected with the plunger, vertically rotatably mounted on the frame and connected to the A second screw screw connected with the dislocation slider, and a second motor located above the second screw and connected with the second screw, the second motor can drive the second screw to rotate, the first screw The frame is driven to rotate to drive the syringe to move axially, the syringe to be inserted into the pipetting head through axial downward movement, and the second screw drives the dislocation slider to drive the The plunger moves axially, and the plunger draws liquid into or out of the pipetting head through axial reciprocation. 2 . The electric pipette according to claim 1 , wherein the lower end of the injection tube has a plug-in wall that can be inserted into the pipette head, and the side wall of the injection tube is adjacent to the plug. 3 . The connecting wall is provided with a perforation, the perforation is located above the inserting wall and below the plunger, and the actuator also includes a pressure detection device, the pressure detection device includes a sampling tube and a A pressure sensor on the rack, one end of the sampling tube is inserted into the perforation and communicated with the injection tube, and the other end of the sampling tube is connected with the pressure sensor. 3. The electric pipette of claim 1, wherein the actuator further comprises a tubular buffer, the buffer is inserted into the end of the syringe, and the buffer is located at the below the plunger. 4 . The electric pipette according to claim 1 , wherein the actuator further comprises a pipette head withdrawal device, and the pipette head withdrawal device comprises an axially slidable sleeve outside the injection tube. 5 . a pressing block, a top rod that is fixed above the pressing block and can be moved axially and is vertically installed on the frame, an elastic piece that is sleeved outside the top rod, and a fixed sleeve that is sleeved on the top rod An outer adjusting ring, the adjusting ring is located above the elastic member, and the adjusting ring and the elastic member are separated by the frame, the upper end of the elastic member is pressed against the frame, and the elastic member is The lower end of the piece abuts the pressing block, the top rod is located under the dislocation slider, and the dislocation slider pushes the top rod and the pressing block to be sleeved on the outside of the injection tube by moving downward. The top of the pipetting head exerts pressure to make the pipetting head fall off the injection tube, and the adjusting ring can withstand the rack when the ejector rod moves down a preset distance. 5. The electric pipette according to claim 4, 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, and the machine is further provided with a second blocking piece. The lower part of the frame is provided with a signal conditioning plate, the signal conditioning plate is located under the dislocation slider and above the pressing block, and 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 stopper, the plunger position sensor The position of the plunger is detected by detecting the position of the second stopper. 6 . The electric pipette according to claim 1 , wherein the actuator further comprises an optical axis fixed on the frame and parallel to the second screw, which is arranged on the dislocation slider. 7 . The linear bearing inside and the anti-backlash nut arranged in the dislocation slider, the optical axis passes through the linear bearing, the second screw passes through the anti-backlash nut, and passes through the anti-backlash nut threadedly connected with the dislocation slider. 7 . The electric pipette according to claim 1 , wherein the dislocation slider has a connecting hole coaxially arranged with the plunger, and the lower end of the connecting hole has a diameter that gradually expands from bottom to top. 8 . 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 conical hole, the connecting rod The diameter of the 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 rack comprises a top rack, a bottom rack located below the top rack, and a bottom rack connected to the top rack and the The side plate between the bottom frames, the top frame, the side plate and the bottom frame form a sliding space, the second motor is fixed on the top of the top frame, and the second screw passes through the In 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 chassis through a bearing, the dislocation slider is located in the sliding space, and the injection A tube passes through the base frame and is fixedly connected to the base frame. 9. The electric pipette according to any one of claims 1 to 7, wherein the support frame is an elongated hollow groove block, and the first screw rod is arranged in the groove block, The front side of the slot block is open, the rear side plate of the slot block is a vertically arranged connecting plate, the fixed fulcrum is located on the connecting plate, and a vertical guide rail is arranged in the slot block, so the A guide rail slider and a nut slider are fixed on the side of the frame facing the slot block, the guide rail slider extends into the slot block and slides with the guide rail, and the nut slider extends into the slot block. The groove block is threadedly connected with the first screw rod, and the first screw rod drives the frame and the guide rail slider to slide up and down along the guide rail by rotating the nut slider. 10. The electric pipette of claim 9, wherein the support frame further comprises a top plate and a bottom plate, the top plate is fixed on the top of the connecting plate, and the bottom plate is fixed on the bottom of the connecting plate, The driving pulley is installed on the top of the top plate, the top plate extends toward the rear side of the connecting plate to form an extension plate, the driven pulley is installed on the top of the extension plate, and the first motor is inverted is fixed on the bottom of the extension plate, the upper end of the first screw rod is connected with the top plate through a bearing, and the lower end of the first screw rod is connected with the bottom plate through a bearing.

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