A device for precise quantitative pipetting and liquid preparation

Abstract

The present invention relates to a device for precise quantitative pipetting and liquid dispensing, which comprises a liquid processing module and a quantitative loop liquid sampling module. The liquid processing module includes a sampling needle, a lifting motor, a rotating motor and a centering mechanism. The centering mechanism is used for placing a liquid container. The sampling needle sucks the solution from the liquid container. The lifting motor controls the up-and-down movement of the sampling needle through a lead screw, and the rotating motor controls the horizontal movement of the sampling needle through a swing arm. The quantitative loop liquid sampling module includes two switching valves and a plurality of quantitative loops. A plurality of outlets of the first switching valve are respectively connected to a clean air source and a plurality of quantitative loops, and the inlet is connected to the sampling needle. A plurality of outlets of the second switching valve are respectively connected to a first discharge port and a plurality of quantitative loops, and the inlet is connected in parallel to a liquid pump and a clean air source. The inlet of the cleaning pool is connected to a cleaning liquid pipeline. The inlet of the drying pool is connected to a clean air source. By switching through the switching valve and the conversion of the sampling needle among the liquid container, the cleaning pool and the drying pool, quantitative sampling, cleaning of each passage, liquid discharge and drying are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of experimental configuration solutions and liquid extraction, and particularly relates to a device for precise quantitative pipetting and solution preparation. Background Art

[0002] Quantitatively configuring solutions and quantitatively extracting solutions are very important and frequently occurring basic experimental operations. They are the basic operations for many detection and reaction experiments, especially in the detection field. For example, in the field of studying soil heavy metal pollution, it is necessary to dissolve the pollutants in a large number of collected soil samples, configure solutions, quantitatively extract liquids, and then analyze and detect the obtained solutions to determine the content of various heavy metal pollutants in the soil. Currently, the pretreatment of soil samples is to put the soil into distilled water or other solvents, fully dissolve the heavy metal pollutants to be measured, and then filter out the solid soil to obtain a solution containing heavy metals. This solution is used as the raw material liquid. Subsequently, when preparing solutions or directly sampling the raw material liquid, a peristaltic pump is generally used for pipetting. The peristaltic pump transports liquids by squeezing a hose, and the elastic deformation and wear of the hose will affect the pipetting accuracy and repeatability. Moreover, pipetting usually relies on manual operation, which has problems and limitations such as complex operation, insufficient accuracy, low efficiency, and safety. In addition, there is also a quantitative pipetting method that uses a switching valve and a pump to transfer liquids into a metering loop, but it cannot solve the problem of liquid accumulation in the front and rear pipelines of the metering loop, and the pipetting accuracy is much lower than the accuracy of the metering loop. In addition, the existing syringe pump designs are mainly used for pipetting single sample liquids, and the inner wall of its hose may retain liquids, resulting in cross-contamination or sample loss. It is not suitable for simultaneously processing multiple sample liquids and has poor compatibility. Summary of the Invention

[0003] In view of the above problems, the present invention provides a device for precise quantitative pipetting and solution preparation, including a liquid processing module and a metering loop liquid extraction module. The liquid processing module includes a sampling needle, a lifting motor, a rotating motor, a cleaning pool, a drying pool, and at least one centering mechanism. The centering mechanism is used to place a liquid container. The sampling needle sucks the solution from the liquid container. The lifting motor controls the up and down movement of the sampling needle through a lead screw, and the rotating motor controls the horizontal movement of the sampling needle through a swing arm.

[0004] The metering loop liquid extraction module includes a first switching valve, a second switching valve, and several metering loops. The several outlets of the first switching valve are respectively connected to a clean air source and several metering loops, and the inlet is connected to the sampling needle. The several outlets of the second switching valve are respectively connected to a first discharge port and several metering loops, and the inlets are connected in parallel to a liquid pump and a clean air source. The inlet of the cleaning pool is connected to a cleaning liquid pipeline, and the outlet is connected to a second discharge port. The inlet of the drying pool is connected to a clean air source, and the outlet is connected to a third discharge port. Through the switching of the switching valve and the conversion work of the sampling needle among the liquid container, the cleaning pool, and the drying pool, quantitative loop sampling, cleaning of each passage, liquid discharge, and drying are realized.

[0005] Optionally, the device for precise quantitative pipetting and liquid dispensing includes a main chassis, which is divided into two regions by a middle main frame;

[0006] The middle main frame includes a base frame, a moving cross bar, and two vertical track bars. The lifting motor is arranged on the base frame. The track bars are respectively arranged at both ends of the base frame, and the track bars are perpendicular to the base frame; both ends of the moving cross bar are slidably connected to the track bars, and the rotating motor is arranged on the moving cross bar.

[0007] Further optionally, the top rotating shaft of the lifting motor is connected to the bottom end of the lead screw, the top end of the lead screw is rotatably connected to the top plate of the main chassis, the lead screw passes through the moving cross bar. When the lifting motor drives the lead screw to rotate forward or backward, the moving cross bar rises or falls along the spiral thread of the lead screw, thereby driving the rotating motor, the swing arm, and the sampling needle to move up and down.

[0008] Optionally, a vertical hollow rotating shaft is provided at the center of the rotating motor. The hollow vertical shaft passes through the rotating motor. The bottom of the hollow rotating shaft is connected to a synchronous pulley, and the synchronous pulley rotates synchronously with the hollow rotating shaft; the top of the hollow rotating shaft is connected to one end of the swing arm, and the other end of the swing arm is suspended and connected to the top of the sampling needle. The swing arm is horizontally arranged, and the swing arm drives the sampling needle to make a circular motion with the hollow rotating shaft as the center and the length of the swing arm as the radius.

[0009] Further optionally, the sampling needle is a slender hollow tube capable of transporting liquid; the top end of the sampling needle is connected to an infusion tube, and the infusion tube extends along the swing arm to the hollow rotating shaft, then extends along the hollow rotating shaft and the synchronous pulley, and finally passes through the synchronous pulley and is connected to the inlet of the first switching valve to input the sampled liquid into the first switching valve.

[0010] Optionally, the centering mechanism includes, from top to bottom, a plurality of vertical clamping jaws, a support plate, a cam plate, a plurality of slideways, and a base plate. The cam plate and the support plate are both provided with a plurality of hollow slots corresponding to the clamping jaws, so that the clamping jaws can pass through the cam plate and the support plate; the slideways are arranged on the base plate, and the clamping jaws correspond to the slideways one by one. The bottom of the clamping jaw is slidably connected to the slideway through a slider, and any one slider is connected to a cylinder. The cylinder can drive the clamping jaw to move back and forth along the corresponding slideway, and the movement of the clamping jaw can drive the cam plate to rotate, and the cam plate can further drive other clamping jaws to move back and forth along their respective corresponding slideways, so that all the clamping jaws can approach or move away from the liquid container at the center of the support plate, realizing the action of clamping or loosening the liquid container.

[0011] Further optionally, the top of the cam shaft is fixedly connected to the center of the cam plate, the cam shaft passes downward through the base plate, the bottom of the cam shaft is rotatably connected to the bottom plate below the base plate, and corresponding bearings are arranged outside the cam shaft, so that the cam plate can rotate.

[0012] Further optionally, a plurality of downwardly recessed chutes are provided on the upper surface of the substrate. One end of each chute points to the center of the substrate, and the other end extends to the outer edge of the substrate. The plurality of chutes are evenly distributed around the substrate in a radial pattern;

[0013] The pallet is provided with a plurality of first hollow grooves. One end of each first hollow groove points to the center of the pallet, and the other end points to the outside of the pallet. The plurality of first hollow grooves are evenly distributed around the pallet in a radial pattern, and the positions of the first hollow grooves correspond to those of the chutes one by one.

[0014] Further optionally, the cam plate is evenly provided with a plurality of second hollow grooves. The starting end of each second hollow groove points to the center of the cam plate, and the ending end points to the outside of the cam plate; the radius of the cam plate where the starting end of the second hollow groove is located is the corresponding radius, and the angle between the second hollow groove and its corresponding radius is the rotation angle. The rotation angles of each second hollow groove are the same, so that the plurality of second hollow grooves are arranged in a spiral rotation form.

[0015] Optionally, the inlet of the first switching valve is connected to the top end of the sampling needle through an infusion tube, and can output the taken liquid from the first switching valve. The first switching valve, the infusion tube and the sampling needle form a front-end passage;

[0016] One outlet of the first switching valve is connected to a clean air source, and can input clean air into the front-end passage to blow out the residual liquid in the front-end passage into the cleaning pool;

[0017] The other outlets of the first switching valve are respectively connected to one end of a quantitative loop. The other end of the quantitative loop is connected to the outlet of the second switching valve. By switching the outlets of the two switching valves and using different quantitative loops, the cumulative error caused by using a single quantitative loop is avoided, and the pipetting accuracy is reduced.

[0018] Further optionally, the inlet of the second switching valve is connected to opening one of a three-way valve. Opening two of the three-way valve is connected to a liquid pump, and opening three of the three-way valve is connected to a clean air source; one outlet of the second switching valve is connected to a first discharge port. The passage between the three-way valve, the second switching valve and up to the first discharge port forms a rear-end passage. The clean air source can input clean air into the rear-end passage to blow out the residual liquid in the rear-end passage from the first discharge port; the liquid pump serves as a power source and can suck liquid samples or cleaning liquid into the front-end passage, the pipelines of each quantitative loop and the rear-end passage through the sampling needle;

[0019] After the sampling needle takes liquid for a certain quantitative loop, the sampling needle is then moved to the liquid container or sample tube of another centering mechanism, and the clean air source can push out the sample liquid in the quantitative loop to achieve quantitative pipetting.

[0020] Optionally, a constant volume mechanism is further provided inside the main chassis. The constant volume mechanism includes a first infrared sensor, a second infrared sensor, a first turntable, two first support rods, and a liquid adding funnel. The two infrared sensors are arranged one above the other on the base frame and are respectively used to indicate the upper limit of large-flow liquid inlet and the fine constant volume limit. The first support rod is horizontally arranged, the first turntable is vertically arranged, one end of the first support rod is connected to the first turntable, and the other end clamps the liquid adding pipe. The two first support rods are respectively located at opposite positions of the first turntable. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of the precision quantitative pipetting and liquid dispensing device;

[0022] Figure 2 is Figure 1 a top view schematic diagram of;

[0023] Figure 3 is a schematic diagram (one) of the centering mechanism;

[0024] Figure 4 is a schematic diagram (two) of the centering mechanism;

[0025] Figure 5 is a schematic diagram of the substrate;

[0026] Figure 6 is a schematic diagram of the cam plate;

[0027] Figure 7 is a top view schematic diagram of the centering mechanism;

[0028] Figure 8 is a schematic diagram of the quantitative ring liquid extraction module;

[0029] Figure 9 is a schematic diagram of the vertical track part;

[0030] Figure 10 is a schematic diagram of the constant volume mechanism;

[0031] Figure 11 is a side view schematic diagram of the constant volume mechanism;

[0032] Figure 12 is a schematic diagram of the mixer;

[0033] Figure 13 is a side view schematic diagram of the mixer.

[0034] In the attached drawings, 1 is a sampling needle, 2 is a lifting motor, 3 is a rotating motor, 4 is a cleaning pool, 5 is a drying pool, 6 is a lead screw, 7 is a swing arm, 8 is a base frame, 9 is an orbital rod, 10 is a moving cross bar, 11 is a secondary moving cross bar, 12 is a hollow rotating shaft, 13 is a synchronous pulley, 14 is an infusion tube, 15 is a jaw, 16 is a support plate, 17 is a cam plate, 18 is a slideway, 19 is a substrate, 20 is a cylinder, 21 is a cam rotating shaft, 22 is a first hollow groove, 23 is a second hollow groove, 24 is a first turntable, 25 is a second turntable, 26 is a first support rod, 27 is a second support rod, 28 is a liquid adding funnel, 29 is a vertical orbital part, 30 is a first infrared emitter, 31 is a second infrared emitter, 32 is a first slide rail, 33 is a second slide rail, 34 is a clamping part;

[0035] A is a first switching valve, B is a second switching valve, C is a first discharge outlet, D is a second discharge outlet, E is a third discharge outlet, P is a liquid pump, V is a three-way valve, N is a cleaning liquid pipeline,

[0036] The first switching valve has 7 outlets, which are respectively denoted as A1, A2, A3, A4, A5, A6, A7; the second switching valve has 7 outlets, which are respectively denoted as B1, B2, B3, B4, B5, B6, B7; 5 quantitative loops are respectively denoted as G1, G2, G3, G4, G5; 3 clean air sources are respectively denoted as F1, F2, F3. Detailed implementation mode

[0037] This embodiment provides a device for precise quantitative pipetting and liquid dispensing, as Figures 1-13 shown, including a liquid processing module and a quantitative loop liquid extraction module. The liquid processing module includes a sampling needle 1, a lifting motor 2, a rotating motor 3, a cleaning pool 4, a drying pool 5 and at least one centering mechanism. The centering mechanism is used to place a liquid container. The sampling needle 1 sucks the solution from the liquid container. The lifting motor 2 controls the up and down movement of the sampling needle 1 through the lead screw 6, and the rotating motor 3 controls the horizontal movement of the sampling needle 1 through the swing arm 7;

[0038] The quantitative loop liquid extraction module includes a first switching valve A, a second switching valve B and several quantitative loops. Several outlets of the first switching valve A are respectively connected to clean air sources and several quantitative loops, and the inlet is connected to the sampling needle 1; several outlets of the second switching valve B are respectively connected to the first discharge outlet C and several quantitative loops, and the inlet is connected in parallel to the liquid pump P and the clean air source; the inlet of the cleaning pool 4 is connected to the cleaning liquid pipeline N, and the outlet is connected to the second discharge outlet D; the inlet of the drying pool 5 is connected to the clean air source, and the outlet is connected to the third discharge outlet E. Through the switching of the switching valve and the conversion work of the sampling needle 1 among the liquid container, the cleaning pool 4 and the drying pool 5, quantitative loop sampling, cleaning of each passage, liquid discharge and drying are realized.

[0039] Optionally, the device for precise quantitative pipetting and liquid dispensing includes a main chassis, which is divided into two areas by a middle main frame for arranging a liquid processing module and a quantitative loop liquid sampling module respectively;

[0040] The middle main frame includes a base frame 8, two vertical track rods 9 and a moving cross bar 10. The lifting motor 2 is arranged on the base frame 8, and the base frame 8 is fixedly arranged on the bottom plate of the main chassis. The two ends of the base frame 8 are respectively provided with track rods 9, and the track rods 9 are perpendicular to the base frame 8; the moving cross bar 10 is horizontally arranged, and the two ends of the moving cross bar 10 are respectively slidably connected to the track rods 9. The rotating motor 3 is arranged on the moving cross bar 10.

[0041] One side of the base frame 8 facing the centering mechanism is the front side, and the other side is the back side. The lifting motor 2 is connected to the back side of the base frame 8. The cleaning pool 4 and the drying pool 5 are arranged on the bottom plate of the main chassis.

[0042] Further optionally, the top rotating shaft of the lifting motor 2 is connected to the bottom end of a lead screw 6, and the top end of the lead screw 6 is rotatably connected to the top plate of the main chassis. The lead screw passes through the moving cross bar 10. When the lifting motor 2 drives the lead screw 6 to rotate forward or backward, the moving cross bar 10 moves up or down along the spiral thread of the lead screw 6, thereby driving the rotating motor 3, the swing arm 7 and the sampling needle 1 to move up and down.

[0043] Optionally, a vertical hollow rotating shaft 12 is provided at the center of the rotating motor 3. The hollow vertical shaft passes through the rotating motor 3. The bottom of the hollow rotating shaft 12 is connected to a synchronous pulley 13, and the synchronous pulley 13 rotates synchronously with the hollow rotating shaft 12; the top of the hollow rotating shaft 12 is connected to one end of the swing arm 7, and the other end is suspended and connected to the top of the sampling needle 1. The swing arm 7 is horizontally arranged, and the swing arm 7 drives the sampling needle 1 to make a circular motion with the hollow rotating shaft 12 as the center and the length of the swing arm 7 as the radius.

[0044] Further optionally, the sampling needle 1 is a slender hollow tube capable of transmitting liquid; the top end of the sampling needle 1 is connected to an infusion tube 14. The infusion tube 14 extends along the swing arm 7 to the hollow rotating shaft 12, then extends along the hollow rotating shaft 12 and the synchronous pulley 13, and finally passes through the synchronous pulley 13 and is connected to the inlet of the first switching valve A to input the sampled liquid into the first switching valve A.

[0045] Optionally, the centering mechanism includes several vertical jaws 15, a support plate 16, a cam plate 17, several slideways 18, and a base plate 19 from top to bottom. The cam plate 17 and the support plate 16 are both provided with several hollow slots corresponding to the jaws, so that the jaws can pass through the cam plate 17 and the support plate 16; the slideways 18 are arranged on the base plate 19, and the jaws correspond to the slideways 18 one by one. The bottom of the jaw is slidably connected to the slideway 18 through a slider. Any one of the sliders is connected to a cylinder 20. The cylinder 20 can drive the jaw to move back and forth along the corresponding slideway 18. The movement of the jaw can drive the cam plate 17 to rotate, and the cam plate 17 can further drive other jaws to move back and forth along their respective corresponding slideways 18, so that all the jaws can approach or move away from the liquid container at the center of the support plate 16, realizing the action of clamping or loosening the liquid container.

[0046] Further optionally, both the base plate 19 and the support plate 16 are square, the cam plate 17 is circular, the top of the cam shaft 21 is fixedly connected to the center of the cam plate 17, the cam shaft 21 passes through the base plate 19 downward, the bottom of the cam shaft 21 is rotatably connected to the bottom plate below the base plate 19, and corresponding bearings are arranged outside the cam shaft 21, so that the cam plate 17 can rotate.

[0047] Further optionally, the upper surface of the base plate 19 is provided with several downwardly concave slideways 18. One end of the slideway 18 points to the center of the base plate 19, and the other end extends to the outer edge of the base plate 19. The several slideways 18 are evenly distributed around the base plate 19 in a radial pattern;

[0048] The support plate 16 is provided with several first hollow slots 22. One end of the first hollow slot 22 points to the center of the support plate 16, and the other end points to the outside of the support plate 16. The several first hollow slots 22 are evenly distributed around the support plate 16 in a radial pattern, and the first hollow slots 22 correspond to the positions of the slideways 18 one by one.

[0049] Further optionally, the cam plate 17 is evenly provided with several second hollow slots 23. The starting end of the second hollow slot 23 points to the center of the cam plate 17, and the ending end points to the outside of the cam plate 17; the radius of the cam plate 17 where the starting end of the second hollow slot 23 is located is the corresponding radius, and the included angle between the second hollow slot 23 and its corresponding radius is the rotation angle. The rotation angles of each second hollow slot 23 are the same, so that the several second hollow slots 23 are arranged in a spiral rotation form.

[0050] Further optionally, the first hollow slots 22 correspond to the second hollow slots 23 one by one. When the cam plate 17 rotates, the relative positions of the first hollow slots 22 and the second hollow slots 23 change, but the first hollow slots 22 and the second hollow slots 23 always intersect at the jaws.

[0051] Further optionally, the upper middle part of the jaw is above the pallet 16. A jaw bearing is provided at the part of the jaw corresponding to the cam plate 17, so that the jaw moves along the slideway 18 and the first hollow slot 22. When the cam plate 17 is driven to rotate through the second hollow slot 23, the relative position between the jaw and the cam plate 17 can rotate.

[0052] The pallet 16, the cam plate 17 and the base plate 19 are concentrically arranged. The first hollow slot 22 of the pallet 16 is arranged along the radial direction of the cam plate 17, that is, there is a rotation angle between the second hollow slot 23 and the first hollow slot 22. The second hollow slot 23 and the first hollow slot 22 always intersect at a point, and the jaw is always at this intersection point.

[0053] During use, all the jaws are away from the center of the pallet 16, and a liquid container (such as a volumetric flask) is placed at the center of the pallet 16. The driving rod of the air cylinder 20 is connected to the slider corresponding to one jaw, and the slider is pushed towards the center of the base plate 19. The jaw corresponding to the slider moves towards the center of the pallet 16 along the corresponding slideway 18 and the first hollow slot 22. The jaw penetrates through the second hollow slot 23, and the jaw also moves along the second hollow slot 23. However, the second hollow slot 23 and the first hollow slot 22 are not parallel. When the jaw moves along the second hollow slot 23 and the first hollow slot 22 simultaneously, since the four top corners of the pallet 16 are fixed on the base plate 19, the position of the first hollow slot 22 cannot move, and only the second hollow slot 23 can move. While the jaw moves along the second hollow slot 23, it drives the second hollow slot 23 to move, thereby pushing the cam plate 17 to rotate counterclockwise. The movement of other second hollow slots 23 drives the corresponding jaws to move towards the center of the pallet 16 along the first hollow slot 22, so as to uniformly clamp the liquid container, realizing the movement of all the jaws driven by one air cylinder 20. When loosening the liquid container, the air cylinder 20 drives one jaw to move towards the outside of the pallet 16, and the above actions are reversed.

[0054] The degree of the rotation angle can determine the rotation amplitude of the cam plate 17, which can be set according to actual needs. For example, the rotation angle is 5 - 20°.

[0055] The base plate 19 and the bottom plate of the main chassis can be connected by screws. The pallet 16 is connected to the base plate 19 and the bottom plate by screws. The slideway 18 is connected to the base plate 19 by screws.

[0056] Both the first switching valve A and the second switching valve B are conventional switching valves, specifically in the form of one inlet in parallel with several outlets. Here, the inlet and the outlet are used to distinguish the two ends of the switching valve. The inlet allows liquid or gas to enter and exit, and the outlet also allows liquid or gas to enter and exit.

[0057] Optionally, the inlet of the first switching valve A is connected to the top end of the sampling needle 1 through the infusion tube 14, and can output the taken liquid from the first switching valve A. The first switching valve A, the infusion tube 14 and the sampling needle 1 form a front-end passage;

[0058] One outlet of the first switching valve A is connected to a clean air source, and can input clean air into the front-end passage to blow out the residual liquid in the front-end passage into the cleaning pool 4;

[0059] The other outlets of the first switching valve A are respectively connected to one end of a quantitative loop. The other end of the quantitative loop is connected to the outlet of the second switching valve B. By switching the outlets of the two switching valves and using different quantitative loops, the cumulative error caused by using a single quantitative loop is avoided, and the pipetting accuracy is reduced.

[0060] Further optionally, the inlet of the second switching valve B is connected to the first opening of the three-way valve V. The second opening of the three-way valve V is connected to the liquid pump P. The third opening of the three-way valve V is connected to the clean air source; One outlet of the second switching valve B is connected to the first discharge port C. The passage between the three-way valve V, the second switching valve B and the first discharge port C forms a rear-end passage. The clean air source can input clean air into the rear-end passage to blow out the residual liquid in the rear-end passage from the first discharge port C; The liquid pump P serves as a power source and can suck the liquid sample or the cleaning liquid into the front-end passage, the pipelines of each quantitative loop and the rear-end passage through the sampling needle 1;

[0061] After the sampling needle 1 takes liquid for a certain quantitative loop, the sampling needle 1 is moved to the liquid container or the sample tube of another centering mechanism, and the clean air source can push out the sample liquid in the quantitative loop to achieve quantitative pipetting.

[0062] The liquid discharge of the front-end passage and the rear-end passage can be carried out simultaneously without mutual influence.

[0063] The precise quantitative pipetting and liquid dispensing device of the present invention can accurately sample the sample liquid in a liquid container, and then input the accurately measured volume of the sample liquid into a volumetric flask as a solute, waiting for subsequent preparation of a solution with a certain concentration. At this time, two centering mechanisms are provided for placing the liquid container and the volumetric flask respectively. Specifically, in the initial state, there is no liquid in all pipelines, and the inner and outer walls of the pipelines are dry.

[0064] Liquid sampling: Under the cooperation of the rotation motor 3 and the lifting motor 2, the sampling needle 1 extends into the liquid container. The inlet A1 and the outlet A2 of the first switching valve are communicated. The inlet B1 and the outlet B2 of the second switching valve are communicated. A quantitative loop G1 is connected between A2 and B2; B1 is connected to the liquid pump through a three-way valve. The liquid pump extracts the sample liquid, so that the liquid enters the quantitative loop G1 through the front-end passage (sampling needle 1, infusion tube 14, A1, A2), and also makes the quantitative loop G1, B2, B1 to the three-way valve filled with the sample liquid.

[0065] Front-end passage liquid drainage: The sampling needle 1 moves and extends into the cleaning pool 4. The inlet A1 of the first switching valve is communicated with the outlet A7. The clean air source F2 uses compressed air to drain the sample liquid in A1, the infusion tube 14 and the sampling needle 1 into the cleaning pool 4, and then discharges it through the second discharge outlet D, so that there is no sample liquid residue in the front-end passage.

[0066] Back-end passage liquid drainage: The inlet B1 of the second switching valve is communicated with the outlet B7. The outlet B7 is communicated with the first discharge outlet C. The three-way valve V is switched to connect to the clean air source F1. The clean air discharges the sample liquid in the back-end passage from the first discharge outlet C, so that there is no sample liquid residue in the back-end passage.

[0067] Quantitative pipetting: The sampling needle 1 moves and extends into the volumetric flask. Then, the A1 and A2 of the first switching valve are communicated, and the B1 and B2 of the second switching valve are communicated. The clean air source F1 uses clean air to push the sample liquid in the metering ring G1 into the volumetric flask as the solute. Then, solvent is added to the volumetric flask to prepare a solution with a specific concentration. The volumetric flask in this step can also be replaced with a sample tube to achieve pipetting of a specific volume of sample liquid.

[0068] Cleaning: After quantitative pipetting is completed, the sampling needle 1 extends into the cleaning pool 4 again. The cleaning liquid pipeline NN inputs cleaning liquid into the cleaning pool 4. The three-way valve V is switched to connect to the liquid pump P. The liquid pump P pumps the cleaning liquid through the front-end passage, the just-used G1, and the back-end passage into the liquid pump P, and then pushes the cleaning liquid back to the cleaning pool 4 along the original path, and pumps and cleans repeatedly for multiple times to realize the cleaning of the used pipeline. At the same time, since the sampling needle 1 is immersed in the cleaning pool 4, the outer wall of the sampling needle 1 is also cleaned. Finally, the waste liquid in the cleaning pool 4 is discharged through the second discharge outlet D.

[0069] Drying: The inner wall of the pipeline after cleaning is wet. The sampling needle 1 is moved to the drying pool 5. The three-way valve V is switched to connect to the clean air source F1. The clean compressed air blows the inner walls of the back-end passage, the just-used G1, and the front-end passage clean. At the same time, the clean air source F3 connected to the inlet of the drying pool 5 also inputs clean compressed air to dry the outer wall of the sampling needle 1. The waste gas and waste liquid in the drying pool 5 are discharged through the third discharge outlet E.

[0070] The clean air sources connected to the three-way valve, the cleaning pool 4, and the drying pool 5 can be the same one or three separate ones. The two switching valves can also use any one of the other metering rings G2, G3, G4, G5 connected to other outlets for quantitative pipetting. According to actual needs, by increasing or decreasing the number of channels of the two switching valves, more or fewer specifications of metering rings can be designed.

[0071] The present invention can achieve quantitative pipetting of multiple specifications and various liquids, greatly improving the pipetting efficiency and repeated pipetting accuracy. After each pipetting is completed, the pipeline and the pump chamber will be cleaned to avoid cross-contamination of various liquids. It can blow-dry the inner and outer walls of the pipetting pipeline and the sampling needle 1 to ensure that there is no moisture inside and outside the pipetting pipeline and the sampling needle 1 before each pipetting, reducing the impact on the sample liquid.

[0072] In the present invention, the operations of adding solvent, volume fixing, and mixing the solution in the volumetric flask are generally manual operations. Especially for volume fixing, it is very easy to introduce human errors and the accuracy is not high. The present invention provides the following solutions to solve this problem.

[0073] Optionally, a volume-fixing mechanism is further provided inside the main chassis. The volume-fixing mechanism includes a first infrared sensor, a second infrared sensor, a first turntable 24, two first support rods 26, and a liquid addition funnel 28. The two infrared sensors are arranged one above the other on the base frame 8 and are respectively used to indicate the upper limit of large-flow liquid inlet and the fine volume-fixing limit; the first support rod 26 is horizontally arranged, the first turntable 24 is vertically arranged, one end of the first support rod 26 is connected to the first turntable 24, and the other end clamps the liquid addition tube; the two first support rods 26 are respectively located at opposite positions of the first turntable 24.

[0074] Further optionally, the first infrared sensor includes a first infrared emitter 30 and a first infrared receiver, the second infrared sensor includes a second infrared emitter 31 and a second infrared receiver. The first infrared receiver and the second infrared receiver are detachably installed on the vertical inner wall of the main chassis opposite to the front of the base frame 8. A detachable vertical track portion 29 is provided on the front of the base frame 8 for slidably connecting the first infrared emitter 30 and the second infrared emitter 31.

[0075] In the traditional volume-fixing operation, after the solute is added to the volumetric flask, the solvent is first input in a large flow. When the liquid level is almost at the volume-fixing line, the flow rate is changed to a small flow or even dropped until the lowest point of the liquid level is flush with the volume-fixing line, and then the volumetric flask is sealed and repeatedly inverted and upright until the solution is mixed evenly.

[0076] The present invention simulates the above manual operation and makes mechanized improvements. Align the vertical track portion 29 with the vertical center line of the volumetric flask to be volumetrically fixed (at this time, the volumetric flask is clamped on the orientation mechanism and its position is fixed). The first infrared emitter 30 and the second infrared emitter 31 slide up and down on the vertical track portion 29 so that the first infrared emitter 30 is aligned with the middle of the volumetric line of the volumetric flask, and the second infrared emitter 31 is located below the first infrared emitter 30, for example, 2 - 5 cm away from the first infrared emitter, which serves as the upper limit for the input of high-flow solvent. The first infrared receiver is installed corresponding to the first infrared emitter 30 and can receive the infrared rays emitted by the first infrared emitter 30. The second infrared receiver is installed corresponding to the second infrared emitter 31 and can receive the infrared rays emitted by the second infrared emitter 31. According to the different volume specifications (such as 10 ml, 25 ml, 50 ml, etc.) of the volumetric flask, adjust the position of the vertical track portion 29 and the positions of the first infrared sensor and the second infrared sensor on the vertical track portion 29.

[0077] Further optionally, a horizontal secondary moving cross bar 11 is provided between the base frame 8 and the moving cross bar 10. The two ends of the secondary moving cross bar 11 are respectively detachably and slidably connected to the track rods 9. The motor of the first turntable 24 is slidably connected to the secondary moving cross bar 11, so that the first turntable 24 can move up and down and left and right;

[0078] On the side of the first turntable 24 facing the centering mechanism, there is a first support rod 26. The center of the side away from the centering mechanism is connected to the rotating shaft of the corresponding motor, and the motor drives the first turntable 24 to rotate.

[0079] Further optionally, centered on the center of the first turntable 24, the two first support rods 26 are symmetrically arranged. The distance between the two first support rods 26 is not greater than the diameter of the first turntable 24 and not less than the radius of the first turntable 24;

[0080] One end of a first support rod 26 away from the first turntable 24 clamps the high-flow liquid adding tube, and one end of the other first support rod 26 away from the first turntable 24 clamps the low-flow liquid adding tube;

[0081] Both the high-flow liquid adding tube and the low-flow liquid adding tube are connected to a container filled with solvent outside the main chassis. A liquid dropping pump is connected in the middle of the low-flow liquid adding tube for transporting and dropping the solvent drop by drop into the target volumetric flask. The liquid dropping pump is a conventional laboratory micro liquid dropping pump or a similar device. A general liquid pump is connected in the middle of the high-flow liquid adding tube.

[0082] Further optionally, the liquid adding funnel 28 is vertically arranged. The liquid adding funnel 28 is slidably connected to the secondary moving cross bar 11 through a connecting rod, or the liquid adding funnel 28 is connected to the motor of the first turntable 24 through a connecting rod, and the liquid adding funnel 28 can move its position in cooperation with the first turntable 24; both the large-flow liquid adding pipe and the small-flow liquid adding pipe pass through the liquid adding funnel 28 and then extend into the volumetric flask. The liquid adding funnel 28 cooperates to position the large- and small-flow liquid adding pipes, making it easy for the two liquid adding pipes to enter the volumetric flask during lifting and lowering.

[0083] As a specific implementation manner, the liquid adding funnel 28 is connected to the motor of the first turntable 24 through a connecting rod. The connecting rod is L-shaped. The vertical part of the connecting rod is connected to the motor, and the horizontal part is connected to the liquid adding funnel 28. The height of the liquid adding funnel 28 is lower than that of the first turntable 24; the first support rods 26 can be inclined, that is, the clamping ends of the two first support rods 26 are close to each other.

[0084] After the two infrared sensors locate the volumetric flask, move the secondary moving cross bar 11 to an appropriate height, move the first turntable 24 along the secondary moving cross bar 11 to an appropriate position, and lower the secondary moving cross bar 11 so that the bottom of the liquid adding funnel 28 abuts against the mouth of the target volumetric flask (at this time, the solute has been quantitatively transferred to the volumetric flask). Both the large-flow liquid adding pipe and the small-flow liquid adding pipe pass through the liquid adding funnel 28 and then extend into the volumetric flask. When the first turntable 24 rotates, the large- and small-flow liquid adding pipes move up and down in the opposite direction. Starting from the clamping end of the first support rod 26, the small-flow liquid adding pipe is shorter than the large-flow liquid adding pipe, which is convenient for the small-flow liquid adding pipe to perform volume fixing at the upper part of the volumetric flask.

[0085] First, rotate the first turntable 24 so that the large-flow liquid adding pipe descends close to the bottom of the volumetric flask, and the small-flow liquid adding pipe ascends to the upper part of the volumetric flask, or even above the liquid adding funnel 28, or detaches from the liquid adding funnel 28. While the large-flow liquid adding pipe is inputting the solvent, it gradually rises through the rotation of the first turntable 24, so that the bottom end of the large-flow liquid adding pipe is always above the liquid surface and not far from the liquid surface, avoiding liquid splashing. When the bottom end of the large-flow liquid adding pipe passes through the sensing height of the second infrared sensor, the second infrared sensor senses once as a preparatory signal; when the liquid surface passes through the sensing height of the second infrared sensor, the second infrared sensor senses again as a signal for the end of large-flow liquid addition, and the large-flow liquid adding pipe stops infusing. The first turntable 24 continues to rotate in the same direction, and the large-flow liquid adding pipe continues to rise until it detaches from the liquid adding funnel 28. During this process, the small-flow liquid adding pipe may enter the liquid adding funnel 28 and keep descending below the liquid surface, but it has no impact on volume fixing.

[0086] The first turntable 24 rotates in the reverse direction, and the small-flow liquid adding pipe rises until its bottom end is higher than the liquid level at this time but lower than the fixed volume line. At this time, the large-flow liquid adding pipe descends, and it can be placed into the cleaning tank 4 or the drying tank 5. The small-flow liquid adding pipe drops the solvent and gradually rises driven by the first turntable 24. When the bottom end of the small-flow liquid adding pipe passes through the sensing height of the first infrared sensor, the first infrared sensor senses once, serving as a preliminary fixed volume signal; when the liquid level passes through the sensing height of the first infrared sensor, the first infrared sensor senses once again, serving as a signal for the end of small-flow liquid addition, that is, the fixed volume is completed, and the small-flow liquid adding pipe stops dripping. The first turntable 24 continues to rotate in the reverse direction, and the small-flow liquid adding pipe rises into the liquid adding funnel 28. The fixed volume mechanism is convenient to operate, simple in structure, low in cost, reusable, and uses an infrared sensor for multiple inductions, with high fixed volume accuracy.

[0087] Optionally, a mixer is further provided in the main chassis. The mixer includes a second turntable 25 and two second support rods 27. The second support rods 27 are horizontally arranged and parallel to each other. The second turntable 25 is vertically arranged, and the motor of the second turntable 25 is detachably installed on the inner wall of the main chassis opposite to the middle main frame; one end of the second support rod 27 is connected to the second turntable 25, and the other end extends towards the middle main frame and is provided with a clamping portion 34 for clamping the thin neck of the volumetric flask.

[0088] Further optionally, the center of the second turntable 25 is connected to the rotating shaft of the corresponding motor, and the motor drives the second turntable 25 to rotate; the two second support rods 27 are on a vertical line passing through the center of the second turntable 25. A first slide rail 32 is provided on this vertical line, and the two second support rods 27 are detachably slidably connected to the first slide rail 32, and the distance between the two second support rods 27 can be adjusted according to the thin neck height of volumetric flasks of different specifications;

[0089] A second slide rail 33 is provided on the inner wall of the main chassis, and the motor of the second turntable 25 is slidably connected to the second slide rail 33, and the height of the second support rod 27 can be adjusted according to the height of volumetric flasks of different specifications.

[0090] For volumetric flasks of different specifications, second support rods 27 of different lengths can be selected to be adapted to the volumetric flasks. The target volumetric flask is first stably positioned, and the second turntable 25 is above the volumetric flask. According to the specification size of the target volumetric flask, the distance between the two second support rods 27 is adjusted. The clamping portion 34 is a conventional openable and closable gripper, which can be electromagnetically controlled. The clamping portion 34 is opened, and the second turntable 25 descends, driving the clamping portions 34 of the two second support rods 27 to descend, so that the thin neck part of the volumetric flask penetrates into the two clamping portions 34, and the clamping portion 34 closes to clamp the volumetric flask. The centering mechanism releases the volumetric flask, and the second turntable 25 drives the volumetric flask to rise until the bottom of the volumetric flask is higher than the top of the clamping jaws. The second turntable 25 rotates, and the second support rod 27 drives the volumetric flask to perform a circular motion on the vertical plane to fully mix the internal liquid.

[0091] After mixing, the second turntable 25 returns the volumetric flask to the centering mechanism, then releases the volumetric flask, and the second turntable 25 moves upward so that the two clamping portions 34 are disengaged from the volumetric flask.

Claims

1. A device for precise quantitative pipetting and liquid preparation, characterized in that, It includes a liquid handling module and a quantitative loop liquid sampling module. The liquid handling module includes a sampling needle, a lifting motor, a rotating motor, a cleaning pool, a drying pool, and at least one centering mechanism. The centering mechanism is used to place a liquid container. The sampling needle sucks the solution from the liquid container. The lifting motor controls the up and down movement of the sampling needle through a lead screw. The rotating motor controls the horizontal movement of the sampling needle through a swing arm. The quantitative loop liquid sampling module includes a first switching valve, a second switching valve, and several quantitative loops. The several outlets of the first switching valve are respectively connected to a clean air source and several quantitative loops, and the inlet is connected to the sampling needle. The several outlets of the second switching valve are respectively connected to a first discharge port and several quantitative loops, and the inlet is connected in parallel to a liquid pump and a clean air source. The inlet of the cleaning pool is connected to a cleaning liquid pipeline. The inlet of the drying pool is connected to a clean air source. The centering mechanism includes several jaws, a support plate, a cam plate, several slideways, and a base plate from top to bottom. The cam plate and the support plate are both provided with hollow grooves corresponding to the jaws, so that the jaws can pass through the cam plate and the support plate. The slideways are arranged on the base plate, and the jaws correspond to the slideways one by one. The bottom of the jaw is slidably connected to the slideway through a slider. Any one slider is connected to a cylinder, and the cylinder can drive the jaw to move back and forth along the corresponding slideway. The movement of the jaw can drive the cam plate to rotate, and the cam plate then drives other jaws to move back and forth along their respective corresponding slideways, so that all jaws can approach or move away from the liquid container at the center of the support plate, realizing the action of clamping or loosening the liquid container. One end of the slideway points to the center of the base plate, and the other end extends to the outer edge of the base plate. The several slideways are evenly distributed around the base plate in a radial pattern. The support plate is provided with several first hollow grooves. One end of the first hollow groove points to the center of the support plate, and the other end points to the outside of the support plate. The several first hollow grooves are evenly distributed around the support plate in a radial pattern, and the positions of the first hollow grooves correspond to those of the slideways one by one.

2. The device for precise quantitative pipetting and liquid dispensing according to claim 1, wherein The device for precise quantitative liquid transfer and liquid dispensing includes a main chassis, and the main chassis is divided into two regions by a middle main frame. The middle main frame includes a base frame, a moving crossbar, and two vertical track rods. The lifting motor is arranged on the base frame. The two ends of the base frame are respectively provided with track rods, and the track rods are perpendicular to the base frame. The two ends of the moving crossbar are respectively slidably connected to the track rods, and the rotating motor is arranged on the moving crossbar.

3. The device for precise quantitative pipetting and liquid dispensing according to claim 2, characterized in that, The top rotating shaft of the lifting motor is connected to the bottom end of the lead screw. The lead screw passes through the moving crossbar. When the lifting motor drives the lead screw to rotate forward or backward, the moving crossbar rises or falls along the spiral texture of the lead screw, thereby driving the rotating motor, the swing arm, and the sampling needle to move up and down.

4. The device for precise quantitative pipetting and liquid dispensing according to claim 2, characterized in that, The center of the rotating motor is provided with a vertical hollow rotating shaft. The bottom of the hollow rotating shaft is connected to a synchronous pulley, and the synchronous pulley rotates synchronously with the hollow rotating shaft. The top of the hollow rotating shaft is connected to one end of the swing arm, and the other end of the swing arm is suspended and connected to the top of the sampling needle. The sampling needle is a slender hollow tube. The top end of the sampling needle is connected to an infusion tube. The infusion tube extends along the swing arm to the hollow rotating shaft, then extends along the hollow rotating shaft and the synchronous pulley, and finally passes through the synchronous pulley and is connected to the inlet of the first switching valve.

5. The device for precise quantitative pipetting and liquid dispensing according to claim 1, characterized in that, The center of the cam plate is fixedly connected to the top of the cam rotating shaft. The cam rotating shaft passes through the base plate downward, and the bottom of the cam rotating shaft is rotatably connected to a bottom plate below the base plate. The cam plate is evenly provided with a number of second hollow slots. The starting end of each second hollow slot points to the center of the cam plate, and the ending end points to the outside of the cam plate. The radius of the cam plate where the starting end of the second hollow slot is located is the corresponding radius. The angle between the second hollow slot and the corresponding radius is the rotation angle, and the rotation angles of each second hollow slot are the same, so that a number of second hollow slots are arranged in a spiral rotation form.

6. The device for precise quantitative pipetting and liquid dispensing according to claim 1, characterized in that, The first switching valve, the infusion tube and the sampling needle form a front-end passage. One outlet of the first switching valve is connected to a clean air source, which can input clean air into the front-end passage to blow out the residual liquid in the front-end passage into the cleaning pool. The other outlets of the first switching valve are respectively connected to one end of a quantitative loop, and the other end of the quantitative loop is connected to the outlet of the second switching valve. By switching the outlets of the two switching valves, different quantitative loops are used.

7. The device for precise quantitative pipetting and liquid dispensing according to claim 1, characterized in that, The inlet of the second switching valve is connected to opening one of the three-way valve. Opening two of the three-way valve is connected to the liquid pump, and opening three of the three-way valve is connected to the clean air source. The passage between the three-way valve, the second switching valve and up to the first row of outlets forms a back-end passage. The clean air source can input clean air into the back-end passage to blow out the residual liquid in the back-end passage from the first row of outlets. The liquid pump serves as a power source and can suck the liquid sample or cleaning liquid into the front-end passage, the pipelines of each quantitative loop and the back-end passage through the sampling needle. After the sampling needle takes liquid for a certain quantitative loop, the sampling needle is then moved to the liquid container or sample tube of another centering mechanism. The clean air source can push out the sample liquid in the quantitative loop to achieve quantitative liquid transfer.

8. The device for precise quantitative pipetting and liquid dispensing according to claim 2, wherein, A constant volume mechanism is also provided in the main chassis. The constant volume mechanism includes a first infrared sensor, a second infrared sensor, a first turntable, two first support rods and a liquid adding funnel. The two infrared sensors are arranged one above the other on the base frame and are respectively used to indicate the upper limit of large-flow liquid inlet and the fine constant volume limit. The first support rods are horizontally arranged, the first turntable is vertically arranged, one end of the first support rod is connected to the first turntable, and the other end clamps the liquid adding tube. The two first support rods are respectively located at opposite positions of the first turntable.

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