CN106799266A - A kind of hand-held capacity calibration device of pipettor and calibration method - Google Patents

Abstract

The invention discloses a hand-held pipette capacity calibration device and a pipette calibration method, through which the upper computer controls the rotation of the servo motor, the mutual movement of the ball screw and the slider, etc., to realize the mechanical device to take the liquid of the pipette, Transfer and discharge operations, through image processing technology to realize the calculation of the height of the liquid level in the liquid container to determine the lifting height of the pipette when taking liquid, through the electronic balance, temperature sensor to realize the collection of pipetting data, and according to the verification regulations "JJG 646-2006" writes programs on the host computer to realize data processing. The main feature of the present invention is that through the operation of the mechanical device and the host computer program, the manual weighing method is improved to calibrate the pipette, which realizes the automation in the single-point calibration of the pipette, and reduces the single-point repeated operation and large data. The error caused by the amount of processing can be analyzed and the calibration report can be given at the same time.

Description

A kind of hand-held pipette volume calibration device and calibration method

technical field

The present invention relates to the field of pipettes, in particular to a volume calibration device and calibration method for a hand-held pipette. The method and device mainly involve calibrating the relative error and volume repeatability of the pipette gun (under specified conditions, Use a reference standard to assign values to the characteristics of measuring instruments, including reference materials, and determine their indication errors).

Background technique

Pipettes are widely used in hospitals, health and epidemic prevention stations, blood transfusion stations, biochemical laboratories, environmental laboratories, and food analysis laboratories. They are precision liquid sampling instruments that can quickly and accurately quantify a small amount of liquid samples and test solutions. Sampling and sample addition, for adjustable pipettes, the operator can also adjust the capacity value of the pipette according to actual needs. As a necessary equipment for pipetting, the calibration of its capacity directly affects the measurement results. However, in the long-term use process, operation, temperature, human factors, etc. will affect its accuracy. Insufficient or excessive pipetting may cause production accidents or deviations in research results. In order to ensure that the result data has good precision, accuracy and reliability, it must be calibrated regularly.

The traditional pipette calibration method adopts the measurement method, that is, weigh the quality of the pure water released by the pipette under test within a certain scale, and then obtain the actual volume of the pipette under test based on the density of the water, and then Compare with checkpoint capacity. Since each capacity verification point needs to be detected 6 times according to the national regulations, 18 liquid extraction and discharge operations are required to detect the 3 capacity values of an adjustable pipette. Therefore, the operation steps of this method are repeated, complicated, and Manual operation will bring some errors.

In terms of hardware, the high-degree-of-freedom simulation manipulators produced by some foreign companies can realize the operation of pipettes to a certain extent. However, in the actual use of calibrating pipettes, too many degrees of freedom are not required. Degrees of freedom are wasteful, and the high cost hinders their use in pipette calibration. In terms of software, the pipette calibration system designed in China is also constantly improving, which can efficiently process and analyze a large amount of collected data. However, only the automation of data processing has been realized, and there is still a gap in the automation of pipette control. .

Contents of the invention

The purpose of the present invention is to provide a hand-held pipette volume calibration device and a calibration method to solve the defects of the calibration method in the background technology.

The purpose of the present invention is achieved through the following technical solutions: a hand-held pipette volume calibration device, which is composed of the following components: upper computer, experimental console, first servo motor, first coupling, first ball wire rod, two first bearings, first ball nut, first nut seat, first bracket, second servo motor, second coupling, second ball screw, second bearing, second ball nut, second Nut seat, second bracket, fourth servo motor, guide rod, calibrated pipette, CCD camera, round float, beaker, electronic balance, conical beaker, temperature sensor. The first servo motor, the second servo motor, the fourth servo motor, and the temperature sensor are respectively connected to the host computer through the IO module, and the electronic balance and the CCD camera are respectively connected to the host computer;

The first servo motor, the two first bearings, the beaker, and the electronic balance are sequentially fixed on the experimental console; the beaker is filled with measuring liquid, and the circular float floats on the measuring liquid; the conical beaker is placed on the electronic balance Above; the temperature sensor is installed in the conical beaker to measure the temperature of the liquid in the conical beaker in real time.

Both ends of the first ball screw are installed on the experimental console through the first bearing, the output shaft of the first servo motor is connected with the first ball screw through the first coupling, and the first ball nut is sleeved on the first ball screw. On the lead screw; the first servo motor drives the first ball screw to rotate, so that the first ball nut moves horizontally; the first nut seat is installed on the top of the first ball nut, and moves horizontally synchronously with the first ball nut; the first bracket vertically Fixed on the first nut seat, perpendicular to the first ball screw, the second servo motor is fixed on the bottom of the first bracket, the two ends of the second ball screw are installed on the first bracket through the second bearing, the second servo motor The output shaft of the motor is connected with the second ball screw through the second coupling, the second ball nut is sleeved on the second ball screw, and the second servo motor drives the second ball screw to rotate, so that the second ball nut Move in the vertical direction; the second nut seat is connected with the second ball nut and moves synchronously with the second ball nut; one end of the second bracket is horizontally fixed on the second nut seat, and the fourth servo motor and the pipette are clamped The device is fixed on the other end of the second bracket, the output shaft of the fourth servo motor is connected with the guide rod, and the guide rod is driven to rotate by the fourth servo motor to realize the pressing of the pipette gun clamped by the pipette clamping device. The CCD camera is fixed at the lower end of the pipette holder.

A pipette calibration method based on a hand-held pipette volume calibration device, comprising the following steps:

(1) The movement of the first servo motor is controlled by the host computer, and the CCD camera collects images in real time. When the pipette gun clamped by the pipette clamping device is above the beaker, the first servo motor is turned off;

(2) Control the movement of the fourth servo motor through the host computer, drive the guide rod to press the top of the pipette gun, and turn off the fourth servo motor after the pressing action is completed;

(3) Then control the movement of the second servo motor through the upper computer, so that the second ball nut moves down the distance D1, and the tip of the pipette held by the pipette clamping device is inserted 2 to 3 mm below the liquid surface; then close second servo motor;

(4) Reversely control the fourth servo motor until the guide rod resets, turn off the fourth servo motor, the pressing effect of the guide rod on the top of the pipette gun disappears, and the pipette gun draws a full-scale measurement liquid from the beaker;

(5) Control the movement of the second servo motor through the host computer, so that the second ball nut moves upwards by the same distance D1, and then turn off the second servo motor;

(6) The upper computer obtains the initial weight through the electronic balance. At the same time, it controls the movement of the first servo motor, and the CCD camera collects images in real time. When the pipette gun clamped by the pipette clamping device is above the conical beaker, close the first servo motor;

(7) The movement of the second servo motor is controlled by the host computer, so that the second ball nut moves downward for a distance D2, and the tip of the pipette held by the pipette holding device is inserted into the lower part of the conical beaker but does not touch the liquid surface; Then turn off the second servo motor;

(8) Control the movement of the fourth servo motor through the host computer, drive the guide rod to press the top of the pipette gun, and transfer the full-scale measurement liquid into the conical beaker; then reversely control the fourth servo motor until the guide rod resets and closes For the fourth servo motor, the pressing effect of the guide rod on the top of the pipette disappears; and the movement of the second servo motor is controlled by the host computer, so that the second ball nut moves upward by the same distance D2, and then the second servo motor is turned off.

(9) The upper computer obtains the end point weight through the electronic balance, and obtains the temperature of the liquid in the conical beaker through the temperature sensor.

(10) The upper computer obtains the corresponding calibration coefficient correlation coefficient K(t) at the liquid temperature through the actual temperature t of the temperature sensor, and further obtains the actual weight m according to the end point weight and the initial weight, and obtains the actual volume V'=K(t) m.

(11) Perform n times of measurements according to steps 1 to 10, and obtain the volume data measured under the range V ₁ , which is V ₁₁ '～V _1n ';

(12) Adjust the range of the pipette gun, and perform n measurements (n=6.) according to steps 1 to 10, and obtain the volume data V _i1 '～V _in ' under the range V _i ;

(13) According to the measured volume and the actual volume, the relative error and volume repeatability of the pipette are obtained. Among them, the relative error of the capacity under the range V _i is:

in,

The capacity repeatability is: in

The beneficial effect of the present invention is that: the present invention realizes the automation of volume calibration for a single hand-held pipette, and greatly reduces repeated operations of calibration workers.

Description of drawings

Fig. 1 is the structural representation of calibration device of the present invention;

In the figure, the experimental console 1, the first servo motor 2, the first coupling 3, the first ball screw 4, the first bearing 5, the first ball nut 6, the first nut seat 7, the first bracket 8, Second servo motor 9, second coupling 10, second ball screw 11, second bearing 12, second ball nut 13, second nut seat 14, second bracket 15, fourth servo motor 16, guide rod 17. Calibrated pipette 18, CCD camera 20, circular float 21, beaker 22, electronic balance 23, conical beaker 24, temperature sensor 33.

detailed description

As shown in Figure 1, a hand-held pipette volume calibration device is composed of the following components: upper computer, experimental console 1, first servo motor 2, first coupling 3, first ball screw 4, Two first bearings 5, first ball nut 6, first nut seat 7, first bracket 8, second servo motor 9, second coupling 10, second ball screw 11, two second bearings 12 , second ball nut 13, second nut seat 14, second bracket 15, fourth servo motor 16, guide rod 17, calibrated pipette 18, CCD camera 20, circular float 21, beaker 22, electronic balance 23 , Conical beaker 24, temperature sensor 33. The first servo motor 2, the second servo motor 9, the fourth servo motor 16, and the temperature sensor 33 are respectively connected to the host computer through an IO module, and the electronic balance 23 and the CCD camera 20 are respectively connected to the host computer;

The first servo motor 2, the first coupling 3, the first ball screw 4, the two first bearings 5, the first ball nut 6, and the first nut holder 7 form a horizontal transport system. The first bracket 8, the second The servo motor 9, the second shaft coupling 10, the second ball screw 11, the second bearing 12, the second ball nut 13, and the second nut seat 14 constitute a vertical transportation system, and the two systems work together to achieve the measured displacement The position of the liquid gun is tightly adjusted.

The first servo motor 2, two first bearings 5, a beaker 22, and an electronic balance 23 are sequentially fixed on the experimental console 1; the beaker 22 contains a measuring liquid, and the circular float 21 floats on the measuring liquid; The conical beaker 24 is placed on the electronic balance 23; the temperature sensor 33 is installed in the conical beaker 24 to measure the temperature of the liquid in the conical beaker 24 in real time.

The two ends of the first ball screw 4 are installed on the experimental console 1 through the first bearing 5, the output shaft of the first servo motor 2 is connected with the first ball screw 4 through the first coupling 3, the first ball The nut 6 is set on the first ball screw 4; the first servo motor 2 drives the first ball screw 4 to rotate, so that the first ball nut 6 moves horizontally; the first nut seat 7 is installed on the top of the first ball nut 6, and The first ball nut 6 moves horizontally synchronously; the first bracket 8 is vertically fixed on the first nut seat 7, perpendicular to the first ball screw 4, the second servo motor 9 is fixed on the bottom of the first bracket 8, and the second ball The two ends of the lead screw 11 are installed on the first bracket 8 through the second bearing 12, the output shaft of the second servo motor 9 is connected with the second ball screw 11 through the second coupling 10, and the second ball nut 13 sets On the second ball screw 11, the second servo motor 9 drives the second ball screw 11 to rotate, so that the second ball nut 13 moves in the vertical direction; the second nut seat 14 is connected with the second ball nut 13, Move synchronously with the second ball nut 13; one end of the second bracket 15 is horizontally fixed on the second nut seat 14, the fourth servo motor 16 and the pipette clamping device 18 are fixed on the other end of the second bracket 15, the fourth The output shaft of the servo motor 16 is connected with the guide rod 17, and the guide rod 17 is driven to rotate by the fourth servo motor 16, so as to press the pipette gun clamped by the pipette clamping device 18. The CCD camera 20 is fixed on the lower end of the pipette holding device 18 .

The pipette calibration method based on the above-mentioned hand-held pipette volume calibration device, comprising the following steps:

(1) Control the movement of the first servo motor 2 by the host computer, and the CCD camera 20 collects images in real time, and when the pipette gun clamped by the pipette clamping device 18 is above the beaker, close the first servo motor 2;

(2) Control the movement of the fourth servo motor 16 through the host computer, drive the guide rod 17 to press the top of the pipette gun, and turn off the fourth servo motor 16 after the pressing action is completed;

(3) Then the host computer controls the movement of the second servo motor 9, so that the second ball nut 13 moves downward by a distance D1, and the tip of the pipette held by the pipette clamping device 18 is inserted 2 to 3 mm below the liquid surface ; Then close the second servo motor 9;

(4) Reversely control the fourth servo motor 16 through the upper computer until the guide rod 17 is reset, turn off the fourth servo motor 16, the pressing effect of the guide rod 17 on the top of the pipette disappears, and the pipette draws the full volume from the beaker the measuring liquid;

(5) Control the movement of the second servo motor 9 through the host computer, so that the second ball nut 13 moves upwards by the same distance D1, and then close the second servo motor 9;

(6) The upper computer obtains the initial weight through the electronic balance 23, and at the same time, controls the movement of the first servo motor 2, and the CCD camera 20 collects images in real time. , turn off the first servo motor 2;

(7) The movement of the second servo motor 9 is controlled by the host computer, so that the second ball nut 13 moves down the distance D2, and the pipette tip held by the pipette clamping device 18 is inserted into the lower part of the conical beaker 24 but not Contact liquid surface; Then close the second servo motor 9;

(8) Control the movement of the fourth servo motor 16 through the host computer, drive the guide rod 17 to press the top of the pipette gun, and transfer the full-scale measuring liquid to the conical beaker 24; then reversely control the fourth servo motor 16 through the host computer , until the guide rod 17 is reset, the fourth servo motor 16 is turned off, and the pressing effect of the guide rod 17 on the top of the pipette disappears; and the movement of the second servo motor 9 is controlled by the host computer, so that the second ball nut 13 moves upward by the same distance D2 , and then turn off the second servo motor 9.

(9) The upper computer obtains the end point weight through the electronic balance 23, and obtains the temperature of the liquid in the conical beaker 24 through the temperature sensor 33.

(10) The upper computer obtains the corresponding calibration coefficient correlation coefficient K(t) under the liquid temperature through the actual temperature t of the temperature sensor 33, and further obtains the actual weight m according to the end point weight and the initial weight, and obtains the actual volume V'=K(t ) m.

(11) Perform n times of measurements according to steps 1 to 10, and obtain the volume data measured under the range V ₁ , which is V ₁₁ '～V _1n ';

(12) Adjust the range of the pipette gun, perform 6 measurements according to steps 1 to 10, and obtain the volume data V _i1 '～V _in ' under the range V _i ;

(13) According to the measured volume and the actual volume, the relative error and volume repeatability of the pipette are obtained. Among them, the relative error of the capacity under the range V _i is:

in,

The capacity repeatability is: in

Claims (3)

1. A hand-held pipette volume calibration device, consisting of the following components: upper computer, experimental console (1), first servo motor (2), first coupling (3), first ball screw (4), two first bearings (5), the first ball nut (6), the first nut seat (7), the first bracket (8), the second servo motor (9), the second coupling ( 10), the second ball screw (11), the second bearing (12), the second ball nut (13), the second nut seat (14), the second bracket (15), the fourth servo motor (16), Guide rod (17), calibrated pipette (18), CCD camera (20), circular float (21), beaker (22), electronic balance (23), conical beaker (24), temperature sensor (33 )Wait. Described first servomotor (2), the second servomotor (9), the 4th servomotor (16), temperature sensor (33) are connected with upper computer by IO module respectively; Electronic balance (23), CCD camera ( 20) respectively connected with the host computer; The first servo motor (2), two first bearings (5), beaker (22), electronic balance (23) are fixed on the experiment console (1) successively; Fill measuring liquid in the described beaker (22), The circular float (21) floats on the measuring liquid; the conical beaker (24) is placed on the electronic balance (23); the temperature sensor (33) is installed in the conical beaker (24), and the real-time measurement of the conical beaker ( 24) Internal liquid temperature. The two ends of the first ball screw (4) are installed on the experimental console (1) through the first bearing (5), and the output shaft of the first servo motor (2) is connected with the first shaft coupling (3) through the first coupling (3). The ball screw (4) is connected, and the first ball nut (6) is sleeved on the first ball screw (4); the first servo motor (2) drives the first ball screw (4) to rotate, so that the first ball The nut (6) moves horizontally; the first nut seat (7) is installed on the top of the first ball nut (6), and moves horizontally synchronously with the first ball nut (6); the first bracket (8) is vertically fixed on the first nut On the seat (7), perpendicular to the first ball screw (4), the second servo motor (9) is fixed on the bottom of the first bracket (8), and the two ends of the second ball screw (11) pass through the second bearing (12) Installed on the first bracket (8), the output shaft of the second servo motor (9) is connected with the second ball screw (11) through the second coupling (10), and the second ball nut (13 ) is set on the second ball screw (11), the second servo motor (9) drives the second ball screw (11) to rotate, so that the second ball nut (13) moves in the vertical direction; the second nut seat (14) is connected with the second ball nut (13), and moves synchronously with the second ball nut (13); one end of the second support (15) is horizontally fixed on the second nut seat (14), and the fourth servo motor ( 16) and the pipette holding device (18) are fixed on the other end of the second support (15), and the output shaft of the fourth servo motor (16) is connected with the guide rod (17), and the fourth servo motor (16) ) drives the guide rod (17) to rotate to realize the pressing of the pipette gun clamped by the pipette clamping device (18). The CCD camera (20) is fixed on the lower end of the pipette holding device (18). 2. A pipette calibration method based on the hand-held pipette volume calibration device claimed in claim 1, characterized in that the method comprises the following steps: (1) Control the movement of the first servo motor (2) through the host computer, and the CCD camera (20) collects images in real time. When the pipette gun clamped by the pipette clamping device (18) is located above the beaker, the first servo motor is turned off. Motor (2); (2) Control the movement of the fourth servo motor (16) through the host computer, drive the guide rod (17) to press the top of the pipette gun, and turn off the fourth servo motor (16) after the pressing action is completed; (3) The movement of the second servo motor (9) is controlled by the host computer, so that the second ball nut (13) moves down a distance D1, and the tip of the pipette held by the pipette holding device (18) is inserted into the liquid. 2～3mm below the surface; then close the second servo motor (9); (4) The fourth servo motor (16) is reversely controlled by the upper computer until the guide rod (17) is reset, the fourth servo motor (16) is turned off, the pressing effect of the guide rod (17) on the top of the pipette gun disappears, and the transfer The liquid gun draws the full range of measuring liquid from the beaker; (5) Control the movement of the second servo motor (9) through the host computer, so that the second ball nut (13) moves upwards by the same distance D1, and then close the second servo motor (9); (6) The upper computer obtains the initial weight through the electronic balance (23), and at the same time, controls the movement of the first servo motor (2), and the CCD camera (20) collects images in real time. When the liquid gun is above the conical beaker (24), close the first servo motor (2); (7) The movement of the second servo motor (9) is controlled by the host computer, so that the second ball nut (13) moves down a distance D2, and the pipette tip held by the pipette holding device (18) is inserted into the cone. shaped beaker (24) bottom but do not touch the liquid surface; then close the second servo motor (9); (8) Control the movement of the fourth servo motor (16) through the host computer, drive the guide rod (17) to press the top of the pipette gun, and transfer the full-scale measuring liquid to the conical beaker (24); Control the fourth servo motor (16) until the guide rod (17) resets, turn off the fourth servo motor (16), and the pressing effect of the guide rod (17) on the top of the pipette disappears; and control the second servo motor through the host computer (9) moves so that the second ball nut (13) moves up the same distance D2, and then turns off the second servo motor (9). (9) The upper computer obtains the end point weight through the electronic balance (23), and obtains the liquid temperature in the conical beaker (24) through the temperature sensor (33). (10) The upper computer obtains the corresponding calibration coefficient correlation coefficient K (t) under the liquid temperature through the actual temperature t of the temperature sensor (33), further obtains the actual weight m according to the end weight and the initial weight, and obtains the actual volume V'=K (t) m. (11) Perform n times of measurements according to steps 1 to 10, and obtain the volume data measured under the range V ₁ , which is V ₁₁ '～V _1n '; (12) Adjust the range of the pipette gun, perform n measurements according to steps 1 to 10, and obtain the volume data V _i1 '～V _in ' under the range V _i ; (13) According to the measured volume and the actual volume, the relative error and volume repeatability of the pipette are obtained. Among them, the relative error of the capacity under the range V _i is: in, The capacity repeatability is: in 3. The method according to claim 2, characterized in that n=6.