A method for a pneumatic pipette to identify pipette tips

Abstract

The present invention discloses a method for a pneumatic pipette to identify pipette tips. First, a reference value is set. Then, the pipette tip to be detected is sleeved and inserted on the mounting mouth. The processing module controls the driving device to operate at a set speed, and pushes or / and pulls the piston from one end to the other end in the inner cavity of the piston tube. During this process, the pressure detection module detects the air pressure value in the air pressure chamber, and compares the detected air pressure value with the set reference values of pipette tips of various volume specifications or models stored in the storage chip. When the processing module determines that the detected value falls within the threshold range of the set reference value of the corresponding volume specification or model pre-stored in the storage chip, the processing module determines that the installed pipette tip is the volume specification or model corresponding to the set reference value threshold range, and outputs the determination result of the pipette tip volume specification or model. In the process of identifying the specification and model of the pipette tip, the operation method of the present invention is simple, the identification sensitivity is high, and it is accurate and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, specifically to a pneumatic pipetting technology for medical detection devices, and particularly to a method for a pneumatic pipette to identify pipette tips. Background Art

[0002] Many experiments in the biomedical industry often require detecting and processing a large number of samples. For example, in a hospital's laboratory department, a large number of blood samples or urine samples need to be detected and processed every day. To more efficiently detect samples, it is generally necessary to use detection equipment. During the detection process, reagents usually need to be added to complete the detection of relevant samples. And the dosage of the added reagent may affect the final detection result. Currently, most laboratories use pipettes to drip chemical reagents. When using a pipette for dripping work, the staff needs to select the corresponding pipette tip (abbreviation: TIP tip or tip), and install the selected specification of pipette tip on the liquid suction and discharge assembly of the pipette to ensure the accuracy of the dripping volume. Due to the requirements of different application scenarios and occasions, the same model of liquid suction and discharge assembly needs to be adapted to pipette tips of different volumes. The commonly used pipette tips on the current market generally have volume specifications such as 0.1, 0.3, 0.5, 1 ml, 2 ml, etc. Each time the liquid is sucked and discharged, a new pipette tip needs to be replaced. The same model of liquid suction and discharge assembly can be adapted to the same interface and pipette tips of different volumes.

[0003] The pipettes in the prior art do not have the function of identifying pipette tips of different volumes. If the volume specification of the replaced pipette tip is incorrect during the process of replacing the pipette tip, it will affect the detection result and even cause waste of samples. Summary of the Invention

[0004] In view of the above deficiencies in the prior art, the present invention provides a method for a pneumatic pipette to identify pipette tips. First, a reference value is set. Then, the pipette tip to be detected is sleeved and inserted on the mounting mouth. The processing module controls the driving device to operate at a set speed, and pushes or / and pulls the piston from one end to the other end in the inner cavity of the piston tube. During this process, the pressure detection module detects the air pressure value in the air pressure chamber, and compares the detected air pressure value with the set reference values of pipette tips of various volume specifications or models stored in the storage chip. When the processing module determines that the detected value falls within the threshold range of the set reference value of the corresponding volume specification or model pre-stored in the storage chip, the processing module determines that the installed pipette tip is the volume specification or model corresponding to the set reference value threshold range, and outputs the determination result of the pipette tip volume specification or model. In the process of identifying the specification and model of the pipette tip of the present invention, the operation method is simple, the identification cost is low, and the identification sensitivity is high, and the identification is accurate and reliable.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0006] A method for a pneumatic pipette to identify pipette tips, the pneumatic pipette comprising: a housing, a driving device and a push-pull assembly mounted on the housing, a transmission assembly, a pressure detection module, a processing module and a storage chip are further provided in the housing, the push-pull assembly comprising a piston tube, a piston inserted in the piston tube, and a piston rod connected to the piston, the inner cavity of the piston tube below the lower end face of the piston forms a cylinder, and a mounting nozzle is further sleeved at the lower end of the piston tube. The method for identifying pipette tips comprises the following steps:

[0007] Step S100: Set a reference value. Insert a calibrated pipette tip onto the mounting nozzle. The cylinder communicates with the inner cavity of the pipette tip to jointly form a pneumatic chamber. The processing module controls the driving device to operate at a set speed, and through the transmission assembly, the piston is pushed or / and pulled from one end to the other end in the inner cavity of the piston tube. During the pushing and pulling process, the pressure value in the pneumatic chamber is detected by the pressure detection module and written into the storage chip. After the pressure value of a pipette tip of one volume specification is written, replace it with another calibrated pipette tip of a different volume specification to obtain the threshold range of the set reference values of various volume specifications of pipette tips and record them in the storage chip;

[0008] Step S200: Insert the pipette tip to be detected onto the mounting nozzle;

[0009] Step S300: The processing module controls the driving device to operate at a set speed, and the piston is pushed or / and pulled from one end to the other end in the inner cavity of the piston tube. During the pushing and pulling process, the pressure value in the pneumatic chamber is detected by the pressure detection module, and the detected pressure value is compared with the set reference value of the pipette tip of the corresponding volume specification or model stored in the storage chip;

[0010] Step S400: When the processing module determines that the detected value falls within the threshold range of the set reference value of the corresponding volume specification or model pre-stored in the storage chip, the processing module determines that the installed pipette tip is the volume specification or model corresponding to the threshold range of the set reference value, and outputs the determination result of the pipette tip volume specification or model.

[0011] In step S400, the determination result of the pipette tip volume specification or model is output, and the output method can be to display it on a display screen electrically connected to the pneumatic pipette, or to send it to the mobile handheld terminal of the staff.

[0012] Further, when it is necessary to determine whether the volume specification or model of the pipette tip is correctly installed, between step S200 and step S300, step S210 is added,

[0013] Step S210: Input the volume specification or model information of the pipette tip to be detected, and inform the processing module of the volume specification or model information of the installed pipette tip.

[0014] After step S400, add step S500.

[0015] Step S500: When the detected value is consistent with the set reference value corresponding to the volume specification or model in step S210 stored in the storage chip, the processing module determines that the pipette tip is correctly selected and issues a signal indicating correct result or does not issue a signal; when the detected value is inconsistent with the set reference value corresponding to the volume specification or model in step S210 stored in the storage chip, the processing module determines that the pipette tip is incorrectly selected and issues a warning signal indicating incorrect result.

[0016] Further, in step S100 and step S300, the set speed is: the processing module controls the driving device to rotate at a set speed of 20±2 r / s, or the rotation speed of the driving device is controlled such that the air volume change in the air pressure chamber is 17.35±2 μl / r.

[0017] In step S100 and step S300, the air pressure value includes: the air pressure peak value and / or the air pressure valley value. The processing module controls the piston to push at least once from one end to the other end and / or pull from the other end to one end in the inner cavity of the piston tube to obtain at least one air pressure peak value and / or one air pressure valley value.

[0018] Furthermore, in step S100 and step S300, the air pressure value further includes the waveform curve of the air pressure change between the peak value and the valley value.

[0019] In step S100, the processing module processes the received air pressure value. The processing method is that the processing module floats all the received air pressure peak values, air pressure valley values, and waveform curves upward by 10% and downward by 10% respectively to form the threshold range of each set reference value.

[0020] In step S300, the processing module compares the detected values of the air pressure peak value, air pressure valley value, and waveform curve received with the threshold range of each set reference value to determine whether each detected value is within the threshold range of the corresponding set reference value.

[0021] As another preferred solution, in step S100, the processing module screens the received air pressure values, and respectively screens out the maximum value and the minimum value of the air pressure peak value, and the maximum value and the minimum value of the air pressure valley value.

[0022] Float the maximum value of the air pressure peak by 10%, float the minimum value of the air pressure peak by 10%, and the value range between the air pressure peak with the minimum value floating by 10% and the air pressure peak with the maximum value floating by 10% constitutes the threshold range of the set reference value of the air pressure peak;

[0023] Float the maximum value of the air pressure valley by 10%, float the minimum value of the air pressure valley by 10%, and the value range between the air pressure valley with the minimum value floating by 10% and the air pressure valley with the maximum value floating by 10% constitutes the threshold range of the set reference value of the air pressure valley.

[0024] Further, in step S300, the processing module screens the received air pressure values, screens out each air pressure peak, takes its average value as the detected air pressure peak, and compares it with the threshold range of the set reference value of the air pressure peak to determine whether it falls within the threshold range of the set reference value; screens out each air pressure valley, takes its average value as the detected air pressure valley, and compares it with the threshold range of the set reference value of the air pressure valley to determine whether it falls within the threshold range of the set reference value.

[0025] Furthermore, when the detected air pressure peak and / or air pressure valley falls within the threshold range of the corresponding set reference value, the processing module determines that the comparison is consistent and the pipette tip is correctly installed; when the detected air pressure peak or / and air pressure valley is not within the threshold range of the corresponding set reference value, the processing module determines that the comparison is inconsistent, the pipette tip is incorrectly installed, the processing module controls the driving device to pause, and controls the warning module to issue a warning message.

[0026] Preferably, the warning module is installed on the housing and electrically connected to the processing module. The warning module includes a warning light or / and a buzzer, and the warning message is to turn on a red light or / and emit a warning sound.

[0027] For the above method for a pneumatic pipette to identify a pipette tip, the pneumatic pipette is installed on a rack, the transmission component is arranged on one side inside the housing, one end of the push-pull component penetrates the housing and is connected to the transmission component, the driving device is a motor, the driving device is fixed to the upper end of the housing by screws, and a printed circuit board is also arranged inside the housing. The pressure detection module, the processing module, and the storage chip are all installed on the printed circuit board, or the storage chip and the processing module are integrally arranged, and the printed circuit board is electrically connected to the driving device through a wire;

[0028] The output shaft of the driving device penetrates the housing and is connected to the end of the transmission component away from the push-pull component. When the driving device rotates, it transmits kinetic energy to the push-pull component through the transmission component, driving the piston rod and piston of the push-pull component to move up and down in the piston tube.

[0029] Further, a detection port is provided on the pressure detection module. The detection port is communicated with the air pressure chamber through a conduit for detecting the air pressure value inside the air pressure chamber;

[0030] The transmission assembly includes a lead screw and a nut. One side of the nut is sleeved on the lead screw and is in screw connection with the lead screw. The other side of the nut is connected to the push-pull assembly. The lower end of the lead screw is arranged inside the housing and is rotatably connected to the housing. The upper end of the lead screw is connected to the output shaft of the driving device;

[0031] The transmission assembly further includes a first support frame and a second support frame. The push-pull assembly is connected to the first support frame. The second support frame is arranged below the first support frame. The first support frame is fixedly connected to the nut and the two are relatively stationary. When the first support frame moves up and down, the push-pull assembly moves up and down following the first support frame.

[0032] Furthermore, a channel is opened in the mounting nozzle. One end of the channel is communicated with the inner cavity of the piston tube, and the other end of the channel is connected to the inner cavity of the pipette tip;

[0033] An "L"-shaped channel is also opened in the mounting nozzle. One end of the "L"-shaped channel communicates with the channel, and the other end of the "L"-shaped channel is connected to the conduit;

[0034] A push head is also sleeved on the mounting nozzle. The push head is slidably connected to the mounting nozzle, and the lower end surface of the push head can push against the upper end surface of the pipette tip. A push rod is connected to the push head. The end of the push rod away from the push head penetrates through the housing and is connected to the second support frame. The push head can move along the height direction of the mounting nozzle.

[0035] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

[0036] A method for a pneumatic pipette to identify pipette tips proposed by the present invention first sets a reference value, then inserts the pipette tip to be detected onto the mounting nozzle, and sends the volume specification or model information of the pipette tip to be detected to the processing module; then the processing module controls the driving device to rotate quickly, and senses the air resistance by means of rapid inhalation and rapid exhalation. The pressure detection module will detect the air pressure value in the air pressure chamber in real time and transmit it to the processing module. The processing module screens out the air pressure peak value and the air pressure valley value in the air pressure value, and respectively compares them with the threshold range of the air pressure peak value setting reference value and the threshold range of the air pressure valley value setting reference value to determine whether it is within the threshold range of the setting reference value. Furthermore, it determines whether the model of the pipette tip installed on the pipette is correct, and can identify the volume specification or model of the installed pipette tip. When used to determine whether the pipette tip is installed correctly, when the processing module determines that the detected value is consistent with the setting reference value of the corresponding volume specification or model stored in the storage chip, the processing module determines that the pipette tip is correctly selected and emits a signal indicating correct result or does not emit a signal; when the detected value is inconsistent with the setting reference value of the corresponding volume specification or model stored in the storage chip, the processing module determines that the pipette tip is incorrectly selected, the processing module controls the driving device to suspend operation, and controls the warning module to emit a warning message of turning on a red light or / and emitting a warning sound to remind the staff that the pipette tip is incorrectly selected and ask them to confirm or replace it.

[0037] The method for a pneumatic pipette to identify pipette tips proposed by the present invention is simple to operate, low in identification cost, high in identification sensitivity, and accurate and reliable in the process of identifying the pipette tip specification model. It solves the defects of the existing pipettes that cannot identify the pipette tip specification model and cannot judge whether the pipette tip is incorrectly selected. Brief Description of the Drawings

[0038] The present invention will be described by way of examples with reference to the drawings, where:

[0039] Figure 1 It is a schematic diagram of the suction and discharge liquid assembly of the pneumatic pipette without a pipette tip installed;

[0040] Figure 2 It is a schematic diagram of the suction and discharge liquid assembly of the pneumatic pipette after a pipette tip is installed;

[0041] Figure 3 It is a schematic diagram of the structure of the pipette tip;

[0042] Figure 4 It is a schematic diagram of the suction and discharge liquid assembly of the pneumatic pipette replacing with different volume pipette tips;

[0043] Figure 5 It is a schematic diagram of the structure of the pneumatic pipette capable of identifying pipette tips provided by the present invention

[0044] Figure 6 Stereoscopic structure diagram of a pneumatic pipette capable of recognizing pipette tips provided by the present invention;

[0045] Figure 7 Schematic structural diagram of the transmission component provided by the present invention;

[0046] Figure 8 Schematic structural diagram of the push-pull component provided by the present invention;

[0047] Figure 9 is Figure 1 Enlarged structural diagram at position I in

[0048] Figure 10 is Figure 3 Enlarged structural diagram at position II in

[0049] Figure 11 Top view structural diagram of a pneumatic pipette capable of recognizing pipette tips provided by the present invention;

[0050] Figure 12 Waveform diagram when the pneumatic pipette recognizes a pipette tip with a specification of 300 μl without a filter;

[0051] Figure 13 Waveform diagram when the pneumatic pipette recognizes a pipette tip with a specification of 1000 μl without a filter.

[0052] Icon: 110 - housing; 210 - processing module; 250 - card slot; 111 - groove; 115 - printed circuit board; 130 - driving device; 150 - transmission component; 151 - lead screw; 153 - nut; 155 - first support frame; 157 - second support frame; 170 - push-pull component; 171 - piston rod; 173 - piston tube; 175 - piston; 177 - mounting nozzle; 179 - channel; 181 - pipette tip; 183 - push head; 185 - push rod; 187 - blocking block; 189 - spring; 190 - pressure detection module; 191 - detection port; 195 - conduit; 197 - trigger piece; 199 - sensor; 230 - warning module. Detailed implementation manners

[0053] The following combines Figures 1 to 12 to describe the present invention in detail.

[0054] A pneumatic pipette includes one or more liquid suction and discharge components, Figure 1 , Figure 2 and Figure 4 The schematic diagram of the liquid suction and discharge component of the pneumatic pipette is shown in Figure 6 and Figure 11The figure shows a schematic structural diagram of a pneumatic pipette that only includes one liquid suction and discharge component. When the pneumatic pipette includes multiple liquid suction and discharge components, the structures of the multiple liquid suction and discharge components are the same and they are snap-fitted side by side. When the pneumatic pipette only includes one liquid suction and discharge component, the pneumatic pipette and the liquid suction and discharge component can be equivalent.

[0055] The method for identifying pipette tips proposed by the present invention is mainly applicable to pneumatic pipettes. The pneumatic pipette includes: a housing 110, a driving device 130 mounted on the housing 110, a push-pull component 170, and a warning module 230. The warning module 230 includes one or both of a warning light and a buzzer. The driving device 130 is a motor, and the driving device 130 is fixed to the upper end of the housing 110 by screws. A transmission component 150, a pressure detection module 190, a processing module 210, and a storage chip are further provided in the housing 110. A printed circuit board 115 is arranged in the housing 110. The warning module 230, the pressure detection module 190, the processing module 210, and the storage chip are all mounted on the printed circuit board 115, and the warning module 230, the pressure detection module 190, and the storage chip are all electrically connected to the processing module 210. The printed circuit board 115 is electrically connected to the driving device 130 through a wire; the storage chip and the processing module 210 can be separately and independently arranged, or they can be integrally arranged, that is, the storage chip is embedded in the processing module 210.

[0056] Please refer to Figure 8 , the push-pull component 170 includes a piston tube 173, a piston 175 inserted into the piston tube 173, and a piston rod 171 connected to the piston 175. The piston tube 173 is tubular and has a cylindrical inner cavity along the axis. The piston 175 is arranged in the piston tube 173, and the piston 175 can move up and down along the axis direction in the piston tube 173. The inner cavity of the piston tube 173 below the lower end face of the piston 175 forms a cylinder, and a mounting nozzle 177 is further sleeved at the lower end of the piston tube 173. The upper end of the mounting nozzle 177 is fixedly connected to the lower end of the piston tube 173, and the connection between the mounting nozzle 177 and the piston tube 173 can maintain airtightness to prevent the gas in the piston tube 173 from leaking out through this connection.

[0057] The method for identifying pipette tips applicable to pneumatic pipettes proposed in this embodiment includes the following steps:

[0058] Step S100: Set a reference value. Insert the calibrated pipette tip 181 onto the mounting nozzle 177. The air cylinder communicates with the inner cavity of the pipette tip 181 and together they form a pneumatic chamber. The processing module 210 controls the driving device 130 to operate at a set speed. Through the transmission assembly 150, the piston 175 is pushed and pulled from one end to the other end within the inner cavity of the piston tube 173. During the pushing and pulling process, the pressure detection module 190 detects the air pressure value in the pneumatic chamber and writes it into the storage chip. After the air pressure value of a pipette tip 181 of one volume specification is written, replace it with a pipette tip 181 of another calibrated volume specification to obtain the threshold range of the set reference value for various volume specifications of the pipette tip 181 and record it in the storage chip;

[0059] Step S200: Insert the pipette tip 181 to be detected onto the mounting nozzle 177;

[0060] Step S300: The processing module 210 controls the driving device 130 to operate at a set speed, and pushes and pulls the piston 175 from one end to the other end within the inner cavity of the piston tube 173. During the pushing and pulling process, the pressure detection module 190 detects the air pressure value in the pneumatic chamber, and compares the detected air pressure value with the set reference value of the pipette tip 181 of the corresponding volume specification or model stored in the storage chip;

[0061] Step S400: When the processing module 210 determines that the detected value falls within the threshold range of the set reference value of the corresponding volume specification or model stored in the storage chip, the processing module 210 determines that the installed pipette tip is of the volume specification or model corresponding to the threshold range of the set reference value, and outputs the determination result of the volume specification or model of the pipette tip 181.

[0062] In step S400, the determination result of the volume specification or model of the pipette tip is output, and the output method can be to display it on the display screen electrically connected to the pneumatic pipette, or send it to the mobile handheld terminal of the staff. In this embodiment, it is preferably output to the display screen.

[0063] As another embodiment, when it is necessary to determine whether the volume specification or model of the pipette tip 181 is installed correctly, between step S200 and step S300, add step S210,

[0064] Step S210: Input the volume specification or model information of the pipette tip 181 to be detected, that is, inform the processing module 210 of the volume specification or model information of the installed pipette tip 181;

[0065] After step S400, add step S500,

[0066] Step S500: When the detected value is consistent with the set reference value stored in the storage chip corresponding to the volume specification or model in step S210, the processing module 210 determines that the pipette tip 181 is correctly selected and issues a signal indicating correct result or does not issue a signal; when the detected value is inconsistent with the set reference value stored in the storage chip corresponding to the volume specification or model in step S210, the processing module 210 determines that the pipette tip 181 is incorrectly selected and issues a warning signal indicating incorrect result.

[0067] As Figure 3 shown, the pipette tip 181 is formed by connecting a cylindrical tube and a conical tube. The large end of the pipette tip 181 is a cylindrical tube and can be sleeved on the mounting nozzle 177. The small end of the pipette tip 181 is a pointed tip. The volume of the pipette tip is generally divided into specifications such as 0.1, 0.3, 0.5, 1 ml, 2 ml, etc. The diameters of the large ends of the pipette tips 181 with different volume specifications are the same and can all be tightly sleeved and installed on the mounting nozzle 177. The opening diameters of the small ends of the pipette tips 181 with different volume specifications are different. The larger the volume of the pipette tip 181, the larger the opening diameter of the pointed tip at its small end; correspondingly, the smaller the volume of the pipette tip 181, the smaller the opening diameter of the pointed tip at its small end.

[0068] After the pipette tip 181 is sleeved and installed on the mounting nozzle 177, when the pipette tips 181 with different volume specifications are inserted into the mounting nozzle 177, the volumes of their air pressure chambers are different, and the opening diameters of the pointed tips of the pipette tips 181 are also different.

[0069] In this embodiment, in steps S100 and S300, the set speed is: the processing module 210 controls the driving device 130 to rotate at a set speed of 20 ± 2 r / s, or the rotation speed of the driving device 130 is controlled so that the air volume change in the air pressure chamber is 17.35 ± 2 μl / r, and at this time, the air flow rate in the air pressure chamber ≤ 0.3 Mach.

[0070] In steps S100 and S300, the air pressure value includes: air pressure peak value and / or air pressure valley value. The processing module 210 controls the piston 175 to push from one end to the other end and / or pull from the other end to one end at least once in the inner cavity of the piston tube 173 to obtain at least one air pressure peak value and / or one air pressure valley value.

[0071] As another specific embodiment, in steps S100 and S300, the air pressure value further includes a waveform curve of the change of the air pressure between the peak value and the valley value;

[0072] In step S100, the processing module 210 processes the received air pressure values. The processing method is that the processing module 210 floats all the received air pressure peaks, air pressure valleys, and waveform curves upward by 10% and downward by 10% respectively to form the threshold ranges of each set reference value.

[0073] In step S300, the processing module 210 compares the detected values of the received air pressure peaks, air pressure valleys, and waveform curves with the threshold ranges of each set reference value to determine whether each detected value is within the threshold range of the corresponding set reference value.

[0074] As a specific implementation manner, in step S100, when setting the reference value, as a setting method of the reference value, the processing module 210 screens the received air pressure values, and respectively screens out the maximum and minimum values of the air pressure peaks and the maximum and minimum values of the air pressure valleys.

[0075] The maximum value of the air pressure peak is floated upward by 10%, the minimum value of the air pressure peak is floated downward by 10%, and the value range between the air pressure peak with the minimum value floated downward by 10% and the air pressure peak with the maximum value floated upward by 10% constitutes the threshold range of the set reference value of the air pressure peak.

[0076] The maximum value of the air pressure valley is floated upward by 10%, the minimum value of the air pressure valley is floated downward by 10%, and the value range between the air pressure valley with the minimum value floated downward by 10% and the air pressure valley with the maximum value floated upward by 10% constitutes the threshold range of the set reference value of the air pressure valley.

[0077] Further, in step S300, the processing module 210 screens the received air pressure values, screens out each air pressure peak, takes its average value as the detected air pressure peak, and compares it with the threshold range of the set reference value of the air pressure peak to determine whether it is within the threshold range of the set reference value; screens out each air pressure valley, takes its average value as the detected air pressure valley, and compares it with the threshold range of the set reference value of the air pressure valley to determine whether it is within the threshold range of the set reference value.

[0078] When the detected air pressure peak and / or air pressure valley falls within the threshold range of the corresponding set reference value, the processing module 210 determines that the comparison is consistent and the pipette tip 181 is correctly selected; when the detected air pressure peak or / and air pressure valley is not within the threshold range of the corresponding set reference value, the processing module 210 determines that the comparison is inconsistent, the pipette tip 181 is incorrectly selected, the processing module 210 controls the driving device 130 to suspend operation, and controls the warning module 230 to send out a warning message. The warning message can be to turn on a red light, or / and emit a warning sound through a buzzer.

[0079] In this embodiment, the pneumatic pipette is installed on the frame. The transmission assembly 150 is disposed on one side inside the housing 110. One end of the push-pull assembly 170 penetrates through the housing 110 and is connected to the transmission assembly 150. The output shaft of the driving device 130 penetrates through the housing 110 and is connected to the end of the transmission assembly 150 away from the push-pull assembly 170. When the driving device 130 rotates, kinetic energy is transmitted to the push-pull assembly 170 through the transmission assembly 150, driving the piston rod 171 and the piston 175 of the push-pull assembly 170 to move up and down within the piston tube 173.

[0080] In another embodiment, the driving device 130 can also be a power device with an ultra-precision positioning control system, such as a voice coil motor, which can more accurately control the distance that the piston 175 moves up and down within the piston tube 173.

[0081] A detection port 191 is provided on the pressure detection module 190. The detection port 191 is communicated with the air pressure chamber through a conduit 195 and is used to detect the air pressure value inside the air pressure chamber.

[0082] Please refer to Figure 6 , Figure 7 As shown, the transmission assembly 150 includes a lead screw 151 and a nut 153. One side of the nut 153 is sleeved on the lead screw 151 and is threadedly connected to the lead screw 151. The other side of the nut 153 is connected to the push-pull assembly 170. The lower end of the lead screw 151 is disposed inside the housing 110 and is rotatably connected to the housing 110. The upper end of the lead screw 151 is connected to the output shaft of the driving device 130.

[0083] The transmission assembly 150 further includes a first support frame 155 and a second support frame 157. The push-pull assembly 170 is connected to the first support frame 155. The second support frame 157 is disposed below the first support frame 155. The first support frame 155 is fixedly connected to the nut 153 and they are relatively stationary. A groove 111 is provided inside the housing 110. The first support frame 155 is installed in the groove 111 and can slide up and down within the groove 111. When the output shaft of the driving device 130 drives the lead screw 151 to rotate, the groove 111 restricts the first support frame 155 and the nut 153 from rotating with the lead screw 151, so that the first support frame 155 moves up and down along the length direction of the lead screw 151. The push-pull assembly 170 is detachably connected to the first support frame 155. When the first support frame 155 moves up and down, the push-pull assembly 170 moves up and down following the first support frame 155. The second support frame 157 is disposed below the first support frame 155. The second support frame 157 is in contact with the inner surface of the housing 110, which can make the push-pull assembly 170 more stable during the movement process.

[0084] In other real-time modes, the transmission component 150 can also be a crank-slider structure, a gear-rack structure, a cam structure, or other transmission structures that can convert the rotational motion of the driving device 130 into a linear motion.

[0085] The piston 175 is connected to the first support frame 155 through the piston rod 171. The upper end of the piston rod 171 penetrates through the second support frame 157 and then is connected to the first support frame 155. The piston rod 171 is slidably connected to the second support frame 157. The second support frame 157 guides the up-and-down movement of the piston rod 171. The piston rod 171 is detachably connected to the first support frame 155 and is relatively stationary.

[0086] Furthermore, a sealing ring can be provided on the circumference of the piston 175 to enhance the sealing effect between the piston 175 and the inner cavity of the piston tube 173. When the driving device 130 rotates, the first support frame 155 is driven to move upward or downward through the lead screw 151. The piston rod 171 moves synchronously with the first support frame 155, thereby driving the piston 175 to move within the piston tube 173, increasing or decreasing the cylinder space below the piston 175, and thus realizing the aspiration or ejection of the liquid sample.

[0087] Preferably, the push-pull component 170 can also adopt a plunger structure. Compared with the piston structure, the gap between the plunger and the piston tube of the plunger structure is smaller, and the length of the plunger is greater than the length of the piston. Therefore, the sealing performance of the plunger structure is better, and gas is not easily leaked from the connection between the plunger and the piston tube, making the pressure value detected by the pressure detection module 190 more accurate.

[0088] Furthermore, a channel 179 is opened in the mounting nozzle 177. One end of the channel 179 is communicated with the inner cavity of the piston tube 173, and the other end of the channel is connected to the inner cavity of the pipette tip 181;

[0089] The detection port 191 is communicated with the channel 179 through a conduit 195. An "L"-shaped channel is also opened in the mounting nozzle 177. One end of the "L"-shaped channel is communicated with the channel 179, and the other end of the "L"-shaped channel is communicated with the conduit 195.

[0090] It should be noted that in this embodiment, one end of the "L"-shaped channel communicates with channel 179, and the pressure detection module 190 detects the pressure value inside channel 179. In other embodiments, one end of the "L"-shaped channel can also communicate with the upper or lower end of channel 179. That is, when one end of the "L"-shaped channel communicates with the upper end of channel 179, the pressure value detected by the pressure detection module 190 is the pressure value inside the cylinder; when one end of the "L"-shaped channel communicates with the lower end of channel 179, the pressure value detected by the pressure detection module 190 is the pressure value inside the pipette tip 181. Although the connection position of the "L"-shaped channel is different, it has no impact on the specification recognition result of the pipette tip 181.

[0091] A push head 183 is also sleeved on the mounting nozzle 177. The push head 183 is slidably connected to the mounting nozzle 177, and the lower end surface of the push head 183 can abut against the upper end surface of the pipette tip 181. A push rod 185 is connected to the push head 183. One end of the push rod 185 away from the push head 183 penetrates through the housing 110 and is connected to the second support frame 157. The push head 183 can move along the height direction of the mounting nozzle 177. When detecting a liquid sample, the pipette tip 181 needs to be frequently replaced. When the pipette tip 181 needs to be replaced, after aligning the pipette tip 181 to be removed and replaced with the pipette tip receiving box, the driving device 130 rotates, the first support frame 155 moves downward and fits and pushes the second support frame 157 downward. Since the second support frame 157 is connected to the push head 183 through the push rod 185, the push head 183 will also move downward along the mounting nozzle 177 and contact and push the pipette tip 181 to separate it from the mounting nozzle 177, so as to complete the work of peeling off the pipette tip 181.

[0092] Furthermore, as Figures 6 to 10 shown, a blocking block 187 and a spring 189 are provided at one end of the push rod 185 close to the housing 110. The blocking block 187 is fixedly connected to the push rod 185, and the spring 189 is sleeved on the push rod 185 and is located between the blocking block 187 and the housing 110;

[0093] A sensor 199 is also provided on the printed circuit board 115, and the sensor 199 is electrically connected to the processing module 210. A trigger piece 197 for triggering the sensor 199 is provided on the second support frame 157. When the second support frame 157 moves upward in place along with the push rod 185, the trigger piece 197 connected to the second support frame 157 can touch the sensor 199, and the sensor 199 transmits the touch information to the processing module 210. The processing module 210 determines that the pipette tip 181 has been installed on the mounting nozzle 177 based on the information that the sensor 199 has been touched.

[0094] When replacing the pipette tip 181, if the tight-fitting relationship between the upper orifice of the pipette tip 181 and the mounting nozzle 177 becomes loose, it is possible for the pipette tip 181 to fall off midway. When this occurs, the spring 189 will push the push rod 185 downward due to its elastic force. In this embodiment, the elastic force of the spring 189 is less than the frictional force between the pipette tip 181 and the mounting nozzle 177. The push rod 185 drives the second support frame 157 downward, and the trigger piece 197 no longer abuts against and triggers the sensor 199. The non-contact of the sensor 199 indicates that the pipette tip 181 has fallen off. After the processing module 210 receives the "signal of pipette tip falling off", the pipettor will reinstall the pipette tip 181 again. Through the mutual cooperation between the sensor 199, the push head 183 and the push head 183, the function of automatically detecting whether the pipette tip 181 has fallen off is realized.

[0095] Please refer to Figure 12 and Figure 13 As shown, for the method for identifying a pipette tip applicable to a pneumatic pipettor proposed in this embodiment, the calculation process is exemplified as follows:

[0096] When the piston 175 moves downward from the top in the piston tube 173, the starting time point is set as t0 and the air pressure value is p0. The end time point when the piston 175 moves from the top to the bottom in the piston tube 173 is t1, and the corresponding air pressure value is p1. The time when the air pressure in the tip changes back to p0 from p1 is denoted as t2.

[0097] When the piston 175 moves downward in the piston tube 173 at a set linear velocity a, the gas in the air pressure chamber will be compressed and discharged outward through the tip opening. The gas pressure in the air pressure chamber changes from p0 to p1 from time t0 to t1, and a changing curve is obtained;

[0098] According to the Clapeyron equation:

[0099] pV = mRT…………………(1)

[0100] Taking the derivative of both sides of "=" gives: pdV + Vdp = mRdT + RTdm

[0101] Dividing both sides of "=" by mRT gives:

[0102]

[0103] Equation (2) is the differential equation for the change of the air pressure value in the air pressure chamber, where, represents the change rate of the gas pressure curve in the air pressure chamber;

[0104] Now analyze The moment, i.e., the moment when the air pressure value in the air pressure chamber reaches the extreme value / peak value.

[0105] The tip outlet diameter D of the pipette tip o Compared with the cylinder diameter or piston diameter D1, there is a huge difference in size. When the piston 175 starts to move downward to compress the air in the air pressure chamber, the air pressure p in the air pressure chamber increases, and the tip of the pipette tip starts to exhaust air. Since the diameter D of the tip outlet of the pipette tip o is much smaller than the cylinder diameter, the gas pressure in the air pressure chamber will increase, and its pressure change is a unidirectional increasing curve with time from t0 to t1, that is the moment of, which is the moment t1 [1] .

[0106] Now, two pipette tips with different specifications are used as examples to illustrate:

[0107] Such as Figure 4 shown, for example: two pipette tips 181 with volumes of 300ul and 1000ul respectively, the installation diameter of their cylindrical tube ends is set as D2. The installation diameters D2 of the two pipette tips are the same and can both be sleeved on the installation nozzle 177. The outlet diameters of the tip ends of the two pipette tips are respectively set as D o1 and D o2 , where the outlet diameter of the tip end of the 300ul pipette tip is set as D o1 , and the outlet diameter of the tip end of the 1000ul pipette tip is set as D o2 .

[0108] D o1 <D o2 , that is, the larger the volume of the pipette tip, the larger the outlet diameter D o of its tip end.

[0109] Characterizes the change rate of the gas pressure curve in space, the larger it is, the steeper the pressure p curve, the smaller it is, the flatter the pressure p curve;

[0110] It can be seen from conclusion [1] that the peak value of the pressure curve p in the space appears at the moment t1, that is, in the time period from t0 to t1, the larger it is, the larger the peak value of p [2] .

[0111] In this embodiment, different specifications of pipette tips are identified by comparing the differences in the peak air pressures in the air pressure chamber when different specifications of pipette tips 181 are installed on the pipette. Of course, it is also possible to compare other characteristics of the pressure curve, such as the slope of the pressure curve, by integrating the pressure curve for comparison, or by comparing characteristics such as the area or differential of the pressure curve. When transformed to use these technical characteristics for comparison to identify pipette tips, the method is also within the scope of protection of the present invention.

[0112] For equation (2), There are three parameters that affect:

[0113] For dV = a.dt, where a is the piston running speed, assumed to be a constant value, then dV is a constant value, V = V 气缸 + V 枪头 , the larger the volume of the tip, the larger V is, and vice versa; assume that when pipette tips of 300ul and 1000ul are installed on the pipette, the volumes of the air pressure chambers are V3 and V 10 , V3 < V 10 Then there is:

[0114]

[0115] The absolute value is taken here because the piston moves downward to compress the space and dV is negative;

[0116] For Assume that when pipette tips of 300ul and 1000ul are installed on the pipette, the air temperatures in the space are T3 and T 10 ,

[0117] Characterizes the air temperature change rate in the air pressure chamber;

[0118] Simplify the model. When the piston moves downward, at any time from t to t + dt, there is:

[0119] Assume that when pipette tips of 300ul and 1000ul are installed on the pipette, the volumes of the air pressure chambers are V3 and V 10 , V3 < V 10 ;

[0120] For the installation of a 300ul tip,

[0121]

[0122] For the installation of a 1000ul tip

[0123]

[0124] As can be seen from equation (3),

[0125]

[0126] For characterizing the change rate of the gas outflow at the tip of the gun, at any time from t to t + dt, there is

[0127]

[0128] where m t+dt and m t are respectively the amounts of air in the pressure chamber at t + dt and t;

[0129] From the expression on the right side of "=" in Equation (5), it can be seen that it characterizes the flow rate q of the air amount at the tip of the gun [3]

[0130] The air velocity at the tip of the gun is:

[0131]

[0132] Neglecting the frictional losses along the way, there is

[0133]

[0134] where h is the head difference between the pressure chamber and the environment, and this value can be regarded as a constant from t to t + dt;

[0135] S o = Πr 2 , which is the orifice area, and r is the diameter of the tip of the gun;

[0136] ξ is the local loss coefficient, which is related to S o and S2, the smaller the ratio, the larger ξ, then it can be simplified to:

[0137]

[0138] Г is a parameter related to P, V, and T of the air in space, and this parameter can be regarded as a constant value from t to t + dt;

[0139]

[0140] S2 is the area of the gun mounting opening;

[0141] Substituting Equations (8) and (9) into (7) gives:

[0142]

[0143] From Conclusion [2], it can be seen that:

[0144]

[0145] For pipette tips of 300 μl and 1000 μl, let the outlet area of the 300 μl pipette tip be S o3 , and the outlet area of the 1000 μl pipette tip be S o10

[0146]

[0147] Since S o10 > S o3 , and the amount of air in the space is decreasing, so the value is negative

[0148] Then there is

[0149] From equation (2), list the relational expressions for the 300 μl and 1000 μl pipette tips respectively, and we can get:

[0150]

[0151] Adding the positive and negative relationships of each variable to equation (15) gives:

[0152]

[0153] Similarly, we get:

[0154]

[0155] From relational expressions (3), (4), (14) and (16), (17), it can be seen that:

[0156]

[0157] From conclusion [2] and relational expression (18), it can be seen that the peak air pressure p of the 300 μl pipette tip 3m is greater than the peak air pressure p of the 1000 μl pipette tip 10m

[0158] The above only studies the process of the piston descending to compress the air in the air pressure chamber. When the piston ascends to suck air, the calculation method of its air pressure trough value is similar to the above example. Figure 12 It is the air pressure waveform diagram when the volume of the pipette tip 181 installed on the pneumatic pipettor is 300 μl.

[0159] The above-described embodiments merely represent specific implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the protection scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the technical solution of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application.

Claims

1. A method for a pneumatic pipette to identify pipette tips, the pneumatic pipette comprising: A housing (110), a driving device (130) and a push-pull assembly (170) mounted on the housing (110). A transmission assembly (150), a pressure detection module (190), a processing module (210) and a storage chip are also provided in the housing (110). The push-pull assembly (170) includes a piston tube (173), a piston (175) inserted into the piston tube (173), and a piston rod (171) connected to the piston (175). The inner cavity of the piston tube (173) below the lower end face of the piston (175) forms a cylinder. An installation nozzle (177) is also sleeved on the lower end of the piston tube (173). It is characterized in that the method for identifying a pipette tip includes the following steps: Step S100: Set a reference value. Insert the calibrated pipette tip (181) onto the installation nozzle (177). The cylinder communicates with the inner cavity of the pipette tip (181) to jointly form a pneumatic chamber. The processing module (210) controls the driving device (130) to operate at a set speed, and pushes or / and pulls the piston (175) from one end to the other end in the inner cavity of the piston tube (173) through the transmission assembly (150). During this process, the pressure detection module (190) detects the air pressure value in the pneumatic chamber and writes it into the storage chip. After the air pressure value of a pipette tip (181) of one volume specification is written, replace it with a pipette tip (181) of another calibrated volume specification to obtain the threshold range of the set reference value of pipette tips (181) of various volume specifications and record it in the storage chip; Step S200: Insert the pipette tip (181) to be used onto the installation nozzle (177); Step S300: The processing module (210) controls the driving device (130) to operate at a set speed, and pushes or / and pulls the piston (175) from one end to the other end in the inner cavity of the piston tube (173). During the pushing and pulling process, the pressure detection module (190) detects the air pressure value in the pneumatic chamber, and compares the detected air pressure value with the set reference value of the pipette tip (181) of the corresponding volume specification or model stored in the storage chip; Step S400: When the processing module (210) determines that the detected value falls within the threshold range of the set reference value of the corresponding volume specification or model pre-stored in the storage chip, the processing module (210) determines that the installed pipette tip is the volume specification or model corresponding to the threshold range of the set reference value, and outputs the determination result of the volume specification or model of the pipette tip (181); When judging whether the volume specification or model of the pipette tip (181) is correctly installed, between step S200 and step S300, add step S210, Step S210: Input the volume specification or model information of the pipette tip (181) to be detected; After step S400, add step S500, Step S500: When the detected value is consistent with the set reference value stored in the storage chip corresponding to the volume specification or model in step S210, the processing module (210) determines that the pipette tip (181) is correctly selected and issues a signal indicating correct result or does not issue a signal; when the detected value is inconsistent with the set reference value stored in the storage chip corresponding to the volume specification or model in step S210, the processing module (210) determines that the pipette tip (181) is incorrectly selected and issues a warning signal indicating incorrect result. In steps S100 and S300, the set speed is as follows: the processing module (210) controls the driving device (130) to rotate at a set speed of 20±2 r / s, or the rotation speed of the driving device (130) is controlled such that the air volume change in the air pressure chamber is 17.35±2 ul / r. In steps S100 and S300, the air pressure value includes: the air pressure peak value and / or the air pressure valley value. The processing module (210) controls the piston (175) to push from one end to the other end and / or pull from the other end to one end at least once in the inner cavity of the piston tube (173) to obtain at least one air pressure peak value and / or one air pressure valley value.

2. The method for identifying a pipette tip applicable to a pneumatic pipette according to claim 1, wherein In steps S100 and S300, the air pressure value further includes the waveform curve of the air pressure change between the peak value and the valley value. In step S100, the processing module (210) processes the received air pressure value. The processing method is that the processing module (210) floats all the received air pressure peak values, air pressure valley values and waveform curves upward by 10% and downward by 10% respectively to form the threshold range of each set reference value. In step S300, the processing module (210) compares the detected values of the received air pressure peak value, air pressure valley value and waveform curve with the threshold range of each set reference value to determine whether each detected value is within the threshold range of the corresponding set reference value.

3. A method for identifying pipette tips applicable to a pneumatic pipette according to claim 1, characterized in that, In step S100, the processing module (210) screens the received air pressure values to respectively screen out the maximum value and the minimum value of the air pressure peak value, and the maximum value and the minimum value of the air pressure valley value. The maximum value of the air pressure peak value is floated upward by 10%, and the minimum value of the air pressure peak value is floated downward by 10%. The value range between the air pressure peak value after the minimum value is floated downward by 10% and the air pressure peak value after the maximum value is floated upward by 10% forms the threshold range of the set reference value of the air pressure peak value. The maximum value of the air pressure valley value is floated upward by 10%, and the minimum value of the air pressure valley value is floated downward by 10%. The value range between the air pressure valley value after the minimum value is floated downward by 10% and the air pressure valley value after the maximum value is floated upward by 10% forms the threshold range of the set reference value of the air pressure valley value.

4. A method for identifying pipette tips applicable to a pneumatic pipettor according to claim 3, characterized in that, In step S300, the processing module (210) screens the received air pressure values, screens out each air pressure peak value, takes its average value as the detected air pressure peak value, and compares it with the threshold range of the set reference value of the air pressure peak value to determine whether it falls within the threshold range of the set reference value; screens out each air pressure valley value, takes its average value as the detected air pressure valley value, and compares it with the threshold range of the set reference value of the air pressure valley value to determine whether it falls within the threshold range of the set reference value.

5. A method for identifying pipette tips applicable to a pneumatic pipette according to claim 2 or 4, characterized in that, When the detected air pressure peak value and / or air pressure valley value fall within the threshold range corresponding to the set reference value, the processing module (210) determines that the comparison is consistent, and the pipette tip (181) is correctly installed; when the detected air pressure peak value or / and air pressure valley value is not within the threshold range corresponding to the set reference value, the processing module (210) determines that the comparison is inconsistent, the pipette tip (181) is incorrectly installed, the processing module (210) controls the driving device (130) to pause operation, and controls the warning module (230) to issue a warning message.

6. A method for identifying a pipette tip applicable to a pneumatic pipette according to claim 5, characterized in that, The warning module (230) is installed on the housing (110) and is electrically connected to the processing module (210). The warning module (230) includes a warning light or / and a buzzer, and the warning message is to turn on a red light or / and emit a warning sound.

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