An air displacement pipette pump facilitating the disassembly and assembly of pipette tips

Abstract

The present application relates to the field of quantitative pipetting, and discloses an air displacement pipetting pump facilitating disassembly and assembly of pipette tips, which includes a housing. A piston cylinder is provided at the bottom end of the housing, and a pipette tip is installed at the bottom end of the piston cylinder. A piston rod is slidably arranged in the piston cylinder. A driving mechanism is arranged in the housing, and a needle loading mechanism for automatically loading the pipette tip onto the piston cylinder is arranged on the housing. A needle unloading mechanism is arranged in the housing. The driving mechanism drives the needle unloading mechanism to slide on the piston cylinder, and the needle unloading mechanism pushes the pipette tip away from the piston cylinder. The present application can drive the needle unloading mechanism to move on the piston cylinder by adopting the driving mechanism. The needle unloading mechanism moves and pushes the pipette tip away from the piston cylinder to complete the disassembly of the pipette tip. Then, a new pipette tip is placed on the needle loading mechanism, and the needle loading mechanism moves towards the piston cylinder and drives the pipette tip to be installed on the pipetting pump, realizing automatic disassembly and assembly of the pipette tip, thereby making the disassembly and assembly of the pipette tip more convenient and fast.

Description

Technical Field

[0001] This application relates to the field of quantitative pipetting, and particularly to an air displacement pipetting pump that facilitates the disassembly and assembly of pipette tips. Background Art

[0002] In modern society, infectious diseases occur continuously. To ensure accurate prevention and control, it is necessary to quickly verify suspected cases, and thus a series of automated pipetting equipment must be used to replace the traditional manual method of handling liquid samples.

[0003] Currently, most staff use pipetting pumps to handle liquid samples. The pipette tip is detachably installed at the bottom of the pipetting pump. The pipetting pump first sucks the liquid sample into the pipette tip and then proceeds with the next step of processing. During the verification process, it is often necessary to verify multiple liquid samples. Therefore, it is necessary to frequently disassemble and assemble the pipette tip. In the existing pipetting pump, the staff needs to manually install and remove the pipette tip. When manually installing the pipette tip, it is difficult to judge the firmness of the installation, and the pipette tip is likely to be installed insecurely. When manually removing the pipette tip, if the pipette tip is firmly fixed, it is difficult for the staff to manually remove the pipette tip. Summary of the Invention

[0004] In order to improve the problem of inconvenient disassembly and assembly of the pipette tip of the pipetting pump, this application provides an air displacement pipetting pump that facilitates the disassembly and assembly of the pipette tip.

[0005] The air displacement pipetting pump that facilitates the disassembly and assembly of the pipette tip provided by this application adopts the following technical solutions:

[0006] An air displacement pipetting pump that facilitates the disassembly and assembly of the pipette tip, including a housing. A piston cylinder is provided at the bottom of the housing. The pipette tip is detachably installed at the bottom of the piston cylinder. A piston rod is slidably disposed in the piston cylinder. A driving mechanism for driving the piston rod to reciprocate in the piston cylinder is provided in the housing. A needle loading mechanism for placing the pipette tip and automatically loading the pipette tip onto the piston cylinder is provided on the housing. A needle unloading mechanism is provided in the housing. The driving mechanism drives the needle unloading mechanism to slide on the piston cylinder, and the needle unloading mechanism pushes the pipette tip away from the piston cylinder.

[0007] By adopting the above technical solution, the driving mechanism in the housing drives the piston rod to slide in the piston cylinder, thereby completing the suction and discharge of the liquid sample. When the pipette tip needs to be replaced, the driving mechanism drives the needle unloading mechanism to move in the piston cylinder towards the pipette tip, and the needle unloading mechanism moves and pushes the pipette tip away from the piston cylinder, thereby completing the disassembly of the pipette tip. Then, the staff places a new pipette tip on the needle loading mechanism, and the needle loading mechanism moves towards the piston cylinder, thereby driving the pipette tip to be installed on the liquid transfer pump. With such a setting, the automatic installation and disassembly of the pipette tip are realized by using the driving mechanism, the needle unloading mechanism and the needle loading mechanism, making the disassembly and assembly of the pipette tip more convenient and fast.

[0008] Preferably, the driving mechanism includes a first driving member, a first lead screw, a guide rod and a slider. The first driving member is arranged on the housing, the first lead screw is rotatably arranged in the housing, the axis of the first lead screw is parallel to the axis of the piston cylinder, the guide rod is arranged in the housing and parallel to the first lead screw, the slider is slidably sleeved on the first lead screw and the guide rod along the axis direction of the first lead screw, the slider is in threaded cooperation with the first lead screw, and the piston rod is arranged on the slider.

[0009] By adopting the above technical solution, when sucking the liquid sample, the first driving member drives the first lead screw to rotate, the first lead screw drives the slider to move, and the slider drives the piston rod to slide in the piston cylinder away from the pipette tip, so that the pipette tip can suck the liquid sample; when discharging the liquid sample, the first driving member drives the first lead screw to rotate in the reverse direction, and the first lead screw drives the piston rod to slide in the piston cylinder towards the pipette tip through the slider, so that the pipette tip can discharge the liquid sample. And the guide rod limits the sliding of the slider, making the reciprocating sliding of the piston rod more stable.

[0010] Preferably, the needle unloading mechanism includes a needle unloading push rod and a needle unloading sliding sleeve. The needle unloading push rod is slidably arranged in the housing and is located below the slider. The slider moves and abuts against the needle unloading push rod. The needle unloading sliding sleeve is coaxially slidably arranged on the piston cylinder. The needle unloading push rod slidably penetrates through the housing and is fixedly connected to the needle unloading sliding sleeve. The needle unloading sliding sleeve moves and abuts against the pipette tip.

[0011] By adopting the above technical solution, when the pipette tip needs to be disassembled, the driving mechanism drives the slider to move, the slider moves and pushes the needle unloading push rod to move, and the needle unloading push rod then pushes the needle unloading sliding sleeve to slide on the piston cylinder. The needle unloading sliding sleeve slides towards the pipette tip and pushes the pipette tip away from the piston cylinder. With such a setting, while the driving mechanism realizes the suction and discharge of the liquid sample by the pipette tip, it can also realize the automatic disassembly of the pipette tip through the needle unloading push rod and the needle unloading sliding sleeve, making the disassembly of the pipette tip more convenient and fast.

[0012] Preferably, an elastic member for resetting the needle unloading push rod is arranged inside the housing, and two ends of the elastic member are respectively abutted against the inner wall of the housing and the top of the needle unloading push rod.

[0013] By adopting the above technical solution, when the slider drives the needle unloading push rod to move, the needle unloading push rod drives the elastic member to deform. When the slider moves back to its original position, the elastic member releases its elastic potential energy and drives the needle unloading push rod to move back to its original position, thus facilitating the disassembly of the suction head again.

[0014] Preferably, the needle loading mechanism includes two mounting components symmetrically arranged on both sides of the housing and a mounting block arranged at the ends of the two mounting components. An installation hole for placing the suction head is formed in the mounting block, and the two mounting components drive the mounting block to reciprocate along the axis direction of the piston cylinder block.

[0015] By adopting the above technical solution, when the suction head needs to be installed, the suction head is placed in the installation hole of the mounting block, and the two mounting components drive the mounting block to move towards the piston cylinder block. The installation hole moves and mounts the suction head on the piston cylinder block. With this arrangement, the mounting components are used to install the suction head, and the position of the suction head during each installation is the same, so that the suction head is more stably mounted on the piston cylinder block.

[0016] Preferably, the mounting component includes a second driving member, a second lead screw, a rotating seat, a lifting block, a first connecting rod, a second connecting rod and a third connecting rod. The second driving member is arranged on the housing, the rotating seat is arranged on the outer side wall of the housing, the second lead screw is arranged along the axis direction of the piston cylinder block, and two ends of the second lead screw are respectively rotatably arranged in the housing and the rotating seat. The lifting block is sleeved on the second lead screw and is in threaded cooperation with the second lead screw. The first connecting rod is rotatably arranged on the lifting block, the second connecting rod is rotatably arranged on the rotating seat, the third connecting rod is rotatably arranged on the mounting block, the rotating seat is located between the lifting block and the mounting block, and the ends of the first connecting rod, the second connecting rod and the third connecting rod close to each other are rotatably connected.

[0017] By adopting the above technical solution, when the two second driving members operate together, the two second driving members drive the two second lead screws to rotate together, and the two second lead screws drive the two lifting blocks to lift together. The two lifting blocks drive the mounting block to move along the axis direction of the driving piston through the cooperation of the two first connecting rods, the second connecting rod and the third connecting rod, so that the needle mounting mechanism can automatically complete the installation of the suction head; when one second driving member operates alone, one second driving member drives one second lead screw to rotate, one second lead screw drives one lifting block to lift, and one lifting block drives the mounting block to move along the diameter direction of the driving piston through the cooperation of the two first connecting rods, the second connecting rod and the third connecting rod, so that the needle mounting mechanism can automatically offset. At this time, the mounting block is located obliquely below the piston cylinder body, so that the mounting block will not affect the disassembly of the suction head.

[0018] Preferably, a vent hole communicating with the inner cavity of the piston cylinder is provided on the housing. A circuit board is detachably provided on the side wall of the housing. A pressure sensor is provided on the circuit board. The pressure sensor is arranged in the vent hole. A first sealing ring is provided on the pressure sensor, and the first sealing ring seals between the pressure sensor and the housing.

[0019] By adopting the above technical solution, when sucking a liquid sample, the pressure sensor on the circuit board can detect the air pressure in the piston cylinder, so as to record and feedback the situation of the liquid level of the liquid to be measured in the suction head, making the liquid transfer pump suck the liquid sample more accurately. And the first sealing ring seals between the pressure sensor and the housing, thereby improving the detection result of the pressure sensor.

[0020] Preferably, a first photoelectric switch and a second photoelectric switch electrically connected to the first driving member are provided on the circuit board. The slider slides past the first photoelectric switch and controls the shutdown of the first driving member. A light-shielding plate is provided on the needle unloading sleeve, and the light-shielding plate slides past the second photoelectric switch and controls the shutdown of the first driving member.

[0021] By adopting the above technical solution, the slider pushes the needle unloading sleeve to move through the needle unloading push rod and disassembles the suction head. When the slider moves into the first photoelectric switch, the slider blocks the infrared ray of the first photoelectric switch, and the first photoelectric switch changes from a light-transmitting state to a light-shielding state. At this time, the first photoelectric switch controls the first driving member to stop operating; the movement of the needle unloading sleeve drives the light-shielding plate to move, and the light-shielding plate blocks the infrared ray of the second photoelectric switch. When the light-shielding plate slides out of the second photoelectric switch, the second photoelectric switch changes from a light-shielding state to a light-transmitting state. At this time, the second photoelectric switch controls the first driving member to stop operating. By setting like this, the first photoelectric switch and the second photoelectric switch are used to limit the moving stroke of the slider and the needle unloading sleeve, so as to avoid pushing the needle unloading sleeve out excessively.

[0022] Preferably, a second sealing ring is provided at the connection between the housing and the piston cylinder block, and a third sealing ring is provided at the connection between the housing and the piston rod.

[0023] By adopting the above technical solution, the second sealing ring increases the sealing performance between the housing and the piston cylinder block, and the third sealing ring increases the sealing performance between the housing and the piston rod, making the sealing of the inner cavity of the piston cylinder block better, thereby further improving the accuracy of the liquid transfer pump for sucking liquid samples.

[0024] Preferably, a sealing gasket ring is sleeved on the piston rod, a sealing gland is arranged in the housing, the piston rod slides through the sealing gland, and the sealing gland presses the sealing gasket ring in the housing.

[0025] By adopting the above technical solution, the sealing gland presses the sealing gasket ring in the housing, and the sealing gasket ring seals between the piston rod and the housing, thereby further improving the sealing of the inner cavity of the piston cylinder block.

[0026] In summary, the present application includes at least one of the following beneficial technical effects:

[0027] 1. By adopting the needle removal mechanism and the needle loading mechanism, when the pipette tip needs to be replaced, the driving mechanism drives the needle removal mechanism to move in the piston cylinder block towards the pipette tip, the needle removal mechanism moves and pushes the pipette tip away from the piston cylinder block to complete the removal of the pipette tip, then a new pipette tip is placed on the needle loading mechanism, and the needle loading mechanism moves towards the piston cylinder block, thereby driving the pipette tip to be installed on the liquid transfer pump, realizing the automatic installation and automatic removal of the pipette tip, and making the disassembly and assembly of the pipette tip more convenient and fast;

[0028] 2. By adopting the air pressure sensor, when sucking the liquid sample, the air pressure sensor on the circuit board can detect the air pressure in the piston cylinder block, thereby recording and feeding back the situation of the liquid level of the liquid to be measured in the pipette tip, making the liquid transfer pump suck the liquid sample more accurately;

[0029] 3. By adopting the first photoelectric switch and the second photoelectric switch to limit the moving stroke of the slider and the needle removal sliding sleeve, the needle removal sliding sleeve is prevented from being pushed out excessively. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the overall structural schematic diagram of the air displacement type liquid transfer pump of the present application;

[0031] Figure 2 is the overall structural explosion diagram of the air displacement type liquid transfer pump of the present application;

[0032] Figure 3 is the partial structural sectional view of the air displacement type liquid transfer pump of the present application highlighting the driving mechanism;

[0033] Figure 4It is a partial structural sectional view of the air displacement pipette pump of the present application;

[0034] Figure 5 It is the present application Figure 4 The enlarged schematic view at position A in it;

[0035] Figure 6 It is a partial structural schematic view of the air displacement pipette pump of the present application for prominently showing the needle mounting mechanism;

[0036] Figure 7 It is a partial structural schematic view of the air displacement pipette pump of the present application for prominently showing the offset state of the mounting block;

[0037] Figure 8 It is a partial structural schematic view of the air displacement pipette pump of the present application for prominently showing the circuit board.

[0038] Explanation of reference numerals: 1. Housing; 2. Piston cylinder block; 3. Pipette tip; 4. Piston rod; 5. Driving mechanism; 51. First driving member; 52. First lead screw; 53. Guide rod; 54. Slide block; 541. Moving part; 542. Threaded sleeve; 6. Needle mounting mechanism; 61. Mounting assembly; 611. Second driving member; 612. Second lead screw; 613. Rotating seat; 614. Lifting block; 615. First connecting rod; 616. Second connecting rod; 617. Third connecting rod; 62. Mounting block; 7. Needle discharging mechanism; 71. Needle discharging push rod; 72. Needle discharging sliding sleeve; 8. Elastic member; 9. Mounting hole; 10. Vent hole; 11. Pressure sensor; 12. First sealing ring; 13. Circuit board; 14. First optoelectronic switch; 15. Second optoelectronic switch; 16. Light shielding plate; 17. Second sealing ring; 18. Third sealing ring; 19. Sealing gasket ring; 20. Sealing gland; 21. Outer cover; 22. Connecting bolt; 23. Light shielding part; 24. Rotating shaft. Detailed implementation manners

[0039] The following further elaborates on the present application in conjunction with the attached Figure 1-8 for a more detailed description.

[0040] The embodiment of the present application discloses an air displacement pipette pump that is convenient for disassembling and assembling the pipette tip.

[0041] Refer to Figure 1 and 2, An air displacement pipette pump facilitating the disassembly and assembly of the pipette tip includes a housing 1. A cavity is formed inside the housing 1. A piston cylinder 2 communicating with the cavity of the housing 1 is integrally formed on the bottom wall of the housing 1 in the vertical direction. A pipette tip 3 is detachably installed at the bottom end of the piston cylinder 2. A piston rod 4 is slidably installed in the inner cavity of the housing 1. The piston rod 4 is sealingly connected to the housing 1. At the same time, the piston rod 4 is coaxially and slidably installed in the piston cylinder 2. A driving mechanism 5 is installed in the cavity of the housing 1. The driving mechanism 5 drives the piston rod 4 to reciprocally slide in the piston cylinder 2. When the pipette tip 3 enters the liquid sample, a sealed chamber is formed in the piston cylinder 2. The driving mechanism 5 drives the piston rod 4 to move upward or downward, so that a pressure difference is formed between the air pressure in the sealed chamber and the external air pressure. Then, the external atmospheric pressure presses the liquid sample into the pipette tip 3 or presses the liquid sample out of the pipette tip 3, thereby completing the sampling process of the liquid sample.

[0042] Referring to Figure 3 and 4 , the driving mechanism 5 includes a first driving member 51, a first lead screw 52, a guide rod 53 and a slider 54. The first driving member 51 is fixedly installed on the top wall of the housing 1. The first lead screw 52 is rotatably installed in the cavity of the housing 1 through a bearing. The first lead screw 52 is installed in the vertical direction and fixedly connected to the driving shaft of the first driving member 51. In this application, the first driving member 51 can be selected as a servo motor, and the first driving member 51 can drive the first lead screw 52 to reciprocally rotate in the housing 1. The guide rod 53 is fixedly installed in the cavity of the housing 1, and the guide rod 53 is parallel to the lead screw.

[0043] The slider 54 includes a moving part 541 and a threaded sleeve 542. The threaded sleeve 542 is sleeved on the first lead screw 52. The moving part 541 is fixedly installed on the threaded sleeve 542 through bolts. The top end of the piston rod 4 is fixedly connected to the moving part 541, and the moving part 541 is slidably installed on the guide rod 53 along the axis direction of the guide rod 53 through a bushing. During the reciprocating rotation of the first lead screw 52, the threaded sleeve 542 is driven to reciprocally move along the axis direction of the lead screw. The threaded sleeve 542 drives the piston rod 4 to reciprocally move through the moving part 541, thereby sucking and discharging the liquid sample. At the same time, the guide rod 53 limits the movement of the moving part 541, making the movement of the moving part 541 driving the piston rod 4 more stable.

[0044] Referring to Figure 3, inside the housing 1, there is a needle unloading mechanism 7 for automatically disassembling the suction head 3. The needle unloading mechanism 7 includes a needle unloading push rod 71 and a needle unloading sliding sleeve 72. The needle unloading push rod 71 is slidably installed in the housing 1 in the vertical direction, and the bottom end of the needle unloading push rod 71 slidably penetrates the bottom of the housing 1. The needle unloading sliding sleeve 72 is slidably sleeved on the piston cylinder block 2 in the vertical direction, and the top end of the needle unloading sliding sleeve 72 is fixedly connected to the bottom end of the needle unloading push rod 71. When the first driving member 51 drives the moving part 541 to move downward, the bottom wall of the moving part 541 abuts against the top end of the needle unloading push rod 71 and pushes the needle unloading push rod 71 to move downward. The needle unloading push rod 71 drives the needle unloading sliding sleeve 72 to slide on the piston cylinder block 2 towards the suction head 3, and the needle unloading sliding sleeve 72 slides and pushes the suction head 3 away from the piston cylinder block 2. In this way, the suction head 3 can be automatically disassembled, making the disassembly of the suction head 3 more convenient and fast.

[0045] An elastic member 8 is sleeved on the rod body of the needle unloading push rod 71 at the cavity of the housing 1. The width of the top end of the needle unloading push rod 71 is greater than the width of the rod body of the needle unloading push rod 71. One end of the elastic member 8 abuts against the bottom wall of the top end of the needle unloading push rod 71, and the other end abuts against the bottom wall of the inner cavity of the housing 1. In this application, the elastic member 8 can be selected as a spring. When the needle unloading push rod 71 moves downward, the needle unloading push rod 71 squeezes the elastic member 8 and causes the elastic member 8 to deform. When the suction head 3 is separated from the piston cylinder block 2 and the moving part 541 moves upward, the elastic member 8 releases elastic potential energy and pushes the needle unloading push rod 71 to move upward and reset, thus facilitating the automatic disassembly of the next suction head 3.

[0046] Refer to Figure 6 and 7 , on the housing 1, there is a needle loading mechanism 6 for automatically installing the suction head 3. The needle loading mechanism 6 includes two installation components 61 and an installation block 62. The two installation components 61 are symmetrically installed on the two pairs of side walls of the housing 1 in the horizontal direction, and the installation block 62 is installed at the bottom ends of the two installation components 61 and is located below the piston cylinder block 2. An installation hole 9 is formed in the middle of the installation block 62, and the suction head 3 is placed in the installation hole 9. The two installation components 61 can drive the installation block 62 to move, so as to install the suction head 3 on the piston cylinder block 2.

[0047] The installation component 61 includes a second driving member 611, a second lead screw 612, a rotating seat 613, a lifting block 614, a first connecting rod 615, a second connecting rod 616, and a third connecting rod 617. The second driving member 611 is fixedly installed at the top of the housing 1 and is located beside the first driving member 51. The rotating seat 613 is integrally formed at the bottom end of the side wall of the housing 1 and is located directly below the second driving member 611. The second lead screw 612 is rotatably installed on the rotating seat 613 through a bearing. The second lead screw 612 is installed in the vertical direction, and the top end of the second lead screw 612 is fixedly connected to the driving shaft of the second driving member 611. In this application, the second driving member 611 can be selected as a servo motor, and the second driving member 611 drives the second lead screw 612 to rotate reciprocally on the rotating seat 613.

[0048] The lifting block 614 is threadedly sleeved on the second lead screw 612. There are two of each of the first connecting rod 615, the second connecting rod 616, and the third connecting rod 617. The two first connecting rods 615 are rotatably installed on the opposite side walls of the lifting block 614. The two second connecting rods 616 are rotatably installed on the opposite side walls of the rotating seat 613. The two third connecting rods 617 are rotatably installed on the opposite side walls of the mounting block 62. The ends of the first connecting rod 615, the second connecting rod 616, and the third connecting rod 617 that are close to each other are rotatably connected through a rotating shaft 24, and a set of the first connecting rod 615, the second connecting rod 616, and the third connecting rod 617 is parallel to another set of the first connecting rod 615, the second connecting rod 616, and the third connecting rod 617.

[0049] The two second lead screws 612 rotate and drive the two lifting blocks 614 to descend. When the two lifting blocks 614 descend together, the lifting block 614 drives the first connecting rod 615 to move downward. The first connecting rod 615 drives the third connecting rod 617 to move downward through the cooperation of the second connecting rod 616. The downward movement of the two third connecting rods 617 can drive the mounting block 62 to move downward (the position of the mounting block 62 is for reference Figure 6 ). Place the suction head 3 in the mounting hole 9 of the mounting block 62, and then the two second lead screws 612 rotate in the reverse direction. The mounting block 62 rises and automatically installs the suction head 3 on the piston cylinder block 2 (the position of the mounting block 62 is for reference Figure 1 ). Using the installation component 61 to install the suction head 3, the position of the suction head 3 during each installation is the same, so that the suction head 3 is installed more stably on the piston cylinder block 2.

[0050] After the suction head 3 is installed, the two lifting blocks 614 descend and drive the mounting block 62 to descend. After the mounting block 62 descends and the suction head 3 is completely separated from the mounting block 62, a second lead screw 612 rotates independently and drives the lifting block 614 to ascend. At this time, the lifting block 614 drives the first connecting rod 615 inside this mounting assembly 61 to ascend. The first connecting rod 615 drives the mounting block 62 to move along the diameter direction of the drive piston through the second connecting rod 616, the third connecting rod 617 inside this mounting assembly 61, and the third connecting rod 617 inside another mounting assembly 61, so that the needle mounting mechanism 6 can automatically offset after the suction head 3 is installed (the position reference of the mounting block 62 Figure 7 ). At this time, the mounting block 62 is located diagonally below the piston cylinder block 2, so that when the suction head is disassembled, the mounting block 62 will not interfere with the suction head 3.

[0051] Refer to Figure 2 , 5 and 8, a circuit board 13 is installed on one side of the open end of the cavity of the housing 1. A pressure sensor 11 is installed on the circuit board 13. A ventilation hole 10 is opened on the side wall of the housing 1 close to the circuit board 13. The ventilation hole 10 is communicated with the inner cavity of the piston cylinder block 2. When the circuit board 13 is installed on the side wall of the housing 1, the pressure sensor 11 is inserted into the ventilation hole 10 of the housing 1. When sucking a liquid sample, the pressure sensor 11 on the circuit board 13 can detect the air pressure in the piston cylinder block 2, so as to record and feedback the situation of the liquid level of the liquid to be measured in the suction head 3, making the liquid transfer pump suck the liquid sample more accurately.

[0052] Refer to Figure 2 and 4 , the side of the circuit board 13 away from the housing 1 is installed with an outer cover 21 through a connecting bolt 22. The outer cover 21 covers the circuit board 13 to protect the circuit board 13 so that the circuit board 13 is not easily damaged.

[0053] Refer to Figure 5 and 8, a first sealing ring 12 is sleeved on the air pressure sensor 11. The first sealing ring 12 is installed in the ventilation hole 10, and the first sealing ring 12 seals between the air pressure sensor 11 and the housing 1; a second sealing ring 17 is installed in the housing 1. The second sealing ring 17 is located at the connection between the housing 1 and the piston cylinder block 2, and the second sealing ring 17 seals between the piston cylinder block 2 and the housing 1; a third sealing ring 18 is installed in the housing 1. The third sealing ring 18 is located between the housing 1 and the piston rod 4, and the third sealing ring 18 seals between the housing 1 and the piston rod 4. In this application, both the first sealing ring 12 and the third sealing ring 18 can be selected as nitrile rubber O-rings, and the second sealing ring 17 can be selected as a hydrogenated nitrile rubber O-ring. The first sealing ring 12, the second sealing ring 17 and the third sealing ring 18 are used to seal the inner cavity of the piston cylinder block 2, so that the liquid sample can be more accurately sucked by the pipette pump.

[0054] Refer to Figure 5 , a sealing gasket ring 19 is sleeved on the piston rod 4 in a sealed manner. The third sealing ring 18 is sleeved on the sealing gasket ring 19. The sealing gasket ring 19 abuts against the bottom wall of the cavity of the housing 1. A sealing gland 20 is fixedly installed on the bottom wall of the cavity of the housing 1 through bolts. The sealing gland 20 presses the sealing gasket ring 19 tightly in the housing 1. In this application, the sealing gasket ring 19 can be selected as a rubber gasket ring. The sealing gasket ring 19 cooperates with the third sealing ring 18 to seal the connection between the housing 1 and the piston rod 4, thereby further improving the sealing performance of the piston cylinder block 2.

[0055] Refer to Figure 3 , at the same time, the needle unloading push rod 71 slides through the sealing gland 20. The sealing gland 20 limits the movement of the needle unloading push rod 71, so that the needle unloading push rod 71 slides more stably in the housing 1.

[0056] Refer to Figure 4 and 8 , a first photoelectric switch 14 is installed above the air pressure sensor 11 on the circuit board 13, and a second photoelectric switch 15 is installed below the air pressure sensor 11 on the circuit board 13. Both the first photoelectric switch 14 and the second photoelectric switch 15 are electrically connected to the first driving member 51. In this application, both the first photoelectric switch 14 and the second photoelectric switch 15 can be selected as U-shaped photoelectric switches, and the open ends of the U-shaped photoelectric switches face the housing 1.

[0057] An end of the moving part 541 close to the circuit board 13 is integrally formed with a light-shielding part 23 that can slide past the first optoelectronic switch 14, and a light-shielding plate 16 that can slide past the second optoelectronic switch 15 is integrally formed on one side of the top end of the needle-removing sliding sleeve 72 close to the circuit board 13. During the process of disassembling the suction head 3, the moving part 541 drives the light-shielding part 23 to move downward. When the light-shielding part 23 moves into the first optoelectronic switch 14, the light-shielding part 23 blocks the infrared ray of the first optoelectronic switch 14, and the first optoelectronic switch 14 changes from a light-transmitting state to a light-shielding state. At this time, the first optoelectronic switch 14 controls the first driving member 51 to stop operating; during the process of disassembling the suction head 3, the needle-removing sliding sleeve 72 drives the light-shielding plate 16 to move downward. When the light-shielding plate 16 is in the initial state, it blocks the infrared ray of the second optoelectronic switch 15. When the light-shielding plate 16 slides out of the second optoelectronic switch 15, the second optoelectronic switch 15 changes from a light-shielding state to a light-transmitting state. At this time, the second optoelectronic switch 15 controls the first driving member 51 to stop operating. In this way, the first optoelectronic switch 14 and the second optoelectronic switch 15 are used to limit the moving stroke of the slider 54 and the needle-removing sliding sleeve 72, so as to avoid pushing the needle-removing sliding sleeve 72 out excessively.

[0058] The implementation principle of the embodiment of the present application is as follows: when the suction head 3 enters the liquid sample, a closed chamber is formed in the piston cylinder body 2. The driving mechanism 5 drives the piston rod 4 to move upward or downward, so that a pressure difference is formed between the air pressure in the closed chamber and the external air pressure. Then the external atmospheric pressure presses the liquid sample into the suction head 3 or presses the liquid sample out of the suction head 3, thereby completing the sampling process of the liquid sample. When it is necessary to disassemble the suction head 3, when the first driving member 51 drives the moving part 541 to move downward, the bottom wall of the moving part 541 abuts against the top end of the needle-removing push rod 71 and pushes the needle-removing push rod 71 to move downward. The needle-removing push rod 71 drives the needle-removing sliding sleeve 72 to slide on the piston cylinder body 2 in the direction close to the suction head 3, and the needle-removing sliding sleeve 72 slides and pushes the suction head 3 away from the piston cylinder body 2; when it is necessary to install the suction head 3, a new suction head 3 is placed into the installation hole 9 of the installation block 62, and two second driving members 611 drive two second lead screws 612 to rotate. The two second lead screws 612 drive the installation block 62 to rise through the lifting block 614, the first connecting rod 615, the second connecting rod 616 and the third connecting rod 617 and automatically install the suction head 3 on the piston cylinder body 2, realizing the automatic installation and automatic disassembly of the suction head 3, so that the disassembly and assembly of the suction head 3 are more convenient and fast.

[0059] The above are all the preferred embodiments of the present application, and the protection scope of the present application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.

Claims

1. An air displacement pipette pump facilitating disassembly and assembly of a pipette tip, comprising a housing (1), a piston cylinder body (2) is arranged at the bottom end of the housing (1), a pipette tip (3) is detachably installed at the bottom end of the piston cylinder body (2), a piston rod (4) is slidably arranged in the piston cylinder body (2), and it is characterized in that: A driving mechanism (5) for driving a piston rod (4) to reciprocate in a piston cylinder block (2) is arranged in the housing (1). A needle loading mechanism (6) for placing a suction head (3) and automatically loading the suction head (3) onto the piston cylinder block (2) is arranged on the housing (1). A needle unloading mechanism (7) is arranged in the housing (1). The driving mechanism (5) drives the needle unloading mechanism (7) to slide on the piston cylinder block (2), and the needle unloading mechanism (7) pushes the suction head (3) to disengage from the piston cylinder block (2). The needle loading mechanism (6) includes two mounting components (61) symmetrically arranged on both sides of the housing (1) and a mounting block (62) arranged at the ends of the two mounting components (61). An installation hole (9) for placing the suction head (3) is formed in the mounting block (62), and the two mounting components (61) drive the mounting block (62) to reciprocate along the axial direction of the piston cylinder block (2). The mounting component (61) includes a second driving member (611), a second lead screw (612), a rotating seat (613), a lifting block (614), a first connecting rod (615), a second connecting rod (616) and a third connecting rod (617). The second driving member (611) is arranged on the housing (1), the rotating seat (613) is arranged on the outer side wall of the housing (1), the second lead screw (612) is arranged along the axial direction of the piston cylinder block (2), and two ends of the second lead screw (612) are respectively rotatably arranged in the housing (1) and the rotating seat (613). The lifting block (614) is sleeved on the second lead screw (612) and is in threaded cooperation with the second lead screw (612). The first connecting rod (615) is rotatably arranged on the lifting block (614), the second connecting rod (616) is rotatably arranged on the rotating seat (613), the third connecting rod (617) is rotatably arranged on the mounting block (62), the rotating seat (613) is located between the lifting block (614) and the mounting block (62), and the ends of the first connecting rod (615), the second connecting rod (616) and the third connecting rod (617) close to each other are rotatably connected.

2. The air displacement pipette pump facilitating disassembly and assembly of a pipette tip according to claim 1, characterized in that: The driving mechanism (5) includes a first driving member (51), a first lead screw (52), a guide rod (53) and a slider (54). The first driving member (51) is arranged on the housing (1), the first lead screw (52) is rotatably arranged in the housing (1), the axis of the first lead screw (52) is parallel to the axis of the piston cylinder block (2), the guide rod (53) is arranged in the housing (1) and is parallel to the first lead screw (52), the slider (54) is slidably sleeved on the first lead screw (52) and the guide rod (53) along the axial direction of the first lead screw (52), the slider (54) is in threaded cooperation with the first lead screw (52), and the piston rod (4) is arranged on the slider (54).

3. The air displacement pipette pump according to claim 2, which is convenient for disassembling and assembling the pipette tip, is characterized in that: The needle unloading mechanism (7) includes a needle unloading push rod (71) and a needle unloading sliding sleeve (72). The needle unloading push rod (71) is slidably disposed in the housing (1) and is located below the slider (54). The slider (54) moves and abuts against the needle unloading push rod (71). The needle unloading sliding sleeve (72) is coaxially slidably disposed on the piston cylinder block (2). The needle unloading push rod (71) slidably penetrates through the housing (1) and is fixedly connected to the needle unloading sliding sleeve (72). The needle unloading sliding sleeve (72) moves and abuts against the suction head (3).

4. The air displacement pipette pump facilitating disassembly and assembly of a pipette tip according to claim 3, characterized in that: An elastic member (8) for resetting the needle unloading push rod (71) is disposed in the housing (1). Two ends of the elastic member (8) respectively abut against the inner wall of the housing (1) and the top of the needle unloading push rod (71).

5. The air displacement pipette pump facilitating disassembly and assembly of a pipette tip according to claim 3, wherein: A ventilation hole (10) communicating with the inner cavity of the piston cylinder block (2) is formed in the housing (1). A circuit board (13) is detachably disposed on the side wall of the housing (1). A pressure sensor (11) is disposed on the circuit board (13). The pressure sensor (11) is disposed in the ventilation hole (10). A first sealing ring (12) is disposed on the pressure sensor (11). The first sealing ring (12) seals between the pressure sensor (11) and the housing (1).

6. The air displacement pipette pump facilitating disassembly and assembly of the pipette tip according to claim 5, characterized in that: A first optoelectronic switch (14) and a second optoelectronic switch (15) electrically connected to the first driving member (51) are disposed on the circuit board (13). The slider (54) slides past the first optoelectronic switch (14) and controls the closing of the first driving member (51). A light shielding plate (16) is disposed on the needle unloading sliding sleeve (72). The light shielding plate (16) slides past the second optoelectronic switch (15) and controls the closing of the first driving member (51).

7. The air displacement pipette pump facilitating the disassembly and assembly of a pipette tip according to claim 1, characterized in that: A second sealing ring (17) is disposed at the connection between the housing (1) and the piston cylinder block (2). A third sealing ring (18) is disposed at the connection between the housing (1) and the piston rod (4).

8. The air displacement pipette pump facilitating disassembly and assembly of the pipette tip according to claim 1, characterized in that: A sealing gasket ring (19) is sleeved on the piston rod (4). A sealing gland (20) is disposed in the housing (1). The piston rod (4) slidably penetrates through the sealing gland (20), and the sealing gland (20) presses the sealing gasket ring (19) tightly in the housing (1).

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