Liquid detection device of pipette

Abstract

The utility model discloses a liquid detection device of a pipette. The liquid detection device comprises a pipette tip, a piston air pump, a pressure air pump, an air pressure sensor and a controller, the pipetting tip comprises an inlet end and an outlet end which are oppositely arranged, and the outlet end is used for being in contact with liquid; the piston air pump is communicated with the pipetting suction head and is used for generating air pressure for sucking liquid into the pipetting suction head or discharging the liquid out of the pipetting suction head; the pressure air pump is communicated with the pipetting suction head and is used for generating gas pressure with adjustable duration in the pipetting suction head; the air pressure sensor is connected in an air path formed by the pipetting suction head and the pressure air pump and is used for detecting the air pressure in the air path; and the controller is electrically connected with the air pressure sensor and is used for judging whether the pipetting suction head is in contact with liquid or not according to a detection signal of the air pressure sensor. The pressure air pump is additionally arranged, the pressure air pump can generate gas pressure with adjustable duration, airflow can be generated for a long time, the limitation that a piston air pump is limited by the stroke during liquid detection is broken through, and the liquid detection requirements of different heights of reagent liquid levels can be met.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid transfer guns, in particular to a liquid detection device for a liquid transfer gun. Background Art

[0002] A pipette is a type of pipette, which is often used to transfer small or trace amounts of liquid in laboratories and is a precision instrument.

[0003] In order to determine the exact liquid level of the liquid to be transferred and improve the accuracy of the experimental operation, a liquid detection device for a liquid transfer gun is usually used to detect the liquid to be transferred. Figure 1 As shown, it includes a pipette tip 1, a piston air pump 2 and an air pressure sensor 3. The piston air pump 2 generates an airflow with a certain pressure, which enters the pipette tip 1 and is discharged from the muzzle of the pipette tip 1. The air pressure sensor 3 detects the air path pressure entering the pipette tip 1. When the airflow is discharged from the muzzle of the pipette tip 1, if the muzzle contacts the reagent liquid surface, the air path has resistance, and the air pressure will change stepwise. The magnitude of the air pressure change is used to determine whether the muzzle contacts the reagent liquid surface, and the liquid level detection is completed. However, for liquids with strong viscosity, the bubbles of the liquid can also cause resistance in the air path when they contact the muzzle, resulting in errors in liquid detection; the piston air pump 2 is similar to the piston of a syringe, and has the functions of sucking and discharging liquid and detecting liquid. The actions of detecting liquid and discharging liquid are the same, and both are pistons moving downward, so they will be limited by the piston stroke. When the stroke is completed, airflow cannot be generated, and the change of air path pressure cannot be detected, resulting in failure of liquid detection.

[0004] Therefore, it is necessary to improve the prior art to overcome the above defects in the prior art. Utility Model Content

[0005] The utility model aims to provide a liquid detection device for a liquid transfer gun, which can generate airflow for a long time to meet the liquid detection needs at different heights.

[0006] In order to achieve the above-mentioned utility model object, the utility model proposes a liquid detection device for a liquid transfer gun, comprising:

[0007] A pipette tip, comprising an inlet end and an outlet end arranged opposite to each other, wherein the outlet end is used for contacting the liquid;

[0008] A piston air pump, connected to the pipette tip, for generating air pressure to draw the liquid into or out of the pipette tip;

[0009] A pressure air pump, connected to the pipette tip, for generating a gas pressure of adjustable duration in the pipette tip;

[0010] an air pressure sensor connected to the air circuit formed by the pipette tip and the pressure air pump, and used for detecting the air pressure in the air circuit; and

[0011] The controller is electrically connected to the air pressure sensor and is used to determine whether the pipette tip is in contact with the liquid according to a detection signal of the air pressure sensor.

[0012] Further, the pressure air pump and the pipette tip are connected through a first pipeline, and the piston air pump and the pipette tip are connected through a second pipeline;

[0013] The air pressure sensor is connected to the first pipeline and is used to detect the air pressure in the first pipeline; or,

[0014] The air pressure sensor is connected to the pipette tip and is used to detect the air pressure in the pipette tip.

[0015] Furthermore, it also includes a third pipeline connected to the pipette tip, and the pressure air pump and the piston air pump are connected to the third pipeline through a fourth pipeline and a fifth pipeline respectively;

[0016] The air pressure sensor is connected to the third pipeline and is used to detect the air pressure in the third pipeline; or,

[0017] The air pressure sensor is connected to the fourth pipeline and is used to detect the air pressure in the fourth pipeline; or,

[0018] The air pressure sensor is connected to the pipette tip and is used to detect the air pressure in the pipette tip.

[0019] Furthermore, the pipette tip is made of a conductive material, and is connected to a capacitive sensor for collecting a capacitance value of the pipette tip.

[0020] Furthermore, the controller is electrically connected to the piston air pump, the pressure air pump, the air pressure sensor and the capacitive sensor. The controller is a single chip microcomputer or a PLC, which is used to control the operation of the piston air pump and the pressure air pump according to the detection signals of the air pressure sensor and the capacitive sensor.

[0021] Furthermore, if the air pressure value detected by the air pressure sensor jumps and the capacitance value detected by the capacitance sensor changes, it indicates that the pipette tip is in contact with the liquid; if the air pressure value jumps and the capacitance value remains unchanged, it indicates that the pipette tip is in contact with the bubbles in the liquid.

[0022] Furthermore, it also includes a driving device electrically connected to the controller, the driving device is connected to the pipette tip, and is used to drive the pipette tip to perform lifting movement according to the instructions of the controller.

[0023] Furthermore, the outlet end of the pipette tip is conical.

[0024] Furthermore, the gas pressure generated by the pressure air pump is adjustable.

[0025] Furthermore, the pressure air pump is an impeller pump.

[0026] Compared with the prior art, the utility model has the following beneficial effects: the liquid detection device of the pipette provided by the utility model is additionally provided with a pressure air pump, which can generate gas pressure with adjustable duration and can generate airflow for a long time, thus breaking the limitation of the piston air pump being restricted by stroke when detecting liquid and being able to meet the detection needs of liquids at different heights of the reagent liquid level. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a connection block diagram of a liquid detection device of a liquid transfer gun in the prior art;

[0028] Figure 2 This is a connection block diagram of a liquid detection device for a liquid transfer gun according to an embodiment of the present utility model;

[0029] Figure 3 It is a connection block diagram of a liquid detection device for a liquid transfer gun according to another embodiment of the present utility model;

[0030] Figure 4 It is a connection block diagram of a liquid detection device for a liquid transfer gun according to another embodiment of the present utility model;

[0031] Figure 5 It is a connection block diagram of a liquid detection device for a liquid transfer gun according to another embodiment of the present utility model;

[0032] Figure 6 It is a connection block diagram of a liquid detection device for a liquid transfer gun according to another embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0034] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0035] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0036] like Figures 2 to 6 As shown, the present application provides a liquid detection device for a pipette gun, which is used for liquid level detection of a liquid. The liquid detection device for a pipette gun includes a pipette tip 1, a piston air pump 2, an air pressure sensor 3, a pressure air pump 4 and a controller 5.

[0037] The pipette tip 1 comprises an inlet end 101 and an outlet end 102 which are arranged opposite to each other. The outlet end 102 is used for contacting the liquid. When aspirating the liquid, the outlet end 102 of the pipette tip 1 extends into the liquid to aspirate the liquid.

[0038] The piston air pump 2 is connected to the pipette tip 1 and is used to generate air pressure to suck liquid into or out of the pipette tip 1 .

[0039] The pressure air pump 4 is connected to the pipette tip 1 and is used to generate gas pressure of adjustable duration in the pipette tip 1. Specifically, the pressure air pump 4 is connected to the pipette tip 1 through a pipeline, and a certain amount of gas pressure is generated in the pipette tip 1 by continuously inputting airflow into the pipette tip 1.

[0040] The air pressure sensor 3 is connected to the air circuit formed by the pipette tip 1 and the pressure air pump 4, and is used to detect the air pressure in the air circuit. It can be understood that the air circuit includes a pipeline connected between the air pressure sensor 3 and the pipette tip 1 and a space inside the pipette tip 1. The air pressure sensor 3 can detect the air pressure of the air circuit by detecting the air pressure in the pipeline or detecting the air pressure in the pipette tip 1.

[0041] The controller 5 is electrically connected to the air pressure sensor 3 and is used to determine whether the pipette tip 1 is in contact with the liquid according to the detection signal of the air pressure sensor 3 .

[0042] The piston air pump 2 has a certain stroke, because it is limited by the piston stroke, the air flow time is equal to the piston stroke time, that is, it is impossible to generate gas pressure for a long time, so the distance of the liquid exploration is limited. The pressure air pump 4 is used to generate the gas pressure of adjustable duration, and the air pressure time becomes controllable. As long as the pressure air pump 4 has electrical energy to work, the air pressure continues, that is, the pressure air pump 4 generates the gas pressure of adjustable duration, and can generate airflow for a long time to meet the liquid exploration needs of different heights of the reagent liquid level. In certain embodiments, the pressure air pump 4 is powered by a motor, and the motor only needs to rotate to generate air pressure. The pressure air pump 4 can be, for example, an impeller pump, etc.

[0043] In some embodiments, the pressure of the pressure pump 4 is adjustable, and the air pressure of the pressure pump 4 can be adjusted according to the air pressure loss of the air circuit, so as to generate a stable liquid detection air pressure in the pipette tip 1. For example, when the air circuit pressure loss is large, the gas pressure can be appropriately increased to make the air pressure in the pipette tip 1 more consistent, thereby improving the accuracy of liquid detection.

[0044] In some embodiments, Figure 2 and Figure 3 As shown, the pressure air pump 4 and the pipette tip 1 are connected through a first pipeline 6, and the piston air pump 4 and the pipette tip 1 are connected through a second pipeline 7, and the first pipeline 6 and the second pipeline 7 are independent. The position of the air pressure sensor 3 is not limited. Figure 2 In the illustrated embodiment, the air pressure sensor 3 is connected to the first pipeline 6 for detecting the air pressure in the first pipeline 6 . Figure 3 In the illustrated embodiment, the air pressure sensor 3 is connected to the pipette tip 1 for detecting the air pressure in the pipette tip 1 .

[0045] In other embodiments, Figures 4 to 6 As shown, the liquid detection device of the liquid pipette gun also includes a third pipeline 8 connected to the liquid pipette tip 1, and the pressure air pump 4 and the piston air pump 2 are connected to the third pipeline 8 through the fourth pipeline 9 and the fifth pipeline 10 respectively. The setting position of the air pressure sensor 3 is not limited. Figure 4 In the illustrated embodiment, the air pressure sensor 3 is connected to the third pipeline 8 for detecting the air pressure in the third pipeline 8 . Figure 5 In the illustrated embodiment, the air pressure sensor 3 is connected to the fourth pipeline 9 for detecting the air pressure in the fourth pipeline 9 . Figure 6 In the illustrated embodiment, the air pressure sensor 3 is connected to the pipette tip 1 for detecting the air pressure in the pipette tip 1 .

[0046] When the pipette tip 1 moves down to contact with the liquid, the air pressure in the pipette tip 1 will jump. The air pressure sensor 3 can detect the jump signal, and then determine whether the pipette tip 1 is in contact with the liquid, thereby realizing liquid detection.

[0047] The pressure air pump 4 is connected to the pipette tip 1, generating an airflow which enters the interior of the pipette tip 1 through the inlet end 101 of the pipette tip 1; in some cases, there are bubbles on the surface of the liquid, and when the pipette tip 1 contacts the bubbles in the liquid, the generated airflow is discharged through the outlet end 102 of the pipette tip 1 to push the bubbles away, thereby preliminarily solving the problem of the bubbles in the liquid contacting the pipette tip 1, causing a jump in the air pressure value.

[0048] In some embodiments, the pipette tip 1 is made of a conductive material, and the pipette tip 1 is connected to a capacitive sensor 11 for collecting the capacitance value of the pipette tip 1, such as a capacitive sensor 11 of model FDC2212, which is a high-resolution, multi-channel, capacitance-to-digital converter. The pipette tip 1 has a conductive property. According to the air pressure value and the capacitance value, the height detection of the liquid reagent level, the detection of whether there are bubbles, and the detection of whether the pipette tip 1 is blocked can be completed.

[0049] The controller 5 can be, for example, a single chip microcomputer or a PLC. The control system of the liquid detection device of the liquid pipette gun is a control system with single chip microcomputer or PLC calculation and logic control as the core. The controller 5 is electrically connected to the piston air pump 2, the pressure air pump 4, the air pressure sensor 3 and the capacitance sensor 11 respectively. The controller 5 is used to control the piston air pump 2 and the pressure air pump 4 to operate according to the detection signals of the air pressure sensor 3 and the capacitance sensor 11.

[0050] The air pressure value of the pipette tip 1 is collected in real time through the air pressure sensor 3, and the controller 5 receives the air pressure value collected by the air pressure sensor 3 and monitors it. When the air pressure value jumps, it means that the pipette tip 1 is in contact with the liquid or with bubbles. When the piston air pump 2 and the pressure air pump 4 are turned on and the pipette tip 1 is not in contact with the liquid and there is still an air pressure value, it means that the pipette tip 1 is blocked.

[0051] like Figures 2 to 6 As shown, the capacitive sensor 4 is electrically connected to the pipette tip 1 and the controller 5, and can collect the capacitance value of the pipette tip 1 in real time. The controller 5 detects the height of the liquid based on the capacitance value and the air pressure value; when the air pressure value jumps and the capacitance value changes, it indicates that the pipette tip 1 is in contact with the liquid, and the controller 5 calculates the height of the liquid according to the existing method; when the air pressure value jumps and the capacitance value remains unchanged, it indicates that the pipette tip 1 is in contact with the bubbles in the liquid, which effectively eliminates the liquid height obtained when the bubbles in the liquid are in contact with the pipette tip 1, thereby improving the accuracy of liquid detection.

[0052] Further, such as Figures 2 to 6 As shown, the liquid detection device of the liquid pipette gun also includes a driving device 12 electrically connected to the controller 5, and the driving device 12 is connected to the liquid pipette head 1, and is used to drive the liquid pipette tip 1 to perform lifting movement according to the instruction of the controller 5. Preferably, the driving device 12 can be a servo slide, an industrial robot, an electric push rod, an electric cylinder, etc.

[0053] When the above-mentioned pipette tip 1 contacts the bubble in the liquid, a shift instruction is sent through the controller 5 to control the driving device 12 to drive the pipette tip 1 to move downward, so that the conductive pipette tip 1 is inserted into the bubble to puncture the bubble, further solving the problem of the conductive reagent tube 1 contacting the bubble on the reagent liquid surface, causing a jump in the air pressure value, reducing the liquid detection error and improving the accuracy of liquid detection.

[0054] Among them, the outlet end 102 of the pipette tip 1 is conical. When the outlet end 102 of the pipette tip 1 contacts the bubbles in the liquid, the tip diameter is small, which makes it easier to puncture the bubbles. The contact area between the pipette tip 1 and the liquid is small, making it easier for the pipette tip 1 to achieve sealing, thereby improving the sensitivity of liquid detection.

[0055] 1. Detection of liquid height:

[0056] S11, the controller 5 drives the pipette tip 1 to move toward the liquid;

[0057] S12, generating gas pressure in the pipette tip 1 through the pressure air pump 4;

[0058] S13, detecting the air pressure in the air path through the air pressure sensor 3;

[0059] S14, the controller 5 obtains the detection signal of the air pressure sensor 3. If the air pressure value changes suddenly, it indicates that the pipette tip 1 is in contact with the liquid. Then the controller 5 calculates the height of the test liquid.

[0060] 2. Detection of liquid bubbles:

[0061] S21, the controller 5 drives the pipette tip 1 to move toward the liquid;

[0062] S22, generating gas pressure in the pipette tip 1 through the pressure air pump 4;

[0063] S23, detecting the air pressure in the air circuit through the air pressure sensor 3, and detecting the capacitance in the pipette tip 1 through the capacitance sensor 11;

[0064] S24, the controller 5 obtains detection signals from the air pressure sensor 3 and the capacitance sensor 11. If the air pressure value changes suddenly and the capacitance value remains unchanged, it indicates that the pipette tip 1 is in contact with bubbles in the liquid;

[0065] S24, the controller 5 sends a shift instruction to control the driving device 12 to drive the pipette tip 1 to move downward, so that the pipette tip 1 is inserted into the bubble to puncture the bubble.

[0066] 3. Detection of pipe blockage:

[0067] S31, making the pipette tip 1 out of contact with the liquid;

[0068] S32, generating air pressure in the pipette tip 1 by the piston air pump 2 and / or the pressure air pump 4;

[0069] S33, detecting the air pressure value in the air path through the air pressure sensor 3;

[0070] S34. If the air pressure value is greater than the preset value, it is determined that the pipette tip 1 is clogged.

[0071] The preset value can be selected according to actual working conditions or experience, for example, a normal air pressure value greater than a certain range is selected, and the normal air pressure value is the air pressure value in the air path when the pipette tip 1 is not blocked.

[0072] The above are only specific implementations of the present invention, and any improvements made based on the concept of the present invention are considered to be within the protection scope of the present invention.

Claims

1. A liquid detection device for a liquid transfer gun, characterized in that: include: A pipette tip, comprising an inlet end and an outlet end arranged opposite to each other, wherein the outlet end is used for contacting the liquid; A piston air pump, connected to the pipette tip, for generating air pressure to draw the liquid into or out of the pipette tip; A pressure air pump, connected to the pipette tip, for generating a gas pressure of adjustable duration in the pipette tip; An air pressure sensor connected to the air circuit formed by the pipette tip and the pressure air pump, and used for detecting the air pressure in the air circuit; as well as, The controller is electrically connected to the air pressure sensor and is used to determine whether the pipette tip is in contact with the liquid based on the detection signal of the air pressure sensor. If the air pressure value changes suddenly, it indicates that the pipette tip (1) is in contact with the liquid. The height of the test liquid is then calculated by the controller (5).

2. The liquid detection device for a liquid transfer gun according to claim 1, characterized in that: The pressure air pump is connected to the pipette tip via a first pipeline, and the piston air pump is connected to the pipette tip via a second pipeline; The air pressure sensor is connected to the first pipeline and is used to detect the air pressure in the first pipeline; or, The air pressure sensor is connected to the pipette tip and is used to detect the air pressure in the pipette tip.

3. The liquid detection device for a liquid transfer gun according to claim 1, characterized in that: It also includes a third pipeline connected to the pipette tip, and the pressure air pump and the piston air pump are connected to the third pipeline through a fourth pipeline and a fifth pipeline respectively; The air pressure sensor is connected to the third pipeline and is used to detect the air pressure in the third pipeline; or, The air pressure sensor is connected to the fourth pipeline and is used to detect the air pressure in the fourth pipeline; or, The air pressure sensor is connected to the pipette tip and is used to detect the air pressure in the pipette tip.

4. The liquid detection device for a liquid transfer gun according to claim 1, characterized in that: The pipette tip is made of conductive material, and is connected to a capacitance sensor for collecting the capacitance value of the pipette tip.

5. The liquid detection device for a liquid transfer gun according to claim 4, characterized in that: The controller is electrically connected to the piston air pump, the pressure air pump, the air pressure sensor and the capacitive sensor. The controller is a single chip microcomputer or a PLC, and is used to control the operation of the piston air pump and the pressure air pump according to the detection signals of the air pressure sensor and the capacitive sensor.

6. The liquid detection device for a liquid transfer gun according to claim 4, characterized in that: If the air pressure value detected by the air pressure sensor jumps and the capacitance value detected by the capacitance sensor changes, it indicates that the pipette tip is in contact with the liquid; if the air pressure value jumps and the capacitance value remains unchanged, it indicates that the pipette tip is in contact with the bubbles in the liquid.

7. The liquid detection device for a liquid transfer gun according to any one of claims 1 to 6, characterized in that: It also includes a driving device electrically connected to the controller, the driving device is connected to the pipette head, and is used to drive the pipette head to perform lifting movement according to the instructions of the controller.

8. The liquid detection device for a liquid transfer gun according to any one of claims 1 to 6, characterized in that: The outlet end of the pipette tip is conical.

9. The liquid detection device for a liquid transfer gun according to any one of claims 1 to 6, characterized in that: The gas pressure generated by the pressure air pump is adjustable.

10. The liquid detection device for a liquid transfer gun according to any one of claims 1 to 6, characterized in that: The pressure air pump is an impeller pump.

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