Self-priming volumetric pipet

Abstract

The application provides a self-suction constant-volume pipetting glass device, which comprises a pipette main body arranged vertically, an air extraction assembly, a commutating valve assembly and a liquid discharge pipe arranged vertically; the air extraction assembly is located above the pipette main body; the commutating valve assembly has a first channel and a second channel which are independent of each other; the commutating valve assembly has a first state and a second state; in the first state, the first channel is in communication with the top opening of the pipette main body and the air extraction assembly respectively; in the second state, the second channel is in communication with the air extraction assembly and the liquid discharge pipe respectively, and the two ends of the first channel are blocked. The self-suction constant-volume pipetting glass device provided by the application realizes the absorption of liquid through the communication of the pipette main body, the commutating valve assembly and the air extraction assembly, discharges the overflow liquid through the liquid discharge pipe, and keeps the liquid of a preset volume in the pipette main body, thereby realizing constant-volume pipetting.

Description

Technical Field

[0001] This invention belongs to the field of quantitative pipette technology, specifically relating to a self-priming, volumetric pipetting glass device. Background Technology

[0002] A pipette is a glass instrument used to accurately measure a quantitative amount of solution. It is a very important chemical glass instrument, crucial for measuring liquid volume, and quantitative pipetting is the most common experimental procedure in all physics, chemistry, and biology laboratories.

[0003] Most existing quantitative pipettes directly draw the required amount of liquid into the pipette before proceeding to the next experimental step. Currently used pipettes typically draw liquid by pulling the stopcock. While manually pulling the stopcock, the operator observes the scale on the pipette to determine if the liquid drawn is the correct amount. This judgment is greatly affected by the operator's eye position and individual judgment, making it prone to errors. The stopcock may not stop perfectly, leading to deviations in the manually drawn amount of liquid, resulting in inaccurate liquid volume and inaccurate experimental results. Furthermore, quantitative liquid drawing requires repeated observation and adjustment by the operator, necessitating multiple adjustments to obtain the correct amount of liquid, making the operation difficult. Summary of the Invention

[0004] This invention provides a self-priming, volumetric liquid transfer glass device, which aims to solve the technical problems in the prior art where the volumetric liquid transfer is greatly affected by the operator's personal judgment, easily leading to deviations and making the operation of aspirating a fixed amount of liquid difficult.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a self-priming volumetric pipetting glass device, comprising:

[0006] The main body of the vertically arranged pipette;

[0007] An air extraction assembly is located above the main body of the pipette;

[0008] Vertically installed drain pipes; and

[0009] The converter valve assembly has an independent first channel and a second channel inside;

[0010] The converter valve assembly has a first state and a second state;

[0011] The first state is that the first channel is connected to the top opening of the pipette body and the air extraction assembly respectively, and one end of the second channel is blocked, while the other end is connected to the drain pipe;

[0012] The second state is a state in which the second channel is connected to the air extraction component and the drain pipe respectively, and the two ends of the first channel are blocked, and the top opening of the pipette body is blocked.

[0013] In one possible implementation, the air extraction assembly includes:

[0014] An air extraction connector is connected to the converter valve assembly;

[0015] An air extraction pipe is connected to the air extraction connector, and an air extraction port is formed at the bottom of the air extraction pipe.

[0016] A three-way valve is provided on the suction pipe; and

[0017] A vacuum pump is located at the top opening of the extraction pipe, and the vacuum pump is connected to the extraction pipe.

[0018] In one possible implementation, an anti-retraction space is formed inside the suction pipe, and a space opening is formed at the lower part of the anti-retraction space. The suction connector is sealed and inserted into the space opening. The upper port of the suction connector is higher than the space opening, and the extension end of the suction connector is spaced horizontally from the inner wall of the anti-retraction space.

[0019] In one possible implementation, a sealing sleeve is provided at the connection between the air extraction connector and the air extraction pipe.

[0020] In one possible implementation, the converter valve assembly includes:

[0021] A housing having a single-sided opening for a flow exchange chamber, with a lower inlet, an upper inlet, and a side outlet formed on the housing corresponding to the flow exchange chamber. The upper inlet communicates with the air inlet end of the suction assembly; the lower inlet communicates with the main body of the pipette; and the side outlet communicates with the drain pipe.

[0022] A converter valve is slidably inserted into the converter cavity in the horizontal direction, and the converter valve forms the first channel and the second channel;

[0023] When the converter valve is in the first state, the two ends of the first channel are connected to the lower inlet and the upper inlet, respectively, and one end of the second channel is connected to the side outlet, while the other end is blocked by the housing.

[0024] When the converter valve is in the second state, the two ends of the second channel are connected to the upper inlet and the side outlet, respectively, and the two ends of the first channel are blocked by the housing.

[0025] In one possible implementation, a horizontally extending receiving pipe is formed on the side of the drain pipe, the receiving pipe extends into the exchange chamber through the side opening, and the cross-sectional area of ​​the receiving pipe gradually decreases in the direction toward the housing.

[0026] The second channel is provided with a second conduit, one end of which forms a drain end extending in a horizontal direction, and the drain end is inserted into and connected to the receiving pipe.

[0027] In one possible implementation, the switching valve has a handle on the side opposite to the side opening.

[0028] In one possible implementation, a spherical cavity is formed at the top of the pipette body.

[0029] In one possible implementation, there are multiple pipette bodies, each with a different volume of the spherical cavity. The multiple pipette bodies are connected sequentially in the vertical direction, and the volumes of the multiple spherical cavities decrease sequentially from top to bottom.

[0030] A flow-changing valve assembly is provided between the adjacent spherical cavity and the bottom opening of the pipette body, and the flow-changing valve assembly is connected to the top opening of the corresponding spherical cavity and the receiving tube, respectively.

[0031] In one possible implementation, a liquid collecting device is connected to the bottom of the drain pipe for collecting the liquid discharged from the drain pipe.

[0032] The self-priming, constant-volume pipetting glass device provided by this invention, compared with the prior art, has a pipette body with a preset volume of liquid to be moved. The pipette body is connected to an air extraction assembly via a flow-changing valve assembly to achieve liquid aspiration. When the pipette body is full of water, air extraction continues until the liquid enters the air extraction assembly. The flow-changing valve assembly then connects the air extraction assembly to the drain pipe, and the liquid flowing into the air extraction assembly is discharged from the drain pipe, leaving the preset volume of liquid in the pipette body. This process eliminates the need for manual observation of the scale to determine whether the preset volume of liquid has been aspirated, avoiding errors caused by manual judgment, reducing labor intensity, simplifying operation steps, and lowering operational difficulty. This application only requires continuous liquid aspiration, with excess liquid flowing out through the drain pipe. A single operation can extract the preset volume of liquid, improving pipetting accuracy, reducing aspiration difficulty, and accelerating the overall experimental process. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of the self-priming volume-regulating glass pipetting device provided in Embodiment 1 of the present invention;

[0035] Figure 2 This is a cross-sectional view of the self-priming, volumetric pipetting glass device provided in Embodiment 1 of the present invention;

[0036] Figure 3 This is a schematic diagram illustrating another usage state of the housing and the switching valve in Embodiment 1 of the present invention;

[0037] Figure 4 This is a cross-sectional view of the drain pipe used in Embodiment 1 of the present invention;

[0038] Figure 5 This is a schematic diagram of the shell structure used in Embodiment 1 of the present invention;

[0039] Figure 6 This is a schematic diagram of the flow-changing valve used in Embodiment 1 of the present invention;

[0040] Figure 7 This is a schematic diagram of the air extraction assembly used in Embodiment 1 of the present invention;

[0041] Figure 8 This is a schematic diagram of the structure of the self-priming volume-regulating glass pipetting device provided in Embodiment 2 of the present invention.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Pipette body; 12. Spherical cavity;

[0044] 2. Vacuum assembly; 21. Vacuum connector; 22. Vacuum pipe; 221. Anti-retraction space; 222. Vacuum port; 23. Three-way valve; 24. Vacuum pump; 25. Sealing sleeve;

[0045] 3. Converter valve assembly;

[0046] 31. Housing; 310. Converter cavity; 311. Lower inlet; 312. Upper inlet; 313. Side outlet;

[0047] 32. Flow converter valve; 321. First channel; 322. Second channel; 323. Insertion slot;

[0048] 33. First catheter;

[0049] 34. Second catheter;

[0050] 35. Handle;

[0051] 4. Drain pipe; 41. Drain port; 42. Liquid receiving pipe;

[0052] 5. Liquid collection components. Detailed Implementation

[0053] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0054] It should be noted that the terms "length", "width", "height", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", and "tail" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0055] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0056] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Additionally, "multiple" and "several" mean two or more, unless otherwise explicitly specified.

[0057] Please refer to the following: Figures 1 to 8The self-priming volume-fixing pipetting apparatus provided by the present invention will now be described. The self-priming volume-fixing pipetting apparatus includes a vertically arranged pipette body 1, an air extraction assembly 2, a flow exchange valve assembly 3, and a vertically arranged drain pipe 4. The air extraction assembly 2 is located above the pipette body 1; the flow exchange valve assembly 3 has an independent first channel 321 and a second channel 322; the flow exchange valve assembly 3 has a first state and a second state; the first state is that the first channel 321 is connected to the top opening of the pipette body 1 and the air extraction assembly 2 respectively, and one end of the second channel 322 is blocked, while the other end is connected to the drain pipe 4; the second state is that the second channel 322 is connected to the air extraction assembly 2 and the drain pipe 4 respectively, and both ends of the first channel 321 are blocked, and the top opening of the pipette body 1 is blocked.

[0058] It should be noted that the long axis of the drain pipe 4 is set parallel to the long axis of the pipette body 1.

[0059] It should be noted that the converter valve assembly 3 has a liquid suction state that connects the pipette body 1 and the vacuum assembly 2, at which time the drain pipe 4 is blocked; it also has a liquid discharge state that connects the vacuum assembly 2 and the drain pipe 4, at which time the pipette body 1 is blocked, and the quantitative liquid in the pipette body 1 is the preset liquid volume to be taken.

[0060] The self-priming volumetric pipetting device of this embodiment does not require manual judgment of the volume of liquid being drawn. The liquid is drawn into the vacuum assembly 2 in one go, and the vacuum assembly 2 and the drain pipe 4 are connected by the flow exchange valve assembly 3. The excess liquid is discharged through the drain pipe 4. The remaining liquid in the self-priming volumetric pipetting device is the pre-quantitative liquid.

[0061] The self-priming, constant-volume pipetting apparatus provided in this embodiment, compared with the prior art, has a pipette body 1 with a volume of a preset liquid volume. The pipette body 1 is connected to the vacuum assembly 2 via a flow-changing valve assembly 3 to aspirate liquid. Once the pipette body 1 is full of liquid, vacuuming continues until the liquid enters the vacuum assembly 2. The flow-changing valve assembly then connects the vacuum assembly 2 to the drain pipe 4, allowing the liquid flowing into the vacuum assembly 2 to drain out through the drain pipe 4, leaving the preset volume of liquid in the pipette body 1. This process eliminates the need for manual observation of the scale to determine whether the preset volume of liquid has been aspirated, avoiding errors caused by manual judgment, reducing labor intensity, simplifying operation steps, and lowering operational difficulty. This application only requires continuous aspiration of liquid, with excess liquid flowing out through the drain pipe 4. A single operation can extract the preset volume of liquid, improving pipetting accuracy, reducing aspiration difficulty, and accelerating the overall experimental process.

[0062] In some embodiments, see Figure 7 and Figure 2The air extraction assembly 2 includes an air extraction connector 21, an air extraction pipe 22, a three-way valve 23, and a vacuum pump 24. The air extraction connector 21 is connected to the converter valve assembly 3; the air extraction pipe 22 is connected to the air extraction connector 21, and an air extraction port 222 is formed at the bottom of the air extraction pipe 22; the three-way valve 23 is located on the air extraction pipe 22; the vacuum pump 24 is located at the top opening of the air extraction pipe 22, and the vacuum pump 24 is connected to the air extraction pipe 22.

[0063] In practice, the suction connector 21 is fixed to the converter valve assembly 3, with one end connected to the converter valve assembly 3 and the other end connected to the suction pipe 22. The three-way valve 23 controls whether the suction pipe 22 is connected to the outside air. When the suction pipe 22 is isolated from the outside, and the vacuum pump 24 is pumping air, the internal pressure of the suction pipe 22 is lower than the external pressure, thus achieving liquid extraction. When the three-way valve 23 is operated to connect the suction pipe 22 to the outside, the liquid drawn into the pipette body 1 can fall. The cooperation of the three-way valve 23 and the vacuum valve 24 realizes the extraction and release of liquid.

[0064] It should be noted that the vacuum pump 24 is a miniature vacuum pump with a very small mass, so it will not cause any burden to the operator's hands.

[0065] The vacuum pump 2 provided in this embodiment has a simple composition. The vacuum pump 24 is connected to the pipette body 1 through the vacuum pipe 22 and the vacuum connector 21. The vacuum pump 24 can quickly draw up liquid in one go, eliminating the need for repeated manual extraction by the staff, thus reducing labor intensity. The vacuum pump 24 can continuously provide suction, realizing automated liquid extraction, accelerating extraction efficiency, and reducing extraction difficulty.

[0066] In some embodiments, see Figure 2 and Figure 7 An anti-retraction space 221 is formed inside the suction pipe 22, and an opening is formed at the bottom of the anti-retraction space 221. The suction connector 21 is sealed and inserted into the opening. The upper end of the suction connector 21 is higher than the opening, and the insertion end of the suction connector 21 is horizontally spaced from the inner wall of the anti-retraction space. To prevent the vacuum pump 24 from drawing in too much liquid and causing it to come into contact with the vacuum pump 22, the anti-retraction space 221 has a large volume and can buffer the liquid. Liquid entering the suction pipe 22 will flow into the anti-retraction space 221, preventing the vacuum pump 24 from being damaged by contact with the liquid.

[0067] In some embodiments, see Figure 7 A sealing sleeve 25 is fitted at the connection between the air extraction connector 21 and the air extraction pipe 22. The sealing sleeve 25 fits tightly with the air extraction connector 24 and the air extraction pipe 22 respectively, ensuring the sealing of the connection between the air extraction connector 21 and the air extraction pipe 22, ensuring the sealing of the inside of the air extraction pipe 22, and thus ensuring the normal operation of the air extraction.

[0068] In some embodiments, see Figure 3 , Figure 5 and Figure 6 The converter valve assembly 3 includes a housing 31 and a converter valve 32. The housing 31 has a single-sided opening for a flow exchange chamber 310. A lower inlet 311, an upper inlet 312, and a side outlet 313 are formed on the housing 31 corresponding to the flow exchange chamber 310. The upper inlet 312 is connected to the air inlet end of the suction assembly 2. The lower inlet 311 is connected to the pipette body 1, and the side outlet 313 is connected to the drain pipe 4. A flow exchange valve 32 is slidably inserted into the flow exchange chamber 310 in a horizontal direction. A first channel 321 and a second channel 322 are formed within the flow exchange valve 32. When the flow exchange valve 32 is in the first state, both ends of the first channel 321 are connected to the lower inlet 311 and the upper inlet 312, respectively. One end of the second channel 322 is connected to the side outlet 313, and the other end is blocked by the housing 31. When the flow exchange valve 32 is in the second state, both ends of the second channel 322 are connected to the upper inlet 312 and the side outlet 313, respectively, and both ends of the first channel 321 are blocked by the housing 31.

[0069] It should be noted that the lower inlet 311 is connected to the pipette body 1, and the upper inlet 312 is connected to the air extraction connector 21. During installation, the pipette body 1 is inserted into the lower inlet 311, and the air extraction connector 31 is inserted into the upper inlet 312 and fixed.

[0070] It should be understood that the side opening 313 is opposite to the opening side, and the converter valve 32 slides against the inner wall of the converter cavity 310 in the direction that is close to or away from the side opening 313.

[0071] As one specific embodiment of the housing 31, the housing 31 is a transparent housing, which makes it convenient for staff to observe whether the inside of the housing 31 is working properly.

[0072] The converter valve assembly 3 provided in this embodiment has two working states. In the first state, only the first channel 321 and the upper inlet 312 are connected. In the second state, only the second channel 322 is connected to the upper inlet 312. Liquid can only be moved from the pipette body 1 through the first channel 321 to the suction pipe 22, or from the suction pipe 22 along the second channel 322 to the drain pipe 4. The two working states do not interfere with each other, ensuring that when the liquid in the suction pipe 22 is discharged, the liquid in the pipette body 1 will not fall, thereby ensuring that the remaining liquid is the pre-selected quantitative solution and ensuring the pipetting accuracy.

[0073] In some embodiments, see Figure 3 and Figure 4The drain pipe 4 has a horizontally extending receiving pipe 42 on its side. The receiving pipe 42 passes through the side opening 313 and extends into the exchange chamber 310. The cross-sectional area of ​​the receiving pipe 42 gradually decreases in the direction toward the housing 31. The second channel 322 is provided with a second conduit 34. One end of the second conduit 34 forms a drain end that extends horizontally and is connected to the receiving pipe 42.

[0074] It should be noted that regardless of whether the exchange valve assembly 32 is in the second state or the first state, the liquid receiving pipe 42 is always connected to the second conduit 34.

[0075] The liquid receiving tube 42 provided in this embodiment can pass through the side opening 313 and connect to the second conduit 34, ensuring that when the second conduit 34 and the suction tube 22 are connected, the liquid can flow from the suction tube 22 through the second conduit 34 to the drain tube 4. The liquid receiving chamber 421 can guide the liquid into the drain tube, avoiding the situation where liquid remains in the second conduit.

[0076] In specific implementation, a first conduit 33 is provided in the first channel 321, and the length of the first conduit 33 is the same as the length of the first channel 321.

[0077] In some embodiments, the side of the flow exchange valve 32 corresponding to the opening 313 is provided with a insertion groove 323, the outer wall of the liquid receiving pipe 42 is inserted into the insertion groove 323, and the second conduit 34 is connected to the interior of the liquid receiving pipe 42.

[0078] In some embodiments, see Figure 3 A handle 35 is provided on the side of the converter valve 32 opposite to the side opening. The handle 35 is convenient for the operator to hold in order to pull out or push in the converter valve 32 from the housing 31.

[0079] In some embodiments, see Figure 1 and Figure 2 A spherical cavity 11 is formed at the top of the pipette body 1. The spherical cavity 11 can increase the liquid holding volume of the pipette body 1 without increasing the volume by lengthening the pipette body 1, thereby reducing the length of the pipette body 1, reducing manufacturing costs, and facilitating the storage and movement of the pipette body 1.

[0080] It should be noted that the effective volume of the pipette body 1 is the volume of the pipette body 1 plus the volume of the spherical cavity 11 and the volume of the corresponding first catheter 33.

[0081] In some embodiments, see Figure 8The pipette body 1 is provided in multiple ways. The volume of the spherical cavity 11 of each pipette body 1 is different. The multiple pipette bodies 1 are connected in sequence along the vertical direction, and the volume of the multiple spherical cavities 11 decreases in sequence from top to bottom. A flow exchange valve assembly 3 is provided between the top opening of the adjacent spherical cavity 11 and the bottom opening of the pipette body 1. The flow exchange valve assembly 3 is connected to the top opening and the liquid receiving port of the corresponding pipette body 1, respectively.

[0082] It should be noted that the centers of the multiple spherical cavities 11 are arranged collinearly.

[0083] In practice, the multiple spherical cavities 11 represent different volumes. The main body of the pipette 1 has three spherical cavities 11, which represent 10ml, 25ml, and 50ml respectively.

[0084] The 10ml volume means that the volume of the spherical cavity 11 plus the corresponding pipette body 1 plus the liquid volume in the corresponding first conduit 33 is 10ml.

[0085] The 25ml volume means that the volume of the spherical cavity 11 plus the corresponding pipette body 1 plus the liquid volume in the corresponding first conduit 33 is 25ml.

[0086] The 50ml volume means that the volume of the spherical cavity 11 plus the corresponding pipette body 1 plus the liquid volume in the corresponding first conduit 33 is 50ml.

[0087] When 35ml of liquid needs to be transferred, air is drawn out by vacuum pump 24, and the liquid is drawn into the pipette body. When the liquid is drawn into the uppermost pipette body 1, vacuum pump 24 is turned off, the uppermost flow exchange valve assembly 3 is turned on, and the flow exchange valve assembly 3 is changed to the second state. The liquid in the uppermost pipette body 1 is discharged, and the total volume of liquid remaining in the entire device is 35ml.

[0088] As a specific embodiment of this example, a self-priming volumetric pipetting glass device can be assembled as needed. For example, when quantitatively transferring 100ml of liquid, two 50ml spherical cavities 11 or one 50ml spherical cavity 11 plus two 25ml spherical cavities 11 can be selected.

[0089] In some embodiments, see Figure 8 A liquid collecting device 5 is connected to the bottom of the drain pipe 4. The liquid collecting device 5 is used to collect the liquid discharged from the drain pipe 4. The liquid collecting device 5 can recover excess liquid, improve the liquid recovery rate, and thus save costs.

[0090] The following is a specific embodiment of a self-priming, constant-volume pipetting glass device:

[0091] Take a 50ml volume of liquid and select a 50ml spherical cavity 11;

[0092] Immerse the bottom opening of the pipette body 1 into the liquid, and push the flow exchange valve 32 through the handle 35 to connect the first conduit 33 to the pipette body 1 and the suction tube 22 respectively;

[0093] After adjusting the three-way valve 23, the vacuum pump 24 is turned on, and the liquid is drawn into the pipette body 1.

[0094] Continue to turn on the vacuum pump 24 until liquid enters the suction pipe 22, then turn off the vacuum pump 24.

[0095] Pull out the converter valve 32 by the handle 35 to connect the second conduit 34 and the suction pipe 22. Open the three-way valve 23 to connect the suction pipe 22 with the outside. The liquid in the suction pipe 22 flows into the drain pipe 4 along the second conduit 34 and is collected in the liquid collection device 5 along the drain pipe 4.

[0096] Move the self-priming volumetric pipetting glass device to the container where the liquid needs to be added, push the handle 35 to reconnect the first conduit 33 with the pipetting tube body 1 and the suction tube 22, and the liquid in the first conduit 33, the tube body of the pipetting tube body 1, and the spherical cavity 11 flows down to complete the quantitative pipetting operation.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-priming, volumetric pipetting glass device, characterized in that, include: The main body of the vertically arranged pipette; An air extraction assembly is located above the main body of the pipette; Vertically installed drain pipe; as well as The converter valve assembly has an independent first channel and a second channel inside; The converter valve assembly has a first state and a second state; The first state is that the first channel is connected to the top opening of the pipette body and the air extraction assembly respectively, and one end of the second channel is blocked, while the other end is connected to the drain pipe; The second state is a state in which the second channel is connected to the air extraction component and the drain pipe respectively, and the two ends of the first channel are blocked, and the top opening of the pipette body is blocked; The air extraction assembly includes: An air extraction connector is connected to the converter valve assembly; An air extraction pipe is connected to the air extraction connector, and an air extraction port is formed at the bottom of the air extraction pipe. A three-way valve is provided on the suction pipe; and A vacuum pump is located at the top opening of the suction pipe, and the vacuum pump is connected to the suction pipe; The converter valve assembly includes: A housing having a flow exchange chamber open on one side, with a lower inlet, an upper inlet, and a side opening formed on the housing corresponding to the flow exchange chamber. The upper inlet communicates with the air inlet end of the suction assembly; the lower inlet communicates with the main body of the pipette; and the side opening communicates with the drain pipe. A converter valve is slidably inserted into the converter cavity through the opening in a horizontal direction, and the converter valve forms the first channel and the second channel; When the converter valve is in the first state, the two ends of the first channel are connected to the lower inlet and the upper inlet, respectively, and one end of the second channel is connected to the side opening, while the other end is blocked by the housing. When the converter valve is in the second state, the two ends of the second channel are connected to the upper inlet and the side opening, respectively, and the two ends of the first channel are blocked by the housing.

2. The self-priming, constant-volume pipetting glass apparatus as described in claim 1, characterized in that, An anti-retraction space is formed inside the air extraction pipe, and a space opening is formed at the lower part of the anti-retraction space. The air extraction connector is sealed and inserted into the space opening. The upper port of the air extraction connector is higher than the space opening, and the extension end of the air extraction connector is spaced apart from the inner wall of the anti-retraction space in the horizontal direction.

3. The self-priming, constant-volume pipetting glass apparatus as described in claim 1, characterized in that, A sealing sleeve is fitted at the connection between the air extraction connector and the air extraction pipe.

4. The self-priming, constant-volume pipetting glass apparatus as described in claim 1, characterized in that, The drain pipe has a horizontally extending receiving pipe on its side. The receiving pipe passes through the side opening and extends into the exchange chamber. The cross-sectional area of ​​the receiving pipe gradually decreases in the direction toward the housing. The second channel is provided with a second conduit, one end of which forms a drain end extending horizontally. The drain end is inserted into and connected to the receiving pipe.

5. The self-priming, constant-volume pipetting glass apparatus as described in claim 1, characterized in that, The converter valve has a handle on the side opposite to the side opening.

6. The self-priming volumetric pipetting glass apparatus as described in claim 4, characterized in that, A spherical cavity is formed at the top of the pipette body.

7. The self-priming volumetric pipetting glass apparatus as described in claim 6, characterized in that, The pipette body is provided in multiple parts, and the volume of the spherical cavity of each pipette body is different. The multiple pipette bodies are connected sequentially in the vertical direction, and the volume of the multiple spherical cavities decreases sequentially from top to bottom. Each of the spherical cavities is provided with a flow-changing valve assembly at its top opening. The bottom opening of the upper spherical cavity is connected to the top opening of the lower pipette body. The flow-changing valve assembly is connected to the top opening of the corresponding spherical cavity and the receiving pipe, respectively.

8. The self-priming, constant-volume pipetting glass apparatus as described in claim 1, characterized in that, The bottom of the drain pipe is connected to a liquid collecting device, which is used to collect the liquid discharged from the drain pipe.

Images