Piston core pin and air displacement pipette including same

Abstract

A piston core pin capable of dispensing a more accurate amount of liquid sample by reducing the volume of the air cushion under the piston and an air displacement pipette including the same are disclosed. The piston core includes a piston, a piston core pin, and a pusher rod. The piston is formed to contact the inside of a pipette housing and has a hole formed therein. The piston core pin is formed to have a rod shape with an extended cross section having the same shape as the hole of the piston, and a lower part is supported by the pipette and an air path through which air can pass is formed at the lower part. With such a piston core, the volume of the air cushion under the piston can be reduced to dispense a more accurate amount of liquid sample.

Description

[Technical field]

[0001] The present invention relates to a piston core and an air displacement pipette including the same, and more particularly to a piston core and an air displacement pipette including the same that can attenuate the air cushion volume between a piston and a sample to reduce the compressibility and improve the efficiency of quantitatively dispensing a sample. [Background technology]

[0002] Pipettes are widely used to aspirate and dispense liquid samples for chemical and biological testing. Such pipettes are syringe-shaped and use the piston action to aspirate and dispense liquid samples.

[0003] Such pipettes, which are used for precisely dispensing a fixed volume of a liquid sample, can be broadly classified into direct displacement type and air displacement type.

[0004] In the direct replacement method, the end of the piston in the pipette directly contacts the liquid sample while the piston moves up and down to aspirate and dispense the liquid sample, and there is no air cushion between the end of the piston and the liquid sample. This direct replacement method can aspirate and dispense a relatively precise volume of sample, and can repeatedly dispense the same amount of sample multiple times depending on the dispenser settings, but it can only be used for a single sample and must be disposed of to prevent cross-contamination. Therefore, in automatic dispensing medical devices for biological samples, where contamination is very important, there is a problem that a huge amount of waste is generated and costs are high because the entire pipette must be replaced and disposed.

[0005] In contrast, the air displacement method uses the difference in volume created by the air cushion caused by the up and down movement of the piston inside the pipette to aspirate the sample once and then dispense it at multiple points. In other words, there is an air cushion between the end of the piston and the liquid sample, and there is no contact between the end of the piston and the liquid sample. When the piston is compressed or pulled, the liquid sample is discharged by the pressure caused by the change in volume of the internal air cushion.

[0006] This air displacement method allows the tip to be replaced with a new one after a single use to prevent cross-contamination when working with a different sample, making it suitable for automatic dispensing medical equipment, most of which use air displacement pipettes.

[0007] However, despite the advantages of the air replacement method, the air replacement method aspirates or dispenses a liquid sample using the pressure of an internal air cushion, and is therefore significantly disadvantageous compared to the direct replacement method in terms of dispensing or aspirating a precise amount.

[0008] That is, when the piston is pulled to aspirate a liquid sample, the liquid is sucked in after a certain time has passed, and when the piston is pushed to eject a liquid sample, the liquid sample is ejected after a certain time has passed, making it difficult to dispense a precise amount. Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, the problem that the present invention aims to solve is to provide a piston core that can enable a pipette to dispense more accurate amounts.

[0010] Another problem that the present invention aims to solve is to provide a pipette having such a piston core. [Means for solving the problem]

[0011] A piston core according to an exemplary embodiment of the present invention includes a piston, a piston core pin, and a pusher rod. The piston is formed to contact the inner surface of a pipette housing and has a hole formed therein. The piston core pin is formed to have a rod shape with an extended cross section having the same shape as the hole of the piston, a lower part of which is supported by the pipette, and an air path through which air can pass is formed at the lower part. The pusher rod moves the piston inside the pipette housing.

[0012] In one embodiment, the piston and the hole may be circular in plan view, and the hole may be formed in the center of the piston.

[0013] In one embodiment, the pusher rod may be formed in a plurality of pieces along the outer side of the piston.

[0014] As an example, the pusher rod may be cylindrical and connected to the piston such that the hole is disposed inside the pusher rod.

[0015] As an example, the side surface of the piston may have a shape in which the center portion protrudes.

[0016] As an example, a side groove may be formed in the center of the side surface of the piston.

[0017] As an example, O-rings may be attached to the outer and inner surfaces of the piston.

[0018] As an example, the lower portion of the piston core pin may be formed to be inclined so as to be supported by a step of the pipette.

[0019] In one embodiment, the air path may be formed in a plurality of parts.

[0020] An air displacement pipette according to an exemplary embodiment of the present invention includes any one of the piston cores and a housing described above. The housing has the piston core disposed inside and a step portion formed at a lower portion thereof, so that the thickness of the housing is reduced.

[0021] As an example, such an air displacement pipette may further include a tip portion that is detachably fastened to the lower portion of the housing and that contacts the liquid sample. Effect of the Invention

[0022] As described above, the piston core according to the present invention allows for a more precise dispensing of a liquid sample by reducing the volume of the air cushion below the piston.

[0023] Moreover, the present invention can be easily attached to a conventional pipette without replacing the entire pipette, thereby improving the performance of a conventional biological sample dispensing device. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a cross-sectional view showing a typical air displacement pipette. [Diagram 2] FIG. 2 is a cross-sectional view showing an air displacement pipette equipped with a piston core according to an exemplary embodiment of the present invention. [Diagram 3] FIG. 3 is an exploded perspective view of the piston core shown in FIG. 2. [Figure 4] FIG. 4 is a bottom plan view of the piston core pin shown in FIG. 3. [Diagram 5] FIG. 4 is a side view showing another embodiment of the piston shown in FIG. 3. [Figure 6] FIG. 4 is a side view showing still another embodiment of the piston shown in FIG. 3. [Figure 7] FIG. 4 is a cross-sectional view showing still another embodiment of the piston shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Since the present invention can be modified in various ways and can have various forms, specific embodiments are illustrated in the drawings and described in detail in this specification. However, this does not limit the present invention to the specific embodiments, and it should be understood that the present invention includes all modifications, equivalents, or alternatives within the spirit and technical scope of the present invention. In the description of each drawing, similar components are represented by similar reference numerals. In the attached drawings, the dimensions of structures may be exaggerated to enhance the clarity of the present invention.

[0026] Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. These terms are used only to distinguish one component from another. For example, a first component may be named a second component, and similarly, a second component may be named a first component, without departing from the scope of the present invention.

[0027] The terms used in this application are used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "comprise" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. In addition, the meaning of "connected" or "coupled" between A and B includes the case where A and B are directly connected or coupled, as well as the case where another component C is included between A and B to connect or couple A and B.

[0028] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms as defined in commonly used dictionaries should be interpreted as meanings consistent with the meanings they have in the context of the relevant art, and should not be interpreted in an ideal or overly formal sense unless expressly defined in this application. In addition, in the scope of claims of method inventions, unless each step is expressly bound to a particular order, each step may be reordered.

[0029] Furthermore, the configurations described individually in each embodiment can also be applied to other embodiments.

[0030] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

[0031] FIG. 1 is a cross-sectional view showing a typical air displacement pipette.

[0032] Referring to Figure 1, a typical conventional air displacement pipette (1000) includes a housing (1100), a piston (1200), and a tip portion (1300).

[0033] When the piston (1200) is pulled, the pressure of the air cushion (AC) inside the housing (1100) decreases, and the liquid sample (LS) in contact with the tip unit (1300) flows into the tip unit (1300). Conversely, when the piston (1300) is pushed, the pressure of the air cushion (AC) inside the housing (1100) increases, and the liquid sample (LS) inside the tip unit (1300) flows out to the outside of the tip unit (1300).

[0034] Therefore, the housing (1100) and the piston (1200) of the air displacement pipette (1000) are cut off from contact with the liquid sample (LS), and only the tip portion (1300) that comes into contact with the liquid sample (LS) is replaced.

[0035] However, at this time, even if the piston (1200) is pulled or pushed to a certain extent by the air cushion (AC) inside the housing (1100), the liquid sample (LS) cannot flow in or out, making it difficult to flow in or out quantitatively.

[0036] In contrast, the present invention can reduce the volume of the air cushion (AC) inside the housing (1100) and can dispense a relatively more precise amount of liquid sample (LS).

[0037] The piston core and the air displacement pipette equipped with the piston core according to the present invention will be described in more detail below with reference to FIG.

[0038] FIG. 2 is a cross-sectional view showing an air displacement pipette equipped with a piston core according to an exemplary embodiment of the present invention, FIG. 3 is an exploded perspective view of the piston core shown in FIG. 2, and FIG. 4 is a bottom plan view of the piston core pin shown in FIG. 3.

[0039] 2 to 4, an air displacement pipette 2000 according to an exemplary embodiment of the present invention includes a housing 1100 and a piston core 2100. Preferably, such an air displacement pipette 2000 may further include a tip portion 1300.

[0040] The housing (1100) has the piston core (2100) disposed inside and a step portion (SP) formed at the lower portion, thereby reducing the thickness. For example, the housing (1100) may be formed in a cylindrical shape, and may be formed in a cylindrical shape with a diameter gradually decreasing at the step portion (SP) at the lower portion, and then decreasing again. The shape and size of the housing (1100) are not particularly limited, and a conventional pipette housing may be used.

[0041] The piston core (2100) according to an exemplary embodiment of the present invention includes a piston (2120), a piston core pin (2110), and a pusher rod (2121).

[0042] The piston (2120) is tightly attached to the inner wall of the housing (1100) so that the air in the air cushion (AC) at the bottom does not flow to the top. For this purpose, the piston (2120) can be made of an elastic material as shown in Figures 5 and 6, or alternatively, the piston (2120) can be made of a rigid material and an O-ring (OR) can be attached around it as shown in Figure 7.

[0043] The piston 2120 is formed to contact the inside of the pipette housing, and a hole h is formed on the inside. In one embodiment, when viewed in a plan view, the piston 2120 and the hole are circular, and the hole can be formed in the center of the piston.

[0044] The piston core pin (2110) is formed to have a rod-like shape with an elongated cross section having the same shape as the hole (h) of the piston (2120), and its lower part is supported by the housing (1100), and an air path (AP) through which air can pass is formed at the lower part. For example, the piston core pin (2110) may be formed in a cylindrical rod shape, and the lower part of the piston core pin (2110) may be changed according to the shape of the housing (1100).

[0045] For example, the lower part of the piston core pin (2110) may have a reduced diameter to form an inclined part in accordance with the shape of the step part (SP) of the housing (1100). Also, a groove may be formed in the inclined part to form an air path (AP) as shown in Figs. 3 and 4. The air path (AP) may be formed in a plurality of parts, for example, at the vertices of a regular polygon. However, the position and shape of such an air path (AP) are merely exemplary, and the shape and number are not particularly limited as long as the air of the air cushion (AC) below the piston (2120) inside the housing (1100) flows to the tip part (1300).

[0046] The pusher rod 2121 moves the piston 2120 inside the housing 1100. The pusher rod 2121 is connected to an external driving motor (not shown) and moves linearly.

[0047] In FIG. 1, one pusher rod (2121) is formed in the center of the piston (2120), but in the present invention, since a hole (h) is formed in the center of the piston (2120), it is preferable that a plurality of pusher rods (2121) for moving the piston (2120) are arranged symmetrically. That is, a plurality of pusher rods (2121) can be formed along the outer side of the piston (2120). Although two pusher rods are illustrated in FIG. 3 for convenience, a greater number of pusher rods can be formed. Such pusher rods can be connected to each other at the upper part and driven as one.

[0048] Alternatively, the pusher rod (2121) may be cylindrical and connected to the piston (2120) such that the hole is disposed inside.

[0049] The tip part (1300) is detachably fastened to the lower part of the housing (1100) and contacts the liquid sample (AS). Since the tip part (1300) contacts the liquid sample (AS), it can be used once and replaced to prevent contamination.

[0050] FIG. 5 is a side view showing another embodiment of the piston shown in FIG. 3, FIG. 6 is a side view showing yet another embodiment of the piston shown in FIG. 3, and FIG. 7 is a cross-sectional view showing yet another embodiment of the piston shown in FIG. 3.

[0051] As an example, the side of the piston (2120) may have a protruding shape at the center as shown in Fig. 5. Also, as shown in Fig. 6, the side of the piston (2120) may have a side groove (SG) formed at the center.

[0052] In this case, movement is easier than when the side of the piston (2120) is entirely in contact with the inside of the housing, and in particular, when the side groove (SG) of FIG. 6 is formed, the upper and lower parts of the side groove (SG) are in contact with the inside of the housing, effectively blocking air.

[0053] 7, O-rings (OR) may be attached to the outer and inner surfaces of the piston (2120). In this case, the piston (2120) body may be made of a rigid material, and the O-rings (OR) may be made of an elastic ductile material.

[0054] Thus, the piston core of the present invention allows for more precise dispensing of liquid samples by reducing the volume of the air cushion under the piston.

[0055] Moreover, the present invention can be easily attached to a conventional pipette without replacing the entire pipette, thereby improving the performance of a conventional biological sample dispensing device.

[0056] In the above detailed description of the present invention, a preferred embodiment of the present invention has been described with reference to the above. However, a person skilled in the art or having ordinary knowledge in the art will understand that the present invention can be modified and changed in various ways without departing from the spirit and technical scope of the present invention as described in the claims below.

Claims

1. a piston formed in contact with an inner surface of the pipette housing and having a hole formed therein; a piston core pin having a rod-like shape with a cross section having the same shape as the hole of the piston extended therefrom, a lower portion of which is supported by the pipette, and an air path through which air can pass is formed at the lower portion; and a pusher rod for moving the piston within the pipette housing. Piston core.

2. 2. The piston core according to claim 1, wherein, in a plan view, the piston and the hole are circular, and the hole is formed in a central portion of the piston.

3. The piston core according to claim 2 , wherein the pusher rod is formed in a plurality of pieces along the outer periphery of the piston.

4. The piston core according to claim 2 , wherein the pusher rod is cylindrical and is coupled to the piston such that the hole is disposed inside the pusher rod.

5. 2. The piston core according to claim 1, wherein the side surface of the piston has a shape in which a central portion protrudes.

6. The piston core according to claim 1 , wherein a side groove is formed in a central portion of the side surface of the piston.

7. 2. The piston core according to claim 1, wherein O-rings are attached to the outer and inner surfaces of the piston.

8. 2. The piston core according to claim 1, wherein the lower portion of the piston core pin is inclined so as to be supported by a step of the pipette.

9. The piston core according to claim 8, wherein the air path is formed in a plurality of parts.

10. A piston core according to any one of claims 1 to 9. The piston core is disposed inside the housing, and a step portion is formed at a lower portion of the housing, the thickness of which is reduced. Air displacement pipette.

11. 11. The air displacement pipette of claim 10, further comprising a tip portion detachably fastened to the lower portion of the housing and adapted to contact a liquid sample.

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