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 the piston and the sample, thereby reducing the compressibility and improving the efficiency of quantitatively dispensing the sample. [Background technology]

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

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

[0004] In the direct displacement method, the piston inside the pipette moves up and down to aspirate and dispense the liquid sample, with the end of the piston directly contacting the liquid sample, and no air cushion exists between the end of the piston and the liquid sample. This direct displacement method can aspirate and dispense samples of relatively precise volumes and can repeatedly dispense the same amount of sample multiple times depending on the dispenser settings. However, it can only be used for a single sample and must be disposed of to prevent cross-contamination. Therefore, for automated medical devices that dispense biological samples, where contamination is extremely important, the need to replace and dispose of the entire pipette creates a huge waste stream and is costly.

[0005] In contrast, the air displacement method uses the difference in volume created by the air cushion generated by the up and down movement of the piston inside the pipette to aspirate the sample once and then dispense it into multiple locations. In other words, there is an air cushion between the end of the piston and the liquid sample, and when the piston is compressed or pulled, the pressure caused by the change in volume of the internal air cushion causes the liquid sample to be dispensed.

[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 automated 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 the liquid sample using the pressure of the internal air cushion, which is significantly disadvantageous compared to the direct replacement method when it comes to 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 has a rod-like shape extending from a cross section having the same shape as the hole of the piston, and its lower portion is supported by the pipette, and an air path through which air can pass is formed at the lower portion. 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, a plurality of pusher rods may be formed along the outer periphery of the piston.

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

[0015] In one embodiment, 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] In one embodiment, O-rings may be attached to the outer and inner surfaces of the piston.

[0018] In one embodiment, 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 described above and a housing, wherein the housing has a stepped portion formed at the bottom thereof and a reduced thickness, with the piston core disposed inside.

[0021] As an example, the air displacement pipette may further include a tip portion that is detachably fastened to the lower portion of the housing and that comes into contact with the liquid sample. [Effects of the Invention]

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

[0023] Furthermore, the performance of conventional biological sample dispensing devices can be improved by simply attaching the device to conventional pipettes without replacing the entire pipette. [Brief explanation of the drawings]

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

[0025] Because 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 herein. 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, and alternatives within the spirit and technical scope of the present invention. In the description of each drawing, similar reference numerals are used for similar components. In the accompanying drawings, the dimensions of structures may be exaggerated to enhance clarity of the present invention.

[0026] Terms such as "first," "second," and the like may be used to describe various components, but the components should not be limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be designated a "second component," and similarly, a second component may be designated 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 a feature, numeral, step, operation, component, or combination thereof described in the specification, but should be understood not to preclude the presence or addition of one or more other features, numerals, step, operation, component, or combination thereof. Furthermore, the meaning of "connected" or "coupled" between A and B includes not only direct connection or coupling between A and B, but also the connection or coupling between A and B by including another component C between 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 this invention pertains. Terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly defined in this application. In addition, in claims of method inventions, unless expressly bound to a specific order, the order of the steps may be reversed.

[0029] Furthermore, the configurations individually explained 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 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 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 stepped portion SP formed at the bottom, reducing its thickness. For example, the housing 1100 may be formed cylindrically, with the diameter gradually tapering at the stepped portion SP at the bottom, and then tapering again. The shape and size of the housing 1100 are not particularly limited, and conventional pipette housings can 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 fitted to the inner wall of the housing 1100 so that the air in the air cushion AC at the bottom does not flow upward. For this purpose, the piston 2120 can be made of an elastic material as shown in Figures 5 and 6. Alternatively, the piston 2120 can be made of a rigid material and fitted with an O-ring OR 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 inside. In one embodiment, the piston 2120 and the hole are circular when viewed from above, and the hole can be formed in the center of the piston.

[0044] The piston core pin 2110 is formed in a rod 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 in 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 depending on the shape of the housing 1100.

[0045] For example, the diameter of the lower portion of the piston core pin (2110) may be reduced to form a sloped portion corresponding to the shape of the stepped portion (SP) of the housing (1100). Also, grooves may be formed in the sloped portion to form air paths (AP) as shown in FIGS. 3 and 4. A plurality of air paths (AP) may be formed, for example, at the vertices of a regular polygon. However, the position and shape of the air paths (AP) are merely exemplary, and the shape and number of the air paths (AP) are not particularly limited as long as the air in the air cushion (AC) below the piston (2120) inside the housing (1100) flows to the tip portion (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. However, 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 outside of the piston 2120. Although two pusher rods are shown in FIG. 3 for convenience, a greater number of pusher rods can be formed. These pusher rods can be connected to each other at the top and driven as one.

[0048] Alternatively, the pusher rod (2121) may be cylindrical and may be coupled to the piston (2120) with the hole disposed inside.

[0049] The tip part 1300 is detachably fastened to the lower part of the housing 1100 and comes into contact with the liquid sample AS. Since the tip part 1300 comes into contact with the liquid sample AS, it can be used once and then 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, the piston (2120) can move more easily than when the entire side of the piston is tightly attached to the inside of the housing, and in particular, when the side groove (SG) of Figure 6 is formed, the upper and lower parts of the side groove (SG) are tightly attached to 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 below the piston.

[0055] Furthermore, the performance of conventional biological sample dispensing devices can be improved by simply attaching the device to conventional pipettes without replacing the entire pipette.

[0056] The above detailed description of the present invention has been given with reference to preferred embodiments of the present invention, but it will be understood by those skilled in the art or those with ordinary knowledge in the art 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 set forth in the claims below.

Claims

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

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

3. The piston core according to claim 2 , wherein a plurality of the pusher rods are formed along the outer periphery of the piston.

4. The piston core according to claim 2 , wherein the pusher rod has a cylindrical shape and is coupled to the piston so 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 the center portion protrudes.

6. The piston core according to claim 1 , wherein a side groove is formed in the center 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 housing.

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 housing has a stepped portion formed at a lower portion thereof and a reduced thickness, and the piston core is disposed inside the housing. 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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