Piston rod sealing structure and pipettor

Abstract

The utility model discloses a piston rod sealing structure and a pipettor, and relates to the technical field of pipettors. The piston rod extends into the cylinder body from one end of the cylinder body and is in sliding fit with the cylinder body; the two layers of heat shrink tubes are arranged on the outer side of the cylinder body in an overlapped mode, and the sides, extending out of the end face of the cylinder body, of the two layers of heat shrink tubes form extending parts; the plurality of first sealing rings are located on the extension part, and the plurality of first sealing rings are wrapped in the two layers of heat shrink tubes; when the piston rod is in sliding fit with the cylinder body, the outer wall of the piston rod is tightly attached to the extending part. The piston rod sealing structure isolates the sealing ring and prolongs the service life.

Description

Technical Field

[0001] The utility model relates to the technical field of pipettes, in particular to a piston rod sealing structure and a pipette applying the piston rod sealing structure. Background Art

[0002] A pipette, also called a pipette gun, is a measuring tool that transfers liquid from its original container to another container within a certain range.

[0003] The pipette uses a piston structure to absorb or discharge liquid. Specifically, the piston rod slides relative to the cylinder body, changing the volume of the cavity and thus achieving liquid absorption or discharge. There is a certain movable gap between the piston rod and the cylinder body, and a sealing ring is used to achieve a tight fit. When a corrosive and volatile liquid is absorbed, the vaporized liquid rises through the gap between the piston rod and the cylinder body, thereby contacting the sealing ring. The sealing ring will corrode and age over time in this environment, resulting in a short service life. Furthermore, it is currently difficult to achieve a sealing ring that is resistant to dissolution by reagents while also having good elasticity. Therefore, it is currently difficult to achieve a reliable sealing structure that is resistant to dissolution by reagents in a small space. Utility Model Content

[0004] The main purpose of the utility model is to provide a piston rod sealing structure, aiming to provide a piston rod sealing structure which can isolate the sealing ring and extend the service life.

[0005] To achieve the above-mentioned purpose, the present invention proposes a piston rod sealing structure, which includes:

[0006] Cylinder body;

[0007] a piston rod extending from one end of the cylinder body and slidingly engaging with the cylinder body;

[0008] A heat shrink tube, the heat shrink tube having two layers and being overlapped and arranged on the outer side of the cylinder body, the two layers of the heat shrink tube forming an extension portion on one side extending out of the end surface of the cylinder body;

[0009] a first sealing ring, wherein the first sealing ring is provided in plurality and is located on the extension portion, and the two layers of the heat shrink tube wrap the plurality of the first sealing rings;

[0010] When the piston rod is slidably engaged with the cylinder body, the outer wall of the piston rod is tightly fitted with the extending portion.

[0011] Optionally, the heat shrink tube includes:

[0012] a first heat shrink tube, the first heat shrink tube comprising a first wrapping portion and a first extending portion connected to each other, the first wrapping portion being disposed on the outer wall of the cylinder body, the first extending portion being tightly fitted with the outer wall of the piston rod, and a plurality of first sealing rings being disposed on the outer side of the first extending portion;

[0013] The second heat shrink tube includes a second wrapping portion, a pressing portion and a second extension portion that are connected to each other. The second wrapping portion is arranged on the outside of the first wrapping portion. The second extension portion is tightly fitted with the outer wall of the piston rod. The pressing portion is arranged between the second wrapping portion and the second extension portion, and is wrapped around the outside of multiple first sealing rings.

[0014] Optionally, there are three first sealing rings.

[0015] Optionally, the materials of the two layers of heat shrink tubes are both polyolefin.

[0016] Optionally, the material of the heat shrink tube located on the inner side is Teflon, and the material of the heat shrink tube located on the outer side is polyolefin.

[0017] Optionally, the piston rod sealing structure further includes:

[0018] A joint having a connecting portion, wherein the connecting portion is provided at the other end of the cylinder body;

[0019] a second sealing ring, the second sealing ring being arranged on the outer side of the connecting portion;

[0020] The first heat shrink tube further includes a third extension portion, which is provided at an end of the first wrapping portion away from the first extension portion. The third extension portion is provided on the outside of the connecting portion and presses the second sealing ring.

[0021] Optionally, the second heat shrink tube further includes a fourth extension portion, the fourth extension portion is provided at an end of the second wrapping portion away from the second extension portion, and the fourth extension portion is provided on the outside of the third extension portion.

[0022] The present utility model also provides a pipette, which includes the piston rod sealing structure as described above.

[0023] The technical solution of the present utility model includes a cylinder body, a piston rod, a heat shrink tube and a first sealing ring. Two layers of heat shrink tubes are overlapped and arranged on the outside of the cylinder body, and an extension portion is formed on the outside of the end face of the cylinder body to wrap multiple sealing rings. When the piston rod slides relative to the cylinder body, the extension portion fits tightly with the outer wall of the piston rod. Since two layers of heat shrink tubes are used to wrap the first sealing ring to isolate it, the technical problems in the prior art that the sealing ring will corrode and age when it comes into contact with corrosive gases and the service life is short are effectively solved, thereby achieving the technical effect of isolating the sealing ring and extending its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a structural diagram of an embodiment of the piston rod sealing structure of the present utility model;

[0025] Figure 2 This is a schematic diagram of the disassembled structure of the piston rod sealing structure of the utility model;

[0026] Figure 3 This is a schematic diagram of the main view of the piston rod sealing structure of the utility model;

[0027] Figure 4 for Figure 3 Schematic cross-sectional view along line AA;

[0028] Figure 5 for Figure 4 A partial enlarged view of point A in the middle;

[0029] Figure 6 for Figure 4 A partial enlarged view of point B in the middle;

[0030] Description of Figure Numbers:

[0031] Piston rod sealing structure 100; cylinder body 10; piston rod 20; first heat shrink tube 30; first wrapping portion 31; first extension portion 32; third extension portion 33; second heat shrink tube 40; second wrapping portion 41; pressing portion 42; second extension portion 43; fourth extension portion 44; first sealing ring 50; joint 60; second sealing ring 70. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0034] In this utility model, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0035] In addition, in this utility model, the descriptions of "first" and "second" are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0036] The present utility model provides a piston rod sealing structure 100 .

[0037] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0038] In the embodiment of the present utility model, as Figures 1 to 6 As shown, the piston rod sealing structure 100 includes a cylinder body 10, a piston rod 20, a heat shrink tube and a first sealing ring 50, wherein the piston rod 20 extends from one end of the cylinder body 10 and slides together; the heat shrink tube has two layers and is overlapped on the outside of the cylinder body 10, and the two layers of heat shrink tube form an extension part on one side extending out of the end face of the cylinder body 10; there are multiple first sealing rings 50 and they are located in the extension part, and the two layers of heat shrink tube wrap the multiple first sealing rings 50 therein; when the piston rod 20 slides together relative to the cylinder body 10, the outer wall of the piston rod 20 fits tightly against the extension part.

[0039] It can be understood that the piston rod 20 slides relative to the cylinder body 10 to achieve liquid suction or discharge, and the extension part formed by the two layers of heat shrinkage tube is located at one end of the piston rod 20 and the cylinder body 10 that slide together. During the sliding cooperation of the piston rod 20, the extension part is tightly fitted with the outer wall of the piston rod 20 to achieve a sealing effect. The tight fit between the extension part and the piston rod 20 is specifically achieved by the heat shrinkage tube and the first sealing ring 50. The two layers of heat shrinkage tube wrap the first sealing ring 50 therein. The first sealing ring 50 has an elastic effect, so that the inner heat shrinkage tube can fit tightly with the outer wall of the piston rod 20. At the same time, the heat shrinkage tube located on the outside has a tightening effect, which pushes and squeezes the first sealing ring 50. Through this structure, the extension part and multiple first sealing rings 50 are used as a whole to achieve a sealing effect between the piston rod 20 and the cylinder body 10.

[0040] The technical solution of the present invention includes a cylinder body 10, a piston rod 20, a heat shrink tube and a first sealing ring 50. Two layers of heat shrink tubes are overlapped and arranged on the outside of the cylinder body 10, and an extension portion is formed on the outside of the end face of the cylinder body 10 to wrap multiple sealing rings. When the piston rod 20 slides relative to the cylinder body 10, the extension portion fits tightly against the outer wall of the piston rod 20. Since two layers of heat shrink tubes are used to wrap the first sealing ring 50 to isolate it, the technical problem of corrosion aging and short service life of the sealing ring when it comes into contact with corrosive gas in the prior art is effectively solved, thereby achieving the technical effect of isolating the sealing ring and extending its service life.

[0041] In the embodiment of the present utility model, as Figure 2 、 Figures 4 to 6 As shown, the heat shrink tube includes a first heat shrink tube 30 and a second heat shrink tube 40, wherein the first heat shrink tube 30 includes a first wrapping portion 31 and a first extension portion 32 connected to each other, the first wrapping portion 31 is arranged on the outer wall of the cylinder body 10, and the first extension portion 32 is tightly fitted with the outer wall of the piston rod 20, and there are multiple first sealing rings 50 and they are arranged on the outside of the first extension portion 32; the second heat shrink tube 40 includes a second wrapping portion 41, a pressing portion 42 and a second extension portion 43 connected to each other, the second wrapping portion 41 is arranged on the outside of the first wrapping portion 31, the second extension portion 43 is tightly fitted with the outer wall of the piston rod 20, the pressing portion 42 is arranged between the second wrapping portion 41 and the second extension portion 43, and is wrapped around the outside of multiple first sealing rings 50.

[0042] During assembly of the present invention, the piston rod 20 is first extended into the cylinder body 10, and the first heat shrink tube 30 is installed on the outer wall of the cylinder body 10. The first wrapping portion 31 is fixed to the outer wall of the cylinder body 10 through the heat shrinkage pressure, and the piston rod 20 and the first extension portion 32 are tightly fitted and slidably matched. Then, multiple first sealing rings 50 are installed on the outside of the first extension portion 32. The elastic force of the first sealing ring 50 further reduces the gap between the first extension portion 32 and the piston rod 20 to achieve a tight fit. Finally, the second heat shrink tube 40 is installed on the outside of the first heat shrink tube 30. The second wrapping portion 41 is fixed to the outside of the first wrapping portion 31 through the heat shrinkage pressure. The part located on the outside of the first sealing ring 50 forms a pressing portion 42 by heat shrinkage, so that multiple first sealing rings 50 are pressed between the pressing portion 42 and the first extension portion 32, and the piston rod 20 and the second extension portion 43 are tightly fitted and slidably matched.

[0043] In the embodiment of the present utility model, as Figure 6 As shown, there are three first sealing rings 50. Two adjacent first sealing rings 50 fit tightly together.

[0044] In the present invention, the two layers of heat shrink tubing can be made of the same material or different materials. Specifically, when the two layers of heat shrink tubing are made of the same material, polyolefin can be used. When the two layers of heat shrink tubing are made of different materials, the inner heat shrink tubing is made of Teflon, while the outer heat shrink tubing is made of polyolefin. Compared to polyolefin, Teflon is more wear-resistant, corrosion-resistant, and high-temperature resistant. The inner heat shrink tubing will come into contact with vaporized corrosive liquids. Using Teflon can further improve corrosion resistance and extend service life.

[0045] In the embodiment of the present utility model, as Figure 1 、 Figure 2 、 Figure 4 and Figure 5 As shown, the piston rod sealing structure 100 also includes a joint 60 and a second sealing ring 70, wherein the joint 60 has a connecting portion, which is arranged at the other end of the cylinder body 10; the second sealing ring 70 is arranged on the outside of the connecting portion; the first heat shrink tube 30 also includes a third extension portion 33, which is arranged at one end of the first wrapping portion 31 away from the first extension portion 32, and the third extension portion 33 is arranged on the outside of the connecting portion and presses the second sealing ring 70.

[0046] It can be understood that the present invention is assembled with the suction head through the joint 60, and the connection and fixation between the suction head and the cylinder body 10 is also achieved by the heat shrink tube, that is, the heat shrink tube forms an extension portion on both side end faces of the cylinder body 10, and the joint 60 is fixed to the cylinder body 10 by heat shrink molding. At the same time, the first heat shrink tube 30 presses the second sealing ring 70 to play a sealing role, thereby preventing liquid from flowing out of the gap between the joint 60 and the cylinder body 10.

[0047] In the embodiment of the present utility model, as Figure 5 As shown, the second heat shrink tube 40 further includes a fourth extension portion 44 . The fourth extension portion 44 is disposed at an end of the second wrapping portion 41 away from the second extension portion 43 . The fourth extension portion 44 is disposed outside the third extension portion 33 .

[0048] In the present invention, both the inner and outer layers of heat shrink tubes are provided with extension portions at the connection position of the joint 60 , which can improve the stability of the structural connection and enhance the sealing effect.

[0049] The present invention further provides a pipette (not shown in the figures), which includes a piston rod sealing structure 100. The specific structure of the piston rod sealing structure 100 is referred to the above embodiments. Since the present pipette adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described one by one here.

[0050] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by utilizing the contents of the present invention specification and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A piston rod sealing structure, characterized in that: The piston rod sealing structure comprises: Cylinder body; A piston rod, the piston rod extends from one end of the cylinder body and slides into the cylinder body; A heat shrink tube, the heat shrink tube having two layers and being overlapped and arranged on the outer side of the cylinder body, the two layers of the heat shrink tube forming an extension portion on one side extending out of the end surface of the cylinder body; A first sealing ring, wherein the first sealing ring is in plurality and is located at the extension portion, and the two layers of the heat shrink tube wrap the plurality of the first sealing rings; When the piston rod is slidably matched with the cylinder body, the outer wall of the piston rod is tightly fitted with the extension part.

2. The piston rod sealing structure according to claim 1, characterized in that: The heat shrink tube comprises: A first heat shrinkable tube, the first heat shrinkable tube comprising a first wrapping portion and a first extending portion connected to each other, the first wrapping portion being arranged on the outer wall of the cylinder body, the first extending portion being tightly fitted with the outer wall of the piston rod, and a plurality of first sealing rings being arranged on the outer side of the first extending portion; The second heat shrinkable tube comprises a second wrapping portion, a clamping portion and a second extending portion which are connected to each other, the second wrapping portion being arranged on the outside of the first wrapping portion, the second extending portion being tightly fitted with the outer wall of the piston rod, the clamping portion being arranged between the second wrapping portion and the second extending portion, and being wrapped around the outside of the plurality of first sealing rings.

3. The piston rod sealing structure according to claim 1, characterized in that: There are three first sealing rings.

4. The piston rod sealing structure according to claim 1, characterized in that: The materials of the two layers of heat shrink tubes are both polyolefin.

5. The piston rod sealing structure according to claim 1, characterized in that: The material of the heat shrink tube located on the inner side is Teflon, and the material of the heat shrink tube located on the outer side is polyolefin.

6. The piston rod sealing structure according to claim 2, characterized in that: The piston rod sealing structure also includes: A joint, the joint having a connecting portion, the connecting portion being arranged at the other end of the cylinder body; a second sealing ring, the second sealing ring being arranged on the outer side of the connecting portion; The first heat shrink tube further includes a third extension portion, which is disposed at an end of the first wrapping portion away from the first extension portion, and the third extension portion is disposed on the outer side of the connecting portion and presses the second sealing ring.

7. The piston rod sealing structure according to claim 6, characterized in that: The second heat shrink tube further includes a fourth extension portion, which is disposed at an end of the second wrapping portion away from the second extension portion, and the fourth extension portion is disposed outside the third extension portion.

8. A pipette, characterized in that: The pipette comprises the piston rod sealing structure according to any one of claims 1 to 7.

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