Sealing structure for manual pipettor

Abstract

The sealing structure comprises a piston rod located in a shell handle, the piston rod comprises an upper piston part and a lower piston part, the upper end of the upper piston part is connected with an adjusting nut, and the lower end of the lower piston part is inserted into a liquid suction cavity channel of an annular pipe connecting piece. An annular installation groove is formed in the upper end face of the annular pipe connecting piece, a sealing ring is installed in the annular installation groove, a polytetrafluoroethylene cushion block is arranged at the upper end of the sealing ring, the lower end of the upper piston part is sleeved with the polytetrafluoroethylene cushion block, and the upper end face of the sealing ring makes contact with the bottom face of the polytetrafluoroethylene cushion block. An annular connecting groove is formed in the upper end of the polytetrafluoroethylene cushion block, a compression spring is connected in the annular connecting groove, and the sealing ring is a Y-shaped sealing ring. According to the sealing ring with the Y-shaped structure, the wear resistance and the air tightness of the piston are enhanced, the loss of rubber is reduced, the service life of the whole pipettor is prolonged, the consistency of the operation hand feeling is kept, and the pipetting accuracy is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of manual pipettes, and more specifically, to a sealing structure for a manual pipette. Background Art

[0002] In the current pipette structure, the sealing of most manual pipettes is achieved by a general O-ring tightly fitting with the piston to form a vacuum state, and then the piston moves up and down to form an air negative pressure to complete liquid suction and discharge. An inevitable drawback of this method is that the rubber itself is a soft body and needs to tightly hold the piston with interference to form an effective seal. When the piston moves up and down, it frequently rubs against the O-ring, causing wear to the O-ring. As the number of uses increases, the difference in the feel of the operation button becomes greater, and the error in liquid transfer accuracy becomes greater. Summary of the Utility Model

[0003] In view of the above technical problems in the related art, the utility model provides a sealing structure for a manual pipette, which can solve the above problems.

[0004] To achieve the above technical objectives, the technical solution of the utility model is realized as follows:

[0005] A sealing structure for a manual pipette includes a piston rod located inside the handle of the outer shell. The piston rod includes an upper piston part and a lower piston part. The upper end of the upper piston part is connected to an adjusting nut, and the lower end of the lower piston part is inserted into the liquid suction cavity of a ring pipe connector. An annular installation groove is provided on the upper end surface of the ring pipe connector, and a sealing ring is installed in the annular installation groove. A polytetrafluoroethylene pad is provided at the upper end of the sealing ring, and the polytetrafluoroethylene pad is sleeved on the lower end of the upper piston part. The upper end surface of the sealing ring contacts the bottom surface of the polytetrafluoroethylene pad. An annular connection groove is provided at the upper end of the polytetrafluoroethylene pad, and a compression spring is connected in the annular connection groove. The sealing ring is a Y-shaped sealing ring, which includes a first sealing part installed in the annular installation groove and a second sealing part abutted against the outer wall of the upper piston part. The cross-section of the second sealing part is a strip inclined towards the upper piston part, and an annular groove is provided between the first sealing part and the second sealing part.

[0006] Further, the upper piston part is a hollow cylindrical structure, and the outer diameter of the upper piston part is larger than the outer diameter of the lower piston part.

[0007] Further, a stroke space for the movement of the upper piston part is provided inside the upper end of the ring pipe connector, and a clamping piece is connected to the outside of the upper end of the ring pipe connector.

[0008] Further, the upper end of the compression spring abuts against the convex block of the clamping piece, and the lower end of the compression spring is located in the annular space formed by the annular connection groove and the clamping piece.

[0009] Further, the sealing ring is made of rubber material.

[0010] Further, the opening of the annular groove faces downward, and the annular groove communicates with the stroke space.

[0011] The beneficial effects of the present utility model: The Y-shaped structure sealing ring of this application enhances the wear resistance and airtightness of the piston, reduces the loss of rubber, increases the service life of the whole pipette, maintains the consistency of the operation feel, and improves the pipetting accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0013] The following further describes the present utility model in detail according to the drawings.

[0014] Figure 1 is a cross-sectional view of the manual pipette according to the embodiment of the present utility model;

[0015] Figure 2 is Figure 1 an enlarged view of part A in

[0016] Figure 3 is a cross-sectional view of the sealing ring according to the embodiment of the present utility model.

[0017] In the figure:

[0018] 100, outer shell handle; 200, piston rod; 210, upper piston part; 220, lower piston part; 300, adjusting nut; 400, ring pipe connector; 410, liquid suction cavity; 420, annular installation groove; 430, stroke space; 500, sealing ring; 510, first sealing part; 520, second sealing part; 530, annular groove; 600, PTFE spacer; 700, compression spring; 800, clamping piece; 810, convex block; 900, operation button. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0020] As Figure 1-2 shown, according to the present invention, a sealing structure for a manual pipette is disclosed, which includes a piston rod 200 located in the outer shell handle 100. The piston rod 200 includes an upper piston part 210 and a lower piston part 220. The upper end of the upper piston part 210 is connected to an adjusting nut 300, and the lower end of the lower piston part 220 is inserted into the liquid suction cavity 410 of the ring pipe connector 400. An annular installation groove 420 is formed on the upper end surface of the ring pipe connector 400, and a sealing ring 500 is installed in the annular installation groove 420. A polytetrafluoroethylene spacer 600 is provided at the upper end of the sealing ring 500. The polytetrafluoroethylene spacer 600 is sleeved on the lower end of the upper piston part 210. The upper end surface of the sealing ring 500 is in contact with the bottom surface of the polytetrafluoroethylene spacer 600. An annular connection groove is provided at the upper end of the polytetrafluoroethylene spacer 600, and a compression spring 700 is connected in the annular connection groove. The sealing ring 500 is a Y-shaped sealing ring. The sealing ring 500 includes a first sealing part 510 installed in the annular installation groove 420 and a second sealing part 520 abutted against the outer wall of the upper piston part 210. The cross section of the second sealing part 520 is a strip inclined towards the upper piston part 210. An annular groove 530 is provided between the first sealing part 510 and the second sealing part 520.

[0021] Embodiment 1:

[0022] In this application, by pressing the operation button 900, the piston rod 200 moves up and down to form air negative pressure to complete liquid suction and discharge. During the up and down movement of the piston rod 200, the lower end of the upper piston portion 210 moves in the stroke space 430. To ensure good air negative pressure, the upper end of the annular pipe connector 400 needs to be sealed with the lower end of the upper piston portion 210. In this application, a composite sealing structure of a sealing ring 500 and a polytetrafluoroethylene spacer 600 is used for sealing. Specifically, an annular installation groove 420 is formed on the upper end surface of the annular pipe connector 400, and a sealing ring 500 is installed in the annular installation groove 420 to form the first seal. The second sealing portion 520 of the Y-shaped sealing ring 500 is in surrounding contact with the outer wall of the upper piston portion 210. The second sealing portion 520 is a thin-walled rubber with flexible elastic memory. During the liquid transfer process, the air pressure in the piston cylinder rebounds. The second sealing portion 520 (thin-walled rubber) of the Y-shaped sealing ring 500 expands under the air pressure, and the wrapping of the Y-shaped sealing ring and the outer wall of the upper piston portion 210 will be tighter, which also ensures the sealing performance and enables easy operation of liquid suction and discharge. Then, a polytetrafluoroethylene spacer 600 is arranged at the upper end of the sealing ring 500, so that the entire polytetrafluoroethylene spacer 600 is sleeved on the lower end of the upper piston portion 210 to form the second seal.

[0023] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A sealing structure for a manual pipette, comprising a piston rod (200) located in a housing handle (100), the piston rod (200) comprising an upper piston portion (210) and a lower piston portion (220), wherein the upper end of the upper piston portion (210) is connected to an adjusting nut (300), the lower end of the lower piston portion (220) is inserted into a liquid suction cavity (410) of a ring tube connector (400), and an annular mounting groove (420) is formed on the upper end surface of the ring tube connector (400) A sealing ring (500) is installed in the annular mounting groove (420), a polytetrafluoroethylene pad (600) is provided at the upper end of the sealing ring (500), the polytetrafluoroethylene pad (600) is sleeved on the lower end of the upper piston part (210), the upper end surface of the sealing ring (500) is in contact with the bottom surface of the polytetrafluoroethylene pad (600), an annular connecting groove is provided at the upper end of the polytetrafluoroethylene pad (600), a compression spring (700) is connected to the annular connecting groove, characterized in that: The sealing ring (500) is a Y-shaped sealing ring, comprising a first sealing portion (510) installed in the annular mounting groove (420) and a second sealing portion (520) abutting against the outer wall of the upper piston portion (210), wherein the cross section of the second sealing portion (520) is a strip shape inclined toward the upper piston portion (210), and an annular groove (530) is provided between the first sealing portion (510) and the second sealing portion (520).

2. A sealing structure for a manual pipette according to claim 1, characterized in that: The upper piston part (210) is a hollow cylindrical structure, and the outer diameter of the upper piston part (210) is greater than the outer diameter of the lower piston part (220).

3. A sealing structure for a manual pipette according to claim 1, characterized in that: A travel space (430) for movement of the upper piston part (210) is provided on the inner side of the upper end of the annular tube connecting piece (400), and a clamping piece (800) is connected to the outer side of the upper end of the annular tube connecting piece (400).

4. A sealing structure for a manual pipette according to claim 3, characterized in that: The upper end of the compression spring (700) abuts against the protrusion (810) of the clamping plate (800), and the lower end of the compression spring (700) is located in the annular space formed by the annular connecting groove and the clamping plate (800).

5. A sealing structure for a manual pipette according to claim 1, characterized in that: The sealing ring (500) is made of rubber material.

6. A sealing structure for a manual pipette according to claim 3, characterized in that: The opening of the annular groove (530) faces downward, and the annular groove (530) is in communication with the travel space (430).

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