High-precision piston injector for pipetting

Abstract

The high-precision piston injector comprises an injection cavity, an adapter, a piston assembly, a piston rod sleeve and a spring, the piston assembly comprises a piston head and a piston rod, and the injection cavity comprises a first cavity and a second cavity which are sequentially communicated; an adapter installation position is arranged at the end, away from the second cavity, of the first cavity, an avoiding groove is formed in the end, away from the abutting section, of the threaded section, and an oil storage groove is concavely formed in the position, corresponding to the avoiding groove, of the first cavity. The piston rod is sleeved with the piston rod sleeve, the end, close to the piston head, of the piston rod sleeve is provided with an abutting portion, the piston rod sleeve is sleeved with the spring and clamped between the abutting portion and the end, close to the second cavity, of the first cavity, and the end, away from the piston head, of the piston rod extends out of the second cavity. Direct friction between the piston rod and the injection cavity can be avoided, the service life of the injector is effectively prolonged, noise generated by friction between the spring and the piston rod when the spring is compressed can be avoided, and the mute effect is better.

Description

Technical Field

[0001] The invention relates to the technology of syringe field, in particular to a high-precision piston syringe for pipetting. Background Art

[0002] A pipette, also known as a pipette gun, is an instrument used to quantitatively transfer liquids. When conducting analytical testing research, a pipette is generally used to transfer small or trace amounts of liquid. Pipette can be divided into gas piston pipette and external piston pipette according to the principle. Gas piston pipette is mainly used for standard pipetting, and external piston pipette is mainly used to handle special liquids such as volatile, corrosive and viscous liquids.

[0003] The piston pipette in the prior art includes an injection cavity and a piston rod movably arranged in the injection cavity. The injection cavity is equipped with an adapter for matching with the tip head. The piston rod outer sleeve is provided with a spring, which is used to press the piston rod against the adapter. Under this structure, the spring will rub against the piston rod when compressed to produce noise, affecting the user's experience. In addition, friction between the piston rod and the injection cavity will cause the piston rod and the injection cavity to be worn after repeated use, affecting the service life of the piston pipette.

[0004] Therefore, it is necessary to design a new technical solution to solve the above problems. Summary of the invention

[0005] In view of this, the present invention aims at the deficiencies in the prior art, and its main purpose is to provide a high-precision piston syringe for pipetting, wherein an avoidance groove is provided at one end of the threaded section away from the abutment section, and an oil storage groove is recessed at the avoidance groove corresponding to the first cavity. The setting of the avoidance groove and the oil storage groove can allow grease at the piston head sealing ring to flow into, so as to prevent the grease from clogging the adapter when the piston head is moving, and a piston rod sleeve is provided on the piston rod outer sleeve, and the piston rod sleeve is made of self-lubricating material, which can not only avoid direct friction between the piston rod and the injection cavity, effectively increasing the life of the syringe, but also avoid noise generated by friction between the spring and the piston rod when compressed, and the mute effect is better. In addition, the setting of the first rough-machined surface and the second rough-machined surface can reduce the processing difficulty of the injection cavity and the piston rod sleeve. At the same time, the second rough-machined surface can reduce the friction area between the piston rod sleeve and the injection cavity, thereby further reducing the friction between the two and increasing the service life of the piston rod sleeve. The adapter is connected to the injection cavity by threads, which is simple to assemble and easy to maintain the piston head sealing ring and the piston rod sleeve.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: A high-precision piston syringe for pipetting, comprising an injection cavity, an adapter, a piston assembly, a piston rod sleeve and a spring, wherein the piston assembly comprises a piston head and a piston rod connected to the piston head, and the injection cavity comprises a first cavity and a second cavity which are connected in sequence; wherein: An adapter installation position is provided at one end of the first cavity away from the second cavity, the adapter installation position includes a first sealing ring groove and a threaded connection portion arranged in sequence, the adapter includes a main body and a mounting portion connected in sequence, an abutting section and a threaded section connected in sequence to the mounting portion, the abutting section covers the end of the first cavity away from the second cavity, an end of the threaded section close to the abutting section is provided with a second sealing ring groove corresponding to the first sealing ring groove, an adapter sealing ring is sandwiched between the first sealing ring groove and the second sealing ring groove, an avoidance groove is provided at one end of the threaded section away from the abutment section, and an oil storage groove is recessed at the first cavity corresponding to the avoidance groove; The piston head is located in the first cavity and can press against the end of the threaded section away from the abutting section. The outer periphery of the piston head is slidably connected to the first cavity through a piston head sealing ring. The piston rod sleeve is made of self-lubricating material. The piston rod sleeve is sleeved on the outer periphery of the piston rod. The end of the piston rod sleeve close to the piston head is provided with a pressing portion. The spring is sleeved on the outer periphery of the piston rod sleeve and clamped between the pressing portion and the end of the first cavity close to the second cavity. The elastic force of the spring presses the pressing portion against the piston head. A first rough-machined surface and a first fine-machined surface are sequentially arranged in the piston rod sleeve. The first fine-machined surface is arranged away from the piston head and fits the piston rod. A second rough-machined surface and a second fine-machined surface are sequentially arranged in the second cavity, the outer periphery of the piston rod sleeve is slidably connected to the second fine-machined surface, and one end of the piston rod away from the piston head extends out of the second cavity.

[0007] As a preferred embodiment, the main body is provided with a first channel and a second channel which are perpendicular to each other, the first channel is located at an end of the main body away from the mounting portion, the end of the second channel close to the first channel is connected to the first channel, the end of the second channel away from the first channel is exposed at the end of the threaded connection portion, and the piston head can block the end of the second channel away from the first channel.

[0008] As a preferred embodiment, the oil storage tank includes a first oblique section, a horizontal section, and a second oblique section connected in sequence, the inclination of the second oblique section is smaller than the inclination of the first oblique section, and the second oblique section is arranged away from the adapter and connected to the wall of the first cavity through an arc section.

[0009] As a preferred embodiment, a third sealing ring groove is provided on the outer periphery of the piston head, and the piston head sealing ring is sleeved in the third sealing ring groove. The end of the third sealing ring groove away from the piston rod is connected to the outer periphery of the piston head through a third oblique section, and the end of the third sealing ring groove close to the piston rod is connected to the outer periphery of the piston head through a fourth oblique section, and the inclination of the fourth oblique section is smaller than the inclination of the third oblique section.

[0010] As a preferred solution, a spring installation position is provided at one end of the first cavity close to the second cavity, the spring installation position is provided at the outer periphery of the second cavity, and the spring sleeve is clamped between the pressing portion and the spring installation position.

[0011] As a preferred solution, the injection cavity is provided with an air hole penetrating the first cavity, and the air hole is arranged close to the second cavity.

[0012] As a preferred solution, the second rough-machined surface is connected to the second fine-machined surface via an arc surface.

[0013] As a preferred solution, a rod cap mounting position is provided at one end of the piston rod away from the piston head, and a piston rod cap and a nut are sequentially provided on the periphery of the rod cap mounting position, and the nut fixes the piston rod cap to the rod cap mounting position.

[0014] As a preferred solution, the injection cavity, adapter and piston assembly are all made of stainless steel.

[0015] As a preferred solution, the injection cavity is made of 304 stainless steel, the adapter is made of 316L stainless steel, the piston assembly is made of 303 stainless steel, and the piston rod sleeve is made of POM.

[0016] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, it can be seen from the above technical solution that: Mainly, an avoidance groove is provided at one end of the threaded section away from the abutment section, and an oil storage groove is recessed at the avoidance groove corresponding to the first cavity. The avoidance groove and the oil storage groove can allow grease at the piston head sealing ring to flow in, so as to prevent the grease from clogging the adapter when the piston head moves. In addition, a piston rod sleeve is provided on the piston rod outer sleeve. The piston rod sleeve is made of self-lubricating material, which can avoid direct friction between the piston rod and the injection cavity, effectively increasing the life of the syringe, and avoid noise caused by friction between the spring and the piston rod when the spring is compressed, so as to achieve better silencing effect. In addition, the provision of the first rough-machined surface and the second rough-machined surface can reduce the processing difficulty of the injection cavity and the piston rod sleeve. At the same time, the second rough-machined surface can reduce the friction area between the piston rod sleeve and the injection cavity, thereby further reducing the friction between the two and increasing the service life of the piston rod sleeve. The adapter is connected to the injection cavity by threads, which is simple to assemble and easy to maintain the piston head sealing ring and the piston rod sleeve.

[0017] In order to more clearly illustrate the structural features and effects of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a three-dimensional schematic diagram of a preferred embodiment of the present invention; Figure 2 It is an exploded schematic diagram of a preferred embodiment of the present invention; Figure 3 It is a cross-sectional schematic diagram of a preferred embodiment of the present invention; Figure 4 yes Figure 3 A partial enlarged view of the middle A; Figure 5 yes Figure 3 A partial enlarged view of point B in the middle.

[0019] Description of the accompanying drawings: 10. Injection cavity 11. First cavity 111. Adapter installation position 112. First sealing ring groove 113. Threaded connection 114. Oil storage tank 115. First oblique section 116. Horizontal section 117. Second oblique section 118. Arc section 119, spring installation position 12, second cavity 121, second rough-machined surface 122, second fine-machined surface 123, curved surface 13, pores 20. Adapter 21. Main body 211, first channel 212, second channel 22. Mounting portion 221. Abutment section 222, threaded section 223, second sealing ring groove 224, avoidance groove 30, piston assembly 31. Piston head 311. Third sealing ring groove 312, third oblique section 313, fourth oblique section 32. Piston rod 321. Rod cap installation 33. Piston rod cap 34. Nut 40. Piston rod sleeve 41. Pressing part 42. First rough-machined surface 43. First fine-machined surface 50, spring 60, adapter seal 70. Piston head sealing ring. DETAILED DESCRIPTION

[0020] First of all, it should be noted that in the description of the present invention, the terms "up", "down", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships 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 direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0021] Please refer to Figures 1 to 5 As shown, it shows the specific structure of a preferred embodiment of the present invention, including an injection cavity 10, an adapter 20, a piston assembly 30, a piston rod sleeve 40 and a spring 50.

[0022] The piston assembly 30 includes a piston head 31 and a piston rod 32 connected to the piston head 31, and the injection cavity 10 includes a first cavity 11 and a second cavity 12 which are connected in sequence; wherein: An adapter installation position 111 is provided at one end of the first cavity 11 away from the second cavity 12, and the adapter installation position 111 includes a first sealing ring groove 112 and a threaded connection portion 113 arranged in sequence. The adapter 20 includes a main body 21 and a mounting portion 22 connected in sequence, and the mounting portion 22 is connected in sequence to an abutting section 221 and a threaded section 222, and the abutting section 221 covers the end of the first cavity 11 away from the second cavity 12, and an end of the threaded section 222 close to the abutting section 221 is provided with a second sealing ring groove 223 corresponding to the first sealing ring groove 112, and an adapter sealing ring 60 is sandwiched between the first sealing ring groove 112 and the second sealing ring groove 223, and an avoidance groove 224 is provided at one end of the threaded section 222 away from the abutment section 221, and an oil storage groove 114 is recessed at the place of the first cavity 11 corresponding to the avoidance groove 224; The piston head 31 is located in the first cavity 11 and can press against the end of the threaded section 222 away from the abutting section 221. The outer periphery of the piston head 31 is slidably connected to the first cavity 11 through a piston head sealing ring 70. The piston rod sleeve 40 is made of a self-lubricating material. The piston rod sleeve 40 is sleeved on the outer periphery of the piston rod 32. The end of the piston rod sleeve 40 close to the piston head 31 is provided with a pressing portion 41. The spring 50 is sleeved on the outer periphery of the piston rod sleeve 40 and clamped between the pressing portion 41 and the end of the first cavity 11 close to the second cavity 12. The elastic force of the spring 50 presses the pressing portion 41 against the piston head 31. A first rough-machined surface 42 and a first fine-machined surface 43 are sequentially arranged in the piston rod sleeve 40. The first fine-machined surface 43 is arranged away from the piston head 31 and fits the piston rod 32. The second cavity 12 is provided with a second rough-machined surface 121 and a second fine-machined surface 122 arranged in sequence. The outer periphery of the piston rod sleeve 40 is slidably connected to the second fine-machined surface 122 , and the end of the piston rod 32 away from the piston head 31 extends out of the second cavity 12 .

[0023] See also Figure 3 As shown, the main body 21 is provided with a first channel 211 and a second channel 212 which are perpendicular to each other, the first channel 211 is located at an end of the main body 21 away from the mounting portion 22, the end of the second channel 212 close to the first channel 211 is connected to the first channel 211, the end of the second channel 212 away from the first channel 211 is exposed at the end of the threaded connection portion 113, and the piston head 31 can block the end of the second channel 212 away from the first channel 211; wherein, the adapter 20 is used to adapt to the tip head.

[0024] See also Figure 2 and Figure 4 As shown, the oil storage tank 114 includes a first oblique section 115, a horizontal section 116, and a second oblique section 117 which are connected in sequence. The inclination of the second oblique section 117 is smaller than that of the first oblique section 115. The second oblique section 117 is arranged away from the adapter 20 and is connected to the wall of the first cavity 11 through the arc section 118. A third sealing ring groove 311 is opened on the periphery of the piston head 31. The piston head sealing ring 70 is sleeved in the third sealing ring groove 311. The end of the third sealing ring groove 311 away from the piston rod 32 is connected to the periphery of the piston head 31 through the third oblique section 312. The end of the third sealing ring groove 311 close to the piston rod 32 is connected to the periphery of the piston head 31 through the fourth oblique section 313. The inclination of the fourth oblique section 313 is smaller than that of the third oblique section 312.

[0025] See also Figure 3 As shown, a spring mounting position 119 is provided at one end of the first cavity 11 close to the second cavity 12, and the spring mounting position 119 is provided on the outer periphery of the second cavity 12. The spring 50 is clamped between the pressing portion 41 and the spring mounting position 119. The injection cavity 10 is provided with an air hole 13 that passes through the first cavity 11, and the air hole 13 is provided close to the second cavity 12. A rod cap mounting position 321 is provided at one end of the piston rod 32 away from the piston head 31, and a piston rod cap 33 and a nut 34 are sequentially provided on the outer periphery of the rod cap mounting position 321. The nut 34 fixes the piston rod cap 33 on the rod cap mounting position 321. The piston rod cap 33 is used to connect a driving mechanism, which drives the piston rod 32 to move through the driving mechanism, thereby driving the piston head 31 to approach and move away from the adapter 20. The driving mechanism can be a screw nut driving structure.

[0026] See also Figure 5As shown, the second rough-machined surface 121 is connected to the second fine-machined surface 122 via an arc surface 123 .

[0027] In this embodiment, the injection cavity 10, the adapter 20, and the piston assembly 30 are all made of stainless steel. Preferably, the injection cavity 10 is 304 stainless steel, the adapter 20 is 316L stainless steel, the piston assembly 30 is 303 stainless steel, and the piston rod sleeve 40 is made of POM.

[0028] The design emphasis of the present invention is: Mainly, an avoidance groove is provided at one end of the threaded section away from the abutment section, and an oil storage groove is recessed at the avoidance groove corresponding to the first cavity. The avoidance groove and the oil storage groove can allow grease at the piston head sealing ring to flow in, so as to prevent the grease from clogging the adapter when the piston head moves. In addition, a piston rod sleeve is provided on the piston rod outer sleeve. The piston rod sleeve is made of self-lubricating material, which can avoid direct friction between the piston rod and the injection cavity, effectively increasing the life of the syringe, and avoid noise caused by friction between the spring and the piston rod when the spring is compressed, so as to achieve better silencing effect. In addition, the provision of the first rough-machined surface and the second rough-machined surface can reduce the processing difficulty of the injection cavity and the piston rod sleeve. At the same time, the second rough-machined surface can reduce the friction area between the piston rod sleeve and the injection cavity, thereby further reducing the friction between the two and increasing the service life of the piston rod sleeve. The adapter is connected to the injection cavity by threads, which is simple to assemble and easy to maintain the piston head sealing ring and the piston rod sleeve.

[0029] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A high-precision piston syringe for pipetting, characterized in that: It includes an injection cavity, an adapter, a piston assembly, a piston rod sleeve and a spring, wherein the piston assembly includes a piston head and a piston rod connected to the piston head, and the injection cavity includes a first cavity and a second cavity which are connected in sequence; wherein: An adapter installation position is provided at one end of the first cavity away from the second cavity, the adapter installation position includes a first sealing ring groove and a threaded connection portion arranged in sequence, the adapter includes a main body and a mounting portion connected in sequence, an abutting section and a threaded section connected in sequence to the mounting portion, the abutting section covers the end of the first cavity away from the second cavity, an end of the threaded section close to the abutting section is provided with a second sealing ring groove corresponding to the first sealing ring groove, an adapter sealing ring is sandwiched between the first sealing ring groove and the second sealing ring groove, an avoidance groove is provided at one end of the threaded section away from the abutment section, and an oil storage groove is recessed at the first cavity corresponding to the avoidance groove; The piston head is located in the first cavity and can press against the end of the threaded section away from the abutting section. The outer periphery of the piston head is slidably connected to the first cavity through a piston head sealing ring. The piston rod sleeve is made of self-lubricating material. The piston rod sleeve is sleeved on the outer periphery of the piston rod. The end of the piston rod sleeve close to the piston head is provided with a pressing portion. The spring is sleeved on the outer periphery of the piston rod sleeve and clamped between the pressing portion and the end of the first cavity close to the second cavity. The elastic force of the spring presses the pressing portion against the piston head. A first rough-machined surface and a first fine-machined surface are sequentially arranged in the piston rod sleeve. The first fine-machined surface is arranged away from the piston head and fits the piston rod. A second rough-machined surface and a second fine-machined surface are sequentially arranged in the second cavity, the outer periphery of the piston rod sleeve is slidably connected to the second fine-machined surface, and one end of the piston rod away from the piston head extends out of the second cavity.

2. A high-precision piston syringe for pipetting according to claim 1, characterized in that: The main body is provided with a first channel and a second channel perpendicular to each other, the first channel is located at an end of the main body away from the mounting portion, the end of the second channel close to the first channel is connected to the first channel, the end of the second channel away from the first channel is exposed at the end of the threaded connection part, and the piston head can block the end of the second channel away from the first channel.

3. A high-precision piston syringe for pipetting according to claim 1, characterized in that: The oil storage tank includes a first oblique section, a horizontal section, and a second oblique section which are connected in sequence. The inclination of the second oblique section is smaller than that of the first oblique section. The second oblique section is arranged away from the adapter and is connected to the wall of the first cavity through an arc section.

4. A high-precision piston syringe for pipetting according to claim 1, characterized in that: A third sealing ring groove is provided on the outer periphery of the piston head, and the piston head sealing ring is sleeved in the third sealing ring groove. The end of the third sealing ring groove away from the piston rod is connected to the outer periphery of the piston head through a third oblique section, and the end of the third sealing ring groove close to the piston rod is connected to the outer periphery of the piston head through a fourth oblique section, and the inclination of the fourth oblique section is smaller than the inclination of the third oblique section.

5. A high-precision piston syringe for pipetting according to claim 1, characterized in that: A spring installation position is arranged at one end of the first cavity close to the second cavity. The spring installation position is arranged at the outer periphery of the second cavity. The spring sleeve is arranged between the pressing portion and the spring installation position.

6. A high-precision piston syringe for liquid transfer according to claim 1, characterized in that: The injection cavity is provided with an air hole penetrating the first cavity, and the air hole is arranged close to the second cavity.

7. A high-precision piston syringe for liquid transfer according to claim 1, characterized in that: The second rough-machined surface is connected to the second fine-machined surface through an arc surface.

8. A high-precision piston syringe for liquid transfer according to claim 1, characterized in that: A rod cap mounting position is arranged at one end of the piston rod away from the piston head, and a piston rod cap and a nut are arranged in sequence on the periphery of the rod cap mounting position, and the nut fixes the piston rod cap on the rod cap mounting position.

9. A high-precision piston syringe for liquid transfer according to claim 1, characterized in that: The injection cavity, adapter and piston assembly are all made of stainless steel.

10. A high-precision piston syringe for liquid transfer according to claim 9, characterized in that: The injection cavity is made of 304 stainless steel, the adapter is made of 316L stainless steel, the piston assembly is made of 303 stainless steel, and the piston rod sleeve is made of POM.

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