Split type piston sleeve pipette

Abstract

The utility model discloses a split type piston sleeve pipette. The split type piston sleeve pipette comprises a shell, a driving device, a piston, a first sleeve and a second sleeve, the first end of the piston is in transmission connection with a driving device, and the second end of the piston is inserted into the second sleeve from the first end of the second sleeve; the second sleeve is fixed on the shell; the first end of the first sleeve is detachably connected to the second end of the second sleeve in a sealed mode. The inner diameter of the first sleeve is matched with that of the second sleeve; and the second sleeve is used for limiting the first sleeve through a limiting structure. According to the split type piston sleeve pipette disclosed by the utility model, the processing difficulty of coaxiality when the first sleeve and the second sleeve are processed can be reduced, and the maintenance cost is low.

Description

Technical Field

[0001] The utility model belongs to the technical field of liquid transfer guns, and in particular relates to a split piston sleeve liquid transfer gun. Background Art

[0002] See also Figure 1 At present, the working principle of pipettes on the market is based on the air displacement method, and the liquid is sucked in and discharged through the displaced air. Each pipette has an internal piston 2 connected to the sleeve 1, and the volume of air directly pushed out by the piston 2 is equal to the volume of liquid sucked in. The factors that affect the performance of the pipette are mainly: 1. The relative sealing between the piston 2 and the sleeve 1; 2. The concentricity between the piston 2 and the sleeve 1 parts (parts tolerance). The better the concentricity, the more repeated movement of the piston 2, and the more stable the volume of air pushed out, that is, the better the stability of the pipette; 3. The dead volume between the piston 2 and the sleeve 1. The smaller the dead volume, the better. The dead volume refers to the volume of the gap between the piston 2 and the sleeve 1.

[0003] The structure of the existing pipette gun with air pressure detection function generally includes a sleeve 1, a piston 2 and an air pressure adapter 3. The piston 2 is inserted into the sleeve 1. The adapter 4 is welded on the upper part of the sleeve 1. The air pressure adapter 3 is connected to the adapter 4, and then the air pressure adapter 3 is connected to the air pressure sensor. The existing sleeve 1 is an integrated solution, and the air pressure adapter 3 is connected by welding the adapter 4. However, welding can easily cause the sleeve 1 to deform. The diameter of the sleeve 1 is generally about 5 or 6 mm. It is necessary to weld on such a small part and ensure that it will not deform, which makes the solution have very high requirements for the production and processing of parts. Moreover, the length of the integrated sleeve 1 is usually relatively long, and it is difficult to ensure its concentricity during processing. In addition, when liquid is sucked into the sleeve 1 by mistake, or when part of the sleeve 1 is damaged, the entire sleeve 1 needs to be replaced. The replacement process is more troublesome and the maintenance cost is high.

[0004] In addition, the connection structure between the piston 2 and the driving device of the existing pipette is a rigid connection, and the concentricity of the piston 2 and the sleeve 1 is completely dependent on the quality of parts processing and assembly, thus placing high requirements on the processing and assembly of parts. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the utility model aims to provide a split piston sleeve pipette gun, which can reduce the difficulty of processing the coaxiality of the first sleeve and the second sleeve during processing and has low maintenance costs.

[0006] In order to achieve the above-mentioned purpose, the utility model provides a split piston sleeve pipette, comprising a shell, a driving device, a piston, a first sleeve and a second sleeve; the first end of the piston is transmission connected to the driving device, and the second end of the piston is inserted into the second sleeve from the first end of the second sleeve; the second sleeve is fixed to the shell; the first end of the first sleeve is detachably sealed and connected to the second end of the second sleeve; the inner diameter of the first sleeve matches the inner diameter of the second sleeve; the second sleeve limits the first sleeve by a limiting structure.

[0007] As an embodiment, the second sleeve is integrally formed with a pneumatic adapter and a linear channel; the pneumatic adapter is connected to the linear channel; the linear channel is coaxially connected to the first sleeve; the inner diameter of the linear channel matches the inner diameter of the first sleeve.

[0008] As an embodiment, the end portion of the straight channel at the second end of the second sleeve is recessed to form a first sleeve mounting groove; the first end of the first sleeve is detachably inserted and fixed in the first sleeve mounting groove.

[0009] As an embodiment, the first end of the first sleeve and the outer wall depression corresponding to the first sleeve installation groove form a sealing ring installation groove, and the sealing ring is installed in the sealing ring installation groove; the first sleeve and the second sleeve are sealed and matched through the sealing ring.

[0010] As an embodiment, the limiting structure includes a flange edge, a radial limiting groove and a plurality of limiting bolts; the outer wall of the first end of the first sleeve extends outward adjacent to the second end of the second sleeve to form the flange edge; the end of the first sleeve mounting groove adjacent to the second end of the second sleeve is recessed to form the radial limiting groove; the flange edge is arranged in the radial limiting groove and the radial limiting groove radially limits the first sleeve through the flange edge; a plurality of screw holes are formed at the end of the second end of the second sleeve; the screw holes are located outside the radial limiting groove; the limiting bolt is screwed into the screw hole and the nut of the limiting bolt presses the flange edge and axially limits the flange edge.

[0011] As an embodiment, the second end of the first sleeve forms a suction nozzle connecting portion.

[0012] As an implementation manner, the air pressure adapter is connected to an air pressure sensor.

[0013] As an embodiment, the piston is connected to the driving device via a coaxiality adaptive fine-tuning mechanism.

[0014] As an embodiment, the coaxiality adaptive fine-tuning mechanism includes a driving block, an end plate, an elastic member and a guide structure; the driving block is connected to the driving device and forms a cylindrical space inside, and a through hole is formed at one end of the cylindrical space; the first end of the piston forms a hemispherical arc surface and extends into the cylindrical space from the through hole; the end plate is fixed to the periphery of the first end of the piston; the elastic member is pressed between the end plate and the inner wall of the driving block adjacent to the through hole; the elastic member presses the first end of the piston tightly against the inner wall of the driving block away from the through hole through the end plate; the guide structure is arranged in the second sleeve, and the guide structure guides the piston.

[0015] As an embodiment, the guide structure adopts a sleeve; the first end of the second sleeve is recessed to form a sleeve mounting groove; the sleeve is fixed in the sleeve mounting groove; the inner diameter of the sleeve matches the outer diameter of the piston; and the sleeve is coaxially arranged with the second sleeve; the piston is inserted in the sleeve and the second sleeve.

[0016] The utility model adopts the above technical solution, so that it has the following beneficial effects:

[0017] In the utility model, the one-piece sleeve is replaced by the split first sleeve and the second sleeve, firstly, the difficulty of processing the coaxiality of the first sleeve and the second sleeve is reduced; secondly, when the split first sleeve and the second sleeve are operated incorrectly and the liquid is sucked into the first sleeve, or when the first sleeve is partially damaged, only the first sleeve needs to be replaced, which greatly reduces the maintenance cost; in addition, the second sleeve is integrally formed to form the pneumatic adapter and the linear channel, which eliminates the problems of high difficulty in welding and easy deformation of the existing pneumatic adapter, reduces the processing difficulty of the pneumatic adapter, and also ensures the stability of the sleeve structure, and reduces the loss cost in the production process. The limiting structure is used to position the first sleeve in the axial and radial directions, and makes the replacement of the first sleeve very convenient. The adoption of the coaxiality adaptive fine-tuning mechanism makes it only have axial limiting between the piston and the drive block, and flexibility in other directions; it can greatly reduce the difficulty of installing the piston, reduce the connection accuracy requirements between the piston and the drive device, and ensure the coaxiality of the piston with the first sleeve and the second sleeve. The guide structure is used to limit the axial position of the piston to ensure the concentricity of the piston with the first sleeve and the second sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 It is a structural schematic diagram of an existing pipette;

[0020] Figure 2 This is an appearance diagram of a split piston-sleeve pipette gun according to an embodiment of the present application;

[0021] Figure 3 A schematic diagram of a portion of the internal structure of a split piston-sleeve pipette according to an embodiment of the present application;

[0022] Figure 4 This is a cross-sectional view of a split piston-sleeve pipette gun according to an embodiment of the present application;

[0023] Figure 5 for Figure 4 A partial enlarged view of the middle A area;

[0024] Figure 6 This is a schematic diagram of the structure of a split piston sleeve according to an embodiment of the present application.

[0025] Description of Figure Numbers:

[0026] Figure 1 :

[0027] 1- sleeve;

[0028] 2-Piston;

[0029] 3-Air pressure adapter;

[0030] 4-Transfer part.

[0031] Figure 2 to Figure 6 :

[0032] 1- housing;

[0033] 2-Piston;

[0034] 3- first sleeve;

[0035] 31-seal ring installation groove; 32-flange edge; 33-sucking nozzle connection part;

[0036] 4- second sleeve;

[0037] 41-air pressure adapter; 42-linear channel; 43-first sleeve mounting groove; 44-radial limiting groove; 45-limiting bolt;

[0038] 46-sleeve mounting groove; 47-sealing structure; 48-guide structure;

[0039] 5- Sealing ring;

[0040] 6-Coaxiality adaptive fine-tuning mechanism;

[0041] 61-driving block; 62-end piece; 63-elastic member; 64-shaft sleeve. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0043] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "center", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc., are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0044] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "setting", "connection", "connection" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] Example 1

[0046] See also Figure 2 to Figure 5A split piston sleeve pipette gun according to a first embodiment of the utility model comprises a housing 1, a driving device, a piston 2, a first sleeve 3 and a second sleeve 4; the first end of the piston 2 is drivingly connected to the driving device, and the second end of the piston 2 is inserted into the second sleeve 4 from the first end of the second sleeve 4; the second sleeve 4 is fixed to the housing 1; the first end of the first sleeve 3 is detachably sealed and connected to the second end of the second sleeve 4; the inner diameter of the first sleeve 3 matches the inner diameter of the second sleeve 4; the second sleeve 4 limits the first sleeve 3 by a limiting structure.

[0047] In the utility model, the one-piece sleeve is replaced with a split first sleeve 3 and a second sleeve 4. Firstly, the length of a single sleeve is shortened, thereby reducing the difficulty of machining the coaxiality of the first sleeve 3 and the second sleeve 4. Secondly, when the split first sleeve 3 and the second sleeve 4 are operated incorrectly and liquid is sucked into the first sleeve 3, or when part of the first sleeve 3 is damaged, only the first sleeve 3 needs to be replaced, thereby greatly reducing the maintenance cost.

[0048] As an embodiment, the second sleeve 4 is integrally formed with a pneumatic adapter 41 and a linear channel 42; the pneumatic adapter 41 is connected to the linear channel 42; the linear channel 42 is coaxially connected to the first sleeve 3; the inner diameter of the linear channel 42 matches the inner diameter of the first sleeve 3.

[0049] The second sleeve 4 is integrally formed to form the air pressure adapter 41 and the straight channel 42, and machining is used instead of welding, thereby eliminating the problems of high difficulty in welding the existing air pressure adapter 41 and easy deformation of the sleeve, reducing the difficulty in processing the air pressure adapter 41, while also ensuring the stability of the sleeve structure, facilitating the guarantee of part size, and reducing loss costs during the production process.

[0050] As an implementation manner, the end portion of the linear channel 42 at the second end of the second sleeve 4 is recessed to form a first sleeve mounting groove 43 ; the first end of the first sleeve 3 is detachably inserted and fixed in the first sleeve mounting groove 43 .

[0051] The first sleeve installation groove 43 provides space for the installation of the first end of the first sleeve 3 , and provides a basis for ensuring that the inner diameter of the first sleeve 3 matches the inner diameter of the linear channel 42 and that the first sleeve 3 and the linear channel 42 are coaxially connected.

[0052] As an embodiment, the first end of the first sleeve 3 and the outer wall depression corresponding to the first sleeve installation groove 43 form a sealing ring installation groove 31, and the sealing ring 5 is installed in the sealing ring installation groove 31; the first sleeve 3 and the second sleeve 4 are sealed together through the sealing ring 5.

[0053] The use of the sealing ring 5 ensures the sealing fit between the first sleeve 3 and the second sleeve 4 .

[0054] As an embodiment, the limiting structure includes a flange edge 32, a radial limiting groove 44 and a plurality of limiting bolts 45; the outer wall of the first end of the first sleeve 3 extends outward adjacent to the second end of the second sleeve 4 to form the flange edge 32; the first sleeve mounting groove 43 is recessed adjacent to the end of the second end of the second sleeve 4 to form the radial limiting groove 44; the flange edge 32 is arranged in the radial limiting groove 44 and the radial limiting groove 44 radially limits the first sleeve 3 through the flange edge 32; a plurality of screw holes are formed at the end of the second end of the second sleeve 4; the screw holes are located on the outside of the radial limiting groove 44; the limiting bolt 45 is screwed into the screw hole and the nut of the limiting bolt 45 presses the flange edge 32 and axially limits the flange edge 32.

[0055] The limiting structure is used to position the first sleeve 3 in the axial and radial directions, and makes the replacement of the first sleeve 3 very convenient. The radial limiting of the first sleeve 3 is achieved by the cooperation of the radial limiting groove 44 of the flange 32; the flange 32 is pressed by the nut of the limiting bolt 45 and the flange 32 is axially limited. The thickness of the flange 32 needs to be greater than or equal to the axial depth of the radial limiting groove 44.

[0056] In case of misoperation, where liquid is sucked into the first sleeve 3 or the first sleeve 3 is damaged, it is only necessary to remove the limit bolt 45 and then pull out the first sleeve 3 for replacement, which is very convenient.

[0057] As an implementation manner, the second end of the first sleeve 3 forms a suction nozzle connecting portion 33 .

[0058] The nozzle connection portion 33 is used to connect a disposable nozzle during use.

[0059] As an implementation manner, the air pressure adapter 41 is connected to an air pressure sensor.

[0060] The air pressure sensor is used to monitor the air pressure intensity in the second sleeve 4 through the air pressure adapter 41 .

[0061] Example 2

[0062] See also Figure 6 The structure of a split piston sleeve pipette gun in the second embodiment of the utility model is basically the same as that in the first embodiment, except that the piston 2 is connected to the driving device through a coaxiality adaptive fine-tuning mechanism 6.

[0063] As an embodiment, the coaxiality adaptive fine-tuning mechanism 6 includes a driving block 61, an end plate 62, an elastic member 63 and a guide structure; the driving block 61 is connected to the driving device and forms a cylindrical space inside, and one end of the cylindrical space forms a through hole; the first end of the piston 2 forms a hemispherical arc surface and extends from the through hole into the cylindrical space; the end plate 62 is fixed to the periphery of the first end of the piston 2; the elastic member 63 is pressed between the end plate 62 and the inner wall of the driving block 61 adjacent to the through hole; the elastic member 63 presses the first end of the piston 2 tightly against the inner wall of the driving block 61 away from the through hole through the end plate 62; the guide structure is arranged in the second sleeve 4, and the guide structure guides the piston 2.

[0064] In this embodiment, the elastic member 63 is a spring. The elastic force of the elastic member 63 needs to ensure that during use, the first end of the piston 2 is pressed tightly against the inner wall of the driving block 61 away from the through hole, so as to ensure the stability of the liquid transfer during use.

[0065] As an embodiment, the guide structure adopts a sleeve 64; the first end of the second sleeve 4 is recessed to form a sleeve mounting groove 46; the sleeve 64 is fixed in the sleeve mounting groove 46; the inner diameter of the sleeve 64 matches the outer diameter of the piston 2; and the sleeve 64 is coaxially arranged with the second sleeve 4; the piston 2 is inserted into the sleeve 64 and the second sleeve 4.

[0066] The use of the coaxiality adaptive fine-tuning mechanism 6 ensures that there is only axial limitation between the piston 2 and the driving block 61, and flexibility is present in other directions; different from the existing rigid connection structure, it can greatly reduce the difficulty of installing the piston 2, reduce the connection accuracy requirements between the piston 2 and the driving device, and ensure the coaxiality of the piston 2 and the first sleeve 3 and the second sleeve 4.

[0067] The guide structure is used to limit the axial position of the piston 2 to ensure the concentricity of the piston 2 and the first sleeve 3 and the second sleeve 4.

[0068] Example 3

[0069] See also Figure 1 to Figure 5 The structure of a split piston sleeve pipette gun according to the third embodiment of the present invention is basically the same as that of the first embodiment, except that the second sleeve 4 forms a straight channel 42 but does not form a pneumatic adapter 41.

[0070] The split piston sleeve pipette at this time does not include an air pressure detection function, but still has the advantages of a split sleeve: first, the length of a single sleeve is shortened, reducing the difficulty of coaxiality processing of the first sleeve 3 and the second sleeve 4; secondly, when the split first sleeve 3 and the second sleeve 4 are operated incorrectly and the liquid is sucked into the first sleeve 3, or when part of the first sleeve 3 is damaged, only the first sleeve 3 needs to be replaced, which greatly reduces maintenance costs.

[0071] Example 4

[0072] A split piston sleeve pipette gun according to embodiment 4 of the utility model has a structure that is basically the same as that of embodiment 1, with the difference that an external thread is formed on the outer wall of the first sleeve 3; an internal thread matching the external thread is formed in the mounting groove of the first sleeve 3; the limiting structure includes an external thread and an internal thread; the first sleeve 3 is threadedly connected to the mounting groove of the first sleeve 3 through the external thread and the internal thread; and a seal is arranged between the first sleeve 3 and the second sleeve 4.

[0073] The threaded structure can realize the positioning and detachability of the first sleeve 3 and the second sleeve 4, and the sealing member can realize the sealing cooperation between the first sleeve and the second sleeve.

[0074] In other embodiments, other existing limiting structures that can achieve detachable and sealed connection between two pipes may also be used.

[0075] Example 5

[0076] A split piston sleeve pipette gun according to embodiment 5 of the utility model has a structure that is basically the same as that of embodiment 2, with the difference that the guide structure includes a plurality of arc-shaped segments; the first end of the second sleeve 4 is recessed at intervals along the circumferential direction to form a plurality of guide member mounting grooves; the arc-shaped segments are fixed in the guide member mounting grooves; the inner diameter of the arc-shaped segments matches the outer diameter of the piston 2; and the arc-shaped segments are all coaxially arranged with the second sleeve 4; the piston 2 is inserted between the arc-shaped segments and in the second sleeve 4.

[0077] The structure of the guide structure is not limited to the shaft sleeve 64 and the pipe sheet. In other embodiments, other structures that can ensure the concentricity of the piston 2 and the first sleeve 3 and the second sleeve 4 can also be used.

[0078] Example 6

[0079] The structure of the split piston sleeve liquid transfer gun of the sixth embodiment of the utility model is basically the same as that of the first embodiment, except that a sealing structure 47 and a guide structure 48 are provided at the first end of the second sleeve 4; the sealing structure can be a pan seal, an O-ring or other existing seals. The guide structure can be a shaft sleeve.

[0080] The use of the sealing structure 47 ensures the sealing between the piston 2 and the second sleeve 4. The guide structure 48 is used to ensure the concentricity of the inner diameter of the piston 2 and the second sleeve 4.

[0081] The utility model is described in detail above in conjunction with the embodiments of the drawings. A person skilled in the art can make various variations of the utility model according to the above description. Therefore, some details in the embodiments should not constitute a limitation of the utility model, and the scope of protection of the utility model shall be defined by the scope of the attached claims.

Claims

1. A split piston sleeve pipette, characterized in that: It includes a shell, a driving device, a piston, a first sleeve and a second sleeve; the first end of the piston is drivingly connected to the driving device, and the second end of the piston is inserted into the second sleeve from the first end of the second sleeve; the second sleeve is fixed to the shell; the first end of the first sleeve is detachably sealed and connected to the second end of the second sleeve; the inner diameter of the first sleeve matches the inner diameter of the second sleeve; the second sleeve limits the first sleeve by a limiting structure.

2. The split piston sleeve pipette according to claim 1, characterized in that: The second sleeve is integrally formed to form a pneumatic adapter and a linear channel; the pneumatic adapter is connected to the linear channel; the linear channel is coaxially connected to the first sleeve; the inner diameter of the linear channel matches the inner diameter of the first sleeve.

3. The split piston sleeve pipette according to claim 2, characterized in that: The end of the linear channel at the second end of the second sleeve is recessed to form a first sleeve installation groove; the first end of the first sleeve is detachably inserted and fixed in the first sleeve installation groove.

4. The split piston sleeve pipette according to claim 3, characterized in that: The first end of the first sleeve and the outer wall depression corresponding to the first sleeve installation groove form a sealing ring installation groove, and the sealing ring is installed in the sealing ring installation groove; the first sleeve and the second sleeve are sealed and matched through the sealing ring.

5. The split piston sleeve pipette according to claim 3, characterized in that: The limiting structure includes a flange edge, a radial limiting groove and a plurality of limiting bolts; the outer wall of the first end of the first sleeve extends outward adjacent to the second end of the second sleeve to form the flange edge; the end of the first sleeve mounting groove adjacent to the second end of the second sleeve is recessed to form the radial limiting groove; the flange edge is arranged in the radial limiting groove and the radial limiting groove radially limits the first sleeve through the flange edge; a plurality of screw holes are formed at the end of the second end of the second sleeve; the screw holes are located outside the radial limiting groove; the limiting bolt is screwed into the screw hole and the nut of the limiting bolt presses the flange edge and axially limits the flange edge.

6. The split piston sleeve pipette according to claim 1, characterized in that: The second end of the first sleeve forms a suction nozzle connecting portion.

7. The split piston sleeve pipette according to claim 2, characterized in that: The air pressure adapter is connected to an air pressure sensor.

8. The split piston sleeve pipette according to claim 1, characterized in that: The piston is connected to the driving device via a coaxiality adaptive fine-tuning mechanism.

9. The split piston sleeve pipette according to claim 8, characterized in that: The coaxiality adaptive fine-tuning mechanism includes a driving block, an end plate, an elastic member and a guiding structure; the driving block is connected to the driving device and forms a cylindrical space inside, and a through hole is formed at one end of the cylindrical space; the first end of the piston forms a hemispherical arc surface and extends into the cylindrical space from the through hole; the end plate is fixed to the periphery of the first end of the piston; the elastic member is pressed between the end plate and the inner wall of the driving block adjacent to the through hole; the elastic member presses the first end of the piston tightly against the inner wall of the driving block away from the through hole through the end plate; the guiding structure is arranged in the second sleeve, and the guiding structure guides the piston.

10. The split piston sleeve pipette according to claim 9, characterized in that: The guide structure adopts a sleeve; the first end of the second sleeve is recessed to form a sleeve mounting groove; the sleeve is fixed in the sleeve mounting groove; the inner diameter of the sleeve matches the outer diameter of the piston; and the sleeve is coaxially arranged with the second sleeve; the piston is inserted in the sleeve and the second sleeve.

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