Anti-pollution pipettor

Abstract

The invention provides an anti-pollution pipettor. The anti-pollution pipettor comprises a gun head and a body, a liquid suction nozzle is arranged at the lower part of the body, the locking part comprises an outer cylinder, a locking cylinder and a locking piece, the locking piece comprises a locking bundle and a fixed seat, a through hole matched with the lower end of the liquid suction nozzle is formed in the fixed seat, the gun head comprises a gun head body and a thin tube, and one end of the thin tube is concentrically fixed at the front end of the gun head body. During use, the locking bundle locks the gun head body, so that the gun head is prevented from falling off, firm connection between the gun head and the body is guaranteed, reagent pollution caused by falling off of the gun head is avoided, liquid is fed through the thin tube, bubbles generated by liquid feeding are reduced, and the problems that reagent solution is sucked into the gun body, cleaning is difficult, complete cleaning cannot be achieved, and cross contamination is caused are further avoided. The body is kept clean, internal corrosion is avoided, and the service life of the body is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of pipettes, in particular to an anti-pollution pipette. Background Art

[0002] A pipette, also known as a pipette gun, is a measuring tool used to accurately transfer trace amounts of liquid. Since its introduction, it has been widely used in many fields due to its simple structure, ease of use, and high precision.

[0003] The current pipettes mainly have the following technical problems: 1. The existing pipette tip is connected to the pipette by interference fit, and the connection between the pipette tip and the pipette is not firm, so it is easy to slip and cause the reagent to be contaminated by the dropped pipette tip; 2. The internal structure of the gun head is simple, and there is no device to prevent the inhalation of bubbles or the contamination of the internal pipeline of the pipette body caused by the inhalation of bubbles, etc. This causes cross contamination when aspirating different liquid samples, and it is difficult to completely clean the inside of the gun body. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings in the prior art and to propose an anti-pollution pipette.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A contamination-proof pipette comprises a pipette tip and a body; The lower part of the body is provided with a liquid suction nozzle, and also includes a locking part, and the locking part includes an outer tube, a locking tube and a locking piece, the upper end of the outer tube is fixed on the body, the outer tube is sleeved on the outside of the liquid suction nozzle, the length of the outer tube is greater than the length of the liquid suction nozzle, the locking tube is concentrically fixed to the lower end of the outer tube, the locking tube is provided with a locking hole, and the locking hole is truncated; the locking piece includes a locking bundle and a fixing seat, the locking bundle is fixed to one end of the fixing seat, a plurality of the locking bundles are equidistantly arranged along the circumference, the fixing seat is provided with a through hole matched with the lower end of the liquid suction nozzle, the locking piece is arranged in the outer tube, and the locking bundle is located in the locking hole; The diameter of the fixing seat is smaller than the inner diameter of the outer cylinder and larger than the diameter of the upper end of the locking hole; The gun tip comprises a gun tip body and a thin tube. The front end of the gun tip body is concentrically fixed with one end of the thin tube, and the thin tube is extended along the length direction of the gun tip body.

[0006] Furthermore, the locking beam is connected to a fixing ball at one end away from the fixing seat, and a locking groove is provided on the gun head body. The locking groove is an annular groove, and the locking groove is arranged close to the tail end of the gun head body. The distance between the locking groove and the tail end of the gun head body is equal to the distance between the fixing ball and the lower end surface of the fixing seat.

[0007] Furthermore, the shape of the through hole is the same as the shape of the lower end of the liquid suction nozzle, an annular groove is provided in the through hole, and a sealing ring is embedded in the annular groove.

[0008] Furthermore, an annular sealing gasket is provided on the side of the fixing seat facing the locking bundle, and the sealing gasket is arranged on the fixing seat on the inner side of the locking bundle. The sealing gasket is arranged concentrically with the locking bundle, and the outer diameter of the sealing gasket is smaller than the inner diameter of the locking bundle, and the inner diameter of the sealing gasket is larger than the diameter of the through hole of the end face of the fixing seat facing the locking bundle.

[0009] Furthermore, the gun tip body includes a cavity main section and a buffer section, wherein the buffer section is located at the rear end of the gun tip body, the buffer section has a buffer cavity, and the cavity main section has a accommodating cavity, the buffer cavity and the accommodating cavity are connected through a connecting cavity, the diameter of the connecting cavity is smaller than the diameter of the accommodating cavity, and the diameter of the buffer cavity exceeds the diameter of the accommodating cavity.

[0010] Furthermore, a circular hole is provided on the end face of the tail end of the gun head body, and the upper end of the short tube is concentrically connected to the circular hole. The lower end of the short tube extends into the buffer cavity, and a fixed cover is fixed to the outside of the short tube. The fixed cover includes a cover plate and a cover wall. The short tube passes through the cover plate and is connected and fixed to the cover plate. The cover plate is also provided with a first air vent. The upper end face of the cover wall is connected to the cover plate, and a film is fixed to the lower end face of the cover wall. The film is hemispherically arched, and the lower end of the short tube is blocked when the film is arched upward.

[0011] Furthermore, the film is a rubber film, and an annular ridge is provided on the end surface of the tail end of the gun head body. The annular ridge is located outside the circular hole, and the annular ridge is concentrically arranged with the circular hole.

[0012] Furthermore, a branch cavity is also provided in the body, an open groove is provided on the side of the body, a membrane cavity groove is provided on one side groove wall of the open groove, a flexible membrane is fixed on the open end of the membrane cavity groove, a through hole is provided on the groove wall on the other side of the open groove to connect to the bottom of the suction cavity of the body, a sealing plug is fixed on the flexible membrane, and the sealing plug seals the through hole; the inner cavity of the liquid suction nozzle includes a Venturi section, the Venturi section includes a contraction section, a throat and a diffusion section, the branch cavity includes a first branch cavity, a second branch cavity and a third branch cavity, one end of the first branch cavity is connected to the throat, the other end of the first branch cavity is connected to one end of the second branch cavity and the third branch cavity, the other end of the third branch cavity is connected to the membrane cavity groove, the other end of the second branch cavity extends to connect to the inner cavity of the liquid suction nozzle and is connected to the upper end of the inner tube, the inner tube extends downward along the length direction of the liquid suction nozzle, and when the gun head body is fixed, the lower end of the inner tube extends from the lower end of the short tube and is flush with the lower end of the cover wall.

[0013] Furthermore, a partition is provided in the through hole, a second air vent is provided on the partition, a first through hole is provided in the middle of the partition, the upper end face of the sealing plug fixes the lower end of a short rod, the short rod passes through the first through hole, the outer side surface of the short rod slides with the hole wall of the first through hole, a first spring is sleeved on the outer side of the short rod, a first pressure plate is fixed on the upper end of the short rod, the diameter of the first pressure plate is smaller than the diameter of the through hole, and the upper and lower ends of the first spring connect the first pressure plate and the partition.

[0014] Furthermore, a detachable push arm is also provided in the body, and the detachable push arm includes a push arm, a ring and a telescopic spring. An installation cavity is provided in the body, and the installation cavity includes a spring cavity. The push arm is arranged in the installation cavity, and the lower end of the push arm is connected to the ring, and the ring is sleeved on the outside of the suction nozzle. The upper end of the push arm passes through the outside of the body and is connected to a fixed press plate; the telescopic spring is arranged in the spring cavity, and the telescopic spring is sleeved outside the push arm. The lower end of the telescopic spring is connected to the lower end of the spring cavity, and the upper end of the telescopic spring is connected to the second pressure plate, and the second pressure plate is fixed on the push arm.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention is designed with a locking part, which includes an outer tube, a locking tube and a locking member, and the locking member includes a locking bundle and a fixing seat. A through hole is designed on the fixing seat. When in use, the tail end of the gun tip is placed in the locking bundle, and the fixing seat is pressed to move toward one side of the liquid suction nozzle, driving the locking member to move toward the side of the liquid suction nozzle. The liquid suction nozzle is inserted into the through hole and has an interference fit with the through hole. The locking bundle is squeezed by the locking hole and locks the gun tip body inward to prevent the gun tip from falling off, ensuring that the gun tip and the body are firmly connected. After the two are connected, they are not easy to detach, which prevents the gun tip from falling off during use and contaminating the reagent, interrupting the test, or causing inaccurate tests. The present invention no longer uses the liquid suction nozzle to connect the gun tip in an interference fit manner, and the liquid suction nozzle is no longer inserted into the gun tip, which prevents the liquid suction nozzle from contacting the reagent in the gun tip and prevents contamination. (2) The front end of the gun head body of the present invention is concentrically fixed with a capillary tube, through which liquid is introduced, bubbles generated by the liquid introduction are reduced. The capillary tube can also prevent leakage at the top of the gun head, ensuring more accurate liquid introduction. (3) The gun head body of the present invention includes a cavity main body section and a buffer section, which prevents the inhalation of bubbles from causing liquid overflow and avoids the inhalation of reagent solution into the body to cause pollution. A short tube, a fixed cover and a film are designed in the buffer cavity of the buffer section. When the buffer cavity contains reagent solution, the buoyancy of the solution drives the film to arch upward, blocking the lower end of the short tube, and no longer continues to inhale to form a negative pressure to absorb the reagent solution, preventing the solution from continuing to overflow into the buffer cavity, and flowing out from the circular hole at the top of the buffer cavity to contact the body, avoiding contamination of the body, preventing the reagent solution from being inhaled into the interior of the gun body, avoiding internal corrosion, and extending the service life of the body. It eliminates the waste of time caused by cleaning the gun body and improves the use efficiency. (4) The body of the present invention is also provided with a branch cavity, the inner cavity of the liquid suction nozzle is provided with a Venturi section, and a membrane cavity groove is designed. The opening of the membrane cavity groove fixes a flexible membrane, and the flexible membrane fixes a sealing plug to seal the through hole. The through hole is connected to the bottom of the suction cavity of the body. The branch cavity is connected to the throat of the Venturi section. When the liquid enters the buffer cavity, the buoyancy causes the film to arch upward and block the inner tube. The inner tube is connected to the branch cavity, and the inner tube cannot continue to inhale. The Venturi effect is used to absorb the gas in the membrane cavity groove, so that a negative pressure is formed in the membrane cavity groove. Under the action of the negative pressure, the sealing plug is driven to move downward and disengage from the through hole. Since the through hole is directly connected to the air, it is easier to inhale, and the suction cavity is aired from the through hole, and the liquid is no longer sucked in through the liquid suction nozzle, so as to avoid the reagent solution being sucked into the body through the liquid suction nozzle, which makes it difficult to clean and cannot be completely cleaned, causing cross contamination. Ensure the cleanliness of the body, avoid reagent contamination and corrosion, and extend the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 is an enlarged view of a part a of Example 1 of the present invention; Figure 3It is a schematic diagram of the three-dimensional structure of the locking member according to Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the structure of the gun tip according to Embodiment 1 of the present invention; Figure 5 It is a schematic diagram of the three-dimensional structure of the short tube and the fixed cover of Example 1 of the present invention; Figure 6 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 7 It is an enlarged view of part b of Example 2 of the present invention; Figure 8 It is an enlarged view of part c of Example 2 of the present invention. DETAILED DESCRIPTION

[0017] In order to provide a further understanding of the purpose, structure, features, and functions of the present invention, the following detailed description is given in conjunction with the embodiments. Example

[0018] like Figure 1 , Figure 2 Figure 3 , Figure 4 and Figure 5 , a contamination-proof pipette, comprising a gun tip 100 and a body 200; the body comprises a suction chamber 201, which is based on an air piston design and is used to generate negative pressure to suck liquid into the gun tip 100 to achieve the removal of reagents.

[0019] The lower part of the body 200 is provided with a suction nozzle 210, and also includes a locking part 300, the locking part 300 includes an outer tube 310, a locking tube 320 and a locking member 330, the upper end of the outer tube 310 is fixed on the body 200, the outer tube 310 is sleeved on the outer side of the suction nozzle 210, the length of the outer tube 310 is greater than the length of the suction nozzle 210, the locking tube 320 is concentrically fixed to the lower end of the outer tube 310, and the locking tube 320 is provided with a locking hole 321, the locking hole 321 is truncated cone-shaped; the diameter of the locking hole 321 gradually increases from top to bottom, the locking member 330 includes a locking bundle 331 and a fixing seat 332, the locking bundle 331 is fixed at one end of the fixing seat 332, a plurality of the locking bundles 331 are arranged equidistantly along the circumference, the fixing seat 332 is provided with a through hole 333 that cooperates with the lower end of the suction nozzle, the locking member 330 is arranged in the outer tube 310, and the locking bundle 331 is located in the locking hole 321.

[0020] The diameter of the fixing seat 332 is smaller than the inner diameter of the outer cylinder 310 and larger than the diameter of the upper end of the locking hole 321, so that the locking member 330 can be stuck in the outer cylinder 310 and will not fall off and contaminate the reagent, thereby avoiding the loss of pipette parts.

[0021] The gun tip 100 includes a gun tip body 110 and a capillary 120. The front end of the gun tip body 110 is concentrically fixed with one end of the capillary 120. The capillary 120 is extended along the length direction of the gun tip body 110. The inner diameter of the capillary 120 is 0.1-1 mm. Liquid is introduced through the capillary 120 to reduce bubbles generated by the liquid introduction. The capillary 120 can also prevent liquid leakage at the top end of the gun tip, ensuring more accurate liquid introduction.

[0022] When in use, use the gun tip box to arrange the gun tips, take out the body, put the tail end of the gun tip 100 into the locking bundle 331, press the fixing seat 332 to move toward the side of the pipette nozzle 210, drive the locking piece 330 to move toward the side of the pipette nozzle 210, insert the pipette nozzle 210 into the through hole 333, and have an interference fit with the through hole 333, the locking bundle 331 is squeezed by the locking hole 321, and locks the gun tip body 110 inward to prevent the gun tip 100 from falling off, ensuring that the gun tip 100 is firmly connected to the body 200, and the two are not easy to detach after being connected, to prevent the gun tip 100 from falling off and contaminating the reagent during use, interrupting the test, or causing inaccurate tests.

[0023] The end of the locking beam 331 away from the fixing seat is connected to the fixing ball 334. The gun head body 110 is provided with a locking groove 111, which is an annular groove. The locking groove 111 is arranged near the tail end of the gun head body 110, and the distance between the locking groove 111 and the tail end of the gun head body 110 is equal to the distance between the fixing ball 334 and the lower end surface of the fixing seat 332. When locking the gun head 100, the fixing ball 334 can be embedded in the annular groove 111, and the locking beam 331 is connected to the fixing ball 334 to prevent the gun head from falling. The distance between the locking groove 111 and the tail end of the gun head body 110 is set to ensure that when the gun head 100 is fixed, the tail end contacts the fixing seat 332 to achieve sealing, so as to ensure that the gun head 100 can smoothly absorb liquid.

[0024] The shape of the through hole 333 is the same as the shape of the lower end of the liquid suction nozzle 210. An annular groove 335 is provided in the through hole 333. A sealing ring 336 is embedded in the annular groove 335. There is at least one sealing ring 336. It is ensured that the through hole 333 and the liquid suction nozzle 210 can be sealed and connected tightly to avoid falling off.

[0025] The side of the fixing seat 332 facing the locking bundle 331 is provided with an annular sealing gasket 337, the sealing gasket 337 is arranged on the fixing seat 332 on the inner side of the locking bundle, the sealing gasket 337 is arranged concentrically with the locking bundle 331, the outer diameter of the sealing gasket 337 is smaller than the inner diameter of the locking bundle 331, the inner diameter of the sealing gasket 337 is larger than the diameter of the through hole of the end face of the fixing seat facing the locking bundle 331, the diameter of the through hole 333 of the lower end face of the fixing seat 332 is the same as the inner diameter of the liquid suction nozzle 210, ensuring that the gas can flow smoothly after the connection. Through the design of the sealing gasket 337, it is ensured that the tail end of the gun head body 110 is in contact with the sealing gasket 337, the sealing performance is better, and air leakage is prevented, so that the gun head 100 can smoothly absorb liquid when connected with the body 200 for use, realize pipetting, and ensure the accuracy of pipetting of the pipette.

[0026] The gun head body 110 includes a cavity main body section 112 and a buffer section 113, wherein the buffer section is located at the rear end of the gun head body 110, the buffer section 113 has a buffer cavity 130, and the cavity main body section 112 has a receiving cavity 140, wherein the buffer cavity 130 is connected to the receiving cavity 140 through a connecting cavity 150, wherein the diameter of the connecting cavity 150 is smaller than the diameter of the receiving cavity 140, and the diameter of the buffer cavity 130 exceeds the diameter of the receiving cavity 140. The sum of the volume of the receiving cavity 140 and the volume of the buffer cavity 130 is greater than the volume of the suction cavity 201 of the body, and the design of the buffer cavity 130 prevents the liquid from overflowing due to the suction of bubbles, and the present invention no longer uses an interference fit to connect the gun head 100, and the liquid suction nozzle 210 is no longer inserted into the gun head 100, thereby avoiding the contact between the liquid suction nozzle and the reagent in the gun head and preventing contamination.

[0027] Combination Figure 4 and Figure 5A circular hole 115 is provided on the end face of the tail end of the gun head body 110, and the circular hole is concentrically connected to the upper end of a short tube 160, and the lower end of the short tube 160 extends into the buffer chamber 130. A fixed cover 170 is also fixed to the outside of the short tube 160, and the fixed cover 170 includes a cover plate 171 and a cover wall 172. The short tube 160 passes through the cover plate 171 and is connected and fixed to the cover plate 171. A first air vent 173 is also provided on the cover plate 171. The upper end face of the cover wall 172 is connected to the cover plate 171, and a film 174 is fixed to the lower end face of the cover wall 172. The film 174 is hemispherically arched. In a normal state, the film 174 arches downward, and when the film 174 arches upward, it blocks the lower end of the short tube 160. During normal use, the main body 200 inhales air, and the gas in the gun head main body 110 enters the fixed cover 170 from the first air hole 173 on the cover plate, and enters the main body through the short tube 160, forming a negative pressure in the gun head main body 110, absorbing liquid, and realizing normal use. When the buffer chamber 130 contains a reagent solution, the buoyancy of the solution drives the film 174 to arch upward, blocking the lower end of the short tube 160, and no longer continues to inhale air to form a negative pressure to absorb the reagent solution, preventing the solution from continuing to overflow into the buffer chamber, and flowing out from the circular hole 115 at the top of the buffer chamber 130 to contact the main body, avoiding contamination of the main body, preventing the reagent solution from being sucked into the interior of the gun body, avoiding internal corrosion, and extending the service life of the main body. It eliminates the waste of time caused by cleaning the gun body and improves the use efficiency.

[0028] The film 174 is a rubber film, which has low cost, certain acid and alkali corrosion resistance, softness and variability, and can be realized under the action of liquid, the short tube is blocked by the upper arch, the short tube 160 is sealed, and the overflow contamination of the gun body is avoided. During production, the tail end and the gun head body can be injection molded in batches respectively, the tail end is integrated with the short tube 160 and the fixed cover 170, the film 174 is connected to the cover wall 172 of the fixed cover by thermoplasticity, and then the gun head body is connected to the tail end. An annular convex ridge 114 is also provided on the end face of the tail end of the gun head body 110, and the annular convex ridge 114 is located outside the circular hole, and the annular convex ridge 114 is concentrically arranged with the circular hole 115. The cross section of the annular convex ridge 114 is semicircular, and through the annular convex ridge 114, it is easier for the surface of the sealing gasket to contact, ensure the sealing, prevent air leakage, and ensure the smooth progress of liquid absorption.

[0029] The main body 200 is also provided with a detachable push arm 400, and the detachable push arm 400 includes a push arm 410, a ring 420 and a telescopic spring 430. The main body 200 is provided with a mounting cavity 202, and the mounting cavity 202 includes a spring cavity. The push arm 410 is arranged in the mounting cavity, and the lower end of the push arm 410 is connected to the ring 420, and the ring 420 is sleeved on the outside of the suction nozzle 210. The upper end of the push arm 410 passes through the outside of the main body 100 and is connected to a fixed pressing plate 440; the telescopic spring 430 is arranged in the spring cavity, and the telescopic spring 430 is sleeved outside the push arm 410. The lower end of the telescopic spring 430 is connected to the lower end of the spring cavity, and the upper end of the telescopic spring 430 is connected to the second pressing plate 450, and the second pressing plate 450 is fixed on the push arm 410. The length of the telescopic spring 430 is greater than the distance between the lower end of the collar 420 and the lower end of the liquid suction nozzle 210, ensuring that the pressing plate 440 is pressed to squeeze the telescopic spring 430 to contract, and the lower end of the collar 420 can push the fixing seat 332 to move to the end away from the liquid suction nozzle 210, so that the fixing seat 332 is separated from the liquid suction nozzle 210, and the locking beam 331 is no longer squeezed by the locking hole 321, and is separated from the gun head body 110, so that the gun head 100 is separated from the body. After giving up pressing the pressing plate 440, the spring returns to its original shape, and the collar returns to its original position, which is convenient for installing the gun head next time. Example

[0030] like Figure 6 , Figure 7 and Figure 8, other structures are the same as those in Example 1, except that a branch cavity 220 is further provided in the body 200, an open groove 230 is provided on the side of the body 200, a membrane cavity groove 231 is provided on one side of the groove wall of the open groove 230, a flexible membrane 240 is fixed to the open end of the membrane cavity groove 231, a through hole 232 is provided on the groove wall on the other side of the open groove 230 to connect to the bottom of the suction cavity 201 of the body, a sealing plug 250 is fixed on the flexible membrane 240, and the sealing plug 250 can be connected and fixed by a connecting rod, and the sealing plug 250 seals the through hole 232; the inner cavity of the liquid suction nozzle 210 includes a Venturi section, and the Venturi section includes a contraction section 211, a throat 212 and a diffusion section 213, and the branch The cavity 220 includes a first branch cavity 221, a second branch cavity 222 and a third branch cavity 223, one end of the first branch cavity 221 is connected to the throat 212, the other end of the first branch cavity 221 is connected to the second branch cavity 222 and one end of the third branch cavity 223, the other end of the third branch cavity 223 is connected to the membrane cavity groove 231, the other end of the second branch cavity 222 extends to connect to the inner cavity of the liquid suction nozzle 210 and is connected to the upper end of the inner tube 260, the inner tube 260 extends downward along the length direction of the liquid suction nozzle 210, when the gun head body 110 is fixed, the lower end of the inner tube 260 extends from the lower end of the short tube 160 and is flush with the lower end of the cover wall 172.

[0031] Combination Figure 4 and 5 When in use, when the body inhales air, the gas flows in the inner cavity of the liquid suction nozzle 210, and the Venturi section is connected to the inner tube 260 by the connected second branch cavity 222 and also inhales air from the gun head body 110 to perform normal liquid inlet; when the liquid enters the buffer cavity 130, the buoyancy causes the film 174 to arch upward, and the lower end opening of the inner tube 260 is blocked by the negative pressure air suction film 174, and the inner tube 260 no longer inhales air, and the Venturi section can only absorb the gas in the membrane cavity groove 231 through the third branch cavity, so that a negative pressure is formed in the membrane cavity groove 231. Under the action of the negative pressure, the flexible membrane 240 drives the sealing plug 250 to move downward and disengage from the through hole 232. Since the through hole 232 is directly connected to the air, it is easier to inhale air, and the suction cavity 201 is inhaled from the through hole 232, and the liquid is no longer sucked in through the liquid suction nozzle 210, so as to avoid the reagent solution being sucked into the body 200 through the liquid suction nozzle, which is difficult to clean and cannot be completely cleaned, causing cross contamination. Ensure the body is clean, avoid reagent contamination and corrosion, and extend service life.

[0032] A partition 233 is provided in the through hole 232, and a second vent hole 234 is provided on the partition 233 to ensure air circulation. A first through hole 235 is provided in the middle of the partition 233. The upper end surface of the sealing plug 250 is fixed to the lower end of a short rod 251, and the short rod 251 passes through the first through hole 235. The outer side surface of the short rod 251 is slidably matched with the hole wall of the first through hole 235. A first spring 252 is sleeved on the outer side of the short rod 251. The upper end of the short rod 251 is fixed to a first pressing plate 253, and the diameter of the first pressing plate 253 is smaller than the diameter of the through hole 232. The upper and lower ends of the first spring 252 connect the first pressing plate 253 and the partition 233. When the first spring 252 is in a normal state, the upper surface of the sealing plug 250 is in contact with the lower surface of the partition 233, and the second vent hole 234 and the first through hole 235 are sealed. The length of the first pressing plate 253 from the upper surface of the partition 233 is greater than the thickness of the sealing plug 250. When in use, when overflow occurs, the sealing plug 250 moves downward to disengage from the through hole 232, and the first spring 252 is in a stretched state. When the air suction is completed, the membrane cavity groove 231 is no longer in a negative pressure state, and the first spring 252 returns to its original shape, pulling the sealing plug 250 to move into the through hole, sealing the through hole 232, and realizing automatic return to position, which is convenient for continued use.

[0033] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, changes and modifications made without departing from the spirit and scope of the present invention are all within the scope of patent protection of the present invention.

Claims

1. A contamination-resistant pipette, characterized in that: Including the gun head and the body; The lower part of the body is provided with a liquid suction nozzle, and also includes a locking part, and the locking part includes an outer tube, a locking tube and a locking piece, the upper end of the outer tube is fixed on the body, the outer tube is sleeved on the outside of the liquid suction nozzle, the length of the outer tube is greater than the length of the liquid suction nozzle, the locking tube is concentrically fixed to the lower end of the outer tube, the locking tube is provided with a locking hole, and the locking hole is truncated; the locking piece includes a locking bundle and a fixing seat, the locking bundle is fixed to one end of the fixing seat, a plurality of the locking bundles are equidistantly arranged along the circumference, the fixing seat is provided with a through hole matched with the lower end of the liquid suction nozzle, the locking piece is arranged in the outer tube, and the locking bundle is located in the locking hole; The diameter of the fixing seat is smaller than the inner diameter of the outer cylinder and larger than the diameter of the upper end of the locking hole; The gun tip comprises a gun tip body and a thin tube. The front end of the gun tip body is concentrically fixed with one end of the thin tube, and the thin tube is extended along the length direction of the gun tip body.

2. The anti-contamination pipette according to claim 1, characterized in that: The end of the locking beam away from the fixing seat is connected to a fixing ball, and a locking groove is provided on the gun head body. The locking groove is an annular groove, and the locking groove is arranged close to the tail end of the gun head body. The distance between the locking groove and the tail end of the gun head body is equal to the distance between the fixing ball and the lower end surface of the fixing seat.

3. The anti-contamination pipette according to claim 1, characterized in that: The shape of the through hole is the same as the shape of the lower end of the liquid suction nozzle. An annular groove is arranged in the through hole, and a sealing ring is embedded in the annular groove.

4. The anti-contamination pipette according to claim 1, characterized in that: An annular sealing gasket is provided on the side of the fixing seat facing the locking bundle, and the sealing gasket is arranged on the fixing seat on the inner side of the locking bundle. The sealing gasket is arranged concentrically with the locking bundle, and the outer diameter of the sealing gasket is smaller than the inner diameter of the locking bundle, and the inner diameter of the sealing gasket is larger than the diameter of the through hole of the end face of the fixing seat facing the locking bundle.

5. The anti-contamination pipette according to claim 1, characterized in that: The gun head body includes a cavity main section and a buffer section, wherein the buffer section is located at the rear end of the gun head body, the buffer section has a buffer cavity, and the cavity main section has a accommodating cavity. The buffer cavity and the accommodating cavity are connected through a connecting cavity, the diameter of the connecting cavity is smaller than the diameter of the accommodating cavity, and the diameter of the buffer cavity exceeds the diameter of the accommodating cavity.

6. The anti-contamination pipette according to claim 5, characterized in that: A circular hole is provided on the end face of the tail end of the gun head body, and the upper end of the short tube is concentrically connected to the circular hole. The lower end of the short tube extends into the buffer cavity. A fixed cover is also fixed to the outside of the short tube, and the fixed cover includes a cover plate and a cover wall. The short tube passes through the cover plate and is connected and fixed to the cover plate. A first air vent is also arranged on the cover plate. The upper end face of the cover wall is connected to the cover plate, and a film is fixed to the lower end face of the cover wall. The film is hemispherically arched, and the lower end of the short tube is blocked when the film is arched upward.

7. The anti-contamination pipette according to claim 6, characterized in that: The film is a rubber film, and an annular ridge is also provided on the end surface of the tail end of the gun head body. The annular ridge is located outside the circular hole, and the annular ridge is concentrically arranged with the circular hole.

8. The anti-contamination pipette according to claim 6, characterized in that: The body is also provided with a branch cavity, an open groove is provided on the side of the body, a membrane cavity groove is provided on one side groove wall of the open groove, a flexible membrane is fixed on the open end of the membrane cavity groove, a through hole is provided on the groove wall on the other side of the open groove to connect to the bottom of the suction cavity of the body, a sealing plug is fixed on the flexible membrane, and the sealing plug seals the through hole; the inner cavity of the liquid suction nozzle includes a Venturi section, and the Venturi section includes a contraction section, a throat and a diffusion section, and the branch cavity includes a first branch cavity, a second branch cavity and a third branch cavity, one end of the first branch cavity is connected to the throat, the other end of the first branch cavity is connected to one end of the second branch cavity and the third branch cavity, the other end of the third branch cavity is connected to the membrane cavity groove, the other end of the second branch cavity extends to connect to the inner cavity of the liquid suction nozzle and connects to the upper end of the inner tube, the inner tube extends downward along the length direction of the liquid suction nozzle, and when the gun head body is fixed, the lower end of the inner tube extends out from the lower end of the short tube and is flush with the lower end of the cover wall.

9. The anti-contamination pipette according to claim 8, characterized in that: A partition is provided in the through hole, a second air vent is provided on the partition, a first through hole is provided in the middle of the partition, the upper end face of the sealing plug is fixed to the lower end of the short rod, the short rod passes through the first through hole, the outer side surface of the short rod is slidably matched with the hole wall of the first through hole, a first spring is sleeved on the outer side of the short rod, a first pressure plate is fixed on the upper end of the short rod, the diameter of the first pressure plate is smaller than the diameter of the through hole, and the upper and lower ends of the first spring connect the first pressure plate and the partition.

10. The anti-contamination pipette according to claim 1, characterized in that: The body is also provided with a detachable push arm, which includes a push arm, a ring and a telescopic spring. The body is provided with an installation cavity, which includes a spring cavity. The push arm is arranged in the installation cavity, the lower end of the push arm is connected to the ring, and the ring is sleeved on the outside of the suction nozzle, the upper end of the push arm passes through the outside of the body and is connected to a fixed pressing plate; the telescopic spring is arranged in the spring cavity, the telescopic spring is sleeved outside the push arm, the lower end of the telescopic spring is connected to the lower end of the spring cavity, the upper end of the telescopic spring is connected to the second pressing plate, and the second pressing plate is fixed to the push arm.

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