Injection needle with sealing performance

Abstract

The invention discloses an injection needle with sealing performance. The injection needle comprises a negative pressure seat, an inner container needle seat and a plurality of needle tubes. A plurality of limiting guide cylinders are arranged on the end face of the lower end of a negative pressure seat, a plurality of needle seat cylinders are arranged on the end face of the lower end of an inner container needle seat, the needle seat cylinders are connected with the limiting guide cylinders in a one-to-one correspondence mode, and each limiting guide cylinder comprises an upper end sealing cavity, a middle sealing cavity and a lower end sealing cavity; the needle seat cylinder comprises an upper end cylinder, a middle cylinder and a lower end cylinder, the limiting guide cylinder and the needle seat cylinder are in stepped step-by-step sealing connection, the sealing effect of the injection needle can be improved, and the transparent cosmetic liquid is prevented from flowing back to the upper end of an inner cavity of the negative pressure seat in a multi-stage sealing connection mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a sealed injection needle. BACKGROUND

[0002] With the continuous development of the medical beauty industry, multi-head injection needles have become popular products in the medical beauty industry due to their high safety, small trauma, good cosmetic effect, and other characteristics. After the multi-head injection needle is assembled with the syringe, it is used with an electronic injection instrument. The transparent cosmetic liquid is injected into the subcutaneous dermis layer through the negative pressure principle, so as to improve the skin state of the patient's face and ultimately achieve the effect of beauty.

[0003] At present, most of the multi-head injection needles on the market include a needle seat, a needle tube, a cone seat, a negative pressure seat, and an adjusting seat. The adjusting seat and the negative pressure seat are tightly buckled, the liquid inlet luer connector of the cone seat has external threads, the center hole of the adjusting seat has internal threads, the center hole of the cone seat and the adjusting seat are threadedly connected, the rotating adjusting seat drives the cone seat, the needle seat, and the needle tube to move up and down, and the needle length of the needle tube changes, thereby achieving the purpose of adjusting the needle length. Such a structure is disclosed in patent CN220046829U. Because the inner cavity of the needle seat and the negative pressure seat is in a conical surface fitting mode, when the needle length of the needle tube is the longest, the inner wall surface of the needle seat and the negative pressure seat is in a tightly fitted state. When the needle length of the needle tube is shortened, a gap is generated between the inner wall surface of the needle seat and the negative pressure seat. Therefore, there is a risk that the transparent cosmetic liquid will flow back through the gap between the inner wall surface of the needle seat and the negative pressure seat to the upper end of the inner cavity of the negative pressure seat, and then overflow from the hollow hole (injection molding process hole) on the adjusting seat to the outside of the injection needle. SUMMARY

[0004] The injection needle provided by the embodiments of the present application can solve the technical problem that a gap is generated between the inner wall surface of the needle seat and the negative pressure seat, which causes the transparent cosmetic liquid to flow back through the gap between the inner wall surface of the needle seat and the negative pressure seat to the upper end of the inner cavity of the negative pressure seat, and then overflow from the hollow hole on the adjusting seat to the outside of the injection needle.

[0005] The embodiment of the present application provides a kind of injection needle with sealing performance, the injection needle includes negative pressure seat, inner container needle seat and several needle tubes;The inner container needle seat is installed in the inner cavity of the negative pressure seat, the lower end face of the negative pressure seat is equipped with several limiting guide cylinders, the lower end face of the inner container needle seat is equipped with several needle seat cylinders, the needle seat cylinder is connected with the limiting guide cylinder one by one, the needle tube is arranged in the needle seat cylinder, the needle tube protrudes from the lower end face of the negative pressure seat through the limiting guide cylinder;The limiting guide cylinder includes upper end sealing cavity, middle part sealing cavity and lower end sealing cavity, the inner diameter of the upper end sealing cavity is greater than the inner diameter of the middle part sealing cavity, the inner diameter of the middle part sealing cavity is greater than the inner diameter of the lower end sealing cavity, the inner diameter of the lower end sealing cavity is equal to the outer diameter of the needle tube, and the lower end sealing cavity is sealingly connected with the needle tube;The needle seat cylinder includes upper end cylinder, middle part cylinder and lower end cylinder, the outer diameter of the upper end cylinder is greater than the outer diameter of the middle part cylinder, the outer diameter of the middle part cylinder is greater than the outer diameter of the lower end cylinder, and the upper end cylinder is located at the upper edge opening position of the upper end sealing cavity, the middle part cylinder is sealingly arranged in the upper end sealing cavity, and the lower end cylinder is sealingly arranged in the middle part sealing cavity.

[0006] Further, the upper end sealing cavity, the middle part sealing cavity and the lower end sealing cavity are smoothly connected, the upper end cylinder, the middle part cylinder and the lower end cylinder are smoothly connected, the transition cavity surface between the upper end sealing cavity and the middle part sealing cavity is matched with the transition curved surface between the middle part cylinder and the lower end cylinder;When the needle seat cylinder extends into the bottom of the limiting guide cylinder, the transition curved surface is sealingly matched with the transition cavity surface.

[0007] Further, the outer side surface of the needle seat cylinder is clearance fitted with the inner side surface of the limiting guide cylinder, and the clearance of the clearance fit is in the range of 0-0.02mm.

[0008] Further, the outer side surface of the needle seat cylinder is interference fitted with the inner side surface of the limiting guide cylinder, and the interference amount of the interference fit is in the range of 0-0.15mm.

[0009] Further, the upper edge opening of the upper end sealing cavity is a flexible elastic thin-walled structure, the inner side of the upper edge opening of the upper end sealing cavity is provided with a ring buckle structure, the ring buckle structure is interference fitted with the middle part cylinder, and the interference amount of the interference fit is in the range of 0-0.15mm.

[0010] Further, the ring buckle structure is a right-angle type ring buckle, the right-angle side of the right-angle type ring buckle is flush with the upper edge opening of the upper end sealing cavity, and the inner diameter of the right-angle type ring buckle gradually increases from the upper edge opening of the upper end sealing cavity to the side towards the middle part sealing cavity;Or, The ring buckle structure is a rhombus type ring buckle, the upper end of the rhombus type ring buckle is flush with the upper edge opening of the upper end sealing cavity, the middle part of the rhombus type ring buckle is provided with a turning point, the inner diameter of the rhombus type ring buckle gradually decreases from the upper edge opening of the upper end sealing cavity to the turning point, and the inner diameter of the rhombus type ring buckle gradually increases from the turning point to the side of the middle part sealing cavity; or, The ring buckle structure is an arc type ring buckle, the upper end of the arc type ring buckle is flush with the upper edge opening of the upper end sealing cavity, and the inner diameter of the arc type ring buckle gradually decreases and then increases in an arc shape from the upper edge opening of the upper end sealing cavity to the side of the middle part sealing cavity.

[0011] Further, the outer side of the middle part cylinder is provided with a sealing protruding structure, and the sealing protruding structure is located at the position of the middle part cylinder adjacent to the lower end cylinder.

[0012] Further, the sealing protruding structure is a right angle type protrusion, the right angle side of the right angle type protrusion is flush with the lower edge of the middle part cylinder, and the outer diameter of the right angle type protrusion gradually decreases from the lower edge of the middle part cylinder to the side of the upper end cylinder; or, The sealing protruding structure is a rhombus type protrusion, the lower end of the rhombus type protrusion is flush with the lower edge of the middle part cylinder, the middle part of the rhombus type protrusion is provided with a protruding point, the outer diameter of the rhombus type protrusion gradually increases from the lower edge of the middle part cylinder to the protruding point, and the outer diameter of the rhombus type protrusion gradually decreases from the protruding point to the side of the upper end cylinder; or, The sealing protruding structure is an arc type protrusion, the upper end of the arc type protrusion is flush with the lower edge of the middle part cylinder, and the outer diameter of the arc type protrusion gradually increases and then decreases in an arc shape from the lower edge of the middle part cylinder to the side of the upper end cylinder.

[0013] Further, the injection needle further comprises a cone seat and an adjusting seat, the inside of the cone seat is provided with a hollow liquid guide pipe, the bottom surface of the cone seat is provided with a liquid distribution cavity, the liquid distribution cavity is connected with the needle seat cylinder one by one, and the top of the needle tube is communicated to the liquid distribution cavity; the center of the adjusting seat is provided with a threaded through hole, the outer side of the cone seat is provided with an outer threaded circular table, the outer threaded circular table is threadedly connected with the threaded through hole, a plurality of clamping blocks are arranged on the peripheral wall surface of the adjusting seat in a ring direction, and the outer part of the negative pressure seat is provided with a ring eave body; the adjusting seat is clamped on the ring eave body through the clamping blocks.

[0014] Further, the top of the inner container needle seat is further provided with a plurality of positioning bosses, the positioning bosses are arranged at intervals with the needle seat cylinder, the bottom surface of the cone seat is provided with a plurality of limiting grooves, and the positioning bosses are connected with the limiting grooves one by one.

[0015] The injection needle with sealing performance provided by the embodiment of the application comprises a negative pressure seat, an inner container needle seat and a plurality of needle tubes, the lower end surface of the negative pressure seat is provided with a plurality of limiting guide cylinders, the lower end surface of the inner container needle seat is provided with a plurality of needle seat cylinders, the needle seat cylinders are connected with the limiting guide cylinders one by one, the limiting guide cylinders comprise an upper end sealing cavity, a middle part sealing cavity and a lower end sealing cavity, the needle seat cylinders comprise an upper end cylinder, a middle part cylinder and a lower end cylinder, the limiting guide cylinders and the needle seat cylinders are connected in a stepped manner, the sealing effect of the injection needle can be improved, and the multi-stage sealing connection mode can avoid the transparent beauty liquid from flowing back to the upper end of the inner cavity of the negative pressure seat. BRIEF DESCRIPTION OF DRAWINGS

[0016] The technical scheme and other beneficial effects of the application will be apparent through the following detailed description of the specific embodiments of the application in combination with the drawings.

[0017] Figure 1 The structural schematic diagram of the injection needle with sealing performance provided by the embodiment of the application is shown in the figure. Figure 2 The exploded structural schematic diagram of the injection needle with sealing performance provided by the embodiment of the application is shown in the figure. Figure 3 The sectional view of the injection needle with sealing performance provided by the embodiment of the application is shown in the figure. Figure 4 The assembly structural schematic diagram of the injection needle with sealing performance provided by the embodiment of the application is shown in the figure. Figure 5 The structural schematic diagram of the inner container needle seat arranged in the negative pressure seat provided by the embodiment of the application is shown in the figure. Figure 6 The structural schematic diagram of the negative pressure seat provided by the embodiment of the application is shown in the figure. Figure 7 The structural schematic diagram of the inner container needle seat provided by the embodiment of the application is shown in the figure. Figure 8 The sectional view of the inner container needle seat provided by the embodiment of the application is shown in the figure. Figure 9 The connection structural schematic diagram of the needle seat cylinder and the limiting guide cylinder provided by the embodiment of the application is shown in the figure. Figure 10 The structural schematic diagram of the limiting guide cylinder provided by the embodiment of the application is shown in the figure. Figure 11 The first local enlarged view of the structure in which the limiting guide cylinder is provided with a ring buckle structure provided by the embodiment of the application is shown in the figure. Figure 12 The second local enlarged view of the structure in which the limiting guide cylinder is provided with a ring buckle structure provided by the embodiment of the application is shown in the figure. Figure 13 The third local enlarged view of the structure in which the limiting guide cylinder is provided with a ring buckle structure provided by the embodiment of the application is shown in the figure. Figure 14 The structure schematic diagram of the needle seat cylinder provided by the embodiment of the present application is shown in the figure; Figure 15 The first structure partial enlarged view of the needle seat cylinder provided by the embodiment of the present application is shown in the figure; Figure 16 The second structure partial enlarged view of the needle seat cylinder provided by the embodiment of the present application is shown in the figure; Figure 17 The third structure partial enlarged view of the needle seat cylinder provided by the embodiment of the present application is shown in the figure; Figure 18 The structure schematic diagram of the taper seat provided by the embodiment of the present application is shown in the figure; Figure 19 The structure schematic diagram of the adjusting seat provided by the embodiment of the present application is shown in the figure; Figure 20 The cooperation structure schematic diagram of the taper seat, the negative pressure seat, the inner container needle seat and the several needle tubes provided by the embodiment of the present application is shown in the figure.

[0018] The identification in the figure is as follows: The negative pressure seat 1, the limiting guide cylinder 11, the upper end sealing cavity 111, the middle part sealing cavity 112, the lower end sealing cavity 113, the ring buckle structure 12, the ring eaves body 13, the inner container needle seat 2, the needle seat cylinder 21, the upper end cylinder 211, the middle part cylinder 212, the lower end cylinder 213, the sealing protruding structure 22, the positioning boss 23, the guide positioning rib 24, the needle tube 3, the taper seat 4, the empty guide liquid tube 41, the liquid separation cavity 42, the outer thread circular table 43, the limiting groove, the guide groove 44, the adjusting seat 5, the threaded through hole 51, the clamping block 52. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms “mounting”, “connection”, “connecting” should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, or the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0021] Specifically, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 The embodiment of the present application provides a kind of injection needle with sealing performance, the injection needle includes negative pressure seat 1, inner container needle seat 2 and several needle tubes 3;The inner container needle seat 2 is installed in the inner cavity of the negative pressure seat 1, the lower end face of the negative pressure seat 1 is equipped with several limit guide cylinders 11, the lower end face of the inner container needle seat 2 is equipped with several needle seat cylinders 21, the needle seat cylinder 21 is connected with the limit guide cylinder 11 one by one, the needle tube 3 is arranged in the needle seat cylinder 21, the needle tube 3 protrudes from the lower end face of the negative pressure seat 1 by passing through the limit guide cylinder 11.

[0022] Please refer to Figure 9 , Figure 10 , Figure 14 The limit guide cylinder 11 includes upper end sealing cavity 111, middle part sealing cavity 112 and lower end sealing cavity 113, the inner diameter of the upper end sealing cavity 111 is greater than the inner diameter of the middle part sealing cavity 112, the inner diameter of the middle part sealing cavity 112 is greater than the inner diameter of the lower end sealing cavity 113, the inner diameter of the lower end sealing cavity 113 is equal to the outer diameter of the needle tube 3, and the lower end sealing cavity 113 is sealingly connected with the needle tube 3;The needle seat cylinder 21 includes upper end cylinder 211, middle part cylinder 212 and lower end cylinder 213, the outer diameter of the upper end cylinder 211 is greater than the outer diameter of the middle part cylinder 212, the outer diameter of the middle part cylinder 212 is greater than the outer diameter of the lower end cylinder 213, the upper end cylinder 211 is located at the upper edge opening position of the upper end sealing cavity 111, the middle part cylinder 212 is sealingly arranged in the upper end sealing cavity 111, and the lower end cylinder 213 is sealingly arranged in the middle part sealing cavity 112.

[0023] The limit guide cylinder 11 and the needle seat cylinder 21 are connected in a stepped manner in the embodiment of the present application, which can improve the sealing effect of the injection needle, and the multi-stage sealing connection mode can avoid the transparent beauty liquid from flowing back to the inner cavity of the negative pressure seat 1.

[0024] Among them, the upper end sealing cavity 111, the middle part sealing cavity 112 and the lower end sealing cavity 113 constitute a needle hole. The needle tube 3 is arranged at a specified height of the needle hole and is fixed by environment-friendly quick-drying glue.

[0025] Please refer to Figure 9, the upper end sealing cavity 111, the middle sealing cavity 112 and the lower end sealing cavity 113 are connected smoothly, the upper end cylinder 211, the middle cylinder 212 and the lower end cylinder 213 are connected smoothly, the transition cavity surface between the upper end sealing cavity 111 and the middle sealing cavity 112 is matched with the transition curved surface between the middle cylinder 212 and the lower end cylinder 213; when the needle seat cylinder 21 extends into the bottom of the limiting guide cylinder 11, the transition curved surface and the transition cavity surface are sealed.

[0026] Further, the outer side of the needle seat cylinder 21 is clearance fit with the inner side of the limiting guide cylinder 11, the clearance of the clearance fit is in the range of 0-0.02mm.

[0027] Further, the outer side of the needle seat cylinder 21 is interference fit with the inner side of the limiting guide cylinder 11, the interference of the interference fit is in the range of 0-0.15mm.

[0028] Further, the upper edge opening of the upper end sealing cavity 111 is a flexible and elastic thin-walled structure, the inner side of the upper edge opening of the upper end sealing cavity 111 is provided with a ring buckle structure 12, the ring buckle structure 12 is interference fit with the middle cylinder 212, the interference of the interference fit is in the range of 0-0.15mm.

[0029] Please refer to Figure 11 , the ring buckle structure 12 is a right-angle type ring buckle, the right-angle side of the right-angle type ring buckle is flush with the upper edge opening of the upper end sealing cavity 111, the inner diameter of the right-angle type ring buckle gradually increases from the upper edge opening of the upper end sealing cavity 111 to the side towards the middle sealing cavity 112; or, Please refer to Figure 12 , the ring buckle structure 12 is a diamond type ring buckle, the upper end of the diamond type ring buckle is flush with the upper edge opening of the upper end sealing cavity 111, the middle part of the diamond type ring buckle is provided with a turning point, the inner diameter of the diamond type ring buckle gradually decreases from the upper edge opening of the upper end sealing cavity 111 to the turning point, the inner diameter of the diamond type ring buckle gradually increases from the turning point to the side towards the middle sealing cavity 112; or, Please refer to Figure 13 , the ring buckle structure 12 is an arc type ring buckle, the upper end of the arc type ring buckle is flush with the upper edge opening of the upper end sealing cavity 111, the inner diameter of the arc type ring buckle is arc-shaped and gradually decreases and then increases from the upper edge opening of the upper end sealing cavity 111 to the side towards the middle sealing cavity 112.

[0030] Further, the outer side of the middle cylinder 212 is provided with a sealing protruding structure 22, the sealing protruding structure 22 is located at the position of the middle cylinder 212 adjacent to the lower end cylinder 213.

[0031] Please refer to Figure 15 , the sealing convex structure 22 is a right angle type convex, the right angle type convex is flush with the lower edge of the middle cylinder 212, the outer diameter of the right angle type convex gradually reduces from the lower edge of the middle cylinder 212 to the side of the upper end cylinder 211; or, Please refer to Figure 16 , the sealing convex structure 22 is a diamond type convex, the lower end of the diamond type convex is flush with the lower edge of the middle cylinder 212, the middle part of the diamond type convex is provided with a convex point, the outer diameter of the diamond type convex gradually increases from the lower edge of the middle cylinder 212 to the convex point, and the outer diameter of the diamond type convex gradually reduces from the convex point to the side of the upper end cylinder 211; or, Please refer to Figure 17 , the sealing convex structure 22 is an arc type convex, the upper end of the arc type convex is flush with the lower edge of the middle cylinder 212, and the outer diameter of the arc type convex is arc-shaped and first increases and then decreases from the lower edge of the middle cylinder 212 to the side of the upper end cylinder 211.

[0032] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 18 , Figure 19 , Figure 20 , the injection needle further comprises a cone seat 4 and an adjusting seat 5, the inside of the cone seat 4 is provided with a hollow liquid guide pipe 41, the bottom surface of the cone seat 4 is provided with a distribution cavity 42, the distribution cavity 42 is connected with the needle seat cylinder 21 one by one, and the top of the needle tube 3 is communicated to the distribution cavity 42; the center of the adjusting seat 5 is provided with a threaded through hole 51, the outer side of the cone seat 4 is provided with an outer threaded circular table 43, the outer threaded circular table 43 is threadedly connected with the threaded through hole 51, a plurality of clamping blocks 52 are arranged on the peripheral wall surface of the adjusting seat 5 in a ring direction, the outside of the negative pressure seat 1 is provided with a ring eave body 13, and the adjusting seat 5 is clamped on the ring eave body 13 through the clamping block 52.

[0033] Preferably, the threaded through hole 51 is provided with an inner double thread, the outer threaded circular table 43 is provided with an outer double thread, and the outer double thread is matched with the inner double thread when the cone seat 4 is matched with the adjusting seat 5.

[0034] Please refer to Figure 5 , Figure 6 , Figure 7 , Figure 8The top of the inner liner needle seat 2 is also provided with a plurality of positioning bosses 23, which are arranged at intervals with the needle seat cylinder 21, and the bottom surface of the cone seat 4 is provided with a plurality of limiting grooves, and the positioning bosses 23 and the limiting grooves are connected one by one.

[0035] Please refer to Figure 20 The bottom surface edge of the cone seat 4 is provided with a guide groove 44, and the inner groove edge of the inner liner needle seat 2 is provided with a guide positioning rib 24, which is fixed in the guide groove 44 to realize the connection of the cone seat 4 and the inner liner needle seat 2. When the cone seat 4 and the inner liner needle seat 2 are matched, the guide groove 44 falls to the designated position through the guide positioning rib 24.

[0036] The injection needle provided by the embodiment has sealing performance. The injection needle includes a negative pressure seat 1, an inner liner needle seat 2 and a plurality of needle tubes 3. The lower end surface of the negative pressure seat 1 is provided with a plurality of limiting guide cylinders 11. The lower end surface of the inner liner needle seat 2 is provided with a plurality of needle seat cylinders 21. The needle seat cylinders 21 and the limiting guide cylinders 11 are connected one by one. The limiting guide cylinders 11 include an upper end sealing cavity 111, a middle part sealing cavity 112 and a lower end sealing cavity 113. The needle seat cylinders 21 include an upper end cylinder 211, a middle part cylinder 212 and a lower end cylinder 213. The limiting guide cylinders 11 and the needle seat cylinders 21 are connected in a stepped and sealed manner, which can improve the sealing effect of the injection needle. The multi-stage sealing connection mode can prevent the transparent beauty liquid from flowing back to the upper end of the inner cavity of the negative pressure seat 1.

[0037] In the above embodiments, the description of each embodiment has its own emphasis. The parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0038] The above describes in detail the injection needle with sealing performance provided by the embodiment. The principle and implementation of the application are described by applying specific examples. The above description of the embodiments is only used to help understand the technical solutions and core ideas of the application. Those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments.

Claims

1. An injection needle with sealing performance, characterized in that: The injection needle includes a negative pressure seat, an inner liner needle seat and a plurality of needle tubes; the inner liner needle seat is installed in the inner cavity of the negative pressure seat, the lower end surface of the negative pressure seat is provided with a plurality of limiting guide cylinders, the lower end surface of the inner liner needle seat is provided with a plurality of needle seat cylinders, the needle seat cylinders are connected to the limiting guide cylinders in a one-to-one correspondence, the needle tube is arranged in the needle seat cylinder, the needle tube passes through the limiting guide cylinder and protrudes from the lower end surface of the negative pressure seat; the limiting guide cylinder includes an upper sealing cavity, a middle sealing cavity and a lower sealing cavity, the inner diameter of the upper sealing cavity is larger than that of the middle sealing cavity Inner diameter, the inner diameter of the middle sealed cavity is greater than the inner diameter of the lower sealed cavity, the inner diameter of the lower sealed cavity is equal to the outer diameter of the needle tube, and the lower sealed cavity is sealed and connected to the needle tube; the needle seat cylinder includes an upper cylinder, a middle cylinder and a lower cylinder, the outer diameter of the upper cylinder is greater than the outer diameter of the middle cylinder, the outer diameter of the middle cylinder is greater than the outer diameter of the lower cylinder, the upper cylinder is located at the upper edge of the upper sealed cavity, the middle cylinder is sealed in the upper sealed cavity, and the lower cylinder is sealed in the middle sealed cavity.

2. The sealing injection needle according to claim 1, wherein: The upper sealed cavity, the middle sealed cavity and the lower sealed cavity are smoothly transitionally connected, the upper cylinder, the middle cylinder and the lower cylinder are smoothly transitionally connected, and the transition cavity surface between the upper sealed cavity and the middle sealed cavity is adapted to the shape of the transition curved surface between the middle cylinder and the lower cylinder; when the needle seat cylinder extends into the bottom of the limiting guide cylinder, the transition curved surface is sealed and matched with the transition cavity surface.

3. The injection needle with sealing performance according to claim 1, characterized in that: The outer side surface of the needle seat cylinder and the inner side surface of the limiting guide cylinder are clearance-matched, and the clearance of the clearance fit is in the range of 0-0.02mm.

4. The injection needle with sealing performance according to claim 1, characterized in that: The outer side surface of the needle seat cylinder and the inner side surface of the limiting guide cylinder are interference fit, and the interference amount of the interference fit is in the range of 0-0.15mm.

5. The injection needle with sealing performance according to claim 1, characterized in that: The upper edge of the upper sealing cavity is a flexible elastic thin-wall structure, and a buckle structure is provided on the inner side of the upper edge of the upper sealing cavity. The buckle structure is interference fit with the middle cylinder, and the interference fit is in the range of 0-0.15mm.

6. The injection needle with sealing performance according to claim 5, characterized in that: The buckle structure is a right-angle buckle, the right-angle side of the right-angle buckle is flush with the upper edge of the upper sealed cavity, and the inner diameter of the right-angle buckle gradually increases from the upper edge of the upper sealed cavity to the inner diameter of the side toward the middle sealed cavity; or, The ring buckle structure is a diamond-shaped ring buckle, the upper end of the diamond-shaped ring buckle is flush with the upper edge of the upper sealed cavity, a turning point is provided in the middle of the diamond-shaped ring buckle, the inner diameter of the diamond-shaped ring buckle gradually decreases from the upper edge of the upper sealed cavity to the turning point, and the inner diameter of the diamond-shaped ring buckle gradually increases from the turning point to the side facing the middle sealed cavity; or, The buckle structure is an arc-shaped buckle, the upper end of the arc-shaped buckle is flush with the upper edge of the upper sealing cavity, and the inner diameter of the arc-shaped buckle decreases and then increases in an arc shape from the upper edge of the upper sealing cavity to the inner diameter toward the side of the middle sealing cavity.

7. The injection needle with sealing performance according to claim 1, characterized in that: A sealing protrusion structure is provided on the outer side of the middle cylinder, and the sealing protrusion structure is located at a position of the middle cylinder adjacent to the lower cylinder.

8. The injection needle with sealing performance according to claim 7, characterized in that: The sealing protrusion structure is a right-angled protrusion, the right-angled side of the right-angled protrusion is flush with the lower edge of the middle cylinder, and the outer diameter of the right-angled protrusion gradually decreases from the lower edge of the middle cylinder to the outer diameter toward the upper end cylinder; or, The sealing protrusion structure is a diamond-shaped protrusion, the lower end of the diamond-shaped protrusion is flush with the lower edge of the middle cylinder, a protrusion point is provided in the middle of the diamond-shaped protrusion, the outer diameter of the diamond-shaped protrusion gradually increases from the lower edge of the middle cylinder to the protrusion point, and the outer diameter of the diamond-shaped protrusion gradually decreases from the protrusion point to the side facing the upper cylinder; or, The sealing protrusion structure is an arc-shaped protrusion, the upper end of the arc-shaped protrusion is flush with the lower edge of the middle cylinder, and the outer diameter of the arc-shaped protrusion increases and then decreases in an arc shape from the lower edge of the middle cylinder to the outer diameter toward the upper end cylinder.

9. The injection needle with sealing performance according to claim 1, characterized in that: The injection needle also includes a cone seat and an adjustment seat. The cone seat is provided with a hollow liquid guide tube. The bottom surface of the cone seat is provided with a liquid separation cavity. The liquid separation cavity is connected to the needle seat cylinder in a one-to-one correspondence. The top of the needle tube is connected to the liquid separation cavity. The center of the adjustment seat is provided with a threaded through hole. The outer side of the cone seat is provided with an external threaded cone. The external threaded cone is threadedly connected to the threaded through hole. A number of clamping blocks are provided at intervals along the circumferential direction on the circumferential wall surface of the adjustment seat. The outside of the negative pressure seat is provided with an annular eaves body, and the adjustment seat is clamped on the annular eaves body through the clamping blocks.

10. The injection needle with sealing performance according to claim 9, characterized in that: The top of the inner needle seat is further provided with a plurality of positioning bosses, the positioning bosses and the needle seat cylinder are spaced apart, the bottom surface of the cone seat is provided with a plurality of limiting grooves, and the positioning bosses are connected to the limiting grooves in a one-to-one correspondence.

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