A pre-filled flush syringe with filter, anti-dislodgement cap and anti-reuse

Abstract

The application discloses a pre-filled flush syringe with filtering, anti-cap-off and anti-secondary use functions, and belongs to the medical instrument field. The pre-filled flush syringe comprises a core rod, a piston, a sleeve and a protective cap. The top of the sleeve is provided with a taper head with a snap ring, the outer side of the taper head is a fixing cylinder with a fixing cylinder thread and a fixing ring, and the protective cap is composed of an inner ring with a protective cap thread and a filter element, and an outer ring with a detachable locking ring. The protective cap is prevented from falling off during high-pressure sterilization through cooperation of the fixing cylinder thread and the protective cap thread, and cooperation of the fixing cylinder fixing ring and the protective cap locking ring. The anti-secondary use is realized by separating the locking ring from the protective cap outer ring and retaining the fixing ring when the protective cap is pulled out. The injection liquid is filtered through embedding the filter element into the taper head snap ring. The application can avoid the protective cap from falling off during sterilization, secondary misuse after use, filter injection liquid impurities, and improve the use safety and reliability.

Description

Technical Field

[0001] This invention belongs to the field of medical devices, specifically relating to a pre-filled flushing syringe with filtering, anti-cap removal, and anti-reuse features. Background Technology

[0002] In the medical field, pre-filled flushing syringes are widely used for flushing various catheters. However, existing pre-filled flushing syringes have several problems:

[0003] 1. Problem of Protective Cap Easily Falling Off: Currently, the protective caps and sleeve cones of syringes mostly use a simple snap-fit ​​or interference fit structure. During the autoclaving process, temperature changes, pressure shocks, and the thermal expansion and contraction of materials can cause the stability of the fit between the protective cap and the cone to decrease, making it prone to falling off. A detached protective cap not only leads to contamination of the rinsing solution but also exposes the cone to the external environment, increasing the risk of microbial contamination and seriously affecting product quality and safety.

[0004] 2. Lack of self-destruct detection: In clinical use, some syringes may not show obvious signs of use, leading to the possibility of mistakenly using a used syringe for secondary procedures. Current technology lacks an effective self-destruct or usage status identification structure, making it impossible to visually determine whether a syringe has been used. This poses a safety hazard to medical procedures and may lead to cross-infection and other medical accidents.

[0005] 3. Insufficient filtration effect of injection solution: Although some syringes have internal filtration structures, the existing filtration structures are mostly fixed inside the cone tip. During syringe assembly or use, they are prone to displacement and blockage, and reduce the efficiency of filling the syringe sleeve with liquid during the production process. In addition, some filtration structures are integrated with the protective cap. When the protective cap is removed, the filtration structure is removed along with the protective cap. It cannot continuously perform filtration during the delivery of injection solution, and it is difficult to effectively intercept microparticles (such as rubber fragments, drug sediment) or possible microorganisms in the injection solution, which increases the probability of adverse reactions in patients.

[0006] Therefore, developing a pre-filled flushing injector that can solve the above problems is of great practical significance.

[0007] In recent years, people have carried out many meaningful explorations in the development of pre-filled flushing injectors.

[0008] Patent 2013101146913 discloses a safety-type pre-filled syringe, which has at least one protective barrier on the channel connecting the outer surface of the cone to the outside, fully protecting the cone part that comes into direct contact with the connector during use and preventing infection caused by cone contamination. The locking cap adopts an inner and outer ring structure, with the outer ring extending downward to cover the top surface of the fixed cylinder, protecting the cap threads that may come into contact with liquid and reducing the risk of contamination. The addition of the outer ring structure to the locking cap results in a larger cap diameter, making it easier and less strenuous to tighten. The outer ring of the locking cap can also serve as a force point when tightening the cap, shortening the length of the cap part used for tightening in existing technologies and saving packaging materials. However, the patent fails to prevent the protective cap from falling off during autoclaving.

[0009] Patent 2024112479330 discloses a pre-filled syringe. This pre-filled syringe features a filter buffer added after the plunger to form a buffer chamber. During cryopreservation and thawing, the gas within the buffer chamber can slowly exchange with the outside through a filter pore with a diameter of only 0.22µm until pressure equilibrium is achieved. This process mitigates the impact of rapid temperature changes on the medication and plunger, preventing plunger displacement due to rapid pressure changes, a common problem in existing technologies, thus eliminating the risk of medication contamination due to seal failure. Furthermore, the filter pore, less than or equal to 0.22µm, not only buffers gas exchange during pressure changes but also filters air entering the buffer chamber, preventing particles and microorganisms from entering. The buffer chamber maintains a sterile and pure state, so even if the plunger shifts unexpectedly due to pressure changes, it will not contaminate the medication. However, the filter buffer, fixed inside the cone tip, is prone to displacement and blockage during syringe assembly or use, and reduces the efficiency of filling the syringe sleeve during production.

[0010] Patent 2020105344612 discloses a pre-filled flushing syringe designed to prevent reuse. The patented structure includes a sleeve, a piston, and a pull rod. The sleeve comprises at least a sleeve body, a baffle, an internally threaded tube, an externally threaded cap, and a connecting tube. The externally threaded cap has a sealing end cap at its front end that tightly contacts and seals the connecting tube. The piston is sealed to the inner wall of the sleeve, and the pull rod is located at the lower end of the piston. It can seal the internally threaded tube by using the externally threaded cap and the sealing end cap. During use, the externally threaded cap is unscrewed, and the connecting tube is then connected to the infusion device. Reuse is prevented by the failure of the piston or pull rod, thus achieving a self-destructive effect. However, the patent still has the problem of structural fragility, and it may self-destruct during production due to improper operation. Summary of the Invention

[0011] The purpose of this invention is to overcome the shortcomings of existing pre-filled flushing syringes, such as the lack of an injection fluid filtration structure, easy detachment of the protective cap during autoclaving, and lack of identification function to prevent reuse, and to provide a pre-filled flushing syringe with filtration, anti-cap detachment, and anti-reuse features.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] A pre-filled flushing syringe with filtering, anti-cap-removal, and anti-reuse functions includes a core rod, a piston, a sleeve, and a protective cap. The piston is slidably fitted inside the sleeve, and one end of the core rod is fixedly connected to the piston. The top of the sleeve has an integrally formed conical head for connecting a catheter connector, and a retaining ring is provided circumferentially on the inner wall of the conical head. A fixing sleeve is coaxially fixed to the outer side of the sleeve conical head, with a fixing sleeve thread on the inner side and a fixing ring and fixing threads integrally formed on the outer circumference. The protective cap consists of an inner protective cap ring and an outer protective cap ring; the outer wall of the inner protective cap ring has a protective cap thread, and a filter element is nested within the inner protective cap ring; a locking ring is provided at the bottom of the outer protective cap ring, connected to the outer protective cap ring via an easy-tear point, and the inner wall of the locking ring has locking threads that match the fixing threads.

[0014] Furthermore, the fixing cylinder and the sleeve are integrally injection molded structures, and the raw materials are one or more of PP, PE or COC. The piston material is one or more of polyisoprene rubber, butyl rubber, halogenated butyl rubber, silicone rubber or EPDM rubber; the core rod and protective cap are made of one or more of PP, PE or COC.

[0015] Furthermore, the retaining rings on the inner wall of the cone head have a raised or recessed structure, and the number of retaining rings can be 1-3.

[0016] Furthermore, the inner ring of the protective cap is fixed to the filter element via ultrasonic welding, or it can be directly fixed to the inner side of the inner ring of the protective cap without welding, thus ensuring that the filter element and the inner ring of the protective cap can be separated. The filter element has an annular groove or annular protrusion that matches the retaining ring on the inner wall of the cone. During the tightening of the protective cap, the threads of the protective cap and the fixed cylinder slide relative to each other, pushing the filter element into the cone, and finally the annular groove or annular protrusion of the filter element engages with the retaining ring on the inner wall of the cone. During the loosening and removal of the protective cap, the annular groove or annular protrusion of the filter element engages with the retaining ring on the inner wall of the cone and cannot move, thus the filter element detaches from the protective cap and is fixed inside the cone.

[0017] Furthermore, the filter element raw material is one or more of polyethersulfone, nylon, or mixed cellulose esters, and the filter element pore size is 0.22-5µm. After the protective cap is removed, during normal operation of the pre-filled syringe, the 5µm pore size filter element can filter out most of the potentially present insoluble particles. As the filter element pore size decreases, when the pore size is ≤0.45µm, it can achieve filtration and sterilization. If the pre-filled liquid in the sleeve is contaminated with bacteria and goes undetected, the microorganisms in the sleeve are blocked by the filter element, ensuring the safety of the injected liquid. The filter element raw material is one or more of polyethersulfone, nylon, or mixed cellulose esters, which can be confirmed according to the properties of the pre-filled liquid in the sleeve. If the pre-filled liquid is a non-polar liquid, the filter element material is made of an oil-based material; if the pre-filled liquid is a non-polar liquid, the filter element material is made of an aqueous material.

[0018] Furthermore, the pitch between the protective cap thread and the fixed sleeve thread is 0.5-1mm, and the thread mating length is 5-8mm.

[0019] Furthermore, the outer wall of the protective cap's outer ring is provided with anti-slip texture, which can be one of the following: diamond pattern, stripe pattern, or grid pattern, to prevent slipping when twisting the protective cap.

[0020] Furthermore, the fixing ring on the outer wall of the fixing cylinder can be designed as a raised or recessed shape.

[0021] Furthermore, when the retaining ring has a raised design, the retaining thread is located below the retaining ring. During the tightening of the protective cap, the external force pushes the locking ring of the protective cap to slightly deform and expand. After passing the retaining ring, the locking ring of the protective cap returns to its original shape. As the protective cap is tightened, during the contact between the locking ring and the retaining ring, the initial contact area is the upper end of the retaining ring and the lower end of the locking thread of the locking ring; after the locking ring passes the retaining ring, the contact area is the lower end of the retaining ring and the upper end of the locking thread of the locking ring. The upper end of the retaining ring to the lower end forms a gradually rising arc or triangular slope, and the lower end of the locking thread to the upper end forms a gradually rising arc or triangular slope, which facilitates the gradual expansion of the locking ring during the sliding of the retaining ring. The lower end of the retaining ring is a vertical plane perpendicular to the axis of the retaining cylinder, and the upper end of the locking thread is a vertical plane perpendicular to the axis of the outer ring of the protective cap. After the locking ring passes over the retaining ring, the two vertical planes meet, preventing the locking ring from slipping off the retaining ring again during the loosening and removal of the protective cap, ensuring that the locking ring remains below the retaining ring. The retaining thread is located below the retaining ring. After the locking ring passes over the retaining ring, the locking thread and the retaining thread can mesh with each other. During the tightening of the protective cap, the locking thread can slide relative to the retaining thread. During the unscrewing of the protective cap, the locking thread and the retaining thread lock together, preventing the locking ring from rotating with the protective cap and thus detaching the locking ring from the protective cap.

[0022] Furthermore, when the retaining ring is recessed, the retaining thread is located inside the retaining ring. After the locking ring and the retaining ring are engaged, the locking thread and the retaining thread can mesh with each other. During the tightening of the protective cap, the locking thread can slide relative to the retaining thread. During the unscrewing of the protective cap, the locking thread and the retaining thread lock together to prevent the locking ring from rotating with the protective cap, thereby causing the locking ring to detach from the protective cap and remain in the position of the retaining ring.

[0023] Furthermore, the number of easy-tear points is 2-10, evenly distributed along the circumferential direction of the mating surface between the outer ring of the protective cap and the locking ring. During the process of unscrewing the protective cap, the locking threads and the fixing threads lock together to prevent the locking ring from rotating with the protective cap. Under the action of external force, the easy-tear points break, and the locking ring and the protective cap separate.

[0024] Compared with the prior art, the pre-filled flushing syringe of the present invention, which features filtering, anti-cap removal, and anti-reuse, has the following beneficial effects:

[0025] (1) Anti-cap removal function: Through the cooperation of the protective cap thread and the fixed cylinder thread, and the cooperation of the locking ring and the fixed ring, the protective cap can be effectively fixed during the high-pressure sterilization process, avoiding the protective cap from falling off due to temperature changes, ensuring that the inside of the syringe is not contaminated, and ensuring the sterilization effect.

[0026] (2) Self-destruction identification function to prevent secondary use: When using, rotate and pull out the protective cap. The locking ring will separate from the outer ring of the protective cap and remain at the fixed ring. Medical staff can quickly determine whether the syringe has been used by observing whether there is a locking ring at the fixed ring, thereby avoiding secondary misuse and reducing the risk of cross-infection.

[0027] (3) Filtration function: The filter element is embedded with a cone-shaped retaining ring during the removal of the protective cap, which can filter the injection solution when the syringe is used, effectively removing microparticles and microorganisms in the drug solution, preventing impurities from entering the human body and causing adverse events, and improving the safety of use. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a cross-sectional view of the overall structure of a pre-filled flushing syringe;

[0030] Figure 2 This is a schematic diagram of the cone head and the fixed cylinder;

[0031] Figure 3A schematic diagram of the protective cap structure;

[0032] Figure 4 A cross-sectional view of the structure after the protective cap has been removed;

[0033] Reference numerals: 1-Core rod, 2-Piston, 3-Sleeve, 4-Protective cap, 5-Cone, 6-Annular ridge, 7-Push plate, 8-Sealing ring, 9-Snap ring, 10-Filter element, 11-Fixing cylinder, 12-Fixing cylinder thread, 13-Fixing ring, 14-Outer ring of protective cap, 15-Locking ring, 16-Fixing thread, 17-Inner ring of protective cap, 18-Thread of protective cap, 19-Easily broken point, 20-Locking thread, 21-Annular protrusion, 22-Groove of protective cap. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0035] It should be understood that the terms "upper", "lower", "left", "right", "front", "rear", "middle", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of the present invention.

[0036] This embodiment mainly describes the structure of a pre-filled flushing injector, combined with... Figures 1-4 The present invention provides a pre-filled flushing syringe with filtering, anti-cap removal, and anti-reuse functions, mainly comprising a core rod 1, a piston 2, a sleeve 3, and a protective cap 4. One end of the core rod 1 has an integrally formed push plate 7, which facilitates the movement of the core rod 1 by medical personnel. The other end of the core rod 1 has anti-slip textures to increase friction between the hand and the core rod 1, preventing slippage during operation. The piston 2 is installed inside the sleeve 3, and the outer wall of the piston 2 has a sealing ring 8 that matches the inner wall of the sleeve 3. The sealing ring 8 is made of medical-grade nitrile rubber, which has good sealing performance and elasticity, preventing leakage of the injection solution during the injection process.

[0037] The top of the sleeve 3 is integrally formed with a cone head 5 for connecting with the catheter connector. The outer wall of the cone head 5 is provided with 3 annular protrusions 6, which are evenly distributed along the axial direction of the cone head 5. This can enhance the sealing performance after the cone head 5 is connected to the catheter connector and prevent leakage of the medicine. The inner wall of the cone head 5 is integrally formed with a retaining ring 9, which is used to fix the filter element 10.

[0038] A fixing sleeve 11 is fixedly fitted on the outside of the sleeve 3 cone head 5 by injection molding. The fixing sleeve 11 has a fixing sleeve thread 12 on the inside. A fixing ring 13 is integrally formed on the outer circumference. The outer diameter of the fixing ring 13 is larger than the inner diameter of the outer ring 14 of the protective cap, and the height of the fixing ring 13 is adapted to the height of the locking ring 15. The fixing ring 13 has a fixing thread 16 inside.

[0039] The protective cap 4 consists of an inner protective cap ring 17 and an outer protective cap ring 14.

[0040] The outer wall of the inner ring 17 of the protective cap is provided with a protective cap thread 18 that matches the thread 12 of the fixing cylinder. The protective cap 4 can be stably installed on the fixing cylinder 11 through the thread engagement. The inner ring 17 of the protective cap is ultrasonically welded, or the filter element 10 can be directly fixed to the inner ring 17 of the protective cap. The filter element 10 is made of medical grade hydrophilic polyethersulfone filter membrane. Its outer diameter matches the inner diameter of the retaining ring 9 on the inner wall of the cone head 5. The edge of the filter element 10 is provided with an annular protrusion that engages with the retaining ring 9 to ensure that the filter element 10 can be stably embedded in the retaining ring 9.

[0041] The outer ring 14 of the protective cap has a locking ring 15 at the bottom. The locking ring 15 and the outer ring 14 of the protective cap are integrally formed with four evenly distributed easy-break points 19. The fracture strength of the easy-break points 19 is less than the threaded connection strength between the inner ring 17 of the protective cap and the fixing cylinder 11. The inner wall of the locking ring 15 is provided with threads that are compatible with the fixing threads 16 inside the fixing ring 13.

[0042] The usage process of this embodiment is as follows:

[0043] 1. High-pressure sterilization stage: The assembled 0.9% sodium chloride pre-filled syringe is subjected to high-pressure sterilization. Due to the tight fit between the protective cap thread 18 of the inner ring 17 of the protective cap and the fixed cylinder thread 12 of the fixed cylinder 11, and the cooperation between the fixed ring 13 of the fixed cylinder 11 and the locking ring 15 of the protective cap 4, the protective cap 4 can be effectively prevented from falling off during the sterilization process, thus ensuring a sterile environment inside the syringe.

[0044] 2. Preparation stage: Medical staff hold the sleeve 3 and rotate the outer ring 14 of the protective cap. Since the fracture strength of the easy breakage point 19 is low, and the locking thread 20 of the locking ring 15 is engaged to ensure that the locking ring 15 will not rotate with the outer ring 14 of the protective cap, the external force of rotation will first cause the easy breakage point 19 to break. The locking ring 15 will disengage from the outer ring 14 of the protective cap and will be retained on the outside of the fixing ring 13 through the engagement of the locking thread 20 with the fixing thread 16 of the fixing ring 13.

[0045] 3. Filter structure activation stage: Continue to rotate the outer ring 14 of the protective cap. The outer ring 14 of the protective cap drives the inner ring 17 of the protective cap to rotate and move outward relative to the cone head 5. The filter element 10 inside the inner ring 17 of the protective cap will be blocked by the retaining ring 9 on the inner wall of the cone head 5. As the rotation continues, the inner ring 17 of the protective cap separates from the filter element 10. The filter element 10 is engaged in the retaining ring 9 by the annular protrusion 21, thus completing the activation of the filter structure.

[0046] 4. Injection and use stage: Connect the catheter connector to the cone 5, push the core rod 1, and the piston 2 moves within the sleeve 3 to push the injection solution into the catheter. During this process, the injection solution will be filtered by the filter element 10 to remove any possible microparticles and microorganisms, ensuring medication safety. After use, medical staff can quickly determine whether the syringe has been used by observing whether there is a locking ring 15 at the fixing ring 13, or whether the easily breakable point 19 between the locking ring 15 and the outer ring 14 of the protective cap is broken, thus avoiding secondary misuse.

Claims

1. A pre-filled flushing syringe with filtering, anti-cap removal, and anti-reuse functions, characterized in that, The pre-filled flushing syringe includes a core rod, a piston, a sleeve, and a protective cap. The piston is assembled inside the sleeve, and one end of the core rod is fixedly connected to the piston. The top of the sleeve has an integrally formed cone for connecting a catheter connector. A retaining ring is provided circumferentially on the inner wall of the cone. The retaining ring is a raised or recessed annular structure, and the number of retaining rings is 1-3. A fixing cylinder is coaxially fixed to the outer side of the sleeve cone. The inner wall of the fixing cylinder has a fixing cylinder thread, and the outer wall of the fixing cylinder has a fixing ring and fixing threads circumferentially. The protective cap consists of an inner protective cap ring and an outer protective cap ring. The outer wall of the inner protective cap ring has threads that match the fixing cylinder thread. The protective cap has a threaded design, and a filter element is nested within the inner ring of the protective cap. The filter element has a pore size of 0.22-5µm. The filter element is separable from the inner ring of the protective cap. The filter element has an annular groove or annular protrusion that matches the retaining ring on the inner wall of the cone head. The annular groove or annular protrusion can engage with the retaining ring, so that the filter element is fixed inside the cone head after being separated from the inner ring of the protective cap. The inner ring of the protective cap and the separable filter element are fixedly connected by ultrasonic welding, or directly fixed to the inner side of the inner ring of the protective cap without welding. The bottom of the outer ring of the protective cap has a locking ring, which is connected to the outer ring of the protective cap through a breakable point. The inner wall of the locking ring has locking threads that match the fixing threads.

2. A pre-filled flushing syringe with filtering, anti-cap removal, and anti-reuse functions according to claim 1, characterized in that, The fixed cylinder and sleeve are integrally injection molded, and the raw materials are one or more of polypropylene (PP), polyethylene (PE) or cyclic polyolefin (COC). The piston material is one or more of polyisoprene rubber, butyl rubber, halogenated butyl rubber, silicone rubber, and EPDM rubber. The core rod and protective cap are made of one or more of PP, PE or COC.

3. A pre-filled flushing syringe with filtering, anti-cap removal, and anti-reuse functions according to claim 1, characterized in that, The filter element raw material is one or more of polyethersulfone, nylon, or mixed cellulose esters.

4. A pre-filled flushing syringe with filtering, anti-cap removal, and anti-reuse functions according to claim 1, characterized in that, The pitch between the thread of the protective cap and the thread of the fixed cylinder is 0.5-1mm, and the thread mating length is 5-8mm.

5. A pre-filled flushing syringe with filtering, anti-cap removal, and anti-reuse functions according to claim 1, characterized in that, The outer wall of the outer ring of the protective cap is provided with anti-slip texture; the anti-slip texture is one of diamond pattern, stripe pattern or grid pattern.

6. A pre-filled flushing syringe with filtering, anti-cap removal, and anti-reuse functions according to claim 1, characterized in that, The fixing ring on the outer wall of the fixing cylinder can be a raised or recessed design, and the fixing thread can be located on or below the fixing ring.

7. A pre-filled flushing syringe with filtering, anti-cap removal, and anti-reuse functions according to claim 1, characterized in that, The number of easily fractured points is 2-10, and they are evenly distributed along the circumferential direction of the mating surface between the outer ring of the protective cap and the locking ring. The fracture strength of the easily fractured points is less than the threaded connection strength between the inner ring of the protective cap and the fixed cylinder.

8. A pre-filled flushing syringe with filtering, anti-cap removal, and anti-reuse functions according to claim 1, characterized in that, The locking thread and the fixing thread can engage with each other. During the tightening of the protective cap, the locking thread can slide relative to the fixing thread. During the unscrewing of the protective cap, the locking thread and the fixing thread lock together to prevent the locking ring from rotating with the protective cap, thereby causing the locking ring to detach from the protective cap.

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