Medical built-in filter

Abstract

The invention discloses a medical built-in filter which comprises an upper connecting pipe, an outer shell and an inner shell which are sequentially connected in an elastic sealing mode and are detachable. A one-way filtering device is arranged on the inner shell; and a filtering membrane is arranged in a cavity formed between the inner shell and the outer shell. According to the medical built-in filter, the one-way filtering device is arranged on the inner shell; the filter membrane is arranged in the cavity formed between the inner shell and the outer shell, a two-layer filter structure is formed, liquid backflow is prevented, meanwhile, liquid medicine can be effectively filtered in two times, falling scraps and insoluble particles generated by long-term contact of a medical injector and the liquid medicine can be filtered, and therefore the medical injector is prevented from being damaged. The filtered impurities are blocked and prevented from entering the human body along with the filtrate again, so that the safety and the quality controllability of medication are improved.

Description

Technical Field

[0001] The invention relates to the field of medical filters, in particular to a medical built-in filter. Background Art

[0002] Pharmaceutical packaging materials refer to the outer packaging materials and pharmaceutical filling materials used to protect and store and directly contact drugs, referred to as pharmaceutical packaging materials. Qualified pharmaceutical packaging materials need to have four basic elements. First, they must protect drugs throughout the entire process of drug research and development, production, circulation, and use, and prevent drugs from being affected by factors such as light, absorption / loss of water, reactive gases (oxygen) and microorganisms; second, they must have good compatibility with drugs, and there must be no interaction between their packaging components and preparations, which would cause changes in the quality of preparations or pharmaceutical packaging material components, including concentration changes caused by the adsorption of active ingredients or excipients of drugs by packaging materials, degradation of active ingredients caused by packaging material extracts, and pH changes, precipitation, discoloration, etc.; third, the safety of raw materials used to produce pharmaceutical packaging material components, which must not contain substances that are harmful to the human body and can migrate to drugs, so the focus should be on components that are in direct contact with drugs; fourth, the functionality of pharmaceutical packaging materials, which need to provide the correct dosage conveniently and accurately.

[0003] The properties of the raw materials of the drug packaging materials that are in direct contact with the drug are important factors affecting the safety of medication and the shelf life of the drug. For example, the raw materials commonly used for drug packaging materials such as syringes, infusion bags and ampoules are glass, polymer resin, rubber, metal, etc., and can also be composed of two or more materials (such as composite films, aluminum-plastic composite covers, etc.). After long-term contact with drugs, drug packaging materials will produce debris and insoluble particles suspended in the drug solution, which has hidden dangers to the quality of drugs and the human body (routine inspections cannot be discovered in time). Among them, polymer resin packaging occupies a large proportion in the field of drug packaging. It has the advantages of firm packaging, easy sealing, transparent and beautiful, light weight, easy to carry, and low price. However, after long-term contact with drugs, the degradation products of polymer resin will migrate into the drugs, and there are risks of high temperature, high pressure, ultraviolet radiation and shock during transportation, which will accelerate the aging and degradation of plastics, cause structural changes such as cross-linking or breaking of molecular chains, and produce more migration products, affecting the quality of drugs. The advantages of glass pharmaceutical packaging materials are transparency, easy sealing, moisture resistance and relatively stable chemical properties, but they are heavy and fragile. After contact with drugs, glass flakes will migrate into the drugs to form glass fragments, which may cause tissue inflammation and damage immune cells during administration, and even have the hidden danger of blocking blood vessels and forming blood clots. In addition to producing degradation products and additives, rubber pharmaceutical packaging materials will also produce rubber particles during perforation, and the smaller the particle size, the stronger the penetration ability, which seriously affects the safety and quality controllability of medication.

[0004] On the other hand, bubbles often exist in the liquid during intravenous infusion or syringe infusion. If a large amount of air enters the human body in a short period of time, the blood in the heart cavity will be stirred by the beating of the human heart, which will produce a large number of bubbles. When the heart contracts, the bubbles are not discharged or block the pulmonary artery, which will pose a serious threat to human health and even cause sudden death. If the gas enters the coronary artery of the heart, it may also cause coronary circulation obstruction, which will hinder the heart function of the person and threaten people's lives. Therefore, small bubbles in the liquid should be removed in time during use or treatment. The prefilled syringe is a closed structure. At present, the "retained bubble technology" is often used. When injecting, it is directly injected without exhausting. When all the liquid is injected, the small bubbles in the syringe are just filled at the front end of the syringe. This puts forward higher standards and requirements for the syringe production and liquid filling process.

[0005] For example, Chinese patent document CN104174101A discloses a silicone-free prefilled syringe, which only includes a medicine bottle and a Luer connector, which can prevent silicone oil or other lubricants from contaminating the medicine and can smoothly complete the injection. Although the quality of the medicine in the syringe will not be affected by silicone oil, it has no filtering effect on the migration produced by the tube body.

[0006] Chinese patent document CN105056329A discloses a drug dissolving device, including a needle holder, a cannula and a needle, which plays a role in filtering impurities during the process of drug inhalation and extrusion. However, when the drug dissolving device performs the inhalation and extrusion actions, the impurities are filtered by the filter membrane and remain on the upper side, and migrate into the drug solution again during the extrusion, and the impurities in the drug solution are not substantially filtered.

[0007] Chinese patent document CN105708693A discloses a syringe filter needle, whose filter layer is composed of a baffle, a liquid medicine filter membrane and an elastic one-way valve membrane arranged on both sides of the baffle, the liquid medicine filter membrane is arranged on one side of the baffle close to the syringe barrel, and the one-way valve membrane is close to the other side of the baffle and has multiple disconnection lines in the middle. However, the syringe filter needle is an external filter, and when in use, the syringe needle needs to be removed and the filter installed at the connection between the syringe body and the needle, which may cause particles, bacteria, etc. in the air to contaminate the liquid medicine and enter the human blood circulation with the liquid medicine, causing adverse reactions to infusion and potential complications.

[0008] Chinese patent document CN202409629U discloses a breast pump, which has different suction ports and exhaust ports, and the suction direction and exhaust direction do not belong to the same through hole, which can effectively achieve continuous and rapid suction and exhaust, and the vacuum in the breast cup is generated efficiently, thereby improving the effect of milk suction. However, the device has great limitations when used for medicines, has a narrow application range, and cannot achieve fine control.

[0009] Chinese patent document CN201267678Y discloses a disposable one-way valve for infusion, including a valve seat, a valve cover, and a cut-off diaphragm. A cavity is formed between the valve seat and the valve cover, and the inside of the cavity is a cut-off diaphragm. The one-way valve can prevent the drug solution from returning to the drip bucket during the drug addition operation, so that the added drug solution can quickly enter the blood without being diluted by the drug. However, the one-way valve is an external drug filter, which needs to be assembled with other infusion devices during use, and there is a risk of introducing bacteria and impurities.

[0010] Chinese patent document CN207221116U discloses an obstetric cleaning device, including a funnel-shaped shield, a medicine inlet pipe, a medicine liquid bag and a sponge, wherein a one-way flow control valve for controlling the one-way flow of the medicine liquid is arranged in the medicine inlet pipe, and the one-way flow control valve includes a hard baffle and a soft baffle. However, the device has great limitations and a narrow application range, and its one-way flow control valve only prevents the liquid from flowing back, and has no filtering effect. Summary of the invention

[0011] In view of the problems existing in the prior art and the areas that need improvement, the present invention provides a medical internal filter to solve the problems that most existing filters cannot effectively filter impurities; or can only be used as external filters, which may introduce bacteria or impurities and pose safety hazards.

[0012] To achieve the above purpose, the present invention adopts the following technical methods:

[0013] A medical internal filter comprises an upper connecting tube, an outer shell and an inner shell which are sequentially connected by elastic sealing and are detachable;

[0014] The inner shell is provided with a one-way filtering device;

[0015] A filter membrane is arranged in the cavity formed between the inner shell and the outer shell.

[0016] Optionally, the portion of the upper connecting tube extending into the interior of the outer shell forms a bubble retaining ring, and a gas storage cavity is formed between the bubble retaining ring, the outer shell and the filter membrane. During use, bubbles mixed into the medicine solution will preferentially enter the interior thereof, thereby preventing bubbles from entering the body along with the medicine solution.

[0017] Optionally, the one-way filtering device includes a liquid channel and an elastic one-way valve for controlling the flow direction of the liquid channel; preferably, the elastic one-way valve includes a circular baffle and a groove matching the circular baffle (when closed, the circular baffle is placed in the groove matching the circular baffle on the inner shell), and the cross-sectional radius of the circular baffle is larger than the cross-sectional radius of the liquid channel; the circular baffle is coaxial with the liquid channel.

[0018] The diameter and density of the liquid channel on the inner shell can be adjusted according to actual needs, and each liquid channel is correspondingly provided with an elastic one-way valve for controlling its flow direction. The one-way filter device on the inner shell is the first filter layer, which can filter out impurity particles with a particle size larger than the diameter of the liquid channel. The filter membrane is the second filter layer in the process of filtering the liquid medicine, and the particle size of the impurity particles filtered is smaller than the diameter of the liquid channel. Filter membranes with different filtering performances can be selected according to actual needs.

[0019] Optionally, the upper connecting tube is a T-shaped tube, comprising a top tube body, a cylindrical tube body and a conical tube body that are coaxial (the axes are on the same straight line) and sealed connected in sequence, and the inner diameter of the top tube body is the same as the inner diameter of the cylindrical tube body, the thickness of the top tube body is greater than the thickness of the cylindrical tube body, and the protruding part is used to fix the filter to prevent it from slipping.

[0020] Optionally, the conical tube body is elastically sealed to the outer shell.

[0021] Optionally, the top tube body of the upper connecting tube is connected to the cylindrical tube body of the upper connecting tube by a buckle.

[0022] Optionally, the cylindrical tube body and the conical tube body are an integral structure, the conical tube body is a truncated cone-shaped cavity with one end larger than the other end, and the inner wall of the truncated cone-shaped cavity of the conical tube body is smoothly connected to the inner wall of the cylindrical tube body.

[0023] Optionally, the outer shell includes a circular ring on the top and a side wall on the bottom, and the circular ring is sealed to the side wall; the filter membrane is fixed in a cavity formed by the outer shell and the inner shell; preferably, the filter membrane is fixed in the cavity formed by the outer shell and the inner shell by a U-shaped supporting structure; more preferably, the U-shaped supporting structure is two U-shaped seats, each of which has a U-shaped hollow cavity, and both ends of the filter membrane are respectively embedded in the U-shaped hollow cavities of the two U-shaped seats, and the U-shaped supporting structure is an elastomer.

[0024] Optionally, an annular protrusion is provided at the connection between the top circular ring of the outer shell and the side wall, and the annular protrusion is located in the cavity formed by the outer shell and the inner shell;

[0025] An elastic sealing ring is provided at the contact point between the inner shell and the bottom side wall of the outer shell;

[0026] The annular protrusion and the elastic sealing ring cooperate with each other to fix the filter membrane and the U-shaped supporting structure for fixing the filter membrane in the cavity formed between the outer shell and the inner shell, that is, the annular protrusion and the elastic sealing ring are in contact with the surface of the U-shaped supporting structure respectively.

[0027] Optionally, the conical tube body is connected to the circular ring on the top of the outer shell by a threaded structure; preferably, an external thread is provided on the outer wall of the conical tube body, and an internal thread is provided on the inner wall of the top circular ring, and the internal thread cooperates with the external thread to form a thread pair.

[0028] Optionally, the height of the external thread and the internal thread (i.e., the height of the thread teeth) are both less than the thickness of the conical tube body, and the screwing length of the external thread and the internal thread is less than the length of the outer wall generatrix of the conical tube body (i.e., at least one thread tooth). When the internal thread and the external thread cooperate to form a thread pair, the top, bottom, and side of the thread teeth are all subjected to force. After the threads are tightened, the thread pair itself has a sealing ability to prevent the drug liquid from flowing out of the thread gap when squeezed. The shapes of the external thread and the internal thread are not specifically limited, and conventional shapes are sufficient, such as trapezoidal, rectangular, or serrated.

[0029] Optionally, the inner shell is an elastomer, and the inner shell is sealed and connected to the side wall at the bottom of the outer shell by a snap-on buckle to fix the inner shell; preferably, an annular barbed buckle is provided at the bottom of the side wall of the outer shell for fixing the inner shell, and the outer diameter of the inner shell matches the inner diameter of the side wall of the outer shell and the inner shell is inserted into the inside of the side wall of the outer shell.

[0030] Optionally, two slots are provided on the outer wall edge of the top tube body of the upper connecting tube, and the two slots are symmetrically arranged; two slots are provided on the bottom of the side wall of the outer shell, and the two slots are symmetrically arranged. The upper connecting tube and the outer shell are fixed respectively through the two symmetrically arranged slots by means of an external tool such as a wrench, and then the upper connecting tube and the outer shell are respectively rotated along the direction of the threaded assembly, thereby fixing the upper connecting tube and the outer shell.

[0031] Working principle: Figure 7As shown, the built-in filter is first placed inside the syringe, and the specific steps are as follows: first, the upper connecting tube of the built-in filter is placed in the syringe cone head, and the upper connecting tube of the built-in filter is fixed to prevent slipping by using the protruding part of the top tube body whose thickness is greater than the thickness of the cylindrical tube body, but the thickness of the protruding part should not exceed the thickness of the syringe cone head used. Secondly, the outer shell of the built-in filter is placed through the bottom of the syringe barrel, and the outer shell is rotated by two symmetrical slots at the bottom of the side wall of the outer shell with the help of external tools such as wrenches, and the upper connecting tube is rotated by two symmetrical slots on the upper connecting tube with the help of external tools such as wrenches, which can be clockwise or counterclockwise, and the rotation direction is determined by the internal thread on the inner wall of the outer shell top ring and the external thread on the outer wall of the cone tube body at the bottom of the upper connecting tube, thereby connecting the upper connecting tube to the outer shell, and the thread pair is a self-locking structure with a sealing function. Finally, the filter membrane and the inner shell are placed in sequence from the bottom of the syringe barrel, and the inner shell position is fixed by the locking barbs at the bottom of the outer shell to prevent it from falling off. Thus, the filter is placed inside the syringe.

[0032] After the built-in filter is assembled in the syringe, the liquid medicine is poured into the syringe barrel from the bottom of the syringe barrel. When the syringe push rod applies pressure from the bottom of the syringe barrel to the top, the liquid medicine is pushed out from the syringe barrel to the cone head. When the liquid medicine flows through the filter, the liquid medicine first acts on the inner shell, enters from the bottom of the inner shell, and under the action of atmospheric pressure and the flow force of the liquid medicine, the one-way filter device is opened and the liquid medicine is initially filtered. Then the liquid medicine is filtered twice through the filter membrane and flows into the upper connecting tube. The filter membrane can remove impurities with smaller particle sizes and leave them on the side of the filter membrane close to the inner shell. On the contrary, when the liquid medicine located on the side of the filter membrane close to the upper connecting tube enters the syringe from the cone head direction, under the action of atmospheric pressure and the flow force of the liquid medicine, the one-way filter device on the inner shell is closed to prevent the liquid medicine poured into the syringe from being contaminated.

[0033] Specifically, when the liquid medicine is pushed out from the syringe toward the cone head, the liquid medicine acts on the inner shell, first entering the liquid channel from the bottom of the inner shell, under the action of atmospheric pressure and the flow force of the liquid medicine, the circular baffle is flushed open, the one-way valve is opened, and the liquid channel on the inner shell performs a preliminary filtration on the liquid medicine, filtering out impurities with a particle size larger than the diameter of the liquid channel, and then the liquid medicine flows into the upper connecting tube after secondary filtration through the filter membrane, and the filter membrane can remove impurities with a smaller particle size and leave them on the side of the filter membrane close to the inner shell. The medical built-in filter provided by the present invention adopts a two-layer liquid medicine filtration structure to filter the liquid medicine in sequence and retain the filtered impurities on the side away from the upper connecting tube, and no longer enters the human body with the liquid medicine, thereby filtering the liquid medicine. On the contrary, when the liquid medicine located on the side of the filter membrane close to the upper connecting tube enters the syringe from the cone head direction, under the action of atmospheric pressure and the flow force of the liquid medicine, the circular baffle of the one-way valve on the inner shell is embedded and tightly fastened in the groove matched with it, and the valve of the one-way valve is closed.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The medical built-in filter provided by the present invention has a one-way filtering device on the inner shell; and a filtering membrane is arranged in the cavity formed between the inner shell and the outer shell to form a two-layer filtering structure. While preventing the liquid from flowing back, the drug liquid can be effectively filtered twice, and the debris and insoluble particles generated by the long-term contact between the medical syringe and the drug liquid can be filtered, and the filtered impurities can be blocked to prevent them from entering the human body again with the filtrate, thereby improving the safety of drug use and the controllability of quality.

[0036] 2. The medical internal filter provided by the present invention has the advantages of multi-layer filtration, simple structure, reliable connection, and convenient assembly and disassembly. It can filter the liquid medicine flowing out of the syringe and retain the filtered impurities in the syringe, which can effectively prevent the insoluble particles in the medicine from contaminating the liquid medicine and entering the human blood circulation with the liquid medicine, and plays a substantial filtering role on the liquid medicine. Moreover, the medical internal filter has low production cost and is easy to use. It can be used as a part of the syringe assembly and matched with the syringe to be installed at the liquid medicine outlet, effectively ensuring the safety of medication and effectively extending the shelf life of the medicine.

[0037] 3. The medical built-in filter provided by the present invention extends the upper connecting tube into the interior of the outer shell so that the extended part forms a bubble retaining ring, and a gas storage cavity is formed between the bubble retaining ring, the outer shell and the filter membrane, thereby preventing bubbles in the medicine liquid from entering the human body along with the liquid during use and causing harm.

[0038] 4. The advantage of prefilled syringes as third-generation syringes is that the liquid medicine can be injected into the syringe in advance for storage and transportation. The syringe is a fully sealed structure before use, which can effectively prevent the liquid medicine from being exposed to the air and contaminated. Most prefilled syringes use an integrated needle, which cannot cooperate with the existing external filter to filter the liquid medicine. The connection method between the external filter and the syringe used in the prior art is nested. If assembled during use, it is still impossible to avoid the liquid medicine from contacting with the air. If it is assembled as part of the syringe assembly and then used, it is easy to fall off during transportation; and the liquid medicine with high viscosity will usually detach from the syringe due to the high internal pressure during the injection process. The built-in filter provided by the present invention tightly connects the syringe barrel and the filter through the sealing pipe thread, effectively preventing the filter from falling off, and completely preventing air from contacting the liquid medicine; it is not only applicable to existing prefilled syringes, but also to first-generation glass syringes and second-generation sterile plastic syringes. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the structure of a medical internal filter provided by the present invention;

[0040] Figure 2 for Figure 1 A cross-sectional view of a built-in filter used in traditional Chinese medicine;

[0041] Figure 3 for Figure 1 A cross-sectional view of the connection between the middle upper connecting pipe and the outer shell;

[0042] Figure 4 for Figure 1 A top view of the inner shell;

[0043] Figure 5 for Figure 1 A schematic diagram of the structure of the liquid channel in the inner shell;

[0044] Figure 6 for Figure 1 Schematic diagram of the connection between the circular baffle and the liquid channel on the inner shell;

[0045] Figure 7 This is a schematic diagram of the application of the built-in filter provided by the present invention in a syringe.

[0046] In the figure:

[0047] 1. Upper connecting tube; 2. Outer shell; 3. Filter membrane; 4. Inner shell; 5. Built-in filter; 6. Syringe; 11. Top tube body; 12. Cylindrical tube body; 13. External thread; 14. Bubble retaining ring; 21. Circular ring; 22. Side wall; 31. U-shaped seat; 41. Elastic sealing ring; 42. Liquid channel; 61. Conical head; 62. Syringe; 63. Push rod; 111. Slot; 211. Internal thread; 212. Annular protrusion; 213. Gas storage chamber; 221. Barb buckle; 222. Slot; 421. Open end; 422. Circular retaining plate; 423. Groove; 424. Connection. DETAILED DESCRIPTION

[0048] The following is a detailed description of the embodiments of the present invention: This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and process are given, but the protection scope of the present invention is not limited to the following embodiments. The experimental methods in the following embodiments without specifying specific conditions are usually carried out under conventional conditions.

[0049] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by terms such as “upper”, “lower”, “inside”, “outside”, “top” and “bottom” are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0052] like Figure 1-Figure 6 The figure shows a specific implementation of the medical built-in filter provided by the present invention.

[0053] like Figure 1 As shown, the medical internal filter includes: an upper connecting tube 1, an outer shell 2, a filter membrane 3 and an inner shell 4. The components are connected by elastic sealing and are detachable to avoid leakage during the filtration process and are easy to assemble; a one-way filtering device is provided on the inner shell 4 to prevent the backflow of the drug solution; the filter membrane 3 is located in the cavity formed between the inner shell 4 and the outer shell 2.

[0054] This medical built-in filter can filter the drug solution twice and prevent the drug solution from flowing back. At the same time, it can retain the filtered impurities in the syringe, effectively preventing insoluble particles in the drug from contaminating the drug solution and entering the human blood circulation with the drug solution, thus playing a substantial filtering role on the drug solution.

[0055] Specifically, the upper connecting tube 1 is a T-shaped tube body, including a top tube body 11, a cylindrical tube body 12 and a conical tube body (not shown in the figure) whose axes are on the same straight line, and the top tube body 11 and the cylindrical tube body 12 are fixedly connected by a buckle.

[0056] The upper connecting tube 1 has a circular cross section, the inner wall cross section diameter of the top tube body 11 is the same as the inner wall cross section diameter of the cylindrical tube body 12, the thickness of the top tube body 11 is greater than the thickness of the cylindrical tube body 12, and the protruding portion is used to fix the filter to prevent it from slipping, but the thickness of the protruding portion should not exceed the thickness of the cone head of the syringe used. The lower end of the cylindrical tube body 12 is connected to the upper end of the conical tube body, and the conical tube body is a truncated cone-shaped cavity with one end larger and the other end smaller, and the inner wall of the truncated cone-shaped cavity of the conical tube body is smoothly connected to the inner wall of the cylindrical tube body 12.

[0057] The outer shell 2 includes a circular ring 21 at the top and a side wall 22 at the bottom, and the circular ring 21 and the side wall 22 are sealed and connected; the circular ring 21 and the side wall 22 can be an integral structure or can be sealed and connected in other ways.

[0058] An external thread 13 is provided on the outer wall of the conical tube body, and an internal thread 211 is provided on the inner wall of the ring 21 at the top of the outer shell 2. The internal thread 211 cooperates with the external thread 13 to form a thread pair to connect the upper connecting pipe 1 and the outer shell 2 together, and the external thread 13 and the internal thread 211 are both trapezoidal single-line threads (that is, the protruding tooth profile on the cross section of the thread is trapezoidal, the external thread 13 is a spiral line formed along the outer wall of the conical tube body, and the internal thread 211 is a spiral line on the outer shell 2 that cooperates with the external thread 13, which can be left-handed or right-handed (such as Figure 3As shown), the difference between the major diameter r1 and the minor diameter r2 of the thread is less than twice the thickness of the conical tube body (that is, the height of the thread tooth is less than the thickness of the conical tube body), and the screwing length of the external thread and the internal thread is less than the length of the outer wall generatrix of the conical tube body (that is, the thread contains one tooth at the top, and the more teeth there are, the better the sealing performance). During operation, the top, bottom and sides of the thread teeth are all subjected to force. After the thread is tightened, the deformation of the thread teeth makes the formed thread pair itself have sealing ability, which can prevent the liquid from flowing out of the thread gap when squeezed. The upper connecting tube 1 and the outer shell 2 are connected by this thread structure. During the threaded assembly process of the external thread 13 and the internal thread 211, the upper connecting tube 1 and the outer shell 2 are fixed through the slots with the help of two symmetrical grooves 111 set on the outer wall edge of the top tube body of the upper connecting tube 1 and two symmetrical grooves 222 set at the bottom end of the side wall 22 of the outer shell 2 with the help of external tools such as wrenches, and the upper connecting tube 1 and the outer shell 2 are fixedly connected along the direction of the thread pair formed by the external thread and the internal thread (as shown in the figure). Figure 2 shown).

[0059] The portion of the conical tube extending into the outer shell 2 forms a bubble retaining ring 14, and a gas storage cavity 213 (such as Figure 1 and Figure 3 As shown in the figure, bubbles flow into the gas storage chamber from the gap between the bubble retaining ring and the filter membrane. During use, bubbles mixed in the medicine solution will preferentially enter the interior of the gas storage chamber, preventing bubbles from entering the body with the medicine solution.

[0060] The bottom of the side wall 22 at the bottom of the outer shell 2 is provided with an annular barb buckle 221 (such as Figure 2 As shown). The inner shell 4 is an elastic body, and the outer diameter of the inner shell 4 matches the inner diameter of the side wall 22 of the outer shell 2, and the inner shell 4 is inserted into the side wall 22 of the outer shell 2. Specifically, the inner shell 4 is inserted into the side wall 22 of the outer shell 2 and fixed by the annular barb buckle 221. When the inner shell is pushed in, the barb is deformed, and the tip is bent close to the top of the outer shell. When the bottom edge of the inner shell enters the cavity of the outer shell, the barb recovers the deformation and fixes the position of the inner shell. The barb angle should be appropriate. When the drug liquid flows into the syringe from the direction of the cone head, the barb should be able to support the inner shell, and the inner shell will not move into the syringe and separate from the outer shell. The length of the barb should not cover the opening end of the liquid channel on the inner shell to reduce the liquid flow rate.

[0061] The filter membrane 3 is fixed in the cavity formed between the inner shell 4 and the outer shell 2 by a U-shaped supporting structure. The U-shaped supporting structure is two elastic U-shaped seats 31 with U-shaped hollow cavities. The two ends of the filter membrane 3 are respectively embedded in the U-shaped hollow cavities of the two elastic U-shaped seats 31. The U-shaped hollow cavity cooperates with the filter membrane 3, and the opening height and depth of the U-shaped hollow cavity are highly matched with the cross-sectional diameter of the edge of the filter membrane 3. The two ends of the filter membrane 3 are respectively embedded in the U-shaped hollow cavities of the two elastic U-shaped seats 31.

[0062] An annular protrusion 212 is provided at the connection between the top ring 21 of the outer shell 2 and the side wall 22, and an elastic sealing ring 41 is provided at the connection between the inner shell 4 and the bottom side wall 22 of the outer shell 2. The annular protrusion 212 and the elastic sealing ring 41 fix the filter membrane 3 and the U-shaped supporting structure for fixing the filter membrane 3 in the cavity between the outer shell 2 and the inner shell 4, and the elastic sealing ring can prevent the drug solution from flowing out of the gap between the filter membrane and the inner side of the outer shell when squeezed, and plays a supporting role for the filter membrane structure.

[0063] The one-way filtering device on the inner shell 4 includes a liquid channel 42 (such as Figure 4 As shown), and an elastic one-way valve for controlling the flow direction of the liquid channel 42; the elastic one-way valve includes a circular baffle 422, and a groove 423 (as shown) matching the circular baffle 422 Figure 5 As shown in FIG. 4 ), the circular baffle 422 is coaxial with the liquid channel 42, and the cross-sectional radius of the circular baffle 422 is greater than the cross-sectional radius of the liquid channel 422. The liquid channel 422 has an open end 421 and a sealed end. A groove 423 is provided in the inner shell 4 at the sealed end of the liquid channel 422. The groove 423 matches the edge of the lower surface of the circular baffle 422 and forms a connection 424 (as shown in FIG. Figure 6 As shown in the figure, the smaller the connection part (i.e., the connection point) between the circular baffle and the inner shell is, the easier it is for the connection part between the circular baffle and the inner shell to bend and open when subjected to the force of the liquid medicine flowing from the syringe to the needle. In the specific implementation process, the density and size of the liquid channels distributed on the inner shell should be appropriate (the layout density of the liquid channels on the inner shell and the cross-sectional radius of the liquid channels can be adjusted according to actual needs, and each liquid channel corresponds to an elastic one-way valve). The circular baffle is made of elastic material, and its thickness and elasticity should be appropriate, which can ensure that when not subjected to external force, the circular baffle must be in a completely closed state where liquid cannot flow through, that is, the baffle must be embedded and tightly fastened in the groove, and the gap between it and the contact surface of the groove must be extremely small or even close to zero, and it must also ensure that when subjected to the force of the liquid medicine flowing from the injection syringe to the cone head, the connection can be relatively easy to bend and open to form a gap.

[0064] like Figure 7As shown, when the above-mentioned medical built-in filter 5 is used in combination with the syringe 6 for filtering, the built-in filter 5 is assembled inside the syringe 6 before the liquid is pre-filled in the syringe. Specifically, first, the upper connecting tube of the built-in filter 5 is placed in the syringe cone 61, and the protruding part of the top tube body of the upper connecting tube is used to fix the filter upper connecting tube to prevent slipping, but the thickness of the protruding part should not exceed the thickness of the syringe cone head used. Secondly, the outer shell of the built-in filter is placed through the bottom of the syringe barrel 62, and the upper connecting tube 1 and the outer shell 2 are fixed and rotated by means of external tools such as wrenches through the slots to achieve fixed connection between the upper connecting tube 1 and the outer shell 2, and the specific rotation direction is determined by the internal thread on the inner wall of the top ring of the outer shell and the external thread on the outer wall of the conical tube body at the bottom of the upper connecting tube, and the thread pair formed by rotation is a self-locking structure with a sealing function. Next, a filter membrane containing two U-shaped seats is placed from the bottom of the syringe barrel (i.e., the two sections of the filter membrane are respectively embedded in the U-shaped hollow cavity of the two elastic U-shaped seats), so that the annular protrusion at the connection between the top circular ring of the outer shell and the side wall, and the elastic sealing ring at the contact between the top of the inner shell and the bottom side wall of the outer shell cooperate with each other to fix the filter membrane fixed by the U-shaped support structure in the cavity formed between the outer shell and the inner shell. Finally, the inner shell is placed from the bottom of the syringe barrel, and an elastic sealing ring is placed at the connection between the inner shell and the bottom side wall of the outer shell, and the position of the inner shell is further fixed by the locking barbs located at the bottom of the outer shell to prevent it from falling off. Thus, the filter is placed inside the syringe.

[0065] The outer diameter of the cylindrical body should be slightly smaller than the inner diameter of the syringe cone, so that the cylindrical body can be completely fitted with the inner wall of the syringe cone. The outer diameter of the top ring and the bottom side wall of the outer shell should be slightly smaller than the inner diameter of the syringe barrel, so that the top ring and the bottom side wall of the outer shell can be completely fitted with the inner wall of the syringe barrel. The specifications of the built-in filter can be adjusted accordingly according to the specifications of the syringe used.

[0066] After the above-mentioned medical built-in filter is assembled in the syringe, the liquid medicine is poured into the syringe barrel from the bottom of the syringe. When the push rod 63 applies pressure from the bottom of the syringe toward the cone head (the direction of the arrow in the figure), the liquid medicine is pushed out from the syringe barrel toward the cone head. When the liquid medicine flows through the filter, the liquid medicine first acts on the inner shell body and enters the open end of the liquid channel from the bottom of the inner shell body. Under the action of atmospheric pressure and the flow force of the liquid medicine, the circular baffle at the sealing end of the liquid channel is opened, and the part of the circular baffle that is not connected to the inner shell body is formed to allow the liquid medicine to flow The gap is opened, the one-way valve opens, and the liquid medicine enters the cavity between the inner shell and the filter membrane. During this process, the channel on the inner shell performs preliminary filtration on the liquid medicine, and retains impurities with larger particle sizes on the side of the inner shell close to the injection barrel; then the liquid medicine flows into the upper connecting tube through the filter membrane. At this time, the filter membrane can filter impurities with smaller particle sizes and retain them on the side of the filter membrane close to the inner shell, and the bubbles carried in the liquid medicine can enter the gas storage cavity after passing through the filter membrane, and are prevented from entering the upper connecting tube by the bubble retaining ring to prevent the bubbles from being discharged with the liquid medicine. During the filtration process, due to external pressure, the upper elastic sealing ring of the inner shell is pressed against the lower surface of the U-shaped support structure, and the upper surface of the U-shaped support structure is pressed against the top of the annular protrusion on the inner side of the outer shell. The top, bottom and side of the conical tube thread are all stressed, and the filter device is a sealing structure as a whole. The two-layer liquid medicine filtration structure filters the liquid medicine in sequence and retains the filtered impurities on the side away from the upper connecting tube, which no longer enters the human body with the liquid medicine, thereby filtering the liquid medicine. On the contrary, when the medicine located on the side of the filter membrane close to the upper connecting tube enters the syringe from the direction of the cone head, under the action of atmospheric pressure and the flow force of the medicine, the circular baffle of the one-way valve on the inner shell is embedded and tightly fastened in the matching groove, and the valve of the one-way valve is closed, which can prevent the medicine injected into the syringe from being contaminated.

[0067] Compared with the prior art, the medical built-in filter provided by the present invention filters the liquid medicine in the syringe by arranging a one-way filtering device on the inner shell, and retains the filtered impurities in the syringe, thereby effectively preventing insoluble particles in the medicine from contaminating the liquid medicine and entering the human blood circulation with the liquid medicine, thereby playing a substantial filtering role on the liquid medicine, and has a simple structure, low production cost, and is easy to use. It is suitable for large-scale promotion in medical institutions to ensure the safety of medication and effectively extend the shelf life of drugs.

[0068] The above embodiments are typical examples listed to illustrate the technical solutions of the present invention in detail. The present invention is subject to the protection scope of the claims and the content of the invention and is not limited by the implementation scheme. Simple replacement or modification of the present invention is still within the protection scope of the present invention.

Claims

1. A medical internal filter, characterized in that: It includes an upper connecting pipe, an outer shell and an inner shell which are connected in sequence by elastic sealing and are detachable; The inner shell is provided with a one-way filtering device; A filter membrane is arranged in the cavity formed between the inner shell and the outer shell.

2. The medical internal filter according to claim 1, characterized in that: The portion of the upper connecting pipe extending into the interior of the outer shell forms a bubble retaining ring, and a gas storage cavity is formed between the bubble retaining ring, the outer shell and the filter membrane.

3. The medical internal filter according to claim 1, characterized in that: The one-way filtering device includes a liquid channel and an elastic one-way valve for controlling the flow direction of the liquid channel; preferably, the elastic one-way valve includes a circular baffle and a groove matching the circular baffle, and the cross-sectional radius of the circular baffle is larger than the cross-sectional radius of the liquid channel.

4. The medical internal filter according to claim 1, characterized in that: The upper connecting tube is a T-shaped tube, comprising a coaxial top tube body, a cylindrical tube body and a conical tube body that are sealed and connected in sequence, and the inner diameter of the top tube body is the same as the inner diameter of the cylindrical tube body, and the thickness of the top tube body is greater than the thickness of the cylindrical tube body.

5. The medical internal filter according to claim 4, characterized in that: The top tube body is connected to the cylindrical tube body via a buckle; The cylindrical tube body and the conical tube body are an integral structure, and the inner wall of the conical tube body is smoothly connected to the inner wall of the cylindrical tube body.

6. The medical internal filter according to claim 1, characterized in that: The outer shell includes a circular ring at the top and a side wall at the bottom, and the circular ring is sealed to the side wall; the filter membrane is fixed in the cavity formed by the outer shell and the inner shell; preferably, the filter membrane is fixed in the cavity formed by the outer shell and the inner shell by a U-shaped supporting structure; more preferably, the U-shaped supporting structure is two U-shaped seats with U-shaped hollow cavities, the two ends of the filter membrane are respectively embedded in the two U-shaped hollow cavities, and the U-shaped supporting structure is an elastomer.

7. The medical internal filter according to claim 6, characterized in that: An annular protrusion is provided at the connection between the top circular ring of the outer shell and the side wall; An elastic sealing ring is provided at the connection between the inner shell and the bottom side wall of the outer shell; The annular protrusion cooperates with the elastic sealing ring to fix the filter membrane and the U-shaped supporting structure for fixing the filter membrane in the cavity formed between the outer shell and the inner shell.

8. The medical internal filter according to claim 6, characterized in that: The conical tube body is connected to the circular ring on the top of the outer shell through a threaded structure; preferably, an external thread is provided on the outer wall of the conical tube body, and an internal thread is provided on the inner wall of the top circular ring, and the internal thread cooperates with the external thread to form a thread pair.

9. The medical internal filter according to claim 8, characterized in that: The heights of the external thread and the internal thread are both smaller than the thickness of the conical tube body, and the screwing length of the thread is smaller than the generatrix length of the outer wall of the conical tube body.

10. The medical internal filter according to claim 6, wherein: The inner shell is an elastic body, and the inner shell is sealed and connected to the side wall of the bottom of the outer shell through a snap-fit, and the inner shell is fixed.

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