Cap assembly and syringe having the same

Abstract

The application discloses a cap assembly and a syringe with the same. The cap assembly comprises: a sublimation cap, the inside of the sublimation cap is formed with a moving channel extending in a straight line direction and a limiting fitting part, the moving channel is provided with a gas channel in communication with the outside, and the outer surface of the sublimation cap is formed with a thread for connecting the syringe; a sealing part, the sealing part is movably arranged in the moving channel, the outer surface of the sealing part is provided with spaced-apart first and second limiting parts, the first and second limiting parts are respectively independently matched with the limiting fitting part, after the first limiting part is matched with the limiting fitting part, the sealing part avoids the gas channel to keep the moving channel in communication with the outside atmosphere, and after the second limiting part is matched with the limiting fitting part, the sealing part closes the gas channel. The cap assembly according to the application has two states of being in communication with the outside atmosphere and being closed, so that the freeze-drying and sealing of the medicine are considered, and the cap assembly can be applied to the process of manufacturing freeze-dried medicine.

Description

Technical Field

[0001] This invention relates to the field of syringes, and more particularly to a cap assembly and a syringe having the same. Background Technology

[0002] In the pharmaceutical industry, many injectable drugs cannot be stored stably for long periods in solution form. They are prepared into powders or lumps with extremely low moisture content through vacuum freeze-drying. Sublimation gases are generated during vacuum freeze-drying and must be expelled through a gas channel. However, the resulting drug powder has low moisture content and is porous, with a surface area 100-150 times larger than before, making it highly hygroscopic. Therefore, the gas channel must be sealed after vacuum freeze-drying.

[0003] How to integrate the freeze-drying and sealing processes of drugs into the manufacturing process of syringe components has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of the present invention is to provide a cap assembly that has two states: selectable for opening to the outside atmosphere and closed, thereby balancing the freeze-drying and sealing of drugs, and enabling the cap assembly to be used in the process of manufacturing freeze-dried drugs.

[0005] The syringe cap assembly according to this application includes: a sublimation cap, wherein the interior of the sublimation cap has a moving channel extending in a straight direction and a limiting fitting, the moving channel having a gas passage communicating with the outside, and the outer surface of the sublimation cap having threads for connecting to a syringe; and a sealing member, wherein the outer surface of the sealing member has a spaced-apart first limiting member and second limiting member, the first limiting member and the second limiting member respectively independently cooperating with the limiting fitting member, wherein after the first limiting member cooperates with the limiting fitting member, the sealing member avoids the gas passage to maintain the moving channel communicating with the outside atmosphere, and after the second limiting member cooperates with the limiting fitting member, the sealing member closes the gas passage.

[0006] According to the cap assembly of this application, by setting a moving channel inside the sublimation cap and movably setting the seal in the moving channel, the cap assembly can achieve two states: connecting the cavity storing the drug to the outside atmosphere or sealing it, thereby solving the synchronization problem in the drug and syringe manufacturing process. Drugs that need to be freeze-dried can be directly filled into the syringe without secondary filling and fusion, reducing the problem of drug contamination.

[0007] According to some embodiments of this application, the limiting effect of the first limiting member and the limiting mating member is weaker than the limiting effect of the second limiting member and the limiting mating member, so as to allow the seal to move from the mating position of the first limiting member and the limiting mating member to the mating position of the second limiting member and the limiting mating member.

[0008] According to some embodiments of this application, the top of the sublimation cap is formed with an insertion end communicating with the moving channel, the bottom of the sublimation cap is formed with a mating end adapted to communicate with a syringe, and the limiting mating member is disposed on the side of the gas channel near the insertion end.

[0009] According to some embodiments of this application, the first limiting member is disposed at the bottom of the second limiting member.

[0010] According to some embodiments of this application, the angle between the first limiting member and the stop surface of the limiting mating member relative to the straight line direction is a first included angle, and the angle between the second limiting member and the stop surface of the limiting mating member relative to the straight line direction is a second included angle, wherein the first included angle is smaller than the second included angle.

[0011] According to some embodiments of this application, the first limiting member has a first guide surface and a first limiting surface that are in contact with each other, the first limiting surface being located on top of the first guide surface, and at least a portion of the first limiting surface protruding radially from the first guide surface.

[0012] According to some embodiments of this application, the first limiting surface is constructed as an inclined surface with a diameter that gradually increases in the direction away from the first guide surface.

[0013] According to some embodiments of this application, the second limiting member has a second guide surface and a second limiting surface, the second limiting surface being located at the top of the second guide surface, and the second limiting surface being radially recessed within the second guide surface.

[0014] According to some embodiments of this application, the second limiting surface is constructed as an annular surface with the same radial dimension.

[0015] According to some embodiments of this application, the limiting fitting protrudes from the inner surface of the moving channel and is configured as a positioning boss located inside the moving channel.

[0016] According to some embodiments of this application, the top of the positioning boss is formed with an inclined surface that slopes radially inward toward the moving channel on the side near the mating end.

[0017] According to some embodiments of this application, a locking cavity is formed at the bottom end of the seal.

[0018] According to some embodiments of this application, the outer periphery of the sublimation cap has a protruding limiting frustum formed at the bottom of the gas channel.

[0019] According to some embodiments of this application, at least a portion of the seal is constructed as a flexible element.

[0020] The syringe according to another aspect of this application is briefly described below.

[0021] The syringe assembly according to this application includes: a needle tube with a locking cap having a mating thread formed therein; and a cap assembly that can be alternatively locked to the locking cap by the thread on its outer surface engaging with the mating thread. The cap assembly is constructed as described in any of the above embodiments. Because the syringe assembly according to this application includes the cap assembly described in any of the above embodiments, the syringe can be filled with a liquid medium, freeze-dried to form a powder medium, and then immediately sealed, improving the safety of the syringe and reducing contamination of the drug during transport.

[0022] According to some embodiments of this application, the syringe assembly further includes: a piston disposed within the injection chamber and dividing the injection chamber into a first cavity and a second cavity, the first cavity being adapted to contain a liquid medium or a powder medium, and the second cavity communicating with the second opening.

[0023] According to some embodiments of this application, the first opening of the needle is connected to the injection chamber, and the first opening is formed with a male Luer lock structure known in ISO 80369-7 2021 and a threaded connection to the sublimation cap.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0026] Figure 1 This is a schematic diagram of the structure of the cap assembly according to an embodiment of this application;

[0027] Figure 2 This is a cross-sectional view of a cap assembly according to an embodiment of this application;

[0028] Figure 3 This is a schematic diagram of the structure of the sealing element according to an embodiment of this application;

[0029] Figure 4This is a schematic diagram of the sublimation cap according to an embodiment of this application;

[0030] Figure 5 This is a schematic diagram of the engagement of the cap assembly according to an embodiment of this application;

[0031] Figure 6 This is a schematic diagram of the syringe assembly according to an embodiment of this application;

[0032] Figure 7 This is a schematic diagram of the freeze-drying process according to an embodiment of this application.

[0033] Figure label:

[0034] Helmet assembly 100,

[0035] Seal 110, pressing surface 111, second limiting surface 112, second guide surface 113, transition slope 114, sealing convex ring 115, first limiting surface 116, first guide surface 117, Luer cone sealing structure 118

[0036] Sublimation cap 120, anti-slip ribs 121, gas channel 122, limiting frustum 123, threaded structure 124, positioning boss 125, inner wall 126;

[0037] Syringe assembly 1000;

[0038] Needle 200, piston 300, powder medium 400, liquid medium 500

[0039] 200 syringes:

[0040] 210 male Luer lock, 220 outer wall of needle, 230 inner wall of needle, 240 injection cavity Detailed Implementation

[0041] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0042] The following is for reference. Figures 1-5 A cap assembly 100 according to an embodiment of the present invention is described.

[0043] The cap assembly 100 according to this application includes a seal 110 and a sublimated cap 120. The sublimated cap 120 has a moving channel extending in a straight direction and a limiting fitting inside. The sublimated cap 120 has a gas channel 122 communicating with the moving channel. The inner surface of the moving channel has a limiting fitting. The seal 110 is movably disposed in the moving channel. The outer surface of the seal 110 is provided with a first limiting member and a second limiting member spaced apart. The first limiting member and the second limiting member respectively independently cooperate with the limiting fitting. After the seal 110 moves to the point where the first limiting member cooperates with the limiting fitting, the seal avoids the gas channel 122 to keep the moving channel communicating with the outside atmosphere. After the seal 110 moves to the point where the second limiting member cooperates with the limiting fitting, the seal 110 closes the gas channel 122.

[0044] The top of the seal 110 has a pressing surface 111. During the manufacturing process of the product, the seal 110 moves relative to the moving channel of the sublimation cap 120 by pressing the pressing surface 111.

[0045] The sealing element 110 is provided with a first limiting element and a second limiting element that cooperate with the limiting element. The first limiting element and the second limiting element are set at two different positions, which further improves the positional accuracy of the sealing element 110, corresponding to the state of opening the gas channel 122 and the state of sealing the gas channel 122 respectively, and avoids misalignment of the sealing element 110.

[0046] According to some embodiments of this application, the top of the sublimation cap 120 has an insertion end communicating with the moving channel, and the bottom of the sublimation cap 120 has a mating end suitable for communicating with the syringe. The seal 110 can enter the moving channel from the top of the sublimation cap 120, and the limiting mating member can limit the seal 110 after it enters the moving channel, thereby preventing the seal 110 from falling directly into the position that seals the gas channel 122 from the outside during installation, and ensuring that the seal 110 will not be misaligned during the freeze-drying process of the syringe.

[0047] In some embodiments of this application, the limiting effect of the first limiting member and the limiting mating member is weaker than that of the second limiting member and the limiting mating member, allowing the sealing member 110 to move from the mating position of the first limiting member and the limiting mating member to the mating position of the second limiting member and the limiting mating member. Since the movement channel needs to be kept unobstructed before freeze-drying and sealed immediately after freeze-drying, setting the limiting effect of the first limiting member and the limiting mating member relatively weakly facilitates further movement of the sealing member 110 towards the bottom. Conversely, setting the limiting effect of the second limiting member and the limiting mating member relatively strong achieves a strong limiting effect between the sealing member 110 and the sublimation cap 120, preventing the sealing member 110 from detaching from the sublimation cap 120 and maintaining the sealing effect of the sealing member 110 after being limited by the second limiting member and the limiting mating member. This improves sealing performance, conforms to the process flow for freeze-drying drugs, and enhances the reliability of the freeze-drying process and the completed freeze-drying process.

[0048] In some embodiments of this application, the top of the sublimation cap 120 has an insertion end communicating with the moving channel, and the bottom of the sublimation cap 120 has a mating end suitable for communicating with the syringe. A limiting mating member is disposed on the side of the gas channel near the insertion end. The limiting mating member is positioned closer to the top of the sublimation cap 120 to ensure that during the installation of the seal 110, the seal 110 will contact the first limiting member with the limiting mating member, preventing the sublimation cap 120 from moving further towards the bottom and improving the mating reliability of the sublimation cap 120.

[0049] In some embodiments of this application, the first limiting member is disposed at the bottom of the second limiting member. During the insertion of the sealing member 110, the first limiting member can engage with the limiting mating part before the second limiting member to maintain the communication state of the moving channel and perform freeze-drying operation at this time. After freeze-drying is completed, the sealing member 110 can move further toward the bottom of the sublimation cap 120, thereby engaging the second limiting member with the limiting mating part to achieve sealing.

[0050] In some embodiments of this application, the angle between the first limiting member and the stop surface of the limiting mating member relative to the straight line direction is a first included angle, and the angle between the second limiting member and the stop surface of the limiting mating member relative to the straight line direction is a second included angle, wherein the first included angle is smaller than the second included angle.

[0051] It should be noted that the first or second limiting member engages with the limiting mating member when the seal 110 is in different positions. The engagement uses a mutual abutment mechanism to limit the relative position of the seal 110 and the sublimation cap 120. Since the limiting effect of the first limiting member is relatively small, and further movement is required, the outer peripheral wall of the first limiting member is inclined to control the friction between the first limiting member and the limiting mating member. The limiting effect of the second limiting member is relatively strong; therefore, the inclination angle of the outer peripheral wall of the second limiting member is larger, ensuring that the force between the second limiting member and the limiting mating member is entirely within the direction of movement of the seal 110. This effectively prevents the seal 110 from moving, providing a strong restraining effect and ensuring that the seal 110 remains firmly in the sealing position.

[0052] According to some embodiments of this application, the first limiting member is disposed at the bottom of the second limiting member. The first limiting member and the second limiting member are arranged sequentially in the extending direction of the sealing member 110. When the first limiting member cooperates with the limiting mating member, the sealing member 110 avoids the gas channel 122. Therefore, the first limiting member needs to contact the limiting mating member first. Since the sealing member 110 has a top insertion of the moving channel, the first limiting member is disposed at the bottom of the second limiting member. This ensures that the first limiting member contacts the limiting mating member first during the cooperation between the sealing member 110 and the sublimation cap 120, ensuring that the sealing member 110 is limited after installation, thus maintaining the flow of the gas channel 122.

[0053] According to some embodiments of this application, the first limiting member has a first guide surface 117 and a first limiting surface 116, the first limiting surface 116 being located at the top of the first guide surface 117, and at least a portion of the first limiting surface 116 protruding radially from the first guide surface 117. The first guide surface 117 first contacts the inner wall 126 of the gas passage 122, and the first guide surface 117 can be configured as an inclined surface from bottom to top to prevent the upper cross section from gradually increasing, thereby providing a positioning and guiding effect for the mating process of the seal 110 and the sublimation cap 120.

[0054] The first limiting surface 116 is located on the top of the first guide surface 117. It can contact the limiting mating part after the seal 110 moves into place, thereby restricting the movement of the seal 110 relative to the sublimation cap 120, preventing the seal 110 from blocking the gas channel 122, and ensuring that the drug can be fully utilized during the vacuum freeze-drying process.

[0055] According to some embodiments of this application, the first limiting surface 116 is constructed as an inclined surface with a gradually increasing diameter in the direction away from the first guide surface 117. In the process flow, the first limiting surface 116 first contacts the limiting mating part. After the freeze-drying operation is completed, the gas channel 122 needs to be further sealed. Constructing the first limiting surface 116 as an inclined surface can reduce the resistance during the movement of the sealing part 110 and prevent the sealing part 110 from being worn out, so that the sealing part 110 can move smoothly to the position where the second limiting part mates with the limiting mating part.

[0056] According to some embodiments of this application, the second limiting member has a second guide surface 113 and a second limiting surface 112, the second limiting surface 112 being located at the top of the second guide surface 113 and radially recessed within the second guide surface 113. The second guide surface 113 may be configured as a slope with a decreasing diameter component in the direction toward the top, so as to facilitate the movement of the seal 110 relative to the sublimation cap 120 and prevent interference between the limiting mating member and the seal 110.

[0057] The second limiting surface 112 is recessed within the second guide surface 113, and a groove is formed on the outer periphery of the sealing member 110. A first step for engaging with the limiting mating member can be formed at the top of the second limiting surface 112, and a second step for engaging with the limiting mating member is formed at the bottom of the second limiting surface 112. The limiting mating member is embedded in the groove and abuts against the first step and the second step in two directions respectively, so as to achieve positioning of the sealing member 110.

[0058] According to some embodiments of this application, the second limiting surface 112 is constructed as an annular surface with the same radial dimension. That is, the second limiting surface 112 is the inner wall surface of the groove in the radial direction. The groove is an annular groove provided on the outer periphery of the seal 110. The seal 110 is limited by the first step and the second step respectively.

[0059] According to some embodiments of this application, a sealing protrusion 115 is also provided on the top of the first limiting surface 116. The sealing protrusion 115 is used to stop the airflow through the moving channel and ensure the reliability of the vacuum freeze-drying process.

[0060] According to some embodiments of this application, a transition slope 114 is further provided between the sealing ring 115 and the second guide surface 113. The diameter of the transition slope gradually decreases in the direction toward the second guide surface to reduce friction on the seal 110.

[0061] According to some embodiments of this application, the limiting fitting protrudes from the inner surface of the moving channel and is configured as a positioning boss 125 located inside the moving channel. By setting the limiting fitting to protrude from the inner surface of the moving channel, the limiting fitting can contact the first guide surface 117, the first limiting surface 116, the second guide surface 113, and the second limiting surface 112, and finally be embedded into the groove, thereby restricting the movement of the seal 110 in the position of avoiding the gas channel 122 and the position of closing the gas channel 122, ensuring the stability of the seal 110.

[0062] According to some embodiments of this application, the top of the positioning boss 125 is formed with an inclined surface that slopes radially inward toward the moving channel on the side near the mating end. It can be understood that the top surface of the positioning boss 125 is constructed as an inclined surface, which slopes downward toward the center of the moving channel. This allows the positioning boss 125 to guide the seal 110 when it contacts the first guide surface 117 and the second guide surface 113, ensuring that the seal 110 moves to the center position of the moving channel. Simultaneously, this inclined surface also reduces the difficulty of relative movement after contact with the first guide surface 117, preventing wear on the seal 110.

[0063] According to some embodiments of this application, at least a portion of the seal 110 is constructed as a flexible element to better achieve a seal for the sublimation cap 120. The seal 110 may be made of polyisoprene, brominated butyl rubber, chlorinated butyl rubber, fluororubber, or thermoplastic elastomer, with a hardness range of 20 to 80 HA.

[0064] According to some embodiments of this application, the material of the sublimation cap 120 may be polypropylene, polyethylene, polystyrene, polycarbonate, polymethyl methacrylate, and acrylonitrile-butadiene-styrene copolymer.

[0065] The following is for reference. Figures 6-7 Description of a syringe assembly according to another aspect of this application

[0066] The syringe assembly 1000 according to this application includes: a needle tube 200, wherein an injection chamber 240 is formed within the needle tube, and a first opening and a second opening are respectively formed at both ends of the needle tube 200; the injection chamber 240 is adapted to contain a powder medium 400 or a liquid medium 500; and a cap assembly 100, which is connected to the needle tube 200, and the cap assembly 100 is constructed as described in any of the above embodiments; wherein the cap assembly 100 can selectively connect the injection chamber 240 to the outside atmosphere through a gas channel 122 or close it. Because the syringe assembly 1000 according to this application is provided with the cap assembly 100 described in any of the above embodiments, the syringe can achieve filling with liquid medium 500, freeze-drying the liquid medium 500 to form powder medium 400, and then immediately sealing it, thereby improving the safety of the syringe assembly 1000 and reducing drug contamination during transport.

[0067] According to some embodiments of this application, the syringe assembly 1000 further includes a piston 300 disposed within the injection chamber 240 and dividing the injection chamber 240 into a first cavity and a second cavity, the first cavity communicating with the first opening and adapted to contain a powder medium 400 or a liquid medium 500, and the second cavity communicating with the second opening.

[0068] According to some embodiments of this application, the first opening of the needle 200 is connected to the injection chamber 240, and the first opening is formed with a male Luer lock 210 known in ISO 80369-7 2021 and connected to the threaded structure 124 of the sublimation cap 120.

[0069] According to some embodiments of this application, the outer peripheral wall of the sublimation cap 120 is formed with a thread 124, which extends to the bottom of the gas channel 122. The thread 124 on the outer peripheral wall of the sublimation cap 120 enables a detachable engagement between the cap assembly 100 and the needle tube 200.

[0070] According to some embodiments of this application, a protruding limiting frustum 123 is formed on the outer periphery of the sublimation cap 120 at the bottom of the gas channel 122. The limiting frustum 123 is used to abut against the syringe. The cap assembly 100 and the needle tube 200 are locked together by the threaded structure 124 and the male Luer lock 210.

[0071] According to some embodiments of this application, the cap assembly 100 is disposed on the male Luer lock 210. The cap assembly 100 has a first opening position and a second opening position. In the first opening position, it is connected to the outside of the injection chamber 240, and in the second opening position, it is disconnected from the outside of the injection chamber 240.

[0072] According to some embodiments of this application, the bottom end of the cap assembly 100 has a threaded structure 124, and the bottom end of the seal 110 of the cap assembly has a locking cavity. The inner wall 126 of the locking cavity is constructed as a tapered cavity with a diameter gradually decreasing towards the top, for engaging with the male Luer lock 210 of the syringe 200 to achieve a seal on the syringe tip, thereby improving reliability. The bottom of the seal 110 has a Luer cone sealing structure 118, which can be used to engage with the male Luer lock 210 to achieve a sealed connection.

[0073] The cap assembly 100 of this application enables direct vacuum freeze-drying and sealing when a liquid medium 500 is placed inside the syringe. This realizes the manufacturing process of a syringe carrying a powder medium 400, greatly reducing the manufacturing cost and combining the freeze-drying and sealing processes of the drug.

[0074] During use, just like a traditional cap structure, after unscrewing and removing the cap assembly 100, the needle 200 can be connected to the injection device to perform injection.

[0075] According to some embodiments of this application, the male Luer lock 210 can be an integral structure with the needle tube 200, or it can be a separate structure from the needle tube 200.

[0076] According to some embodiments of this application, the inner wall 230 of the needle may have a partially recessed flow channel feature.

[0077] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this 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 on this invention.

[0078] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0079] In the description of this invention, "a plurality of" means two or more.

[0080] In the description of this invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0081] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0082] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0083] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A cap assembly for a syringe, characterized in that, include: A sublimation cap, wherein the interior of the sublimation cap has a moving channel extending in a straight direction and a limiting fitting, the moving channel is provided with a gas channel communicating with the outside, and the outer surface of the sublimation cap is formed with threads for connecting a syringe. A sealing element is movably disposed within the moving channel. The outer surface of the sealing element is provided with a spaced-apart first limiting member and a second limiting member. The first and second limiting members independently engage with a limiting mating member. When the first limiting member engages with the limiting mating member, the sealing element avoids the gas channel to maintain communication between the moving channel and the external atmosphere. When the second limiting member engages with the limiting mating member, the sealing element closes the gas channel. The limiting effect of the first limiting member and the limiting mating member is weaker than the limiting effect of the second limiting member and the limiting mating member, allowing the sealing element to be positioned by the first limiting member and the limiting mating member. The mating part moves to the position where the second limiting member mates with the limiting mating part; the top of the sublimation cap has an insertion end communicating with the moving channel, and the bottom of the sublimation cap has a mating end suitable for communicating with the syringe; the limiting mating part is disposed on the side of the gas channel near the insertion end; the first limiting member is disposed at the bottom of the second limiting member; the angle between the first limiting member and the stopping surface of the limiting mating part relative to the straight line direction is a first angle, and the angle between the second limiting member and the stopping surface of the limiting mating part relative to the straight line direction is a second angle, and the first angle is smaller than the second angle.

2. The cap assembly for a syringe according to claim 1, characterized in that, The first limiting member has a first guide surface and a first limiting surface that are in contact with each other, the first limiting surface is located on top of the first guide surface, and at least a portion of the first limiting surface protrudes radially from the first guide surface.

3. The cap assembly for a syringe according to claim 2, characterized in that, The first limiting surface is constructed as an inclined surface whose diameter gradually increases in the direction away from the first guide surface.

4. The cap assembly for a syringe according to claim 1, characterized in that, The second limiting member has a second guide surface and a second limiting surface, the second limiting surface being located at the top of the second guide surface, and the second limiting surface being radially recessed into the second guide surface.

5. The cap assembly for a syringe according to claim 4, characterized in that, The second limiting surface is constructed as an annular surface with the same radial dimension.

6. The cap assembly for a syringe according to claim 1, characterized in that, The limiting fitting protrudes from the inner surface of the moving channel and is configured as a positioning boss located inside the moving channel.

7. The cap assembly for a syringe according to claim 6, characterized in that, The top of the positioning boss has a slope that is radially inward toward the moving channel on the side near the mating end.

8. The cap assembly for a syringe according to claim 1, characterized in that, A locking cavity is formed at the bottom end of the seal.

9. The cap assembly for a syringe according to claim 1, characterized in that, The outer periphery of the sublimation cap has a protruding limiting frustum formed at the bottom of the gas channel.

10. The cap assembly for a syringe according to claim 1, characterized in that, At least a portion of the seal is constructed as a flexible element.

11. A syringe assembly, characterized in that, include: A needle tube, wherein the needle tube is provided with a locking cap, and the locking cap has a mating thread; A cap assembly, wherein the cap assembly is alternatively locked to the locking cover by the thread on its outer surface engaging with the mating thread, the cap assembly being constructed as described in any one of claims 1-10.

12. The syringe assembly according to claim 11, characterized in that, The syringe also includes an injection chamber formed within the needle tube. A piston is disposed within the injection chamber and divides the injection chamber into a first chamber and a second chamber, the first chamber being adapted to contain liquid drugs or powder media.

Images