Piston pushrod assembly and self-venting syringe

Abstract

The utility model discloses a piston push rod assembly and self exhaust syringe relates to medical instrument technical field, and this self exhaust syringe includes needle cylinder and float valve, the piston push rod assembly includes push rod body and check valve, push rod body is along up and down direction and is slidably fitted in the inner chamber of needle cylinder, and the portion of the inner chamber of needle cylinder is located below push rod body constitutes the liquid storage chamber, is equipped with air channel in push rod body, and the upper end of air channel is communicated outside, and the lower end of air channel is communicated liquid storage chamber, the lower end part of push rod body is movably connected with float valve, float valve is used for moving upward under the buoyancy of liquid in liquid storage chamber to the plugging of the lower end of air channel, check valve is arranged in air channel, and check valve allows gas to flow from the lower end of air channel to the upper end of air channel, and check valve is used for preventing gas to flow from the upper end of air channel to the lower end of air channel. This scheme can mix the gas in the discharge injection liquid at the same time, avoids injection liquid to be discharged together and causes waste and environmental pollution.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and in particular to a piston push rod assembly and a self-venting syringe. Background Technology

[0002] In medical practice, syringes are commonly used for drug administration, vaccination, blood drawing, and contrast agent injection. Before performing an injection, it is often necessary to manually remove any gas mixed in with the syringe to prevent air bubbles from entering the patient's body with the injection fluid, causing discomfort or even serious complications.

[0003] During manual venting, in order to ensure that the gas inside the syringe is completely expelled, the operator often squeezes out a portion of the injection fluid from the injection port. This results in waste of the injection fluid and makes it unsuitable for occasions where the injection dosage is strictly required. In addition, the expelled injection fluid may also pollute the environment. Utility Model Content

[0004] The main purpose of this invention is to provide a piston pusher assembly designed to be used in conjunction with a syringe to expel gas mixed in the injection solution while avoiding the injection solution being expelled along with the liquid, thus preventing waste and environmental pollution.

[0005] To achieve the above objectives, the piston push rod assembly proposed in this utility model is applied to a self-venting injector, the self-venting injector including a syringe and a float valve; the piston push rod assembly includes:

[0006] The push rod body is slidably fitted into the inner cavity of the syringe in a vertical direction. The portion of the inner cavity of the syringe located below the push rod body forms a liquid storage chamber. The push rod body has an air passage, the upper end of which communicates with the outside, and the lower end of which communicates with the liquid storage chamber. The lower end of the push rod body is movably connected to a float valve. The float valve is used to move upward under the buoyancy of the liquid in the liquid storage chamber to block the lower end of the air passage.

[0007] A one-way valve is disposed in the air passage, the one-way valve allows gas to flow from the lower end of the air passage to the upper end of the air passage, and the one-way valve is used to prevent gas from flowing from the upper end of the air passage to the lower end of the air passage.

[0008] In one embodiment, a first seal is provided between the one-way valve and the cavity wall of the air passage.

[0009] In one embodiment, the lower end of the airway is provided with an annular flange extending radially inward.

[0010] In one embodiment, the lower end face of the annular flange extends downward in a direction away from the central axis.

[0011] In one embodiment, the push rod body has a receiving cavity, the upper part of the receiving cavity is connected to the lower end of the air passage, the lower part of the receiving cavity is connected to the liquid storage cavity, and the cross-sectional area of ​​the receiving cavity is larger than the cross-sectional area of ​​the air passage; the annular flange is disposed on the lower part of the receiving cavity.

[0012] In one embodiment, the piston push rod assembly further includes a second seal, which is fitted onto the outer cylindrical surface of the push rod body. The second seal is used to seal against the inner wall of the syringe, and the height of the second seal is within the height range covered by the receiving cavity.

[0013] In one embodiment, the receiving cavity includes a first chamber and a second chamber. The upper part of the first chamber is connected to the lower end of the airway, the lower part of the first chamber is connected to the upper part of the second chamber, and the lower part of the second chamber is connected to the liquid storage chamber. The annular flange is disposed on the lower part of the second chamber, and the cross-sectional area of ​​the second chamber is larger than that of the first chamber. The one-way valve is snap-fitted into the first chamber.

[0014] In one embodiment, the height of the first chamber is higher than the height of the one-way valve, and there is a first preset distance between the bottom surface of the one-way valve and the second chamber in the vertical direction.

[0015] In one embodiment, a stop structure is provided at the upper opening of the syringe;

[0016] The upper end of the push rod body is provided with a first limiting flange extending radially outward; the upper end of the stop structure is used to abut against the first limiting flange to prevent the push rod body from moving downward relative to the syringe.

[0017] In one embodiment, the middle part of the push rod body is provided with a second limiting flange extending radially outward, and the second limiting flange is slidably fitted in the inner cavity of the syringe in the vertical direction; the lower end of the stop structure is used to abut against the second limiting flange to prevent the push rod body from moving upward relative to the syringe.

[0018] In one embodiment, the piston push rod assembly further includes a second seal, which is fitted onto the outer cylindrical surface of the push rod body and is used to seal against the inner wall of the syringe.

[0019] In one embodiment, the push rod body has at least two air outlets, which are arranged at intervals along the circumference of the push rod body, and the at least two air outlets are connected to the upper end of the air passage.

[0020] In one embodiment, the upper end of the push rod body is provided with a first finger ring.

[0021] This utility model also proposes a self-venting injector, which includes a syringe, a float valve, and a piston rod assembly as described above.

[0022] The push rod body slides vertically within the inner cavity of the syringe, and the portion of the inner cavity of the syringe located below the push rod body forms a liquid storage chamber; the lower end of the air passage communicates with the liquid storage chamber; the lower end of the push rod body is movably connected to the float valve; the float valve is used to move upward under the buoyancy of the injection liquid in the liquid storage chamber to block the lower end of the air passage.

[0023] In the technical solution of this utility model, an air passage is provided inside the push rod body, and a one-way valve is installed in the air passage. The push rod body is slidably fitted in the syringe, and a float valve is installed between the liquid storage chamber of the syringe and the air passage. During the venting process after liquid aspiration, the communication state between the liquid storage chamber and the air passage can be adaptively changed by the movement of the float valve relative to the push rod body. When the float valve is at the first height position relative to the push rod body, the air passage is connected to the liquid storage chamber, and the gas in the liquid storage chamber can be discharged outward through the air passage. After the gas in the liquid storage chamber is emptied, the float valve rises to the second height position relative to the push rod body under the buoyancy of the liquid in the liquid storage chamber. At this time, the float valve forms a sealing effect between the air passage and the liquid storage chamber, which can prevent the liquid in the liquid storage chamber from leaking along the air passage. The one-way valve can prevent external gas from entering the float valve and the liquid storage chamber through the air passage and interfering with the venting operation during the above-mentioned venting process. Based on this solution, the gas mixed in the reservoir can be emptied without adjusting the placement of the self-venting syringe, avoiding the liquid in the reservoir being discharged along with it, and avoiding gas backflow. This reduces the waste of injection solution, is applicable to occasions with strict requirements on injection dosage, and avoids the problem of environmental pollution caused by accidental discharge of injection solution. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0025] Figure 1A three-dimensional structural schematic diagram of an embodiment of the piston push rod assembly provided by this utility model;

[0026] Figure 2 A schematic diagram of the overall front view of an embodiment of the self-venting injector provided by this utility model in its initial state;

[0027] Figure 3 A schematic cross-sectional view of the self-venting injector provided by this utility model in its initial state.

[0028] Figure 4 A schematic diagram of the overall front view of an embodiment of the self-venting injector provided by this utility model when it is in the suction state;

[0029] Figure 5 A schematic cross-sectional view of the self-venting injector provided by this utility model in the suction state in one embodiment;

[0030] Figure 6 A partial cross-sectional structural schematic diagram of the float valve relative to the push rod body at a first height position in one embodiment of the self-venting injector provided by this utility model;

[0031] Figure 7 A schematic diagram of the overall cross-sectional structure of the self-venting injector provided by this utility model when the float valve is at the second height position relative to the push rod body in one embodiment of the self-venting injector;

[0032] Figure 8 This is a partial cross-sectional view of a self-venting injector provided by the present invention, showing the float valve at a second height relative to the push rod body.

[0033] Explanation of icon numbers:

[0034] 1. Syringe; 11. Injection port; 12. Liquid reservoir; 13. Stop structure; 14. Second ring; 15. Third ring;

[0035] 2. Piston push rod assembly; 21. Push rod body; 22. One-way valve; 211. Air passage; 212. Annular flange; 213. Exhaust passage; 214. Receiving cavity; 215. First limiting flange; 216. Second limiting flange; 217. Air outlet; 218. First finger ring; 2141. First chamber; 2142. Second chamber;

[0036] 3. Float valve; 31. Limiting shoulder; 32. Connecting neck; 33. Float section;

[0037] 4. First sealing element;

[0038] 5. Second sealing element.

[0039] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0040] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0041] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0042] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0043] In medical practice, syringes are commonly used for drug administration, vaccination, blood drawing, and contrast agent injection. Before performing an injection, it is often necessary to manually remove any gas mixed in with the syringe to prevent air bubbles from entering the patient's body with the injection fluid, causing discomfort or even serious complications.

[0044] During manual venting, in order to ensure that the gas inside the syringe is completely expelled, the operator often squeezes out a portion of the injection fluid from the injection port. This results in waste of the injection fluid and makes it unsuitable for occasions where the injection dosage is strictly required. In addition, the expelled injection fluid may also pollute the environment.

[0045] To address the aforementioned problems, this invention provides a piston pusher assembly designed for use with a syringe to expel gas mixed in the injection solution while preventing the injection solution from being expelled along with it, thus avoiding waste and environmental pollution.

[0046] Please see Figures 1 to 8 The piston push rod assembly 2 provided by this utility model is applied to a self-venting syringe, which includes a syringe 1 and a float valve 3; the piston push rod assembly 2 includes:

[0047] The push rod body 21 is used to slide in the inner cavity of the syringe 1 in the vertical direction. The part of the inner cavity of the syringe 1 located below the push rod body 21 forms a liquid storage cavity 12. The push rod body 21 is provided with an air passage 211. The upper end of the air passage 211 is connected to the outside, and the lower end of the air passage 211 is connected to the liquid storage cavity 12. The lower end of the push rod body 21 is used to be movably connected to a float valve 3. The float valve 3 is used to move upward under the buoyancy of the liquid in the liquid storage cavity 12 to block the lower end of the air passage 211.

[0048] One-way valve 22 is disposed in air passage 211. One-way valve 22 allows gas to flow from the lower end of air passage 211 to the upper end of air passage 211, and one-way valve 22 is used to prevent gas from flowing from the upper end of air passage 211 to the lower end of air passage 211.

[0049] In this embodiment, the upper end of the push rod body 21 is located outside the syringe 1. The operator can drive the push rod body 21 to move up and down relative to the syringe 1 by holding the upper end of the push rod body 21. The circumferential sidewall of the lower end of the push rod body 21 can be sealed with the inner wall of the syringe 1 in the circumferential direction. The bottom of the syringe 1 is provided with an injection port 11. When the operator drives the push rod body 21 to move upward relative to the syringe 1, the liquid at the injection port 11 can be drawn into the reservoir 12 based on the negative pressure. When the operator drives the push rod body 21 to move downward relative to the syringe 1, the liquid in the reservoir 12 can be discharged outward through the injection port 11 based on the positive pressure, thereby completing the injection operation. The liquid drawn into the reservoir 12 and used for injection includes, but is not limited to, drugs, saline, blood, contrast agents, etc. The injection port 11 can be used to connect puncture devices such as needles, so that the above-mentioned liquid can be injected into the human body after puncturing the skin with puncture devices.

[0050] The float valve 3 can be movably connected to the lower end of the push rod body 21 using structures such as snaps, barbs, and pins, so as to ensure that the float valve 3 has a certain degree of freedom of movement relative to the push rod body 21 in the vertical direction while avoiding complete separation of the float valve 3 from the push rod body 21. The float valve 3 needs to be positioned directly opposite the lower opening of the air passage 211. When the float valve 3 is in a low position (i.e., when the float valve 3 is at the first height position relative to the push rod body 21), there is a certain gap between a part of the float valve 3 and the lower end of the push rod body 21. In other words, the float valve 3 does not block the lower opening of the air passage 211 at this time. At this time, the gas in the liquid storage chamber 12 can enter the air passage 211 through the gap between the float valve 3 and the lower end of the push rod body 21. When the float valve 3 is in a high position (i.e., when the float valve 3 is at the second height position relative to the push rod body 21), the float valve 3 and the lower end of the push rod body 21 are completely attached and block the lower opening of the air passage 211. At this time, neither the gas nor the liquid in the liquid storage chamber 12 can enter the air passage 211.

[0051] It is understandable that the aforementioned first height position can refer to a height range. When the float valve 3 is in different positions within this height range relative to the push rod body 21, there is a gap between a part of the float valve 3 and the lower end of the push rod body 21 that allows gas to pass through, but the specific size of the gap is different.

[0052] Based on the above settings, in actual operation, the self-venting injector is in the following state when no aspiration operation is performed: Figure 2 and Figure 3 In the initial state shown, the operator can first immerse the injection port 11 into the liquid to be injected, and then proceed as follows: Figure 4 and Figure 5 Pulling the push rod body 21 upwards as shown draws liquid through the injection port 11 into the storage chamber 12. The float valve 3 also moves upwards synchronously under the action of the push rod body 21. When the liquid in the storage chamber 12 reaches a preset value, pulling the push rod body 21 upwards stops. At this time, the gas mixed in the liquid, due to its lower density, will float above the liquid in the storage chamber 12 and contact the float valve 3, even with the piston push rod assembly 2 remaining in the same position. Due to the presence of this gas, the float valve 3 has not yet fully contacted the liquid in the storage chamber 12. Under the weight of the float valve 3 itself, as... Figure 6As shown, the float valve 3 is currently in a low position (i.e., at the first height position) relative to the push rod body 21, and the float valve 3 does not block the lower opening of the air passage 211. The operator can then block the injection port 11 to prevent liquid from being discharged from the injection port 11, and then push the push rod body 21 downwards. Under the pressure of the lower end of the push rod body 21, the gas in the liquid storage chamber 12 will be squeezed and enter the air passage 211 through the gap between the float valve 3 and the lower end of the push rod body 21. As the push rod body 21 continues to move downwards... As the pressure is applied downwards, the gas in the storage chamber 12 will continuously enter the air passage 211 and be discharged outwards from the upper end of the air passage 211. During this process, as the gas is continuously discharged, the contact area between the float valve 3 and the liquid in the storage chamber 12 will gradually increase, and the buoyancy force generated by the liquid on the float valve 3 will also gradually increase. Under the action of this gradually increasing buoyancy force, the float valve 3 will overcome its own weight and gradually move upwards relative to the push rod body 21. The gap between the float valve 3 and the lower end of the push rod body 21 will also gradually decrease as the float valve 3 moves upwards. Figure 7 and Figure 8 As shown, when the float valve 3 moves upward relative to the push rod body 21 to the high position (i.e., at the second height position), the gas in the liquid storage chamber 12 has been completely emptied through the air passage 211. At this time, the float valve 3 and the lower end of the push rod body 21 are completely attached and block the lower opening of the air passage 211. The liquid in the liquid storage chamber 12 will not be able to enter the air passage 211. This avoids leakage of some liquid in the liquid storage chamber 12 through the air passage 211 due to excessive downward pressure of the push rod body 21. Based on the above operation, the venting operation can be completed without adjusting the placement of the self-venting syringe and without preventing the liquid in the liquid storage chamber 12 from being discharged. Subsequently, the seal on the injection port 11 can be released, and the liquid in the liquid storage chamber 12 can be pushed out of the injection port 11 by the push rod body 21 for injection operation.

[0053] The check valve 22 is located above the float valve 3. A relatively large chamber can be provided in the air passage 211 for the installation of the check valve 22. The check valve 22 can be a gravity-type check valve 22, a spring-loaded check valve 22, a diaphragm-type check valve 22, etc., and is not limited here. Among them, the gravity-type check valve 22 usually includes a spherical or conical valve core and a valve seat, with the valve core located above the valve seat. When gas enters from below, the air pressure pushes the valve core up, and the gas can flow through the gap between the valve seat and the valve core. When the gas stops flowing or flows in reverse, the valve core falls back under the action of gravity, closing the valve seat and preventing the gas from flowing in reverse. A spring-loaded check valve 22 typically includes a spring, a valve core, and a valve seat. The spring applies a downward elastic force to the valve core, causing it to press firmly against the valve seat and close the valve. When the gas pressure exceeds the spring's elastic force, the valve core is pushed up, allowing gas to pass through. When the gas pressure decreases or reverses, the spring pushes the valve core back onto the valve seat, closing the valve. A diaphragm-type check valve 22 typically includes a flexible diaphragm and a valve seat, with the diaphragm covering the valve seat. When gas enters from one side, the gas pressure deforms the diaphragm, pushing it to the other side of the valve seat, opening the passage for gas to pass through. When the gas stops or reverses flow, the diaphragm returns to its original shape and closes the passage, preventing reverse gas flow.

[0054] By setting a one-way valve 22, the flow direction of the gas can be restricted, preventing external gas from entering the float valve 3 and the liquid storage chamber 12 through the air passage 211, thus disrupting the relationship between the gas pressure and the liquid buoyancy and interfering with the exhaust operation. This ensures that the gas in the liquid storage chamber 12 can be smoothly discharged from bottom to top through the air passage 211.

[0055] Therefore, the piston push rod assembly 2 provided in this embodiment has an air passage 211 inside the push rod body 21, and a one-way valve 22 is provided in the air passage 211. The push rod body 21 is slidably fitted in the syringe 1, and a float valve 3 is provided between the liquid storage chamber 12 of the syringe 1 and the air passage 211. During the venting process after liquid aspiration, the movement of the float valve 3 relative to the push rod body 21 can adaptively change the communication state between the liquid storage chamber 12 and the air passage 211. When the float valve 3 is at the first height position relative to the push rod body 21, the air passage 211 and the liquid storage chamber 12 are connected. The liquid chamber 12 is connected, and the gas in the liquid storage chamber 12 can be discharged to the outside through the air passage 211. After the gas in the liquid storage chamber 12 is emptied, the float valve 3 rises to the second height position relative to the push rod body 21 under the buoyancy of the liquid in the liquid storage chamber 12. At this time, the float valve 3 forms a sealing effect between the air passage 211 and the liquid storage chamber 12, which can prevent the liquid in the liquid storage chamber 12 from leaking along the air passage 211. The one-way valve 22 can prevent external gas from entering the float valve 3 and the liquid storage chamber 12 through the air passage 211 during the above-mentioned venting process, thus preventing interference with the venting operation. Based on the scheme of this embodiment, the gas mixed in the liquid storage chamber 12 can be emptied without adjusting the placement of the self-venting syringe, preventing the liquid in the liquid storage chamber 12 from being discharged together, and preventing gas backflow. This can reduce the waste of injection fluid, is applicable to occasions with strict requirements for injection dosage, and can avoid the problem of environmental pollution caused by accidental discharge of injection fluid.

[0056] In one embodiment, refer to Figures 1 to 8 A first sealing element 4 is provided between the one-way valve 22 and the cavity wall of the air passage 211.

[0057] Specifically, the first sealing element 4 can be a sealing ring, sealing ring, etc.; taking the sealing ring as an example, a sealing ring groove can be provided on the outer wall of the one-way valve 22, and the first sealing element 4 can be snapped into the sealing ring groove. The outer side of the first sealing element 4 fits against the cavity wall of the air passage 211, so as to achieve a sealing fit between the one-way valve 22 and the cavity wall of the air passage 211.

[0058] By setting the first sealing element 4, the sealing between the one-way valve 22 and the air passage 211 can be guaranteed, preventing external gas from entering the float valve 3 and the liquid storage chamber 12 through the gap between the outer wall of the one-way valve 22 and the cavity wall of the air passage 211, thus interfering with the exhaust operation.

[0059] In one embodiment, refer to Figures 1 to 8 The lower end of the air passage 211 is provided with an annular flange 212 extending radially inward.

[0060] In this embodiment, the annular flange 212 provides a basis for the movable connection of the float valve 3 to the push rod body 21, and can cooperate with the float valve 3 to realize the opening and closing of the air passage 211, as follows:

[0061] like Figure 6 and Figure 8 As shown, the float valve 3 may include a limiting shoulder 31, a connecting neck 32, and a float portion 33 connected sequentially from top to bottom. The connecting neck 32 is movably inserted into the inner ring of the annular flange 212. The cross-sectional area of ​​the connecting neck 32 is smaller than the cross-sectional area of ​​the inner ring of the annular flange 212. The cross-sectional areas of the limiting shoulder 31 and the float portion 33 are both larger than the cross-sectional area of ​​the inner ring of the annular flange 212. The length of the connecting neck 32 in the vertical direction is greater than the length of the annular flange 212 in the vertical direction. The thickness in the downward direction allows the connecting neck 32 to have a certain margin of movement relative to the annular flange 212 in both the radial direction (i.e., the horizontal direction under the illustrated angle) and the axial direction (i.e., the vertical direction under the illustrated angle); the lower side of the limiting shoulder 31 is used to abut against the upper end face of the annular flange 212 to form a limiting effect, ensuring that the push rod body 21 can drive the float valve 3 to move upward through the annular flange 212 while preventing the float valve 3 from detaching from the push rod body 21.

[0062] When the float valve 3 is at the first height position relative to the push rod body 21, such as Figure 5 and Figure 6 As shown, the lower side of the limiting shoulder 31 does not abut against the upper end face of the annular flange 212, and the upper side of the float portion 33 does not fit against the lower end face of the annular flange 212. At this time, a first gap L1 is formed between the limiting shoulder 31 and the upper end face of the annular flange 212, a second gap L2 is formed between the periphery of the connecting neck 32 and the inner ring of the annular flange 212, and a third gap L3 is formed between the float portion 33 and the lower end face of the annular flange 212. The interconnected first gap L1, second gap L2, and third gap L3 together constitute an exhaust channel 213. The upper end of the exhaust channel 213 is connected to the air passage 211, and the lower end of the exhaust channel 213 is connected to the liquid storage chamber 12. At this time, the gas in the liquid storage chamber 12 can enter the air passage 211 through the exhaust channel 213 and be discharged outward.

[0063] As the float valve 3 gradually rises relative to the push rod body 21 under the buoyancy of the liquid in the storage chamber 12, the third gap L3 between the float part 33 and the lower end face of the annular flange 212 gradually decreases; when the float valve 3 reaches the second height position relative to the push rod body 21, such as Figure 7 and Figure 8 As shown, the upper side of the float portion 33 is in contact with the lower end face of the annular flange 212. At this time, the exhaust channel 213 will be blocked, which can prevent the liquid in the liquid storage chamber 12 from entering the air passage 211 through the exhaust channel 213.

[0064] In one embodiment, refer to Figures 1 to 8 The lower end face of the annular flange 212 extends downward in a direction away from the central axis X.

[0065] In this embodiment, the main body of the push rod body 21 can be configured as a rotating body; the aforementioned central axis X can specifically refer to the rotation center axis of the rotating body part, or it can generally refer to the vertical axis located at the center of the push rod body 21. In subsequent embodiments, if the central axis X is mentioned, it can be understood in the same way, and will not be described again.

[0066] The lower end face of the annular flange 212 extends in a direction that has both a radial component (i.e., a horizontal component at the angle shown in the figure) and an axial component (i.e., a vertical component at the angle shown in the figure). The lower end face of the annular flange 212 gradually rises in a radially inward direction (i.e., towards the central axis X). Based on this configuration, at the end of the venting operation, the float valve 3 rises to the second height position relative to the push rod body 21, and the upper side of the float portion 33 fits against the lower end face of the annular flange 212 to form a sealing effect, such as... Figure 8 As shown, at this time, the pressing force F generated by the upper side of the float part 33 against the lower end face of the annular flange 212 has a first vertical upward component F1 and a second horizontal component F2. The second component F2 can push the corresponding part on the periphery of the push rod body 21 to press against the inner wall of the syringe 1 radially outward. In this way, the abutting action between the float valve 3 and the push rod body 21 can be used to improve the sealing effect between the push rod body 21 and the syringe 1, and can better prevent the liquid in the liquid storage chamber 12 from leaking outward through the gap between the push rod body 21 and the syringe 1.

[0067] Preferably, refer to Figures 1 to 8 The upper surface of the float portion 33 extends downward in a direction away from the central axis X. This allows the shape of the upper surface of the float portion 33 to match the shape of the lower end face of the annular flange 212, ensuring a tight fit between the upper surface of the float portion 33 and the lower end face of the annular flange 212. The lower end face of the annular flange 212 and the upper surface of the float portion 33 can be inclined in a straight line to form a planar structure; alternatively, the lower end face of the annular flange 212 and the upper surface of the float portion 33 can extend in an arc direction to form a more curved structure. Figure 6 and Figure 8 The surface structure shown is not limited here.

[0068] Preferably, refer to Figures 1 to 8The lower end face of the annular flange 212 extends along an arc direction, so that the lower end face of the annular flange 212 forms a curved surface structure. The curved surface structure has high adaptability and can ensure the contact area between the lower end face of the annular flange 212 and the upper side of the float part 33. It can minimize the problem of insufficient contact between the upper side of the float part 33 and the lower end face of the annular flange 212 due to dimensional deviations, thereby ensuring the tightness of the fit and the sealing effect between the float valve 3 and the annular flange 212.

[0069] In one embodiment, refer to Figures 1 to 8 The push rod body 21 has a receiving cavity 214. The upper part of the receiving cavity 214 is connected to the lower end of the air passage 211, and the lower part of the receiving cavity 214 is connected to the liquid storage cavity 12. The cross-sectional area of ​​the receiving cavity 214 is larger than the cross-sectional area of ​​the air passage 211. The annular flange 212 is provided on the lower part of the receiving cavity 214.

[0070] By providing a receiving cavity 214 inside the push rod body 21, on the one hand, it can provide a receiving space for the limiting shoulder 31 of the float valve 3, and on the other hand, it can reduce the wall thickness of the corresponding position of the push rod body 21 based on the larger cross-sectional area of ​​the receiving cavity 214. This makes it easier for the thinner wall position on the push rod body 21 opposite to the receiving cavity 214 to deform radially outward under the compressive force F applied by the float valve 3 (specifically the second component F2 of the compressive force F) and squeeze the inner wall of the syringe 1. This results in a better sealing effect between the outer wall of the push rod body 21 and the inner wall of the syringe 1.

[0071] In one embodiment, refer to Figures 1 to 8 The piston push rod assembly 2 also includes a second seal 5, which is fitted onto the outer cylindrical surface of the push rod body 21. The second seal 5 is used to seal against the inner wall of the syringe 1, and the height of the second seal 5 is within the height range covered by the receiving cavity 214.

[0072] Specifically, the second sealing element 5 can be a sealing ring, sealing ring, etc. Taking the sealing ring as an example, a sealing ring groove can be provided on the outer cylindrical surface of the push rod body 21, and the second sealing element 5 can be snapped into the sealing ring groove. The outer side of the second sealing element 5 is in contact with the inner wall of the syringe 1. The dimensions of the second sealing element 5 and the sealing ring groove can be set according to the dynamic sealing standard. In this way, while ensuring that the push rod body 21 can slide relative to the syringe 1, a sealing fit can be achieved between the outer cylindrical surface of the push rod body 21 and the inner wall of the syringe 1, so as to prevent the liquid in the liquid storage chamber 12 from leaking outward through the gap between the outer cylindrical surface of the push rod body 21 and the inner wall of the syringe 1. At the same time, it can prevent external gas from entering the liquid storage chamber 12 through the gap between the outer cylindrical surface of the push rod body 21 and the inner wall of the syringe 1.

[0073] Preferably, the second sealing element 5 can be configured as multiple and arranged at intervals along the axial direction (i.e., the vertical direction shown in the figure) of the push rod body 21. While improving the sealing effect, it can form at least two fulcrums between the outer cylindrical surface of the push rod body 21 and the inner wall of the syringe 1, so that the push rod body 21 can move stably up and down in the inner cavity of the syringe 1, and avoid the push rod body 21 from deflecting relative to the syringe 1 during the movement.

[0074] When the height of the second seal 5 is within the height range covered by the receiving cavity 214 (i.e., the highest point of the second seal 5 is not higher than the highest point of the receiving cavity 214, and the lowest point of the second seal 5 is not lower than the lowest point of the receiving cavity 214), referring to the previous embodiment, when the target position on the push rod body 21 with a thinner wall thickness opposite to the receiving cavity 214 deforms radially outward under the pressure applied by the float valve 3, it can directly drive the second seal 5 located at the target position to squeeze the inner wall of the syringe 1 outward, thereby improving the tightness of the fit between the second seal 5 and the outer cylindrical surface of the push rod body 21 and the inner wall of the syringe 1. This can improve the sealing effect between the outer wall of the push rod body 21 and the inner wall of the syringe 1, while better avoiding the reduction of the smoothness of the push rod body 21 sliding up and down relative to the syringe 1 due to the direct contact between the rigid part of the push rod body 21 and the inner wall of the syringe 1.

[0075] In one embodiment, refer to Figures 1 to 8 The receiving cavity 214 includes a first chamber 2141 and a second chamber 2142. The upper part of the first chamber 2141 is connected to the lower end of the airway 211, the lower part of the first chamber 2141 is connected to the upper part of the second chamber 2142, and the lower part of the second chamber 2142 is connected to the liquid storage chamber 12. An annular flange 212 is disposed on the lower part of the second chamber 2142. The cross-sectional area of ​​the second chamber 2142 is larger than the cross-sectional area of ​​the first chamber 2141. A one-way valve 22 is snapped into the first chamber 2141.

[0076] By setting the receiving cavity 214 as a stepped first chamber 2141 and second chamber 2142, it can meet the snap-fit ​​installation requirements of the small-sized one-way valve 22. On the other hand, by setting the cross-sectional area of ​​the second chamber 2142 to be larger and minimizing the wall thickness of the target position on the push rod body 21 opposite to the second chamber 2142, it is more conducive to the radial outward deformation of the target position under the compressive force applied by the float valve 3, so as to improve the sealing effect between the push rod body 21 and the syringe 1 by squeezing the inner wall of the syringe 1 through the target position.

[0077] The outer wall of the one-way valve 22 and the wall of the second chamber 2142 can be sealed by the first sealing element 4 to prevent external gas from entering the float valve 3 and the liquid storage chamber 12 through the gap between the outer wall of the one-way valve 22 and the wall of the second chamber 2142, thus interfering with the exhaust operation.

[0078] Furthermore, when the second sealing element 5 of the above embodiment is sleeved on the outer cylindrical surface of the push rod body 21, the height of the second sealing element 5 is within the height range covered by the second chamber 2142. Since the target position on the push rod body 21 opposite to the second chamber 2142 has a thinner wall thickness and is more easily deformed under the compressive force applied by the float valve 3, the second sealing element 5 set at the target position is more likely to squeeze the inner wall of the syringe 1 radially outward under the action of its deformation, thereby further improving the sealing effect between the outer wall of the push rod body 21 and the inner wall of the syringe 1.

[0079] In one embodiment, refer to Figures 1 to 8 The height of the first chamber 2141 is higher than the height of the one-way valve 22, and there is a first preset distance H1 between the bottom surface of the one-way valve 22 and the second chamber 2142 in the vertical direction.

[0080] like Figure 6 As shown, by setting the first preset distance H1, a buffer space can be formed below the one-way valve 22. Even if the float valve 3 touches the top surface of the second chamber 2142 (that is, the interface between the first chamber 2141 and the second chamber 2142) during the rising process, the float valve 3 cannot directly contact the one-way valve 22, thereby avoiding damage to related devices caused by the collision between the float valve 3 and the one-way valve 22.

[0081] In one embodiment, refer to Figures 1 to 8 The upper opening of the syringe 1 is provided with a stop structure 13;

[0082] The upper end of the push rod body 21 is provided with a first limiting flange 215 extending radially outward; the upper end of the stop structure 13 is used to abut against the first limiting flange 215 to prevent the push rod body 21 from moving downward relative to the syringe 1.

[0083] In one embodiment, refer to Figures 1 to 8 The push rod body 21 has a second limiting flange 216 extending radially outward in the middle part, and the second limiting flange 216 slides in the inner cavity of the syringe 1 in the vertical direction; the lower end of the stop structure 13 is used to abut against the second limiting flange 216 to prevent the push rod body 21 from moving upward relative to the syringe 1.

[0084] Illustrationly, the stop structure 13 can be configured as a flange structure detachably connected to the upper opening of the syringe 1 via a snap-fit ​​connection, threaded connection, pin connection, etc.; the first limiting flange 215 and the second limiting flange 216 on the push rod body 21 respectively form a ring-shaped structure. Through the abutting cooperation between the stop structure 13 and the first limiting flange 215 and the second limiting flange 216, the sliding of the push rod body 21 in the inner cavity of the syringe 1 can be limited, which can prevent the push rod body 21 from being pulled out of the syringe 1 due to excessive upward pulling by the operator during the liquid aspiration process, and at the same time, it can prevent the float valve 3 from colliding with the bottom of the inner cavity of the syringe 1 due to excessive downward pressure by the operator during the exhaust and injection processes.

[0085] In addition, the second limiting flange 216 can cooperate with the second sealing member 5 below to limit the push rod body 21 in the radial direction, so as to prevent the push rod body 21 from shaking excessively relative to the syringe 1.

[0086] In one embodiment, refer to Figures 1 to 8 The push rod body 21 has at least two air outlets 217, which are arranged at intervals along the circumference of the push rod body 21, and are connected to the upper end of the air passage 211.

[0087] By setting at least two air outlets 217, it can be ensured that the gas in the air passage 211 can be discharged evenly and smoothly from multiple directions, avoiding the obstruction of gas flow at the upper end of the air passage 211 from affecting the normal operation of the exhaust.

[0088] In one embodiment, refer to Figures 1 to 8 The upper end of the push rod body 21 is provided with a first finger ring 218.

[0089] By setting the first finger ring 218, the operator can better apply force to the push rod body 21. In practical applications, the operator can insert their finger into the first finger ring 218 and move the first finger ring 218 up and down, thereby conveniently driving the push rod body 21 to move up and down relative to the syringe 1, so as to conveniently complete the liquid aspiration, degassing and injection operations.

[0090] The first ring 218 may be disposed on the upper end face of the first limiting flange 215. In some embodiments, the upper part of the first ring 218 may be provided with a horizontally extending transverse stiffener, and the suspended positions at both ends of the transverse stiffener may be connected to the left and right sides of the first ring 218 by two vertical stiffeners respectively, thereby enhancing the structural strength of the first ring 218.

[0091] Preferably, refer to Figures 1 to 8The syringe 1 is equipped with a second finger ring 14 and a third finger ring 15, which are arranged at intervals along the circumference of the syringe 1. In actual operation, the operator can insert the index and middle fingers into the second finger ring 14 and the third finger ring 15 respectively, and insert the thumb into the first finger ring 218. This makes it easier and more convenient to drive the push rod body 21 to move up and down relative to the syringe 1, thus solving the problem of poor grip of the push rod body 21 and making it more in line with the human body's force application characteristics.

[0092] This utility model embodiment also provides a self-venting injector; please refer to [link / reference]. Figures 1 to 8 The self-venting injector includes a syringe 1, a float valve 3, and a piston rod assembly 2 as described in any of the above embodiments;

[0093] The push rod body 21 slides in the inner cavity of the syringe 1 in the vertical direction. The part of the inner cavity of the syringe 1 located below the push rod body 21 forms a liquid storage chamber 12. The lower end of the air passage 211 is connected to the liquid storage chamber 12. The lower end of the push rod body 21 is movably connected to the float valve 3. The float valve 3 is used to move upward under the buoyancy of the injection liquid in the liquid storage chamber 12 to block the lower end of the air passage 211.

[0094] In this embodiment, the upper end of the push rod body 21 is located outside the syringe 1. The operator can drive the push rod body 21 to move up and down relative to the syringe 1 by holding the upper end of the push rod body 21. The circumferential sidewall of the lower end of the push rod body 21 can be sealed with the inner wall of the syringe 1 in the circumferential direction. The bottom of the syringe 1 is provided with an injection port 11. When the operator drives the push rod body 21 to move upward relative to the syringe 1, the injection fluid at the injection port 11 can be drawn into the reservoir 12 based on the negative pressure. When the operator drives the push rod body 21 to move downward relative to the syringe 1, the injection fluid in the reservoir 12 can be discharged outward through the injection port 11 based on the positive pressure, thereby completing the injection operation. The injection fluid drawn into the reservoir 12 and used for injection includes, but is not limited to, drugs, saline, blood, contrast agents, etc. The injection port 11 can be used to connect puncture devices such as needles, so that the injection fluid can be injected into the human body after puncturing the skin with the puncture device.

[0095] The float valve 3 can be movably connected to the lower end of the push rod body 21 using structures such as snaps, barbs, and pins, so as to ensure that the float valve 3 has a certain degree of freedom of movement relative to the push rod body 21 in the vertical direction while avoiding complete separation of the float valve 3 from the push rod body 21. The float valve 3 needs to be positioned directly opposite the lower opening of the air passage 211. When the float valve 3 is in a low position (i.e., when the float valve 3 is at the first height position relative to the push rod body 21), there is a certain gap between a part of the float valve 3 and the lower end of the push rod body 21. In other words, the float valve 3 does not block the lower opening of the air passage 211 at this time. At this time, the gas in the liquid storage chamber 12 can enter the air passage 211 through the gap between the float valve 3 and the lower end of the push rod body 21. When the float valve 3 is in a high position (i.e., when the float valve 3 is at the second height position relative to the push rod body 21), the float valve 3 and the lower end of the push rod body 21 are completely attached and block the lower opening of the air passage 211. At this time, neither the gas nor the injection liquid in the liquid storage chamber 12 can enter the air passage 211.

[0096] It is understandable that the aforementioned first height position can refer to a height range. When the float valve 3 is in different positions within this height range relative to the push rod body 21, there is a gap between a part of the float valve 3 and the lower end of the push rod body 21 that allows gas to pass through, but the specific size of the gap is different.

[0097] Based on the above settings, in actual operation, the self-venting injector is in the following state when no aspiration operation is performed: Figure 2 and Figure 3 In the initial state shown, the operator can first immerse the injection port 11 into the injection solution to be injected, and then proceed as follows: Figure 4 and Figure 5 Pulling the push rod body 21 upwards as shown draws the injection fluid through the injection port 11 into the reservoir 12. The float valve 3 also moves upwards synchronously under the action of the push rod body 21. When the injection fluid in the reservoir 12 reaches a preset value, pulling the push rod body 21 upwards stops. At this time, the gas mixed in with the injection fluid, due to its lower density, will float above the injection fluid in the reservoir 12 and contact the float valve 3, even with the piston push rod assembly 2 remaining in the same position. Due to the presence of this gas, the float valve 3 has not yet fully contacted the injection fluid in the reservoir 12. Under the weight of the float valve 3 itself, as... Figure 6As shown, the float valve 3 is currently in a low position (i.e., at the first height position) relative to the push rod body 21, and the float valve 3 does not block the lower opening of the air passage 211. The operator can then block the injection port 11 to prevent the injection fluid from being discharged from the injection port 11, and then push the push rod body 21 downwards. Under the pressure of the lower end of the push rod body 21, the gas in the reservoir 12 will be squeezed and enter the air passage 211 through the gap between the float valve 3 and the lower end of the push rod body 21. As the push rod body 21 continues to move downwards... Under pressure, the gas in the reservoir 12 will continuously enter the air passage 211 and be discharged outward from the upper end of the air passage 211. During this process, as the gas is continuously discharged, the contact area between the float valve 3 and the injection liquid in the reservoir 12 will gradually increase, and the buoyancy generated by the injection liquid on the float valve 3 will also gradually increase. Under the action of this gradually increasing buoyancy, the float valve 3 will overcome its own weight and gradually move upward relative to the push rod body 21. The gap between the float valve 3 and the lower end of the push rod body 21 will also gradually decrease as the float valve 3 moves upward. Figure 7 and Figure 8 As shown, when the float valve 3 moves upward relative to the push rod body 21 to the high position (i.e., at the second height position), the gas in the reservoir 12 has been completely vented through the air passage 211. At this time, the float valve 3 and the lower end of the push rod body 21 are completely attached and block the lower opening of the air passage 211. The injection liquid in the reservoir 12 will not be able to enter the air passage 211. This avoids leakage of some of the injection liquid in the reservoir 12 through the air passage 211 due to excessive downward pressure of the push rod body 21. Based on the above operation, the venting operation can be completed without adjusting the placement of the self-venting syringe and without preventing the injection liquid in the reservoir 12 from being vented. Subsequently, the seal on the injection port 11 can be released, and the injection liquid in the reservoir 12 can be pushed out of the injection port 11 by the push rod body 21 to perform the injection operation.

[0098] Therefore, the self-venting syringe provided in this embodiment has an air passage 211 inside the plunger body 21, and a one-way valve 22 is provided in the air passage 211. The plunger body 21 is slidably fitted in the syringe 1, and a float valve 3 is provided between the liquid storage chamber 12 of the syringe 1 and the air passage 211. During the venting process after liquid aspiration, the communication state between the liquid storage chamber 12 and the air passage 211 can be adaptively changed by the movement of the float valve 3 relative to the plunger body 21. When the float valve 3 is at the first height position relative to the plunger body 21, the air passage 211 and the liquid storage chamber... The gas in the reservoir 12 can be discharged outward through the air passage 211. After the gas in the reservoir 12 is emptied, the float valve 3 rises to the second height position relative to the push rod body 21 under the buoyancy of the injection liquid in the reservoir 12. At this time, the float valve 3 forms a sealing effect between the air passage 211 and the reservoir 12, which can prevent the injection liquid in the reservoir 12 from leaking along the air passage 211. The one-way valve 22 can prevent external gas from entering the float valve 3 and the reservoir 12 through the air passage 211 during the above-mentioned venting process, thus avoiding interference with the venting operation. Based on the scheme of this embodiment, the gas mixed in the reservoir 12 can be vented without adjusting the placement of the self-venting syringe, avoiding the injection liquid in the reservoir 12 being discharged together, and avoiding gas backflow. This can reduce the waste of injection liquid, is applicable to occasions with strict requirements on injection dosage, and avoids the problem of environmental pollution caused by accidental discharge of injection liquid.

[0099] The specific structure of the piston push rod assembly 2 can be referred to the above embodiments. Since this self-venting injector adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated further here.

[0100] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A piston push rod assembly, characterized in that, Applied to a self-venting injector, the self-venting injector includes a syringe and a float valve; the piston rod assembly includes: The push rod body is slidably fitted into the inner cavity of the syringe in a vertical direction. The portion of the inner cavity of the syringe located below the push rod body forms a liquid storage chamber. The push rod body has an air passage, the upper end of which communicates with the outside, and the lower end of which communicates with the liquid storage chamber. The lower end of the push rod body is movably connected to a float valve. The float valve is used to move upward under the buoyancy of the liquid in the liquid storage chamber to block the lower end of the air passage. A one-way valve is disposed in the air passage, the one-way valve allows gas to flow from the lower end of the air passage to the upper end of the air passage, and the one-way valve is used to prevent gas from flowing from the upper end of the air passage to the lower end of the air passage.

2. The piston push rod assembly as claimed in claim 1, characterized in that, A first sealing element is provided between the one-way valve and the cavity wall of the air passage; And / or, the lower end of the airway is provided with an annular flange extending radially inward.

3. The piston push rod assembly as described in claim 2, characterized in that, The lower end face of the annular flange extends downward in a direction away from the central axis.

4. The piston push rod assembly as described in claim 2, characterized in that, The push rod body has a receiving cavity, the upper part of which is connected to the lower end of the air passage, and the lower part of which is connected to the liquid storage cavity. The cross-sectional area of ​​the receiving cavity is larger than the cross-sectional area of ​​the air passage. The annular flange is provided on the lower part of the receiving cavity.

5. The piston push rod assembly as claimed in claim 4, characterized in that, The piston push rod assembly further includes a second seal, which is fitted onto the outer cylindrical surface of the push rod body. The second seal is used to seal against the inner wall of the syringe, and the height of the second seal is within the height range covered by the receiving cavity.

6. The piston push rod assembly as claimed in claim 4, characterized in that, The receiving cavity includes a first chamber and a second chamber. The upper part of the first chamber is connected to the lower end of the airway, the lower part of the first chamber is connected to the upper part of the second chamber, and the lower part of the second chamber is connected to the liquid storage chamber. The annular flange is disposed on the lower part of the second chamber, and the cross-sectional area of ​​the second chamber is larger than that of the first chamber. The one-way valve is snap-fitted into the first chamber.

7. The piston push rod assembly as claimed in claim 6, characterized in that, The height of the first chamber is higher than the height of the one-way valve, and there is a first preset distance between the bottom surface of the one-way valve and the second chamber in the vertical direction.

8. The piston push rod assembly as claimed in claim 1, characterized in that, The upper opening of the syringe is provided with a stop structure; The upper end of the push rod body is provided with a first limiting flange extending radially outward; the upper end of the stop structure is used to abut against the first limiting flange to prevent the push rod body from moving downward relative to the syringe. And / or, the middle part of the push rod body is provided with a second limiting flange extending radially outward, and the second limiting flange slides in the inner cavity of the syringe in the vertical direction; the lower end of the stop structure is used to abut against the second limiting flange to prevent the push rod body from moving upward relative to the syringe.

9. The piston push rod assembly as claimed in claim 1, characterized in that, The piston push rod assembly further includes a second seal, which is fitted onto the outer cylindrical surface of the push rod body and is used to seal against the inner wall of the syringe. And / or, the push rod body is provided with at least two air outlets, the at least two air outlets are arranged at intervals along the circumference of the push rod body, and the at least two air outlets are connected to the upper end of the air passage; And / or, the upper end of the push rod body is provided with a first finger ring.

10. A self-venting injector, characterized in that, The self-venting injector includes a syringe, a float valve, and a piston rod assembly as described in any one of claims 1 to 9; The push rod body slides vertically within the inner cavity of the syringe, and the portion of the inner cavity of the syringe located below the push rod body forms a liquid storage chamber; the lower end of the air passage communicates with the liquid storage chamber; the lower end of the push rod body is movably connected to the float valve; the float valve is used to move upward under the buoyancy of the injection liquid in the liquid storage chamber to block the lower end of the air passage.

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