Hand wound surface negative pressure drainage device

Abstract

The invention discloses a hand wound surface negative pressure drainage device, and relates to the technical field of medical instruments, the hand wound surface negative pressure drainage device comprises a negative pressure drainage device main body and an injector, the injector comprises an injection tube and a piston hermetically and slidably connected in the injection tube, and one end of the piston is connected with a piston rod; the piston comprises a piston ring, the outer ring wall of the piston ring is in sealed sliding connection with the pipe wall of the injection pipe, and at least one convex ring concentric with the piston ring is arranged on the inner ring wall of the piston ring; according to the invention, the convex ring separates the left piston plate and the right piston plate, when the piston rod is pushed to move leftwards, the right piston plate abuts against the convex ring and drives the whole piston ring to move leftwards, and at the moment, a gap is formed between the left piston plate and the convex ring and serves as a gas leakage channel to discharge gas from an outlet in the right end of the injector; the left piston plate pushes the convex ring to drive the piston ring to move rightwards, the gap is closed to enable the piston ring to recover the sealing state, and therefore repeated pipeline air exhaust can be achieved, and long-time attraction force is maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a negative pressure drainage device for hand wounds. Background Art

[0002] In specialties such as plastic surgery, burn department, and orthopaedics for trauma, there is a great demand for using negative pressure suction to treat wounds. Negative pressure suction can timely drain the exudate from the wound surface, create a negative pressure environment to reduce the growth of bacteria, and the negative pressure environment is beneficial to the growth of granulation tissue and wound repair.

[0003] When using a wound surface negative pressure drainage device, it is necessary to first trim the medical foam according to the shape of the wound surface to ensure that it tightly fills the concave part of the wound surface. Then, bury the side hole of the drainage tube in the center of the foam and fix it with absorbable thread or medical glue. Next, connect the other end of the drainage tube to the collection bottle, and finally connect the negative pressure device. The commonly used portable negative pressure devices are syringes or balloons. The syringe generates negative pressure by pulling the piston, and the balloon relies on being flattened and then released to form negative pressure. The materials such as syringes and balloons have extremely low costs and belong to conventional medical consumables, which are very popular in resource-poor areas or for temporary treatment, avoiding delays in treatment due to equipment shortages.

[0004] However, the negative pressure duration of such portable negative pressure devices is extremely short, and repeated operations are required to maintain the attraction. When the piston of the syringe rebounds or the balloon resumes its shape, if the piston is directly pushed back or the balloon is squeezed, the gas will be pushed back in the reverse direction, causing the wound exudate that has been aspirated into the pipeline to flow back to the wound.

[0005] To avoid this problem, it is necessary to disconnect the connection between the negative pressure device and the pipeline before each re-pressurization, but this operation will significantly increase the complexity of the steps. Moreover, frequent plugging and unplugging not only prolongs the treatment time but also reduces the sealing performance due to repeated wear of the interface, and even causes air leakage or liquid leakage. Summary of the Invention

[0006] The purpose of the present invention is to provide a negative pressure drainage device for hand wounds to solve the problems raised in the above background art.

[0007] To solve the above technical problems, a negative pressure drainage device for hand wounds provided by the present invention includes a negative pressure drainage device main body and a syringe. The syringe includes an injection tube and a piston that is hermetically and slidably connected to the injection tube. One end of the piston is connected to a piston rod. The piston includes

[0008] a piston ring. The outer wall of the piston ring is hermetically and slidably connected to the inner wall of the injection tube. At least one convex ring concentric with the piston ring is provided on the inner wall of the piston ring, and the convex ring extends towards the center of the piston ring.

[0009] Two piston plates are spaced apart on the piston rod. The orthographic projections of the two piston plates along the axial direction of the injection tube at least cover the annular opening area of the convex ring. At least one air release opening is provided on the piston plate close to the piston rod for the piston tube to communicate with the outside when the piston rod is pushed.

[0010] Furthermore, at least two convex rings concentric with the piston ring are spaced apart on the inner ring wall of the piston ring. The two convex rings extend towards the center of the piston ring to form a limiting groove, and the piston plate on the side close to the piston rod is located in the limiting groove.

[0011] Furthermore, the two piston plates include a first piston plate and a second piston plate. The second piston plate is located in the limiting groove. The center of the first piston plate bulges towards the interface end of the syringe, forming a convex first piston plate.

[0012] Furthermore, an elastic plate is arranged on the periphery of the first piston plate. The elastic plate is elastic. One end of the elastic plate is connected to the outer ring wall of the first piston plate, and the other end extends towards the convex ring and forms an included angle with the outer ring wall of the first piston plate. There is a gap between the outer ring wall of the elastic plate and the outer ring wall of the convex ring;

[0013] A snap ring is further included, which is arranged on one side of the included angle. One end of the snap ring is connected to the outer wall of the convex ring, and the other end corresponds to the included angle. The inner ring walls of the snap ring are arranged in parallel, and there is a height difference at both ends of the outer ring wall of the snap ring, forming a convex surface.

[0014] Furthermore, a sealing ring is installed on the outer ring wall of the elastic plate. There is a gap between the outer ring surface of the sealing ring and the outer ring wall of the convex ring.

[0015] Furthermore, a flange is installed at one end of the piston ring corresponding to the syringe interface. The sealing ring and the snap ring are both located within the area surrounded by the flange, and there are gaps between the outer ring surfaces of the sealing ring and the snap ring and the inner ring wall of the flange.

[0016] Furthermore, there are multiple air release openings. The air release openings are opened on the second piston plate. The multiple air release openings extend equidistantly along the circumferential direction of the second piston plate. A plug is arranged in the air release opening. One end of the plug gradually shrinks, so that the plug forms a shape with one end narrow and one end wide. The narrow end of the plug corresponds to the first piston plate, and the outer wall of the wide end of the plug is connected to the inner ring wall of one of the limiting grooves.

[0017] Furthermore, the diameter of the second piston plate is smaller than that of the limiting groove, and there is a gap between the outer ring wall of the second piston plate and the inner ring wall of the limiting groove.

[0018] Furthermore, one side of the sealing ring protrudes, and the protruding part of the sealing ring corresponds to the interface end of the syringe.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. In the present invention, the convex ring separates the piston plates on the left and right sides. When the piston rod is pushed to move leftward, the right piston plate abuts against the convex ring, driving the entire piston ring to move leftward. At this time, a gap is formed between the left piston plate and the convex ring, serving as an air leakage channel for the gas to be discharged through the right end outlet of the syringe. When the piston rod is pulled rightward in the reverse direction, the left piston plate pushes the convex ring to drive the piston ring to move rightward, and the gap closes, enabling the piston ring to restore the sealed state, thereby achieving repeated air extraction from the pipeline and maintaining a long-term attraction force.

[0021] 2. In the present invention, when the protruding surface of the first piston plate made of an elastic material moves rightward, due to the combined action of the negative pressure on the left side and the pulling force on the right side, the protruding surface deforms rightward, prompting the edge of the first piston plate to expand outward and closely fit with the inner wall of the syringe. At the same time, the right side wall of the first piston plate is pressed against the outer wall of the left convex ring under the influence of the pulling force, enhancing the sealing performance of the contact surface, thereby maintaining the negative pressure suction effect and ensuring the stability of the exudate being pumped into the collection bottle through the pipeline.

[0022] 3. In the present invention, when the second piston plate moves rightward until it abuts against the limit groove, the wider end of the plug exactly seals the air leakage opening tightly; when the second piston plate moves leftward towards the convex ring, the air leakage opening gradually corresponds to the narrower part of the plug, and a gap appears between the outer wall and the inner wall, allowing the gas to pass through, thus preventing the negative pressure from causing the first piston plate to be sunken and deformed due to the pressure difference and lack of support in the area corresponding to the air leakage opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the overall structural schematic diagram of the present invention;

[0024] Figure 2 is the external structural schematic diagram of the syringe in the present invention;

[0025] Figure 3 is the internal structural schematic diagram of the syringe in the present invention;

[0026] Figure 4 is the connection structural schematic diagram of the syringe and the piston ring in the present invention;

[0027] Figure 5 is the exploded view of the piston ring in the present invention;

[0028] Figure 6 is the sectional view of the piston ring in the present invention;

[0029] Figure 7 is Figure 6 the enlarged structural view of part A in

[0030] Figure 8 is Figure 6 the enlarged structural view of part B in

[0031] In the figure: 1. Main body of the negative pressure drainage device;

[0032] 2. Syringe; 3. Piston ring; 301. Convex ring; 302. Limit groove; 303. Flange; 4. First piston plate; 5. Second piston plate; 6. Plug; 7. Air leakage opening; 8. Sealing ring; 9. Elastic plate; 10. Snap ring; 11. Convex surface. Specific embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] The present invention provides a technical solution:

[0035] Refer to Figures 1-8 As shown, a negative pressure drainage device for hand wounds includes a negative pressure drainage device main body 1 and a syringe 2. The syringe 2 includes an injection tube and a piston that is hermetically and slidably connected to the injection tube. One end of the piston is connected to a piston rod; the piston includes

[0036] A piston ring 3, the outer wall of the piston ring 3 is hermetically and slidably connected to the inner wall of the injection tube, and at least one convex ring 301 concentric with the piston ring 3 is provided on the inner wall of the piston ring 3, and the convex ring 301 extends towards the center of the piston ring 3;

[0037] Two piston plates, which are arranged at intervals on the piston rod, and the orthographic projections of the two piston plates along the axial direction of the injection tube at least cover the annular opening area of the convex ring 301. At least one air leakage opening 7 is provided on the piston plate close to the piston rod for the piston tube to communicate with the outside when the piston rod is pushed.

[0038] The outer wall of the piston ring 3 is in close contact with the inner wall of the syringe 2. As can be seen in Figure 5 , the piston ring 3 is a ring structure, and the left piston plate blocks the area in the middle of the piston ring 3. Combining with Figure 6 As can be seen, a convex ring 301 is fixedly connected to the inner wall of the piston ring 3, and the two piston plates are separated by the convex ring 301. The left piston plate is located on the left side of the convex ring 301, and the right piston plate is located on the right side of the convex ring 301;

[0039] Combining Figure 3 With Figure 4 As can be seen, a piston rod is also provided in the syringe 2, and the two piston plates are both fixedly installed on the piston rod. The other end of the piston rod extends to the outside of the syringe 2. In this way, when in use, first in Figure 1As can be seen, the interface end of the syringe 2 is on the left side of the syringe 2. When the piston rod is pushed towards the interface end of the syringe 2, the piston rod will drive the two piston plates to move leftward together;

[0040] Next, please look Figure 7 , when the two piston plates move leftward together, when the outer wall of the right piston plate abuts against the outer wall of the convex ring 301, it will push the convex ring 301 and then drive the piston ring 3 to move leftward together. At this time, the left piston plate has moved away from the convex ring 301 and does not contact the outer wall of the convex ring 301, and there is a gap between the outer ring wall of the left piston plate and the inner wall of the piston ring 3. Therefore, when the outer wall of the left piston plate does not contact the convex ring 301, this gap will serve as a gas leakage channel, and then the gas will pass through the gas leakage channel and float towards the outlet at the right end of the syringe 2 through the gas leakage opening 7. At this time, the piston ring 3 is not in a sealed state and cannot generate a thrust on the gas. Therefore, when the piston ring 3 is pushed back, the gas will not be pushed back into the pipeline in the reverse direction;

[0041] When the piston ring 3 reaches near the interface end of the syringe 2 and the pipeline, pull the piston rod to move rightward. At this time, the two piston plates move synchronously. Still Figure 7 from the perspective in

[0042] , the left piston plate moves towards the convex ring 301, while the right piston plate moves rightward, and then drives the piston ring 3 to move rightward together by pushing the convex ring 301 through the left piston plate. At this time, the outer edge of the periphery of the left piston plate abuts against the outer wall of the convex ring 301, closing the gas leakage channel. At this time, the piston ring 3 is in a sealed state, and the gas cannot pass through the left piston plate and the piston ring 3; Figure 1 Therefore, when the piston ring 3 moves rightward, it can normally draw air from the pipeline, so that the exudate in the wound can be drawn out. As can be seen in

[0043] Refer to Figures 6-7 , at least two convex rings 301 concentric with the piston ring 3 are arranged at intervals on the inner ring wall of the piston ring 3. The two convex rings 301 extend towards the center of the piston ring 3 to form a limiting groove 302, and the piston plate on the side close to the piston rod is located in the limiting groove 302.

[0044] It can be seen Figure 7 in

[0045] Refer to Figures 4-7, the two piston plates include a first piston plate 4 and a second piston plate 5. The second piston plate 5 is located within the limit groove 302. The center of the first piston plate 4 bulges towards the interface end of the syringe 2, forming a convex first piston plate 4.

[0046] It can be seen in Figure 6 that the central part of the first piston plate 4 bulges towards the left, and the left side is the interface direction between the syringe 2 and the pipeline. In this way, when the first piston plate 4 moves to the right, the pulling force and negative pressure will make the right side wall of the edge of the first piston plate 4 squeeze more tightly against the outer wall of the left convex ring 301. The first piston plate 4 is elastic, and the protruding surface of the first piston plate 4 faces left. In this way, when the first piston plate 4 is subjected to the squeezing force from the left negative pressure and the pulling force from the right, the protruding surface of the first piston plate 4 will deform to the right, causing the edge of the first piston plate 4 to squeeze against the inner wall of the syringe 2. The extension of the first piston plate 4 makes the first piston plate 4 fit more closely with the syringe 2, further ensuring that when the first piston plate 4 and the piston ring 3 move to the right, gas will not leak from the contact surface between the first piston plate 4 and the convex ring 301;

[0047] First, the second piston plate 5 will move within the limit groove 302. When the outer wall of the second piston plate 5 abuts against the outer wall of the left convex ring 301, it will push the convex ring 301 and then push the piston ring 3 to move to the left together. At this time, the first piston plate 4 has moved away from the left convex ring 301 and does not contact the outer wall of the convex ring 301. When the outer wall of the first piston plate 4 does not contact the left convex ring 301, the gas will pass through the first piston plate 4 and then float towards the outlet at the right end of the syringe 2 through the air release opening 7 on the second piston plate 5. At this time, the piston ring 3 and the first piston plate 4 are not in a sealed state and cannot generate a thrust on the gas. Therefore, the gas will not be pushed back into the pipeline when the piston ring 3 is pushed back;

[0048] When the piston ring 3 reaches near the interface end between the syringe 2 and the pipeline, pull the pull rod to move to the right. At this time, the first piston plate 4 and the second piston plate 5 move synchronously. Still from the perspective of Figure 7 , the first piston plate 4 moves towards the left convex ring 301, while the second piston plate 5 moves to the right along the limit groove 302 and abuts against the right convex ring 301, and then drives the piston ring 3 to move to the right by pushing the convex ring 301. At this time, the outer edge of the first piston plate 4 abuts against the outer wall of the left convex ring 301, closing the air release channel. At this time, the piston ring 3 is in a sealed state and the gas cannot pass through the first piston plate 4.

[0049] Refer to Figures 7-8, an elastic plate 9 is arranged on the periphery of the first piston plate 4. The elastic plate 9 is elastic. One end of the elastic plate 9 is fixedly connected to the outer ring wall of the first piston plate 4, and the other end extends towards the convex ring 301 and forms an angle with the outer ring wall of the first piston plate 4. There is a gap between the outer ring wall of the elastic plate 9 and the outer ring wall of the convex ring 301;

[0050] It further includes a snap ring 10 arranged on one side of the angle. One end of the snap ring 10 is fixedly connected to the outer wall of the convex ring 301, and the other end corresponds to the angle. The inner ring walls of the snap ring 10 are arranged in parallel, and there is a height difference at both ends of the outer ring wall of the snap ring 10 to form a convex surface 11.

[0051] It can be seen in Figure 8 that an angle is formed between the elastic plate 9 and the outer ring wall of the first piston plate 4, and this angle corresponds to the snap ring 10. When the first piston plate 4 moves to the right, the angle will be sleeved on the snap ring 10. When the snap ring 10 is inserted into the angle, since the convex surface 11 on the outer ring surface of the snap ring 10 gradually expands upward from left to right, after the snap ring 10 enters the angle, the convex surface 11 will push the periphery of the elastic plate 9 towards the inner wall of the syringe 2, that is, the side of the elastic plate 9 away from the first piston plate 4 will deform, and at this time the angle becomes larger, the outer ring wall of the elastic plate 9 expands outward, and the outer ring wall of the elastic plate 9 abuts against the syringe 2, further increasing the sealing performance of the gap between the first piston plate 4 and the piston ring 3. At the same time, the snap ring 10 can also be horizontally arranged at the connection between the first piston plate 4 and the convex ring 301, further preventing gas from passing through the weak gap;

[0052] The elastic force of the elastic plate 9 is very small. After the first piston plate 4 moves to the left, the angle will gradually move out of the snap ring 10. After the elastic plate 9 moves away from the snap ring 10 and the air leakage channel is opened, the second piston plate 5 will contact the left convex ring 301 and push it to move together with the piston ring 3. At the same time, when the piston rod is pulled by hand, since the finger supports the piston rod and the syringe 2, the first piston plate 4 will not rebound. After the piston rod is released, the deformed first piston plate 4 will rebound into a bulging state again. At this time, the angle will also relax the clamping of the snap ring 10, so that the snap ring 10 will not be clamped too tightly with the angle;

[0053] When the bulging first piston plate 4 deforms and expands outward, the outer ring surface of the first piston plate 4 will closely abut against the inner ring wall of the snap ring 10. Therefore, at this time, the angle will be clamped relatively tightly with the snap ring 10.

[0054] Refer to Figure 8 , a sealing ring 8 is fixedly installed on the outer ring wall of the elastic plate 9, and there is a gap between the outer ring surface of the sealing ring 8 and the outer ring wall of the convex ring 301.

[0055] The sealing ring 8 is fixed on the outer ring wall of the elastic plate 9. When the outer peripheral edge of the elastic plate 9 expands outward, it will drive the sealing ring 8 to squeeze against the inner wall of the syringe 2. The sealing ring 8 is made of rubber material and can fit more closely to the inner wall of the syringe 2. In an ideal state, the outer surface of the outwardly expanding and deforming elastic plate 9 should be in close contact with the inner wall of the syringe 2 to prevent gas leakage;

[0056] If the outer expansion of the elastic plate 9 is not smooth or not round enough, gaps of different sizes will be formed between its outer surface and the inner wall of the syringe 2, and gas will leak through these gaps, thus destroying the sealing effect. Therefore, the rubber sealing ring 8 has excellent elasticity and can undergo large deformations when being squeezed. When the outer expansion of the elastic plate 9 is not smooth or not round enough, the sealing ring 8 can fill the gaps between the irregular parts and the inner wall of the syringe 2 through its own elastic deformation, thus maintaining a good sealing effect.

[0057] Refer to Figures 6-8 , a flange 303 is fixedly installed at one end of the piston ring 3 corresponding to the interface of the syringe 2. The sealing ring 8 and the snap ring 10 are both located within the area surrounded by the flange 303. There are gaps between the outer ring surfaces of the sealing ring 8 and the snap ring 10 and the inner ring wall of the flange 303. The flange 303 has elasticity.

[0058] In Figure 7 , it can be seen that the flange 303 protrudes from the left convex ring 301 and covers the first piston plate 4 therein. In this way, when the sealing ring 8 deforms and expands outward, it will directly squeeze the inner wall of the flange 303. After being squeezed, the outer wall of the flange 303 will tightly contact the inner wall of the syringe 2, which not only improves the sealing performance between the outer wall of the piston ring 3 and the inner wall of the syringe 2, but also makes the first piston plate 4 and the piston ring 3 move more synchronously. If the first piston plate 4 directly contacts the inner wall of the syringe 2 through the sealing ring 8, then when the first piston plate 4 and the piston ring 3 move, they may move out of sync due to different frictions, which will increase the risk of forming gaps;

[0059] At the same time, the repeated reciprocating movement of the piston ring 3 and the inner wall of the syringe 2 will cause wear due to friction. The flange 303 can be in close contact with the inner wall of the syringe 2 to maintain good sealing performance.

[0060] Refer to Figures 5-7 , there are multiple air release openings 7. The air release openings 7 are opened on the second piston plate 5. The multiple air release openings 7 extend equidistantly along the circumference of the second piston plate 5. A plug 6 is arranged in the air release openings 7. One end of the plug 6 gradually tapers, so that the plug 6 forms a shape with one end narrow and one end wide. The narrow end of the plug 6 corresponds to the first piston plate 4, and the outer wall of the wide end of the plug 6 is fixedly connected to the inner ring wall of one of the limiting grooves 302.

[0061] In Figure 5As can be seen, four air release openings 7 are arranged at equal intervals in the circumferential direction around the second piston plate 5. A plug 6 is provided in each air release opening 7, and then Figure 7 From the perspective of Figure 7 , it can be seen that the right end of the plug 6 is wider than the left end, and the diameter of the right end of the plug 6 is the same as the diameter of the air release opening 7. In this way, when the second piston plate 5 abuts against the right-side limiting groove 302, the end width of the plug 6 just blocks the air release opening 7. When the second piston plate 5 moves towards the left convex ring 301, the air release opening 7 will gradually move towards the narrow end of the plug 6. At this time, there is a gap between the outer wall of the plug 6 and the inner wall of the air release opening 7. Then, since the moving direction at this time is to the left, the air release channel is opened, allowing gas to flow through the gap between the air release opening 7 and the plug 6;

[0062] This is to prevent the area of the first piston plate 4 corresponding to the air release opening 7 from being deformed by negative pressure when the negative pressure acts on the first piston plate 4. This is because, in the negative pressure state, a pressure difference is formed on both sides of the first piston plate 4 (external atmospheric pressure > internal negative pressure). The area of the air release opening 7 lacks the support of solid material and becomes a mechanical weak point. Local stress concentration will cause the first piston plate 4 to be recessed and deformed towards the air release opening 7.

[0063] Refer to Figure 7 As shown in Figure 7 , the diameter of the second piston plate 5 is smaller than that of the limiting groove 302, and there is a gap between the outer ring wall of the second piston plate 5 and the inner ring wall of the limiting groove 302.

[0064] The outer ring wall of the second piston plate 5 does not contact the inner wall of the limiting groove 302. In this way, when the second piston plate 5 moves along the limiting groove 302, it will not prematurely push the piston ring 3 due to friction, but will wait until the second piston plate 5 contacts the two convex rings 301 before pushing the convex rings 301 and the piston ring 3 to move.

[0065] Refer to Figure 8 As shown in Figure 8 , one side of the sealing ring 8 is convexly arranged, and the convex part of the sealing ring 8 corresponds to the interface end of the syringe 2.

[0066] Figure 8 As can be seen in Figure 8 , the left side surface of the sealing ring 8 protrudes to the left, and the protruding surface corresponds to the negative pressure and contacts the negative pressure. The protruding surface can provide a certain amount of elastic support for the sealing ring 8, making it not easily sucked flat or damaged in the negative pressure state, and dispersing the acting force of the negative pressure on the sealing ring 8, enhancing its stability and reliability in the negative pressure environment.

Claims

1. A negative pressure drainage device for hand wounds, comprising a negative pressure drainage device main body (1) and a syringe (2). The syringe (2) includes an injection tube and a piston hermetically and slidably connected to the injection tube. One end of the piston is connected to a piston rod; characterized in that, The piston includes, a piston ring (3), the outer ring wall of the piston ring (3) is in sealed sliding connection with the tube wall of the injection tube, and at least one convex ring (301) concentric with the piston ring (3) is arranged on the inner ring wall of the piston ring (3), and the convex ring (301) extends towards the center of the piston ring (3); two piston plates, which are arranged on the piston rod at intervals, and the orthographic projections of the two piston plates along the axial direction of the injection tube at least cover the ring opening area of the convex ring (301). At least one air release opening (7) is arranged on the piston plate close to the piston rod for the piston tube to communicate with the outside when the piston rod is pushed.

2. The hand wound negative pressure drainage device according to claim 1, wherein: At least two convex rings (301) concentric with the piston ring (3) are arranged on the inner ring wall of the piston ring (3) at intervals, and the two convex rings (301) extend towards the center of the piston ring (3) to form a limiting groove (302), and the piston plate on the side close to the piston rod is located in the limiting groove (302).

3. The hand wound negative pressure drainage device according to claim 2, characterized in that: The two piston plates include a first piston plate (4) and a second piston plate (5). The second piston plate (5) is located in the limiting groove (302). The center of the first piston plate (4) bulges towards the interface end of the syringe (2) to form a convex first piston plate (4).

4. The hand wound negative pressure drainage device according to claim 3, wherein: An elastic plate (9) is arranged on the periphery of the first piston plate (4). The elastic plate (9) has elasticity. One end of the elastic plate (9) is connected to the outer ring wall of the first piston plate (4), and the other end extends towards the direction of the convex ring (301) and forms an included angle with the outer ring wall of the first piston plate (4). There is a gap between the outer ring wall of the elastic plate (9) and the outer ring wall of the convex ring (301); A snap ring (10) is further included, which is arranged on one side of the included angle. One end of the snap ring (10) is connected to the outer wall of the convex ring (301), and the other end corresponds to the included angle. The inner ring wall of the snap ring (10) is arranged in parallel, and there is a height difference at both ends of the outer ring wall of the snap ring (10) to form a convex surface (11).

5. The hand wound negative pressure drainage device according to claim 4, characterized in that: A sealing ring (8) is installed on the outer ring wall of the elastic plate (9), and there is a gap between the outer ring surface of the sealing ring (8) and the outer ring wall of the convex ring (301).

6. The hand wound negative pressure drainage device according to claim 5, characterized in that: A flange (303) is installed at one end of the piston ring (3) corresponding to the interface of the syringe (2). The sealing ring (8) and the snap ring (10) are both located in the area surrounded by the flange (303), and there are gaps between the outer ring surfaces of the sealing ring (8) and the snap ring (10) and the inner ring wall of the flange (303).

7. The hand wound negative pressure drainage device according to claim 6, characterized in that: There are multiple air release openings (7). The air release openings (7) are opened on the second piston plate (5). The multiple air release openings (7) extend equidistantly along the circumferential direction of the second piston plate (5). A plug (6) is arranged in the air release opening (7). One end of the plug (6) gradually contracts, so that the plug (6) forms a shape with one end narrow and one end wide. The narrow end of the plug (6) corresponds to the first piston plate (4), and the outer wall of the wide end of the plug (6) is connected to the inner ring wall of one of the limiting grooves (302).

8. The hand wound negative pressure drainage device according to claim 7, characterized in that: The diameter of the second piston plate (5) is smaller than that of the limiting groove (302), and there is a gap between the outer ring wall of the second piston plate (5) and the inner ring wall of the limiting groove (302).

9. The hand wound negative pressure drainage device according to claim 8, characterized in that: One side of the sealing ring (8) protrudes, and the protruding part of the sealing ring (8) corresponds to the interface end of the syringe (2).

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