Pneumatic needleless injector

Abstract

The present application relates to the technical field of medical devices, in particular to a kind of pneumatic needleless injector, it includes: shell;Liquid path component, including drug liquid pump cylinder, striker, first check valve, second check valve and jet head;Gas path component, including pneumatic piston and pilot two-position five-way electromagnetic valve;Circuit component, including power supply, trigger switch and anti-misoperation switch, trigger switch and anti-misoperation switch are connected in series, and are electrically connected with power supply and pilot two-position five-way electromagnetic valve;Handle component, including handle and handle seat;Solve the machining difficulty big, complex structure, heavy and the problem of operation jam of existing pneumatic continuous needleless injector.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically a pneumatic needleless injector. Background Technology

[0002] Needle injection is a traditional method of drug administration, but it has several inherent drawbacks. Specifically, after the drug solution is injected into the body tissue, its distribution is relatively concentrated and its diffusion is slow, which is not conducive to the rapid absorption of the drug by the human or animal body. At the same time, needle injection is prone to causing abscesses at the injection site, and it can cause pain and panic to the recipient. In addition, when carrying out collective disease prevention in large-scale farms, frequent needle changes are required, which not only increases the risk of cross-infection between animals, but also increases costs and reduces production efficiency.

[0003] To address the aforementioned issues, continuous needle-free injectors have been developed. Needle-free injections eliminate the need to puncture the skin, avoiding problems such as infection and pain. For collective disease prevention in large-scale farms, continuous needle-free injectors can simplify procedures, reduce the risk of cross-infection, and improve production efficiency. Therefore, continuous needle-free injectors have broad application prospects in the medical and aquaculture fields.

[0004] Currently, a similar type of continuous needle-free injector is a pneumatic continuous needle-free injector controlled by a pneumatically operated slide valve. This injector includes a main body and a pilot valve installed within the control valve housing of the main body. In use, triggering the pilot valve causes compressed gas to drive the pneumatically operated slide valve, which in turn causes a cylinder to drive a plunger pump to pressurize the medication. Specifically, the pilot valve is triggered by a trigger.

[0005] However, the existing pneumatic continuous needleless injectors have the following shortcomings: First, the outer shell is machined as a single piece, leading to a complex manufacturing process. Precise positioning and fitting of the two shells are required during processing to ensure the syringe's sealing performance and stability. However, factors such as material deformation and processing errors make it difficult to ensure that each shell meets the expected precision requirements, resulting in a low yield.

[0006] Secondly, its quick-opening valve body adopts a non-standard design, with a relatively complex structure, requiring more precise operation and maintenance, resulting in higher production costs.

[0007] Third, the pneumatically controlled slide valve and the drive plunger pump are integrated into the same housing, resulting in a relatively heavy product. Operators are prone to fatigue when holding this heavy syringe for extended periods, which can negatively impact work efficiency.

[0008] Fourth, its safety locking handle mechanism is complex and prone to jamming during use. Summary of the Invention

[0009] In order to solve the problems of high manufacturing difficulty, complex structure, heavy weight and operation jamming of existing pneumatic continuous needleless injectors, the present invention provides a pneumatic needleless injector.

[0010] This invention is achieved using the following technical solution: A pneumatic needleless injector, comprising: shell; The liquid circuit assembly includes a liquid pump column, a striking pin, a first one-way valve, a second one-way valve, and a jet nozzle. The liquid pump column is fixed to the front end of the housing. One end of the striking pin extends into the liquid pump column and forms a dynamic seal with the liquid pump column. The other end of the striking pin extends out of the liquid pump column. The first one-way valve is connected between the liquid interface of the liquid pump column and the liquid source. The second one-way valve is connected between the liquid interface of the liquid pump column and the jet nozzle. The second one-way valve is connected to the jet nozzle through a filler core. The pneumatic circuit assembly includes a pneumatic piston and a pilot-operated two-position five-way solenoid valve. The pneumatic piston is slidably disposed inside the housing and is connected to the extended end of the firing pin. The inner wall of the housing and the pneumatic piston together form a first air chamber and a second air chamber. The pilot-operated two-position five-way solenoid valve is disposed outside the housing and is connected to the first air chamber through a first air pipe and to the second air chamber through a second air pipe. The circuit components include a power supply, a trigger switch, and an anti-accidental contact switch. The trigger switch and the anti-accidental contact switch are connected in series and then electrically connected to the power supply and the pilot-operated two-position five-way solenoid valve. The handle assembly includes a handle and a handle base, the handle base being fixed to the housing, the handle being connected to the handle base, and a trigger switch being mounted on the handle base.

[0011] Furthermore, the outer shell is cylindrical, with its inner cylindrical face stepped at both ends, the front diameter being smaller than the rear diameter, and its outer cylindrical face having multiple mounting steps; the liquid pump column is fixedly connected to the front end of the outer shell by studs, the studs being connected to the inner threads of the outer shell through their external threads, and the end face of the studs having multiple evenly distributed threaded holes, the liquid pump column being fixedly connected to the studs by hexagonal socket head cap screws.

[0012] Furthermore, the pneumatic piston includes a piston cylinder, a striker clip, and a locking nut. The striker clip is fixed to the piston cylinder by the locking nut, and the protruding end of the striker is connected to the striker clip. The pneumatic piston is provided with a second sealing ring and a third sealing ring, which are respectively disposed on the outer circumferential surface of the piston cylinder. The second sealing ring is located between the first air chamber and the second air chamber, and is used to isolate the first air chamber from the second air chamber. The third sealing ring is located on the side of the second air chamber away from the first air chamber, and is used to seal the second air chamber.

[0013] Furthermore, the liquid circuit assembly also includes a three-way valve, wherein the first port of the three-way valve is connected to the first check valve, the second port is connected to the second check valve, and the third port is connected to the liquid interface of the liquid pump column.

[0014] Furthermore, the source of the drug solution is a disposable syringe, which is connected to the first one-way valve via a tubing; the outer shell is fixed with an elastic syringe clamp, in which the disposable syringe is held and fixed to the outer shell with screws.

[0015] Furthermore, the liquid pump column is also provided with a nylon sliding sleeve, a support ring and a Y-shaped sealing ring. The nylon sliding sleeve and the support ring are sleeved on the outer periphery of the firing pin, and the Y-shaped sealing ring is set between the firing pin and the liquid pump column. The rear end of the liquid pump column is equipped with a liquid pump end cap.

[0016] Furthermore, the tail end of the outer casing is provided with a liquid volume adjustment module, which includes an end cap, a buffer pad, and a first sealing ring. The end cap is fixedly connected to the tail end of the outer casing by threads, the buffer pad is disposed on the inner end face of the end cap, and the first sealing ring is disposed between the end cap and the outer casing.

[0017] Furthermore, it also includes an anti-accidental touch mechanism, which includes: The guide seat is fixed to the housing, and the anti-accidental touch switch is installed at the first end of the guide seat; An anti-accidental contact rod is slidably installed at the second end of the guide seat, and the first end of the anti-accidental contact rod is positioned opposite to the anti-accidental contact switch. A sliding seat is slidably sleeved on the outer surface of the liquid pump column, and the sliding seat is fixed to the second end of the anti-accidental contact rod; Anti-slip sleeve, the sliding sleeve is located on the outside of the jet nozzle and is connected to the sliding seat; The spring is slidably sleeved on the outer surface of the liquid pump column, with its front end fixed to the tail of the sliding seat and its rear end fixed to the stepped end face provided on the outer cylindrical surface of the liquid pump column.

[0018] Furthermore, the air supply port of the pilot-operated two-position five-way solenoid valve is connected to the gas storage cylinder through a pressure regulating valve and a pressure reducing bottle; the pilot-operated two-position five-way solenoid valve is fixed to the gas storage cylinder by a solenoid valve fixing clamp; the first air pipe and the second air pipe are connected to the pilot-operated two-position five-way solenoid valve after being collected and tightened by an air pipe sleeve.

[0019] Furthermore, the first air chamber is connected to the first air tube via a first quick connector, and the second air chamber is connected to the second air tube via a second quick connector.

[0020] This invention provides a pneumatic needle-free injector, which has the following advantages compared with the prior art: 1. An externally mounted pilot-operated two-position five-way solenoid valve is used instead of the traditional built-in pneumatic sliding valve, which greatly reduces the weight of the handheld part, reduces operator hand fatigue, and at the same time ensures stable jet parameters and good repeatability of multiple injections.

[0021] 2. The circuit components feature a series connection between the trigger switch and the anti-accidental trigger switch. The circuit can only be activated when both switches are triggered simultaneously, effectively preventing accidental activation and improving safety.

[0022] 3. All functional components are integrated and installed on the outer shell with screws to form an integrated handheld device. The structure is compact, easy to disassemble and assemble, easy to clean and disinfect, and reduces the processing difficulty, improves the yield rate, and reduces costs.

[0023] 4. The liquid volume adjustment module uses end caps of different lengths. By changing the end caps, the stroke of the pneumatic piston can be adjusted, enabling rapid switching of the drug dosage. It is easy to operate and suitable for different injection needs.

[0024] 5. The anti-accidental touch mechanism converts skin contact action into switch triggering through the mechanical linkage of the anti-slip sleeve, sliding seat, and anti-accidental touch rod. The structure is reliable and avoids the problem of jamming caused by complex mechanical safety devices. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention.

[0026] Figure 2 This is a cross-sectional view of the structure of the present invention.

[0027] Figure 3 This is a schematic diagram of the air source and the pilot-operated two-position five-way solenoid valve of the present invention.

[0028] Figure 4 This is a cross-sectional view of the pharmaceutical pump column of the present invention.

[0029] Figure 5 This is a cross-sectional view of the end cap of the present invention.

[0030] Figure 6 This is a cross-sectional view of the pneumatic piston of the present invention.

[0031] Figure 7 This is a cross-sectional view of the anti-accidental touch mechanism of the present invention.

[0032] In the diagram: 1. Disposable syringe; 2. Syringe clamp; 3. Tube; 4. First one-way valve; 5. Anti-slip sleeve; 6. Sliding seat; 7. Anti-accidental contact rod; 8. Anti-accidental contact switch; 9. Trigger switch; 10. Handle; 11. Handle seat; 12. Housing; 13. End cap; 14. Piston cylinder; 15. Firing pin clip; 16. Firing pin; 17. First quick connector; 18. Second quick connector; 19. First air tube; 20. Second air tube; 21. Air tube sleeve; 22. Pilot-operated two-position five-way solenoid valve; 23. Solenoid valve retainer. 24. Hoop; 25. Pressure reducing bottle; 26. Pressure regulating valve; 27. Gas storage bottle; 28. Pressure gauge; 29. ​​Medicine pump end cap; 30. Nylon sleeve; 31. Support ring; 32. Y-type sealing ring; 33. Stud; 34. Medicine pump column; 35. T-joint; 36. Second check valve; 37. Filler core; 38. Jet nozzle; 39. First sealing ring; 40. Buffer pad; 41. Locking nut; 42. Second sealing ring; 43. Third sealing ring; 44. Guide seat; 45. Spring; 46. First air chamber; 47. Second air chamber. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. This invention provides a pneumatic needle-free injector, which is a continuous needle-free injector for injecting drugs into animals, such as... Figures 1 to 7 As shown, it includes: The outer shell 12 is made of aluminum alloy and is cylindrical. Its inner cylindrical surface is stepped at both ends, with the front diameter being smaller than the rear diameter. Its outer cylindrical surface has multiple mounting steps.

[0034] The liquid circuit assembly includes a liquid pump column 33, a striking pin 16, a first one-way valve 4, a second one-way valve 35, and a jet nozzle 37. The liquid pump column 33 is fixedly connected to the front end of the housing 12 by a stud 32. The stud 32 is connected to the housing 12 by its external thread engaging with the internal thread of the housing 12. The end face of the stud 32 has multiple evenly distributed threaded holes. The liquid pump column 33 and the stud 32 are fixedly connected by hexagonal screws. This structure can lock the liquid pump column 33 and the housing 12 at the same time as connecting the liquid interface of the liquid pump column 33 with the liquid outlet of the liquid source. One end of the striking pin 16 extends into the liquid pump column 33 and forms a dynamic seal with the liquid pump column 33. The other end of the striking pin 16 extends out of the liquid pump column 33. The first one-way valve 4 is connected between the liquid inlet of the liquid pump column 33 and the liquid source, allowing the liquid to flow out only from the liquid source in one direction. The second one-way valve 35 is connected between the liquid inlet of the liquid pump column 33 and the jet nozzle 37, allowing the liquid to be ejected only from the jet nozzle 37 in the direction of the liquid path. The second one-way valve 35 is connected to the jet nozzle 37 through a filler core 36. The jet nozzle 37 is a micro-orifice nozzle. The liquid source is a disposable syringe 1, which is connected to the first one-way valve 4 through a flexible tube 3. An elastic syringe clamp 2 is fixed on the outer shell 12, and the disposable syringe 1 is clamped in the syringe clamp 2 and fixed to the outer shell 12 with screws.

[0035] The fluid circuit assembly also includes a three-way valve 34. The first port of the three-way valve 34 is connected to the first one-way valve 4, the second port is connected to the second one-way valve 35, and the third port is connected to the liquid inlet of the liquid pump column 33. The three ports are connected by threads. The liquid pump column 33 is also provided with a nylon sleeve 29, a support ring 30, and a Y-shaped sealing ring 31. The nylon sleeve 29 and the support ring 30 are sleeved on the outer periphery of the impact pin 16, providing guidance and support for the impact pin 16. The Y-shaped sealing ring 31 is disposed between the impact pin 16 and the liquid pump column 33, serving to isolate gas and liquid. A liquid pump end cap 28 is installed at the rear end of the liquid pump column 33. The liquid pump end cap 28 is connected to the liquid pump column 33 by threads, providing a fixing function for the nylon sleeve 29.

[0036] The pneumatic assembly includes a pneumatic piston and a pilot-operated two-position five-way solenoid valve 22. The pneumatic piston is slidably disposed inside the housing 12 and is connected to the protruding end of the striking pin 16. The inner wall of the housing 12 and the pneumatic piston together form a first air chamber 45 and a second air chamber 46. The pilot-operated two-position five-way solenoid valve 22 is disposed outside the housing 12 and is connected to the first air chamber 45 via a first air pipe 19 and to the second air chamber 46 via a second air pipe 20. The pneumatic piston includes a piston rod 14, a striking pin latch 15, and a locking nut 40. The striking pin latch 15 is fixed to the piston rod 14 by the locking nut 40, and the protruding end of the striking pin 16 is connected to the striking pin latch 15. The pneumatic piston is provided with a second sealing ring 41 and a third sealing ring 42, which are respectively disposed on the outer circumferential surface of the piston cylinder 14. The second sealing ring 41 is located between the first air chamber 45 and the second air chamber 46, and is used to isolate the first air chamber 45 from the second air chamber 46. The third sealing ring 42 is located on the side of the second air chamber 46 away from the first air chamber 45, and is used to seal the second air chamber 46. The first air chamber 45 is connected to the first air pipe 19 through the first quick connector 17, and the second air chamber 46 is connected to the second air pipe 20 through the second quick connector 18.

[0037] The air supply port of the pilot-operated two-position five-way solenoid valve 22 is connected to the gas storage cylinder 26 via a pressure regulating valve 25 and a pressure reducing bottle 24. A pressure gauge 27 is installed on the gas storage cylinder 26. Gas from the gas storage cylinder 26 enters the pressure reducing bottle 24 through the pressure regulating valve 25, and the depressurized gas then enters the pilot-operated two-position five-way solenoid valve 22. The pilot-operated two-position five-way solenoid valve 22 is fixed to the gas storage cylinder 26 by a solenoid valve fixing clamp 23. The first air pipe 19 and the second air pipe 20 are connected to the pilot-operated two-position five-way solenoid valve 22 after being secured and tightened by an air pipe sleeve 21.

[0038] The tail end of the outer casing 12 is provided with a liquid volume adjustment module, which includes an end cap 13, a buffer pad 39, and a first sealing ring 38. The end cap 13 is fixedly connected to the tail end of the outer casing 12 by threads. The buffer pad 39 is disposed on the inner end face of the end cap 13, and the first sealing ring 38 is disposed between the end cap 13 and the outer casing 12. The end cap 13 has at least two different lengths. After the end caps 13 of different lengths are screwed into the outer casing 12, their inner end faces are located at different axial positions within the outer casing 12, thereby limiting the pneumatic piston to have different strokes and thus controlling the amount of inhaled liquid. For example, the two different lengths of the end cap 13 correspond to 1 ml and 2 ml of liquid, respectively.

[0039] The circuit components include a power supply, a trigger switch 9, and an anti-accidental contact switch 8. The trigger switch 9 and the anti-accidental contact switch 8 are connected in series and are electrically connected to the power supply and the pilot-operated two-position five-way solenoid valve 22. The power supply is a battery. Except for the battery, all other circuit components are integrated into the monolithic pneumatic needle-free injector.

[0040] The handle assembly includes a handle 10 and a handle base 11. The handle base 11 is fixed to the housing 12. The handle 10 is connected to the handle base 11. A trigger switch 9 is installed on the handle base 11.

[0041] It also includes an anti-accidental touch mechanism, which comprises: a guide seat 43, fixed to the outer shell 12, with the anti-accidental touch switch 8 installed at the first end of the guide seat 43; an anti-accidental touch rod 7, slidably passing through the second end of the guide seat 43, with the first end of the anti-accidental touch rod 7 opposite to the anti-accidental touch switch 8; a sliding seat 6, slidably sleeved on the outer surface of the liquid pump column 33, with the sliding seat 6 fixed to the second end of the anti-accidental touch rod 7; an anti-slip sleeve 5, slidably sleeved on the outside of the jet nozzle 37 and connected to the sliding seat 6; and a spring 44, slidably sleeved on the outer surface of the liquid pump column 33, with its front end fixed to the tail of the sliding seat 6 and its rear end fixed to the stepped end face provided on the outer cylindrical surface of the liquid pump column 33. The two ends of the sliding seat 6 are limited to the tee 34 and the liquid pump column 33, respectively, so that it can only move along the axial direction of the liquid pump column 33. In its natural state, the sliding seat 6 is pressed tightly against the end face of the tee 34 by the elastic force of the spring 44. The anti-slip sleeve 5 has a groove machined at one end, which is screwed into the sliding seat 6. The other end has an anti-slip groove machined on it. After installation, the front end of the anti-slip groove is flush with the front end of the jet nozzle 37. The anti-slip sleeve 5 can move axially, pushing the sliding seat 6, thereby driving the anti-accidental contact rod 7 to move along the guide seat 43 towards the anti-accidental contact switch 8 until the anti-accidental contact switch 8 is triggered.

[0042] The pneumatic needleless injector provided by this invention, except for the air source, battery and pilot-operated two-position five-way solenoid valve 22, has all other functional components integrated and installed on the outer shell 12 by screws, forming an integrated handheld device with the characteristics of compact structure, simple operation and easy cleaning and disinfection.

[0043] The working process of this invention is as follows: Compressed gas exits from gas cylinder 26, passes through pressure regulating valve 25 into pressure reducing cylinder 24, and then flows to pilot-operated two-position five-way solenoid valve 22.

[0044] When the trigger switch 9 is in the non-firing state, the air supply port of the pilot-operated two-position five-way solenoid valve 22 is connected to the second air pipe 20, and compressed gas enters the second air chamber 46, pushing the pneumatic piston towards the tail of the outer casing 12 and causing the firing pin 16 to move backward, thereby drawing the liquid from the disposable syringe 1 through the first one-way valve 4 and the three-way valve 34 into the liquid pump column 33, completing the liquid aspiration. At this time, the pneumatic piston remains in the initial position and no longer consumes air, waiting for firing.

[0045] When firing is required, the anti-slip sleeve 5 is placed on the skin surface to be injected, causing it to move the anti-accidental contact rod 7 to contact the anti-accidental contact switch 8 (at this time, the anti-accidental contact switch 8 is triggered). Then, the trigger switch 9 is pressed. Since the two switches are connected in series, the circuit is connected, and the pilot-operated two-position five-way solenoid valve 22 is activated. Its air supply port is switched to connect with the first air pipe 19 (the exhaust port is connected with the second air pipe 20). Compressed gas enters the first air chamber 45, which pushes the pneumatic piston forward quickly. The pneumatic piston drives the firing pin 16 to move forward quickly through the firing pin buckle 15, so that the liquid in the liquid pump column 33 passes through the three-way valve 34, the second one-way valve 35, and the filling core 36, and is ejected at high speed from the jet nozzle 37 in the form of a jet, piercing the skin. The liquid enters the subcutaneous or muscle tissue, realizing needle-free injection. At this time, the operator can judge that the injection has been completed by hearing the jet sound and the slight recoil force at the nozzle. The jet speed of needle-free injection is extremely fast (usually sub-millisecond level), and the liquid discharge time is very short (<0.1 seconds).

[0046] After injection, the jet nozzle 37 is removed from the injection site, the trigger switch 9 is released, the pilot-operated two-position five-way solenoid valve 22 returns to the non-triggered state, the compressed gas re-enters the second air chamber 46, the pneumatic piston returns to the initial position, the liquid pump column 33 completes the liquid pumping again, maintains the initial state, and waits for the next firing.

[0047] When the end caps 13 of different lengths are replaced, the initial position of the pneumatic piston changes, thereby changing the stroke of the pneumatic piston, which in turn changes the stroke of the firing pin 16, enabling a single syringe to complete different injection volumes.

[0048] Multiple mounting steps on the outer cylindrical surface of the housing 12 can be used to fix the guide seat 43, syringe clamp 2, handle seat 11, first quick connector 17 and second quick connector 18.

[0049] In the description of this invention, it should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pneumatic needleless injector, characterized in that, include: Outer shell (12); The liquid circuit assembly includes a liquid pump column (33), a striker (16), a first check valve (4), a second check valve (35), and a jet nozzle (37). The liquid pump column (33) is fixed to the front end of the housing (12). One end of the striker (16) extends into the liquid pump column (33) and forms a dynamic seal with the liquid pump column (33). The other end of the striker (16) extends out from the liquid pump column (33). The first check valve (4) is connected between the liquid interface of the liquid pump column (33) and the liquid source. The second check valve (35) is connected between the liquid interface of the liquid pump column (33) and the jet nozzle (37). The second check valve (35) is connected to the jet nozzle (37) through a filler core (36). The pneumatic assembly includes a pneumatic piston and a pilot-operated two-position five-way solenoid valve (22). The pneumatic piston is slidably disposed inside the housing (12) and is connected to the protruding end of the striker (16). The inner wall of the housing (12) and the pneumatic piston together form a first air chamber (45) and a second air chamber (46). The pilot-operated two-position five-way solenoid valve (22) is disposed outside the housing (12) and is connected to the first air chamber (45) through a first air pipe (19) and to the second air chamber (46) through a second air pipe (20). The circuit components include a power supply, a trigger switch (9) and an anti-misoperation switch (8). The trigger switch (9) and the anti-misoperation switch (8) are connected in series and then electrically connected to the power supply and the pilot-operated two-position five-way solenoid valve (22). The handle assembly includes a handle (10) and a handle base (11), the handle base (11) is fixed to the housing (12), the handle (10) is connected to the handle base (11), and a trigger switch (9) is installed on the handle base (11).

2. The pneumatic needleless injector according to claim 1, characterized in that: The outer shell (12) is cylindrical, with the inner cylindrical face being stepped. The diameter of the front end is smaller than that of the rear end, and the outer cylindrical face is provided with multiple mounting steps. The liquid pump column (33) is fixedly connected to the front end of the outer shell (12) by a stud (32). The stud (32) is connected to the inner thread of the outer shell (12) by its external thread. The end face of the stud (32) is provided with multiple evenly distributed threaded holes. The liquid pump column (33) and the stud (32) are fixedly connected by an internal hexagon screw.

3. The pneumatic needleless injector according to claim 1, characterized in that: The pneumatic piston includes a piston cylinder (14), a striker clip (15), and a locking nut (40). The striker clip (15) is fixed to the piston cylinder (14) by the locking nut (40), and the protruding end of the striker (16) is connected to the striker clip (15). The pneumatic piston is provided with a second sealing ring (41) and a third sealing ring (42). The second sealing ring (41) and the third sealing ring (42) are respectively disposed on the outer circumferential surface of the piston cylinder (14). The second sealing ring (41) is located between the first air chamber (45) and the second air chamber (46) to isolate the first air chamber (45) and the second air chamber (46). The third sealing ring (42) is located on the side of the second air chamber (46) away from the first air chamber (45) to seal the second air chamber (46).

4. A pneumatic needleless injector according to claim 1, characterized in that: The liquid circuit assembly also includes a three-way valve (34), the first interface of which is connected to the first check valve (4), the second interface of which is connected to the second check valve (35), and the third interface of which is connected to the liquid interface of the liquid pump column (33).

5. A pneumatic needleless injector according to claim 1, characterized in that: The source of the drug solution is a disposable syringe (1), which is connected to the first one-way valve (4) through a hose (3); an elastic syringe clamp (2) is fixed on the outer shell (12), and the disposable syringe (1) is clamped in the syringe clamp (2) and fixed to the outer shell (12) by screws.

6. A pneumatic needleless injector according to claim 1, characterized in that: The liquid pump column (33) is also provided with a nylon sleeve (29), a support ring (30) and a Y-shaped sealing ring (31). The nylon sleeve (29) and the support ring (30) are sleeved on the outer periphery of the firing pin (16). The Y-shaped sealing ring (31) is located between the firing pin (16) and the liquid pump column (33). The rear end of the liquid pump column (33) is equipped with a liquid pump end cap (28).

7. A pneumatic needleless injector according to claim 1, characterized in that: The tail end of the outer shell (12) is provided with a liquid volume adjustment module. The liquid volume adjustment module includes an end cap (13), a buffer pad (39) and a first sealing ring (38). The end cap (13) is fixedly connected to the tail end of the outer shell (12) by threads. The buffer pad (39) is disposed on the inner end face of the end cap (13). The first sealing ring (38) is disposed between the end cap (13) and the outer shell (12).

8. A pneumatic needleless injector according to claim 1, characterized in that: It also includes a mechanism to prevent accidental touch, which includes: The guide seat (43) is fixed to the housing (12), and the anti-accidental touch switch (8) is installed at the first end of the guide seat (43); The anti-accidental contact rod (7) is slidably installed at the second end of the guide seat (43), and the first end of the anti-accidental contact rod (7) is opposite to the anti-accidental contact switch (8); The sliding seat (6) is slidably sleeved on the outer surface of the liquid pump column (33), and the sliding seat (6) is fixed to the second end of the anti-accidental contact rod (7); Anti-slip sleeve (5), the sliding sleeve is located outside the jet nozzle (37) and is connected to the sliding seat (6); The spring (44) is slidably sleeved on the outer surface of the liquid pump column (33), with its front end fixed to the tail of the sliding seat (6) and its rear end fixed to the stepped end face provided on the outer cylindrical surface of the liquid pump column (33).

9. A pneumatic needleless injector according to claim 1, characterized in that: The air supply port of the pilot-operated two-position five-way solenoid valve (22) is connected to the gas storage cylinder (26) through the pressure regulating valve (25) and the pressure reducing bottle (24); the pilot-operated two-position five-way solenoid valve (22) is fixed to the gas storage cylinder (26) through the solenoid valve fixing clamp (23); the first air pipe (19) and the second air pipe (20) are connected to the pilot-operated two-position five-way solenoid valve (22) after being collected and tightened by the air pipe sleeve (21).

10. A pneumatic needleless injector according to claim 1, characterized in that: The first air chamber (45) is connected to the first air tube (19) through the first quick connector (17), and the second air chamber (46) is connected to the second air tube (20) through the second quick connector (18).

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