CN217286168U

CN217286168U - Experiment bench for pneumatic needleless injector

Info

Publication number: CN217286168U
Application number: CN202122245910.4U
Authority: CN
Inventors: 姜克建; 刘仪
Original assignee: Zhejiang Sci Tech University ZSTU
Current assignee: Zhejiang Sci Tech University ZSTU
Priority date: 2021-09-16
Filing date: 2021-09-16
Publication date: 2022-08-26
Anticipated expiration: 2031-09-16

Abstract

The utility model discloses a pneumatic needleless injector experiment bench. Comprises an injector, a rack component for supporting the injector, and a gas source component for providing high-pressure gas and relieving pressure in the pipe; the injector is vertically fixed on the rack assembly and comprises a dosage adjusting assembly, an injection piston assembly and a needle cylinder assembly, wherein the dosage adjusting assembly is used for adjusting the dosage of the injected liquid medicine, the injection piston assembly is used for pushing the injected liquid medicine, and the needle cylinder assembly is used for introducing and containing the injected liquid medicine; the gas source assembly is arranged at the top of the dosage adjusting assembly through the quick connector, the gas introduced by the gas source assembly pushes the injection piston assembly to move downwards through the dosage adjusting assembly, and the injection piston assembly pushes the liquid medicine in the syringe assembly. The needleless injector of the utility model has the advantages of simple structure, low requirement on manufacturing process, convenient operation, low cost, dosage adjustment, wide application range, high injection efficiency and strong reliability.

Description

Experiment bench for pneumatic needleless injector

Technical Field

The utility model belongs to the field of medical equipment, concretely relates to pneumatic needleless injector experiment rack.

Background

Needleless injection of liquids is a mode of administration in which a drug is propelled by a motive force to produce a high-velocity jet into the subcutaneous tissue. A standard needleless injector is generally composed of two parts: a chamber to be fired (ampoule) for inhalation of the drug and temporary storage, a motive means for generating a pushing force. The power means typically consists of a power source, a trigger, a dose adjuster. The power source is typically a spring, a voice coil motor or compressed gas.

Needleless injection for animal epidemic prevention can produce many beneficial effects: 1. the biological safety is improved, the traditional needle-free injection is a mode of injecting the medicine into the subcutaneous part through a stainless steel needle head, the injection mode easily causes the conditions of injury, bleeding, swelling and the like to the skin, obvious pain is generated, even the danger of needle breakage is possibly generated, and the hidden danger can be eliminated by the needle-free injection. 2. The injection efficiency is improved, the injection time is short, and the injection device is suitable for large-scale injection; the safety of the construction is improved, the injury of personnel caused by the stress reaction generated by animals during injection is reduced, and the probability of virus infection of human is greatly reduced. 3. Reduces the treatment of medical waste, purifies the environment and reduces the cost. Because the requirement of large-scale animal immunization injection on an injection system is not as strict as that of human injection, the animal injector is required to be used for multiple times, has quick response and can generate the effects of automatic medicine suction and continuous injection.

The existing pneumatic needleless injector on the market at present has the disadvantages of complex structure, high requirement on manufacturing and processing precision and high price, and limits the popularization of the needleless injector.

The product is manufactured at present, and runs normally to achieve the expected effect.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems in the background art, the utility model provides a pneumatic needleless injector experiment bench with simple structure and good manufacturing process. The dose of the sucked liquid medicine is regulated by the dose regulating mechanism, the gas source assembly charges compressed gas into the energy storage cavity of the needleless injector, and when the gas pressure in the energy storage cavity reaches a certain value, the injection piston assembly overcomes the attraction force between the magnets to impact forwards and complete the injection process. During the period, the distance between the magnet and the plunger rod is adjusted to adjust the threshold value of the air pressure of the collision so as to change the injection pressure of the equipment facing different injection targets.

The utility model adopts the following technical scheme:

comprises an injector, a rack component for supporting the injector, and a gas source component for providing high-pressure gas and relieving pressure in a pipe; the injector is vertically fixed on the rack assembly and comprises a dosage adjusting assembly, an injection piston assembly and a needle cylinder assembly, wherein the dosage adjusting assembly is used for adjusting the dosage of the injected liquid medicine, the injection piston assembly is used for pushing the injected liquid medicine, and the needle cylinder assembly is used for introducing and containing the injected liquid medicine; the gas source assembly is arranged at the top of the dosage adjusting assembly through the quick connector, the gas introduced by the gas source assembly pushes the injection piston assembly to move downwards through the dosage adjusting assembly, and the injection piston assembly pushes the liquid medicine in the syringe assembly;

the inner part of the injector shell is divided into an upper chamber and a lower chamber, the upper chamber is provided with a dosage adjusting component, and the lower chamber is provided with an injection piston component; the dose adjusting component comprises a differential thread cap, a differential threaded rod, a guide sealing block, an energy storage cavity, a differential threaded rod pressing piece, a neodymium iron boron magnet mounting seat and a neodymium iron boron magnet; the outer side surface of the top of the injector shell sleeve is sleeved with a differential thread cap through threads, the inner side surface of the top of the injector shell sleeve is internally connected with a guide sealing block through threads, and the energy storage cavity is arranged in an upper cavity of the injector shell sleeve; the top end of the differential threaded rod penetrates out of the top of the differential threaded cap and then is connected with the differential threaded rod pressing piece through a screw, and the bottom of the differential threaded rod penetrates out of the middle of the guide sealing block and then extends into the energy storage cavity from top to bottom and is connected with the energy storage cavity through a thread; the bottom of the energy storage cavity is internally connected with a neodymium iron boron magnet mounting seat through threads, and the neodymium iron boron magnet is bonded with the neodymium iron boron magnet mounting seat through welding glue;

the injection piston assembly comprises a piston rod, a plunger rod return spring, a plunger limiting spring, a plunger rod and a plunger limiting cap; the plunger rod is arranged in the lower cavity of the syringe shell, the bottom of the plunger rod is provided with an installation groove, a plunger limiting cap is sleeved on the outer side surface of the bottom of the plunger rod through threads, one end of the plunger rod penetrates out of the plunger limiting cap and then extends into the installation groove of the plunger rod, a plunger limiting spring positioned in the installation groove is arranged between the plunger rod and the plunger rod, and the other end of the plunger rod extends into an inner pipeline of the ampoule shell through the bottom of the syringe shell; a plunger rod return spring is arranged in the lower chamber, one end of the plunger rod return spring props against the plunger rod, and the other end of the plunger rod return spring is in contact with the bottom surface of the lower chamber;

the needle cylinder component comprises a liquid medicine bottle, a liquid medicine tube, a liquid medicine storage one-way valve, an injection nozzle, an injection one-way valve and an ampoule shell; the top of the ampoule shell is connected to an opening at the bottom of the injector shell through threads, the bottom of the ampoule shell is connected with an injection nozzle through an injection one-way valve, and the liquid medicine bottle is connected with a liquid medicine storage one-way valve arranged on the side surface of the ampoule shell through a liquid medicine tube.

The thread direction between the differential threaded rod and the energy storage cavity is opposite to the thread direction between the differential threaded cap and the injector housing sleeve.

One end of the differential threaded rod close to the differential threaded cap is an optical axis with higher finish, and a guide sealing block is sleeved on the differential threaded rod; the other end is threaded and is connected with the energy storage cavity through threads. The differential screw cap and the injector shell are matched by adopting positive screw threads, and the differential screw rod and the energy storage cavity are matched by adopting negative screw threads, so that differential connection can be generated, the stroke of the piston rod can be enlarged, and the whole length of the device can be obviously shortened.

The top end of the differential screw cap is provided with a secondary stepped hole with a large upper part and a small lower part, the upper part of the stepped hole is a round hole, and the lower part of the stepped hole is a square hole; the convex block at the top of the differential threaded rod is embedded in the square hole of the stepped hole of the differential threaded cap, and the convex block is in clearance fit with the square hole; the differential threaded rod pressing piece is embedded in a circular hole of the differential threaded cap stepped hole and is in clearance fit with the circular hole; the differential threaded rod pressing piece is fixedly connected with a convex block at the top of the differential threaded rod through a screw.

The differential threaded rod is not directly locked with the differential threaded cap, but is overlapped and locked through a differential threaded rod pressing piece. The design reduces the assembly and processing requirements of parts, and prevents the locking and clamping conditions in later application of the parts due to the reasons of perpendicularity, flatness and the like.

A regular hexagon through hole is formed in the middle of the neodymium iron boron magnet mounting seat, and through holes coaxial with the regular hexagon through hole are formed in the middle of the convex block at the top of the differential threaded rod and the middle of the differential threaded rod pressing piece; an inner hexagonal wrench is inserted to rotate the regular hexagonal through hole to drive the neodymium iron boron magnet mounting seat to rotate so as to adjust the relative position between the neodymium iron boron magnet and the plunger rod.

A vertical limiting groove is formed in the outer peripheral surface of the energy storage cavity, and a positioning bolt penetrates through a threaded hole formed in the side surface of the syringe shell and is arranged in the vertical limiting groove to prevent the energy storage cavity from rotating circumferentially;

the side surface of the injector shell is provided with a silencing hole communicated with the lower cavity, the silencing hole is provided with a silencer, and when the plunger rod impacts the piston rod, the original gas in the lower cavity is discharged along the silencing hole.

The rack subassembly includes that bottom plate, lower margin, medicine bottle support frame, hand slip table accept board, syringe support, hand slip table. The bottom of the bottom plate is provided with a foot margin for supporting the bottom plate through threads, and the hand sliding table and the medicine bottle supporting frame are fixed on the bottom plate through screws; the hand sliding table bearing plate is fixed on the hand sliding table and moves up and down along with the rotation of a hand wheel of the hand sliding table, the position of an injector support connected with the hand sliding table bearing plate is changed, and the injector support and an injector outer shell sleeve are mutually fixed through threads and move along with the up-and-down movement of the injector support; the liquid medicine bottle is fixed on the liquid medicine bottle supporting frame and is used for adjusting the liquid medicine bottle.

The gas source assembly comprises a high-pressure gas cylinder, a three-way joint, a hand slide valve and a quick joint; the lower end of the three-way joint is communicated with the inside of the differential threaded rod through the quick joint, the left end and the right end of the three-way joint are respectively connected to the high-pressure gas cylinder and the hand slide valve, the high-pressure gas cylinder provides a power source, and the hand slide valve is a pressure relief switch, so that after injection is completed, pressure relief is performed on residual high-pressure gas in the device.

The inner side of the guide sealing block is provided with a guide sealing block o-shaped ring for sealing with the outer wall of the differential threaded rod; the outer side surfaces of the upper end and the lower end of the energy storage cavity are provided with an energy storage cavity O-shaped ring used for sealing with the inner wall of the syringe shell sleeve; the outer peripheral surface of the plunger rod is provided with a plunger rod o-shaped ring used for sealing the inner wall of the syringe outer shell; and a piston o-shaped ring used for sealing the inner wall of the ampoule shell is arranged on the outer peripheral surface of the bottom of the piston rod.

The plunger rod is made of spring steel mutually adsorbed with the neodymium iron boron magnet.

The end part of the differential threaded rod matched with the guide sealing block is an optical axis, and the differential threaded rod can freely move axially and rotate circumferentially in the guide sealing block.

The plunger rod moves axially along the syringe housing under the action of the high-pressure gas in the energy storage cavity.

The piston rod is driven by the plunger rod to move axially along the pipeline in the ampoule shell.

The utility model has the advantages that:

1. the existing pneumatic needleless injectors are complex in structure, a gas circuit is designed more, high-precision machining needs to be carried out at a triggering part and in an energy storage triggering cavity, and the cost is high. The utility model discloses in, simplify the device structure, reduce the gas circuit design, fully consider the processing technology requirement, reduce the processing degree of difficulty, reduce the cost.

2. The existing pneumatic needleless injector mostly adopts a lead screw nut connection mode to adjust the dosage, and the whole device is large and heavy, so that the pneumatic needleless injector is not beneficial to practical application. The utility model discloses in, adopt differential screw thread mode can enlarge injection liquid medicine dosage scope, simple reliable, it is convenient to use.

3. The utility model discloses in, change the injection pressure of syringe through adjusting the distance between neodymium iron boron magnet and the plunger rod, can easily adjust the injection degree of depth when the injection object in the face of different types and age, range of application is wider.

Drawings

Fig. 1 is an axial view of the appearance of the present invention.

Fig. 2(a) is a cross-sectional view of the body of the needleless injector (before injection).

Fig. 2(b) is a cross-sectional view of the body of the needleless injector (after injection).

Fig. 3(a) is an exploded view of the top of the dose dial assembly.

Fig. 3(b) is an exploded view of the bottom of the dose dial assembly.

Fig. 3(c) is an external view of the ndfeb magnet mounting base.

Fig. 4(a) is a partial exploded view of the injection piston assembly.

Fig. 4(b) is a partial cross-sectional view of the plunger.

The figure shows that:

1. a rack assembly: bottom plate 11, lower margin 12, medicine bottle support frame 13, hand slip table socket board 14, syringe support 15, hand slip table 16.

2. Store up medicine syringe subassembly: a liquid medicine bottle 21, a liquid medicine tube 22, a liquid medicine storage one-way valve 23, an injection nozzle 24, an injection one-way valve 25 and an ampoule shell 26.

3. An injection piston assembly: piston rod 31, piston o-ring 32, plunger rod return spring 33, plunger limit spring 34, plunger rod 35, plunger limit cap 36, plunger rod o-ring 37.

4. A syringe housing cover 41, a silencer 42, and a set bolt 43.

5. A dose adjustment assembly: the device comprises a differential threaded cap 51, a differential threaded rod 52, a guide sealing block 53, a guide sealing block o-shaped ring 54, an energy storage cavity 55, an energy storage cavity o-shaped ring 56, a differential threaded rod pressing piece 57, a neodymium iron boron magnet mounting seat 58 and a neodymium iron boron magnet 59.

6. An air source assembly: a high-pressure gas cylinder 61, a high-pressure gas pipe 62, a three-way joint 63, a hand slide valve 64 and a quick joint 65.

Detailed Description

The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

In the following description of the directions, the directions are defined according to the directions observed in the drawings.

Fig. 1 is an appearance view of the syringe, which includes a bottom plate 11, a foot rest 12, a medicine bottle support frame 13, a hand sliding table bearing plate 14, a syringe support frame 15, a hand sliding table 16, a medicine bottle 21, a medicine tube 22, a medicine storage one-way valve 23, an injection nozzle 24, an injection one-way valve 25, an ampoule shell 26, a syringe shell sleeve 41, a differential screw cap 51, a high-pressure gas bottle 61, a high-pressure gas tube 62, a three-way joint 63, a hand sliding valve 64 and a quick joint 65. The ground feet 12 are fixed with the bottom plate 11 through threads, the medicine bottle support frame 13 is connected with the bottom plate through screws, and the medicine bottle support frame 13 is a vertically movable support and is convenient for adjusting the height of the medicine bottle 21. The liquid medicine bottle 21 is sleeved in the hole of the liquid medicine bottle support frame 13, and the liquid medicine flows into a medicine storage one-way valve 23 in the needleless injector along the medicine tube 22. The medicine storage one-way valve 23 is fixedly connected with the ampoule shell 26 through pipe threads, and air tightness is guaranteed. The injection one-way valve 25 is also connected with the ampoule shell 26 through pipe threads, and the injection nozzle 24 is connected with the other end of the injection one-way valve 25 (the aperture of the nozzle is less than 0.3 mm). The hand sliding table 16 and the bottom plate are fixedly connected with each other through screws, the hand sliding table bearing plate 14 is fixed on the hand sliding table 16 and moves up and down along with the rotation of a hand wheel of the hand sliding table 16 to change the position of the injector support 15, and the injector support 15 and the injector outer shell 41 are mutually fixed through threads and move along with the up and down movement of the injector support 15. The differential screw cap 51 is sleeved on the top of the syringe housing sleeve 41 through screw threads, the quick connector 65 is fixed with the dose adjusting assembly through screw threads, and the high-pressure air tube 62 is connected with the high-pressure air bottle 61 and the hand slide valve 64 through a three-way connector. The high pressure gas bottle 61 provides the power source, and the hand slide valve 64 acts as a pressure release switch to release the high pressure gas remaining in the device after the injection is completed.

Fig. 2(a) is a cross-sectional view of the body of the needleless injector, showing the state before injection of the needleless injector. The injection device comprises an injection nozzle 24, an injection one-way valve 25, an ampoule shell 26, a piston rod 31, a piston o-ring 32, a plunger rod return spring 33, a plunger limiting spring 34, a plunger rod 35, a plunger limiting cap 36, a plunger rod o-ring 37, an injector shell sleeve 41, a silencer 42, a positioning bolt 43, a differential thread cap 51, a differential thread rod 52, a guide sealing block 53, a guide sealing block o-ring 54, an energy storage cavity 55, an energy storage cavity o-ring 56, a differential thread rod pressing piece 57, a neodymium iron boron magnet mounting seat 58, a neodymium iron boron magnet 59, a high-pressure gas cylinder 61, a high-pressure gas pipe 62, a three-way joint 63, a hand sliding valve 64, a quick joint 65, a silencer 42, an injector shell 41, a positioning bolt 43, a liquid medicine bottle 21, a liquid medicine pipe 22 and a liquid medicine storage one-way valve 23. The high-pressure gas cylinder 61 on the right side of the figure supplies high-pressure gas, and the high-pressure gas cylinder 61 is provided with a switch which can freely control the release of the gas flow. The switch of the high-pressure gas bottle 61 is opened, high-pressure gas flows into the quick coupling 65 through the three-way joint 63 along the high-pressure gas pipe 62, the quick coupling 65 is fixed with the differential threaded rod 52 through threads, a through hole is formed in the center of the differential threaded rod, gas flow enters the energy storage cavity 55, the neodymium iron boron magnet mounting seat 58 is fixed at the bottom of the energy storage cavity 55 through threaded connection, and the neodymium iron boron magnet 59 is adhered to the neodymium iron boron magnet mounting seat 58 through welding glue. The plunger rod 35 is made of spring steel and mutually adsorbed with the neodymium iron boron magnet 59, and when the pressure of high-pressure gas entering the energy storage cavity 55 is larger than the attractive force between the neodymium iron boron magnet 59 and the plunger rod 35, the plunger rod 35 is forced to move forwards and moves rapidly towards the direction of the injection nozzle 24; the front part of the plunger rod 35 is connected with a plunger limiting cap 36 through threads, the front part of the plunger rod 35 is provided with a mounting groove, a plunger limiting spring 34 is positioned in the mounting groove of the plunger rod 35, one end of the plunger limiting spring is contacted with the bottom of the hole of the plunger rod 35, and the other end of the plunger limiting spring is contacted with the piston rod 31. When the plunger rod 35 impacts forwards, the plunger rod 35 firstly presses the plunger limiting spring 34 to deform the plunger limiting spring, when the running speed of the plunger limiting spring 34 is the same as that of the plunger rod 35, the plunger limiting spring and the plunger limiting spring impact the piston rod 31 together, a certain impact stroke is reserved through spring buffering, and energy utilization is maximized. A silencing hole is arranged at one end of the injector shell 41 close to the injection nozzle 24, a silencer 42 is arranged, and when the plunger rod 35 impacts the piston rod 31, original gas in the cavity is discharged along the silencing hole. One end of the piston rod 31 extends into the inner pipeline of the ampoule shell 26, the other end is positioned in the syringe shell 41 and can move along with the back and forth movement of the plunger rod 35, and the front end of the piston rod 31 is provided with a piston o-ring 32 which mainly prevents the liquid medicine from leaking or flowing backwards. When the piston rod 35 impacts the liquid medicine in the ampoule shell 26, the liquid medicine impacts the injection check valve 25, high-pressure jet flow is generated through the injection nozzle 24, and subcutaneous injection of the target animal is completed.

Fig. 2(b) is a cross-sectional view of the body of the needleless injector, showing the state after the injection of the needleless injector. The injection device comprises an injection nozzle 24, an injection one-way valve 25, an ampoule shell 26, a piston o-ring 32, a piston rod 31, a plunger rod return spring 33, a plunger limiting cap 36, a plunger limiting spring 34, a plunger rod 35, a plunger rod o-ring 37, a differential threaded cap 51, an energy storage cavity o-ring 56, an energy storage cavity 55, a guide sealing block 53, a guide sealing block o-ring 54, a differential threaded rod 52, a differential threaded rod pressing piece 57, a neodymium iron boron magnet mounting seat 58, a neodymium iron boron magnet 59, a high-pressure gas cylinder 61, a high-pressure gas pipe 62, a three-way joint 63, a hand sliding valve 64, a quick joint 65, a silencer 42, an injector shell 41, a positioning bolt 42, a liquid medicine bottle 21, a liquid medicine pipe 22 and a liquid medicine storage one-way valve 23. In the figure the plunger rod return spring 33 is in a compressed state, where the device is reset. The high pressure gas cylinder 61 is first closed and further input of high pressure gas is prohibited. The hand valve 64 is opened to release the pressure in the energy storage chamber 55. After the pressure relief step is completed, the plunger rod 35 moves towards the energy storage cavity 55 under the combined action of the plunger rod return spring 33 and the neodymium iron boron magnet 59, and is tightly attached to the energy storage cavity 55. The piston rod 31 is driven by the movement of the plunger rod 35 to move, negative pressure is generated in the ampoule shell 26, and the liquid medicine in the liquid medicine bottle 21 flows into the ampoule shell 26 through the medicine storage one-way valve 23 along the medicine tube 22 under the action of the atmospheric pressure to wait for the next injection action. At this time, if the adjustment of the dosage of the liquid medicine is to be performed, the differential screw cap 51 is rotated, the differential screw rod 52 is driven by the differential screw cap 51 to move axially along the syringe housing 41, so that the relative position of the energy storage cavity 55 in the chamber is changed, the medicine suction amount of the needleless syringe is adjusted, and the energy storage cavity 55 cannot rotate circumferentially due to the limiting effect of the mutual matching of the limiting groove and the positioning bolt 43. The guide sealing block 53 and the injector housing sleeve 41 are mutually fixed through threads, and the interior of the part is subjected to high finish treatment; one end of the differential threaded rod 52 close to the differential threaded cap 51 is an optical axis with high smoothness, the differential threaded rod is limited by the guide sealing block 53, the differential threaded rod can freely move axially and rotate circumferentially in the guide sealing block 53, an inner groove is machined on the inner side of the guide sealing block 53, and an o-shaped ring 54 of the guide sealing block is installed to ensure the air tightness of the device in the working process; the other end of the differential threaded rod 52 is threaded and is matched with the energy storage cavity 55, the differential threaded cap 51 is matched with the injector shell 41 by adopting positive threads, and the differential threaded rod 52 is matched with the energy storage cavity 55 by adopting negative threads, so that differential connection can be generated, the stroke of the piston rod 31 is obviously prolonged, the injection liquid medicine dosage is improved, and the whole length of the device can be obviously shortened. In order to prevent the energy storage cavity 55 from only rotating circumferentially but not moving axially back and forth when the differential threaded rod 52 is rotated due to surface friction, fit tolerance and the like in the adjustment process, the threaded hole is formed in the syringe housing sleeve 41, the positioning bolt 43 is inserted, and the limiting groove is formed in the energy storage cavity 55, so that the problem of follow-up rotation of the energy storage cavity 55 can be effectively prevented.

Fig. 3(a) is an exploded view of the rear end of the dose setting assembly, including the differential threaded cap 51, the differential threaded rod 52, the guide seal block 53, the differential threaded rod follower 57. The front end of the differential threaded rod 52 is a threaded part and is used for driving the energy storage cavity 55, and the rear end of the differential threaded rod is a high-finish optical axis and is matched with the guide sealing block 53; the head of the differential threaded rod 52 is milled with a convex block, is embedded in the square slotted hole of the differential threaded cap 51, is not directly locked with the differential threaded cap 51, and is overlapped and locked through the differential threaded rod pressing piece 57. The design reduces the assembly and processing requirements of parts, and prevents the locking and clamping conditions in later application of the parts due to the reasons of perpendicularity, flatness and the like.

Fig. 3(b) is an exploded view of the front end of the dose setting assembly, including set bolt 42, differential threaded rod 52, energy storage chamber 55, ndfeb magnet mount 58, ndfeb magnet 59. The differential threaded rod 52 is matched with the energy storage cavity 55 through front end threads, and the relative position of the energy storage cavity 55 is changed, so that the medicine suction quantity of the needleless injector is adjusted. Neodymium iron boron magnet 59 is bonded to neodymium iron boron magnet mounting base 58 through a welding glue, and neodymium iron boron magnet mounting base 58 is connected with the front end of energy storage cavity 55 through a thread. The differential screw cap 51 is provided with a hole to prevent the difficulty of rotation due to the airtight problem.

Fig. 3(c) is an external view of the ndfeb magnet mounting base 58. The ndfeb magnet mounting seat 58 is provided with a regular hexagon through hole M3, different injection pressures are needed for different injection targets of different types and ages, therefore, in combination with the graph (b) in fig. 2, the injection pressure of the needleless injection device can be changed by adjusting the relative distance between the ndfeb magnet 59 and the plunger rod 35, in the using process, the M5 quick joint 65 is pulled out, the hexagon socket wrench is inserted forward along the through hole of the differential threaded rod 52, the positioning bolt 43 is screwed down at the same time, the energy storage cavity 55 does not rotate circumferentially, the hexagon socket wrench is rotated to drive the ndfeb magnet mounting seat 58 to rotate, the relative position between the ndfeb magnet 59 and the plunger rod 35 is adjusted by a rotation angle to change the attraction force between the ndfeb magnet 59 and the plunger rod 35, and different injection pressures can be generated when different injection targets are met.

Fig. 4(a) is a partially exploded view of the injection piston assembly, and fig. 4(b) is a partially sectional view of the plunger, including the piston rod 31, the plunger limit spring 34, the plunger rod 35, and the plunger limit cap 36. The plunger rod 35 and the plunger limiting cap 36 are locked and fixed through threads, one end of the plunger limiting spring 34 abuts against the bottom of the mounting groove of the plunger rod 35, the other end of the plunger limiting spring abuts against the large head of the piston rod 31, the end part of the piston rod (31) penetrates out of the plunger limiting cap (36) and then extends into the mounting groove of the plunger rod (35), and due to the fact that a certain impact distance is reserved for buffering of the plunger limiting spring 34, the utilization of impact energy can be maximized.

Claims

1. A pneumatic needleless injector experiment bench is characterized by comprising an injector, a bench component for supporting the injector, and a gas source component for providing high-pressure gas and relieving pressure in a pipe; the injector is vertically fixed on the rack assembly and comprises a dosage adjusting assembly, an injection piston assembly and a needle cylinder assembly, wherein the dosage adjusting assembly is used for adjusting the dosage of the injected liquid medicine, the injection piston assembly is used for pushing the injected liquid medicine, and the needle cylinder assembly is used for introducing and containing the injected liquid medicine; the gas source assembly is arranged at the top of the dosage adjusting assembly through a quick connector (65), gas introduced by the gas source assembly pushes the injection piston assembly to move downwards through the dosage adjusting assembly, and the injection piston assembly pushes the liquid medicine in the needle cylinder assembly;

the interior of the injector shell sleeve (41) is divided into an upper chamber and a lower chamber, the upper chamber is provided with a dosage adjusting assembly, and the lower chamber is provided with an injection piston assembly;

the dose adjusting component comprises a differential thread cap (51), a differential threaded rod (52), a guide sealing block (53), an energy storage cavity (55), a differential threaded rod pressing piece (57), a neodymium iron boron magnet mounting seat (58) and a neodymium iron boron magnet (59); the outer side surface of the top of the syringe shell sleeve (41) is sleeved with a differential thread cap (51) through threads, the inner side surface of the top of the syringe shell sleeve (41) is internally connected with a guide sealing block (53) through threads, and an energy storage cavity (55) is arranged in an upper cavity of the syringe shell sleeve (41); the top end of the differential threaded rod (52) penetrates out of the top of the differential threaded cap (51) and then is connected with a differential threaded rod pressing piece (57) through a screw, and the bottom of the differential threaded rod (52) penetrates out of the middle of the guide sealing block (53) and then extends into the energy storage cavity (55) from top to bottom and is connected with the energy storage cavity (55) through a screw thread; the bottom of the energy storage cavity (55) is internally connected with a neodymium iron boron magnet mounting seat (58) through threads, and the neodymium iron boron magnet (59) is bonded with the neodymium iron boron magnet mounting seat (58) through welding glue;

the injection piston assembly comprises a piston rod (31), a plunger rod return spring (33), a plunger limiting spring (34), a plunger rod (35) and a plunger limiting cap (36); the plunger rod (35) is arranged in a lower cavity of the syringe casing sleeve (41), a mounting groove is formed in the bottom of the plunger rod (35), a plunger limiting cap (36) is sleeved on the outer side face of the bottom of the plunger rod (35) through threads, one end of the piston rod (31) penetrates out of the plunger limiting cap (36) and then extends into the mounting groove of the plunger rod (35), a plunger limiting spring (34) located in the mounting groove is arranged between the piston rod (31) and the plunger rod (35), and the other end of the piston rod (31) extends into an inner pipeline of the ampoule casing (26) through the bottom of the syringe casing sleeve (41); a plunger rod return spring (33) is arranged in the lower cavity, one end of the plunger rod return spring (33) is propped against the plunger rod (35), and the other end of the plunger rod return spring is contacted with the bottom surface of the lower cavity;

the syringe component comprises a liquid medicine bottle (21), a liquid medicine tube (22), a liquid medicine storage one-way valve (23), an injection nozzle (24), an injection one-way valve (25) and an ampoule shell (26); the top of the ampoule shell (26) is connected to the bottom opening of the injector shell sleeve (41) through threads, the bottom of the ampoule shell (26) is connected with the injection nozzle (24) through the injection one-way valve (25), and the liquid medicine bottle (21) is connected with the liquid medicine storage one-way valve (23) arranged on the side surface of the ampoule shell (26) through the liquid medicine tube (22).

2. A pneumatic needleless injector test stand according to claim 1, wherein the thread direction between the differential threaded rod (52) and the accumulator chamber (55) is opposite to the thread direction between the differential threaded cap (51) and the injector housing sleeve (41).

3. The pneumatic needleless injector experiment bench according to claim 1, wherein the top end of the differential threaded cap (51) is provided with a secondary stepped hole with a large upper part and a small lower part, the upper part of the stepped hole is a round hole, and the lower part of the stepped hole is a square hole; a convex block at the top of the differential threaded rod (52) is embedded in a square hole of a stepped hole of the differential threaded cap (51), and the convex block is in clearance fit with the square hole; the differential threaded rod pressing piece (57) is embedded in a round hole of a stepped hole of the differential threaded cap (51), and the differential threaded rod pressing piece (57) is in clearance fit with the round hole; the differential threaded rod pressing piece (57) is fixedly connected with a convex block at the top of the differential threaded rod (52) through a screw.

4. The experiment bench for the pneumatic needleless injector according to claim 1, wherein a regular hexagon through hole is formed in the middle of the neodymium iron boron magnet mounting seat (58), and a through hole coaxial with the regular hexagon through hole is formed in the middle of a convex block at the top of the differential threaded rod (52) and in the middle of the differential threaded rod pressing piece (57); an inner hexagonal wrench is inserted to rotate the regular hexagonal through hole to drive the neodymium iron boron magnet mounting seat (58) to rotate so as to adjust the relative position between the neodymium iron boron magnet (59) and the plunger rod (35).

5. The experiment bench for the pneumatic needleless injector according to claim 1, wherein a vertical limit groove is formed in the outer peripheral surface of the energy storage cavity (55), and the positioning bolt (43) passes through a threaded hole formed in the side surface of the injector outer shell (41) and is installed in the vertical limit groove to prevent the energy storage cavity (55) from rotating circumferentially;

a silencing hole communicated with the lower chamber is formed in the side face of the injector shell sleeve (41), and a silencer (42) is mounted on the silencing hole.

6. The pneumatic needleless injector experiment bench of claim 1, wherein the bench assembly comprises a bottom plate (11), a ground foot (12), a medicine bottle support frame (13), a hand slide bearing plate (14), an injector support frame (15) and a hand slide (16); the bottom of the bottom plate (11) is provided with a foundation (12) for supporting the bottom plate (11) through threads, and the hand sliding table (16) and the medicine bottle support frame (13) are fixed on the bottom plate (11) through screws; the hand sliding table bearing plate (14) is fixed on the hand sliding table (16), moves up and down along with the rotation of a hand wheel of the hand sliding table (16), changes the position of an injector bracket (15) connected with the hand sliding table bearing plate (14), and the injector bracket (15) and an injector outer shell sleeve (41) are mutually fixed through threads and move along with the up and down movement of the injector bracket (15); the medicine bottle (21) is fixed on the medicine bottle support frame (13) and is used for adjusting the working height of the medicine bottle (21).

7. A pneumatic needleless injector test stand according to claim 1, wherein said gas source assembly comprises a high pressure gas cylinder (61), a three way joint (63), a hand slide valve (64), a quick connector (65); the lower end of the three-way joint (63) is communicated with the inside of the differential threaded rod (52) through a quick joint (65), the left end and the right end of the three-way joint (63) are respectively connected to a high-pressure gas cylinder (61) and a hand slide valve (64), the high-pressure gas cylinder (61) provides a power source, and the hand slide valve (64) is a pressure relief switch.

8. A pneumatic needleless injector laboratory bench according to claim 1, wherein a guide seal block o-ring (54) for sealing with the outer wall of the differential threaded rod (52) is installed inside the guide seal block (53); the outer side surfaces of the upper end and the lower end of the energy storage cavity (55) are provided with energy storage cavity o-rings (56) which are used for sealing with the inner wall of the injector shell sleeve (41); a plunger rod o-shaped ring (37) used for sealing the inner wall of the syringe outer shell (41) is arranged on the outer peripheral surface of the plunger rod (35); a piston o-ring (32) for sealing with the inner wall of the ampoule shell (26) is arranged on the outer peripheral surface of the bottom of the piston rod (31).

9. A pneumatic needleless injector test stand according to claim 1, wherein the plunger rod (35) is made of spring steel with neodymium iron boron magnet (59) attached to it.

10. A pneumatic needleless injector laboratory bench according to claim 1, wherein the end of the differential threaded rod (52) engaged with the guide seal block (53) is an optical axis, and the differential threaded rod (52) is free to move axially and rotate circumferentially in the guide seal block (53).