JP3120922B2 - Chemical injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drug solution injection device for injecting a predetermined amount of a drug solution into a body, and more particularly to a drug solution stored under pressure in a balloon to a patient at a constant speed. The present invention relates to a drug solution injector that can be injected.

[0002]

2. Description of the Related Art Conventionally, as a means for gradually injecting a drug solution such as an antibiotic, an anticancer drug, an anesthetic into a blood vessel, a bladder or the like, a drug solution is housed in a balloon made of an elastic material and the contraction force of the balloon is used. For continuously injecting drug solution into the human body
4-67873) is known. FIGS. 8 and 9 show the drug solution injector described in the publication. FIG. 8 is an overall explanatory view of the drug solution injection device, showing a state in which the puncture needle has not punctured the stopper of the housing, and FIG. 9 shows a state in which the drug solution is filled in the balloon of the housing shown in FIG. It is an expanded sectional view showing a state. 8 and 9 has a balloon portion e including a housing 43 that houses a balloon 42.
And a chemical solution outlet f having a flow rate control unit 44 for adjusting the flow rate of the chemical solution. The balloon 42 has a rod-shaped inner shaft 45 shown in FIG. 9, a cylindrical outer shaft 46 slidably mounted on the inner shaft 45, and one end of the inner shaft 45 on which the outer shaft 46 is mounted. An inner bearing 47 formed integrally with the inner shaft at the opposite end, and provided outside the two shafts so as to cover the inner shaft 45 and the outer shaft 46, one end of which is tightly fixed to the inner shaft 45. The other end is made of an elastic material balloon 42 that is tightly fixed to the outer shaft 46. At one end of the housing 43, an adapter 48 which is a chemical liquid inlet / outlet is formed. At the end of the drug solution passage 51, a stopper 49 is installed, and when the drug solution flows into the balloon 42, the drug solution is injected with a syringe needle, and when the drug solution flows out of the balloon 42, the injection needle 50 of FIG. By doing so, the liquid medicine is configured to be injected into the human body from a puncture needle (not shown) provided in the connector 52 at the end of the liquid medicine outlet f.

[0003]

In such a liquid injector, the inner shaft and the outer shaft are provided inside the balloon so that the balloon can be discharged at a constant pressure without causing significant deformation of the balloon. So that it deforms along the central axis in the long axis direction,
Further, by providing an inner bearing at the end inside the balloon, the balloon is configured to be deformed along the inner wall of the housing. However, such a drug solution injecting device is
The provision of such a mechanism in the interior of the device limits the downsizing of the drug solution injector naturally, and presents a problem when the patient injects the drug solution while carrying the device. The inventor of the present invention has made intensive studies to solve such a problem, and as a result, it has been found that the conventional method of injecting a drug solution into a human body only by the contraction force of a balloon filled with the drug solution,
Further, the present inventors have found that a chemical solution can be injected into a human body by a simple mechanism by further applying gas pressure, and have reached the present invention.

[0004]

That is, according to the present invention, a medicinal solution is stored in a pressurized state, and a balloon for inflow and outflow of the medicinal solution from an opening portion, the balloon is housed, and the outside of the balloon is filled with the medicinal solution. A housing composed of a gas chamber filled with a gas pressurized at a pressure higher than the pressure of the balloon, and a chemical inflow portion and / or a chemical solution outflow secured to an opening of the balloon provided on a wall forming the housing. Device, a gas injection port, a drug solution flow tube extending from the drug solution outflow portion, and a drug solution injection device comprising a flow rate control portion for controlling the amount of the drug solution arranged in the drug solution flow tube.
A fixed quantity valve is provided upstream of the chemical solution of the flow control unit.
It is a drug solution injection device that is made. Further, the present invention is the above-mentioned drug solution injector, wherein the balloon material is made of elastic rubber or thermoplastic resin.

Further, according to the present invention, in the liquid injector, the metering valve may be an orifice body made of a rubber-like elastic body having a valve hole whose inner diameter is deformable, and an adjusting means for adjusting the inner diameter of the valve hole. This is a drug solution injection device comprising: Further, in the present invention is the liquid injection device, the volume occupied by the gas chamber in the housing, at least <br/> Kutomo 0.2 times the volume occupied by the balloon when is filled with chemical solution amount of liquid medicine to be injected into the human body This is a certain drug injection device. Further, the present invention provides the drug solution injection device, wherein the flow control unit has an inner diameter of 10 to
This is a drug solution injection device consisting of a pipe with a fine inner diameter of 500μ. Still further, the present invention is the chemical injection device, wherein the inner diameter of the valve hole of the orifice body of the metering valve gradually increases from the minimum position on the upstream side of the chemical to the downstream side of the chemical. Also, the present invention provides the liquid medicine injection device, wherein the adjusting means for adjusting the inner diameter of the valve hole of the metering valve.
Is a screw portion formed on the inner wall of the cylindrical body on which the orifice body is disposed, on the upstream side of the chemical solution, and a screw portion formed on the outer wall of the plug body having a chemical solution upstream passage for communicating with the valve hole inlet. Is a screwed-in liquid injector.

[0006]

According to the present invention, a balloon is filled with a chemical solution and compressed from the outside of the balloon with a gas pressure greater than the contraction force of the balloon, thereby compressing the balloon. The medicinal solution is injected into the patient via the medicinal solution distribution tube. Bal
The rate of infusion of the drug solution into the patient is controlled by a flow rate control unit installed in the drug solution flow tube.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory view of an embodiment of a drug solution injection device according to the present invention, FIG. 2 is an enlarged sectional view of a balloon portion when a balloon is filled with a drug solution, and FIG. 3 is a drug solution shown in FIG. FIG. 4 is an enlarged sectional view of a connector of a distribution tube and a luer taper adapter. FIG. 4 shows a luer taper of the connector shown in FIG.
FIG. 5 is an explanatory view showing a state when inserted into a shape adapter.
FIG. 6 is an explanatory view showing a state in which the syringe is not connected to the balloon portion when the chemical solution in the syringe is caused to flow into the balloon. FIG. 6 is a diagram showing a state in which the chemical solution is injected into the balloon from the syringe shown in FIG. FIG. 7 is an explanatory view showing the vicinity of a flow rate control section in which a fixed quantity valve is disposed in a tube upstream of a chemical solution of the flow rate control section, and FIG. 8 is described in JP-A-4-67873. FIG. 9 is an enlarged cross-sectional view showing a state where the balloon of the housing shown in FIG. 8 is filled with a chemical solution.

In the figure, a is a balloon portion, b is a drug solution flowing tube portion, 1 and 42 are balloons, 2 and 43 are housings,
3 is a gas injection part, 4 is a chemical liquid inflow / outlet part, 5 and 44 are flow rate control parts, 6 is a connector part, 7 is a tube, 8 and 52 are fittings, 9 is a gas chamber, 10 is a metering valve, and 11 is a lock adapter. , 12 is a communication pipe, 14 is a check valve, 30 is an orifice body,
31 is a valve hole, 32 is a cylindrical body, 33 is a plug, 34 is a female screw part, 35
Indicates a male screw portion, 36 indicates a cap body, and 37 indicates a filter.

In FIG. 1, the chemical liquid injection device comprises a balloon portion a and a chemical liquid distribution tube b. Bal
As shown in FIG. 2, the valve portion a comprises a balloon 1 in which a chemical solution is accommodated in a housing 2 and a gas chamber 9 filled with a gas having a pressure greater than the contraction force of the balloon. Is a drive part for moving the to the injection point of the human body. The balloon 1 has a cylindrical or spherical shape with its one end closed and one end closed in a liquid-tight manner with the chemical solution inflow / outflow portion 4, and expands when a chemical solution is filled from the connector portion 6.
The cylindrical balloon has a structure capable of expanding in the longitudinal direction as well as in the radial direction. The balloon 1 can be of various sizes and thicknesses depending on the amount of the drug solution injected into the patient, the injection time, and the like, and is not particularly limited in the present invention.

The material of the balloon 1 includes an elastic rubber or a thermoplastic resin. Silicone as elastic rubber
Rubber, butyl rubber, acrylonitrile butadiene rubber, butadiene rubber, isoprene rubber, urethane rubber,
Elastic polymers or natural rubbers such as styrene-butadiene rubber, perprene, and Clayton rubber, or mixtures of these polymers, or processed substances containing antioxidants that are harmless to the human body after removing additives of these substances, or laminating −
And the like. Examples of the thermoplastic resin include unstretched, uniaxially stretched and biaxially stretched films of polyethylene, polypropylene, polyvinyl chloride, polyester, polyamide and the like.

The mouth of the balloon 1 is fixed in a liquid-tight manner by an O-ring 17 and a chemical liquid inflow / outflow part 4 fixedly formed on a wall of the housing 2 and a chemical liquid distribution tube b via a connector part 6. It has come to communicate with. A gas injection unit 3 for injecting a pressure gas is provided at an appropriate position on a wall of the housing 2. For example, butyl rubber or the like is used to prevent the pressure gas filled in the housing 2 from escaping to the outside. Gas barrier rubber stopper is installed. That is, the pressure gas is injected into the housing 2 by piercing the puncture needle into the rubber stopper, the puncture needle is punctured from the rubber stopper, and the pressure gas is held in the housing by the rubber stopper. It becomes the driving force for injecting the liquid medicine in the human body.
As the gas, air or an inert gas such as nitrogen gas is used.

The volume occupied by the gas chamber 9 in the housing 2 is at least 0.2 times, preferably , at least 0.2 times the volume occupied by the balloon 1 when the amount of the medicinal solution to be injected into the human body is filled.
It is 0.5 to 1.0 times. When the volume occupied by the gas chamber 9 is less than 0.2 times the volume occupied by the balloon 1, there is a tendency that the pressure of the gas chamber for injecting sustained the drug solution to the human body is too high. The pressure of the gas chamber varies depending on the balloon material, the amount of the drug solution in the balloon, and the like, but is usually 60 mmHg or more, preferably
It is 100-1500mmHg. In addition, the housing 2 prevents the balloon 1 from being damaged by touching an external sharp object, and does not scatter the chemical solution to the outside when a leak occurs from the balloon 1 due to a defect such as a pinhole of the balloon itself. In this way, it also has a function of sealing the chemical solution.

One end surface of the housing 2 is closed by a cap 13, and a central portion of the cap 13 is used to allow a chemical solution to flow into the balloon 1 or to allow the chemical solution to flow out of the balloon 1 to a predetermined location. A chemical liquid passage serving as a flow path is formed. As shown in FIGS. 3 to 6, a duckbill-type check valve 14, a fixed disk 15, and a sealing means 16 are provided in the chemical liquid passage from the balloon 1 side. The duck-bill type check valve 14 has a closed end of a valve-like shape of a platypus beak, which allows the drug solution to flow into the inside of the balloon 1 but prevents the flow in the reverse direction. . As the check valve 14, besides the duckbill type valve, an umbrella valve, a flap valve, a poppet valve, a ball valve, and the like can be used.
Examples include nylon, polyolefin, polyvinyl chloride, polycarbonate, and silicone resin. The fixed disk 15 supports the substrate of the check valve 14, and has an opening formed at the center thereof for outflow and inflow of the chemical solution.
The opening also serves as a drug solution outlet and a drug solution inlet.
1 to 4 is performed by opening the check valve 14 with the communication pipe 12 as shown in FIG. 4, but in the chemical injection device as shown in FIG. 8 and FIG. The medical solution in the balloon 1 is inserted into the stopper 49 by puncturing the injection needle 50 at the end of the medical solution flow tube portion f.

In FIG. 3, an O-ring serving as a sealing means 16 is disposed in an annular recess 18 formed by a lock adapter 11 as a connecting tool and a fixed disk 15.
The inner diameter of the O-ring is equal to or smaller than the outer diameter of the communication pipe, so that the sealing performance when the communication pipe 12 is inserted into the chemical solution passage is improved. The lock adapter 11 is a substantially cylindrical connection tool having an inner surface formed in a luer taper shape. The lock adapter 11 is fitted in a recess formed in the cap 13 of the housing 2. On the outer periphery of the end portion of the lock adapter 11, a projection 19 for connecting the chemical solution distribution tube b is formed. As shown in FIGS. 5 and 6, the flow of the drug solution into the balloon 1 is set in the syringe 21 of the syringe in the drug solution passage.
And the outer periphery of the needle base 22 of the syringe 21 is fitted on the inner surface of the lock adapter 11 in the form of a luer taper, and the projection 19 formed on the lock adapter 11 and the syringe 21 are inserted. This is performed by screwing with the screw portion 23. In FIG. 6, the needle base 22 of the syringe 21 is formed so as to screw with the lock adapter 11, but the outer circumference of the needle base 22 of the syringe 21 is fixed to the inner circumference of the lock adapter 11 in the form of a luer taper. The chemical solution may flow into the balloon while being pressed against the surface. At this time, the needle base 22 is located on the inlet side of the check valve 14 and its length is in a range not reaching the check valve 14, and the chemical solution flows into the balun when the chemical solution is filled.
To prevent backflow to the b side.

In FIG. 1, a chemical solution flow tube portion b includes a connector portion 6 connected to the lock adapter 11 of the chemical solution inflow / outflow portion 4, a flow rate control portion 5 for controlling the amount of the chemical solution, and a chemical solution outflow tube. And a connector 8. At one end of the connector portion 6, as shown in FIG. 3, a communication pipe 12 having a length capable of pressing and opening the check valve 14 and communicating with the interior of the balloon 1 when connected to the lock adapter 11 is provided. Is provided. This communication pipe 12 is made of polycarbonate,
It can be made of a synthetic resin such as polyvinyl chloride or polyolefin or a metal such as stainless steel. Communication pipe
Reference numeral 12 is fixed to the inner peripheral surface of the connector portion 6. As shown in FIG. 4, the length of the projecting portion of the communication pipe 12 is set to such a length that the duckbill check valve 14 can be expanded when the connector portion 6 and the lock adapter 11 are connected. ing. As a result, the check effect of the check valve 14 is forcibly released, and the chemical solution filled in the balloon 1 can be flowed out without using an injection needle. Thread on connector side
Reference numeral 20 denotes a connection between the balloon portion a and the chemical liquid distribution tube b by screwing with a projection 19 formed on the lock adapter 11. This connection may be made by fitting other than screwing.

FIG. 7 is an explanatory view of the vicinity of the flow control unit 5 in which the metering valve 10 is disposed in the tube on the chemical solution upstream side of the flow control unit 5. The flow control unit 5 is a part that controls the flow rate of the chemical solution,
For example, when a pipe having a fine inner diameter of 10 to 500 μm as shown in FIG. 7 is installed, the outflow speed of the chemical solution in the balloon 1 becomes slow, and the time for injecting the chemical solution into the human body can be lengthened. The length of the pipe is 1 cm or more, and the outer diameter is 5 to 500 times the inner diameter. When the length of the pipe exceeds 30mm,
It is preferable to use a case 26 accommodating a fine inner diameter pipe 25 having a crimped structure as shown in FIG. The flow rate control unit 5 is disclosed in Japanese Patent Application Laid-Open No. 2-11160 or 3-14
[0163] Metal pipes, synthetic resin pipes, glass pipes, and the like described in JP-A-163163 can be used.

A fixed quantity valve 10 is provided at the inlet of the chemical liquid upstream side of the flow control unit 5.
Is provided, the amount of the chemical liquid flowing into the flow control unit 5 can be made substantially constant, so that the flow rate can be controlled more accurately and the gas amount in the gas chamber 9 can be maintained for a long time. The metering valve 10 shown in FIG. 7 is an example.
A chemical solution tube 38, 39, a chemical solution passage 40,
It has a structure where 41 are arranged. The orifice body 30 has a valve hole 31 communicating from the chemical solution upstream side to the chemical solution downstream side.
Has a shape in which the inside diameter is minimized on the way from the valve hole inlet, and gradually increases from the minimum position toward the downstream side of the chemical solution. The inner diameter of the valve hole 31 can be arbitrarily changed depending on a desired chemical outflow speed. The orifice body 30 is fixed to the inner wall of the cylindrical body 32. A female screw portion 34 is formed on the inner wall of the cylindrical body 32 on the side of the chemical liquid inflow, and is screwed with a male screw portion 35 of the plug 33, and the orifice body is formed by rotating the plug 33.
30 is pressed to adjust the inner diameter of the valve hole 31. Between the valve hole 31 and the chemical solution upstream tube c, a filter 37 for removing minute substances contained in the chemical solution in the balloon 1 may be provided. The filter 37 is a tube on the chemical solution upstream side.
It is preferably installed at the tip of the bush c, and a fibrous material, a sintered material, or the like is used.

The stopper 33 has a chemical solution upstream passage 40 for communicating with the inlet of the valve hole 31 of the orifice body 30, and a chemical solution upstream passage.
A chemical solution upstream tube c connected to 40 is mounted,
The tip of the plug 33 is in contact with the orifice body 30, and the outlet of the chemical liquid upstream passage 40 and the inlet of the valve hole 31 of the orifice body 30 are communicated coaxially. A male screw portion 35 that is screwed with the female screw portion 34 of the cylindrical body 32 is formed on the tip side surface portion of the plug 33, and the male screw portion 35 is turned into a female type by rotating the plug 33. By moving the screw portion 34, the size of the inner diameter of the valve hole 31 of the orifice body 30 is adjusted, and the outflow speed of the chemical solution is adjusted. Cap body
Reference numeral 36 denotes a chemical solution downstream passage 41 for communicating with the outlet of the valve hole 31 of the orifice body 30, and a chemical solution downstream tube d connected to the chemical solution downstream passage 41. One end of the cap body 36 is in contact with the orifice body 30 and is fitted into the inner cavity of the cylindrical body 32, and the inlet of the chemical solution downstream passage 41 and the valve hole 31 of the orifice body 30 are provided.
Communicates coaxially with the outlet.

In the metering valve 10 shown in FIG.
A valve hole 31 is formed at a substantially central portion of the valve body, and by rotating the plug body 33, the tip of the plug body 33 presses the annular foot of the orifice body 30 made of a rubber-like elastic body. The liquid outflow speed is set slightly. The valve hole 31 has such a shape that the inside diameter becomes minimum while entering from the valve hole entrance, and gradually increases from the minimum position toward the downstream side of the chemical solution. In this state, the chemical supplied from the chemical upstream tube c through the chemical upstream passage 40 reaches the inlet of the valve hole 31 through the concave space formed at the inlet of the orifice body 31 and is given to the inlet. The minimum position of the inner diameter of the valve hole 31 is slightly changed by the pressure. As a result, the pressure of the drug solution flowing out of the outlet of the valve hole 31 is always kept substantially constant.

The orifice body 30 is made of a deformable rubber-like elastic body. Examples of the rubber-like elastic material include synthetic rubbers such as styrene / butadiene rubber, isoprene rubber, acrylonitrile / butadiene rubber, butadiene rubber, olefin rubber, fluorine rubber, silicone rubber, urethane rubber, clayton rubber, perprene, and natural rubber. And the like. The hardness of the elastic body is a hardness measured by a JIS-A type spring hardness tester of 25 to 70 degrees, preferably 35 to 60 degrees.
Degrees. If the hardness is less than 25 degrees, the orifice body 30 tends to be easily deformed due to the pressure of the chemical solution, it is difficult to adjust the inner diameter of the valve hole 31, and if the hardness exceeds 70 degrees, there is a slight chemical outflow pressure. The orifice body 30 does not respond to the change of the diameter, and the inner diameter of the valve hole 31 does not change. Valve hole 31
Can be arbitrarily changed depending on the desired chemical outflow rate, but usually 100 to 1000 μm is preferable.

In the chemical liquid distribution tube b shown in FIG. 1, the flow rate control unit 5 is installed at a position away from the connector 8. The chemical liquid downstream tube d from the flow control unit 5 to the connector 8 located downstream thereof has a chemical liquid upstream tube whose inner diameter extends from the flow control unit 5 toward the chemical liquid outflow unit located upstream thereof.
It is smaller than the inner diameter of the bush c. The inside diameter of the chemical solution downstream tube d is 15% to 85% of the inside diameter of the chemical solution upstream tube c.
%, Preferably 30% to 70%. The ratio of the inner diameter of the chemical solution upstream tube c to the chemical solution downstream tube d also varies depending on the length of the chemical solution downstream tube d. Chemical solution downstream tube
The length of the boss d is preferably at least 30 cm without being affected by the temperature of the arm.

The chemical distribution tube b is made of soft polyvinyl chloride, polypropylene, polyester, or the like, and a luer-taper-shaped connecting device 8 is provided at the other end. A PSV set or the like is connected.
The connector 8 may be provided with a check valve (not shown) for preventing the chemical solution from flowing backward due to venous pressure or the like. Note that the drug solution injection device of the present invention is disclosed in Japanese Patent Publication No. 3-55142,
JP-A-1-501451, JP-A-2-11160, JP-A-Hei.
It can also be used for a drug solution injector described in 3-170163 and the like.

[0024]

The chemical injection device of the present invention fills a balloon with a chemical solution and compresses the balloon from the outside of the balloon with a gas pressure greater than the contraction force of the balloon. The mechanism for injecting the liquid medicine in the balloon into the patient allows the operation mechanism of the balloon in the housing to be simpler than that of the conventional liquid injector, thereby injecting the liquid into the patient. Can be lowered. Also, by installing a metering valve at the upstream side of the chemical solution of the flow control unit, the amount of the chemical solution flowing into the flow control unit can be made substantially constant, and the amount of the chemical solution can be controlled more accurately, and the gas chamber can be controlled. The gas amount can be maintained for a long time, and the drug solution can be injected into the patient for a long time.

[Brief description of the drawings]

FIG. 1 is an explanatory view of one embodiment of a drug solution injector according to the present invention.

FIG. 2 is a perspective view of a balloon when a chemical solution is filled in the balloon of FIG. 1;
FIG.

FIG. 3 is an enlarged sectional view of a connector and a luer taper adapter of the chemical liquid distribution tube shown in FIG. 1;

FIG. 4 is an explanatory view showing a state when the connector shown in FIG. 3 is inserted into a luer-tapered adapter.

FIG. 5 is an explanatory view when injecting the drug solution in the syringe into the balloon, and is an explanatory view showing a state where the syringe and the balloon section are not connected.

FIG. 6 is an explanatory view when a chemical is filled into the balloon from the syringe shown in FIG. 5;

FIG. 7 is an explanatory view showing the vicinity of a flow rate control unit in which a metering valve is arranged in a tube on a chemical solution upstream side of the flow rate control unit.

FIG. 8 is an overall explanatory view of a drug solution injector described in Japanese Patent Application Laid-Open No. 4-67873.

FIG. 9 is an enlarged cross-sectional view showing a state where the balloon of the housing shown in FIG. 8 is filled with a chemical solution.

[Explanation of symbols]

 a balloon section b chemical liquid circulation tube section 1 balloon 2 housing 3 gas injection section 4 chemical liquid inflow / outflow section 5 flow rate control section 6 connector section 7 tube 8 connector 9 gas chamber 10 metering valve 11 lock adapter − 12 Communication pipe 14 Check valve 30 Orifice body 31 Valve hole 32 Cylindrical body 33 Plug body 34 Female screw part 35 Male screw part 36 Cap body 37 Filter

Claims (7)

(57) [Claims] 1. A balloon for storing a medicinal solution in a pressurized state and for allowing the medicinal solution to flow in and out of an opening, and a balloon containing the balloon, wherein the outside of the balloon is pressurized at a pressure higher than the pressure of the balloon filled with the medicinal solution. A gas chamber filled with the filled gas, a chemical liquid inlet and / or a chemical liquid outlet to which an opening of the balloon provided on a wall forming the housing is fixed, and a gas inlet, A drug solution injection device comprising: a drug solution flow tube extending from an outflow portion; and a flow rate control portion for controlling the amount of the drug solution arranged in the drug solution flow tube.
A chemical injection device provided with a metering valve on the outflow side . 2. The liquid injector according to claim 1 , wherein the balloon material is made of an elastic rubber or a thermoplastic resin. Wherein said shutoff valve includes an orifice body made of a rubber-like elastic material having an inner diameter of deformable valve hole, and a adjusting means for adjusting the inner diameter of the valve hole, according to claim 1, wherein Drug injection device. Volume 4. A occupied by the gas chamber in the housing is at least 0.2 times the volume occupied by the balloon when is filled with chemical solution amount of liquid medicine to be injected into the human body,
The drug solution injector according to any one of claims 1 to 3 . Wherein said flow controller is composed of a pipe of the fine inner diameter of the inner diameter of 10 to 500, the drug solution injector according to any one of claims 1-4. 6. An inner diameter of a valve hole of an orifice body of the metering valve.
It is gradually increased toward the liquid chemical downstream from the minimum position of the chemical liquid upstream, liquid injection device according to claim 3, wherein. Adjusting means for adjusting the inner diameter of 7. The valve hole of the shutoff valve includes a threaded portion formed in the chemical upstream of the inner wall of the orifice member is disposed a cylindrical body, and the valve hole inlet The drug solution injection device according to claim 3 , wherein a screw portion formed on an outer wall of the plug having a drug solution upstream side passage for communication is screwed.