JPH0861296A - Constant quantity dispenser - Google Patents

Abstract

PURPOSE: To keep a delivery quantity at each time at a constant value without applying complicated pressure control, in a constant quantity dispenser which is devised to intermittently deliver a solution in a syringe by periodically applying a positive and a negative pressure. CONSTITUTION: A syringe 12 having a solution deliver nozzle 11 forms a closed chamber and the syringe 12 is communicated with a solution tank 14 through a communication pipe 15 fronting on the interior of the syringe 12. A float valve 20 to open and close the inner opening part of the syringe 12 of the communication pipe 15 according to a solution level in the syringe 12 is located at the communication pipe 15. A periodic positive pressure by a control air feed means 30 is applied to the liquid surface of the closed syringe 12.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fixed amount dispenser for discharging a liquid agent such as an adhesive in fixed amounts.

[0002]

2. Description of the Related Art FIG. 13 shows the principle of a conventional metered dose dispenser of this type. The syringe 2 supplied with the liquid agent 1 filled therein is fitted with a slidable pressurizing piston 3 and an upper lid 5 forming a pressure chamber 4 between the pressurizing piston 3 and the pressurizing piston 3. The syringe 2 is attached to and detached from the jaw 6 on the control device side by the flange 2a. The jaw 6 and the upper lid 5 have an air passage 6a,
5a is formed, and the control pressure from the air pressure control device 7 is guided to the pressure chamber 4 via the conduit 8. The air pressure control device 7 alternately supplies a positive pressure and a negative pressure to the pressure chamber 4 in a constant cycle, and when the positive pressure is supplied, the liquid agent 1 in the syringe 2 is discharged from the discharge nozzle 2b. The negative pressure supply is for preventing unnecessary liquid dripping until the next positive pressure supply.

Since the air pressure control device 7 has a fixed amount of discharge,
A fixed amount of compressed air was supplied to the pressure chamber 4 for each positive pressure supply. However, since the pressurizing piston 3 descends and the volume of the pressure chamber 4 increases with the consumption of the liquid agent 1 in the syringe 2, once the liquid agent 1 is consumed, as shown by a broken line A in FIG. There is a problem that the discharge amount per hit is reduced. In order to solve this problem, conventionally, as the volume of the pressure chamber 4 increases (the amount of the liquid agent 1 decreases), the supply pressure by the air pressure control device 7 is increased (corrected) as shown by the solid line B, and the discharge amount is shown by the solid line C. As mentioned above, the control for keeping it constant has been performed. However, this control is performed by watching the volume change of the pressure chamber 4,
Since the supply pressure must be adjusted precisely in accordance with the result, the control system becomes complicated and expensive.

[0004]

OBJECT OF THE INVENTION It is an object of the present invention to obtain a metered amount dispenser which can maintain a constant discharge amount by a cheaper mechanical means.

[0005]

SUMMARY OF THE INVENTION The present invention has been completed based on the idea that the above problems of the conventional apparatus can be solved if the liquid level in the syringe is always kept constant. The syringe is set as a closed chamber, and this syringe is communicated with a liquid agent tank through a communication pipe facing the inside of the syringe, and the communication pipe is provided with an opening in the syringe of the communication pipe according to the liquid agent level in the syringe. A float valve that opens and closes is provided, and the periodic positive pressure by the control air supply means is
The feature is that it is applied to the liquid surface of the closed syringe.

According to this structure, since the liquid level in the syringe can be kept substantially constant, the amount of air in the syringe (volume other than the liquid agent) can also be kept substantially constant. The amount of liquid dropped from the nozzle each time the pressure is applied can be made substantially constant.

The float valve can be most simply composed of a lower end opening of the communicating pipe and a spherical float valve body which moves according to the liquid level to open and close the lower end opening. Alternatively, the float valve can be configured by the lower end opening of the communication pipe, the valve body that opens and closes the lower end opening, and the float that moves according to the liquid level and that is connected to the valve body.

In order to ensure the closing of the float valve, the valve body of the float valve is closed in the closing direction by a spring having a strength that does not prevent the float valve from opening when the liquid level falls below a predetermined level. Can be biased.

Further, in the metered dose dispenser of the present invention, when the viscosity of the liquid agent is high, the liquid agent tank can be closed and a constant pressure can be exerted on the liquid surface. Furthermore, in order to prevent the liquid agent on the syringe side from flowing into the control air supply means due to an accident, allow an air flow between the control air supply means and the syringe between the control air supply means and the syringe, It is preferable to provide a check valve for blocking the flow of the liquid agent from the side to the side of the control air supply means.

More specifically, in the structure around the float valve, the communication pipe is composed of a straight pipe which is oriented in the vertical direction in use, while the float valve is a float fitted slidably on the outer periphery of the straight pipe. Body and a valve body that is supported by the float body via spring means to open and close the lower end opening of the communication pipe, and the force of the spring means causes the float body to move to the normal floating position by the buoyancy of the liquid agent in the syringe. Preferably, the valve body is seated in the opening of the communication tube when positioned at.

The float body may be composed of, for example, an inner and outer double cylinder having an air chamber in the middle. Then, in order to prevent the liquid agent from overflowing into the syringe and further flowing to the control air supply means due to an accident, in this float body, when the liquid agent level in the syringe relative to the float body rises from the normal position, A liquid agent introducing hole is provided for guiding the liquid agent into the air chamber between the inner and outer double cylinders and sinking the float body into the liquid agent.When the float body sinks, the liquid agent introducing hole is provided in the opening of the communication pipe. It is preferable to provide a safety valve for blocking the liquid flow.

The safety valve is opened when a positive pressure acts on the liquid surface of the liquid agent in the syringe to allow the liquid agent in the syringe to flow toward the liquid agent tank side, and when a negative pressure acts on the liquid surface, the liquid agent tank. It is preferable to use a valve that blocks the flow of the liquid agent from the inside into the syringe. More specifically, the valve body and the safety valve of the float valve are provided with a cylindrical valve seat body having valve seats at the upper and lower ends at the lower end opening of the communication pipe. The valve seat of the safety valve and the valve body of the float valve are arranged to come into contact with and separate from the seat, and the valve body of the float valve pushes up the valve body of the safety valve when closing the lower end opening of the communication pipe. Is practical.

In a broader concept of the present invention, a closed syringe equipped with a nozzle for discharging a liquid agent; a liquid agent tank communicating with the syringe via a communication pipe facing the syringe; An on-off valve that opens and closes the opening in the syringe of the communication pipe; an on-off valve control mechanism that detects the liquid level in the syringe and controls the opening and closing of the on-off valve so that the liquid level becomes almost constant; It can be defined as a fixed amount dispenser provided with a control air supply means for periodically applying a positive pressure to the surface and discharging the liquid agent in the syringe from the nozzle each time the positive pressure is applied.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to illustrated embodiments. FIG. 1 shows a first embodiment of the present invention, in which a partition wall 13 is provided on a syringe 12 having a liquid agent discharge nozzle 11.
A liquid agent tank 14 partitioned by is provided. The liquid agent tank 14 and the syringe 12 are communicated with each other by a communication pipe 15 that faces the inside of the syringe 12 from the solution tank 14 through the partition wall 13. The communication pipe 15 is composed of a straight pipe that is oriented in the vertical direction when in use.

At the lower end of the communication pipe 15, the float valve 2
0 is provided. This float valve 20 is connected to the communication pipe 1
The lower end opening (valve seat) 15a of 5 is opened and closed by a float valve body 21 made of a sphere, and the float valve body 21 has a specific gravity so as to move following the level of the liquid surface 17a in the syringe 12. Composed of small materials. Communication pipe 15
A lower cup-shaped movement restricting member 22 that restricts the radial movement range of the communication pipe 15 of the float valve body 21 is provided. At the lower end portion of the movement restricting member 22, a mesh body or the like that further restricts the vertical movement range of the float valve body 21 can be provided.

A pressure suction / discharge hole 16 is provided in the partition wall 13 for applying a positive pressure and a negative pressure from the positive / negative pressure source 31 and the control air supply means 30 to the liquid surface of the closed syringe 12. The control air supply means 30 supplies a constant amount of pressurized air to the syringe 12 via the pressure suction / discharge hole 16 at a constant cycle via the pressure guiding path 32, and then supplies a constant amount of air from the inside of the syringe 12. Aspirate.

The apparatus having the above structure operates as follows. When the liquid agent is supplied to the liquid agent tank 14 while the syringe 12 is empty, the float valve body 21 of the float valve 20 has the lower end opening 15a open, so that the liquid agent is connected to the communication pipe 1.
The liquid is supplied into the syringe 12 through 5 and the float valve body 21 rises as the liquid surface 17a rises. When the liquid level reaches a certain value, the float valve body 21 moves to the lower end opening 1
5a is closed, and the supply of the liquid agent from the liquid agent tank 14 to the syringe 12 is stopped.

When the control air supply means 30 supplies a fixed amount of pressurized air from the positive / negative pressure source 31 to the syringe 12 through the pressure suction / discharge hole 16 in the state where the liquid agent is set in the syringe 12, the applied pressure is increased. Liquid surface 17a of liquid agent 17
Therefore, the amount of the liquid agent 17 corresponding to the applied pressure (the amount of air supplied to the syringe 12) is dripped from the nozzle 11.
When supplying this positive pressure, the float valve body 21 tends to be pressed against the lower end opening 15a by the positive pressure, and the float valve 20 maintains the closed state.

In the next cycle, the control air supply means 30 supplies a fixed amount of air to the syringe 1 through the pressure suction / discharge hole 16.
Aspirate from 2. This negative pressure prevents the liquid agent from dropping from the nozzle 11 (drip).

When cyclic positive pressure and negative pressure are continuously supplied by the control air supply means 30, the liquid agent in the syringe 12 is consumed. When the liquid surface 17a in the syringe 12 is above a predetermined level, the lower end opening 15a is closed due to the buoyant force acting on the float valve body 21, and the liquid agent is not replenished from the liquid agent tank 14 to the syringe 12. On the other hand, when the liquid surface 17a falls below a predetermined level, the float valve body 21 opens the lower end opening 15a to replenish the syringe 12 with the liquid agent in the liquid agent tank 14. When a negative pressure is supplied to the syringe 12 in a state where the float valve body 21 opens the lower end opening 15a even if it is slightly, the negative pressure causes the lower end opening 15a.
Since the liquid agent therein is sucked into the syringe 12, the liquid agent is surely supplied to the syringe 12. As a result, if the liquid surface 17a returns to a predetermined level, the float valve body 21
Closes the lower end opening 15a again.

As described above, according to the device of the present invention, the level of the liquid surface 17a in the syringe 12 is kept substantially constant. Therefore, the volume other than the liquid agent 17 in the closed syringe 12 is also kept constant, so that the control air supply means 30
Therefore, the discharge amount per time can be made constant only by supplying and sucking a constant amount of air. When the liquid agent in the liquid agent tank 14 has been consumed, the lid 19 may be opened and replenished appropriately.

The reason why the negative pressure is applied to the liquid surface of the syringe 12 is mainly to prevent liquid leakage from the nozzle 11. However, when the viscosity of the liquid agent supplied to the syringe 12 is high, it is simply positive. The liquid leakage can be prevented only by stopping the supply of the pressure, and in this case, the control air supply means 30 does not need to periodically supply the negative pressure.

In the above embodiment, the liquid agent tank 14 is integrally provided on the upper portion of the syringe 12, but the liquid agent tank 14 and the syringe 12 may be provided separately. Further, since the liquid agent from the liquid agent tank 14 is sucked by the negative pressure acting inside the syringe 12, it is not always necessary to provide the liquid agent on the upper portion of the syringe 12. FIG. 2 shows another embodiment of the present invention.
The liquid agent tank 14 is provided on the side of the syringe 12. In the float valve 20 of this embodiment, a valve body 23 for opening and closing the lower end opening 15a and a float 24 are provided as separate bodies, and the valve body 23 and the float 24 are integrally connected.

FIG. 3 shows still another embodiment of the float valve 20, in which a support arm 25 is provided at the lower end of the communication pipe 15.
Is integrally provided, and a swing arm 26 is supported on the support arm 25 by a shaft 25a.
5 is provided with a valve body 27 for opening and closing the lower end opening 15a and a float 28, respectively.

FIG. 4 shows an embodiment in which the float valve 20 is provided with a spring 29 for surely closing the valve. Since gravity is applied to the liquid agent 17 in the communication pipe 15, the valve closing may be uncertain only by the buoyancy acting on the float valve body 21. The spring 29 reliably presses the float valve body 21 against the lower end opening 15a against the gravity. The force of the spring 29 is set to a strength that does not hinder the descent of the float valve body 21 when the liquid surface 17a falls below a predetermined level. In this embodiment, the movement restricting member 22
A spring seat 22 'for receiving the spring 29 is formed thereat.
The float valve 20 of FIGS. 2 and 3 can be provided with a similar biasing spring.

FIG. 5 shows a preferred embodiment when the viscosity of the liquid agent is high. At the upper end of the liquid agent tank 14, a lid 19 that closes the liquid agent tank 14 is detachably provided. A positive pressure introducing passage 33 is opened in the lid body 19, and the positive pressure introducing passage 33 is connected to a positive and negative pressure source 31 via a pressure reducing valve 34. The pressure reducing valve 34 reduces the positive pressure of the positive / negative pressure source 31 to apply a pressure equal to or higher than atmospheric pressure to the liquid surface 17a in the liquid agent tank 14. Float valve 20A of this embodiment
Is an inner-outer double cylinder 36a having an annular air chamber 35 in the middle,
36b, a float body 37, a valve body 40 that opens and closes the lower end opening 15a of the communication pipe 15, and a compression spring inserted between the valve receiver 40a of the valve body 40 and the bottom wall 37a of the float body 37. It consists of 41. Float 3
The bottom wall 37a of 7 connects the lower ends of the double cylinders 36a and 36b to form an annular air chamber 35 between them. The upper end of the annular air chamber 35 is open, and the bottom wall 37a is provided with a liquid agent dropping hole 38. Float valve 20
A is slidably fitted in the communication pipe 15 in the vertical direction, and the communication pipe 15 is provided with a protrusion 15b for preventing the float valve 20A from falling off.

According to this embodiment, the buoyant force of the float valve 20A is obtained by the volume occupied by the float valve 20A in the liquid agent 17, and when the float valve 20A floats to the normal position, the force of the compression spring 41 causes the valve element 40 to move. Correctly seats on the lower end opening 15a of the communication pipe 15. The compression spring 41 is
This is effective in matching the axial center of the valve body 40 with respect to the communication pipe 15 and obtaining a reliable valve closing force. The liquid surface 17a of the liquid agent 17 in the liquid agent tank 14 is constantly subjected to a constant pressure equal to or higher than atmospheric pressure via the positive / negative pressure source 31, the pressure reducing valve 34, and the positive pressure introducing passage 33. Even when the viscosity is high, the liquid agent 17 can be surely dropped from the liquid agent discharge nozzle 11 when the positive pressure is supplied to the syringe 12. The magnitude of the positive pressure exerted on the liquid surface 17a is determined according to the viscosity of the liquid agent 17. In this embodiment, the control air supply means 30 need not supply negative pressure to the syringe 12.

6 and 7 show an embodiment in which the liquid agent does not flow to the control air supply means 30 side even if the float valve mechanism has some trouble and the liquid level in the syringe 12 rises. Is. In particular, when the control air supply means 30 is installed at a lower position than the fixed quantity dispenser, the liquid agent may flow to the control air supply means 30 side, and the liquid agent is damaged if it flows.

Control air supply means 30 via pressure guiding path 32
A check valve 43 having a spherical float valve 42 is provided in the pressure intake / exhaust hole 16 connected to. This check valve 43
A valve chamber 44, which is long in the vertical direction, is provided in a part of the pressure suction / discharge hole 16 that connects the pressure suction / discharge hole 16 and the syringe 12, and an upper end portion of the valve chamber 44 is opened and closed by a spherical float valve 42. On the other hand, the lower end portion is a valve seat 47 having a communication passage 46. In a normal state where the float valve 20 is kept at a predetermined floating position, the liquid level in the syringe 12 does not reach the check valve 43, and therefore the spherical float valve 42 is seated on the valve seat 47 by its own weight. are doing. At this time, the pressure guiding path 32 and the syringe 12 are communicated with each other by the communication path 46, and therefore, the positive and negative pressure supply from the control air supply means 30, that is, the fixed amount supply of the liquid agent is not affected at all.

On the other hand, due to some trouble, the float valve 20
When the valve closing function of A is impaired, the liquid agent in the liquid agent tank 14 is continuously supplied to the syringe 12, and the liquid level in the syringe 12 rises. Then, the liquid agent eventually becomes the valve chamber 44.
The spherical float valve 42 is pushed into the inside and pushed up, and the spherical float valve 42 is seated on the valve seat 45. Therefore, the syringe 12
Since the communication between the pressure guide passage 32 and the pressure guide passage 32 is cut off, the liquid agent in the syringe 12 can be prevented from reaching the control air supply means 30 via the pressure guide passage 32.

8 to 10 show an embodiment in which the present invention is more concrete. This embodiment is characterized by the float valve 20B having an assembling property with respect to the communication pipe 15 and a smooth sliding property. Like the float valve 20A, the float valve 20B has a float body 37B, a valve body 40, and a compression spring 41 as basic constituent elements. The float body 37B has a longer fitting length with the communication pipe 15 as compared with the embodiment of FIG. 5, and annular sliding protrusions 15c are formed on the outer periphery of the communication pipe 15 at the upper and lower sides thereof. Double cylinder inner cylinder 36a of float 37B
Makes sliding contact with the upper and lower annular sliding protrusions 15c. The float body 37B is wholly made of a synthetic resin material, and has a retaining wall 50 at its upper end portion which engages with the annular sliding protrusion 15c in the circumferential direction, as shown in FIGS. 8 and 9. The through holes 51 are formed alternately. The retaining wall 50 is elastically deformed and bent when it is fitted on the outer periphery of the communication pipe 15 and comes into contact with the annular sliding protrusion 15c with a strong force, but in the free state, it engages with the annular sliding protrusion 15c. It can be prevented from falling out. A tubular valve seat body 52 having a lower end opening 15a is fixed to the lower end of the communication pipe 15.

On the other hand, a liquid agent dropping hole 38 and a slide guide hole 54 for the valve body 40 are formed in the lower end wall 53 of the float body 37B. The guide hole 54 slidably guides the guide rod 40b of the valve receiver 40a to which the valve body 40 is fixed. The compression spring 4 is provided between the valve support 40a and the lower end wall 53.
1 is inserted, and the lower end wall 5 is attached to the guide rod 40b.
A retaining ring 55 is fixed to the protruding end from 3. The compression spring 41 is slightly compressed so that the retaining ring 55 contacts the lower surface of the lower end wall 53 when no external force is applied to the valve body 40. Further, the compression spring 41 of the valve body 40 has the lower end opening 1 at the normal floating position of the float body 37B that receives the buoyancy force of the liquid agent 17 in the syringe 12.
Its strength is set so that it firmly seats on 5a and closes. The valve support 40a of the valve body 40 has a lower end opening 1
Notch 40 for passing the liquid dropped from the gap between 5a and valve body 40
c is formed (FIG. 10).

The operation of the fixed amount dispenser having the above construction is basically the same as that of the embodiment described with reference to FIG. 5, but according to this embodiment, the float 37B slides more smoothly along the communication pipe 15. . Therefore, the liquid agent 17 in the syringe 12
The level fluctuation of the liquid surface 17a can be limited to a smaller range to perform more accurate quantitative discharge.

11 and 12 show an expensive control air supply even when the float valve mechanism has some trouble and the liquid level in the syringe 12 rises in the fixed amount dispenser having the basic structure shown in FIG. This is an embodiment in which the liquid agent is prevented from flowing to the means 30 side. Elements common to those in FIG. 8 are designated by common reference numerals. In this embodiment, a valve seat 15d and a valve seat (lower end opening) 15a are provided above and below the cylindrical valve seat body 52 provided at the lower end of the communication pipe 15, respectively.
The valve body portion 60a of the safety valve body 60 is brought into contact with or separated from the valve seat 15d, and the valve body 40 is brought into contact with or separated from the valve seat 15a as in the previous embodiment. The safety valve body 60 includes a push rod 60b extending downward from the valve body portion 60a, and the valve body 40 can be engaged with the push rod 60b. The push rod 60b of the safety valve body 60 is provided on the float valve 20.
The valve body 40 is pushed up at the normal floating position of B, and the valve body portion 60a is separated from the valve seat 15d (FIG. 11).

In the fixed amount dispenser having the above structure, at the normal floating position of the float valve 20B, the valve body 40 is seated on the valve seat 15a to close the lower end of the communication pipe 15, and at the same time, the push rod 60b of the safety valve body 60 is pushed up. Therefore, the valve body 60a is separated from the valve seat 15d to open the safety valve. In this state, it is possible to perform the same fixed amount discharge operation as that of the embodiment shown in FIGS. That is, when a positive pressure acts on the liquid surface 17a of the liquid agent 17 of the syringe 12 by the control air supply means 30, the syringe 12
When the liquid agent 17 is dripped from the nozzle 11 at the lower end of the and the negative pressure acts, the dropping is stopped. In this way, the syringe 12
When the liquid agent inside is consumed and the liquid surface 17a falls below a predetermined level, the float valve 20B descends accordingly,
The valve body 40 opens the valve seat 15a and replenishes the liquid agent in the liquid agent tank 14 to the syringe 12. When the liquid surface 17a rises, the float body 37B rises, and the force of the compression spring 41 is also obtained so that the valve body 40 closes the valve seat 15a. By repeating this operation, constant amount discharge is performed.

On the other hand, due to some trouble, the float valve 20
When the valve closing function of B is impaired, the liquid agent in the liquid agent tank 14 is continuously supplied to the syringe 12, and the liquid level in the syringe 12 rises. Then, the liquid agent enters the annular air chamber 35 of the float body 37B through the through hole 51, and eventually the float body 37B loses its buoyancy and sinks into the liquid agent 17. The valve body 40 moves together with the sinking float body 37B, so that the valve body 40 separates from the valve seat 15a. Then, since the force pushing up the safety valve body 60 disappears, the safety valve body 60 falls by its own weight, and the valve body portion 60
a sits on the valve seat 15d and closes the communication pipe 15. Therefore, the supply of the liquid agent from the liquid agent tank 14 to the syringe 12 is stopped. When the float body 37B sinks, the lower end of the guide rod 40b closes the liquid agent discharge nozzle 11,
The liquid agent does not drip from the nozzle 11 (FIG. 12).

In the normal state, the supply of the positive pressure and the negative pressure from the control air supply means 30 is not stopped even when the valve closing function of the float valve is impaired. Now, when positive pressure is supplied, positive pressure acts on the liquid surface 17a in the syringe 12,
The pressure acts on the valve body 60. As a result, the valve body 60 rises, the valve body portion 60a is separated from the valve seat 15d, and the liquid agent 17 in the syringe 12 flows back into the liquid agent tank 14. When a negative pressure is supplied, the force in the direction in which the valve body portion 60a is seated on the valve seat 15d acts on the safety valve body 60, so that the liquid in the syringe 12 does not flow back to the liquid agent 17. . Thus, when positive pressure is supplied several times, almost all of the liquid agent in the syringe 12 flows back into the liquid agent tank 14. That is, the liquid agent 17 in the syringe 12 does not flow to the control air supply means 30 side via the pressure suction / discharge hole 16 and the pressure guiding path 32.

[0038]

As described above, according to the fixed amount dispenser of the present invention, since the liquid agent level in the closed syringe is kept substantially constant, there is no special pressure control for the positive pressure supplied to the syringe. , It is possible to perform a fixed amount discharge. That is, unlike the conventional case, it is not necessary to control the supply pressure according to the lowering of the in-syringe pressurizing piston, so that a low-priced and reliable fixed-quantity dispenser can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a fixed quantity dispenser according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a sectional view showing another embodiment of the float valve.

FIG. 4 is a sectional view showing still another embodiment of the float valve.

FIG. 5 is a vertical cross-sectional view showing another embodiment of the fixed quantity dispenser according to the present invention.

FIG. 6 is a sectional view showing still another embodiment of the present invention.

7 is a sectional view taken along line VII-VII in FIG.

FIG. 8 is a vertical cross-sectional view showing a more specific embodiment of the fixed quantity dispenser according to the present invention.

FIG. 9 is a sectional view taken along line IX-IX in FIG. 8;

10 is a cross-sectional view taken along line XX of FIG.

FIG. 11 is a vertical cross-sectional view showing another more specific embodiment of the metered dose dispenser according to the present invention.

FIG. 12 is a vertical cross-sectional view showing different operating states of the fixed quantity dispenser of FIG. 11.

FIG. 13 is a cross-sectional view showing an example of a conventional fixed amount dispenser.

FIG. 14 is a graph showing a control example by the conventional device of FIG.

[Explanation of symbols]

 11 Nozzle 12 Syringe 14 Liquid Agent Tank 15 Communication Pipe 15a Valve Seat (Lower End Opening, Opening Inside Syringe) 15b Detachment Protrusion 15c Sliding Annular Protrusion 16 Pressure Suction and Discharge Hole 17 Liquid Agent 17a Liquid Level 20 20A 20B Float Valve 21 Float Valve Body 23 27 40 Valve body 24 28 Float 30 Control air supply means 31 Positive / negative pressure source 32 Pressure passage 33 Positive pressure introduction passage 35 Annular air chamber 36a 36b Inner / outer double cylinder 37 37B Float body 43 Check valve 51 Through hole 52 Cylindrical Valve seat 60 Safety valve 60a Valve seat 60b Push rod

Claims (10)

[Claims] 1. A closed syringe equipped with a nozzle for discharging a liquid agent; a liquid agent tank which communicates with the syringe via a communication pipe facing the inside of the syringe; provided in the communication pipe.
A float valve that opens and closes an opening in the syringe of the communication pipe according to the liquid level in the syringe; and a positive pressure is periodically applied to the liquid surface of the syringe, and the liquid agent in the syringe is removed each time the positive pressure is applied. A fixed amount dispenser comprising: a control air supply unit for discharging from the nozzle. 2. The fixed quantity dispenser according to claim 1, wherein the liquid agent tank is closed, and means for exerting pressure on the liquid surface is provided. 3. The liquid agent flow according to claim 1, wherein an air flow between the control air supply unit and the syringe is allowed between the control air supply unit and the syringe, and the liquid agent flow from the syringe side to the control air supply unit side. Metering dispenser equipped with a check valve to prevent 4. The valve body of the float valve according to any one of claims 1 to 3, wherein a biasing force is applied to the valve body of the float valve in a direction of closing the opening in the syringe of the communication pipe by a spring. A fixed-quantity dispenser set to a strength that does not prevent the float valve from opening when the liquid level falls below a predetermined level. 5. The float pipe according to claim 1, wherein the communication pipe is a straight pipe that is oriented in a vertical direction in a use state, and the float valve is slidably fitted on an outer periphery of the straight pipe. And a valve body which is supported by the float body via spring means and opens and closes the lower end opening of the communication pipe, and the spring means is such that the float body is located at the normal floating position by the buoyancy of the liquid agent in the syringe. A metering dispenser having the force to seat the valve body on the opening of the communicating pipe. 6. The fixed quantity dispenser according to claim 5, wherein the float body is composed of an inner and outer double cylinder forming an air chamber in the middle. 7. The float body according to claim 6, wherein when the liquid level in the syringe with respect to the float body rises from a normal position, the liquid body is guided into the air chamber between the inner and outer double cylinders. A liquid agent introducing hole for sinking inside is provided, and when the float body sinks in the opening of the communication pipe,
A metered dose dispenser equipped with a safety valve that blocks the flow of liquid from the liquid tank to the syringe. 8. The safety valve according to claim 7, wherein when the positive pressure acts on the liquid surface of the liquid agent in the syringe, the safety valve opens to allow the liquid agent in the syringe to flow to the liquid agent tank side, and the negative pressure is applied to the liquid surface. A fixed quantity dispenser that is a valve that, when activated, blocks the flow of liquid agent from the liquid agent tank into the syringe. 9. The tubular valve seat body having upper and lower end portions as valve seats is provided at the lower end opening of the communication pipe according to claim 7 or 8, and the valve above and below the tubular valve seat body is provided. When the safety valve and the valve body of the float valve come into contact with and separate from the seat, and the valve body of the float valve closes the lower end opening of the communication pipe,
A fixed quantity dispenser that opens by pushing up the valve body of the safety valve. 10. A closed syringe provided with a nozzle for discharging a liquid agent; a communication pipe facing the inside of the syringe,
Liquid agent tank that communicates with the syringe; open / close valve that opens and closes an opening in the syringe of the communication pipe provided in the communication pipe; detects the liquid level in the syringe so that the liquid level becomes almost constant An on-off valve control mechanism that controls the opening and closing of the on-off valve; and a control air supply unit that periodically applies a positive pressure to the liquid surface of the syringe, and discharges the liquid agent in the syringe from the nozzle each time the positive pressure is applied. A fixed amount dispenser characterized by comprising.