JP2000193100A - Liquid constant flow discharge valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly-precisely and stably discharge micro quantity of liquid by increasing/decreasing the volume of a liquid chamber in such a state as offsetting the fluctuation of liquid pressure generated by the movement of a needle valve element by a pressure compensating means in moving the needle valve element opening/closing a discharge port of the liquid. SOLUTION: A needle valve 10 as a discharge valve has a valve body of an air cylinder 12 form and a needle valve element 20 for quantitatively discharging pressure liquid introduced in a liquid chamber 16 via a liquid inlet 14 from a discharge port 18 is arranged therein. The needle valve element 20 is opened/ closed via a piston raised/lowered according to the feed of the compressed air to a port a1 or a2. In this case, an air chamber partitioned from an air chamber 30 by a partition 25 and partitioned from the liquid chamber 16 by a partition 27 is provided, a pressure compensating piston 26 is arranged therein, and its projecting part 26a offsets the change in the occupation volume of the needle valve element 20 generated in the liquid chamber in the movement of the needle element 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge valve suitable for use in a device for quantitatively discharging a liquid containing a viscous fluid and a viscous substance.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, for example, in a semiconductor manufacturing process, a liquid fixed-rate discharge device is used for regularly or irregularly point-applying or linearly applying an electronic material on a substrate. In such a liquid dispensing apparatus, the amount of the liquid pushed out from the liquid storage container by a pressurizing means such as a piston is controlled by the opening / closing amount and the opening / closing time of the discharge valve. There are various types of such discharge valves, and an appropriate discharge valve is properly used depending on the type of liquid to be discharged, the amount of liquid to be discharged per unit time, and the like. In particular, a discharge valve called a needle valve is provided with a needle valve body having an acute tip provided movably in the liquid chamber, and a small opening communicating with the discharge port provided at the center of the needle valve body. And a valve seat formed in the portion, the needle valve body is configured to stop liquid ejection by closing the opening at the center of the valve seat and perform liquid ejection by moving away from the opening. It has a characteristic that the effective cross-sectional area of the valve seat opening changes little with respect to a minute stroke adjustment of the valve body, and is said to be suitable for discharging a small amount of liquid because of the characteristic. Such a needle valve is disclosed in Japanese Patent Application No. 10-309179 entitled "Liquid dispensing device" filed by the present applicant (filing date: October 29, 1998).
Day).

[0003]

However, when a fixed amount of liquid is discharged by using such a needle valve, a needle valve body occupying a liquid chamber formed with an opening communicating with the liquid discharge port. Changes, that is,
Since the volume occupied by the needle valve body in the liquid chamber changes, this causes a change in the liquid pressure in the liquid chamber, and as a result, the discharge speed (discharge amount) of the liquid to be discharged is slightly changed. There's a problem. The occupied volume of such a needle valve body is minimum when the valve is open, but gradually increases from opening to closing and becomes maximum when closing, affecting the liquid discharge amount. In particular, when the discharge amount is required to be small and constant, even a small change in volume has a large effect as a variable element of the discharge amount.

A main object of the present invention is to solve the problems of the needle valve described above, and it is possible to perform a minute discharge of liquid with high accuracy and stability and to quickly stop the discharge. It is to provide a valve. Another object of the present invention is to provide a liquid meter having a pressure compensating means for increasing or decreasing the volume of a liquid chamber so as to offset a change in the liquid pressure in the liquid chamber accompanying the movement of a needle valve body for opening and closing the liquid discharge port. It is to provide a discharge valve.

[0005]

In order to achieve the above object, a liquid metering discharge valve according to the present invention comprises an inlet hole communicating with a liquid storage container, and a liquid chamber for accommodating a liquid introduced from the inlet hole. A valve body formed with an outlet hole from which the liquid in the liquid chamber is to be discharged;
A needle-shaped valve body movably provided between a position and a second position, and a valve formed such that the outlet hole is closed by receiving a tip of the valve body at a first position of the valve body. And a pressure compensating means for changing the volume of the liquid chamber in synchronization with the movement of the valve element so as to cancel the fluctuation of the liquid pressure in the liquid chamber due to the movement of the valve element. I do.

[0006] The needle-shaped valve element in such a liquid fixed-rate discharge valve is configured to control the discharge amount of liquid by moving between a first position and a second position. Since the change in the volume occupied by the valve body in the chamber, that is, the change in the fluid pressure is simultaneously canceled by the operation of the pressure compensating means, the fluid pressure in the fluid chamber is always maintained at a predetermined value, and the discharge flow rate during the valve operation is kept constant. Can be held. In particular, since a small fluctuation in the liquid pressure due to the movement of the needle valve having a small size and volume can be effectively absorbed, the liquid can be discharged with high accuracy and stability.

In the liquid metering valve of the present invention, the valve body may be formed in the form of a cylinder. In such a form, the rear end of the needle valve body is connected to a piston in the cylinder, and the pressure of the cylinder is reduced. The compensating means includes a pressure compensating piston which is provided independently of the piston and a part of which is disposed facing the liquid chamber, and the change in the volume occupied by the valve body in the liquid chamber caused by the movement of the piston is as described above. The pressure compensating piston is configured to be offset by moving the piston in a direction opposite to the moving direction of the piston.

According to such a configuration, the pressure compensating piston operates simultaneously with the forward and backward displacement of the piston of the cylinder,
Since the volume occupied by the one end of the pressure compensation piston facing the liquid chamber changes with the advance / retreat displacement of the piston,
It is possible to more easily, quickly, and accurately cope with pressure fluctuations in the discharge port and the vicinity thereof. For example, when the valve is operated to open, the volume of the needle valve body occupying the portion near the discharge port decreases, and conversely, when the valve is closed, the volume occupied by the needle valve body increases. In the case of, the pressure compensating piston is advanced and displaced, and one end thereof is advanced into the liquid chamber,
It is possible to prevent a decrease in the fluid pressure in the vicinity of the discharge, and in the latter case, to prevent the fluid pressure from increasing by displacing the pressure compensating piston backward and retreating one end thereof from the fluid chamber. be able to.

In the present invention, it is preferable that a means for adjusting the stroke length from the first position to the second position of the needle valve body is provided, and the discharge flow rate of the liquid can be controlled by adjusting the stroke length of the valve body. Can be set to the value of Furthermore, the movement of the needle valve body and the driving of the actuator forming the pressure compensating means may be respectively performed by electromagnetic driving means. In such a case, the rear end of the needle valve body is connected to a first electromagnetic drive means provided outside the valve body, and the actuator is provided with a second electromagnetic drive means provided outside the valve body. Connected to the means.

[0010] Each of the first and second electromagnetic driving means can be constituted by a step motor and a mechanism for converting the rotation of the step motor into a linear motion. In addition, the first
The electromagnetic driving means comprises a first plunger connected to the rear end of the valve body, and a first magnetic coil for driving the first plunger, and the second electromagnetic driving means comprises an actuator , And a second magnetic coil for magnetically driving the second plunger. In the discharge valve configured as described above, a pressure sensor is disposed near the valve seat in the liquid chamber to detect the liquid pressure, and based on the detection result, the driving direction of the first electromagnetic driving means and the second electromagnetic driving means is determined. And the driving time may be controlled respectively.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a liquid metering discharge valve according to an embodiment of the present invention. FIG. 1 is a cross-sectional view showing a first embodiment of the present invention. In the drawing, reference numeral 10 denotes an entire needle valve as a discharge valve. This needle valve has a valve body configured in the form of a double-acting air cylinder 12, and within this valve body,
A needle valve body 20 for discharging the pressurized liquid introduced into the liquid chamber 16 through the liquid inlet 14 from the discharge port 18 quantitatively through an inlet hole communicating with a liquid storage container (not shown). It is arranged. This needle valve body 20
The first is configured to be raised and lowered by a piston 24 in the air cylinder 10, and the needle-shaped tip is in contact with an opening at the center of the valve seat 22 to stop the discharge of liquid.
, And a position that is separated from the first position by a predetermined distance upward from the first position, and can smoothly move between the second position that gives the maximum discharge amount of the liquid discharged from the discharge port. It has become.

That is, the rear end of the needle valve body 20 is connected to the piston 24, and the front end thereof is arranged toward an opening communicating with the discharge port 18 formed at the center of the valve seat 22. The piston 24 for moving the needle valve body 20 is slidably disposed in an air chamber 30 provided in the valve body, and lowers the needle valve body 20 by supplying compressed air from a port a1. The needle valve element 20 is configured to be raised by supplying compressed air from a2.

Another air chamber 32, which is separated from the air chamber 30 by the partition wall 25 and is separated from the liquid chamber 16 by the partition wall 27, has another piston 26 (hereinafter referred to as a pressure compensation piston) independently of the piston 24. Are slidably disposed. The pressure compensating piston 26 has a needle valve body 2 fixed to the piston 24 at the center thereof.
0 is inserted so as not to hinder the smooth movement of the needle valve body 20. The pressure compensating piston 26 has a protruding portion 26 a that protrudes into the liquid chamber 16 through an opening provided in the partition 27, and has a port b provided in the air chamber 32.
It is configured to be raised by supplying compressed air from port 1 and to be lowered by supplying compressed air from port b2.

The amount of protrusion of the pressure compensating piston 26 is adjusted so that the protrusion 26a cancels the change in the volume occupied by the needle valve body 20 that occurs in the liquid chamber when the needle valve body 20 moves. That is, when the needle valve body 20 moves away from the first position as shown in FIG. 1 and moves toward the second position, the volume of the needle valve body 20 occupying the liquid chamber 16 decreases and the liquid chamber 16 As the fluid pressure rises,
To compensate for the pressure increase, the pressure compensating piston 26
Is lowered to increase the amount of protrusion, while the needle valve body 2
When 0 moves from the second position to the first position, the volume of the needle valve body 20 occupying the liquid chamber 16 increases and the liquid pressure in the liquid chamber 16 drops. ,
The pressure compensating piston 26 is raised to reduce the amount of protrusion.

The movement of the piston 24 and the movement of the pressure compensating piston 26 synchronized with the movement of the piston 24 are performed by switching the compressed air supplied from the air compressor 34 between the flow paths X and Y by the electromagnetic switching valve 36. .
The flow path X is connected to the port a1 of the air chamber 30 on the piston 24 side and the port b1 of the air chamber 32 on the pressure compensation piston 26 side, while the flow path Y is connected to the port a2 of the air chamber 30 on the piston 24 side. It is configured to be connected to the port b2 of the air chamber 32 on the piston 26 side.

In the liquid metering discharge valve of the present invention having the above-described structure, the operation of the needle valve body 20 and the operation of the pressure compensating piston can be performed in synchronization with each other, so that the discharge flow rate is always kept constant. it can. In particular, when the needle valve body 20 in the closed state is opened, the phenomenon caused by the pressure drop in the liquid chamber, for example, the inconvenience of the air being mixed into the liquid or the liquid returning from the discharge port toward the liquid chamber is eliminated. Therefore, the liquid discharge can be performed at a constant discharge flow rate immediately after the needle valve body 20 is operated, and the liquid discharge can be stopped quickly.

The outer peripheral surface of the piston 24 and the air chamber 30
Between the needle valve body 20 and the partition 25,
Sealing between the outer peripheral surface of the pressure compensating piston 26 and the side wall surface of the air chamber 32, between the outer peripheral surface of the protrusion 27 and the partition wall 27, and between the needle valve body 20 and the insertion hole of the pressure compensating piston 26. Is performed by an O-ring.

FIG. 2 is a sectional view showing a second embodiment of the present invention, and the same or similar parts as those in the first embodiment are denoted by the same reference numerals. This embodiment shows an example in which a means for adjusting the stroke length is provided for each of the piston 24 and the pressure compensation piston 26. Male screw 4 screwed into air chamber 30 from above needle valve body 12
4 is a displacement amount of the piston 24, that is, the needle valve body 2
This is for adjusting the stroke length from the first position to the second position. By screwing the screw 44 by a predetermined distance, the second position of the needle valve body 20 can be shifted further downward, so that the opening of the needle valve can be adjusted to a desired value.

A male screw 46 screwed into the air chamber 32 from the outside of the partition 25 that separates the air chamber 30 and the air chamber 32 is for adjusting the displacement of the pressure compensating piston 26 similarly. Such adjustment is desirably performed in accordance with the adjustment of the displacement amount of the piston 24. For example, when the tip of the screw 44 protrudes into the air chamber 30 to reduce the stroke of the needle valve body 20
The liquid chamber 1 of the needle valve body 20
This is because the width of increase or decrease in the volume occupied in 6 becomes small, and it is necessary to adjust the stroke length of the pressure compensating piston 26 in accordance with such an increase or decrease.

By attaching micrometers to the external threads 44 and 46 as means for adjusting the stroke length as described above, the stroke amount of each piston can be adjusted manually and quantitatively. In the first and second embodiments described above, the piston is used as the pressure compensating means. However, the pressure compensating means is not limited to this, and the change in the occupied volume in the liquid chamber 16 due to the movement of the needle valve body 20 may be reduced. It may be constituted by means capable of changing the volume of the liquid chamber in synchronization with the movement of the valve element so as to cancel each other, for example, a diaphragm or a bellows.

FIG. 3 is a schematic diagram of a system in which the needle valve according to the first embodiment of the present invention is applied to a liquid fixed-rate discharge system. In the figure, reference numeral 1 denotes a liquid storage container, which here comprises a syringe 3 made of, for example, a synthetic resin material, and a holder 4 that circumscribes and holds the syringe 3. The attachment and detachment of the syringe 3 is possible.

The pressurizing means 5 for applying the liquid in the liquid storage container 1 to a required pressure is constituted by an air cylinder 6, which is provided at the tip of a piston rod 7 thereof, preferably at the syringe 3. A plunger 8 that inscribes airtightly and enters there is attached. Such a liquid storage container 1 is connected to a valve body of a needle valve via a liquid flow path 9. Although the internal structure of the valve body is omitted in FIG. 4, a needle valve as described in the first embodiment is employed here. The flow path 9 is connected to a liquid inlet 14 formed in the valve body 12, and the liquid chamber 16 is connected to the valve seat 2.
2 through the opening formed in the central portion. The needle valve body 20 that moves forward and backward in the liquid chamber 16 to open and close the discharge port 18 is configured to be operated by the air cylinder 10, and the tip of the needle valve body 20 faces the center opening of the valve seat 22. It is arranged and its rear end is connected to the piston 24 of the cylinder 10. Further, between the liquid chamber 16 and the piston 24, a liquid pressure compensating piston 26 independent of the piston 24 is provided. The pressure compensating piston 26 reduces the volume of the liquid chamber 16 when the pressurized air is supplied to the air chamber 32 of the piston 24 and is advanced and displaced.
When the pressurized air is supplied to the air chamber 27 on the side and is displaced backward, it functions to increase the volume of the liquid chamber 16.

Therefore, when the liquid pressure in the vicinity of the discharge port 18 is lower than a predetermined value, the pressure compensation piston 2
6 is advanced slightly, and if it is higher than a predetermined value, the pressure compensating piston 26 is slightly retracted to achieve the expected hydraulic pressure. Here, an air cylinder 6 for pressurizing the liquid storage container 1 and a double-acting air cylinder 10 for moving the needle valve body 20 back and forth are connected to the respective electromagnetic switching valves 5.
2, 36, and these electromagnetic switching valves 52,
36 is connected to control means 54 for controlling the operation based on a time signal inputted in advance, and one electromagnetic switching valve 52 for controlling the supply of pressurized air to the air cylinder 6.
From the pressurized air supply 3 via a manual pressure reducing valve 56, for example.
3, and the other electromagnetic switching valve 36 is connected directly to the pressurized air supply 34, respectively.

In the fixed-rate discharge device thus configured, a signal is output from the control means 54 to each of the electromagnetic switching valves 52 and 36 at the time of the fixed-rate discharge of the liquid, and the signal is output to the air cylinder 6 by the manual pressure reducing valve 56. The set air pressure is supplied to lower the plunger 8 with a required force, and at the same time, the air cylinder 10
A predetermined air pressure is supplied to the input ports a2 and b2 of the nozzles to raise the piston 24 to raise the needle valve body 20 from the first position to the second position. By lowering the pressure compensating piston 26 so as to offset the reduction in volume occupied in the space 16, the liquid pressurized to the required pressure is specified from the discharge port 18 in relation to the opening area thereof. Since the liquid can be discharged for a certain period of time, the liquid can be discharged at a high precision without a time lag.

On the other hand, when terminating the fixed amount discharge, the supply of the pressurized air to the air cylinder 6 is stopped at the same time as the supply of the pressurized air to the air cylinder 6 is stopped based on the discharge end signal from the control means 54 to the electromagnetic switching valves 52, 36. 10 ports a1
And pressurized air is supplied to b1 to lower the piston 24 to lower the needle valve body 20 from the second position to the first position, and to increase the volume occupied by the needle valve body 20 in the liquid chamber 16. By raising the pressure compensating piston 26 so as to cancel each other, the discharge port 18 is connected to the needle valve body 20.
To secure the mechanical closure. Therefore, the discharge port 18
Is completely stopped by closing the needle valve 10, and the risk of liquid leakage during the closing of the needle valve 10 is sufficiently eliminated.

In this case, the needle valve element 20 having a small size and volume, which constitutes the needle valve 10,
Regardless of the magnitude of the liquid pressure, the outlet port 18 is opened and closed smoothly and quickly by always moving backward and forward, so that excellent responsiveness can be realized in addition to the certainty of the opening and closing of the needle valve 10. it can.

In the liquid dispensing apparatus using a needle valve as described above, the volume of the needle valve body 20 occupying the liquid chamber 16 is reduced by the retreat displacement of the needle valve body 20 at the start of liquid discharge. The pressure compensating piston 26 is advanced when the hydraulic pressure is reduced due to the pressure drop, and conversely, when the occupied volume when the discharge is stopped due to the advanced displacement of the needle valve body 20, the piston 26 , The subtle pressure fluctuation can be effectively absorbed.

FIG. 4 is a sectional view showing a third embodiment of the present invention. In this embodiment, the movement of the needle valve body 20 between the first position and the second position in the liquid chamber 16 is as follows.
The rear end of the needle valve body 20 is driven by a motor, and is connected to a mechanism 44 that converts the rotation of the motor 42 into a linear motion. Further, the pressure compensating means is constituted by an actuator 46 driven by a motor. One end of the actuator 46 faces the inside of the liquid chamber 16 and the other end is
The mechanism is connected to a mechanism 50 for converting the rotation into a linear motion.
The sealing between the needle valve element 20 and the actuator 46 and the valve body 12 is performed by an O-ring.

The needle valve 20 is moved up and down (advanced and retracted) and the liquid chamber 1 of the actuator 46 is driven by the motor.
The movement into and out of 6 is controlled by control device 37. When the needle valve body 20 moves from the first position to the second position (discharge of liquid), the actuator 46 is moved inside the liquid chamber 16 so as to offset the decrease in the volume of the needle valve body 20 in the liquid chamber 16. On the other hand, when the needle valve body 20 moves from the second position to the first position (stops discharging the liquid), the increase in the volume of the needle valve body 20 in the liquid chamber 16 is offset. The motors 42 and 48 are driven synchronously so that the actuator 46 retracts from the inside of the liquid chamber 16.

FIG. 5 is a schematic sectional view showing a fourth embodiment of the present invention. In this embodiment, the movement of the needle valve body 20 between the first position and the second position in the liquid chamber 16 is performed by the electromagnetic driving device 59. The electromagnetic driving device 59 includes a magnetic coil 62 for magnetically driving a plunger 60 connected to the rear end of the needle valve body 20.
And a fixed core 64 for stabilizing a magnetic field generated by the magnetic coil 62. The plunger 60 has a coil spring 6 at its lower end and upper end, respectively.
6, 68, the coil spring 66 pushes up the plunger 60, and the coil spring 68 pushes down, so that the needle valve body 20 connected to the plunger 60 as a whole is
It is configured to close. That is, such a plunger 60 normally has the coil spring 68
Is pushed down by the action of the predominant spring force. To move the plunger 60 upward from this state to open the discharge port 18, a current that can move against the spring force is supplied from the control device 80 to the magnetic coil 6.
2 is supplied. When the supply of such current is stopped, the plunger 60 is pushed down by the spring force of the coil spring 68, so that the discharge port 18 is immediately closed.

On the other hand, the pressure compensating means for canceling the change in the volume of the liquid chamber 16 due to the movement of the needle valve body 20 includes:
Actuator 7 moved back and forth by electromagnetic drive 69
It consists of 0. The electromagnetic drive device 69 includes a plunger 71 formed integrally with the actuator 70,
A magnetic coil 72 for magnetically driving the plunger 71 and a fixed core 74 for stabilizing a magnetic field generated by the magnetic coil 72 are provided.

The operation of the electromagnetic drive device 69 is controlled by the control device 80
The plunger 71 is configured to be moved leftward or rightward by interaction with a magnetic field generated by the magnetic coil 72 to which the current has been supplied. Is done. The plunger 71 is supported at both ends by a leaf spring 76 and a coil spring 78, respectively. In the illustrated state, the leaf spring 76 pushes the plunger 71 to the right and the spring coil 78 pushes to the left, but the plunger 71 is urged to the right by the predominant spring force of the leaf spring 76. , The tip of the actuator 70 is the liquid chamber 1
6 so as to protrude slightly.

When the needle valve body 20 is moved upward in the liquid chamber 16 from such a state, a predetermined current is supplied from the control device 80 to the electromagnetic drive device 59, and the magnetic coil 62 is excited. At the same time, a predetermined current is also supplied to the electromagnetic driving device 69 in synchronization with the
2 are excited. The current supplied from the control device 80 to the magnetic coil 62 moves the needle valve body 20 from the first position to the second position.
Similarly, the current supplied to the magnetic coil 72 is set to a value that moves the needle valve 20 in the liquid chamber 16 by a distance that cancels the decrease in the volume occupied by the needle valve body 20 in the liquid chamber 16. The pressure fluctuation in the liquid chamber 16 due to the upward movement of the needle valve body 20 is offset by the entry of the actuator 70 into the liquid chamber 16 because the value is set in advance so as to move the actuator 70. Become.

When the supply of such a current is stopped,
The needle valve body 20 is quickly pushed down from the second position to the first position by the spring force of the coil spring 68, and at the same time, the plunger 71 is moved rightward toward the original position by the spring force of the leaf spring 76. Moved quickly. Even when the needle valve body 20 moves downward, the pressure fluctuation in the liquid chamber 16 is canceled by the plunger 71, so that the pressure in the liquid chamber 16 is always kept constant. Therefore, when the valve shifts from the open state to the closed state, the liquid ejection speed of the paste or the like does not increase as in the related art, so that it is suitable for line drawing application with a uniform width.

When the needle valve as described above is applied to the liquid dispensing apparatus, when the work as the object to be applied with the liquid is appropriately displaced in relation to the timing of discharging the liquid, etc. In addition, the position of the needle valve as the discharge valve can be fixed for use.

However, when the work is to be positioned and fixed at a specific position, it is necessary to move the needle valve to a required position and direction. In such a case, for example, the needle valve 2 is attached to a rectangular coordinate type three-dimensional manipulator, and this manipulator is
By operating the controller that outputs a position signal based on the signal from the above-described control device, the discharge port 18 of the needle valve can be brought to a required position in the three-dimensional coordinate system, and the tact transfer is performed on a conveyor. It can be used for workpieces that have excellent application efficiency.

[0037]

As described above, according to the present invention,
During the movement of the needle valve body that opens and closes the liquid discharge port, the pressure compensating means increases or decreases the volume of the liquid chamber so as to offset the fluctuation of the liquid pressure caused by the movement of the needle valve body, so that the minute discharge of liquid can be performed with high precision In addition, it can be performed stably. In particular, such a conventional phenomenon that the pressure in the liquid chamber is reduced at the time of liquid discharge, such as the inconvenience of the air being mixed into the liquid or the liquid returning from the discharge port toward the liquid chamber, is solved. Immediately after activation, liquid discharge can be performed at a constant discharge flow rate, and liquid discharge can be stopped quickly.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

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

FIG. 3 is a schematic explanatory view when the needle valve according to the first embodiment is applied to a liquid fixed-rate discharge system.

FIG. 4 is a sectional view showing a third embodiment of the present invention.

FIG. 5 is a sectional view showing a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid storage container 3 Syringe 4 Holder 5 Pressurizing means 6 Cylinder 7 Rod 8 Plunger 9 Liquid flow path 10 Needle valve 12 Valve main body 14 Liquid inlet 16 Liquid chamber 18 Discharge port 20 Needle valve body 22 Valve seat 24 Piston 25, 27 Partition wall 26 Pressure compensation piston 30, 32 Air chamber 34 Compressed air supply source 36 Electromagnetic switching valve 37 Controller 38, 40 Adjustment screw 42 Motor 44 Converter 46 Actuator 48 Motor 50 Converter 52 Electromagnetic switching valve 54 Controller 56 Manual pressure reducing valve 59, 69 Electromagnetic drive device 60, 71 Plunger 62, 72 Magnetic coil 64, 74 Fixed core 66, 68, 78 Coil spring 70 Actuator 80 Control device

Claims (6)

[Claims] 1. A liquid storage container having an inlet hole communicating with a liquid storage container, a liquid chamber for storing liquid introduced from the inlet hole, and an outlet hole from which the liquid in the liquid chamber is to be discharged. A valve body, a needle-shaped valve body movably provided between a first position and a second position in the liquid chamber, and the outlet hole receiving the distal end of the valve body at the first position of the valve body. Pressure compensation for changing the volume of the liquid chamber in synchronization with the movement of the valve element so as to cancel the fluctuation of the liquid pressure in the liquid chamber caused by the movement of the valve element, and the valve seat formed to be closed. And a liquid dispensing valve. 2. The valve body is configured in the form of a cylinder, a rear end of the valve body is connected to a piston of the cylinder, the pressure compensating means is provided independently of the piston, and a part thereof is provided in the liquid chamber. A pressure compensating piston disposed in front of the fluid compensating piston. Fluctuations in the fluid pressure in the fluid chamber are offset by a movement of the pressure compensating piston in a direction opposite to a moving direction of the piston. The liquid fixed-quantity discharge valve according to claim 1, wherein: 3. The liquid metering valve according to claim 1, further comprising means for adjusting a stroke length of the valve element from a first position to a second position. 4. The valve body is driven by first electromagnetic driving means provided outside the valve body, and the pressure compensating means is constituted by an actuator having one end facing the liquid chamber. The liquid metering valve according to claim 1, wherein the other end is connected to a second electromagnetic driving means disposed outside the valve body. 5. The liquid metering discharge valve according to claim 4, wherein each of the first and second electromagnetic driving means includes a motor and a mechanism for converting the rotation into a linear motion. 6. The first electromagnetic driving means includes a first plunger connected to a rear end of a valve body, and a first magnetic coil for driving the first plunger. The second electromagnetic driving means comprises a second plunger connected to one end of the actuator, and a second magnetic coil for magnetically driving the second plunger. Item 5. A liquid metering discharge valve according to Item 4.