JP2003284935A - Mixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize a flow rate of a chemical liquid by absorbing temporary increase in the flow rate due to the valve closing action of an on/off valve. <P>SOLUTION: A mixing device 10 is constituted so that 50% hydrofluoric acid (chemical liquid) fed through a chemical liquid supply path 12 and pure water fed through a pure water supply path 14 are mixed by a mixing nozzle 16. When compressed air is supplied to the on/off valve 43 through an air duct 43a by an air supply circuit 39, the compressed air is also supplies to a flow rate stabilization part 44. When compressed air supply to the air duct 43a is stopped by the air supply circuit 39, compressed air supply to the flow rate stabilization part 44 is stopped at the same time. In such a way, the on/off valve 43 and the flow rate stabilization part 44 are operated in conjunction with each other to supply and stop the compressed air. The flow rate stabilization part 44 absorbs a flow rate change due to the valve closing action of the on/off valve 43 to stabilize the supply amount of the chemical liquid supplied to the mixing nozzle 16. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixing device for supplying a mixed liquid used in a flat panel display manufacturing process such as semiconductor and liquid crystal by mixing a plurality of liquid chemicals having different components.

[0002]

2. Description of the Related Art A mixing device for mixing pure water and a chemical liquid will be described as an example of a mixing device for mixing two kinds of liquids.

Conventionally, in a mixing device for mixing two kinds of chemical liquids having different components, a chemical liquid pressure-fed by nitrogen gas or the like is injected at a constant flow rate into pure water controlled to have a constant flow velocity and a constant pressure so that a predetermined concentration is obtained. It is configured to obtain a drug solution.

Further, in the conventional mixing device, an air-driven on-off valve is provided in each liquid supply path. This on-off valve opens and closes the liquid flow path by allowing the valve element to separate from and seat on the valve seat provided in the liquid flow path, and the valve element is separated from the valve seat by the supply of air to mix the liquid. The valve body is configured to be supplied to the passage, and when the supply of air is stopped, the valve body is seated on the valve seat to stop the supply of liquid.

In the thus configured mixing device, when a predetermined amount of the chemical liquid is stored in the chemical liquid storage tank, the air-driven open / close valve is opened to turn the chemical liquid into pure water with a minute flow rate by the pressure of nitrogen gas. Mix. For example, when the mixing ratio of the chemical liquid and the pure water is, for example, 1:99, the liquid amount of the generated mixed liquid is 20 L.
(Liter), the supply amount of the chemical solution is 200 mL (milliliter), while the supply amount of pure water is 1980.
It becomes 0 mL.

[0006]

An example of an on-off valve whose valve body is a diaphragm so that liquid leakage does not occur in the air-operated on-off valve provided in the mixing apparatus as described above will be described. The on-off valve sucks a certain amount of chemical liquid in the flow passage according to the area of the diaphragm by the opening operation of the diaphragm, and a certain amount of chemical liquid in the flow passage according to the area of the diaphragm in the flow passage by the closing operation of the diaphragm. Extrude into.

Therefore, in the conventional mixing device using the opening / closing valve having such a diaphragm that opens and closes as a valve body, the opening / closing valve is opened when a certain amount of the liquid medicine in the liquid medicine storage tank is discharged into the mixing passage. The valve is switched to the closed state, but at that time the diaphragm closing action pushes a certain amount of chemical solution into the flow path according to the diaphragm area, so the concentration of the mixed solution mixed in the mixing path temporarily increases. There was a problem of doing.

Further, the above-mentioned problems similarly occur in other than the opening / closing valve in which the diaphragm is opened / closed as a valve body.

Therefore, an object of the present invention is to provide a mixing device which solves the above problems.

[0010]

In order to solve the above problems, the present invention has the following features. Claim 1
In the invention described, a plurality of fluid supply paths for individually supplying different types of fluids, a plurality of on-off valves arranged for each of the plurality of fluid supply paths, and the downstream ends of the plurality of fluid supply paths merge, A mixing path in which a plurality of types of fluids are mixed and supplied,
In the mixing device, the flow control means is provided downstream of the opening / closing valve to absorb the increase in the flow rate due to the closing operation of the opening / closing valve and keep the supply amount to the mixing path constant. It is possible to stabilize the concentration of the mixed fluid by preventing the fluid supply amount from varying with the valve closing operation.

According to the second aspect of the present invention, the on-off valve is constructed such that the valve portion is displaced by the supply of air to open the valve portion, and a certain amount of fluid corresponding to the area of the valve portion is pushed out into the flow passage. This can be prevented and the concentration of the mixed fluid can be stabilized.

According to the third aspect of the invention, the flow rate stabilizing means operates the pressure receiving portion so as to absorb the increase in the flow rate due to the closing operation of the on-off valve when the air supply to the on-off valve is stopped. Since the adjustment unit is provided, it is possible to prevent a certain amount of fluid corresponding to the area of the valve portion of the on-off valve from being pushed out into the flow path and stabilize the concentration of the mixed fluid.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a schematic configuration of an embodiment of the mixing apparatus according to the present invention. As shown in FIG. 1, the mixing device 10 includes, for example, a chemical liquid supply path 12
50% hydrofluoric acid (chemical solution) supplied through the nozzle and pure water supplied through the pure water supply passage 14 are mixed by a mixing nozzle 16 to obtain a wafer (not shown) in a semiconductor manufacturing line.
Is configured to supply. In addition, hydrofluoric acid is an aqueous solution of hydrogen fluoride (hydrogen fluoride), and is hereinafter referred to as a “chemical solution (HF solution)”.

The chemical liquid supply path 12 is composed of a chemical liquid supply line 18
And the nitrogen gas supply pipeline 20 are connected to the upper part of the storage tank 22, and the chemical liquid discharge pipeline 24 drawn out from the bottom of the storage tank 22 communicates with the mixing nozzle 16. Further, an air-driven on-off valve 43 and an on-off valve 4 are provided in the chemical liquid discharge line 24.
Flow rate stabilizing unit (flow rate stabilizing means) 44 provided downstream of
Is provided.

The flow rate stabilizing unit 44 absorbs a change in flow rate associated with the closing operation of the opening / closing valve 43, as described later, and mixes the mixing nozzle 1 with it.
It is intended to stabilize the supply amount of the chemical liquid supplied to No. 6.

Further, in the nitrogen gas supply line 20, a pressure reducing valve 26 for reducing the chemical liquid supply pressure to a predetermined pressure, a mass flow meter 27 for measuring the mass flow rate of nitrogen gas, and a gas filter for removing fine particles in nitrogen gas. 28, an air-driven flow rate adjusting valve 30 for adjusting the flow rate of nitrogen gas is provided. An ultrasonic vortex flowmeter 32 for measuring the flow rate of the chemical solution and an air-driven on-off valve 34 for controlling the supply rate of the chemical solution are arranged in the chemical solution supply conduit 18.

The ultrasonic type vortex flowmeter 32 includes a chemical liquid supply line 1
The flow rate of the chemical solution (HF solution) supplied from 8 is measured, and an analog signal proportional to the flow rate is transmitted from the transmitter 32a to the control circuit 40. Then, the control circuit 40
The opening / closing valve 34 is opened / closed based on the flow rate measurement value obtained from the analog signal.

The mass flow meter 27 includes a nitrogen gas supply line 20.
The flow rate of the nitrogen gas supplied from the sensor is measured, and an analog signal having a cycle proportional to the flow rate is transmitted from the transmitter 27a to the control circuit 40. Then, the control circuit 40 controls the valve opening degree of the flow rate adjusting valve 30 so that the analog signal becomes stable at the set value.

The storage tank 22 serves to stably store the chemical liquid (HF liquid) by temporarily storing the chemical liquid (HF liquid) supplied from the chemical liquid supply pipeline 18. Also, the storage tank 2
An air-operated relief valve 37 for degassing and a pressure sensor 38 for measuring the pressure are provided on the upper part of 2. The relief valve 37 is opened at the time of injecting the chemical liquid and exhausts the nitrogen gas remaining inside the storage tank 22 to the outside, thereby reducing the load at the time of injecting the chemical liquid.

The detection signal from the pressure sensor 38 is input to the control circuit 40, and the control circuit 40 manages the pressure in the storage tank 22. In addition, the chemical liquid discharge conduit 24
Is provided with an air-driven on-off valve 43, and the on-off valve 43 is opened or closed by a control signal from the control circuit 40.

The pure water supply passage 14 has a temperature adjusting unit 46 for adjusting the temperature of the pure water to a predetermined temperature in the pure water supply pipe 45, a flow meter 48 for measuring the flow rate of the pure water, and a pure water supply unit 45. A flow rate adjusting valve 50 that adjusts the supply amount is provided. The flow meter 48 measures the flow rate of the pure water supplied from the pure water supply path 14, and sends an analog signal having a cycle proportional to the flow rate from the transmitter 48a to the control circuit 40. Then, the control circuit 40 controls the valve opening degree of the flow rate adjusting valve 50 based on the flow rate measurement value obtained from this analog signal.

The on-off valves 34 and 43 have an air-driven normally closed valve structure, and are opened by the air (compressed air) supplied from the air supply circuit 39. The air supply circuit 39 includes the flow rate adjusting valve 30 and the opening / closing valve 3.
4, 43 and the air conduit 30 connected to the flow rate stabilizing unit 44
Solenoid valves (not shown) for selectively supplying compressed air from an air source 41 composed of a compressor or the like are provided to a, 34a, 43a, 44a.

Therefore, in the air supply circuit 39, based on the control signal from the control circuit 40, the air pipelines 30a, 34
a, 43a, 44a is turned on or off to adjust the valve opening of the flow rate adjusting valve 30, and the on-off valve 3
The valves 4, 43 are opened or closed, and the diaphragm 82 of the flow rate stabilizing unit 44 is operated.

The air conduit 44a is the air conduit 43a.
It has been branched from. Therefore, when the compressed air is supplied to the on-off valve 43 via the air conduit 43a by the air supply circuit 39, the compressed air is also supplied to the flow rate stabilizing unit 44. Further, when the supply of compressed air to the air conduit 43a is stopped by the air supply circuit 39, at the same time, the flow rate stabilization unit 44
The supply of compressed air to is also stopped. In this way, the opening / closing valve 43 and the flow rate stabilizing unit 44 are supplied / stopped so that the compressed air is operated in an interlocking manner.

The chemical liquid supply line 18 and the pure water supply line 45 are half-loroalkoxy copolymer (PFA resin) or polyvinylidene fluoride (PVDF resin).
It is formed of a material in which the elution of impurities such as and the generation of fine particles are extremely small.

In the memory of the control circuit 40, a flow rate adjusting valve 50 arranged in the pure water supply pipe line 45 at the time of starting the fluid supply.
Also, the flow rate adjusting valve 30 and the opening / closing valve 43 arranged in the chemical liquid discharge pipeline 24 for supplying the chemical liquid are opened, and the flow rate adjustment arranged in the chemical liquid discharge pipeline 24 for supplying the chemical liquid is stopped when the fluid supply is stopped. A control program (control means) for closing the valve 30, the opening / closing valve 43, and the flow rate adjusting valve 50 arranged in the pure water supply conduit 45 is stored.

FIG. 2 is an enlarged vertical sectional view showing the structure of the mixing nozzle 16. As shown in FIG. 2, the mixing nozzle 16 includes a nozzle body 52 formed in a conical shape, a nozzle flow path 54 penetrating the nozzle body 52, and a nozzle flow path 5.
4 and a needle pipe 56 that obliquely intersects the direction in which the angle α is inclined with respect to 4.

A pure water supply pipe 45 is communicated with an inlet 54a of the nozzle flow path 54, and a discharge port 54b of the nozzle flow path 54 discharges a liquid in which a chemical liquid and pure water are mixed at a predetermined ratio. To do. Further, at the inlet 56a of the needle pipe 56,
The chemical liquid discharge conduit 24 is in communication. The discharge port 56b formed at the tip of the needle pipe 56 extends to the center of the nozzle flow path 54 and is bent in the discharge direction.

Therefore, the chemical solution supplied to the storage tank 22 is
It is discharged from the needle pipe 56 to the center of the nozzle channel 54 by the pressure of nitrogen gas. At this time, the chemical liquid is ejected at a very small flow rate, but since it is ejected into the pure water flowing through the nozzle flow path 54, it does not become a liquid droplet, and a predetermined amount is maintained while maintaining the uniformity with the pure water flowing around. Mixed in proportion. Further, since the needle pipe 56 supplies a very small amount of the chemical liquid, it is formed of a small-diameter pipe, and its tip portion is narrowed. Then, the chemical liquid discharged from the needle pipe 56 to the center of the nozzle channel 54 is
Is mixed with the surrounding pure water flow and supplied to a wafer (not shown) in the semiconductor manufacturing line.

The nozzle body 52 is molded of tetrafluoroethylene resin (PTFE) having excellent chemical resistance, and has a structure in which impurities are less likely to elute in the fluid.

FIG. 3 is a vertical sectional view showing a closed state of the opening / closing valve 43. As shown in FIG. 3, the on-off valve 43 includes a valve seat 60 in the housing 58, a diaphragm 62 that is seated on and off the valve seat 60, a piston 64 connected to the diaphragm 62, and a piston 64 in a valve closing direction. It has a coil spring 66 for urging, and an air inlet 70 for supplying compressed air to the cylinder chamber 68.

The valve seat 60 is formed between the inflow side flow passage 71 and the outflow side flow passage 73 in the housing 58 and faces the central portion of the diaphragm 62. An air conduit 43a communicates with the air introduction port 70. Therefore, the compressed air from the air supply circuit 39 is
It is introduced into the cylinder chamber 68 via a.

A peripheral portion of the diaphragm 62 is sandwiched by the housing 58, and a central portion of the diaphragm 62 is held so as to be displaceable in the opening / closing direction. Further, the diaphragm 62 has an end portion of a shaft 72 extending downward from the piston 64 joined to the center of the upper surface.

The cylinder chamber 68 communicates with a diaphragm chamber 74 which contacts the upper surface of the diaphragm 62. Therefore, when the compressed air is not supplied to the cylinder chamber 68, the diaphragm 62 is seated on the valve seat 60 by transmitting the spring force of the coil spring 66 via the piston 64.

Further, the piston 64 is the diaphragm 6
It has a pressure receiving area larger than 2, and as shown in FIG. 4, when compressed air is supplied to the cylinder chamber 68, it moves upward (valve opening direction) against the spring force of the coil spring 66. . As a result, the diaphragm 62 separates from the valve seat 60 and the fluid flowing from the inflow side flow passage 71 flows out to the outflow side flow passage 73.

Since the peripheral edge of the diaphragm 62 is sandwiched by the housing 58, it has a sealing structure for preventing fluid from leaking to the diaphragm chamber 74. Therefore, in the on-off valve 43, the diaphragm 62 moves downward (valve closing direction) at the time of valve closing operation, and at the same time, the diaphragm 62 pushes out the fluid corresponding to the volume displaced. Therefore, downstream of the on-off valve 43, the flow rate temporarily increases with the closing operation of the diaphragm 62.

Therefore, the chemical liquid supplied from the chemical liquid discharge conduit 24 to the mixing nozzle 16 is supplied at a constant flow rate little by little due to the pressure of the nitrogen gas in the storage tank 22, but only at the moment when the diaphragm 62 is closed. The flow rate increases and the concentration changes.

FIG. 5 is a vertical sectional view showing the structure of the flow rate stabilizing portion 44. As shown in FIG. 5, the flow rate stabilizing unit 44 is
Inside the housing 78, a valve seat 80, a diaphragm (pressure receiving portion) 82 facing the valve seat 80, a piston 84 connected to the diaphragm 82, a coil spring 86 for urging the piston 84 upward, and a cylinder chamber 88. And an air inlet 90 for supplying compressed air.

The valve seat 80 is formed between the inflow side flow passage 91 and the outflow side flow passage 93 in the housing 78, and faces the central portion of the diaphragm 82. The air inlet 90 is provided so as to supply compressed air to the cylinder chamber 88 formed on the upper surface side of the piston 84. Therefore, the piston 84 is provided so as to perform an operation reverse to that of the opening / closing valve 43.

Further, at the air inlet 90, the air pipe 4
The air pipeline 44a branched from 3a is communicated.
Therefore, the compressed air from the air supply circuit 39 is introduced into the cylinder chamber 88 via the air pipelines 43a and 44a. When the compressed air is supplied to the cylinder chamber 88 from the air inlet 90, the diaphragm 82 is displaced downward in conjunction with the opening operation of the opening / closing valve 43.

A peripheral portion of the diaphragm 82 is sandwiched by the housing 78, and a central portion of the diaphragm 82 is held so as to be vertically displaceable. Further, the diaphragm 82 has an end portion of a shaft 92 extending downward from the piston 84 joined to the center of the upper surface.

The cylinder chamber 88 is separated from the diaphragm chamber 94, which is in contact with the upper surface side of the diaphragm 82, via a piston 84, and is formed so that the pressure of compressed air acts on the upper surface of the piston 84. Therefore, when compressed air is supplied to the cylinder chamber 88, the piston 84
It moves downward against the spring force of the coil spring 86. As a result, the diaphragm 82 is displaced in the direction of approaching the valve seat 80, but is sufficiently separated from the valve seat 80.
The fluid that has flowed in from the inflow-side flow passage 91 flows out to the outflow-side flow passage 93 with a constant flow rate without changing the flow rate.

Further, as shown in FIG. 6, when the compressed air is not supplied to the cylinder chamber 88, the diaphragm 82 has an upward direction in which the spring force of the coil spring 86 is transmitted via the piston 84 to separate from the valve seat 80. Is displaced to. As a result, the flow rate stabilizing unit 44 causes the diaphragm 82 to
The upward movement expands the volume of the flow path formed between the valve seat 80 and the valve seat 80.

The space created by the upward movement of the diaphragm 82 becomes a flow rate adjusting space for absorbing a temporary increase in the flow rate by separating from the valve seat 80. Therefore, the flow rate stabilizing unit 44 stabilizes the flow rate flowing into the mixing nozzle 16 by moving the diaphragm 82 upward.

Since the peripheral edge of the diaphragm 82 is sandwiched by the housing 78, it has a sealing structure for preventing fluid from leaking to the diaphragm chamber 84. In addition, at the top of the housing 78, the piston 84
An adjusting bolt 96 for restricting the upward movement position of the is screwed. Therefore, the upward movement position of the piston 84 is adjusted by adjusting the protruding length of the adjusting bolt 96 in the cylinder chamber 88. As a result, the displacement amount of the diaphragm 82 is also adjusted.

It is possible to adjust the volume of the space formed by the upward movement of the diaphragm 82. Therefore, in the present embodiment, the volume of the space formed by the upward movement of the diaphragm 82 is adjusted to be larger than the pushing amount that occurs during the closing operation of the opening / closing valve 43. As a result, the amount of pushing that occurs during the closing operation of the opening / closing valve 43 can be reliably absorbed by the upward movement of the diaphragm 82.

FIG. 7 is a flow chart showing the control processing executed by the control circuit 40. As shown in FIG. 7, when the power switch (not shown) is turned on in step S11 (hereinafter “step” is omitted), the control circuit 40 proceeds to step S12, and the chemical liquid supply conduit 18 The open / close valve 34 and the relief valve 37 are opened to supply the stock solution of the HF solution to the storage tank 22. As described above, when the chemical liquid is supplied to the storage tank 22, by opening the on-off valve 34 and the relief valve 37, the pressure of the storage tank 22 is reduced to the atmospheric pressure, so that the liquid surface rises due to the supply of the chemical liquid. Since the pressure increase due to the above is avoided and the injection load of the corresponding chemical solution is reduced, it becomes possible to supply a predetermined amount of the chemical solution to the storage tank 22 in a short time.

In the next step S13, it is checked whether or not the flow rate value of the chemical liquid (HF liquid) measured by the ultrasonic vortex flowmeter 32 has reached a predetermined value (target value) set in advance.
In S13, the storage tank 2 is operated until the flow rate value measured by the ultrasonic vortex flowmeter 32 reaches a preset predetermined value.
The chemical supply to No. 2 continues. Then, in S13, when the flow rate value measured by the ultrasonic vortex flowmeter 32 reaches a preset predetermined value, the process proceeds to S14, and the opening / closing valve 34 and the relief valve 37 are closed.

Subsequently, in S15, it is checked whether or not the supply request signal is transmitted from the upper processor, and the supply request signal is transmitted, and the process proceeds to S16.
The flow rate adjusting valve 50 arranged in the pure water supply conduit 45 for supplying the fluid (pure water) having a higher mixing ratio is opened first. Subsequently, in S17, the valve opening degree of the flow rate adjusting valve 50 is adjusted based on the flow rate value measured by the flow meter 48.

In the next S18, it is checked whether the flow rate value (instantaneous flow rate) measured by the flow meter 48 is a predetermined value. In S18, when the flow rate value (instantaneous flow rate) measured by the flow meter 48 is not the predetermined value, the process returns to S17,
The valve opening of the flow rate adjusting valve 50 is adjusted.

If the flow rate value (instantaneous flow rate) measured by the flow meter 48 reaches a predetermined value in S18, the flow proceeds to S19 to supply the fluid (chemical solution) having the lower mixing ratio. The regulating valve 30 and the opening / closing valve 43 are opened to supply the nitrogen gas to the storage tank 22, and the storage tank 2 is operated at the gas pressure.
The chemical liquid of No. 2 is supplied to the mixing nozzle 16.

That is, since the on-off valve 43 is supplied with compressed air into the cylinder chamber 68 as shown in FIG.
The diaphragm 62 moves upward (valve opening direction) against the spring force of the coil spring 66. As a result, the diaphragm 62 separates from the valve seat 60 and the fluid flowing from the inflow-side flow passage 71 flows out to the outflow-side flow passage 73 to flow-rate stabilizing portion 44.
Is supplied to.

At this time, in the flow rate stabilizing portion 44, as shown in FIG. 5, since compressed air is supplied to the cylinder chamber 88, the piston 84 moves downward against the spring force of the coil spring 86. . Therefore, the diaphragm 82 is close to the valve seat 80, but is sufficiently separated from the valve seat 80. Therefore, the fluid that has flowed in from the inflow-side flow passage 91 flows out to the outflow-side flow passage 93 with a constant flow rate and is supplied to the mixing nozzle 16.

Next, in S20, it is checked whether the integrated flow rate value of the mass flow meter 27 has reached a preset value set in the control circuit 40. In S20, when the integrated flow rate value of the mass flow meter 27 is less than or equal to the preset value set in the control circuit 40, the process of S19 is repeated to continue the nitrogen gas supply to the storage tank 22.

Further, in S20, when the integrated flow rate value of the mass flow meter 27 reaches the preset value set in the control circuit 40, the process proceeds to S21, and the fluid (pure water) having a lower mixing ratio is supplied. The flow rate adjusting valve 30 and the opening / closing valve 43 for the above are first closed (see FIG. 3) to stop the supply of the nitrogen gas and stop the supply of the chemical liquid to the mixing nozzle 16.

That is, in the on-off valve 43, as shown in FIG. 3, the supply of compressed air to the cylinder chamber 68 is stopped, so that the diaphragm 62 moves downward (valve closing direction) by the spring force of the coil spring 66. Moving. As a result, the diaphragm 62 abuts the valve seat 60 and blocks the inflow side flow passage 71 and the outflow side flow passage 73 from each other.

At the same time, the supply of compressed air to the flow rate stabilizing section 44 is stopped. Therefore, in the flow rate stabilizing unit 44, when compressed air is no longer supplied to the cylinder chamber 88 as shown in FIG. 6, the diaphragm 82 receives the spring force of the coil spring 86 from the valve seat 80 via the piston 84. Displaces upward in the direction of separation.

That is, the flow rate stabilizing unit 44 is provided with the opening / closing valve 43.
Simultaneously with the valve closing operation, the volume of the flow path formed between the diaphragm 82 and the valve seat 80 is expanded. Therefore, the flow rate stabilizing unit 44 absorbs a temporary increase in the flow rate due to the closing operation of the opening / closing valve 43 by the diaphragm 82 moving upward, and stabilizes the flow rate flowing into the mixing nozzle 16.

Thereafter, in S22, the flow rate adjusting valve 50 of the pure water supply conduit 45 for supplying the fluid (pure water) having the higher mixing ratio.
Is closed to stop the pure water supply to the mixing nozzle 16.

At the next step S23, if the power switch is on, the process returns to step S12 and the processes at and after S12 are repeated. That is, a predetermined amount of the chemical liquid is injected into the storage tank 22 and the input of a supply request signal from the host device is waited for. When the supply request signal is input, the above S16
Liquids mixed at a constant ratio in the processing procedure of to S22 are discharged from the mixing nozzle 16.

As described above, in this embodiment, the flow rate adjusting valve 3
When 0 is closed to stop the supply of nitrogen gas, the supply of compressed air to the opening / closing valve 43 is stopped at the same time, and the supply of the chemical liquid to the mixing nozzle 16 is stopped. At that time, the flow rate stabilizing unit 4
The diaphragm 4 expands the volume of the flow path formed between the diaphragm 8 and the valve seat 80 by the upward movement of the diaphragm 82.
By moving 2 upward, the temporary increase in the flow rate due to the closing operation of the opening / closing valve 43 is absorbed, and the flow rate flowing into the mixing nozzle 16 is stabilized.

Therefore, the mixed liquid mixed by the mixing nozzle 16 is supplied at a constant concentration without being affected by the change in the flow rate due to the closing operation of the opening / closing valve 43.

In the present embodiment, the apparatus configured to mix the two kinds of fluids by the mixing nozzle 16 is given as an example, but the present invention is not limited to this, and for example, the two kinds of fluids are mixed in the tank. However, it goes without saying that the present invention can be applied to a mixing device configured to be stirred and supplied.

Further, in the present embodiment, the construction in which the diaphragms 62 and 82 are used as the valve bodies in the on-off valve 43 and the flow rate stabilizing portion 44 is given as an example, but the present invention is not limited to this, and, for example, supply of compressed air Any configuration may be used as long as it has a pressure receiving portion that operates when stopped.

In the present embodiment, the case where hydrofluoric acid and pure water are mixed at a predetermined ratio has been described as an example, but the present invention can be applied to the case of mixing other chemicals. Of course.

In this embodiment, the case where two kinds of liquids of hydrofluoric acid and pure water are mixed has been described as an example, but the present invention is also applicable to the case of mixing two or more kinds of fluids having different components. Of course, the invention can be applied.

[0067]

As described above, according to the first aspect of the invention, a plurality of fluid supply paths for individually supplying different kinds of fluids and a plurality of on-off valves arranged for each of the plurality of fluid supply paths are provided. In a mixing device including a mixing path in which the downstream ends of a plurality of fluid supply paths merge and a plurality of kinds of fluids are mixed and supplied, an increase in the flow rate due to the closing operation of the on-off valve is absorbed. Since the flow rate stabilizing means for keeping the supply amount to the mixing path constant is provided downstream of the on-off valve, the fluid supply amount is prevented from fluctuating due to the closing operation of the on-off valve and the concentration of the mixed fluid is controlled. Can be stabilized.

Further, according to the second aspect of the invention, since the opening / closing valve is opened by the displacement of the valve portion by the supply of the compressed air, a certain amount of fluid corresponding to the area of the valve portion is introduced into the flow passage. The concentration of the mixed fluid can be stabilized by preventing it from being pushed out.

According to the third aspect of the invention, the flow rate stabilizing means receives the pressure so as to absorb the increase in the flow rate due to the closing operation of the opening / closing valve when the supply of the compressed air to the opening / closing valve is stopped. Since the flow rate adjusting unit that operates the unit is provided, it is possible to prevent a constant amount of fluid corresponding to the area of the valve unit of the on-off valve from being pushed out into the flow path and stabilize the concentration of the mixed fluid.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of an embodiment of a mixing apparatus according to the present invention.

FIG. 2 is a vertical cross-sectional view showing an enlarged configuration of a mixing nozzle 16.

FIG. 3 is a vertical sectional view showing a closed state of an opening / closing valve 43.

FIG. 4 is a vertical sectional view showing an open state of an opening / closing valve 43.

5 is a vertical cross-sectional view showing the structure of a flow rate stabilizing unit 44. FIG.

FIG. 6 is a vertical sectional view showing a flow rate adjusting operation of the flow rate stabilizing unit 44.

FIG. 7 is a flowchart showing a control process executed by a control circuit 40.

[Explanation of symbols]

10 Mixing device 12 Chemical supply route 14 Pure water supply route 16 mixing nozzle 18 Chemical supply line 20 Nitrogen gas supply line 22 Storage tank 24 Chemical discharge line 27 mass flow meter 30 Flow control valve 34,43 open / close valve 30a, 34a, 43a, 44a Air line 32 Ultrasonic vortex flowmeter 37 Relief valve 38 Pressure sensor 39 Air supply circuit 40 control circuit 41 Air source 44 Flow Stabilizer 45 Pure water supply line 46 Temperature control unit 48 flow meter 50 Flow control valve 52 Nozzle body 54 nozzle flow path 56 needle pipe 58,78 housing 60,80 valve seat 62,82 diaphragm 64,86 pistons 66,86 coil spring 68,88 Cylinder chamber 70,90 Air inlet 71, 91 Inflow side flow path 73, 93 Outflow side flow path 74,94 diaphragm chamber 96 adjustment bolt

Claims (3)

[Claims] 1. A plurality of fluid supply paths for individually supplying different kinds of fluids, a plurality of on-off valves arranged for each of the plurality of fluid supply paths, and a downstream end portion of the plurality of fluid supply paths join together. However, in a mixing device including a mixing path for mixing and supplying the plurality of types of fluids, an increase in the flow rate due to the valve closing operation of the on-off valve is absorbed to reduce the supply amount to the mixing path. A mixing device, characterized in that a flow rate stabilizing means for keeping constant is provided downstream of the on-off valve. 2. The mixing device according to claim 1, wherein the on-off valve opens when the valve portion is displaced by the supply of air. 3. The flow rate stabilizing means has a flow rate adjusting section for operating the pressure receiving section so as to absorb an increase in the flow rate due to the closing operation of the opening / closing valve when the air supply to the opening / closing valve is stopped. The mixing device according to claim 2, wherein