JP3764280B2 - Chemical supply system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to, for example, a chemical solution supply system that is provided at a relay point where a chemical solution stored in a tank or the like is pumped to a discharge destination and includes a pair of bellows pumps for continuously supplying the liquid. The present invention relates to a chemical supply system that can eliminate dissolved gas in a chemical solution by foaming the bellows.
[0002]
[Prior art]
A clean room where semiconductors are manufactured is usually built on the second floor or higher of the building. Therefore, a chemical solution such as a resist solution used in the semiconductor manufacturing process is stored, for example, in an external tank of a factory, and a line is drawn from the tank and supplied to a clean room. At this time, a pressure feeding means for pushing up the chemical liquid from the bottom to the top is necessary, and FIG. 8 is a block diagram showing a conventional chemical liquid pressure feeding means.
[0003]
In this case, two tanks 51 and 61 are provided, and the chemical solution once supplied in the tank is pressurized with an inert gas and is pumped to the clean room on the upper floor.
Therefore, the tanks 51 and 61 are piped to a chemical tank outside the factory via valves 52 and 62, while the tanks are piped to the clean room via valves 53 and 63. Further, in order to supply an inert gas for pressurizing the chemical solution filled in the tanks 51 and 61, a pressurizing line through valves 54 and 64 is provided. Further, in order to remove bubbles in the tanks 51 and 61, piping is provided to the atmosphere side via valves 55 and 65.
[0004]
When the valves 52 and 62 are opened and closed and the tanks 51 and 61 are filled with the chemical solution, the valves 54 and 64 are opened to supply the inert gas and pressurize the chemical solution. In the initial stage of pressurization, the valves 55 and 65 are opened and closed to discharge bubbles in the chemical solution, and subsequently, the valves 53 and 63 are opened to feed the chemical solution to the clean room. Thereafter, the valves 55 and 65 are closed simultaneously with the valves 54 and 64, and the supply of the chemical liquid is completed.
Such a chemical supply operation is not performed simultaneously in the tanks 51 and 61 but is performed alternately.
[0005]
However, in the conventional product, since the chemical solution is directly pressurized with the inert gas, the inert gas dissolves in the chemical solution and foams in the secondary pipe, causing defects in the product manufactured by the bubbles. was there.
Further, by directly pressurizing the chemical solution with the inert gas, the chemical solution may be reversely diffused in the gas supply line for supplying the inert gas, and the pipe may be corroded. In order to cope with this, it is necessary to use expensive piping such as stainless steel and Teflon.
[0006]
In order to solve these problems, a method of pressurizing an inert gas and a chemical solution by separating them with a diaphragm can be considered. However, even when the diaphragm is used, there still remains a problem that the inert gas already melted in the chemical solution is foamed.
As a method of removing the inert gas that has already melted from the chemical solution, the applicant of the present invention in Japanese Patent Publication No. 7-45001 discloses that the pressure applied to the diaphragm is a negative pressure and the pressure applied to the chemical solution is a negative pressure. Proposed and patented for degassing the dissolved gas.
[0007]
[Problems to be solved by the invention]
However, the method proposed by the present applicant in Japanese Patent Publication No. 7-45001 has the following problems.
(1) A phenomenon has been found in which foaming increases rapidly when the pressure is lowered to increase the efficiency of defoaming. That is, for example, when ethyl alcohol is used as a chemical solution, it has been found that foaming increases rapidly at a pressure of 10.4 KPa or less at a room temperature of 20 degrees Celsius. This is because the room temperature is 20 degrees Celsius and 10.4 KPa is the boiling point of ethyl alcohol.
In the method of the conventional Japanese Examined Patent Publication No. 7-45001, this was not noticed, so the chemical liquid was discharged by reducing the negative pressure too much until the chemical liquid became the boiling point or less, so the chemical liquid was wasted. There was a problem.
[0008]
(2) The diaphragm pump has a problem that the negative pressure cannot be finely controlled because a large amount of chemical liquid is discharged by a slight movement of the diaphragm. In addition, there is a problem that it is difficult to carry out a certain amount of chemical solution with high accuracy because the diaphragm, movement, and discharge amount of the chemical solution are not in a linear relationship.
(3) Further, the method disclosed in Japanese Patent Publication No. 7-45001 has a problem that foaming cannot be sufficiently generated because a normal orifice is used as the foaming means.
[0009]
Therefore, the present invention eliminates such problems and provides a chemical solution supply system capable of removing the inert gas melted in the chemical solution by foaming and pressurizing the chemical solution and carrying it out with a certain amount of accuracy. Objective.
[0010]
[Means for Solving the Problems]
The chemical solution supply system of the present invention has the following configuration.
(1) (a) A bellows having a variable volume, which expands its volume to draw a chemical into the bellows, and reduces the bellows volume to reduce the bellows from the discharge port. A bellows having a structure for discharging the chemical solution to the outside, (b) a bellows tank for storing the bellows, and (c) provided in the suction port, when the chemical solution is sucked into the bellows from the suction port A foaming means for foaming the gas dissolved in the chemical solution and (d) a discharge port provided separately from the discharge port, before the chemical solution is discharged out of the bellows from the discharge port, A bellows pump having a bubble removal port for removing outside is provided, and (e) the bellows is contracted by pressurizing the inside of the bellows tank, While discharging the chemical solution from the outlet to the outside of the bellows, The bellows tank is inflated by applying a vacuum pressure inside the bellows tank, Foaming means for inhaling medicinal solution from the suction port into the bellows, when the suction port is opened, the bellows tank is inflated by applying a vacuum pressure, and the medicinal solution is sucked into the bellows The first defoaming step of foaming the gas dissolved in the chemical solution sucked from the suction port into the bellows tank, and the vacuum pressure in the bellows tank in the state where the suction port, the discharge port, and the bubble removal port are closed Higher than the defoaming process By maintaining the vacuum pressure in the bellows tank at a vacuum pressure slightly closer to the atmospheric pressure than the boiling point of the chemical solution, The bellows is expanded from the first defoaming step, By maintaining the pressure inside the bellows at a vacuum pressure slightly closer to the atmospheric pressure than the boiling point of the chemical, gas Foam Second defoaming step And a bellows control device.
For example, when ethyl alcohol is used as the chemical solution, the boiling point of ethyl alcohol is 10.4 KPa at room temperature of 20 degrees Celsius, so the vacuum pressure is maintained at about 13 KPa to 20 KPa, which is slightly closer to atmospheric pressure.
[0011]
(2) Further, in the chemical liquid supply system described in (1), the chemical liquid bellows pump and the bellows control device each have a pair, and the bellows control device switches the pair of chemical liquid bellows pumps. Thus, a constant pressure chemical solution is always supplied.
(3) In the chemical liquid supply system described in (1) or (2), the foaming means is a cavitation nozzle, and the cavitation nozzle includes two or more right-angle flow paths formed at right angles, and the chemical liquid is In the chemical solution by colliding with the channel wall in the right-angle channel gas It is characterized by foaming.
Here, the configuration of the cavitation nozzle is preferably provided with a baffle plate in the vicinity of the outlet of the right-angle channel so that the chemical solution exiting the right-angle channel collides with the baffle plate.
[0012]
Next, the operation of the chemical solution supply system having the above configuration will be described.
The bellows control device contracts the bellows by pressurizing the inside of the bellows tank, and carries out the chemical solution in the bellows. In addition, the bellows tank is inflated by setting the inside of the bellows tank to a vacuum pressure, and the pressure in the bellows is maintained at a vacuum pressure slightly closer to the atmospheric pressure than the boiling point of the chemical liquid in the expanded state of the bellows. Let the dissolved gas foam. Here, since the pressure in the bellows is maintained at a vacuum pressure that is a little closer to the atmospheric pressure than the boiling point with the bellows expanded, the chemical solution does not boil and foam, so the chemical solution is discharged wastefully. There is nothing to do. Moreover, in the state which does not boil, since it is the state which is most easily foamed, the inert gas which melt | dissolved in the chemical | medical solution can be foamed to the maximum.
[0013]
Moreover, according to the chemical solution supply system of the present invention, the chemical solution is alternately carried out from the two bellows pumps. At this time, the pressure of the working fluid for pushing out the chemical solution is passed through the bellows in the bellows tank. Since the working fluid does not directly contact the chemical liquid filled in the bellows, the gas used as the working fluid does not dissolve in the chemical liquid. Further, since the bellows has a linear relationship between the moving distance of the bellows and the amount of the chemical solution carried out as compared with the diaphragm, the amount of the chemical solution supplied per certain time can always be kept constant.
[0014]
In addition, since the direction of fluid does not change at the orifice, the foaming efficiency is poor.However, in a cavitation nozzle equipped with a right-angle channel, the chemical solution is ejected after colliding with the wall of the right-angle channel. More molten gas can be degassed. Furthermore, by providing a baffle plate at the outlet of the right-angle channel and causing the chemical solution to collide with the baffle plate again, the foaming efficiency can be further increased, and more of the molten gas in the chemical solution can be degassed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a chemical solution supply system according to the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing the overall configuration of the chemical liquid supply system of the present embodiment, and FIGS. 2 and 3 are cross-sectional views showing the configuration of a bellows pump used in the system.
First, the configuration of the bellows pump will be described with reference to FIGS.
In this embodiment, a bellows pump, which is a chemical pump for supplying a chemical solution such as an organic solvent, a photoresist, and a developing solution in a chemical treatment process of semiconductor manufacturing, will be described.
Since the required processing dimensions of semiconductor products are extremely miniaturized, impurities such as gas and foreign matter mixed in the chemical solution supplied to the chemical treatment process will cause shape defects and defective properties in semiconductor products. There is a fear that it is not preferable. Therefore, a chemical pump that can remove impurities such as gas in advance from the chemical and supply only a clean chemical to the chemical treatment process is used.
[0016]
The bellows pump 11 expands the volume of the bellows 12 formed to have a variable volume, sucks the chemical into the bellows 12 from the suction port 24, and reduces the volume of the bellows 12 to reduce the bellows 12 from the discharge port 25. It has a structure in which the chemical liquid is discharged out of the rose 12. FIG. 3 shows a state where the volume of the bellows 12 is reduced most, and FIG. 2 shows a state where the volume of the bellows 12 is expanded most.
The bellows 12 is accommodated in a casing 23 that is a bellows tank. The upper end of the bellows 12 is fixed and sealed to the upper part of the casing 23, and the lower end is closed by a bottom plate 32. A space between the casing 23 and the bellows 12 is a back chamber 33 of the bellows pump 11. By introducing a negative pressure into the back chamber 33, the bellows 12 expands and the volume in the bellows 12 expands. By introducing positive pressure into the back chamber 33, the bellows 12 contracts and the volume in the bellows 12 decreases. In this embodiment, a pressure line for introducing positive pressure and negative pressure into the back chamber 33 is connected to the back chamber 33. Outside the casing 23, magnetic sensors 29 and 30 for detecting the magnet 32 and confirming the state of the bellows 12 are movably attached to the sensor mounting rod 31.
[0017]
The suction port 24 is provided with a cavitation nozzle 27. The cavitation nozzle 27 is for degassing a gas such as an inert gas dissolved in the chemical solution when the chemical solution is sucked into the bellows 12 from the suction port 24.
The configuration of the cavitation nozzle 27 is shown in FIG. The cavitation nozzle 27 is composed of a right-angle channel 27a having four outlet channels 27d opened in four directions from the bottom of the center hole, and a baffle plate 27b provided with a small gap 27C from the outlet channel 27d. Has been.
[0018]
The chemical solution collides with the bottom surface in the right-angle channel 27a, thereby causing a sudden pressure change to generate cavitation and foam. Furthermore, when it collides with the baffle plate 27b in the outlet flow path 27d, a sudden pressure change is generated to generate cavitation and foam.
Here, as shown in FIG. 5, a cavitation nozzle 27 without a baffle plate may be used. In the case of FIG. 5, although the foaming efficiency is deteriorated, there is an advantage that the space can be reduced.
The bellows pump 11 includes a bubble removal port 26 provided separately from the discharge port 25. The bubble removal port 26 is for removing the defoamed bubbles (including impurities such as foreign matters) out of the bellows 12 before the chemical liquid is discharged out of the bellows 12 from the discharge port 25. An outlet conduit for leading out the bubbles from the bubble removal port 26 is connected to the bubble removal port 26.
[0019]
The bellows pump 11 has a bubble separation tube 28 attached to the discharge port 25. The bubble separation tube 28 is disposed so as to protrude into the bellows 11 from the discharge port 25. The bubble separation tube 28 has a plurality of liquid introduction holes 28b for introducing only the chemical liquid in order to separate the bubbles from the chemical liquid discharged from the discharge port 25. The liquid bubble separation tube 28 extends vertically downward from the discharge port 25, and its lower end is closed. In the vicinity of the lower end portion, each circular liquid introduction hole 28b is opened in the horizontal direction. The liquid bubble separation tube 28 has an umbrella portion 28a that extends outward just below each liquid introduction hole 28b at the lower end thereof. A lead-out conduit for leading the chemical solution from the discharge port 25 is connected to the discharge port 25.
[0020]
Next, the overall configuration of the chemical solution supply system will be described with reference to FIG.
A bellows pump 11A and a bellows pump 11B are arranged in parallel. Discharge opening / closing valves 14A and 14B are connected to the discharge ports 25A and 25B of the bellows pumps 11A and 11B. The discharge on / off valves 14A and 14B are connected to a semiconductor process line. Suction opening / closing valves 13A and 13B are connected to the suction ports 24A and 24B of the bellows pumps 11A and 11B. The suction opening / closing valves 13A and 13B are connected to the same chemical solution tank.
Bubble removal opening / closing valves 15A and 15B are connected to the bubble removal ports 26A and 26B of the bellows pumps 11A and 11B. The bubble removal opening / closing valves 15A and 15B are connected to the exhaust passage.
[0021]
Further, the working gas supply opening / closing valve 16 and the working gas exhaust opening / closing valve 17 are connected to the back chambers 33A, 33B of the bellows pumps 11A, 11B via pressure lines. The working gas supply on / off valves 16A and 16B are connected to a nitrogen gas supply source which is a working gas via a check valve 18, a pressure gauge 19 and a regulator 20. Further, the working gas exhaust on-off valves 17A and 17B are connected to the ejector 22. The ejector 22 is connected to a working air source via an ejector valve 21. Further, the exhaust of the ejector 22 is connected to the exhaust passage.
[0022]
Next, the operation of the chemical solution supply system configured as described above will be described.
First, the operation of the bellows pump 11 will be described. FIG. 7 is a timing chart showing the operation of the two bellows pumps 11A and 11B.
In order to inhale the chemical into the bellows 12, in the state shown in FIG. 3, the suction on / off valve 13 corresponding to the suction port 24 is opened, and the discharge on / off valve 14 and bubble removal corresponding to the discharge port 25 and the bubble removal port 26 are removed. The on-off valve 15 is closed. Then, the working gas exhaust opening / closing valve 17 is opened and a negative pressure is introduced into the back chamber 33 using the ejector 22. As a result, the bellows 12 expands toward the state shown in FIG. 2 and the volume in the bellows 12 expands, and along with this, the chemical solution is sucked into the bellows 12 through the suction port 24. At this time, the chemical liquid sucked into the bellows 12 is subjected to a pressure change by a cavitation nozzle 27 provided at the suction port 24, so that impurities such as gas and foreign matter dissolved in the chemical liquid are first defoamed. It is received and bubbled.
[0023]
Then, a second amount of defoaming is performed in a state where a predetermined amount of the chemical solution is inhaled into the bellows 12 and bubbles are accumulated by the first defoaming. Therefore, by closing the on-off valves 13, 14, 15 corresponding to the suction port 24, the discharge port 25, and the bubble removal port 26, and further introducing negative pressure into the back chamber 33, the volume in the bellows 12 is further increased. It is expanded to make the inside of the bellows 12 have a negative pressure. Thereby, the chemical | medical solution in the bellows 12 will be exposed to a negative pressure, the chemical | medical solution in the bellows defoamed by the cavitation nozzle 27 will be further defoamed, and the gas etc. which were dissolved in the chemical | medical solution will be bubbled. .
[0024]
That is, for example, when ethyl alcohol is used as the chemical solution, FIG. 6 shows the relationship between the vacuum pressure, which is a negative pressure at 20 degrees Celsius, and the degree of foaming.
Since the boiling point of ethyl alcohol is 10.4 Kpa, severe foaming occurs as shown by S2 in the figure when the pressure is 10.4 KPa or less. This foaming is for foaming ethyl alcohol. When ethyl alcohol is gasified and discharged from the bubble removal port 26, ethyl alcohol, which is a chemical solution, is wasted. As shown by S1 in the figure, an unillustrated bellows control device gasifies ethyl alcohol by maintaining a vacuum pressure at 13 KPa to 20 KPa, which is slightly closer to the atmospheric pressure than the boiling point. do not do It is possible to foam most of the inert gas melted in the range. The degree of foaming on the vertical axis indicates the ratio when the foaming at the boiling point is 100.
[0025]
Thereafter, the bubble removal opening / closing valve 15 corresponding to the bubble removal port 26 is opened, the working gas exhaust valve 17 is closed, and the working gas supply valve 16 is opened to introduce a positive pressure into the back chamber 33. As a result, the bellows 12 contracts toward the state shown in FIG. 3, the volume in the bellows 12 is reduced, and bubbles accumulated in the bellows 12 are discharged from the bubble removal port 26 to the outside of the bellows 12 through the outlet conduit. Removed.
[0026]
Thereafter, the bubble removal opening / closing valve 15 corresponding to the bubble removal port 26 is closed, the discharge opening / closing valve 14 corresponding to the discharge port 25 is opened, and a positive pressure is further introduced into the back chamber 33, whereby the volume in the bellows 12 is increased. Is further reduced, and the chemical solution is discharged from the discharge port 25 to the outside of the bellows 12 through the outlet conduit. Here, a liquid bubble separation tube 28 is provided at the discharge port 25, and only the chemical liquid is supplied from the liquid introduction hole 28b. liquid Bubbles are separated from the chemical liquid introduced into the bubble separation tube 28 and discharged from the discharge port 25.
[0027]
Accordingly, even if bubbles are gathered around the discharge port 25 or bubbles that cannot be removed because a large amount of bubbles are generated at the time of defoaming, the bubbles remain in the bellows 12. It does not get mixed in the chemicals discharged from. Therefore, impurities such as gas and foreign matter in the chemical solution can be removed, and bubbles can be reliably removed from the chemical solution discharged from the discharge port 25. As a result, only a clean chemical solution that does not contain any impurities such as gas can be supplied to the chemical treatment process apparatus.
[0028]
In particular, in this embodiment, the lower end of the liquid bubble separating tube 28 is closed, and the liquid introduction hole 28b is opened in the horizontal direction. Also, the bubbles in the liquid usually have the property of rising upwards according to their buoyancy. Accordingly, it is difficult for the air bubbles that are about to float inside the bellows 12 to enter the liquid introduction holes 28b. In this sense, the bubbles can be reliably removed from the chemical liquid discharged from the discharge port 25.
Furthermore, according to this embodiment, the liquid bubble separation tube 28 is provided with the umbrella portion 28a that extends outward just below each liquid introduction hole 28b. Accordingly, the bubbles that are about to float inside the bellows 12 by the buoyancy are blocked by the umbrella portion 28a, and the bubbles are more difficult to enter the liquid introduction holes 28b. In this sense, air bubbles can be more reliably removed from the chemical liquid discharged from the discharge port 25 than when the umbrella portion 28a is not provided.
[0029]
In the bellows pump 11 of this embodiment, since the volume in the bellows 12 is expanded and contracted by expanding and contracting the bellows 12, the volume change in the bellows 12 is made relatively large. Is possible. For this reason, the suction and discharge of the chemical liquid and the defoaming and discharge of the chemical liquid can be performed without excess or deficiency in one suction / discharge process. Further, unlike the diaphragm, the change in the bellows 12 has a linear relationship with the amount of the discharged chemical, so that the amount of the chemical can be accurately controlled at a certain rate.
[0030]
Next, the operation of the entire chemical supply system having the above configuration will be described.
The two bellows pumps 11A and 11B and the operation timing are shown in a timing chart in FIG.
As shown in FIG. 7, the two bellows pumps 11A and 11B are operated alternately. According to the chemical liquid supply system of the present embodiment, the chemical liquid is alternately carried out from the two bellows pumps 11A and 11b. At this time, the pressure of the working fluid for pushing out the chemical liquid is within the bellows tank 11. Since the working fluid does not directly contact the chemical liquid filled in the bellows 12 that acts via the rose 12, the gas used as the working fluid does not dissolve in the chemical liquid.
[0031]
According to the chemical solution supply system of the present embodiment, the bellows 12A and 12B are formed with a variable volume, and by inflating the volume, the chemical solution is sucked into the bellows 12A and 12B from the suction ports 24A and 24B. The bellows 12A, 12B having a structure for discharging the chemical solution from the discharge ports 25a, 25B to the outside of the bellows 12A, 12b by reducing the volume of the bellows 12A, 12B, and the bellows for storing the bellows 12A, 12B Cavitation nozzle 27A provided in tanks 23A and 23B and suction ports 24A and 24B for foaming the gas dissolved in the chemicals when suctioned from the suction ports 24A and 24B into the bellows 12A and 12b. 27B and the discharge ports 24A and 24B are provided separately from the discharge ports 24A and 24B. A bellows pumps 11A and 11B having bubble removal ports 26A and 26B for removing the defoamed bubbles to the outside of the bellows 12A and 12B before discharging the chemical solution outside the A and 12B, and the back chamber The bellows 12A and 12B are contracted by pressurizing 33A and 33B, the bellows 12A and 12B are expanded by making the back chambers 33A and 33B vacuum, and the bellows 12A and 12B are expanded. Since it has a bellows control device that foams the dissolved gas in the chemical liquid by maintaining the pressure in 12A and 12B at a vacuum pressure that is slightly closer to the atmospheric pressure than the boiling point of the chemical liquid, the chemical liquid boils and foams. Since there is no such thing, the chemical solution is not wasted. Moreover, in the state which does not boil, since it is the state which is most easily foamed, the inert gas which melt | dissolved in the chemical | medical solution can be foamed to the maximum.
[0032]
In addition, according to the chemical solution supply system of the present embodiment, each of the bellows pump 11 and the bellows control device has a pair, and the bellows control device switches between the pair of bellows pumps 11A and 11B, so that it is always constant. Since the chemical liquid of the pressure is supplied, the pressure of the working fluid for pushing out the chemical liquid acts through the bellows 12A and 12B, and the working fluid does not directly contact the chemical liquid filled in the bellows 12A and 12B. The gas used as the working fluid does not dissolve in the chemical solution. In addition, the bellows 12A and 12B have a linear relationship between the moving distance of the bellows 12A and 12B and the amount of discharged chemical compared to the diaphragm, so that the amount of chemical supplied per fixed time is always maintained constant. be able to
[0033]
Further, according to the chemical solution supply system of the present embodiment, the cavitation nozzle 27 includes two or more right-angle channels 27a formed at right angles, and the drug solution collides with the channel walls in the right-angle channels 27a. Since the dissolved gas in the chemical liquid is foamed, the direction of the fluid does not change at the orifice, so the foaming efficiency is poor. However, in the cavitation nozzle 27 provided with the right-angle flow path 27a, the chemical liquid is ejected after colliding with the wall of the right-angle flow path 27a. As a result, the foaming efficiency can be improved and the molten gas in the chemical solution can be degassed more. Furthermore, by providing a baffle plate 27b at the outlet of the right-angle channel 27a and causing the chemical liquid to collide with the baffle plate 27b again, the foaming efficiency can be further increased, and more of the molten gas in the chemical liquid can be degassed.
[0034]
In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change is possible in the range which does not deviate from the meaning.
For example, in the above embodiment, a pair of bellows pumps is used, but three or more bellows pumps including a spare may be provided.
[0035]
【The invention's effect】
According to the chemical solution supply system of the present invention, the bellows is contracted by pressurizing the back chamber of the bellows pump, and the bellows is expanded by applying a vacuum pressure to the back chamber, and the bellows is expanded. Since the pressure inside the rose is controlled to make the dissolved gas in the chemical liquid foam by maintaining a vacuum pressure slightly closer to the atmospheric pressure than the boiling point of the chemical liquid, the chemical liquid will not boil and foam. Will not be wasted. Moreover, in the state which does not boil, since it is the state which is most easily foamed, the inert gas which melt | dissolved in the chemical | medical solution can be foamed to the maximum.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an overall configuration of a chemical liquid supply system according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing an expanded state of the diaphragm pump 11;
3 is a cross-sectional view showing a contracted state of the diaphragm pump 11. FIG.
4 is a cross-sectional view of the cavitation nozzle 27. FIG.
FIG. 5 is a sectional view of a cavitation nozzle 27 according to another embodiment.
FIG. 6 is a data diagram showing the vacuum pressure and the degree of foaming.
FIG. 7 is a timing chart.
FIG. 8 is a system diagram showing a configuration of a conventional chemical solution supply system.
[Explanation of symbols]
11A, 11B Bellows pump
12A, 12B Bellows
24 Suction port
25 Discharge port
26 Bubble removal port
27 Cavitation nozzle
28 Liquid bubble separator
33 Back room

Claims (3)

A bellows with a variable volume, which expands its volume to draw chemicals into the bellows, and reduces the bellows volume to discharge the chemicals from the discharge port to the outside of the bellows. A bellows with a structure to allow
A bellows tank for storing the bellows;
A foaming means provided in the suction port for foaming the gas dissolved in the chemical solution when the chemical solution is sucked into the bellows from the suction port;
A bellows provided separately from the discharge port and having a bubble removal port for removing the defoamed bubbles out of the bellows before discharging the chemical liquid from the discharge port to the outside of the bellows. With a pump,
Wherein deflating the bellows by pressurizing bellows tank while discharging the chemical solution to said bellows outer from the discharge port, the bellows is expanded by the vacuum pressure of the bellows tank, wherein Inhaling the medicinal solution into the bellows from an inlet,
The bellows tank is inflated by making the inside of the bellows tank a vacuum pressure with the suction port open, and when the chemical solution is sucked into the bellows, the foaming means causes the suction port to enter the bellows tank. A first defoaming step of foaming the gas dissolved in the chemical solution sucked into the
With the suction port, the discharge port, and the bubble removal port closed, the vacuum pressure in the bellows tank is made higher than that in the first defoaming step so that the vacuum pressure in the bellows tank is slightly lower than the boiling point of the chemical solution. by maintaining the vacuum pressure close to atmospheric pressure, the bellows is expanded from the first degassing step, by maintaining the pressure before Symbol base in Rose vacuum pressure close to slightly atmospheric pressure boiling point of the chemical chemical supply system, comprising a bellows controller for a second degassing step Ru by foaming gas in said chemical solution. In the chemical solution supply system according to claim 1,
Each of the chemical liquid bellows pump and the bellows control device has a pair,
The chemical liquid supply system, wherein the bellows control device always supplies a chemical liquid at a constant pressure by switching the pair of chemical liquid bellows pumps. In the chemical solution supply system according to claim 1 or 2,
The foaming means is a cavitation nozzle, and the cavitation nozzle comprises two or more right-angle flow paths formed at right angles;
The chemical solution supply system according to claim 1, wherein the chemical solution foams a gas in the chemical solution by colliding with a channel wall in the right-angle channel.

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