JP4872613B2 - Gas dissolving cleaning water manufacturing apparatus and manufacturing method - Google Patents

Description

  The present invention relates to a manufacturing apparatus and a manufacturing method for gas-dissolved cleaning water. More specifically, the present invention relates to a gas-dissolved cleaning water in which a specific gas used for cleaning electronic parts such as silicon wafers for semiconductors and glass substrates for flat panel displays that require high cleanliness is dissolved at a predetermined concentration. The present invention relates to an apparatus and a method for producing dissolved gas cleaning water that can reduce the amount of a specific gas to be used, and can supply the gas efficiently, stably and safely.

  Conventionally, wet cleaning called RCA cleaning has been the mainstream for cleaning substrates serving as electronic components. For RCA cleaning, a mixed solution of sulfuric acid and hydrogen peroxide solution (SPM) is heated to 120 to 150 ° C, or a mixed solution of ammonia and hydrogen peroxide solution (APM) is heated to 60 to 80 ° C. This is a cleaning method in which a mixed liquid (HPM) of hydrochloric acid and hydrogen peroxide water is heated to 60 to 80 ° C. and used. When this cleaning method is used, the high cost of high concentration chemicals and cleaning agents, the voluminous amount of pure water and ultrapure water used to rinse them, the chemical vapor is exhausted, and new clean air is prepared. Various simplification efforts have been made and achieved results in order to reduce air-conditioning costs and the like, as well as to reduce environmental burdens such as mass use of water, mass disposal of chemicals, and emission of exhaust gas. A typical example is an ultrasonic cleaning technique using cleaning water in which a specific gas such as hydrogen is dissolved.

  The key point of this new cleaning technique is to dissolve a specific gas at a high concentration. Furthermore, in order to stably maintain a high cleaning effect, it is necessary to control the dissolved gas concentration to a high concentration and below the saturation concentration at the place of use. In addition, when hydrogen is dissolved to a saturation concentration or higher, there is an increased risk that dissolved hydrogen will be bubbled and stay in the system at atmospheric pressure. In order to save water in a cleaning process that requires a large amount of gas-dissolved cleaning water, it is required to circulate and use the cleaning waste water. It is desirable to construct a circulation system by removing foreign substances in the washing wastewater and adjusting the dissolved gas concentration. In response to such technical needs, gas (mainly nitrogen) dissolved in pure water or ultrapure water, which is raw water, is removed by degassing treatment, and then the gas to be dissolved is supplied in an amount equal to or lower than the saturated concentration. The technology to do this has been developed by the present inventors. The usefulness of this method has been recognized and has become widespread as a new technology for wet cleaning.

  For example, it is possible to supply hydrogen-containing ultrapure water having a stable dissolved hydrogen concentration to a use point even when the amount of water used is fluctuated without causing surplus generation and disposal of hydrogen-containing ultrapure water for cleaning. As a hydrogen-containing ultrapure water supply device, in the cleaning process of electronic materials using hydrogen-containing ultrapure water, it retains a mixture of excess hydrogen-containing ultrapure water that was not used at the point of use and ultrapure water to be replenished A sealed water tank, a pump for feeding water held in the water tank, a degassing part for removing dissolved gas from the water being sent, and a dissolving part for dissolving hydrogen supplied from the hydrogen supply part in the degassed water A supply device for hydrogen-containing ultrapure water that has a circulation pipe that returns to the water tank through a filter and a use point, and supplies the required amount of hydrogen-containing ultrapure water at the use point while circulating the hydrogen-containing ultrapure water has been proposed. The That (Patent Document 1).

  According to this apparatus, it is possible to efficiently produce gas-dissolved cleaning water in which a specific gas having a high concentration and a saturation concentration or less is dissolved. However, this apparatus always requires a degassing step for removing most of the dissolved gas from pure water and ultrapure water as raw water, and a pressure reducing mechanism such as an appropriate vacuum pump is required. In addition, it is necessary to discharge a considerable amount of hydrogen as a dissolved gas, which has been a problem for ensuring safety.

  The present inventors can safely produce gas-dissolved cleaning water having a desired gas concentration without using a decompression mechanism such as a vacuum pump, and recycle the used gas-dissolved cleaning water and the specific gas. As an apparatus for producing gas-dissolved cleaning water that can be used suitably and can be used for cleaning of electronic parts that require high cleanliness, such as silicon wafers for semiconductors and glass substrates for flat panel displays , Gas dissolving device that dissolves specific gas in water under pressure exceeding atmospheric pressure, and gas dissolving water from gas dissolving device is reduced to a pressure lower than the pressure at the time of gas dissolution, and a part of dissolved gas is removed It has been found that an apparatus for producing gas-dissolved cleaning water having a gas partial removal device is useful. The usefulness of this gas-dissolved cleaning water production apparatus has been widely recognized, and it has been applied to a recovery and circulation system and has become popular as a new technology for wet cleaning.

With this gas-dissolved cleaning water manufacturing apparatus, it is possible to stably manufacture and reuse the gas-dissolved cleaning water having a high concentration of the specific gas and not being supersaturated. However, in this device, when the pressure of the supplied specific gas is low, etc., when trying to obtain a higher concentration of the specific gas dissolved water, a combination of the pressure gas dissolution and the supersaturation removal is combined. Need to be assembled in series in multiple stages, and there is a problem that the amount of supplied gas increases.
JP-A-11-77021

  The present invention uses gas-dissolved cleaning water obtained by dissolving a specific gas used for cleaning electronic parts that require high cleanliness, such as silicon wafers for semiconductors and glass substrates for flat panel displays, at a predetermined concentration. The object of the present invention is to provide an apparatus and a method for producing gas-dissolved cleaning water that can reduce the amount of gas and can supply gas efficiently and stably.

  As a result of intensive research to solve the above problems, the present inventors have arranged a gas permeable membrane module as a pre-dissolving part on the primary side of the apparatus that dissolves a specific gas under pressure and then removes the supersaturation. When the gas is passed through the gas phase chamber, specific gas-dissolved water with a high concentration can be obtained efficiently, and when a gas permeable membrane module is used for the supersaturated content removal section that removes the supersaturated content, By introducing exhaust gas containing a large amount of specific gas discharged from the phase chamber into the gas permeable membrane module of the pre-dissolution part, it is possible to further increase the concentration and save the amount of supply gas. Alternatively, by adjusting the gas pressure or the amount of gas supplied to the pressurized dissolution unit, the preliminary dissolution unit or the supersaturation removal unit according to the dissolved gas concentration on the primary side of the preliminary dissolution unit or the secondary side of the supersaturation removal unit , Predetermined concentration It found that it is possible to manufacture without waste of the supply gas specific gas dissolved water, and have completed the present invention based on this finding.

That is, the present invention
(1) In a gas-dissolved cleaning water manufacturing apparatus having a pressure-dissolving part that dissolves a specific gas in water in a supersaturated state under pressure under atmospheric pressure, and a supersaturated-content removing part that removes a supersaturated part of the specific gas. , Having a preliminary dissolution part equipped with a gas permeable membrane module on the primary side of the pressure dissolution part, supplying a specific gas to the gas phase chamber, and supplying the gas permeable membrane module of the preliminary dissolution part An apparatus for producing dissolved gas cleaning water, characterized in that the exhaust gas removed by the supersaturated content removal unit is used for part or all of the specific gas ,
( 2 ) Exhaust gas removed by the supersaturated content removing unit supplied a specific gas to the gas phase chamber of the gas permeable membrane module of the supersaturated content removing unit without exceeding the atmospheric pressure of the gas phase chamber. The apparatus for producing gas-dissolved cleaning water according to ( 1 ), which is exhaust gas that is later exhausted from the supersaturation removing unit,
( 3 ) A storage tank for storing wastewater after washing the object to be cleaned with a gas-dissolved cleaning water in which a specific gas is dissolved, a pump for pumping the water in the storage tank, and a cleaning effect in water. A purification apparatus for removing foreign substances to be applied, a pressure dissolving section for pressurizing and dissolving a specific gas, and an apparatus for producing gas-dissolved cleaning water having a cleaning water circulation mechanism having a supersaturated content removing section for removing a supersaturated content of a specific gas In the method for producing gas-dissolved cleaning water, the primary side of the pressure- dissolving unit has a pre-dissolution unit equipped with a gas permeable membrane module, and a specific gas is supplied to the gas-phase chamber, The dissolved gas concentration on the secondary side of the side or supersaturated content removal unit is measured, and according to the measured value, the flow rate or pressure of the specific gas supplied to the pressurized dissolution unit is adjusted, and the specific gas dissolved water with a predetermined concentration upon generating the gas permeation Makumo of predissolved portion Some or all of the specific gas for supply to Yuru, the method of manufacturing a gas dissolved cleaning water, which comprises using the exhaust gas are removed by supersaturated partial removal unit,
( 4 ) The exhaust gas removed by the supersaturated content removal unit supplied a specific gas to the gas phase chamber of the gas permeable membrane module of the supersaturated content removal unit without exceeding the atmospheric pressure of the gas phase chamber. ( 3 ) the method for producing gas-dissolved cleaning water, which is exhaust gas that is later exhausted from the supersaturated content removal section;
( 5 ) Measure the dissolved gas concentration on the primary side of the pre-dissolving part or the secondary side of the super-saturation removing part, and adjust the flow rate of the specific gas supplied to the pre-dissolving part or super-saturation removing part according to the measured value And ( 3 ) a method for producing gas-dissolved cleaning water, wherein specific gas-dissolved water having a predetermined concentration is generated.
Is to provide.

  By using the apparatus and method for producing gas-dissolved cleaning water of the present invention, it becomes possible to efficiently obtain high-concentration specific gas-dissolving cleaning water, and remove the primary side or supersaturated portion of the pressure-dissolving part or the pre-dissolving part. By adjusting the gas amount or the gas pressure of the specific gas supplied according to the dissolved gas concentration on the secondary side of the section, it becomes possible to produce the specific gas-dissolved cleaning water with a predetermined concentration without waste of the supply gas .

  The apparatus for producing gas-dissolved cleaning water according to the present invention includes a pressure-dissolving unit that dissolves a specific gas in water in a supersaturated state under a pressurized condition with respect to atmospheric pressure, and a supersaturated-content removing unit that removes a supersaturated component of the specific gas In the apparatus for producing gas-dissolved cleaning water, the apparatus has a preliminary dissolution part having a gas permeable membrane module on the primary side of the pressure-dissolution part, and supplies a specific gas to the gas phase chamber. In the apparatus of the present invention, it is preferable to use the exhaust gas removed by the supersaturation removing unit as a part or all of the specific gas supplied to the gas permeable membrane module in the preliminary dissolution unit.

  FIG. 1 is a process flow diagram of one embodiment of the apparatus for producing gas-dissolved cleaning water of the present invention. The waste water after washing the object to be washed in the washing treatment tank 3 and the gas-dissolved washing water that has not been used for washing are returned to the storage tank 1 via the washing waste water return pipe 2. The storage tank is supplied with makeup water from the makeup water pipe 4. The make-up water is preferably ultrapure water, but specific gas-dissolved water produced by a separate device can also be used. Nitrogen piping 5 is provided in the storage tank, and the specific gas in the space above the storage tank can be purged with nitrogen. When the specific gas is hydrogen or the like, the upper space of the storage tank is filled with high-concentration hydrogen, which is not preferable for safety management. Therefore, it is preferable to send nitrogen from a nitrogen pipe to lower the hydrogen concentration in the upper space to 4% by volume or less. The storage tank preferably has a pressure adjusting mechanism 6 and keeps the inside of the storage tank at a positive pressure. By providing a pressure adjusting mechanism that keeps the inside of the storage tank at a positive pressure, it is possible to prevent the inside of the storage tank from becoming negative pressure and being damaged due to a rapid drop in the water level in the storage tank. The storage tank 1 and the cleaning treatment tank 3 can also be used in the same tank. In this case, a makeup water pipe is connected to the storage tank / cleaning tank. Again, in order to make the hydrogen concentration in the upper space of the tank 4% by volume or less, it is preferable to purge with nitrogen or to exhaust sufficiently.

  Water is pumped out from the storage tank by the pressure pump 7 and the water temperature is adjusted by the heat exchanger 8 and then passed through the purification means 9 to remove foreign substances present in the water. Heat exchangers are mainly used to cool the temperature rise during circulation. However, it is possible to use water that has been warmed for cleaning without installing a heat exchanger for cooling. It can also be warmed. Although there is no restriction | limiting in particular in the installation position of a heat exchanger, It is preferable that it is the primary side of a purification means. Examples of the purification means used in the apparatus of the present invention include an ultrafiltration membrane (UF) apparatus. By passing the water through the purification means, foreign substances that substantially affect the cleaning present in the water can be removed together with a part of the water. The replenishment water replenishment position can be any position between the storage tank 1 and the secondary side of the purification means 9, but the secondary side of the purification means is preferable from the viewpoint of efficiently removing foreign substances. is there. However, since complicated control is involved in the operation of the apparatus, it is usually preferable to replenish a storage tank in which supply of makeup water is easily controlled. For example, by adjusting the amount of replenishment water so as to keep the water level in the storage tank constant, it can be balanced with the amount of water discharged substantially outside the system, and control is also facilitated.

  Foreign matter is removed by the purifying means, and the water flowing out from the purifying means is measured by the dissolved gas monitor 10 to measure the concentration of the specific gas, and the pre-dissolving portion 11 for dissolving the specific gas auxiliaryly before the pressure dissolution. The pressure dissolution unit 16 that dissolves the gas at a pressure higher than the atmospheric pressure and the supersaturated content removal unit 20 that removes the gas dissolved in supersaturation under a pressure not exceeding the atmospheric pressure including the specific gas are sent in this order. A specific gas is supplied to the gas phase chamber of the gas permeable membrane module of the pre-dissolving unit 11, and the specific gas is preliminarily dissolved before the pressure dissolution. The specific gas supplied here can be supplied independently from a specific gas supply source, or a part or all of the exhaust gas containing a large amount of the specific gas discharged from the supersaturated content removal unit can be used. it can. Moreover, even when supplying the exhaust gas from the supersaturated content removing section, it can be supplied from a specific gas supply source as necessary. The supply air flow rate to the preliminary melting part is controlled by the flow control valves 12 and 13 and is instructed by the flow meter 14. By controlling the flow rate control valve according to the measured value of the dissolved gas monitor 10 in the previous stage or the dissolved gas monitor 21 on the secondary side of the supersaturated content removal unit, the specific gas dissolved water having a predetermined concentration is supplied to the supply gas. It becomes possible to supply without waste. The exhaust gas discharged from the pre-dissolving section is rendered harmless through the gas combustion catalyst tower 15 and discharged out of the system.

  The water flowing out from the preliminary dissolution unit is supplied to the gas permeable membrane module of the pressure dissolution unit 16. The gas phase chamber of the gas permeable membrane module of the pressurized dissolution unit is maintained at a pressure higher than atmospheric pressure and lower than the water pressure of the place by the specific gas sent from the specific gas supply source 17. Dissolves above the saturation concentration at atmospheric pressure without foaming. The pressure in the gas phase chamber of the gas permeable membrane module of the pressure dissolution unit is controlled by the pressure regulating valve 18 and is indicated by the pressure gauge 19. By controlling the pressure regulating valve 18 according to the measured value of the dissolved gas monitor 10 or the dissolved gas monitor 21 in the previous stage, it is possible to supply the specific gas dissolved water having a predetermined concentration without waste of the supplied gas.

  The dissolved gas concentration of the cleaning wastewater returned to the storage tank varies depending on the cleaning conditions such as the ultrasonic irradiation time, the swinging behavior of the object to be cleaned and the jig holding it. For example, if it is returned in a high concentration, a specific gas-dissolved cleaning water with a predetermined concentration can be obtained even if the amount of supplied gas is small. Therefore, by measuring the concentration of the specific gas dissolved on the primary side that dissolves the specific gas, and increasing or decreasing the amount of the supplied gas according to the measured value, there is no waste of the supplied gas, and the specific gas dissolving cleaning with a predetermined concentration It becomes possible to supply water. In addition, since the dissolved gas concentration of the specific gas dissolved water supplied to the cleaning tank is the most important, measure the dissolved gas concentration after removing the supersaturated component, and depending on the measured value, Increasing or decreasing the amount of supplied gas is also effective.

  For the control of the amount of supplied gas, a method for controlling the flow rate of the supply gas to the preliminary dissolution unit or the supersaturated content removal unit, and the pressure of the supply gas to the pressurized dissolution unit or the flow rate of the supply gas are controlled. There is a way. When the control is performed by the preliminary dissolution part or the supersaturated content removal part, the control stability is good, and when the control is performed by the pressure dissolution part, the responsiveness is good. Control of the amount of supplied gas can be performed only in the pre-melting section, can be performed only in the pressure-melting section, or can be controlled in both the pre-melting section and the pressure-melting section. It can be appropriately selected depending on the case.

  The specific gas-dissolved water flowing out from the pressure dissolving unit is supplied to the gas permeable membrane module of the supersaturated component removing unit 20. By keeping the gas phase chamber of the gas permeable membrane module of the supersaturated content removal section at atmospheric pressure or slightly reduced pressure from atmospheric pressure, dissolved gas dissolved at the atmospheric pressure or higher than the saturation solubility into the gas phase chamber through the gas permeable membrane. Can move and be removed from the water. There is no particular limitation on the means for keeping the gas phase chamber at a slightly reduced pressure, but an airflow aspirator or the like can be easily applied and is preferable. The application position of the means for maintaining the slightly reduced pressure is suitable for the purpose immediately after the gas phase chamber outlet of the supersaturated content removal unit, but considering that the exhaust gas is reused, the primary side or the secondary side of the gas combustion catalyst tower 15 is Is preferred. The specific gas-dissolved cleaning water flowing out from the supersaturated content removal unit measures the specific gas concentration dissolved by the dissolved gas monitor 21, confirms that the desired dissolved gas concentration is obtained, and sends it to the cleaning treatment tank 3. Here, the dissolved gas monitor 10 at the front stage and the dissolved gas monitor 21 at the rear stage are configured such that, for example, the flow path is switched at regular intervals, and the water on the primary side of the preliminary dissolution unit 11 is obtained by one dissolved gas monitor. It can also be used so that the concentration of the specific gas in which both the water on the secondary side of the supersaturated content removal unit 20 is dissolved can be measured.

  The apparatus for producing the specific gas-dissolved cleaning water of the present invention includes a specific gas supply pipe for supplying the specific gas to the gas phase chamber without exceeding the atmospheric pressure, in which the supersaturation removing unit has a gas permeable membrane module. It is preferable to be connected. In the apparatus of the present invention, the exhaust gas removed by the supersaturated content removing unit supplies the specific gas to the gas phase chamber of the gas permeable membrane module of the supersaturated content removing unit without causing the pressure of the gas phase chamber to exceed atmospheric pressure. It is preferable that the exhaust gas is exhausted from the supersaturated content removal section after the air is supplied.

  FIG. 2 is a process flow diagram of another aspect of the apparatus for producing specific gas-dissolved cleaning water of the present invention. In the apparatus of this aspect, the flow control valve 22 and the flow meter 23 are installed in the supersaturated content removal unit of the apparatus shown in FIG. 1, and the atmospheric pressure from the specific gas supply source is exceeded in the gas phase chamber of the gas permeable membrane module. A specific gas is supplied at a pressure with no pressure. At this time, by controlling the supply gas flow rate according to the specific gas concentration of the specific gas dissolved water, it is possible to control the supply gas without waste.

  In the method for producing gas-dissolved cleaning water according to the present invention, a storage tank for storing waste water after cleaning an object to be cleaned with a gas-dissolved cleaning water in which a specific gas is dissolved, a pump for pumping water from the storage tank, A cleaning water circulation mechanism having a purifying means for removing foreign substances that substantially affect the cleaning present in the gas, a pressure dissolving section for pressurizing and dissolving the specific gas, and a supersaturated content removing section for removing the supersaturated content of the specific gas. In the specific gas-dissolved cleaning water manufacturing method using the specific gas-dissolved cleaning water manufacturing apparatus, the dissolved gas concentration on the primary side of the pressure-dissolving part or the secondary side of the supersaturated content removing part is measured, and according to the measured value Then, the flow rate or pressure of the specific gas supplied to the pressurized dissolution unit or the flow rate of the specific gas supplied to the supersaturated component removal unit is adjusted to generate specific gas dissolved water having a predetermined concentration. In the method of the present invention, the apparatus for producing gas-dissolved cleaning water of the present invention whose process system diagram is shown in FIG. 1 or 2 is used.

  In the method of the present invention, it is preferable to have a preliminary dissolution part equipped with a gas permeable membrane module on the primary side of the pressure dissolution part, and supply a specific gas to the gas phase chamber. Providing a pre-dissolving part on the primary side of the pressure-dissolving part, and preliminarily dissolving the specific gas before the pressure-dissolving, thereby efficiently producing gas-dissolved washing water in which a high-concentration specific gas is dissolved Can do.

  In the method of the present invention, the specific gas can be supplied to the gas phase chamber of the gas permeable membrane module of the supersaturated content removing section without exceeding the pressure of the gas phase chamber at atmospheric pressure. By controlling the flow rate of the specific gas supplied to the gas phase chamber in accordance with the concentration of the specific gas dissolved water flowing out from the supersaturated content removal unit, the flow rate of the specific gas supplied can be controlled without waste.

  In the method of the present invention, it is preferable to use the exhaust gas removed by the supersaturation removing unit as a part or all of the specific gas supplied to the gas permeable membrane module in the preliminary dissolution unit. Exhaust gas removed by the supersaturation removal unit is supplied to the gas phase chamber of the gas permeable membrane module of the supersaturation removal unit after supplying the specific gas without exceeding the atmospheric pressure of the gas phase chamber. The exhaust gas exhausted from the removal unit can be used. By supplying the exhaust gas containing the specific gas removed by the supersaturated content removal unit to the gas permeable membrane module of the preliminary dissolution unit, the specific gas can be efficiently used without being wasted.

  In the method of the present invention, the dissolved gas concentration on the primary side of the pre-dissolving part or the secondary side of the supersaturated part removing part is measured, and the specific gas supplied to the pre-dissolving part or supersaturated part removing part is measured according to the measured value. It is preferable to adjust the flow rate to generate specific gas-dissolved water having a predetermined concentration. By adjusting the flow rate of the specific gas supplied to the preliminary dissolution part or supersaturated content removal unit according to the measured value of the dissolved gas concentration on the primary side of the preliminary dissolution part or the secondary side of the supersaturated content removal part, the specific gas It can be used efficiently by avoiding unnecessary air supply.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1
Hydrogen-dissolved cleaning water was produced using an apparatus whose process is shown in FIG.
The storage tank 1 is returned with the hydrogen-dissolved cleaning water that has not been used for the drainage and cleaning after the object to be cleaned is cleaned in the cleaning processing tank 3 via the cleaning drainage return pipe 2. The storage tank is supplied with makeup water from the makeup water pipe 4. The storage tank is provided with a nitrogen pipe 5, and hydrogen in the space above the storage tank is purged with nitrogen. The storage tank has a pressure adjusting mechanism 6 and the inside of the storage tank is kept at a positive pressure.
Water was sent out from the storage tank by a pressure feed pump 7 at a water feed rate of 80 L / min and a water feed pressure of 0.2 MPa. After cooling with the heat exchanger 8 and adjusting the water temperature to 25 ° C., the filter was passed through a filter [Kurita Kogyo Co., Ltd., UF module, KU-1510HUT] 9 to remove foreign substances present in the water. The dissolved hydrogen concentration was measured by the dissolved hydrogen monitor 10, and water was passed through the pre-dissolution part 11 equipped with the gas permeable membrane module. The gas phase chamber of the gas permeable membrane module in the pre-dissolution part was supplied with exhaust gas containing hydrogen removed in the supersaturated content removal part 20. The flow rate of the exhaust gas containing hydrogen was controlled such that the flow control valve 12 was fully opened and 13 was fully closed, and the exhaust gas in the supersaturated content removal unit was supplied in its entirety. The exhaust gas discharged from the pre-dissolved part was rendered harmless through the hydrogen combustion catalyst tower 15 and discharged into the atmosphere.
The water flowing out from the preliminary dissolution unit was supplied to the gas permeable membrane module of the pressure dissolution unit 16. Hydrogen generated by the hydrogen generator 17 was supplied to the gas phase chamber of the gas permeable membrane module in the pressure dissolving section using a pressure regulating valve 18 and a pressure gauge 19 at a pressure of 0.1 MPa.
The hydrogen-dissolved water flowing out from the pressure dissolving part was supplied to the gas permeable membrane module of the supersaturated content removing part 20. In the gas-phase chamber of the gas permeable membrane module of the supersaturated component removal section, hydrogen generated by the hydrogen generator 17 is used by the flow control valve 22 and the flow meter 23, and 0.720 L (standard) during the operation of the cleaning treatment tank. State) / min (corresponding to 0.5 saturated hydrogen with respect to the water flow rate) and while the cleaning tank is stopped, the hydrogen supply is stopped (to 0 hydrogen with respect to the flow rate). Equivalent).
The hydrogen-dissolved cleaning water flowing out from the supersaturated content removal unit was measured for the dissolved hydrogen concentration by the dissolved hydrogen monitor 21 and sent to the cleaning treatment tank 3.
By the operation under the above conditions, the dissolved hydrogen concentration of the hydrogen-dissolved cleaning water supplied to the cleaning treatment tank was able to maintain the target 1.25 mg / L. The dissolved hydrogen concentration of the water on the primary side of the pre-dissolved part was 0.2 mg / L during the cleaning process, and 0.8 mg / L during the standby period when no cleaning was performed. This is because during cleaning, ultrasonic waves are applied to the cleaning water in the cleaning tank, or the object to be cleaned and the jig holding it are swung, so that dissolved hydrogen is removed from the cleaning tank. This is thought to be due to the fact that it moves to the phase and the dissolved concentration decreases. The amount of supplied hydrogen is summarized as follows: 1.5 saturation (2.15 L (standard state) / min) during the cleaning process, 1.0 saturation (1.43 L (standard state) / min) during standby, Hydrogen-dissolved washing water having a dissolved hydrogen concentration of 1.25 mg / L could be supplied.

Comparative Example 1
Hydrogen-dissolved cleaning water was manufactured using a hydrogen-dissolved cleaning water manufacturing apparatus having two combinations of the pressure-dissolving sections 24 and 26 and the supersaturated content removing sections 25 and 27 shown in FIG. Other devices are the same except that the pre-melting portion to the supersaturated content removing portion of the device shown in FIG. 2 are replaced with two combinations of the pressure dissolving portion and the supersaturated content removing portion shown in FIG.
Using an apparatus having a pressure dissolving part and a supersaturated content removing part shown in FIG. 3, it was decided to feed water at a dissolved hydrogen concentration of 1.25 mg / L or more. Since the hydrogen pressure was 0.1 MPa and the return concentration during the cleaning process had dropped to 0.2 mg / L, pressurization was necessary to obtain hydrogen-dissolved cleaning water having a dissolved hydrogen concentration of 1.25 mg / L. It was necessary to arrange the combination of the dissolving portion and the supersaturated portion removing portion in two stages in series. The amount of hydrogen to be supplied required 2.0 saturated portions in total because there were two pressure dissolution sections. The dissolved hydrogen concentration of the hydrogen-dissolved cleaning water sent at this time was 1.25 mg / L during the cleaning process, and 1.40 mg / L during the standby period when cleaning was not performed.
The results of Example 1 and Comparative Example 1 are shown in Table 1.

  As can be seen in Table 1, by using the gas-dissolved cleaning water manufacturing apparatus of the present invention, it is possible to reduce the hydrogen supply amount by 25% during the cleaning process and by 50% during the standby without cleaning. It turns out that it becomes.

  By using the apparatus and method for producing the specific gas-dissolved cleaning water of the present invention, the specific gas can be adjusted to a predetermined concentration, and the high-concentration specific gas-dissolved cleaning water can be supplied efficiently, stably and safely. . In particular, the apparatus and method of the present invention are suitable and highly practical when recycling a large flow of wash water.

It is a process flow diagram of one mode of a manufacturing device of gas dissolution washing water of the present invention. It is a process flow diagram of other modes of a manufacturing device of gas dissolution washing water of the present invention. It is a partial process systematic diagram of the apparatus used by the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Storage tank 2 Cleaning drainage return pipe 3 Cleaning process tank 4 Supplementary water piping 5 Nitrogen piping 6 Pressure adjustment mechanism 7 Pressure feed pump 8 Heat exchanger 9 Purifying means 10 Dissolved gas monitor 11 Preliminary dissolution part 12 Flow control valve 13 Flow control valve 14 Flow meter 15 Gas combustion catalyst tower 16 Pressurization dissolution part 17 Specified gas supply source 18 Pressure adjustment valve 19 Pressure gauge 20 Supersaturation removal part 21 Dissolved gas monitor 22 Flow control valve 23 Flowmeter 24 Pressure dissolution part 25 Supersaturation removal part 26 Pressure dissolution section 27 Supersaturated content removal section (Note that in the description of the examples, the specific gas or gas is read as hydrogen, and the purification means is read as a filter.)

Claims (5)

Pressurization in a gas-dissolved cleaning water manufacturing apparatus having a pressure-dissolving part that dissolves a specific gas in water under pressure under atmospheric pressure and a supersaturation removing part that removes a supersaturated part of the specific gas The primary part of the dissolution part has a preliminary dissolution part equipped with a gas permeable membrane module, supplies a specific gas to the gas phase chamber , and supplies a specific gas supplied to the gas permeable membrane module of the preliminary dissolution part An apparatus for producing gas-dissolved cleaning water, characterized in that the exhaust gas removed by the supersaturated content removal unit is used in part or in whole . After the exhaust gas removed by the supersaturated content removal section is supplied to the gas phase chamber of the gas permeable membrane module of the supersaturated content removal section without supplying the specific gas without exceeding the atmospheric pressure, the supersaturated content is removed. an exhaust gas discharged from the removal unit according to claim 1 gas dissolved cleaning water production apparatus according. A storage tank for storing waste water after cleaning the object to be cleaned with a gas-dissolved cleaning water in which a specific gas is dissolved, a pump for pumping the water in the storage tank, and a foreign substance that substantially affects the cleaning present in the water. Gas dissolving cleaning using a gas dissolving cleaning water production apparatus having a cleaning water circulation mechanism having a purifying means for removing, a pressure dissolving section for pressurizing and dissolving a specific gas, and a supersaturated content removing section for removing a supersaturated portion of the specific gas In the method for producing water, the primary side of the pressurized dissolution unit has a preliminary dissolution unit equipped with a gas permeable membrane module, and the gas phase chamber is supplied with a specific gas, and the primary side or supersaturation of the pressurized dissolution unit Measure the dissolved gas concentration on the secondary side of the minute removal unit, adjust the flow rate or pressure of the specific gas supplied to the pressurized dissolution unit according to the measured value, and generate the specific gas dissolved water with a predetermined concentration At the time, the gas permeable membrane module of the preliminary dissolution part Some or all of the specific gas to supply air, a manufacturing method of the gas dissolved cleaning water, which comprises using the exhaust gas are removed by supersaturated content removing unit. After the exhaust gas removed by the supersaturated content removal section is supplied to the gas phase chamber of the gas permeable membrane module of the supersaturated content removal section without supplying the specific gas without exceeding the atmospheric pressure, the supersaturated content is removed. The method for producing gas-dissolved cleaning water according to claim 3 , wherein the gas-dissolved cleaning water is exhaust gas exhausted from the removing section. Measure the dissolved gas concentration on the primary side of the pre-dissolution part or the secondary side of the supersaturation removal part, adjust the flow rate of the specific gas supplied to the preliminary dissolution part or supersaturation removal part according to the measured value, The method for producing gas-dissolved cleaning water according to claim 3 , wherein specific gas-dissolved water having a concentration is generated.

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