Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/20—Mixing gases with liquids
  • B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
  • B01F23/232—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using flow-mixing means for introducing the gases, e.g. baffles
  • B01F23/2326—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using flow-mixing means for introducing the gases, e.g. baffles adding the flowing main component by suction means, e.g. using an ejector
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/20—Mixing gases with liquids
  • B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
  • B01F23/232—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using flow-mixing means for introducing the gases, e.g. baffles
  • B01F23/2323—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using flow-mixing means for introducing the gases, e.g. baffles by circulating the flow in guiding constructions or conduits
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F21/00—Dissolving
  • B01F21/20—Dissolving using flow mixing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/20—Mixing gases with liquids
  • B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
  • B01F23/237—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media
  • B01F23/2373—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media for obtaining fine bubbles, i.e. bubbles with a size below 100 µm
  • B01F23/2375—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media for obtaining fine bubbles, i.e. bubbles with a size below 100 µm for obtaining bubbles with a size below 1 µm
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/20—Mixing gases with liquids
  • B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
  • B01F23/237—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media
  • B01F23/2376—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media characterised by the gas being introduced
  • B01F23/23761—Aerating, i.e. introducing oxygen containing gas in liquids
  • B01F23/237612—Oxygen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
  • B01F25/30—Injector mixers
  • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
  • B01F25/312—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof
  • B01F25/3124—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof characterised by the place of introduction of the main flow
  • B01F25/31242—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof characterised by the place of introduction of the main flow the main flow being injected in the central area of the venturi, creating an aspiration in the circumferential part of the conduit
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
  • B01F25/30—Injector mixers
  • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
  • B01F25/314—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced at the circumference of the conduit
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
  • B01F25/50—Circulation mixers, e.g. wherein at least part of the mixture is discharged from and reintroduced into a receptacle
  • B01F25/51—Circulation mixers, e.g. wherein at least part of the mixture is discharged from and reintroduced into a receptacle in which the mixture is circulated through a set of tubes, e.g. with gradual introduction of a component into the circulating flow
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/71—Feed mechanisms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F2101/00—Mixing characterised by the nature of the mixed materials or by the application field
  • B01F2101/48—Mixing water in water-taps with other ingredients, e.g. air, detergents or disinfectants

Definitions

• the present invention relates to a method of dissolving a gas in a water stream.
• a useful gas such as carbon dioxide gas is dissolved into a water stream, thereby increasing its concentration.
• Patent Literature 1 As for a gas dissolving apparatus described in Patent Literature 1, it is disclosed that carbon dioxide gas stored in a gas cylinder is supplied to a collision portion where fine bubbles are generated.
• Patent Literature 2 discloses a method of pressurizing a gas and dissolving the gas into water.
• Patent Literature 1 As for the gas dissolving apparatus described in Patent Literature 1, the mixing of the gas with water progresses remarkably in a strong stirring region downstream of the collision portion, and the dissolution of the gas is efficiently carried out (see Patent Literature 1, page 21, paragraphs 2 and 3).
• Patent Literature 3 In addition, please refer to Patent Literature 3 and Patent Literature 4.
• gas such as oxygen has been needed to be pressurized to be forcibly dissolved into water, and for example, an oxygen cylinder or the like has been needed to be prepared. For this reason, its apparatus has become complicated, and not only its cost has increased, but also its maintenance has taken time and effort.
• the present invention has been made to solve the above-mentioned problems, and a first aspect thereof is defined as follows. That is,
• a gas from a gas supply source is sucked due to negative pressure in the negative pressure region, and this gas is entrained in the water stream.
• this gas is entrained in the water stream.
• a part of the water is gasified (vaporized) in the negative pressure region of the water stream.
• the gas is introduced into the negative pressure region, the gas and water vapor in the negative pressure region are mixed. Then, with an increase of the pressure of a part of the water stream that has flown out from the negative pressure region, the water vapor condenses and turns back to water. At this time, the gas is drawn into water and becomes in a state of being dissolved in water.
• the gas is also present in the fine bubbles, which prevents a decrease in the concentration of the gas dissolved in water.
• gas suction is caused by negative pressure in the negative pressure region. Therefore, there is no need for an external pressure device for feeding gas.
• a second aspect of the present invention is defined as follows. That is, in the method of the first aspect, the gas in a state at atmospheric pressure is sucked into the negative pressure region.
• an adsorption separation method is generally employed, and oxygen produced by such a production method is not in a pressurized state.
• unpressurized oxygen which is taken out from an adsorption separation device as an oxygen supply source, can be directly dissolved in water, that is, oxygen in a state at atmospheric pressure can be dissolved in water.
• a third aspect of the present invention is defined as follows. That is, in the gas dissolving method of the first aspect, the water stream flows through a tube, a vertical downstream wall facing downstream of the water stream is provided in the tube, and the water stream flows along the downstream wall to create the negative pressure region.
• the water stream flowing around along the downstream wall moves away from the center of the tube, and creates the negative pressure region on the outer peripheral side of the tube. It becomes easier to supply the gas into such a negative pressure region from outside the tube.
• Patent Literature 4 states that water is caused to pass through a tube having a vertical downstream wall and thereby fine bubbles including nano-order ultrafine bubbles are created in water (see Figs. 4 and 5 ).
• a small-diameter portion (an orifice) is preferably provided in the tube, and a vertical downstream wall is preferably formed at an outlet of the small-diameter portion.
• a fourth aspect of the present invention is defined as follows. That is, in the gas dissolving method of the third aspect, a recess is formed in the downstream wall, and a part of the water stream that has flown into the recess is vaporized due to negative pressure in the recess.
• the negative pressure is extremely great in the recess formed in the downstream wall. According to the study of the present inventors, in this recess, the pressure varies (oscillates), and the water is almost completely vaporized in the state at the maximum negative pressure.
• the gas supplied to the negative pressure region is introduced into the water stream and reaches the recess, the gas is drawn into the recess by the great negative pressure in the recess and is mixed with water vapor in the recess.
• the gas can be supplied directly to the recess.
• a fifth aspect of the present invention is defined as follows. That is,
• the recess penetrates into the peripheral wall of the tube, so that a part of the recess is in a state of being covered with a lid from the wall. According to the study of the present inventors, vaporization of water is promoted in the recess of the portion covered with the lid.
• a seventh aspect of the present invention is defined as follows. That is, an apparatus through which a gas is dissolved into a water stream from a water stream source, the apparatus comprising: a supply source of the gas; and a dissolving section, the dissolving section comprising:
• the gas of the supply source of the gas is supplied to the negative pressure region through the gas supply passage due to negative pressure in the negative pressure region, and thus no gas pressurizing device (including a pump) is required. Therefore, the number of components in the entirety of the apparatus is reduced, and an inexpensive apparatus becomes available. Moreover, according to the gas dissolving apparatus including the dissolving section, fine bubbles are also generated in the dissolving section.
• the target gas is the atmospheric air
• the atmosphere itself is the gas supply source. Therefore, the end portion of the gas supply passage on the side of the gas supply source is in a state of being open to the atmosphere.
• the water stream having passed through the gas dissolving apparatus can be fed back to the water stream source. That is, water in a tank is circulated, and the circulating water stream is allowed to pass through the dissolving section. It has been found that the temperature of the circulating water is not increased at all when this gas dissolving apparatus is applied to such a circulation system. This is thought to be because no mechanical external force such as agitation is applied to the water stream, in addition to that the gas does not need to be pressurized at all as dissolving the gas.
• a recess can be formed in the downstream wall. A part of the water stream flowing into the recess is vaporized due to negative pressure in the recess (an eighth aspect).
• a gas supply passage has an opening in the recess. Since enhanced negative pressure is generated in the recess, the gas can be efficiently sucked from the outside. In addition, since water vaporization is promoted due to the enhanced negative pressure, the gas is entrained in water when the water vapor turns back to water, so that the gas is dissolved at a high concentration.
• the gas supply passage preferably has an opening at a position opposing this recess (an eleventh aspect).
• the recess can be penetrated into the peripheral wall of the tube (a tenth aspect).
• a part of the recess is in a state of being covered with a lid. According to the study of the present inventors, water vaporization is promoted in the recess of the portion covered with the lid.
• fine bubbles are efficiently generated in the water stream when such a recess is provided as stated in Patent Literature 4.
• fine bubbles include nano-order ultrafine bubbles.
• the gas that can be selected is one type or two or more types selected from an inorganic gas such as atmospheric air, oxygen, ozone, ammonia, or nitrogen, or an organic gas such as carbon dioxide or ethane.
• an inorganic gas such as atmospheric air, oxygen, ozone, ammonia, or nitrogen
• an organic gas such as carbon dioxide or ethane.
• a gas dissolving apparatus 1 according to a first embodiment of the present invention is described bellow.
• the gas dissolving apparatus 1 comprises a gas supply source 10, a water stream source 100, and a dissolving section 500.
• an adsorption separation type oxygen generator was employed as the gas supply source 10.
• the oxygen output from this oxygen generator is in a state at atmospheric pressure.
• any gas to be dissolved in the water stream can be selected.
• a tank or cylinder of such a gas can be used as the gas supply source 10.
• the atmosphere can also be used as the gas supply source.
• a general-purpose pump can be used as the water stream source 100.
• the pressure of the water stream and the amount of water delivered by the pump can be set freely.
• a tap can be directly used as the water stream source.
• the dissolving section 500 comprises a tubular portion 600 and a bubble generator 1000.
• this bubble generator 1000 is described in Patent Literature 3 ( JP 6279179 B2 ), and the description thereof is incorporated herein by reference.
• the tubular portion 600 is divided into parts in axial direction (water stream direction).
• An upstream part 610 thereof is connected to the water stream source 100 through a conduit 200.
• An inlet of the water stream comprises: a funnel-shaped part 611 whose diameter decreases in the water stream direction; and an inlet-side orifice 612.
• An outlet-side orifice 632 is formed in a downstream part 630.
• the two orifices 612 and 632 have the same diameter.
• Fig. 1 is a cross section taken along line A-A in Fig. 2 .
• This bubble generator 1000 comprises a main body 1100 and a bubble generating part 1200.
• the main body 1100 is formed into a tubular shape. A part of the outer peripheral surface of this main body 1100 is cut out to form a flat portion 1110. This flat portion prevents unnecessary rotation and is used for positioning.
• the main body 1100 does not need to have a cylindrical shape, and can have any shape. For example, it may have a rectangular tubular shape. It may also be radically divided into parts. It may also have a tapered shape whose diameter becomes smaller toward the downstream in the water stream direction.
• the bubble generating part 1200 has a columnar portion 1210, which protrudes from an inner peripheral surface of the main body 1100 and is formed integrally with the main body 1100.
• a columnar portion 1210 which protrudes from an inner peripheral surface of the main body 1100 and is formed integrally with the main body 1100.
• six columnar portions 1210 are included.
• Each of slits 1300 is formed between the columnar portions 1210.
• the slits 1300 are formed radially in a plan view.
• the center of radiation coincides with the central axis of the main body 1100.
• the center of radiation does not need to coincide with the central axis of the main body 1100.
• the slits 1300 are formed on one virtual transverse plane in the main body 1100.
• a part most protruding from the inner peripheral surface of the main body 1100 is formed on the virtual transverse plane. This most protruding part preferably coincides with the peripheral edge of a bottom surface 1211 of the columnar portion 1210.
• This bottom surface 1211 is, in its most protruding part, preferably formed perpendicularly or at an acute angle with respect to the water stream direction. This is because a greater change in flow velocity can be produced to generate negative pressure there.
• Recesses 1220 are formed in the bottom surface 1211. The water stream passed through the slits 1300 and flown over the bottom surface side is affected sucking by the recesses 1220 so that the negative pressure generation on the bottom surface 1211 is promoted.
• the recesses 1220 are preferably arranged evenly and radially from the center of the slits 1300, that is, from the central axis of the main body 1100.
• Each of the recesses 1220 is extended to the main body 1100.
• the portion of the recess 1220 existing in the main body 1100 serves as a cavity during use. Water about to flow into the recess 1220 interferes with water already existing in the recess 1220, but the interference is buffered by this cavity. Therefore, the negative pressure creating effect is enhanced.
• each of the slits 1300 is formed to have the same width, but a change in width can be allowed.
• the change in width mentioned here means that the widths of the slits are different from each other, and means that a change in width is allowed in one slit.
• the cross-sectional area of the columnar portion 1210 becomes gradually smaller from the bottom surface 1211 toward the upstream side. Then, the cross-sectional area becomes zero on its upstream side surface. As a result, the resistance of the columnar portion to the water stream can be reduced. In addition, by adopting such a structure, pulling out of a mold can be performed without any resistance during mold forming.
• the columnar portion 1210 in this example has a pyramid shape whose bottom surface 1211 is a surface defined by each of edges 1310 of the slit 1300.
• the ridgeline of the columnar portion 1210 is defined as follows. That is, one terminal point of the ridgeline is defined at cross point of the adjacent edges 1310 and 1310. The other terminal point of the ridgeline is defined at the point where the most upstream point of the inner peripheral surface of the main body 1100 crossing the virtual bisecting surface of the edges 1310 and 1310.
• a gas supply passage 700 is disposed between the gas supply source 10 and the orifice 632.
• This gas supply passage 700 is formed of a pipe, one end of which is connected to the gas supply source 10, and the other end of which is open to the orifice 632.
• the other end of the gas supply passage 700 can be open to and face the recess 1220. This makes it possible to efficiently supply the gas to the water stream that flows into the recess 1220.
• the other end of the gas supply passage 700 can be open in the recess 1220 (a gas dissolving apparatus 2).
• the water stream supplied from the water stream source 100 through the conduit 200 to the dissolving section 500 is compressed at the funnel-shaped part 611 and the water stream is enhanced. This water stream is further compressed at the columnar portion 1210 of the bubble generating part 1200. After having passed through the slit 1300, such a water stream creates a negative pressure region in the orifice 632 on the downstream side and creates small bubbles. As a result, fine bubbles are generally formed in the negative pressure region (a cavitation effect).
• a negative pressure region is also created in a region close to the bottom surface 1211 in an outer region (a region close to the peripheral wall of the tubular portion) of the orifice 632 on the downstream side.
• Fig. 4 illustrates a gas dissolving apparatus 3 according to another embodiment. Note that the same elements as those in Fig. 1 are denoted by the same reference numerals, and the description thereof will be omitted.
• a dissolving section 2100 of this gas dissolving apparatus 3 includes an introduction part 2210, an orifice 2220, and an enlarged diameter part 2230, which are sequentially formed in a tubular main body 2200, from the upstream thereof. Note that the dissolving section 2100 is described in JP 6978793 B2 (Patent Literature 4), and therefore the description thereof is incorporated herein by reference.
• the orifice 2220 refers to a reduced diameter portion of the same diameter in the tubular main body.
• the diameter can be changed and/or a groove can be formed on the peripheral wall of the orifice to the extent that no disturbance occurs in the water stream.
• the configuration of the dissolving section 2100 generates fine bubbles as disclosed in JP 2021-20153 A by the present applicant. That is, a negative pressure region is created in the enlarged diameter part 2230 and in the recess 2250.
• the other end of the gas supply passage 700 is open to the enlarged diameter part 2230.
• the gas supply passage 700 may have an opening in the recess 2250 (a gas dissolving apparatus 4).
• An oxygen gas dissolution test was performed by using the gas dissolving apparatus 1 illustrated in Fig. 1 .
• Tap water (at water temperature of 20.0°C) in an opened tank was introduced at an amount of water (8 L/min) and a water pressure of 0.3 MPa into the gas dissolving apparatus 1.
• An adsorption separation type oxygen generator (Orginator 601 manufactured by Kinkisanso Co., Ltd.) was used as the oxygen gas supply source 10, and oxygen gas not pressurized at all in a state at atmospheric pressure was enabled to be supplied to the gas supply passage 700.
• Fig. 6 shows the relationship between the oxygen gas supply flow rate and the dissolved oxygen concentration when the supply flow rate of the oxygen gas was changed under the aforementioned conditions.
• the supply flow rate of the oxygen gas is preferably from 1 L/min to 2 L/min under the aforementioned conditions.
• Fig. 7 shows the changes in the dissolved oxygen concentration over time in the water with dissolved oxygen obtained in this way.
• Tap water in a 500-L tank was used as a target to be treated, while the tap water in the tank was circulated at a water amount (8 L/min) and a water pressure of 0.3 MPa with a circulation device equipped with a pump, a pipe, and a valve, the circulating water stream was caused to pass through the gas dissolving apparatus 1.
• the dissolved oxygen concentration in the tap water in the tank before circulation was 10.8 mg/L.
• the dissolved oxygen concentration in the tap water in the tank after circulation for 60 minutes (480 L circulation) was 28.8 mg/L, and the dissolved oxygen concentration in the tap water in the tank after circulation for 120 minutes (960 L circulation) was 37.9 mg/L. It can be seen from this that the dissolved oxygen concentration in the tap water increased by approximately four times higher than that before circulation.
• the dissolved oxygen concentration was measured with Model No.: HI98198 manufactured by Hanna Instruments.
• Fig. 8 shows the relationship between water pressure and the dissolved oxygen concentration when the oxygen supply device 10 was removed, the gas supply passage 700 was open to the atmosphere, and the water pressure was varied in the apparatus of Fig. 1 . It should be noted that fine bubbles were generated at each water pressure.

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• 2024
  • 2024-07-24 JP JP2024569716A patent/JP7725118B2/ja active Active
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