This invention relates to generating nano-bubbles in a liquid carrier.
Nano-bubbles are stable in liquid carriers for extended periods of time, allowing them to be transported without coalescing in the liquid carrier. These properties make nano-bubbles useful in a variety of fields, including water treatment, plant growth, aquaculture, and sterilization.
In a first aspect, an apparatus for generating a composition that includes nano-bubbles in a liquid carrier is described. The apparatus includes: (a) an elongate housing that includes a first end and a second end, and defines a liquid inlet, a liquid outlet, and an interior cavity adapted for receiving the liquid carrier from a liquid source; (b) a gas-permeable member at least partially disposed within the interior cavity of the housing that includes a first end adapted for receiving a pressurized gas from a gas source, a second end, and a porous sidewall extending between the first and second ends, the gas-permeable member defining an inner surface, an outer surface, and a lumen; and (c) at least one electrical conductor adapted to generate a magnetic flux parallel to the outer surface of the gas-permeable member as the liquid carrier flows from the liquid inlet to the liquid outlet. The housing and gas-permeable member are configured such that the flow rate of the liquid carrier from the liquid source as it flows parallel to the outer surface of the gas-permeable member from the liquid inlet to the liquid outlet is greater than the turbulent threshold of the liquid to create turbulent flow conditions, thereby allowing the liquid to shear gas from the outer surface of the gas-permeable member and form nano-bubbles in the liquid carrier.
In some embodiments, the gas-permeable member is electrically conductive. The electrical conductor may be an electromagnetic coil (e.g., a stator) or a wire. In some cases, the apparatus includes a pair of electrical conductors, one of which is the gas-permeable member and the other of which is, e.g., an electromagnetic coil or a wire.
In some embodiments, the apparatus includes a helicoidal member adapted to cause the liquid carrier to rotate as it flows from the liquid inlet to the liquid outlet. The helicoidal member may be in the form of a pattern integral to the gas-permeable member, the housing, or both. In other embodiments, the helicoidal member includes an electromagnetic coil adapted to generate a magnetic flux parallel to the outer surface of the gas-permeable member as the liquid carrier flows from the liquid inlet to the liquid outlet. In the latter case, the helicoidal member also performs the role of the electrically conductive member.
The electrical conductor may be located on the exterior of the housing, in the interior cavity of the housing, or on the outer surface of the gas-permeable member. The electrical conductor may also be located downstream or upstream of the gas-permeable member.
The apparatus may further include a hydrofoil located in the interior cavity of the housing. The hydrofoil may be located upstream or downstream of the gas-permeable member. In some embodiments, the hydrofoil is physically attached to the gas-permeable member. The hydrofoil causes the liquid carrier to rotate as it flows past the hydrofoil.
In a second aspect, a second apparatus for producing a composition that includes nano-bubbles dispersed in a liquid carrier is described. The apparatus includes: (a) an elongate housing that includes a first end and a second end, and defines a liquid inlet, a liquid outlet, and an interior cavity adapted for receiving the liquid carrier from a liquid source; (b) a gas-permeable member at least partially disposed within the interior cavity of the housing, the gas-permeable member including a first end adapted for receiving a pressurized gas from a gas source, a second end, and a porous sidewall extending between the first and second ends, the gas-permeable member defining an inner surface, an outer surface, and a lumen; (c) one or more electrodes, one of which is an electromagnetic coil adapted to generate a magnetic flux parallel to the outer surface of the gas-permeable member as the liquid carrier flows from the liquid inlet to the liquid outlet, (d) a helicoidal member adapted to cause the liquid carrier to rotate as it flows from the liquid inlet to the liquid outlet, and (e) a hydrofoil located in the interior cavity of the housing. The housing and gas-permeable member are configured such that the flow rate of the liquid carrier from the liquid source as it flows parallel to the outer surface of the gas-permeable member from the liquid inlet to the liquid outlet is greater than the turbulent threshold of the liquid to create turbulent flow conditions, thereby allowing the liquid to shear gas from the outer surface of the gas-permeable member and form nano-bubbles in the liquid carrier.
In some embodiments, the helicoidal member includes the electromagnetic coil.
In a third aspect, a method for producing a composition including nano-bubbles dispersed in a liquid carrier using the apparatus described in the first and second aspects of the invention is described. The method includes: (a) introducing a liquid carrier from a liquid source into the interior cavity of the housing through the liquid inlet of the housing at a flow rate that creates turbulent flow above the turbulent threshold at the outer surface of the gas-permeable member; (b) applying a magnetic flux parallel to the outer surface of the gas-permeable member as the liquid carrier flows from the liquid inlet to the liquid outlet; and (c) introducing a pressurized gas from a gas source into the lumen of the gas-permeable member at a gas pressure selected such that the pressure within the lumen is greater than the pressure in the interior cavity of the housing, thereby forcing gas through the porous sidewall and forming nano-bubbles on the outer surface of the gas-permeable member. The liquid carrier flowing parallel to the outer surface of the gas-permeable member from the liquid inlet to the liquid outlet removes nano-bubbles from the outer surface of the gas-permeable member to form a composition comprising the liquid carrier and the nano-bubbles dispersed therein.
In some embodiments, the flow rate is at least 2 m/s. The method may include applying an oscillating magnetic flux, e.g., a high frequency oscillating magnetic flux.
In a fourth aspect, a third apparatus for producing a composition including nano-bubbles dispersed in a liquid carrier is described. The apparatus includes: (a) an elongate housing including a first end and a second end, the housing further including an interior cavity and a gas inlet adapted for introducing pressurized gas from a gas source into the interior cavity; (b) a gas-permeable member at least partially disposed within the interior cavity of the housing, the gas-permeable member including a liquid inlet adapted for receiving a liquid from a liquid source, a liquid outlet, and a porous sidewall extending between the liquid inlet and liquid outlet, and defining an inner surface, an outer surface, and a lumen through which liquid flows; and (c) at least one electrical conductor adapted to generate a magnetic flux parallel to the inner surface of the gas-permeable member as the liquid carrier flows from the liquid inlet to the liquid outlet. The housing and gas-permeable member are configured such that the flow rate of the liquid carrier from the liquid source as it flows parallel to the inner surface of the gas-permeable member from the liquid inlet to the liquid outlet is greater than the turbulent threshold of the liquid to create turbulent flow conditions, thereby allowing the liquid to shear gas from the inner surface of the gas-permeable member and form nano-bubbles in the liquid carrier.
In a fifth aspect, a method for producing a composition including nano-bubbles dispersed in a liquid carrier using the apparatus described in the fourth aspect of the invention is described. The method includes: (a) introducing a liquid carrier from a liquid source into the interior cavity of the gas-permeable member through the liquid inlet of the housing at a flow rate that creates turbulent flow above the turbulent threshold at the outer surface of the gas-permeable member; (b) applying a magnetic flux parallel to the inner surface of the gas-permeable member as the liquid carrier flows from the liquid inlet to the liquid outlet; and (c) introducing a pressurized gas from a gas source into the interior cavity of the housing at a gas pressure selected such that the pressure within the interior cavity of the housing is greater than the pressure in the interior of the gas-permeable member, thereby forcing gas through the porous sidewall and forming nano-bubbles on the inner surface of the gas-permeable member. The liquid carrier flowing parallel to the inner surface of the gas-permeable member from the liquid inlet to the liquid outlet removes nano-bubbles from the inner surface of the gas-permeable member to form a composition comprising the liquid carrier and the nano-bubbles dispersed therein.
In some embodiments, the flow rate is at least 2 m/s. The method may include applying an oscillating magnetic flux, e.g., a high frequency oscillating magnetic flux.
In each of the above-described apparatuses and methods, configuring the apparatus such that the flow rate of the liquid carrier from the liquid source as it flows parallel to the inner or outer surface of the gas-permeable member from the liquid inlet to the liquid outlet is greater than the turbulent threshold of the liquid to create turbulent flow conditions minimizes nano-bubble coalescence. Including at least one electrical conductor to generate a magnetic flux (e.g., a high frequency oscillating magnetic flux) parallel to the inner or outer surface of the gas-permeable member as the liquid carrier flows from the liquid inlet to the liquid outlet increases both nano-bubble production and nano-bubble production rate. Measuring the change in resistance of the electrical conductor can be used to detect the presence of nanobubbles in the fluid.
The helicoidal member further increases nano-bubble production and nano-bubble production rate by imparting angular velocity to the liquid carrier to cause swirling, thereby enhancing the efficiency of capturing nano-bubbles at the interface between gas-permeable member and liquid stream. The hydrofoil further increases nano-bubble production and nano-bubble production rate by creating high turbulence regions in the fluid flowing through the apparatus based on the surface of the hydrofoil and the turbulent trailing edge downstream of the hydrofoil.
The apparatuses and methods described above can be used in a variety of applications. Examples include water treatment, e.g., wastewater treatment to oxygenate and/or remove contaminant in a body of water. Other examples include aquaculture and plant growth, where the composition can be used to deliver oxygen or other nutrients. Yet another example is cleaning and sterilization, e.g., in hot tubs or spas to minimize or eliminate the use of chemicals such as chlorine.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
Like reference symbols in the various drawings indicate like elements.
This disclosure describes an apparatus for producing nano-bubbles in a liquid carrier. The nano-bubbles have diameters less than one micrometer (μm). In some embodiments, the nano-bubbles have diameters less than or equal to 500 nanometers (nm). In some embodiments, the nano-bubbles have diameters less than or equal to 200 nanometers (nm).
The apparatuses and methods described herein selectively apply a combination of super-cavitation, vorticity, and/or a magnetic field (preferably a high frequency oscillating magnetic field) in addition to shear to form nano-bubbles in a liquid carrier.
The apparatus 100 includes the gas-permeable member 103 at least partially disposed within the interior cavity of the housing 101. The permeable member 103 defines an inner surface, an outer surface, and a lumen. The permeable member 103 can include a first end 103a adapted for receiving a pressurized gas from a gas source, a second end 103b, and a porous sidewall 103c extending between the first and second ends 103a, 103b. The first end 103a of the permeable member 103 can be an open end and the second end 103b of the permeable member 103 can be a closed end.
The housing 101 and permeable member 103 can be arranged such that the flow rate of the liquid carrier from the liquid source, as it flows parallel to the outer surface of the permeable member 103 from the liquid inlet to the liquid outlet, is greater than the turbulent threshold of the liquid to create turbulent flow conditions, thereby allowing the liquid to shear gas from the outer surface of the gas-permeable member and form nano-bubbles in the liquid carrier.
As shown in
The electrical conductor 105 can be located on the outer surface of the permeable member 103. The electrical conductor 105 can surround at least a portion of the permeable member 103. The electrical conductor 105 can also be implemented in other forms. For example, in some embodiments, the electrical conductor 105 includes a wire. In some embodiments, the electrical conductor 105 includes one or more electrodes. In some embodiments, the electrical conductor 105 is in the form of an electromagnetic coil (e.g., a stator). In some embodiments, the permeable member 103 can serve as the electrical conductor 105.
In some embodiments, the apparatus 100 is connected to a source of liquid that provides the liquid carrier (for example, water). In some embodiments, the source of liquid is a vessel or body of water connected to a pump via a suction line. In some embodiments, the pump is a variable speed pump. In some embodiments, the pump is connected to the apparatus 100 via a discharge line with a control valve. In some embodiments, the discharge line is in fluid communication with the housing 101. For example, the liquid carrier flows from the pump, through the control valve, through the discharge line, and to the first end 101a. The percent opening of the control valve can be adjusted to control the pressure and flow rate of the liquid carrier to the apparatus 100.
The apparatus 100 can optionally include a hydrofoil 150 shaped to induce rotation in the liquid carrier flowing through the apparatus 100. In some embodiments, the hydrofoil 150 is shaped (e.g., with tapered and/or curved surfaces) to induce super-cavitation in the liquid carrier flowing through the apparatus 100. For example, the hydrofoil 150 can be shaped to create high turbulence regions in the fluid flowing through the apparatus 100 based on the surface of the hydrofoil 150 and the turbulent trailing edge downstream of the hydrofoil 150. In this disclosure, the terms “downstream” and “upstream” are in relation to the overall flow direction of the liquid carrier, for example, through the apparatus 100. For example, in
As shown in
In some embodiments, the apparatus 100 optionally includes a mount 151. The mount can serve to couple two or more components together in the apparatus. As shown in
The apparatus 100 is connected to a source of gas. As discussed above, the source of gas can be connected to the port 151a (defined by the mount 151), which is in fluid communication with the first end 103a of the permeable member 103. The gas can flow to the first end 103a and into the lumen of the permeable member 103. As the gas flows from the lumen and through the pores of the permeable member 103, nano-bubbles can be formed and sheared from the outer surface of the permeable member 103 by the liquid carrier flowing across the outer surface of the permeable member 103 at a flow rate above the turbulent threshold of the liquid.
In some embodiments, the liquid carrier containing the nano-bubbles formed by the apparatus 100 flows out of the apparatus 100 (for example, out of the second end 101b) to a discharge line. In some embodiments, the liquid carrier containing the nano-bubbles formed by the apparatus 100 flows out of the apparatus 100 to multiple selectable discharge lines (for example, in a vessel or body of water).
The apparatus 200 of
In some embodiments, the helicoidal member 207 can be an integral feature of the permeable member 103, the housing 201, or both, that causes the liquid carrier to rotate. For example, the helicoidal member 207 can include one or more surface features on a wall of the permeable member 103, the housing 201, or both, that causes the liquid carrier flowing adjacent to the surface to rotate. The surface features may include cavities and/or protrusions on a wall. For example, the helicoidal member 207 can include a helical-shaped surface formed along an inner wall of the housing in some embodiments.
The apparatuses provided herein can include various electrical conductor configurations. In some embodiments, one or more electrical conductors (e.g., electrical conductor 205 or helicoidal member 207) are separate components within the apparatus 200. For example, the electrical conductor 205 and the helicoidal member 207 can be separate components coupled directly to the housing 201 (as shown in
Gas can be flowed into the permeable member 103 such that as liquid flows around the outer surface of the permeable member 103, the gas flows from the lumen of the permeable member 103 through the pores to generate nano-bubbles along the surfaces of the permeable member 103. The liquid flowing around the permeable member 103 shears the nano-bubbles from the permeable member to yield a nano-bubble enriched liquid.
The housing 1201 of apparatus 1200 includes a first end 1201a and a second end 1201b that are closed ends. A gas flows from a source through a port 1201c defined by the housing 1201 into an interior cavity of the housing 1201. Although shown in
The permeable member 1203 has a first end 1203a that can serve as a liquid inlet adapted for receiving a liquid carrier. The permeable member 1203 includes pores that allow a gas to pass through its walls. The permeable member 1203 is enclosed within the interior cavity of the housing 1201 such that the gas within the housing flows across the walls of the permeable member 1203. Pressure is applied to flow gas through the pores of the permeable member 1203 and into the lumen of the permeable member 1203. As the gas flows through the pores of the permeable member 1203, nano-bubbles are formed. The liquid carrier flowing through the lumen of the permeable member 1203 shears the nano-bubbles from an inner surface of the permeable member 1203 as they form. The second end 1203b of the permeable member 1203 can be an open end or an outlet for discharging the liquid carrier carrying formed nano-bubbles.
The apparatus 1200 of
Apparatus 1200 can optionally include a component (e.g., helicoidal member and/or a hydrofoil) to induce rotation in the liquid flowing through the permeable member 1203, as described previously herein. The optional component can be located in the interior cavity of the housing 1201. For example, the optional component can be coupled to the permeable member 1203. In some embodiments, the optional component is integral to the permeable member 1203. For example, the optional component can be a helicoidal member that includes a helical baffle or coil disposed about an inner surface of the permeable member 1203. In some embodiments, at least a portion of the optional component is located upstream or downstream of the permeable member 1203. In some embodiments, apparatus 1200 includes the hydrofoil, the helicoidal member, and/or the electrical conductor 1205, which can cooperatively induce rotation in the fluid flowing through the apparatus 1200.
Any of the apparatuses and methods described herein include producing nano-bubbles having a mean diameter less than 1 μm in a liquid volume. In some embodiments, the nano-bubbles have a mean diameter ranging from about 10 nm to about 500 nm, about 75 nm to about 200 nm, or about 50 nm to about 150 nm. The nano-bubbles in the composition may have a unimodal distribution of diameters, where the mean bubble diameter is less than 1 μm. In some embodiments, any of the compositions produced by the apparatuses and methods described herein include nano-bubbles, but are free of micro-bubbles.
Particular embodiments of the subject matter have been described. Nevertheless, it will be understood that various modifications, substitutions, and alterations may be made.
This application claims priority to U.S. Provisional Application Ser. No. 63/150,973, filed on Feb. 18, 2021, the entire contents of which are hereby incorporated by reference.
Number | Date | Country | |
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63150973 | Feb 2021 | US |