Device and method for generating micro bubbles in a liquid using hydrodynamic cavitation

• US 20060027100A1
• Filed: 10/05/2005
• Published: 02/09/2006
• Est. Priority Date: 06/13/2003
• Status: Active Grant

• Current Assignee: Arisdyne Systems Incorporated
• Original Assignee: Five Peaks Technology LLC
• Inventors: Kozyuk, Oleg V.
• Granted Patent: US 7,338,551 B2
• Time in Patent Office: Days
• US Class Current: 95/260
• CPC Class Codes: B01F 23/232 using flow-mixing means for introducing the gases, e.g. baffles
• CPC Class Codes: B01F 23/2373 for obtaining fine bubbles, i.e. bubbles with a size below 100 µm
• CPC Class Codes: B01F 25/3121 with additional mixing means other than injector mixers, e.g. screens, baffles or rotating elements
• CPC Class Codes: B01F 25/31241 the main flow being injected in the circumferential area of the venturi, creating an aspiration in the central part of the conduit
• CPC Class Codes: B01F 25/31242 the main flow being injected in the central area of the venturi, creating an aspiration in the circumferential part of the conduit B01F25/31243 takes precedence
• CPC Class Codes: B01F 25/433 Mixing tubes wherein the shape of the tube influences the mixing, e.g. mixing tubes with varying cross-section or provided with inwardly extending profiles
• CPC Class Codes: B01F 25/4335 Mixers with a converging-diverging cross-section
• CPC Class Codes: B01F 25/434 Mixing tubes comprising cylindrical or conical inserts provided with grooves or protrusions

Abstract

A device and method for generating micro bubbles in a liquid. The method comprises the steps of: providing a flow-through channel containing at least two local constrictions of flow therein; passing the liquid at a velocity of at least at least 12 m/sec through a first local constriction of flow to create a first hydrodynamic cavitation field downstream from the first local constriction of flow; introducing a gas into the liquid in the first local constriction of flow, thereby creating gas-filled cavitation bubbles; collapsing the gas-filled cavitation bubbles formed in the first hydrodynamic cavitation field to dissolve the gas into the liquid, thereby forming a gas-saturated liquid; passing the gas-saturated liquid through a second local constriction of flow to create a second hydrodynamic cavitation field downstream from the second local constriction of flow; and extracting the dissolved gas from the gas-saturated liquid, thereby generating micro bubbles in the liquid.

Claims

1. A method of generating micro bubbles in a liquid comprising the steps of:

providing a flow-through channel containing at least two local constrictions of flow therein, the at least two local constrictions include a first and second local constrictions of flow;

passing the liquid at a velocity of at least at least 12 m/sec through the first local constriction of flow to create a first hydrodynamic cavitation field downstream from the first local constriction of flow;

introducing a gas into the liquid in the first local constriction of flow, thereby creating gas-filled cavitation bubbles;

collapsing the gas-filled cavitation bubbles formed in the first hydrodynamic cavitation field to dissolve the gas into the liquid, thereby forming a gas-saturated liquid;

passing the gas-saturated liquid through the second local constriction of flow to create a second hydrodynamic cavitation field downstream from the second local constriction of flow; and

extracting the dissolved gas from the gas-saturated liquid, thereby generating micro bubbles in the liquid.

2. The method of claim 1, wherein the first collapsing step occurs upon reaching an elevated static pressure zone created by the second local constriction of flow.

3. The method of claim 1, wherein the extracting step occurs upon reaching a vacuum zone created in the second hydrodynamic cavitation field.

4. The method of claim 1, wherein the gas is introduced into the liquid in a region of reduced liquid pressure in the first local constriction of flow.

5. The method of claim 1, wherein the gas is introduced at a gas flow rate sufficient to control the collapse of the cavitation bubbles formed in the first hydrodynamic cavitation field.

6. The method of claim 5, wherein a ratio of the liquid flow rate to the gas flow rate is at least about 10.

7. The method of claim 1, wherein the gas micro bubbles generated downstream from the second local constriction of flow are one or both of, smaller in size, and more uniform, than the cavitation bubbles formed in the first hydrodynamic cavitation field.

8. The method of claim 1, wherein the cross-sectional area of one or both of, the first local constriction of flow and the second local constriction of flow, is less than about 0.6 times the major diameter of the cross-section of the flow-through channel.

9. A method of generating micro bubbles in a liquid, comprising the steps of:

feeding the liquid into a flow-through channel at a first flow-rate, the flow-through channel including at least two cavitation generators, where a first cavitation generator is located upstream of a second cavitation generator;

introducing a gas into the first cavitation generator at a second flow rate;

flowing the liquid and the gas into the first cavitation generator at a velocity of at least 12 m/sec, thereby generating cavitation bubbles in the liquid in a first hydrodynamic cavitation field located downstream from the first cavitation generator;

at least partially squeezing the cavitation bubbles in an elevated static pressure zone, thereby dissolving the gas into the liquid; and

flowing the liquid containing the dissolved gas into the second cavitation generator at the minimum velocity, thereby extracting the dissolved gas from the liquid and generating micro bubbles in a second hydrodynamic cavitation field located downstream from the second cavitation generator;

wherein the micro bubbles are one or both of, smaller in size, and more uniform, than the cavitation bubbles.

10. The method of claim 9, wherein at least one of the cavitation generators includes a baffle.

11. The method of claim 9, wherein a ratio of the liquid volumetric flow rate to the gas volumetric flow rate is at least about 10.

12. The method of claim 9, wherein at least partially squeezing the cavitation bubbles in an elevated static pressure zone occurs downstream of the first cavitation generator and upstream of the second cavitation generator.

13. The method of claim 9, wherein the cavitation generators each include a local constriction of flow.

14. The method of claim 13, wherein the local constriction of flow includes one or more of, a baffle, an orifice, a nozzle, and a Venturi tube.

15. The method of claim 13, wherein the cross-sectional area of at least one of the local constrictions of flow is less than about 0.6 times the major diameter of the cross-section of the flow-through channel.

16. A method of generating micro bubbles in a liquid comprising the steps of:

feeding the liquid through a flow-through channel internally containing at least two local constrictions of flow, the at least two local constrictions of flow including a first local constriction of flow and a second local constriction of flow positioned downstream from the first local constriction of flow;

passing the liquid at a velocity of at least 12 m/sec through the first local constriction of flow to create a first hydrodynamic cavitation field downstream from the first local constriction of flow;

creating cavitation bubbles in the first hydrodynamic cavitation field;

introducing gas into the flow-through chamber in the upstream local constriction of flow;

upon reaching an elevated static pressure zone created by the second local constriction of flow, collapsing the cavitation bubbles created in the first hydrodynamic cavitation field to dissolve the gas into the liquid, thereby forming a gas-saturated liquid;

maintaining a ratio of the liquid volumetric flow rate to the gas volumetric flow rate at a minimum ratio of at least about 10 to, at least in part, control the collapse of the cavitation bubbles;

passing the gas-saturated liquid flow at a velocity of at least 16 m/sec through the second local constriction of flow to create a second hydrodynamic cavitation field downstream from the second local constriction of flow; and

upon reaching a vacuum zone created in the second hydrodynamic cavitation field, extracting the dissolved gas from the gas-saturated liquid to generate micro bubbles in the liquid.

17. The method of claim 16, wherein the gas is introduced into the liquid in a region of reduced liquid pressure in the first local constriction of flow.

18. The method of claim 16, wherein the local constriction of flow includes one or more of, a baffle, an orifice, a nozzle, and a Venturi tube.

19. The method of claim 16, wherein the cross-sectional area of one or both of, the first local constriction of flow and the second local constriction of flow, is less than about 0.6 times the major diameter of the cross-section of the flow-through channel.

20. The method of claim 16, wherein the gas micro bubbles generated downstream from the second local constriction of flow are one or both of, smaller in size, and more uniform, than the cavitation bubbles formed in the first hydrodynamic cavitation field.