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US 5,422,043 AGranted
Diffuser and diffusing method using dual surface tensions
OwnerWilliam A. Burrisinventor
Life of this patent
Estimating the term…
Abstract
A diffuser for dispersing gas bubbles into a liquid is formed of gas permeable material having a high surface tension at an interface with the liquid and a low surface tension in a region inward from the interface. The upstream region with the low surface tension resists liquid backflow, and the high surface tension of the interface keeps the bubbles small as they depart from the diffuser and enter the liquid.
Claims30
A diffuser for dispersing gas bubbles into a liquid, said diffuser comprising:
- a. a gas permeable upstream layer arranged to afford low pressure resistance to throughflow of gas toward said liquid;
- b. the upstream layer being formed of a low surface tension material with fine enough pores to have a high resistance to backflow of said liquid.
- c. a thin, gas permeable interface layer disposed downstream of said upstream layer between said upstream layer and said liquid, said interface layer also being arranged to afford low pressure resistance to throughflow of gas toward said liquid;
- d. said interface layer being formed of a material having a surface tension substantially higher than the low surface tension material of the upstream layer;
- and
- e. the surface tension of the interface layer being high enough for keeping the size of the bubbles substantially smaller than the bubbles would be if they formed on and departed from the low surface tension layer.
3 more elements
A diffuser comprising:
- a. a pair of gas permeable layers juxtaposed to allow gas to flow first through a gas side layer and second through a liquid side layer to be dispersed as bubbles delivered to a liquid from the liquid side layer;
- b. the gas side layer having a high resistance to backflow of said liquid;
- c. the gas side layer having a low surface tension;
- d. the liquid side layer being thin and having a surface tension substantially higher than said low surface tension, for keeping the size of said bubbles substantially smaller than said bubbles would be if they entered said liquid directly from said low surface tension material of the gas side layer;
- and
- e. said layers being thin enough to afford low pressure resistance to gas flow.
3 more elements
A method of diffusing gas bubbles into a liquid, said method comprising:
- a. pumping gas through a permeable material having a low surface tension and a high resistance to liquid flow in a direction counter to the flow of said gas;
- b. dispersing said gas through a layer of porous material disposed adjacent a downstream side of the permeable material, the porous material having a higher surface tension than said low surface tension permeable material so that small bubbles of said gas form on and depart from said higher surface tension material into said liquid;
- and
- c. making said lower and higher surface tension materials thin enough to form low pressure resistance to gas flow through both materials.
1 more element
A diffuser for dispersing a gas flow into bubbles directed into a liquid, said diffuser comprising:
- a. a gas inflow side of said diffuser being formed of a permeable material having a low surface tension and small pores forming a high resistance to backflow of liquid;
- b. a gas outflow side of said diffuser being formed of a separate porous material disposed adjacent the inflow side material and having a surface tension at least several dynes/cm higher than said low surface tension so that bubbles forming on and departing from said higher surface tension surface of the outflow side material are kept to a small size as they enter said liquid;
- and
- c. said diffuser being thin enough to afford a low pressure resistance to gas flow through both materials.
1 more element
A diffuser for dispersing a gas flow into bubbles directed into a liquid containing water, said diffuser comprising:
- a. a gas inflow side of said diffuser being formed of a spun-bonded, permeable fabric of resin material having a low surface tension and small pores less than one micron in diameter forming a high resistance to backflow of liquid;
- b. water being adsorbed on a gas outflow side of said permeable fabric material so that the surface tension of the gas outflow side of said permeable fabric material is at least several dynes per centimeter higher than the low surface tension of the gas inflow side of said permeable fabric material so that bubbles forming on and departing from said higher surface tension surface are kept to a small size as they enter said liquid;
- and
- c. said permeable fabric material being thin enough to afford a low pressure resistance to gas flow through the diffuser.
1 more element
Dependencies are inferred from the claim text.