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US 3,939,036 AGranted
Heat exchangers and evaporators
AssigneeAustral-Erwin Engineering Co.
InventorRansome W. Erwin
Life of this patent
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AssigneeAustral-Erwin Engineering Co.
InventorRansome W. Erwin
Estimating the term…
The invention comprises a method of evaporating an aqueous solution containing dissolved solids or mineral salts without adherence of the solids or mineral salts to any surfaces contacting the aqueous solution which comprises the following steps: A. Flowing the aqueous solution as an outside or continuous medium, mixed with sufficient dispersed oil to form a continuous film on all preferentially oil wettable contacting surfaces, upwardly through a confined heating and vaporizing zone having therein contacting heating elements, the surfaces of which are of substantially zero water adsorbent polymeric fluorocarbon material and totally wetted with a film of oil, thereby converting a portion of the aqueous solution to water vapor and precipitated solids, and forming a mixture of oil, misty vapors, solids, and remaining aqueous solution; and B. Separating this mixture of oil, misty vapors, solids, and remaining aqueous solution (still the outside or continuous water medium) into components thereof in succeeding zones or chambers in which substantially all surfaces contacting these materials are preferentially oil wettable. The invention also relates to apparatus in which the above method may be carried out.
The method of evaporating an aqueous feed solution containing dissolved solids or mineral salts and separating the resulting product into individual components without adherence of the solids or mineral salts to any surfaces contacting the aqueous solution, said method being carried out in an evaporating and separating apparatus which comprises (1) an evaporating chamber including a confined heating and vaporizing zone having heating elements therein and (2) succeeding separating chambers or zones separate from the evaporating chamber said succeeding chambers or zones including separating zones for (a) misty vapors, (b) oily foam, (c) hot oil, (d) oily aqueous solution, and (e) oily aqueous solution solids-slurry;
In a system where mineralized water or any type of aqueous solution or mixture is heated and wherein solids are formed by such heat, the method of combining the resulting mixture with an oil type of liquid wherein the aqueous liquid is the continuous medium, providing preferentially oil wettable surfaces for all contacting surfaces, providing substantially zero water adsorbent polymeric fluorocarbon surfaces for all contacting heat transfer surfaces, and wherein such added oil is sufficient to form an oil film on all such contacting surfaces and sufficient to prevent any adherence of solids to said surfaces.
In a system for heating aqueous solutions subject to forming precipitated solids when heated, wherein the heat is applied by a preferentially oil wettable substantially zero water adsorbent polymeric fluorocarbon heat transfer surface in contact with the aqueous solution and wherein an oil type liquid such as a hydrocarbon is employed to form a film to prevent adherence of solids to said heating surface, the step of slightly roughening or etching said heating surface prior to use, such roughening or etching thereby appreciably enhancing its oil wettability when contacted with oil droplets while submerged in an environment of aqueous solution or any watery medium.
Dependencies are inferred from the claim text.