Algae resistant edge coating and method of forming same
A gas-liquid contact body for use in a gas-liquid contact apparatus is formed of a plurality of facially opposed corrugated sheets with the corrugations in alternate sheets being disposed in parallel to form a plurality of criss-crossing channels for gas and liquid. The contact body has an air inlet side including an air inlet portion which is coated with a water-impermeable hydrophilic material whose density on the surface of the sheets decreases from a maximum at the edge of the sheets downstream within the air inlet portion to leave progressively increasing areas of said sheet exposed to air.
1. A gas-liquid contact body for use in a gas-liquid contact apparatus, said contact body comprising a plurality of facially opposed corrugated sheets with the corrugations in alternate sheets being disposed in parallel to form a plurality of criss-crossing channels for gas and liquid, said contact body having an air inlet side including an air inlet edge and an inlet edge portion downstream of said edge, said air inlet edge portion being coated with a water-impermeable hydrophilic material whose density of coverage decreases from a maximum of said air inlet edge downstream, within said air inlet portion to expose progressively increasing areas of said sheets to the air.
2. A gas-liquid contact body as defined in claim 1 , wherein portions of said corrugated sheets in said inlet edge portion are essentially uncoated.
3. A gas-liquid contact body for use in a gas and liquid contact apparatus having a casing, a gas inlet side and a gas outlet side, said contact body comprising a plurality of corrugated sheets disposed in facially opposed relationship to one another and in substantially parallel relationship to one another and defining a gas inlet edge adapted to be positioned adjacent said gas inlet side of a casing, and a plurality of intersecting and intercommunicating passages allowing the passage of gas and liquid therethrough, the corrugations in each of said sheets extending at an angle to the main section of flow of the gas through the body with the corrugations in alternate strips being disposed at an angle to the corrugations in the adjacent strips, said sheets having a gas inlet edge and an inlet edge portion downstream of said edge being coated with a water-impermeable hydrophilic material whose density of coverage decreases from a maximum of said air inlet edge downstream, within said air inlet portion to expose progressively increasing areas of said sheets to the air.
4. A gas liquid contact body as defined in claim 3 wherein said coating includes a material selected from the group consisting of latex rubber, acrylic or plastic.
5. A gas-liquid contact body as defined in claim 3 , wherein portions of said corrugated sheets in said inlet edge portion are essentially uncoated.
6. The method of coating an air inlet edge portion of a contact body comprising a plurality of facially opposed corrugated sheets comprising the step of:
moving said contact body relative to a plurality of coating spray nozzles with said air inlet edge portion facing the nozzles,
positioning the nozzles at angles to the surface of the contact body; and
spraying coating material in droplet form towards said contact body and its air inlet portion,
whereby the density of the coating on the surfaces of the air inlet portion decrease from a maximum at the surface of the body facing the nozzles downstream within the air inlet portion to leave progressively increasing areas of said sheets exposed to air.
7. The method as defined in claim 6 , including the step of directing the nozzles at an angle to the surface of the contact body whereby predetermined portions of the surface of the corrugations are sprayed with coating and other portions are blocked from spray by adjacent corrugations.