Method of recycling powder coatings in a plural coating operation

Claim 1

A method of painting successive articles with powder paint which comprises the steps of: a. establishing a first spray zone of powder paint for applying powder paint on each of the successive articles; b. moving articles successively through the first spray zone so as to have a first coat of powder paint placed on each article; c. fusing the first coat of powder paint on each of the articles after the articles have been moved through the first spray zone thereby to form an undercoat on each of the articles; d. establishing a second spray zone of powder paint for applying a second coat of powder paint on each of the successive articles; e. spraying a powder paint having a desired color on each of the successive articles passing through the second spray zone; f. from time to time or from article to article changing the desired color sprayed in the second spray zone so that the successive articles are generally not of the same color; g. moving successive articles through the second spray zone to receive a coating of a second powder paint having a color selected for that article; h. fusing the second coating of powder paint on each of the successive articles after the articles have been moved through the second spray zone thereby to form a top coat on each of the successive articles; i. collecting any over sprayed powder paint from the second spray zone, the second over sprayed paint being nonhomogeneous in color because it contains a mixture of the top coat color powders used in the second spray zone; j. using the collected second over sprayed powder paint in the first spray zone as an undercoat powder paint; k. collecting the overspray of the first spray zone and respraying in the first spray zone.

Claim 2

A method of painting successive articles with powder paint which comprises the steps of: a. establishing a first spray zone of powder paint for applying powder paint on each of the successive articles; b. moving articles successively through the first spray zone so as to have a first coat of powder paint placed on each article; c. fusing the first coat of powder paint on each of the articles after the articles have been moved through the first spray zone thereby to form an undercoat on each of the articles; d. establishing a second spray zone of powder paint for applying a second coat of powder paint on each of the successive articles; e. spraying a powder paint having a desired color on each of the successive articles passing through the second spray zone; f. from time to time or from article to article changing the desired color sprayed in the second spray zone so that the successive articles are generally not of the same color; g. moving successive articles through the second spray zone to receive a coating of a second powder paint having a color selected for that article; h. fusing the second coating of powder paint on each of the successive articles after the articles have been moved through the second spray zone thereby to form a top coat on each of the successive articles; i. collecting any over sprayed powder paint from the second spray zone, the second over sprayed paint being nonhomogeneous in color because it contains a mixture of the top coat color powders used in the second spray zone; j. using the collected second over sprayed powder paint in the first spray zone as an undercoat powder paint; k. collecting the overspray of the first spray zone and respraying in the first spray zone.