Importance

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Abstract

An apparatus for applying a chemical foam to a traveling substrate in which a plurality of shut-off valves are spaced along a foam conduit between a foam generator and an applicator head to form the conduit into isolated sections when the valves are simultaneously closed upon stoppage of the traveling substrate, thereby maintaining pressure differential along the length of the conduit in readiness for resumption of operation when the substrate resumes travel and the valves are opened. To avoid decomposition of the foam in the applicator head during stoppage, a small by-pass conduit is connected to the valved conduit upstream and downstream of the valves to allow a small quantity of foam to continue to flow to the applicator head during stoppage of the substrate. A discharge valve at a discharge outlet of the applicator head opens during substrate stoppage to allow foam to discharge from the applicator head and maintain circulation of foam therein. The discharged foam is either returned directly to the generator for recycling or is fed selectively to one or the other of a pair of settling tanks until that settling tank is full, at which time the foam is directed to the other settling tank and the foam in the first settling tank is allowed to decompose to a liquid, following which it is recycled to the generator for regeneration and recycling through the apparatus.

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First Claim