Method of cleaning fast setting material spray equipment

This application claims the benefit of U.S. Application Ser. No. 60/971,305 filed Sep. 11, 2007, the contents of which are hereby incorporated by reference. This application also claims the benefit of U.S. Application Ser. No. 61/047,482 filed Apr. 24, 2008, the contents of which are again hereby incorporated by reference.

Conventional solvents used to clean fast set pumping and spraying equipment while using polyurethanes, polyureas and the like include mineral spirits, xylene, acetone, N-butyl acetate, butyl cellosolve, butyl carbitol, N-butyl alcohol, methyl ethyl ketone (MEK), methyl iso-butyl ketone, Stoddard, glycol ether, N-methylpyrrolidone (NMP) and DynaSolve brand of solvent. Many of these materials have some toxicity associated with them.

A method of cleaning and flushing a fast-set material spray gun is disclosed which uses, in the preferred embodiment, a mixture of approximately 62.5% DMSO, 32.5% DBE and 5% water. This mixture is non-toxic when atomized and lowers the freezing point of the liquid to below 10° F. Because the solvent is mixed with the purge air and expelled from the gun in atomized form, it is important that a non-toxic solvent be utilized and also important that the freezing point of the mixture be low enough to allow use in colder climates without freezing.

These and other objects and advantages of the invention will appear more fully from the following description made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views.

FIG. 1 shows the preferred embodiment of an air purge gun for spraying the fluid utilizing the method of the instant invention with the gun not spraying.

FIG. 2 shows the preferred embodiment of an air purge gun for spraying the fluid utilizing the method of the instant invention with the gun spraying.

A method of cleaning and flushing a fast-set material spray gun 10 is disclosed which uses, in the preferred embodiment, a mixture 12 of approximately 62.5% DMSO (dimethyl sulfoxide), 32.5% DBE (dibasic esther) and 5% water. This mixture 12 is non-toxic when atomized and lowers the freezing point of the liquid to below 10° F. Because the solvent is mixed with the purge air 14 and expelled from the gun 10 in atomized form, it is important that a non-toxic solvent be utilized and also important that the freezing point of the mixture be low enough to allow use in colder climates without freezing.

It is contemplated that various changes and modifications may be made to the cleaning method without departing from the spirit and scope of the invention as defined by the following claims.