Patent ID: 6900164

Claim:
An in-situ foaming drain cleaner, comprising: a first aqueous liquid, having a viscosity of at least about 150 cP, said first liquid comprising an oxidant, wherein the oxidant is a hypochlorite present in the first aqueous liquid in an amount of about 1-10 percent by weight based on a weight of the first aqueous liquid; a second aqueous liquid, having a viscosity of between about 0 and 20 cP the second liquid comprising a gas-generating agent, wherein the gas-generating agent is a peroxide present in the second aqueous liquid in an amount of about 0.1 to 15 percent by weight based on a weight of the second aqueous liquid; a hydroxide pH-adjusting agent mixed with at least one of the aqueous liquids, wherein the hydroxide is present in an amount of between about 0.5 and 10 percent by weight based on a weight of the first aqueous liquid; a surfactant mixed with at least one of the aqueous liquids; and sodium chloride present in an amount less than about 25 percent by weight based on a weight of the second aqueous liquid; wherein the first and second aqueous liquids are separately maintained prior to forming an admixture during delivery to a drain to be treated, whereupon the admixture generates a foam of sufficient stability for cleaning efficacy; wherein an initial phase of foam is generated at a rate of between about 150 and 800 ml/sec, the initial phase lasting about 10 seconds; wherein a second phase of foam is generated at a rate between about 0 and 150 ml/sec; wherein said foam is characterized by a density of at least about 0.1 g/ml; wherein said foam is characterized by a foam to liquid ratio of greater than about 3:1; wherein said foam is characterized by a half life of greater than about thirty minutes; wherein the oxidant is present in a molar excess over the gas generating agent in a range of about 6:1 to 2:1.