Foam producing method

Claim 1

In a method for successively dispensing discrete quantities of an urea formaldehyde foamed resin mixture having as constituents a resin component and a hardener component, including the steps of causing one of said components to foam, supplying the foamed component and the other component independently and under pressure to a mixing chamber, mixing said components in said chamber, and thereafter dispending a quantity of foamed resin mixture from said chamber through an outlet duct the length of which is of the same order as the dimensions of said chamber; the improvement which comprises the sequential steps of: (a) mixing said components in said chamber by spraying the unfoamed component onto the foamed component so that the cellular structure of the foamed component is retained; (b) dispensing a quantity of foamed resin mixture through said outlet duct; (c) interrupting the supply of said components to the mixing chamber; (d) sweeping the mixing chamber and the outlet duct to remove therefrom residue of said mixture; and (e) restoring the supply of said components to the mixing chamber so as to dispense a further quantity of the foamed resin mixture through said outlet duct.