Patent ID: 8156889

Claim:
An apparatus for dispensing a foamed material onto a substrate surface, comprising: a mixing device adapted to be in fluid connection with at least two sources of material components and including a mixing unit for mixing the material components fed from the two sources to form a free-flowing, foamable dispensing material, a dispensing head in fluid communication with the mixing device and including an exit opening defining a discharge cross-section producing a flow resistance to the dispensing material flowing through the discharge cross-section, the exit opening also defining a dispensing region located downstream in a direction of flow from the discharge cross-section and an upstream region located upstream in a direction of flow from the discharge cross-section, and a first feed pump for generating a pressure differential between the mixing device and the dispensing region, wherein the discharge cross-section is dimensioned to maintain a pressure of the dispensing material located in the upstream region such that the dispensing material in the upstream region exhibits a first foaming rate which is less than 10% of a second foaming rate occurring at the end of the foaming process following discharge from the exit opening, and wherein the dispensing head also includes at least one second feed pump.