Patent ID: 8118052

Claim:
A method of forming a polyurethane foam from a resin component and an isocyanate component using at least one control valve controlling a flow rate of at least one of the resin component and the isocyanate component, the control valve having a housing defining an inlet chamber and an outlet chamber spaced from each other with the housing receiving one of a plurality of interchangeable flow control devices each configured to define a fluid passage in fluid communication with the inlet and outlet chambers and each configured to provide a different selected range of flow rates through the flow control device, said method comprising: connecting lines having at least a 1 inch diameter to the housing at the inlet chamber and at the outlet chamber; coupling a source of gas pressure to the line having at least a 1 inch diameter at the inlet chamber; pressurizing the at least one of the resin component and the isocyanate component with the source of gas pressure to move the at least one of the resin component and the isocyanate component through the line having at least a 1 inch diameter at the inlet chamber and through the control valve at between 5 and 70 gallons per minute; coupling one of the plurality of interchangeable flow control devices with the housing to limit the flow rate through the housing to be within one of the selected ranges of flow rates; and adjusting the flow control device relative to the housing to vary the fluid communication between the fluid passage and at least one of the inlet and outlet chambers to control the flow rate of the at least one of the resin component and the isocyanate component.