Patent ID: 8512642

Claim:
An apparatus for producing a hard polyurethane foam by a froth process, comprising a foaming agent supply means that quantitatively supplies as a foaming agent an inert gas compressed to a predetermined pressure or liquefied and a foaming means that discharges a hard polyurethane foam obtained by forming a foaming polyol composition by mixing the inert gas and a polyol composition and then by mixing the foaming polyol composition with a polyisocyanate component, wherein the foaming agent supply means has a pressure-reducing valve that reduces and adjusts the pressure of the inert gas and a needle valve that adjusts the flow rate of the inert gas, the foaming means has a compression cylinder for compressing and supplying the polyol composition, an opening and closing valve that regulates the supply of the inert gas to the foaming means is provided between the foaming means and the foaming agent supply means, and a control device equipped with a laser sensor that senses the operation of the compression cylinder and a sequencer that controls an opening and closing operation of the opening and closing valve, wherein a pressure-holding valve that regulates the pressure of the inert gas to a constant pressure within the range of 6 to 6.5 MPa and a flowmeter that measures the flow rate of the inert as are provided between the pressure-reducing valve and the needle valve.