Patent ID: 7404916

Claim:
A process for producing a cellular or compact polyurethane molding comprising: a) conveying at least one isocyanate component and at least one polyol component by a metering machine into a mixing head via component lines; b) mixing the isocyanate and polyol components in a mixing chamber to form a polyurethane reaction mixture; c) discharging the polyurethane reaction mixture from the mixing chamber into a mold; d) registering pressure of the isocyanate and polyol components by means of a pressure transducer in each of the component lines; e) transmitting the pressures registered in d) to a monitoring device to form transmitted pressure profiles; f) comparing the transmitted pressures profiles with corresponding reference pressure profiles stored in the monitoring device; g) signalling a malfunction in the event that at least one of the transmitted pressure profiles deviates from the corresponding reference pressure profile beyond a predetermined tolerance threshold; h) metering of the isocyanate and ployol components into the mixing chamber is initiated and terminated by opening and closing of one or more slides associated with a nozzle of each of the component lines into the mixing chamber, the opening and closing of the slides effected hydraulically by opening and closing of associated hydraulic valves; i) transmitting opening and closing times of the hydraulic valves to the monitoring device; and j) assigning temporally the opening and closing times of the hydraulic valve to the transmitted pressure profiles in the monitoring device, so that the transmitted pressure profiles are temporally assigned to a start and a stop of a shot of polyurethane reaction mixture to the mold.