Patent ID: 6471006
Filing Date: 2002-10-29
Classification: D21G

Abstract:
A multipressure system for hydraulic roll control in a papermaking machine, comprising:an oil tank having a single compartment; at least one low pressure pump which draws oil from the oil tank compartment; a first manifold carrying oil from the at least one low pressure pump to a plurality of points of service, the points of service including a plurality of roll bearing lubrications or drive gearbox lubrications; at least one high pressure pump connected to receive oil from the at least one low pressure pump and to elevate the pressure of the oil received therefrom, oil being delivered from the high pressure pump to pressure-loaded zones of a hydraulic roll; at least one pressure regulator positioned between the at least one low pressure pump and the at least one high pressure pump set to regulate oil pressure supplied to the high-pressure pump to between 20 bar and 30 bar; and at least one filter and at least one cooler positioned after the at least one low pressure pump and before the at least one high pressure pump, and wherein oil from the points of service is arranged to pass back to the oil tank, wherein the multipressure system is implemented as a single low-pressure circuit and wherein oil flows directly to the points of service essentially at the line pressure of the low-pressure circuit or at a pressure level higher than that of the primary circuit by virtue of stepwise elevating the line pressure with the help of the at least one high-pressure pump.