BRACKET AS 1712516 - Caterpillar

Illustration 1 g01389207
Dual displacement metering pump (1) Larger displacement gerotor (2) Pressure controlled logic valve (3) Smaller displacement gerotorThe dual displacement metering pump operates in the same way as the standard displacement metering pump. Refer to System Operation, KENR5215, "Metering Pump (HMU)" for the operation of a standard displacement metering pump.The dual displacement metering pump uses two gerotors and a pressure controlled logic valve. The pressure controlled logic valve (2) makes the selection between the two gerotors.The pressure controlled logic valve is spring return valve that will return to the displacement gerotor (3) when the inlet pressure falls below 800 kPa (120 psi). The smaller displacement of gerotor (3) makes manual steering easier for an unpowered machine.When the inlet pressure is above 800 kPa (120 psi), the pressure controlled logic valve (2) is shifted in order to combine the volume from the large gerotor (1) and the volume from the smaller gerotor (3). The total displacement of the pump is now the sum of gerotor (1) and gerotor (3). The number of turns that are required to turn from the left stop to the right stop is reduced.