HEATING OIL PUMP FOR SELECTIVE ONE OR TWO-LINE OPERATION

摘要

AbstractA heating oil pump is designed for selective one or two-lineoperation. Between the suction side (12) and return side (17),there is a connecting passage (23) which can be closed by a closuremember (Z4) during two-line operation. The latter is displaceablefrom a closed to an open position during insertion of the plug by anactuating element projecting into the insertion path of the plug (27)and back to the closed position by a return spring during removal ofthe plug. This provides an automatic change-over without the needfor the return pressure to be higher than the suction pressure.