INTERNAL PRESSURE EXCLUSION MECHANISM FOR ELECTROMAGNETIC PUMP
Document Type and Number:
Japanese Patent JP3498275
PROBLEM TO BE SOLVED: To surely and quickly reduce residual pressure in stopping of a pump by forming a return flow path extending from the lower reaches than a delivery valve to the upper reaches of a suction valve and setting the return flow path to close, when a plunger stored in an enlarged space on the way thereto moves against a spring.
SOLUTION: An electromagnetic pump 1 causes volume change in a pump chamber 45 by reciprocating of an electromagnetic plunger and a piston, and a fuel oil sucked from a suction hole 48 is discharged by pressurization. In this case, a part of high-pressure oil is introduced to a high-pressure side space 79a of an internal pressure exclusion mechanism through a return flow path 76. And the plunger 79 is made to flow to the right against a spring 87 and a sheet 85 is brought in contact with a main body 19 so as to cut off an orifice 82. When operation of the electromagnetic pump is stopped, pressures of the high pressure-side space 79a and a suction-side space 79b become the same so that the plunger 79 is made to return to an original position by the spring 87 and fuel oil is made to flow to the suction side via the return path 76 so as to suddenly reduce an internal residual pressure.
December 05, 2003
July 06, 1995
NIPPON CONTROL KOGYO KK
F16K17/04; F16K17/04; (IPC1-7): F16K17/04