Patent ID: 6283727
Filing Date: 2001-09-04
Classification: F04B

Abstract:
A metering pump, comprisinga housing;a pumping chamber within said housing;a diaphragm movable in said pumping chamber and separating the pumping chamber into a pumping side for receiving and discharging fluid to be pumped and a pressurizing side for receiving hydraulic oil under pressure to move the diaphragm;an inlet to said pumping side including a check valve for allowing a fluid to be pumped to flow into said pumping side and preventing flow from said pumping side through said inlet;an outlet from said pumping side including a check valve for allowing a fluid to be pumped to flow from said pumping side and preventing flow into said pumping side through said outlet;a hydraulic pump in said housing and having an actuating side and a hydraulic piston containing, hydraulic side;a port connecting said hydraulic side to said pressurizing side;a hydraulic oil reservoir in said housing and in fluid communication with said hydraulic side; anda bypass device in said housing and connected to said port and operable upon operation of said piston to receive a predetermined amount of hydraulic oil.