Positive displacement transfer gear pump for molten metal

Abstract

A self-cleaning transfer gear pump for transferring molten metal includes the following features: a transfer conduit extends upward from an outlet of a base, two rotatable gears are formed of refractory material and disposed in the gear chamber and engage each other during rotation. A boss functioning as a bearing extends from the drive gear and is adapted to be received in an opening in the base. A shaft is fastened at a lower end to the drive gear. A filter is fastened to the base so as to cover the inlet and prevents particles and objects in the molten metal from entering the gear chamber. In operational mode, a motor rotates the shaft and the drive gear whereby the drive gear and the second gear engage each other while being rotated so as to positively displace molten metal from the inlet to the outlet and along the transfer conduit to the remote location. In self-cleaning mode, the motor rotates the shaft and the drive gear effectively to draw molten metal from the transfer conduit by positive displacement, through the outlet, and toward the inlet therefore cleaning the filter by removing the particles adhering to the filter. Also included are a system with optional filter and optional self-cleaning mode but including an inlet portion of a die casting machine, and a method for operating the gear pump. A flow sensor may be used to transmit pulses into and from the transfer conduit so as to enable determination of a volume of molten metal being charged. The control of the molten metal volume being charged is not solely controlled by the flow sensor.