US Patent 7094042 Dual-inlet gear pump with unequal flow capability

A dual-inlet gear pump includes a drive gear and a driven gear. The invention utilizes the discovery that the drive gear will typically move a higher flow volume than does the driven gear, particularly when the fluid being moved is an air/oil mixture. The present invention takes advantage of this discovery to communicate a first higher expected flow source to the drive gear, and to separately communicate a second, relatively lower expected flow rate to the driven gear. A particular application is in a scavenging pump for a jet engine.