Patent ID: 8192155
Filing Date: 2012-06-05
Classification: F04D,Y10S

Abstract:
1. A multi-stage partial emissions pump comprising a first stage impeller, a coaxially mounted final stage impeller, a first stage inlet liner, a first stage casing liner, one or more first stage discharge outlets, a final stage casing liner, a cover, one or more final stage discharge outlets, an interstage delivery channel liner, for each of the first stage discharge outlets an associated delivery channel formed in the interstage liner, and an outer pressure shell, wherein: the first stage impeller is enclosed in a first stage cavity formed between the first stage inlet liner and the first stage casing liner, the first stage inlet liner being in fluid communication with a first stage inlet; the final stage impeller is enclosed in a final stage cavity formed between the final stage casing liner and the cover, the final stage casing liner being in fluid communication with a final stage inlet; the first and final stage discharge outlets are sized so as to restrict outflows of fluids from the first and final stage cavities during each revolution of the first and final stage impellers to be small percentages of volumes of the first and final stage cavities, respectively; each of the first stage outlets includes a nozzle for discharging fluid into a straight conical diffuser formed in the first stage casing liner and penetrating an outer surface of the first stage casing liner; each of the delivery channels is positioned to receive the fluid discharged from the conical diffuser of the associated first stage outlet and convey the fluid to the final stage inlet; and the sum of the cross sectional areas of all said delivery channels taken on a radial plane intersecting the delivery channels is less than the sum of cross sectional areas of all non-channel areas within all boundaries of the delivery channels on said plane.