US 4,408,953 A · High efficiency centrifugal pump

Abstract

A high speed fuel pump for a gas turnbine engine has a positively-driven shroud (28) positioned between a main impeller (14) and the wall of a pumping cavity (12) to reduce impeller drag. The shroud is formed by a first disc (30) having a boost impeller (36) connected to its central hub portion 30a and a second disc (32) having a gear (32b) carried by its central hub portion (32a). The main drive shaft assembly (24), to which the main impeller is connected, carries a gear (64) which meshes with gear (62) mounted upon a shaft (58). The shaft (58) also carries a gear (56) which meshes with the gear 32b. The gears are sized so that the shroud is driven at one-half the speed of the main impeller in order to maximize impeller drag reduction and enhance pumping capability when severe inlet conditions are present at the pump inlet (10).

Claims4

Dependent claims

In a high speed centrifugal fuel pump of the type having:

a housing with a pumping cavity therein, a main impeller mounted for rotation in the pumping cavity and a drive shaft assembly mounted in the housing for rotation and operatively connected to the main impeller for concurrent rotation at the same RPM, a shroud mounted for rotation in the housing surrounding the impeller in closely spaced relationship thereto, the improvement comprising:
a gear mounted on the drive shaft assembly;
a gear on the shroud;
two integral interconnecting gears in respective meshing engagement with the first and second mentioned gears and sized to rotate the second mentioned gear at one-half the RPM of the first mentioned gear whereby the shroud is rotated at an RPM one-half that of the drive shaft assembly;
and seal means to isolate the gears from oil and fuel to minimize drag on the rotating gears.

2 more elements

Dependencies are inferred from the claim text.

High efficiency centrifugal pump

Life of this patent

High efficiency centrifugal pump

Life of this patent

Abstract

Claims4