GB581444A - Improvements in or relating to pumps, fans and like machines for transmitting energy to fluids - Google Patents

Abstract

581,444. Helico-centrifugal pumps. GILL J. H. W. May 17, 1944, No. 9485. [Class 110 (i)] In a conical-flow pump or fan (particularly for high output against a low or moderate head) comprising an annular flow passage between a casing Hand a central core G of which part is constituted by a boss F carrying rotor blades E, the core has a surface conforming substantially to a'surface of revolution of " dolphin " shape (defined mathematically in the Specification) and the 'rotor blades are set in a divergent portion of the flow passage. The cross-sectional area of the flow passage is substantially uniform. In the form shown a set of guide vanes N is provided on the stationary part of he core G to convert the whirl energy of the fluid into pressure energy, but these may be replaced by an expanding passage or a volute chamber. The direction of fluid flow through the rotor is preferably inclined at about 20‹ to the axis., The pitch of the rotor blades decreases outwardly so that the product of pitch and radius increases slightly but .substantially uniformly; the projected circumferential blade width increases with the radius, but in decreasing proportion. The blades E may be integral with the boss F, or they may be fixed so that their angle can be adjusted slightly to accommodate different ranges of working conditions. To accommodate a large increase in head for a given output without change of speed, a second rotor may be provided in series with the main rotor, its blades being mounted on another section of the "dolphin "-shaped core ; this rotor is either separated from the main rotor by a vaned diffuser or is arranged to rotate in the opposite direction.