Helical screw rotor profiles
AssigneeIngersoll-Rand Company
InventorJames L. Bowman
Life of this patent
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Abstract
The invention concerns helical- or screw-type driving and driven rotors having lands and intervening grooves for coacting engagement, within a housing of a machine, such as a gas compressor or expander, the rotors having improved, more efficient, profiles. The profiles are defined with contiguous elliptic and involute sections to improve the pressure angle, and the profiles are configured to define rotor-to-rotor sealing surfaces in closure of a compressed gas pocket in which, the pocket gas pressure always urges or torques the driven rotor in the positive or forward-rotary direction.
Claims15
A rotor, having helical lands and intervening grooves rotatable about an axis for coacting engagement within a machine housing, with a cooperating, meshing rotor, in order that fluid admitted into such housing will be received in said grooves and, due to coacting mesh and rotation of said rotors, will have the pressure thereof altered, wherein:
- each of said grooves has a leading flank and a trailing flank, relative to a given rotary direction of said rotor;
- and
- said leading and trailing flanks of said grooves of said rotor are generally concave;
- said leading flank is made up of a circular arc at its root, followed by an involute intermediate portion, followed by an elliptical portion which is contiguous with an outermost tip of said rotor.
Dependencies are inferred from the claim text.