Patent ID: 9714655
Date: 2017-07-25
CPC Classifications: F01C,F04C

Claim:
1. A method of designing rotors for a rotary device having a lobe rotor and a recess rotor coupled for intermeshing rotation, wherein the lobe and recess rotors intermesh in such a manner that on rotation thereof, a transient chamber of variable volume is defined, the transient chamber having a progressively increasing or decreasing volume between a recess surface of a recess of the recess rotor and a lobe surface of a lobe of the lobe rotor, wherein at least during part of a cycle of rotation the transient chamber is formed entirely between the lobe surface and the recess surface, wherein the recess and lobe surfaces are contoured such that during passage of the lobe through the recess, the recess surface is continuously swept, by both a tip of the lobe and a movable location on the lobe, wherein, in use, the transient chamber functions as an expansion or compression chamber of the rotary device for compression or expansion of a working fluid the method comprising: determining the geometry of the or each lobe in dependence on an inner radius of the lobe ρLi, an outer rotor radius at the tip of lobe ρLo, and a circular arc segment AI of radius RI defining a bulk of the lobe and the an outer radius of the recess rotor ρPo, wherein the geometry of the or each lobe is, in addition, determined by a circular arc segment Ac of radius Rc wherein the arc segment AI of the radius RI defines the bulk of the lobe from its tip to an inflection point and the circular arc segment Ac of the radius Rc defines a base of the lobe connecting between the are segment AI and the core of the lobe.