GB223257A - Improvements in rotors for rotary compressors and the like - Google Patents

Abstract

223,257. Dehn, F. B., (Hill Engineering Co., Inc.). April 16, 1923. Pumps; milling-cutters.-A rotary compressor or pump comprises two toothed rotor members, one, a pinion rotor, inside and eccentric to the other, an annular rotor, and having one tooth less, one member driving the other, and the tooth contours being such that the teeth of the rotors may enclose a number of chambers which expand and contract during rotation and maintain a fluid tight contact between separate chambers. The tooth contours may be of a form 30<a> deprived by the envelope of a circle 28 the centre 29 of which moves on an oblate hypo-trochoid 30 traced by a point Z exterior to a circle B which rolls on a base circle A, Fig. VIII. The annular rotor may be made by means of a milling-cutter in the position of the circle 28, the axis 29 of which is rotated about an axis 9 at a speed proportional to the number of teeth on the annular rotor, for example, nine, while a blank to be cut is rotated about an axis 8 at a speed eight. By a similar arrangement in which the cutter and blank rotate at speeds eight and seven a trimming-die of eight tooth divisions is obtained and this may be used to cut a pinion rotor. The pinion may also be machined by milling-cutter blades 37 which are formed as shown in Fig. VI by mounting them in a ring 32<a> the centre 33 of which rotates eight times round an axis 32 while the ring 32<a> turns once on its own axis 33, a cutter 28<a> in this case being rotated on a fixed axis 29. Reference has been directed by the Comptroller to Specification 9359/15, [Class 110 (ii), Rotary engines &c.]