143609 ⎘
Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups , , , , , or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group or and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member the inner and outer member being in contact along more than one line or surface the vanes having the form of rollers, slippers or the like