Rotary blower with an abradable coating

摘要

An improved rotary blower (11) with an abradable coating (61) with a maximum hardness value of 2H on a pencil hardness scale. The coating material is a blend or mixture of preferably an epoxy-polymer resin matrix with a solid lubricant. The solid lubricant preferably is graphite. The improved abradable coating provides essentially zero clearance to increase the volumetric efficiency of a Roots type rotary blower.