A KAY Rotary Twin Lobe Compressor (Roots Blowers) is a positive displacement, constant volume machine which operates against varying pressure. The two “8” shaped impellers (involute design) which are mounted on parallel shafts, rotate in opposite direction and with every movement of the impeller across the compressor inlet, a definite volume of air is trapped and carried across the casing to the compressor outlet where this air is discharges.

With a constant speed operation, the displaced volume is essentially the same a constant pressure, temperature or barometric pressure. Increasing the speed of the KAY compressor against a constant pressure increases the volume of air delivery. The timing gears fitted in a KAY compressor control the relative position of the impellers to one another and maintain small but definite clearances. This allows operation without the need for lubrication inside the air casing.