"A rotary lobe blower, Roots Blower (Booster Pump) refers to a specific design of positive displacement compressor with two lobed impellers with a roughly figure "8" shape which are mechanically linked via gears such that they rotate in opposite directions. The figure "8" shape allows the impellers to be close to but never in contact with both each other and the pump walls at every position of their rotation. The close tolerances of the blower allow the impellers to move without a lubricant producing an oil free process flow. The machine has been modified and improved to include European and Asian designs with three lobe blowers that produce lower pulsations and lower noise.

Isaiah Davies invented the design principle of the rotary lobe blower (Booster Pump) in 1848, but it was some twenty years later before Francis and Philader Roots applied it in practice in the US, first as a water wheel in their woolen mill."

The above article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Roots Blower".