Inlet guide vanes provide an efficient method of turndown for centrifugal compressors. Energy savings can be realized compared to inlet throttling by butterfly valves. An inlet butterfly valve achieves turndown through an inlet pressure drop. Guide vanes not only provide the inlet pressure drop but also impart a whirl motion to the gas as it enters the compressor impeller. Since this whirl motion is in the rotational direction of the impeller, it reduces the amount of work the impeller is required to do on the gas. It is this whirl motion that results in energy savings at the design conditions.

16 inch Inlet Guide Vane Assembly