Abstract: The disclosure illustrates a range improvement feature for a compressor wheel in which a chamber adjacent the inlet is separated from the outer periphery of the impeller wheel vanes by a wall through which communication is established between the chamber and the impeller wheel. Communication is provided by either an annular slot or a series of radial holes. The feature may be used on single stage or multistage compressors. The area of the communication is such that at high rpm, and/or high flow, flow is from the chamber inward and at lower flows the flow is from the impeller wheel outward. This bidirectional flow improves the range over twhich the compressor may operate without encountering surge.

Abstract: The disclosure illustrates a range improvement feature for a compressor wheel in which a chamber adjacent the inlet is separated from the outer periphery of the impeller wheel vanes by a wall through which communication is established between the chamber and the impeller wheel. Communication is provided by either an annular slot or a series of radial holes. The feature may be used on single stage or multistage compressors. The area of the communication is such that at high rpm, and/or high flow, flow is from the chamber inward and at lower flows the flow is from the impeller wheel outward. This bidirectional flow improves the range over which the compressor may operate without encountering surge.

Abstract: An impeller for a centrifugal impeller comprising a disc portion, a coaxial hub portion having a longitudinal through-bore by which the impeller is mounted on a rotatable shaft, and a plurality of blades in any one of several forms. The tip of each blade is curved in a direction opposite to the rotation of the impeller more than the rest of the blade. The radius of the tip curve decreases uniformly toward the radially outer end of the blade. This tip treatment produces improved isentropic efficiency.