Patent ID: 8287232
Filing Date: 2012-10-16
Classification: F04D,F05D

Abstract:
1. A centrifugal compressor configured to provide a flow of recirculated air for surge control, the compressor comprising: a housing defining an axial inlet passage, a radial diffuser passage, an exit, and at least one injection port, each injection port extending to an outlet on an inner surface of the inlet passage; a compressor wheel defining a plurality of blades, each blade having a leading edge adjacent the inlet passage and a trailing edge adjacent the diffuser passage, the compressor wheel rotatably mounted in the housing such that the compressor wheel is configured to receive air flowing generally axially in the inlet passage at the leading edges of the blades and deliver the air from the trailing edges of the blades in a generally radial direction to the exit, the leading edges being configured proximate the outlet of the injection port; a recirculation passage fluidly connected to the exit and configured to receive a flow of compressed air from the compressor wheel and deliver the compressed air through the injection port to the leading edges of the blades of the compressor wheel; and an adjustable flow control device configured to control the flow of the compressed air through the recirculation passage to the injection port to thereby control a surge characteristic of the compressor, wherein the flow control device includes first and second valves in a fluidly parallel configuration, each of the valves being independently controllable between open and closed positions for controlling a respective flow of compressed air through each valve, such that the flow control device is configured to provide at least three different rates of flow of the compressed air to the at least one injection port, and wherein the flow control device is configured to combine the two flows of compressed air downstream of the valves and upstream of the at least one injection port.