A centrifugal compressor includes a casing, a first impeller, a motor, a cooling medium delivery structure, a shaft, and a first bearing. The casing has a first inlet portion and a first outlet portion. The first impeller is attached to the shaft and disposed between the first inlet portion and the first outlet portion. A first axial gap exists between the first impeller and the casing. The shaft is rotatably supported and axially moveable with respect to the casing by the first bearing. The motor is arranged inside the casing to rotate the shaft. The cooling medium delivery structure is configured to vary a supply of a cooling medium to the casing.

An impeller clearance control apparatus for a centrifugal compressor includes a sensor and a controller. The controller controls a supply of a cooling medium to the casing based on a value detected by the sensor.

A method of operating a chiller system includes receiving an input from at least one sensor associated with a compressor of the chiller system, determining that the compressor is experiencing a surge or rotating stall event, adjusting at least one operating parameter associated with a heat rejection heat exchanger of the chiller system in response to determining that the compressor is experiencing the surge or rotating stall event, and reducing a condenser saturation temperature by adjusting the at least one operating parameter.

A vacuum motor assembly that includes a motor comprising a drive shaft; an impeller having a plurality of impeller blades spaced radially around a center portion of the impeller. An impeller cover that forms an air channel is spaced around the impeller and the impeller cover includes a front portion; a back portion engaged to the front portion; and a back support. The drive shaft of the motor passes through the drive shaft receiving hole of the back support and engages with the impeller. A front surface of the impeller defines a vertical plane and a first air channel interior distance from the front portion inner surface to the vertical plane within the airflow channel is greater than a second air channel interior distance measured from a back portion inner surface to the same vertical plane.

Disclosed is an apparatus and method for surge prevention for a centrifugal compressor. An apparatus for surge prevention for a buffering vessel based centrifugal compressor according to the present invention includes a recycle pipe which connects a suction portion to a discharge portion of the centrifugal compressor, a cooler which cools compressed gas received according to an opening of a recycle valve disposed at the recycle pipe, a buffering vessel which stores the gas cooled by the cooler, and a compressor control unit which determines a surge occurrence condition to control opening and closing of the recycle valve and a buffer valve which is disposed at a rear stage of the buffering vessel.

The present application provides an inlet bleed heat control system for a compressor of a gas turbine engine. The inlet bleed heat control system provides an inlet bleed heat manifold and an ejector in communication with the inlet bleed heat manifold such that the ejector is in communication with a flow of compressor discharge air and a flow of ambient air.

A method for pressure and temperature control of fluid in a series of cryogenic compressors. An actual speed for each compressor and an actual inlet pressure and actual inlet temperature at entry are determined. The maximum speed for each compressor and a desired inlet pressure for the first compressor is provided. A speed index for each compressor is determined from the maximum speed and actual speed of each compressor. A proportional value is determined from the deviation of the actual and desired inlet pressure. A priority value is determined from the smaller of the proportional value and the smallest speed index. A desired inlet temperature for the first compressor and a desired speed for each compressor are determined from the priority value. The actual inlet temperature is adjusted to the determined desired inlet temperature and the actual speed for each compressor is adjusted to the determined desired speed.