Abstract: A control system is provided that can identify the occurrence of a single surge cycle in centrifugal compressor using various methods and devices. Once the occurrence of a single surge cycle is identified, the control system can take remedial action to respond to the surge cycle, such as by adjusting the position of a variable geometry diffuser, and restore the centrifugal compressor to stable operation.

Abstract: A compressor includes an inlet and the inlet includes a flange and an impeller eye. The flange is connected to a suction line that transfers a refrigerant into the compressor via the impeller eye. The refrigerant flows into the compressor with an amount of swirl and a pressure loss. The suction line includes a geometry that includes a constantly decreasing cross-sectional area in a direction towards the compressor. The geometry of the suction line is configured to reduce the amount of swirl and the pressure loss.

Abstract: A compressor includes an inlet and the inlet includes a flange and an impeller eye. The flange is connected to a suction line that transfers a refrigerant into the compressor via the impeller eye. The refrigerant flows into the compressor with an amount of swirl and a pressure loss. The suction line includes a geometry that includes a constantly decreasing cross-sectional area in a direction towards the compressor. The geometry of the suction line is configured to reduce the amount of swirl and the pressure loss.

Abstract: A compressor includes an inlet and the inlet includes a flange and an impeller eye. The flange is connected to a suction line that transfers a refrigerant into the compressor via the impeller eye. The refrigerant flows into the compressor with an amount of swirl and a pressure loss. The suction line includes a geometry that includes a constantly decreasing cross-sectional area in a direction towards the compressor. The geometry of the suction line is configured to reduce the amount of swirl and the pressure loss.

Abstract: A system for controlling a centrifugal gas compressor (108) in an HVAC, refrigeration or liquid chiller system (100) in which flow of gas through the compressor is automatically controlled to maintain desired parameters within predetermined ranges so as to prevent stall and surge conditions within the system. A variable geometry diffuser (119) in the compressor controls the refrigerant gas flow at the discharge of the compressor impeller wheel (201). This arrangement reduces mass flow, decrease/eliminate flow-reducing stall, and increases the operating efficiency of the compressor at partial load conditions. The variable geometry diffuser control in combination with a variable speed drive (VSD) (120) increases the efficiency of the compressor at partial system loads, and eliminates the need for pre-rotation vanes at the inlet of the centrifugal compressor.

Abstract: A control system is provided that can identify the occurrence of a single surge cycle in centrifugal compressor using various methods and devices. Once the occurrence of a single surge cycle is identified, the control system can take remedial action to respond to the surge cycle, such as by adjusting the position of a variable geometry diffuser, and restore the centrifugal compressor to stable operation.

Abstract: A system for controlling a centrifugal gas compressor (108) in an HVAC, refrigeration or liquid chiller system (100) in which flow of gas through the compressor is automatically controlled to maintain desired parameters within predetermined ranges so as to prevent stall and surge conditions within the system. A variable geometry diffuser (119) in the compressor controls the refrigerant gas flow at the discharge of the compressor impeller wheel (201). This arrangement reduces mass flow, decrease/eliminate flow-reducing stall, and increases the operating efficiency of the compressor at partial load conditions. The variable geometry diffuser control in combination with a variable speed drive (VSD) (120) increases the efficiency of the compressor at partial system loads, and eliminates the need for pre-rotation vanes at the inlet of the centrifugal compressor.

Abstract: A patient support apparatus which includes a firm body support portion constructed of foam, with the foam halving a first side for placement on a bed or gurney, and the second side upon which the body of the patient would be laid. The foam apparatus would include a principal upper torso support portion for supporting a patient generally from the top of the patient's head to the lower buttock region of the patient; first and second leg portions which are attachable to a lower edge of the principal body support portion for supporting the legs of the patient, and attachable arm portions secured to the side edges of the upper body support portion for accommodating the arms of the patient.

Abstract: A patient support apparatus which includes a firm body support portion constructed of foam, with the foam having a first side for placement on a bed or gurney, and the second side upon which the body of the patient would be laid. The foam apparatus would include a principal upper torso support portion for supporting a patient generally from the top of the patient's head to the lower buttock region of the patient; first and second leg portions which are attachable to a lower edge of the principal body support portion for supporting the legs of the patient, and attachable arm portions secured to the side edges of the upper body support portion for accommodating the arms of the patient.