Centrifugal compressors can incorporate a side stream flow of intermediate pressure vapor between stages of that compressor. The side stream flow can be controlled by a side stream injection port controlled by a capacity control valve that has a curved surface facing a flow of refrigerant from the first stage to the second stage. The capacity control valve can allow or obstruct flow through the side stream injection port. The capacity control valve can extend and retract in a direction substantially perpendicular to the direction of flow from the first stage impeller to the second stage impeller. The side stream injection port and the capacity control valve can be ring-shaped. The side stream injection port and the capacity control valve can allow at least some of the side stream to be introduced on a side of the capacity control valve opposite the curved surface.

Apparatus is provided to proportionally actuate a valve, furthermore control actuation speed and/or torque. The valve can be actuated manually via an input signal provided by a plurality of controllers. The device has sensory control, wherein sensors is connected in conjunction with the variable speed valve(s) and the electronic output of the sensors is connected to an input upon a microcontroller. The Sensory inputs are utilized to, read/write data, to control the actuation speed and/or position of a variable speed valve autonomously. The UI inputs range from: voice-command, switches, motion sensors, and/or touchscreen. The UI inputs is a means to send signals to the microcontroller, in-which send a signal to a driver, moreover send a signal to control, one or more motors and/or solenoids. Furthermore, will maneuver a plurality of gears and/or driveshafts, at various speeds, to actuate the valve to an accurate and precise position.

A surge control system includes a rotor system with at least one compressor section and at least one turbine section operably coupled to a shaft. The surge control system also includes sensors configured to collect sensor data from the rotor system, an electric motor operably coupled to the rotor system, and a controller. The controller is operable to detect surge event from the sensor data, determine an amount of power to apply to the rotor system, and increase the amount of power provided to the rotor system to recover from the surge event.

A system for inflating an inflatable device includes a ducted fan aspirator coupled to the inflatable device and having a fan and a fan motor configured to drive the fan to direct first air into the inflatable device. The system further includes a compressor aspirator coupled to the inflatable device and having a compressor and a compressor motor configured to drive the compressor to direct second air into the inflatable device.

Method for controlling a plural stage compressor comprising at least a first stage (10), a second stage (20) and a first inter-stage line (12) between the first stage (10) and the second stage (20), comprising the steps of: a—measuring the temperature at the inlet of the compressor, b—measuring the ratio between the outlet pressure (Pout) and the inlet pressure (Pin) of the first stage (10) of the compressor, c—calculating a coefficient (ψ) based at least on the value of the inlet temperature (Tin) and on the measured pressure ratio (Pout/Pin), d—if the calculated coefficient (ψ) is in a predetermined range, acting on a control valve (70; 76; 92) mounted in a line (4; 8) supplying the inlet of the first stage (10) of the compressor or in a gas recycle line (74) which opens into the first inter-stage line (12).

A drag pump for pumping gas and a set of vacuum pumps including the drag pump are disclosed. The drag pump comprises: a rotor configured to rotate within a stator component and to drive a gas to be pumped from a gas inlet to a gas outlet; magnetic bearings for rotatably mounting the rotor within the pump; wherein at least a portion of the rotor and stator component configured to contact the gas to be pumped are configured for operation at temperatures above 130° C.

Provided is a compressor system including a first compressor having: an inlet at which a first inlet guide vane is provided; and an outlet pressure sensor unit configured to measure a pressure at an outlet of the first compressor; a second compressor including an inlet at which a second inlet guide vane is provided; a first control unit configured to adjust a degree of opening of the first inlet guide vane based on the pressure measured by the outlet pressure sensor unit, configured to set the outlet pressure of the first compressor as a set pressure, and configured to generate a first signal including information about the degree of opening of the first inlet guide vane; and a second control unit configured to receive the first signal, and configured to adjust a degree of opening of the second inlet guide vane to control an amount of fluid flowing into the second compressor.

Method for controlling a plural stage compressor comprising at least a first stage (10), a second stage (20) and a first inter-stage line (12) between the first stage (10) and the second stage (20), comprising the steps of: a—measuring the temperature at the inlet of the compressor, b—measuring the ratio between the outlet pressure (Pout) and the inlet pressure (Pin) of the first stage (10) of the compressor, c—calculating a coefficient (ψ) based at least on the value of the inlet temperature (Tin) and on the measured pressure ratio (Pout/Pin), d—if the calculated coefficient (ψ)is in a predetermined range, acting on a control valve (70; 76; 92) mounted in a line (4; 8) supplying the inlet of the first stage (10) of the compressor or in a gas recycle line (74) which opens into the first inter-stage line (12).

The present invention provides a control device for detecting an abnormal operation state of a compressor in a parallel refrigerator. The control device is a control device for a refrigerator that includes a plurality of compressors connected in parallel, and detects occurrence of surging and occurrence of droplet suction on the basis of a deviation between values of currents flowing through electric motors that is configured to drive each of the plurality of compressors, and an operation point indicated by the air volume and the compression ratio of the plurality of compressors.

A system and method for controlling a system that includes fixed speed and variable speed compressors are described. The method generally allows the system, for example, a heating, ventilating, and air condition (HVAC) system that includes fixed speed and variable speed compressors, to maximize unit modulating capability. The method allows the use of a variable speed compressor that is relatively smaller, which can lead to cost savings, easier installation, manufacturing, etc.