A compressor control system includes: a compressor; an inlet guide vane (IGV) arranged at an inlet of the compressor, and configured to adjust opening of the inlet based on a supplementary surge control signal or a performance control signal; an anti-surge valve (ASV) connected to an outlet of the compressor, and configured to prevent a surge based on a surge control signal; and a controller configured to generate the surge control signal for controlling the ASV when an operating point enters a surge control range, generate the supplementary surge control signal for controlling the IGV in an anti-surge mode when the operating point enters a supplementary surge control range set between the surge control range and a surge range, and generate the performance control signal for controlling the IGV in a performance mode until the operating point enters the surge control range.

A control method of a centrifugal compressor (C) mechanically coupled to an expansion turbine (TorC), the centrifugal compressor (C) being provided with at least a control system (20) of the absorbed power. The control method of the rotation speed of the turbine-centrifugal compressor group performs the following steps: acting on the centrifugal compressor control system (20) of the absorbed power by means of a first controller (PID-f), in order to keep constant the rotational speed of the compressor mechanically coupled to the expansion turbine;ensuring that the centrifugal compressor (C) remains in a stable operating condition by means of an admission valve (Vi) of the expansion turbine (TorC).

A system of interlocks for controlling flow of low temperature process streams in a manufacturing process through a cold box to equipment or piping not specified for such temperatures by opening and closing valves and starting and stopping pumps. At least one interlock affects streams heated in the cold box. At least one interlock affects the streams cooled in the cold box. The interlocks are activated by temperatures of process lines to prevent exposure of equipment and piping to low temperatures while preventing the shutdown of the cold box. An override controller including a predictive failure capability is also provided.

A method of preventing standing waves in an installed gas turbine having a fan, having a fan speed, and a compressor, having a compressor speed, includes correcting the fan and compressor speeds for temperature and monitoring the corrected speeds to prevent them from converging, or becoming the same value. In addition, a computer implemented monitoring and adjusting program may monitor a position of an aircraft on a ACTFS plot and make adjustments to avoid intercepting a surge line by changing the speed of the plane, one or both of the fan or compressor speeds or by changing altitude. An aircraft may form a standing wave when crossing or operating on a surge line of an ACTFS plot and this condition should be avoided which may require high data rate monitoring and control logic.

The invention discloses a centrifugal compressor. The centrifugal compressor includes multiple stages of compression units which are communicated in sequence. Each stage of compression unit includes a diffusion cavity (1) and a diffusion adjustment device, wherein the diffusion adjustment device includes a movable member (21) configured to change a radial flow area of the diffusion cavity (1) provided in correspondence thereto, the movable member (21) being movably provided in an axial direction of the centrifugal compressor. The invention also discloses a centrifugal unit having the centrifugal compressor. The movable member of each stage of compression unit of the centrifugal compressor changes the radial flow area of the diffusion cavity of this stage of compression unit, thereby effectively reducing the possibility of surging.

A gas turbine equipped with: a low-pressure bleed passage, a medium-pressure bleed passage, and a high-pressure bleed-passage for supplying compressed air bled from respective bleed chambers to a turbine; a low-pressure exhaust passage, a medium-pressure exhaust passage, and a high-pressure exhaust passage for exhausting the compressed air in the respective bleed passages to an exhaust chamber; a low-pressure exhaust valve, a medium-pressure exhaust valve, and a high-pressure exhaust valve provided respectively in the exhaust passages; a low-pressure ejector and a medium-pressure ejector provided in the respective exhaust passages; a driving air supply passage for supplying the compressed air to the ejectors; and a control device that opens the exhaust valves and supplies compressed air from the driving air supply passage to the ejectors when the operating state of a gas turbine is in a region in which rotation stall is generated.

An apparatus for suppressing a surge of a turbo compressor is provided. The apparatus includes a compressor housing having a compressor wheel provided therein and an inlet having air flowing thereinto and protruding from a first opposite to the compressor wheel. A connection module has a first side connected to the compressor housing to communicate with the inlet and a second side that includes an inlet for supplying air. A flexible cone of an elastic material is disposed in the connection module and is formed in a conical shape having sizes of cross-sectional areas of a first side and a second side that are different from each other. A spring member is coupled to an exterior circumferential surface of the flexible cone to provide an elastic force and operated to change a size of a cross-sectional area of the first or second side of the flexible cone.

A method for controlling multi-stage centrifugal compressors is provided. The method includes, for each stage of the compressor, defining a Mach ratio and impeller diameter, calculating a minimum required motor drive frequency to operate free from surge conditions for a current head factor and flow reduction device position, and adjusting the flow reduction device position while maintaining an actual motor drive frequency at a acceptable level to achieve a leaving chilled water temperature set point. The method also includes measuring a suction pressure and a discharge pressure and calculating a saturated suction temperature and a saturated discharge temperature for each stage of the compressor. The method further includes calculating an actual minimum motor drive frequency that is the greater of a first actual minimum motor drive frequency and a second actual minimum motor drive frequency associated with a first compressor stage and a second compressor stage of the compressor, respectively.

A method of sharing load between a plurality of parallel fluid pumps in a subsea fluid pumping system (1) comprising a first fluid pumping unit (2a) comprising a first pump (3a) and a first motor (8a) which is drivingly connected to the first pump, which first pump comprises a suction conduit (4a) which is in fluid communication with a fluid inlet conduit (5), and a discharge conduit (6a) which is in fluid communication with a fluid outlet conduit (7); a second fluid pump unit (2b) comprising a second pump (3b) and a second motor (8b) which is drivingly connected to the second pump (3b), which second pump comprises a suction conduit (4b) which is in fluid communication with the fluid inlet conduit, and a discharge conduit (6b) which is in fluid communication with the fluid outlet conduit, thus rendering the second pumping unit parallel to the first pumping unit; a return conduit (9) providing a feed-back path for the fluid from the outlet conduit to the inlet conduit; and a control valve (10) controlling the flow of the fluid through the return conduit. The method comprises the steps of establishing pump limit characteristics diagrams (15a, 15b) for the first and second pumping units by mapping a minimal allowable torque of each pumping unit as a function of a differential pressure across the corresponding pump and identifying a permissible operating region (16a, 16b) of the pumping units defined by a set of minimum allowable torque values; monitoring the torque of the pumping units and the differential pressure across the pumps acquiring a monitored torque value and a monitored differential pressure value of the pumping units, and identifying the minimum allowable torque value of the pumping units corresponding to the monitored differential pressure value; and regulating the rotational speed of the pumps such that the relation between the monitored torque values is the same as the relation between the minimum allowable torque values of the pumping units.

A method for controlling a compressor that includes a compressor element, whereby during a transition from full load or partial load to zero load, a process A is followed that involves: (1) reducing the inlet pressure; and (2) reducing the speed and/or the drive torque. During a transition from zero load to part load or full load, a process B is followed that involves: (3) increasing of the speed or drive; and (4) increasing the inlet pressure.