A fluid-driven actuator system includes a fluid-driven actuator and at least one proportional control valve and at least one pump connected to the fluid-driven actuator to provide fluid to operate the fluid-driven actuator. The at least one pump includes at least one fluid driver having a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from the pump inlet to the pump outlet. The fluid driven actuator system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover to adjust at least one of a flow in the fluid system to a flow set point and a pressure in the fluid system to pressure set point and a concurrently establishes an opening of the at least one proportional control valve to adjust at least one of the flow to the flow set point and the pressure to the pressure set point.

A method for controlling the speed of a compressor with a controller as a function of the available gas flow comprising the following steps: setting a desired value for the inlet pressure; determining the inlet pressure; determining the speed; controlling the speed of the compressor by reducing or increasing it depending on whether the inlet pressure is less than or greater than the set desired value until the inlet pressure is equal to the set desired value; providing the characteristic data of the compressor relating to the efficiency and/or the Specific Energy Requirement (SER) as a function of the speed and the inlet pressure; adjusting the desired value of the inlet pressure on the basis of the aforementioned characteristic data and in such a way that the efficiency of the compressor is a maximum or the SER is a minimum.

A method of controlling a liquid ring pump in a pump system includes monitoring a vacuum pressure of the liquid ring pump using a pressure transmitter configured to transmit a vacuum pressure signal to a controller in operative communication with the liquid ring pump. The method also includes maintaining a predetermined vacuum pressure in the liquid ring pump under variable vacuum flow demand within the pump system in response to the vacuum pressure signal by controlling, via instructions from the controller, a parameter of the liquid ring pump based on a comparison of the vacuum pressure signal to the predetermined vacuum pressure by the controller.

A control system comprising: a suction line; an exhaust line; an operating liquid line; a liquid ring pump coupled to the suction, exhaust, and operating liquid lines; a regulating device configured to control flow of operating liquid into the liquid ring pump; a pressure sensor configured to measure a pressure of an input fluid to the liquid ring pump via the suction line; a first temperature sensor configured to measure temperature of an exhaust fluid output by the liquid ring pump via the exhaust line; a second temperature sensor configured to measure temperature of an operating liquid received by the liquid ring pump via the operating liquid line; and a controller configured to: using the sensor measurements control the one or more regulating devices.

A liquid-cooled rotary compressor includes a compressor main body having a compression chamber formed by a fixed wall and a rotating wall and compressing gas, and a liquid injection path for injecting a coolant into the compression chamber, and adjusts a discharge flow rate by changing a rotational speed of the rotating wall. The compressor includes a liquid amount adjusting unit that adjusts an amount of the coolant supplied from the liquid injection path to the compressor main body according to a change in the rotational speed of the rotating wall, and a compressed gas supply path that supplies compressed gas to a downstream side of the liquid amount adjusting unit in the liquid injection path. The compressed gas is supplied from the compressed gas supply path to the liquid injection path according to the amount of the coolant supplied to the compressor main body.

A scroll compressor with a first valve having a first surface to open/close between a first path and a second path; a back pressure chamber assembly or non-orbiting scroll having a third path through which a first pressure refrigerant flows, a fourth path through which refrigerant of a second pressure lower than the first pressure flows, and one end in communication with the third and fourth paths and the other end having a fifth path in communication with a second surface of the first valve; and a second valve provided where the third, fourth, and fifth paths to meet and moveable between first and second positions, wherein at the first position the third and fifth paths communicate to supply the first pressure refrigerant toward the second surface, and at the second position the fourth and fifth paths communicate to supply the second pressure refrigerant toward the second surface.

A thermo actuator includes an actuator body and a large-diameter portion (54) that projects from the actuator body outward in the radial direction. The outer diameter of a return spring is smaller than the inner diameter of a case. The outer diameter of the actuator body and the outer diameter of a valve body are smaller than the inner diameter of the return spring. The outer diameter of the large-diameter portion is smaller than the inner diameter of the case and is larger than the average diameter of the return spring. One end of the return spring is in contact with the large-diameter portion.

A pump assembly is provided and includes a housing having first, second and third pairs of fluid openings and first, second and third rotary pumps, which are co-rotatable about a common longitudinal axis defined through the housing to drive fluid flow relative to the first, second and third pairs of fluid openings, respectively. The first rotary pump includes an input member receptive of rotational drive energy for the first, second and third rotary pumps.

A variable displacement transmission pump having a controller for adjusting the displaced volume, which controller actuates corresponding adjuster actuators of the adjustable pump via a control valve, so that the pump can be adjusted from minimum to maximum displaced volume in order to achieve a constant pump outlet pressure for supplying a hydraulically operated transmission, wherein for different operating points of both the adjustable pump and the transmission, the input variables of the controller are adjusted in such a way that, independently of the individual operating points, the overall damping of the control system comprising pump and transmissionthat is, using corresponding influence variables from these systemscan be maintained substantially constant under variable operating conditions by means of adjustable controller amplification.

An embodiment of a system with a minute measure of pulsatility in a flow of a fluid is described that comprises a first pump configured to flow the fluid to a junction at a first flow rate that comprises a measure of pulsatility; and a second pump configured to flow a portion of the fluid from the junction at a second flow rate that is less than the first flow rate to produce a flow of the fluid at a third flow rate from the junction with a minute measure of pulsatility.