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 portable fluid pump comprises a tank, a positive displacement pump comprising a fluid inlet and outlet, and an electric motor that drives the positive displacement pump, wherein the electric motor is a brushless variable speed electric motor operating at 110 volts or less. A conduit diverts fluid pumped by the positive displacement pump back into the tank and an actuated valve assembly controls fluid flow through the conduit and, therefore, a pressure of fluid flow through the fluid outlet. A pair of sensors measure, respectively, a pressure and a flow rate of fluid flow through the fluid outlet. A system controller receives a target fluid pressure and fluid flow rate and adjusts a throttle position of the actuated valve assembly and a speed of the electric motor such that pressure and flow rate readings from the sensors substantially match, respectively, the target fluid pressure and fluid flow rate.

What is provided is a fuel supply system that includes a fuel gear pump that is driven by an electric motor and sends fuel in a fuel tank to a fuel nozzle that supplies fuel to the combustor, a controller that controls a rotational speed of the electric motor, and the flow rate measurer that measures the flow rate of fuel discharged from the fuel gear pump. When the difference between the fuel flow rate actually discharged from the electric motor and a target value of the flow rate is equal to or greater than a first threshold value with respect to the target value, the controller adjusts the rotational speed of the electric motor so that the measured value of the flow rate of the fuel discharged from the fuel gear pump approaches the target value.

A method for controlling a compressor towards an unloaded state, in which the compressor includes a compressor element (2) with an inlet (5), in which in the unloaded state, a residual flow (QD) is suctioned via the inlet (5) towards and into the compressor element (2), and in which for a transition from a loaded state of the compressor to the unloaded state, the inlet (5) of the compressor element (2) is partially closed in successive discrete transitional steps.

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.

Oil-injected multistage compressor device including a low-pressure compressor element (2) with a gas inlet (4a) for gas to be compressed and a gas outlet (5a) for low-pressure compressed gas and a high-pressure stage compressor element (3) with a gas inlet (4b) for low-pressure compressed gas and a gas outlet (5b) for high-pressure compressed gas. The gas outlet (5a) of element (2) is connected to inlet (4b) of element (3) via a conduit (6). The conduit (6) has a regulatable intercooler (9) configured to regulate the temperature at the gas inlet (4b) of the high-pressure stage compressor element (3) so that it is above the dew point. The intercooler (9) includes a regulatable air cooler and/or a regulatable water cooler, and is configured to adjust the temperature of the air or water by using a bypass conduit (16) and/or by screening off part of the intercooler (9).

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 of manufacturing a suction pipe for a multi-compressor device having a plurality of inlets, the suction pipe comprising a primary portion and a plurality of secondary portions arranged to receive fluid from the primary portion for supplying fluid in parallel to the inlets of a multi-compressor device. The method includes designing the suction pipe by: selecting a first dimension for the primary portion of the suction pipe, calculating a first fluid velocity for fluid in the primary portion based on the first dimension, and comparing the first fluid velocity to a first predetermined threshold; selecting a second dimension for the secondary portions, calculating a second fluid velocity for fluid in the secondary portions based on the second dimension, and comparing the second fluid velocity to a second predetermined threshold; and calculating a ratio of the first fluid velocity to the second fluid velocity.

A braking system for a hose or cable reel including a housing configured to fit inside a drum of the reel and to rotate with the drum during use, and a gerotor including inner and outer gears disposed inside the housing, wherein the inner gear is attachable to a shaft of the reel and the outer gear is configured to rotate relative to the inner gear with the housing during use thereby causing hydraulic fluid to be pumped through the gerotor and impede rotation of the drum.