A hydraulic apparatus has a plurality of pump modules each of which is formed by a plurality of working chambers having a common high pressure manifold. A connecting circuit switchably connects pump modules to first and second hydraulic circuit portions to allocate capacity as first and second demands for hydraulic fluid vary. In an apparatus which may have two or more connecting circuit outputs, valves may be controlled or working chamber pumping cycles made inactive to facilitate the reallocation of a pump module from one output to another, and a control strategy addresses pump module allocation when the demands for hydraulic fluid exceed available capacity.

A method for evacuating a process space by initially evacuating the process space to a pressure limit value using two compressors operated in parallel, and on reaching or undershooting the pressure limit value, the process space is subsequently evacuated using the two compressors operated in series.

A method for evacuating a process space by initially evacuating the process space to a pressure limit value using two compressors operated in parallel, and on reaching or undershooting the pressure limit value, the process space is subsequently evacuated using the two compressors operated in series.

A hydraulic apparatus including an electronically commutated machine having a plurality of working chambers which are controlled on each cycle of working chamber volume to carry out active or inactive cycles of working chamber volume allows only a plurality of defined fractions of cycles to be active cycles to avoid generating frequencies of active cycles which cause low frequency resonances. The demand signal may be quantised into fractions m/n where n is an integer below a threshold selected to avoid repeating patterns of active cycles of more than a cut-off length.

An economizer control system includes a compressor including a compression area, a piston chamber, and an economizer inlet configured to receive economizer vapor into the compression area via a flow path that extends between the economizer inlet and the compression area. At least a portion of the flow path traverses the piston chamber. The economizer control system also includes a piston disposed within the piston chamber and configured to contact the economizer vapor. The piston is moveable between an open position that opens the flow path and a closed position that closes the flow path. Additionally, the economizer control system includes a biasing system configured to apply force to the piston to bias the piston toward the closed position.

The present invention relates to a method of loading a fluid into a fluidic element, wherein the method is performed in a fluidic system comprising the fluidic element, wherein the method comprises determining a volume that has flown into the fluidic element since a start time t.sub.start, and at a switching time t.sub.switch, switching the fluidic system to an operating state to stop flow into the fluidic element. The present invention also relates to a fluidic system configured for performing the method, and to a corresponding computer program product.

The present invention relates to a method of loading a fluid into a fluidic element, wherein the method is performed in a fluidic system comprising the fluidic element, wherein the method comprises determining a volume that has flown into the fluidic element since a start time t.sub.start, and at a switching time t.sub.switch, switching the fluidic system to an operating state to stop flow into the fluidic element. The present invention also relates to a fluidic system configured for performing the method, and to a corresponding computer program product.

A rinsing system includes: a pump control module configured to, when a hydraulic line is connected to a port that is fluidly connected to a hydraulic line of a suspension system, selectively operate a hydraulic fluid pump of the suspension system and pump hydraulic fluid from a hydraulic fluid tank of the suspension system through the hydraulic fluid pump toward the hydraulic line; and a valve control module configured to, when the hydraulic line is connected to the port and the hydraulic fluid pump is pumping hydraulic fluid, open valves of the suspension system and fluidly connect the hydraulic fluid pump with the hydraulic line.

A reciprocating piston air compressor includes a programmable logic controller, a tank, a motor, a pump, a variable speed drive, a head unloader and a cooling system. The programmable logic controller and/or variable speed drive are utilized to monitor the operating state of the air compressor and to control various operational variables, such as motor and pump speed. The air compressor can utilize the variable speed drive to operate a three phase motor on single-phase power.

A reciprocating piston air compressor includes a programmable logic controller, a tank, a motor, a pump, a variable speed drive, a head unloader and a cooling system. The programmable logic controller and/or variable speed drive are utilized to monitor the operating state of the air compressor and to control various operational variables, such as motor and pump speed. The air compressor can utilize the variable speed drive to operate a three phase motor on single-phase power.