In a method for operating a hydraulic device for providing a supply to hydraulic consumers (V) on a plastics injection moulding machine, provision is made of a pump (10) with a volumetric delivery characteristic that results in cyclic pulsations and of a servomotor (11) with multiple poles that result in cyclic pulsations. The pressure at the hydraulic consumer (V) is detected and is input as an actual value into a pressure regulator (13) that readjusts the servomotor (11), on the basis of a predefined pressure profile, to a pressure setpoint value at the hydraulic consumer (V). The cyclic pressure pulsation is minimized in that, by means of a rotational angle sensor (20), the rotational angle (φ) of the pump (10) and/or of the servomotor (11) is detected and correlated with the cyclic pulsations, and in that, from this, a corrective value or a corrective function is determined and is transmitted to the pressure regulator (13) with control subordinate to the regulation of the pressure setpoint value. Alternatively or in addition, this is achieved in the case of a hydraulic device also in that, as corrective means for the pressure regulation, said means being subordinate to the consideration of the pulsations, the number of components of the pump (10) that result in the cyclic pulsations and the number of components of the servomotor (11) that generate cyclic pulsations are equal, or one is a multiple of the other.

According to one embodiment, a system and process for the equalization of pressures of a flow stream across one or more valves is provided. A process circuit having clean non-abrasive fluid and at least one slave cylinder fbr transmitting pressure to a process flow stream is employed.

Various embodiments provide a leaching solution monitoring module comprising a first leaching solution distribution system interface, a flow meter in fluid communication with the first leaching solution distribution system interface, the flow meter in fluid communication a 3-way pressure regulator, and a second leaching solution distribution system interface in fluid communication with the 3-way pressure regulator.

An accumulator assembly for a pump system at a well site is arranged to fluidically connect to a flow line between a blender and a fracturing pump of the pump system. The accumulator assembly includes a pressurizable tank configured to contain pressurized fluid; and, a control valve fluidically connected between a discharge end of the tank and the flow line. The control valve opens and fluidically connects the tank to the flow line when a pressure on the flow line is less than a target pressure, and the control valve closes and fluidically blocks communication between the tank and the flow line when the pressure on the flow line is greater than or substantially same as the target pressure.

An apparatus and method controls an environmental control system to maintain a differential pressure between a room and one or more adjacent areas by (1) determining a differential pressure error based on the differential pressure and a differential pressure set point using a proportional-integral-derivative (PID) controller; (2) increasing an air change per hour set point whenever one or more first parameters are satisfied; (3) decreasing the air change per hour set point whenever one or more second parameters are satisfied; and (4) sending one or more control signals to the environmental control system that maintain the differential pressure between the room and the one or more adjacent areas by adjusting: (a) the leading airflow to be approximately equal to the air flow change set point multiplied by a volume of the room divided by 60, and (b) the tracking airflow to maintain a volume differential set point.

The invention relates to energy saving in vacuum systems by means of a method and a controller enabling to consider the fluctuation in system-pressure of a system by determining a maximum system-pressure S2H and a minimum system-pressure S2h for each working cycle W.sub.C based on a determined target system-pressure p.sub.n.sup.− and a pre-set system-pressure p.sub.0.sup.− for the current working cycle W.sub.Cn (n=1, 2, 3, . . . ). The method is especially adapted to fluctuations in system-pressure level of a vacuum system comprising a vacuum gripper tool.

A pressure control device maintains a pressure within a target of pressure control at a set pressure. The pressure control device includes a correction circuit that corrects a pressure signal, which represents the pressure within the target of pressure control that is detected by a pressure sensor, such that the pressure signal approaches a set pressure signal representing the set pressure; a comparison circuit that compares the corrected pressure signal with the set pressure signal; and a valve drive circuit that controls an opening and closing of a flow control valve based on a comparison result from the comparison circuit. The correction circuit is a filter circuit. The frequency characteristic of the filter circuit has a peak at a prescribed frequency, and corrects the pressure signal so as to raise a component of the prescribed frequency of the pressure signal.

A pressure control device maintains a pressure within a target of pressure control at a set pressure. The pressure control device includes a correction circuit that corrects a pressure signal, which represents the pressure within the target of pressure control that is detected by a pressure sensor, such that the pressure signal approaches a set pressure signal representing the set pressure; a comparison circuit that compares the corrected pressure signal with the set pressure signal; and a valve drive circuit that controls an opening and closing of a flow control valve based on a comparison result from the comparison circuit. The correction circuit is a filter circuit. The frequency characteristic of the filter circuit has a peak at a prescribed frequency, and corrects the pressure signal so as to raise a component of the prescribed frequency of the pressure signal.

A vacuum valve placed between a vacuum vessel and a vacuum pump to adjust a valve opening degree using an operating fluid includes a packing mounted in a recessed groove of a piston. The packing is provided with a contact portion on a radially inner side and a contact portion on a radially outer side, and a slide-contact portion contacting with an inner peripheral surface of a cylinder. A portion between the contact portion and the slide-contact portion has a thin thickness.

A hydraulic valve arrangement (1) is provided comprising comprising a supply port arrangement having a high pressure port (2) and a low pressure port (4), a working port arrangement having two working ports (6, 7), a first valve (13) arranged between said high pressure port (2) and said working port arrangement (6, 7), a second valve (14) arranged between said low pressure port (4) and said working port arrangement (6, 7), a controller (19) for controlling said first valve (13) and said second valve (14), said controller (19) having an input connection (20) for receiving a signal of an operator input device, and a regenerative flow path which can be established by means of at least one of said first valve (13) and said second valve (14). The function of such a hydraulic valve arrangement should be enhanced. To this end said controller (19) said controller interrupts said regenerative flow path when a feed pressure at said working port arrangement (6, 7) exceeds a predetermined pressure level.