An electropneumatic switch valve includes a pneumatic circuit to a pressurized fluid source, an electromagnetic circuit coupled to the pneumatic circuit, and a control module connected to the electromagnetic circuit. The control module provides a first control signal inducing a first state of the pneumatic circuit, a second control signal inducing a second state of the pneumatic circuit, a third control signal inducing a third state of the pneumatic circuit, and a fourth control signal inducing a fourth state of the pneumatic circuit.

A transducer with a lower housing assembly and an upper housing assembly is for connection to a fluid pressure source having a mechanism for setting a pneumatic output via an electrical input signal. The lower housing assembly comprises lower housing configured to receive a supply nozzle, which fluidly communicates with a supply port and intermittently fluidly communicates with an output port of the lower housing through an internal fluid passageway. The lower housing further comprises an exhaust nozzle fluidly communicating with an exhaust port and intermittently fluidly communicates with the output port of the lower housing through the internal fluid passageway. The upper housing assembly comprises an upper housing configured to receive a coil and an armature such that the upper housing, coil and armature define a latching electromagnetic circuit that provides alternating contact of the armature with the supply nozzle and the exhaust nozzle of the lower housing assembly.

A system including a rotary isobaric pressure exchanger (IPX) configured to exchange pressures between a first fluid and a second fluid. The rotary IPX includes a rotor and a shaft coupled the rotor. Additionally, the system includes a hydraulic drive system including a hydraulic drive device coupled to the rotor via the shaft. The hydraulic drive device is configured to receive a hydraulic fluid and to convert hydraulic energy of the hydraulic fluid into mechanical energy to rotate the rotor at a rotational speed that is based on a flow rate of the hydraulic fluid entering the hydraulic drive device.

A system including a rotary isobaric pressure exchanger (IPX) configured to exchange pressures between a first fluid and a second fluid. The rotary IPX includes a rotor and a shaft coupled the rotor. Additionally, the system includes a hydraulic drive system including a hydraulic drive device coupled to the rotor via the shaft. The hydraulic drive device is configured to receive a hydraulic fluid and to convert hydraulic energy of the hydraulic fluid into mechanical energy to rotate the rotor at a rotational speed that is based on a flow rate of the hydraulic fluid entering the hydraulic drive device.

A pump having a fluid driver disposed within the interior volume of the pump and to a method of delivering fluid from an inlet of the pump to an outlet of the pump using the fluid driver. The fluid driver includes a variable-speed and/or a variable torque prime mover and a fluid displacement assembly. The pump can be used in a fluid pumping system to provide fluid to an actuator that is operated by the fluid. At least one of a speed and a torque of the pump is controlled so as to adjust at least one of a flow and a pressure in the fluid pumping system to a desired set point, without the aid of another flow control device.

A method for preventing control-induced oscillations in a valve with a pneumatic actuator and position control with an integrating component, including the following steps: Checking whether oscillations of the valve member occur by counting the zero crossings or extreme values of the control difference. If oscillations were detected, it is checked whether they result from oscillations of the set point. If not, the dead zone is increased and/or the gain parameter is decreased. If no oscillations were detected, it is checked whether wear in the drive has exceeded a predetermined measure. If so, the dead zone is decreased and/or the gain parameter is increased. In this way, oscillations caused by the I-component of the control can be detected and stopped. Further changes to the parameters are only made when friction is expected to have decreased due to wear.

A fluid control system is provided for controlling flow of a process fluid through a pipeline. The fluid control system can include a valve, one or more instruments in fluidic communication with the valve, and a pressurized chamber. In one example, the pressurized chamber contains the one or more instruments. In one example, the pressurized chamber has a dynamically variable pressure, which corresponds to a pressure in a downstream portion of the pipeline, such as a natural gas pipeline. In another example, the pressurized chamber captures instrument gas bled/leaked from the instruments and reinjects the instrument gas into the downstream portion of the pipeline.

The present invention relates to a hydraulic attachment comprising a hydraulic circuit, the attachment being a construction or demolition tool, in particular a hydraulic breaker, demolition shears, scrap shears, a pulverizer, a gripper, a crusher bucket or a compactor, which can be mechanically connected to a support device and hydraulically connected to the hydraulic system of the support device. In order to enable the hydraulic circuit to be opened quickly and safely within an attachment and, in particular, to make it possible to display the presence of a particular pressure level within a hydraulic attachment and to determine whether a dangerous residual pressure is present in the system, a hydraulic attachment is proposed that has a residual pressure display (40) which is connected to the hydraulic circuit of the attachment in a detachable or non-detachable manner.

The present invention relates to a hydraulic attachment comprising a hydraulic circuit, the attachment being a construction or demolition tool, in particular a hydraulic breaker, demolition shears, scrap shears, a pulverizer, a gripper, a crusher bucket or a compactor, which can be mechanically connected to a support device and hydraulically connected to the hydraulic system of the support device. In order to enable the hydraulic circuit to be opened quickly and safely within an attachment and, in particular, to make it possible to display the presence of a particular pressure level within a hydraulic attachment and to determine whether a dangerous residual pressure is present in the system, a hydraulic attachment is proposed that has a residual pressure display (40) which is connected to the hydraulic circuit of the attachment in a detachable or non-detachable manner.

A positioner is provided with a control calculating portion 1 including first and second calculating portions. The first calculating portion, a valve opening detecting portion, and a first pressure sensor are contained in a first case. The second calculating portion, an electropneumatic converting portion, a pneumatic circuit portion, and a second pressure sensor are contained in a second case. The first case is assembled together with the valve, and the second case is located in a position away from the valve. Output signals from the first calculating portion, which are a control signal MV (a PWM signal) and a detected pressure signal S1 (wherein a detected pressure signal S1 has been converted into a digital signal, are sent to the second calculating portion through cables 16.