A twin chamber air dryer for a pneumatic system of a commercial vehicle comprises: a supply inlet port, a supply outlet, a compressor control outlet, and an exhaust outlet; a first desiccant cartridge and a second desiccant cartridge, to be operated alternately; a toggling valve assembly for switching between the first and second desiccant cartridges; a pneumatically controlled purge valve switchable between a blocking basic position and an activated position; and a solenoid valve assembly. The solenoid valve assembly comprises a directional control solenoid valve for receiving an electrical direction control signal and controlling the toggling valve assembly, a regeneration solenoid valve for receiving an electrical regeneration control signal and providing pressurized air in regeneration phases of the desiccant cartridge, and a governor solenoid valve for receiving an electrical governor control signal and controlling the purge valve and a compressor mode.

A process valve apparatus (10), including: a process fitting (1) with a valve member (2), a pneumatic valve drive (3) for actuating the valve member (2), and a control device (4) with a pneumatic valve device (5) for pneumatically actuating the valve drive (3), wherein the control device (4) is configured to carry out a partial stroke test and, within the partial stroke test: to actuate the valve drive (3) pneumatically by means of the valve device (5), so that the valve drive (3) sets the valve member (2) in a test movement sequence in which the valve member (2) performs a first test movement from a first position (x1) to a second position (x2) and a second test movement from the second position (x2) back to the first position (x1), to detect pressure information related to the pneumatic actuation of the valve drive (3) and, taking into account the pressure information, to determine status information indicating the functioning and/or the wear of the process valve apparatus (10).

There is provided an air pressure system for controlling an air compressor in real time in accordance with the actual usage of compressed air by a plurality of terminals. Furthermore, in case pressure losses change abruptly, unwanted electric power is prevented from being consumed by a stable operation free of response delays on the basis of a predicted model that assesses time lags of volume responses. There is provided an air pressure system for supplying compressed air discharged from an air compressor through an air tank and a piping system to a plurality of terminals that consume the compressed air, including a compressor pressure sensor for measuring the pressure of compressed air discharged from the air compressor, a plurality of terminal pressure sensors for measuring the pressures of compressed air supplied respectively to the terminals, a flow rate difference calculating device for calculating deviation information on the basis of a capacity of the air tank, information on the piping system, the pressure of compressed air discharged from the air compressor, and the pressures of compressed air supplied respectively to the terminals, and a control device for controlling operation of the air compressor on the basis of the deviation information.

This invention relates to an automatic vehicle wash apparatus employing one or more rotary cloth or foam rubber brushes, and more particularly to the way how the rotary brush to vehicle surface contact is managed using one or more encoders connected to the rotating shaft of each brush and one or more programmable logic controllers (PLC). The encoders, recording the revolutions per minute (RPM) of each brush shaft, provide input to the programmable logic controller. If the RPM value is at or above the high RPM limit, the pivoted boom will move the brush toward the vehicle to achieve a desired brush-to-washable surface contact. If, on the other hand, the RPM value is at or below the low RPM limit, the pivoted boom will move the brush away from the vehicle to achieve a desired brush-to-washable surface contact.

A method for operating a fluid system including the steps: receiving or determining a set value for a stroke of the working valve, determining an actual value for the stroke of the working valve using a sensor signal of a position sensor, determining a deviation value of a working valve in dependence on sensor signals of a supply pressure sensor and a working pressure sensor and a position sensor and a sensor system, and performing a processing of the set value for the stroke of the working valve, the actual value for the stroke of the working valve and the deviation value to a control signal for driving the working valve.

An aircraft pneumatic system including a pneumatic actuator arranged to operate at a pressure value at least equal to a pressure threshold, a line fluidly connected between a pneumatic source and the pneumatic actuator, and a venturi disposed upstream of the line and downstream of the pneumatic source. The venturi is configured to receive a source flow from the source at a mass flow rate, the mass flow rate being between a lower, nominal flow rate value and a higher, graded flow rate value. The venturi is sized such that when the mass flow rate is at the nominal flow rate value, a line pressure inside the line corresponds to a source pressure upstream of the venturi, and when the mass flow rate to the venturi is at the graded flow rate value, the line pressure is less than the source pressure.

A method is for controlling an actuation force exerted by an actuating device having a first working chamber and a second working chamber supplied with pressurized air from a source of pressurized air by a first pressure regulator and a second pressure regulator. The method includes calculating, by an optimization algorithm based on a dynamic model of the actuating device and of the first and second pressure regulators, desired values for control signals for the first and second pressure regulators to generate an actuation force equal to a desired value for the actuation force. An estimated value for the actuation force, estimated values for pressures inside the first and second working chambers and for first derivatives of the pressures, are determined by a state observer based on a measured value for the actuation force and on measured values for the pressures in the first and second working chambers.

A method and system for operating pneumatic suspension system including a plurality of air springs changing a ride height of the motor vehicle by the supply and extraction of compressed air, at least two first axle air springs, and two second axle air springs, an air spring valve, a first and further changeover valve are arranged in a compressed air path, an additional accumulator valve, the second compressed air path is connected to the first compressed air path via a third compressed air path in which a connecting valve is provided, for simultaneous adjustment of the ride height of the vehicle on both axles, the air spring valves, and the first and the further changeover valves and the additional accumulator valve are opened at the same time while the connecting valve remains closed.

A bypass for an air dryer having an inlet, a prefiltration stage having a drain valve to purge contaminants, a pair of inlet valves in communication with the prefiltration stage to control the flow of compressed air through the desiccant towers, and an outlet coupled to the pair of desiccant towers. The bypass may be a bypass valve that is normally open to the outlet when the air dryer is unpowered and pilotable to be a closed to allow air to flow to the prefiltration stage when the air dryer is powered. The bypass may be a three-way valve that is normally coupled to the outlet and that may be piloted to connect to the prefiltration stage when the dryer is powered. The bypass may also be a check valve that opens in response to pressure in the inlet to allow compressed air to flow directly to the outlet.

A main flow path that introduces high-pressure air to an air cylinder, or discharges exhaust air therefrom, includes a sub flow path provided alongside the main flow path; an exhaust flow rate adjustment unit that suppresses the operation speed of the air cylinder by adjusting the flow rate of the exhaust air flowing through the sub flow path; and a switching valve that is connected between the air cylinder, the main flow path and the sub flow path, and that connects the main flow path and the sub flow path to the air cylinder in a switching manner. The switching valve is constituted by a spool valve.