Abstract: A fluid-pressure operated pilot valve produces a cyclic modulation of pressure in a control duct, for operating a relay valve, by introducing a predetermined delay between the displacement of a first valve element from, and its return to, a first position against a first valve seat by a fluid-pressure operated timer device, which includes flow restrictor means and a pressure accumulator, acting upon the larger area side of a differential area actuator which vents the pressure in the control duct to an exhaust duct in a second position of the first valve element; the relay valve being operable in response to the cyclic pressure changes in the control duct to admit an irrigating liquid to an irrigation spray nozzle.

Abstract: A self-cleaning flow-regulating valve for an irrigation system has a displaceable element which is adjustable axially within a valve body by rotation of an external nut to adjust the position relative to two opposing seats of a floating bush which defines the size of a flow passage for irrigating liquid.

Abstract: An improvement in pneumatic anti-skid braking systems for at least one wheel of a vehicle, of the type having a first valve system for causing a controlled reduction in braking pressure in a brake actuator upon reception of a control signal from an anti-skid control device sensitive to the dynamic state of at least one wheel of the vehicle, and a second valve system for causing a subsequent controlled rise in pressure after the signal from the anti-skid control device has been removed, the improvement being the provision of an accumulator in parallel with the first valve system and having two unidirectional valves, one at each side, which permit the accumulator to charge up to the braking pressure during normal braking, store this pressure upon anti-skid release of the braking pressure, and then deliver its charge to the circuit, causing a rapid increase of braking pressure after the anti-skid control signal is removed from the first valve system.