Abstract: Method and apparatus for controlling an irrigation system within prescribed limits of pump capacity and flow capacity through water line branches and defined local zones. Watering schedules may be all simultaneously activated and will make multiple requests for watering time, for posting in a flow management roster. The requests in the roster are processed and satisfied only if overall pump capacity permits and if local flow zone capacities, and the capacities of water lines feeding the flow zones, are not exceeded. Pump capacity is expanded incrementally as more requests are processed, but only in accordance with predefined limits on the conditions that have to be met before moving to an expanded capacity. This flow management technique is best employed with a cycle-and-soak feature to avoid runoff problems at selected sites, and using an evapotranspiration approach to vary the watering times in accordance with changing weather conditions.

Abstract: A rain detector is provided for preventing operation of an irrigation system upon detection of an adjustably selected amount of rainfall. The rain detector is designed for use with an automatic irrigation control system of the type including a clock controller to electrically operate one or more normally closed valves for programmed supply of irrigation water to sprinklers individually or in selected groups. The rain detector comprises a switching circuit connected electrically in series with the sprinkler valves, with the switching circuit including spaced sensors extending for an adjustable depth into a collection tray exposed to rainfall. The switching circuit is normally closed in the absence of rainfall to permit normal programmed operation of the sprinkler valves.

Abstract: A low-cost control system for irrigation valves and the like, including a station advance control unit and a plurality of valve control units connected in a series string by a pair of power supply lines from the station advance control unit, each of the valve control units being associated with a single valve or a single group of valves. When power is first applied to a valve control unit, it actuates the valve or valves with which it is associated, and blocks the flow of power to succeeding control units in the series string. When a station advance signal is transmitted along a third line connected to all of the valve control units, the most remote control unit to which power is connected responds by deactuating its valve or valves, and switching power through to the next unit in turn.

Abstract: For use with a remotely actuated fluid supply valve, an internally balanced pressure regulating module is provided for regulating the pressure downstream of the valve by modulating the rate at which fluid is bled from a closure chamber of the valve in response to downstream pressure. The module includes a flow restricting member arranged at the open end of a cylinder and having a first surface facing the open end of the cylinder and a second surface facing outwardly of the cylinder and exposed to downstream pressure. The flow restricting member is secured to a piston in the cylinder which is resiliently biased toward the open end of the cylinder, and the downstream pressure acting on the second surface urges the first surface against the force of the biasing means, into a flow restricting relationship with the open end of the cylinder.