Irrigation sprinklers are known for watering circular patterns or arc segments of a circular pattern. Typical irrigation sprinklers discharge a single rotary water stream that is rotated in a circle around a vertical rotational axis. This water stream is thrown by a sprinkler nozzle mounted in the peripheral sidewall of the nozzle head at an upward angle relative to the horizontal to direct the water a radial distance from the nozzle.
Irrigation systems generally comprise multiple sprinklers within multiple watering zones. Each sprinkler is recessed within the ground and is fed water through underground pipes. An irrigation controller activates a zone by opening a valve that controls the flow of water through the pipes of the zone. The irrigation controller activates the zones sequentially for a predetermined period of time based on zone program instructions.
Irrigation sprinklers currently have several drawbacks. The most significant is that they spray water in circles that are overlapped between sprinklers in order to conform to complex landscape shapes. This causes excess water to be deposited in the areas where these sprinklers overlap. In many systems 50% excess water is used.
Another drawback to conventional irrigation sprinklers is that they use only a few nozzles or nozzle openings. One drawback is that some nozzles spray a fine mist close to the sprinkler which results in water evaporation due to the small droplet size. Another drawback is that some of the nozzles must water a large annular ring around the sprinkler which results in watering that is not uniform across the annular ring (i.e., in a radial direction from the nozzle). As a result, these conventional sprinklers waste water and are inflexible to landscape variations.
Irrigation systems have been disclosed that comprise, for example, a computer server with one or more wireless networks, one or more computerized sprinklers with a digitally controlled valve connected by wire to the server, one or more controllers with Wi-Fi plus another wireless network and one or more flow sensors connected by wire to the controller. Exemplary irrigation systems are disclosed in International Patent Application Serial No. PCT/US2011/044337, filed Jul. 18, 2011, and U.S. patent application Ser. No. 13/744,588, filed Jan. 18, 2013. The above referenced patent applications are incorporated herein by reference in their entirety. In these irrigation systems, each sprinkler provides a uniform incremental amount of precipitation to the soil for each revolution and can also adjust the incremental amount for a given arc portion of a revolution. In one embodiment the server and controller are combined and in another embodiment they are separate thereby creating more flexibility.
The systems must be properly calibrated to provide the desired watering pattern including the throw distance the watering stream travels from the sprinkler head over various arc portions of a revolution. Furthermore, it has been determined that a consistent pressure and flow are desirable to maintain efficiency where efficiency is defined by the system using the desired amount of water. Too much pressure causes too much flow resulting in over-watering and a throw distance that is too long, and too little pressure causes too little flow resulting in under-watering and a throw distance that is too short.
An installation contractor may use a pressure gauge to measure static pressure, but that does not account for working pressure loss under flow conditions in pipes and fittings in the field. The contractor can also turn on the sprinkler and measure the distance of the streams which are reflective of the flow conditions under working pressure, but this has proven to be complicated and slows down the installation. There is a need for automatically finding the effective pressure for a particular irrigation sprinkler and setting the sprinkler distance at a particular installation site.