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High-volume Rotors Solve Big Problems

A modern "Big Gun" (a Nelson Irrigation trademark) looks like automated artillery from a Star Wars film. A 100 Series Big Gun has a flow capacity of 50-300 gallons per minute and is often used for dust suppression as well as for crop and sports field irrigation

Athletic field designers often choose to keep sprinklers off playing fields to avoid contact with players and potential injuries. The so-called Big Gun-type (the name is a Nelson Irrigation trademark) is an alternative to an in-ground rotor system that water fields from positions on the sides.

Another approach is Underhill International's Mirage design, which fully retracts rotors underground and covers them with turf or artificial turf caps that completely remove them from play.

All these high-volume rotors are big, high-pressure nozzles that can shoot water long distances, sometimes more than 300 feet. Matched with a traveler system, a single gun can even irrigate a soccer or football field with a single pass from one end of the field to another.

Some baseball diamonds or football fields use guns with a quick-coupler system. With quick-couplers a crew can move the gun where it is needed.

Surface-mounted rotors don’t have the installation and maintenance costs associated with an in-ground sprinkler system.

Of course, successful operation of a gun/quick coupler system depends upon careful installation. The valve must be adequately supported to counteract the thrust of the gun and must be mounted in a vertical position. Nelson Irrigation recommends using a two-inch swing joint riser.

With this method, quick coupling valves are concealed in underground valve boxes off the playing field.

Mirage Photo: Underhill International


Underhill's M-160 rotor has a throw radius of over 160 ft. The powerful sprinklers are often installed outside the playing area of football and soccer fields. Precision rotation speed adjustment and the available artificial turf cover make them suitable for synthetic sports fields. The sprinklers cover a lot of ground and pull a disappearing act when not in use. A large 4-inch deep and 9-inch diameter natural grass sod cup cover gives them virtual invisibility in the field during practice and game time.

Tracker Photo: Underhill International


The Tracker(TM) T-400 is equipped to supplement seasonal watering needs of 1/4 acre to 2 acre areas. It is also ideal for irrigating athletic fields, cemeteries, or other large campuses where an underground system is impractical. Built in Germany, the unit can irrigate an entire football field in just two passes.

Powered by water, it pulls itself along a nylon cable and automatically shuts down when it reaches the end. Connect Tracker(TM) to a 1-inch heavy-duty hose, unroll the cable and anchor it to a stake at the opposite end of the field. Then set the speed control (which controls the application rate of the water) and turn on the water.

A simple twist can attach a high-volume rotor to a valve. Disconnection and moving the gun to the next valve location is simply a matter of moving to the next attachment point. The system can also be equipped for semi-automatic operation, requiring a minimum of time and labor.

While they owe their invention to irrigation, Big Guns are also used for a variety of other applications. Set to spray with a higher trajectory, they are used to control dust and keep cattle cool in feed lots. They are also used to evenly spread wastewater for evaporation and in certain mining applications.

Golf courses and other sites that rely on sources of untreated water enjoy the guns for their consistent operation without clogging.


Rain Bird(R) 115-E Rotor

Rain Bird(R) 115-E Rotor

Distributing water up to 115 feet, the 115-E Rotor is designed for applications such as soccer, baseball and other sports fields. This valve-in-head rotor requires fewer heads and less trenching, saving users time and money. Its large distribution range also means the 115-E can be placed outside the playing field to minimize risk of player contact and injury. This model features nozzle technology that distributes water efficiently and uniformly over the entire radius range.

Layout of High-volume Rotors

With greater flows, come greater friction losses and those considering retrofit applications with high-volume irrigation products should be particularly wary of this. Using a high quality swing joint to connect high capacity rotors to the lateral will help keep losses to a minimum. Careful investigation of the existing conditions will ensure that the hydraulic capacities of the system and its components are not exceeded and enough pressure remains at the head for proper operation.

Layout of High-volume Rotors

The adjustable stator in some manufacturer's rotor products enable the high capacity rotors to operate at higher rotation speeds for syringing applications.

While this feature adds to the rotor's flexibility, proper adjustment is important, and changes with varying pressure and nozzle combinations.

In applications where distance of throw is critical, the slowest rotation speed should be selected to ensure maximum distance is achieved. As with any rotor, wind should also be taken into consideration when choosing the appropriate spacing and should be reduced appropriately to compensate.

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October 15, 2019, 5:00 am PDT

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