Traveling Gun Irrigator

Overview

A traveling gun irrigator waters a long strip of field by dragging a single large sprinkler across it at a slow, steady pace. The machine parks at one edge of the field as a trailer carrying a big hose reel. The operator unwinds the polyethylene drag hose, tows the gun cart to the far end, and starts the water. Pressure in the supply line both feeds the gun and powers a small turbine that winds the reel back in, so the gun is pulled toward the trailer at a controlled rate while it throws a wide jet over the crop. One run waters a lane as wide as the gun reaches and as long as the hose, then the operator moves the unit to the next lane.

The appeal is that no engine, no buried pipe, and no field labor during the run are needed. The whole machine runs on the energy already in the pumped water. The main parts are the Hose Reel Assembly that stores and winds the hose, the Trailer Chassis that carries it, the Gun Cart and its Sprinkler Gun, the Drag Hose that does double duty as supply line and tow rope, the Reel Drive that turns flow into reel rotation, and the Speed Control that holds a constant speed.

The hose reel and chassis

The heart of the machine is the Hose Reel Assembly. Its welded Reel Drum turns on the Reel Axle and stores hundreds of metres of hose. A Level-Wind Guide carriage traverses across the drum face as it turns, laying each wrap of hose beside the last so the hose does not bunch on one side and jam. A Reel Brake keeps the drum from spinning free and overrunning when the operator pulls hose out by tractor.

All of this rides on the Trailer Chassis, a two-wheel Trailer Frame towed by a Drawbar on Road Wheel tires. Once parked, the operator drops the Jack Stand screws to level and anchor the unit, then swings the reel on its Slewing Turntable so the hose run lines up with the lane to be watered. The turntable matters because it lets one parked position serve several lanes that fan out at slightly different angles.

The gun and its cart

The water leaves through the Sprinkler Gun, a large rotating sprinkler mounted on the Gun Cart. The Gun Body turns slowly on a water-lubricated bearing, and a Rocker Arm arm flicks into the jet to step the gun around. A Ring Nozzle sized to the available flow sets the jet diameter, throw radius, and droplet size. The Arc Mechanism holds the gun to a part-circle arc so it waters only ahead and to the sides, never back onto ground already covered, and reverses at each end of the arc.

The cart itself has to roll across a planted field without crushing the crop. Its Cart Frame is wide and low for stability, the Cart Wheel tires are tall and narrow to pass between rows, and a Gun Riser lifts the gun clear of the canopy. Where the soil is too soft for wheels, the Skid Plate lets the frame slide instead of digging in.

Hose, drive, and how the pull works

The Drag Hose is the clever part of the machine. Its PE Hose Tube is thick-walled medium-density polyethylene, stiff enough to take the towing load yet able to coil onto the drum. One end joins the reel through Hose Coupling fittings, and the other ties to the cart through a Tow Clamp, so the same hose that carries water also pulls the gun in. As the Hose Reel Assembly winds, it reels in hose and the cart follows.

The reel turns under water power. The Reel Drive puts a small Water Turbine in the supply flow that produces torque, geared down through a Gearbox Housing with Helical Gear Pair reductions and a Drive Chain to the drum. Because the gun needs only a fraction of the energy in the flow, a Bypass Valve diverts the rest around the turbine, and adjusting it sets how fast the reel winds. The Oil Seal elements keep gear oil in and field grit out.

Speed control and supply

Travel speed decides everything about the watering, because a slower pull leaves more water on each square metre. The Speed Control uses a Speed Governor to hold a constant reel speed even as the growing coil of hose increases the effective drum diameter, and a Speed Dial lets the operator set the target depth. A Pressure Sensor watches line pressure, and when the cart reaches the reel a Shutoff Cam is tripped that closes the supply and stops the turbine so the machine does not run dry or pull the cart into the trailer.

Water enters through the Inlet Swivel. A Inlet Elbow connects the field supply hose, a Inlet Strainer keeps grit out of the turbine and nozzle, and a Swivel Joint passes water into the rotating reel without leaking, sealed by an O-Ring Set.

Use, settings, and limits

Traveling guns suit medium and large fields of forage, vegetables, sugar cane, and pasture where the cost of buried mains or a center pivot is hard to justify. A single machine covers many hectares by being moved lane to lane, and it needs only a pressurized supply, which is why it is common where a stream, pond, or existing pump main is available. The trade-offs follow from the single large gun: big droplets fall hard and can pack bare soil or damage tender seedlings, the high pressure at the gun costs pumping energy, and wind distorts the wide jet so runs are best made in calm conditions. Coverage is also less even than a pivot because the wetted strip is heaviest down the centerline. Within those limits the machine is rugged, simple, and cheap to run, since the Reel Drive takes its power from the water rather than from a separate engine.