Sprinkling Machines and Installations

devices that are used for sprinkling agricultural crops. They are mounted on a tractor or move independently through the plot being irrigated; sprinkling installations are portable.

The main operating units of sprinkling machines and installations are short-range spray nozzles (watering range of 5-8 m) and medium-range (15-35 m) and long-range (40-80 m) sprinkling devices. Nozzles do not have rotating parts. In deflector nozzles, which are the most common, the water is separated into drops upon striking a deflector (cone); in centrifugal nozzles (with spiral ducts) the water is separated by centrifugal force. At low pressure, deflector and centrifugal nozzles provide a uniform spray with a drop diameter of 1-1.5 mm and an intensity of about 1 mm/min. Sprinkling devices consist of one or several shafts with nozzle tips that rotate about their vertical axis during watering. The stream of water, which is emitted from the tip at a speed of 20-30 m/sec and higher, is broken up into drops by the air. The diameter of the tips and the speed of rotation of the device are selected in such a way that the area being irrigated is covered by a uniform quantity of water and the diameter of the drops does not exceed 1.5-2.5 mm. The size of the drops and the intensity of the spray may be controlled by attaching tips of different diameters (for long-range apparatus, 15-40 mm and more; for medium-range apparatus, 3-15 mm) and by varying the water pressure. Long-range devices have high output, but they produce a heavier spray than short-range nozzles; this leads to rapid formation of puddles and runoff. Medium-range devices are characterized by low spray intensity (averaging 0.1-0.2 mm/min; it may be lowered to 0.05-0.06 mm/min) and small drop diameter, as a result of which they may be used for sprinkling at high irrigation rates (500-800 cu m per hectare [m³/ha] and higher). Sprinkling devices with elongated shafts and pulse-action devices are used to increase the range of the sprinkler and to reduce the average spray intensity.

According to their principle of operation, sprinkling machines and installations are classified as positional and mobile types. Positional installations consist of a sectional distribution tube with hydrants and two sprinkling arms with short-range nozzles or medium-range devices. While one arm is operating, the second is transferred to a new position. The output of the installations is 0.28-0.30 ha/hr at an irrigation rate of 300 m³/ha. Positional short-range sprinkling machines have a two-arm sprinkling truss attached to the turret of a self-propelled caterpillar structure. The lower rib of the arm is a water pipe (its outer end is connected to a hydrant of the pipeline) with stub wings to which nozzles are attached. The output of these machines is 0.6-1.4 ha/hr. Positional long-range sprinkling machines (trailer, tractor-mounted, and self-propelled) are equipped with a centrifugal pump that sucks water from a temporary sprinkler and feeds it into long-range devices. A fertilizer tank is mounted on the machine for simultaneous feeding. The output of such a machine is 0.25-0.80 ha/hr. Mobile sprinkling machines consist of a two-arm truss with short-range nozzles mounted on a tractor. Water is taken from a temporary sprinkler by means of a centrifugal pump. Its output is 0.85 ha/hr.

Long-range sprinkling devices may be attached directly to hydrants of a stationary, closed drainage system for over-head sprinkling, which makes possible the automation of irrigation.