Plastic Impact Sprinkler(Rotarying Sprinkler)

An impact sprinkler (sometimes called an impulse sprinkler) is a type of irrigation sprinkler in

which the sprinkler head, driven in a circular motion by the force of the outgoing water, pivots on

a bearing on top of its threaded attachment nut. Invented in 1933 by Orton Englehardt, it quickly

found widespread use.

Though it has in many situations been replaced by gear-driven "rotor heads", many varieties of

impact sprinkler remain in use.

The sprinkler head pivots on a bearing on top of its threaded attachment nut. The head is driven

in a circular motion by the force of the outgoing water, and at least one arm extends from the

head. The sprinkler arm is repeatedly pushed back into the water stream by a spring.The arm's

striking the water stream scatters the stream and re-orients the flow slightly, enabling a uniform

watering area around the sprinkler.

Some full-circle impact heads feature a second, short range, opposing "spreader" nozzle, which

fills the close  range watering coverage role provided by the rapid "return cycle" on part-circle

heads.

By adjusting the position of the limiting collars, water flow can be directed from a full-circle

pattern to one of less coverage. The limiting collars are fully adjustable by twisting with fingers

to achieve the area of coverage desired.

The uninterrupted flow path of impact heads makes them less vulnerable to damage and clogging

by dirt and sand in the water. Thus, they are suitable for systems fed by wellwater. One defining

feature of impact heads is they almost always have male pipe threads, as opposed to the female

threads found on virtually all other sprinkler types.

The sprinkler head was originally manufactured from metal. Since the 1970s, they have been 

manufactured from thermoplastics for improved corrosion resistance.

The impact sprinkler's long spray radius and uniform water distribution re-creates the effect of

natural rainfall, and the device quickly replaced,the centuries-old technique of furrow irrigation,

in which trenches were dug between rows of crops and flooded.