Sprinkle Of Truth

Short answer: The sprinkler in the footage is an impact sprinkler, the classic 'tick-tick-tick' design on farm risers. Water under pressure leaves the main nozzle as a jet.

A spring-loaded drive arm sits in front of it with a small deflector, or spoon, that dips into the stream. The jet knocks the arm aside, the spring swings it back, and it strikes the sprinkler body. Each strike nudges the head around a few degrees, so the jet sweeps a circle (or an arc, with trip stops) in small, even steps. Breaking up the stream this way also spreads the water more evenly across the wetted area. Other rotary sprinklers use a turbine or gear drive instead, as the Reel says. Orton Englehart, a citrus grower in Glendora, California, built the horizontal-action impact drive sprinkler in his shed around 1932 to 1933. His neighbor Clem LaFetra urged him to patent it. The application was filed on December 18, 1933, and US Patent 1,997,901 was granted on April 16, 1935. Englehart preferred farming and sold the rights to Clem and Mary LaFetra, who began production in their family barn on October 13, 1935, under the name Rain Bird. In 1990, the American Society of Agricultural Engineers named the Rain Bird impact sprinkler a historic landmark of agricultural engineering, crediting it with helping sprinkler irrigation spread to more than 50 million acres worldwide. The footage shows an impact sprinkler on a tripod stand in a sandy field, its arm swinging as the jet sprays across the sand.

In collections:Engineering Oddities