PRESSURE REGULATION
Because the regulators were set above the orange trees baking in the hot Florida sun, it was evident that more changes were needed in the plastic composition and the diaphragm makeup.
Expanding to pivots Regulator
showing the upper and
lower housing held together by stainless steel screws
Pressure regulators made their way onto center pivots during the 1970s. Healy went on to say, “At that time, all models were made up of an upper and lower housing held together by stainless steel screws. Around 1980, we were challenged by a very good customer to see if we could make a pressure regulator without screws holding it together. While the cur- rent models worked perfectly fine, if we could find a way to eliminate the need for screws, the product would be much easier to manufacture, and it would be tamper-proof.”
Healy recalls, “During the early ’70s, we broadened our range of models by using different springs to achieve specific outlet pressures. We changed to a white upper housing and printed the pressure rating using a hot-stamp pro- cess. Then we increased our production capacity by making multi-cavity tooling.” They also started making pressure reg- ulators with ¾- and 1-inch NPT connec- tions. With all the additional models and enhancements, pressure regulators became attractive to other markets.
Healy took the challenge and began working with engineer Bill McFadden, drafting out concepts and testing designs, much like he and Joe Senninger had done many years before. Eventually, they developed a design and assembly method using a specific plastic alloy. They were able to make a no-leak snap-together regulator.
The materials used to manufacture pressure regulators changed over the years to better resin blends that would resist chemicals like liquid fertilizers and withstand extreme temperatures like those found in expanded global markets.
Early no-leak snap-together regulator
“Initially, we molded unreinforced dia- phragms. However, we soon changed to a reinforced material,” Healy added. “Spring suppliers can now produce more accurate springs. Additionally, we have tightened the tolerances of both our molded and purchased parts.”
Years ago, to measure the accuracy, Healy used “hysteresis,” an electrical term simu- lating what happens inside a motor. The word caught on in the irrigation indus- try. Hysteresis refers to the difference in pressure regulator performance, while the inlet pressure is increasing versus decreas- ing. If a pressure regulator has very low hysteresis, this means it can maintain a very similar performance while the system pressure increases versus when it decreases. The lower the hysteresis, the more accurate the pressure regulator will be.
No pressure regulator is perfect, but those with the highest accuracy are
Because the regulators WERE set above the orange trees baking in the hot Florida sun, it was evident that more changes were needed in the plastic composition and the diaphragm makeup.
14 Irrigation TODAY | Winter 2021
Early hysteresis chart illustrating the difference in pressure regulator performance, while the inlet pressure is increasing versus decreasing
irrigationtoday.org
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