Pressure Regulators Can Improve Your Pivot Irrigation Efficiency

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Date: 
Wednesday, August 18, 2021

Pressure regulators ensure that your pivot irrigation system operates the way it is designed. They also help prevent water waste, a critical factor in today’s water-stressed environment.

The correct water pressure is key to achieve optimal distribution uniformity and proper flow through the emitters running along a pivot line. Crops need the right amount of water at the right time, and pressure regulators help ensure this happens.

Sprinklers are manufactured to operate within a specific range of flows and pressures. Under these conditions, they maintain their distribution pattern, throw radius and droplet size. If they operate outside these parameters, their distribution patterns and application rates will be altered, causing over or under-watering. Also, they will have a shorter lifespan, making your investment less profitable.

This can also cause uneven fertilizer and chemical application through the system. As a result, crop growth will be affected, and yields will be lowered.

Correct water pressure is key to achieve optimal distribution uniformity

Today, pivot irrigation systems that are more efficient use low-pressure sprinklers and pressure regulators that provide significant savings in energy and water costs. Low-pressure sprinklers like Senninger Wobblers or LEPA bubblers help lower energy costs and save water by reducing wind drift, evaporation, and runoff. Lower pressure translates into reduced horsepower requirements and less energy consumption. It can also reduce wear-and-tear on the machine and system components.

Low-pressure sprinklers like Senninger Wobblers or LEPA bubblers help lower energy costs and save water by reducing wind drift, evaporation, and runoff.</p>

How Do Pressure Regulators Affect Flow Rate?

Most people know pressure impacts flow, but did you know that all it takes is a small pressure change of ~20% to create a ~10% flow variation? Pressure regulation is particularly important in low-pressure systems, where a slight pressure variation can have a significant impact on the application rate. For example, a pressure variation of 2 psi (0.14 bar) on a sprinkler designed to operate at 10 psi (0.69 bar) is equivalent to a 20% pressure variation. This alters the flow by 10%.

How Pressure Impacts Flow in an Irrigation System

How Long Do They Last

Though regulators can last for years, the degree of regulation will change over time as internal parts begin to wear. That means that regulators installed on systems that run for long hours throughout the season will wear faster than those on systems that run for fewer hours. Some experts recommend replacing regulators when they reach 10,000 hours of operation. 

Factors that contribute to wear include:

  • Poor water quality
  • Unflushed chemicals in the pipeline
  • Abrasive materials in the water
  • Long operating hours

What Are The Main Signs Of Wear?

Malfunctioning pressure regulators can be difficult to identify visually. However, some emit water through the sides of the regulator when they fail structurally. Sometimes they also produce a high-pitched squealing. 

A malfunctioning regulator can result in a sprinkler pressure that will be too high. A sprinkler emitting a finer spray or exhibiting a faster rotation speed relative to adjacent sprinklers may indicate a regulator is operating above its nominal rating. If operating below its nominal rating, sprinklers will produce larger droplets and slower rotation speed, as well as reduced wetted diameter.

During the irrigation season, farmers should intermittently observe sprinkler performance. This is best done either early or late in the day when the sun is low. Differences between sprinklers are easier to identify in this light. On center pivots, the number of acres affected is greater if worn regulators are located on the outer spans of the machine. 

The end of the season can be an ideal time to remove pressure regulators and check for any obstructions that may cause flow restrictions or distort the sprinkler distribution pattern.

How Do You Test Pressure Regulators?

All farmers should check their pressure regulators at least once every three years. You can test pressure regulators by installing a high-quality pressure gauge on each side of the regulator. 

The gauge on the inlet side assures there is enough pressure for the regulator to operate. Remember that inlet pressure should be at least 0.34 bar (5 psi) above the pressure regulator rating for the regulator to function. The gauge on the outlet side (after the regulator) should match the preset pressure printed on the device, allowing for slight variation due to flow.

If your irrigation dealer has a regulating testing device, you can also check the readings on a new pressure regulator that matches the model you are testing.

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