For manufacturers of pop-up spray heads, gear-driven and impact rotors, the performance of these products isn’t as easy to improve upon as it may have been five or 10 years ago.
Manufacturers admit there is still room for improvement in the performance of their products, but the product development improvements made across the industry have led manufacturers to place increased importance on a new priority for future changes the irrigation contractor.
The equipment that’s out there all works well, observed Jeff Carowitz, marketing manager, Hunter Industries, San Marcos, Calif. What we’re really looking at now is giving contractors the features they need to manage water distribution.
ROTO ROTORS. The benefits of rotors vs. spray heads are essentially undisputed. Rotors are much more efficient than spray heads in most applications, commented Carowitz. The rotors apply water at a rate that the soil can absorb it, whereas spray heads work in more of a controlled flood fashion.
And irrigation contractors have recognized these benefits. Although the greatest demand is still for the midsize heads in the 25- to 40-foot range, the demand for the short throw rotor is something we see as a growing market because a lot of contractors are looking for a product to cover larger areas while using less zones, agreed Chip Kah, president, K-Rain Mfg., Riviera Beach, Fla.
Dirk Lenie, residential/commercial marketing manager, Toro Irrigation, Riverside, Calif., noted that spray heads’ precipitation rates are often three or four times higher than rotors. With most systems, the rate is .2 to .4 gpm for rotors, compared to 1.4 gpm with pop-up spray heads.
| Contractor Comments |
The sprinkler heads available to today’s irrigation contractor are generally very effective products, according to some of those irrigation contractors. They said manufacturers are making more reliable products that suit most of their needs. But that doesn’t mean these sprinklers can’t be improved upon. The ability to get water closer to the heads needs to be improved, recognized Greg Kear, owner, Kear Construction, Doylestown, Pa. Most rotors can get water on turf 30 feet away, but they can’t get down three feet away. Unless you have perfect overlapping you end up with dry spots around the heads. What’s most important to us is that manufacturers come up with a small gear-drive head in the 18- to 25-foot range, added Nick Bowen, sales manager and irrigation division manager, ILT Vignocchi, Wauconda, Ill. There’s been a gap there for years. Of course, contractors warn that maufacturers should never reduce the quality of product they are producing today. Product choice is more an issue of reliability than anything, noted John Ossa, irrigation superintendent, Jensen Landscape Services, Cupertino, Calif. We’re happy to pay the higher price of a product if that product will stay in the ground longer. - Bob West |
Rotors are also much easier to install and they cover larger areas, added Carowitz in explaining the increasing popularity of rotors among contractors. However, rotors still face one primary issue before they’ll be able to overtake pop-up spray heads as the sprinkler of choice.
It’s a basic question of economics a rotary head sprays 15 feet for $15, but a contractor can do the same thing with a spray head that costs $3, Carowitz observed. If they want to use more rotary heads, contractors have to be able to justify the cost with improved application efficiency by taking advantage of the ability to use larger rotors on one valve and minimize the number of valves installed. This then also saves on the amount of piping and zones necessary for a job and the labor cost will go down.
They won’t change the amount of water contractors have to apply, but minirotors are just much more efficient than pop-up sprays if you look at the coefficient of uniformitites, Kah added. But I think the idea that spray heads are more efficient remains one of the biggest misconceptions in the industry.
UNDER PRESSURE. Pop-up spray heads can create additional problems with misting heads, or water that is forced out of the head at such high pressure that it ruins the distribution pattern and creates a mist pattern. This problem is leading more irrigation contractors to at least consider installing heads with pressure compensating devices, according to Lenie.
Pressure compensating systems should continue to be added to systems as water becomes valuable in order to achieve better distribution through better control, he noted, adding that such systems do tend to cost more. This gets to be more of a specified item right now, but as water gets more expensive we think the contractors will have to focus more on the misting problems.
Lenie added that much of the misting focus centers around pop-up spray heads because they mist at a lower pressure than rotors do. The rotors’ single streams are less susceptible to misting than fan spray distribution patterns are, he said.
PEOPLE POWER. All of the product improvements in the world are wasted if the individuals working with those products in the field don’t know how to use them.
Ease of adjustability is one of the most important things contractors are looking for with different heads, noted Carowitz. And that’s for when the system isn’t operating as well as when it is on.
Manufacturers seem to be addressing issues such as flow stoppage, which lets contractors shut down one head and replace a nozzle while the rest of the system is on, observed John Ossa, irrigation superintendent, Jensen Landscape Services, Cupertino, Calif. This lets us take advantage of the flexibility from different nozzles.
The author is Editor of Lawn & Landscape magazine.
| Surefire Selections |
Equipment selection, often done in haste, is critical to the long-term success of an irrigation system. Equipment that is high in quality and performance, low in maintenance, long lasting and water conserving represent the essential components of a quality irrigation system. Pop-up spray heads for turf areas should have a minimum pop-up height of 4 inches. This is necessary because of mowing heights required for turfgrasses. A 6-inch pop-up height is advisable adjacent to streets where the turf builds up faster. The 12-inch pop-up height should be used in ground covers and beds. These heads require a heavy-duty retraction spring to prevent damage by maintenance crews. A high quality wiper seal is necessary and important to prevent leakage around the stem and to minimize blow by when the stem pops up. The blow by or flushing action that occurs when the water is turned on cleans the wiper seal and flushes debris from the head. Heads should seal in the operating position at 10 PSI or less while the amount of water used in the flush mode should be minimized to conserve water. The cap on the top of the head that llows access to internal parts should have a tight seal. Some heads have caps that leak and require tightening in the field. This passage was excerpted from The Complete Irrigation Workbook, by Larry Keesen. To order a copy of this book, call Fran Franzak at 800/456-0707. |
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