April 1 2006 12:00 AM


Technology has evolved rather quickly in the last twenty years. Many of us cannot imagine a world without computers, compact disc players and cell phones, but in the world of irrigation, technology moves at a different pace. When was the last time you heard about innovations in irrigation that would change the industry? Now may be that time.
Several recent innovations in valve technology have been created that could alter the way we think about watering systems. Three different types of valves, two recent inventions and one relatively unknown, have the unique advantage of operating without electricity. One method allows you to control an average-size watering system with the power generated by a palm-size solar panel.
The second type is a valve that has the ability to turn an individual sprinkler head on and off in any combination of the eight settings of a watering cycle. The third valve, developed some years ago and used in limited markets, can be programmed to divert water to any one of six zones. It may sound confusing, but the innovation all three share is that they are controlled by pressure from the main water line. Operating in different ways, they change the direction of the water flow by merely turning the water supply off and on.




Shown on left:
Sturman BG's Toggle Valve
Photo courtesy: Sturman BG, LLC





Digital Magnetic Latching and Toggle Valve

The first set of valves, called the . Digital Magnetic Latching. and . Toggle. valves, were developed by Eddie Sturman of Sturman BG Industries of Woodland Park, CO. They center around digital technology, the same digital technology used in computers and compact disc players. These innovations started more than twenty years ago when Eddie Sturman developed digital latching valves for NASA.

The digital magnetic latching valve is a low-voltage, highly accurate valve that controls the water pressure sent down line to the different watering zones. The technology of this valve played an important role in the space program.

Some people speculate that the low voltage used by this valve made a difference in saving the lives of the crew members in the power-drained Apollo 13 space flight. Not only does this type of valve use very little power, but it is so accurate that it is used in the fuel injection systems of diesel engines built by Navistar.

What completes this system is the second development, the toggle valve. The toggle valve used at each watering zone, simply either diverts water into that watering zone or sends it down line to the next zone. This toggle valve is mechanical, it uses no electricity but opens and closes in response to water pressure. One of its major advantages is that since it diverts water rather than stops water like traditional valves, it has a wider internal passage that helps prevent dirty water from clogging it.

The system works like this: say you have nine watering zones, each connected to the main line, one after another in sequence. The digital controller is at the head of the water main. Now it. s time to water. The controller opens and sends water down the line. The first toggle valve diverts water to zone one and waters as long as needed. Next, the digital controller stops the water pressure, and the toggle valve responds to the lack of pressure. It closes the outlet to zone one and opens to allow water to flow to the next toggle valve down the line. When the digital controller turns the pressure back on, the water passes through the first toggle valve to the second toggle valve where it waters zone two. Zone two waters as long as needed and then again the digital controller shuts the pressure off and the cycle repeats until all zones have been watered. After all nine zones have been watered, the controller shuts off the pressure, and after a minute and a half all the toggle valves reset to their original position.

The system. s main limitation is that all the watering zones have to be lined up in sequence. Starting at the main digital controller, the first zone down the pipe line has to water first, then the second zone runs, the third and so on. Although it. s possible to program zones out of sequence, it. s not easy. To program the third zone first, for example, you would have to run through a cycle that turns on zone one and two very briefly, then go on to zone three.

How the main controller, the Digital Magnetic Latching valve, opens and closes using so little electricity is not clear. With this digital valve, once an impulse moves the valve open, it stays open. Once an impulse closes it, it stays closed. Obviously, it takes less power than traditional systems, but how much less? A normal irrigation system operates from the power generated by a solar panel about the size of a postcard.

Programmable Valve
The Programmable valve is another innovation that uses no electricity. This valve can be programmed to open and close in any combination of settings based on a cycle of every seven times the water is turned on. It is small enough to be installed under a sprinkler head, or in another version, can be used in a water line. This innovation means that each sprinkler head can be programmed to open at different times than the others in the same zone.

The Programmable valve was created by George Beauchemin, an engineer, in a burst of inspiration while sitting in a nursery seminar. An audience member asked the seminar leader about planting an orange tree in a row of avocado trees. The expert said it can. t be done. He explained that the watering needs of the two types of trees differed so dramatically, you would have to install a new water line for the orange tree. George Beauchemin said to himself right then that he could make a special valve to solve that problem. For the past two years he has been hard at work creating and perfecting the valve.

He conceptualized a mechanism inside the valve that is triggered by water pressure to advance the cycle one setting. At each setting the valve can be programmed to open or close. Each cycle has seven settings.

With this valve installed in the grove of trees, each watering line to a tree can be programmed to open in different cycles than the watering line of all the other trees. The lone orange tree can be programmed to open three out of the seven times that the other avocado trees are watered. Or it can be programmed to open one out of seven times. If reversed, say instead of the avocado trees, the young orange tree was to need more water, the other trees can be programmed to come on, say, four of seven times the young tree is watered. We commonly try to solve this problem today by decreasing the amount of water coming out of the emitter head, but this may not give the tree the deep watering it needs.

This valve works in cycles based on water being turned on and off. Every seven times the water pressure reaches the valve, it completes a cycle. Think of a rotor turning one-seventh of a turn every time the water main is turned off and on. Now imagine that every time the rotor turns that one-seventh of a turn, you can program the valve to let water flow through or have it shut. This means you can have any combination you want. In all seven settings of the cycle, the valve can be opened or closed. You can open it on odd numbers and close it on even numbers. You can open it on the third and fifth setting and close all the others. Every time the water main is turned on and off, the rotor advances one step to the next setting.

What makes this valve practical is its simplicity of design. With very few moving parts, it. s small enough to be installed under a sprinkler head. When produced, it should be inexpensive enough so it can be installed at individual sprinklers. Its applications are enormous. Anytime watering needs differ in a watering zone, a programmable valve can be used. In gardens where plants change from season to season, one can alter the watering requirements by programming the valve. If, as a plant matures, its watering requirements differ from those of others on the water line, you merely re-program the valve. If, for example, you install a patch of new turf, which may need watering two or three times more often than old turf, you merely program all the valves. In short, this valve gives you more control over the individual sprinklers and watering lines in a zone without having to buy expensive, battery-operated solenoid valves or run separate watering lines.

Indexing Valve
The third type of valve that uses no electricity to operate is the indexing valve. Unlike the Sturman valves and the programmable valve, this valve is already on the market, and found in wide use in Florida. It was developed by K-Rain Manufacturing, Riviera Beach, FL. Although another company in Florida has a similar valve, both seem to have evolved around Carl Kah, founder of K-Rain.

This indexing valve is widely used in Florida because of the availability of ground water. Close to half of the residential and small commercial watering systems in Florida pump water from shallow wells rather than using municipal water. In California, by comparison, 99 percent of irrigation systems use municipal water. Because the water is pumped, a special valve is needed to direct water to different watering zones.

Traditional solenoid valves create complications because they have to open at the same time the pump runs. If the two are not always synchronized, then the pump may be running with no water outlet for the pressure. A common experience with this system is that after a power outage, the controller automatically resets into a default mode. In the default settings, the controller runs every station and can . dead head. the pump, causing severe damage. This is where the indexing valves take their place. These valves direct water to different zones and are controlled by the water pressure, or in this case, when the water pump is turned on.

Where the toggle valve diverts water in only one of two directions and the programmable valve closes or opens, the indexing valve directs water to any one of six outlets. Like the other valves, the indexing valve advances the cycle with changes in the water pressure. Each time the water is turned on, or the pump is on, the valve changes the direction of the water flow from one outlet to another. Water will first come to outlet one, then with the pressure off an internal wheel turns, and when the water pressure comes back on it will go to outlet two. This will continue in a cycle of up to six outlets. The indexing valve can be programmed with as few as two of the outlets, if desired.

K-rain offers two sizes, a four-outlet and six-outlet valve. With a pump timed to come on for zone watering, and delays between zone times to stop pressure, the system is complete.

The indexing valve has also found usage with . on-site. waste water disposal systems. This is a new breed of septic tank that aerates waste water and purifies it so cleanly that in some parts of the United States, it flows through the sprinkler systems. When water is pumped out of this system, either in a sprinkler system or underground, it needs a valve to distribute it. Since the water is pumped out randomly, conventional solenoid valves do not work well. With the indexing valve, each time the pump comes on, the treated water will shift to a new watering zone or underground outlet.



A solar-powered controller
has no batteries, yet can throttle
a magnetic-latching valve in a
field irrigation system.


Of the three systems, only the indexing valve is presently being marketed through wholesale irrigation supply houses. The creators of the Sturman valves and programmable valve have prototypes, and are in the process of teaming up with manufacturers or securing licensing agreements for their patents. All three valves are innovations that could, in future years, serve as an essential component in the irrigation industry. For now, with the exception of the indexing valve, all we can do is wait and think towards the future.

Editors Note: As water shortages become more widespread and prices increase, the irrigation industry is constantly seeking new ideas and ways of making water more efficient. Although two of the above-mentioned products are not yet in production, it does give one food for thought.