water control valve
water control valve are drip irrigation valves that turn on and off water to the drip tubes (or hoses). Often these valves are automatically turned on and off by an irrigation controller/timer.
For a small drip irrigation system you may need only one zone control valve. While for bigger drip irrigation systems several more may be required.
There are two basic types of zone control valve: standard globe valve and anti-siphon valve.
Standard globe valves can be found in almost any size. They are often installed below the ground, kept inside a box or a vault. Since a standard globe valve does not incorporate a backflow preventer, you must provide one on your own.
Anti-siphon valves can be found in 20mm (3/4 inch) and 25mm (1 inch) sizes. They are most recommended for home gardeners since they incorporate a backflow preventer, thus saving a considerable amount of money. The valves must be installed above the ground, at least 150mm (6 inch) higher than the highest drip emitter. This requirement may be a problem for certain areas, but you can always install anti-siphon valves on top of trellis or at the top of the slope (if you have a garden with slopes).
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2011-05-30