Sometimes called a check valve or a backflow preventer, a chemigation valve is an apparatus designed to protect water supplies from

agricultural chemical An agrochemical or agrichemical, a contraction of ''agricultural chemical'', is a chemical product used in industrial agriculture. Agrichemical typically refers to biocides (pesticides including insecticides, herbicides, fungicides and nematicide ...

s used during

chemigation Fertigation is the injection of fertilizers, used for soil amendments, water amendments and other water-soluble products into an irrigation Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of ...

, the application of chemicals such as

fertilizer A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Man ...

s and

pesticide Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...

s through

irrigation Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has bee ...

water. Most chemigation valves consist of a spring-loaded

check valve A check valve, non-return valve, reflux valve, retention valve, foot valve, or one-way valve is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction. Check valves are two-port valves, meaning they have ...

, a low pressure drain, an air and vacuum relief valve, and an injection port for introducing the chemicals downstream of the check valve. Many chemigation valves also have a 4-inch inspection port so that a person can reach inside and feel if the check valve is still functional. Some governments require the use of two chemigation valves installed in series if hazardous chemicals are to be injected. The following policies require or encourage the installation of these valves: Texas State law Chapter 344.73 in Subchapter D - 1.(b) : "An irrigation system which adds any chemical is considered to be a 'high health hazard'. Such an irrigation system must not be connected to any

potable water Drinking water or potable water is water that is safe for ingestion, either when drunk directly in liquid form or consumed indirectly through food preparation. It is often (but not always) supplied through taps, in which case it is also calle ...

supply except through a reduced pressure principle backflow prevention assembly." Florida's Department of Agriculture and Consumer Services Water Quality/Quantity Best Management Practices for Florida Specialty Fruit and Nut Crops p. 20 specifies that: : "Backflow prevention should include a check valve between the irrigation pump and the injection device to prevent backward flow; a low-pressure drain to prevent seepage past the check valve; a vacuum relief valve to ensure that a siphon cannot develop; and a check valve on the injection line."

References

Plumbing valves Irrigation Backflow {{Agri-stub

See also

References