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Water tank
From Wikipedia, the free encyclopedia
Water tanks are storage containers for water, these tanks are usually storing water for human consumption. The need for water tanks is as old as civilized man. Water tanks exist in many forms and a variety of materials. Water tanks provide for the storage of drinking water, irrigation, fire suppression, agricultural farming and livestock, chemical manufacturing, food preparation and many other applications.
Various materials have been used for constructing water tanks: plastic, polyethylene, polypropylene, fiberglass, concrete, steel (welded or bolted, carbon or stainless). Earthen ponds are also often referred to as tanks. Description of water tanks to the left on a current municipal water storage tank system: Hydro-pneumatic water tank, an AWWA lined carbon steel pressure vessel, is designed to provide pressurized water to the distribution system. Chemical contact tanks of FDA and NSF polyethylene construction allow retention time for water and chemicals to be in contact and mix.
A large ground water tank is made of lined carbon steel, it may receive water from well or surface water allowing a large volume of water to be placed in inventory and used during peak demand cycles. Very large water tanks may be either elevated or may sit flat on the ground. Elevated tanks create a distribution pressure at the tank outlet of 1 psi per 2.31 feet of elevation, thus a tank elevated to 70 feet creates about 30 psi of discharge pressure, 30 psi is sufficient for most house hold requirements.
The profile of a water tank begins with the application parameters, thus the type of material used and the design of the tank will be dictated by these variables:
1. Location of the water tank (indoors, outdoors, above ground or underground)
2. Volume of water tank will need to hold
3. What the water will be used for.
4. Temperature of area where water will be stored, concern for freezing.
5. Pressure required to deliver water
6. How is the water to be delivered to the water tank.
7. Wind and Earthquake design considerations allow water tanks to survive seismic events.
Throughout history, wood, ceramic and stone have been used as water tanks. These were all naturally occurring and manmade and some tanks are still in service.
The Indus Valley Civilization (3000–1500 BCE) made use of granaries and water tanks.[1] Medieval castles needed water tanks for the defenders to withstand a siege.[2]] A wooden water tank found at the Año Nuevo State Reserve (California) was restored to functionality after being found completely overgrown with ivy. It had been built in 1884.[3]
Vertical cylindrical dome top tanks may hold from fifty gallons to several million gallons. Horizontal cylindrical tanks are typically used for transport, low-profile storage. Hydro-pneumatic tanks are pressurized storage tanks. By pressurization this resevoir of pressurized water creates a surge free delivery of stored water.
There are many custom configurations that include various rectangular cube shaped tanks, cone bottom and special shapes for specific design requirements.
A functional water tank/container should do no harm to the water. Water is susceptible to a number of ambient negative influences, including bacteria, viruses, algae, changes in pH, and accumulation of minerals. Correctly designed water tank systems work to mitigate these negative effects. Articles on Water Tank application and design considerations.
American Water Works Association The AWWA provides specifications for a variety of water storage tank applications. The AWWA's site will provide scientific resources which will give the reader an informed perspective on which to make decisions.
NSF International writes standards, inspects and confirms that products such as air, food, consumer goods and water are suitable for human consumption.
The Food and Drug Administration approves materials for use in storing water and food materials. Consult the Code of Federal Register for more details on water tanks.
Flight simulators use elaborate water tanks for the simulation of weightlessness. Water tanks fabricated to resemble space craft interiors are suspended in large swimming pool like environments, giving astronauts the feeling approximating zero gravity.
The Airline industry uses elaborate water tanks to simulate, aircraft emergency water landings and the performance of the airplane upon entry to the water.
