You create water pressure with gravity by storing water at a higher elevation than the point of use; the height difference creates pressure.
Here's a breakdown of how it works:
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The Principle: Gravity pulls the water downwards. When water is stored in a tank or reservoir at a certain height, the weight of the water above exerts pressure on the water below. This pressure is what forces the water through pipes.
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Height is Key: The higher the water source is located relative to the outlet, the greater the water pressure. This is because the column of water above exerts more force. A general rule is that for every 1 foot of elevation difference, you get approximately 0.433 psi (pounds per square inch) of pressure.
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Practical Implementation:
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Elevated Tank: A common method is to use an elevated water tank. Water is pumped into the tank, and gravity then provides the pressure to distribute the water to homes, businesses, or irrigation systems.
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Natural Elevation: If you have a natural water source (like a spring or well) located on a hillside, you can use gravity directly without needing to pump the water to a tank first (assuming sufficient elevation difference).
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Calculating Pressure: As mentioned, approximately 0.433 psi is generated per foot of elevation difference. For example, if your water tank is 50 feet above your faucet, you would have roughly 21.65 psi (50 x 0.433 = 21.65).
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Considerations:
- Tank Size: The size of the tank determines the volume of water available, not the pressure.
- Pipe Diameter: Pipe diameter affects flow rate. Narrower pipes restrict flow, potentially reducing the effective pressure at the outlet, especially when multiple outlets are in use.
- Friction Loss: Friction within the pipes also reduces pressure over long distances.
In summary, by elevating a water source, you harness gravity to create water pressure, making it a simple and reliable system, particularly in areas where electricity may be unreliable or unavailable.
