Pressure tank

Pressure tank - is designed for storing hydraulic energy of water and its subsequent use. The pressure tank in a water supply system acts as a damper, capable of absorbing both volume increase or a sudden pressure spike, and compensating for small water draws to reduce the frequency of pump activation.

Water is a virtually incompressible liquid, so even a minor leak in the water supply system or momentary opening of a tap will reduce pressure and trigger the pump. Even a small volume increase caused by heated water expansion can lead to a sharp rise in pressure, potentially damaging the components of the water supply system.

The working principle of the pressure tank is based on storing hydraulic energy of water for later use. When the pump operates, part of the energy is spent on compressing the air filling the internal volume of the tank and filling it with water. After the pump is turned off, the compressed air maintains pressure in the water supply system, and small water withdrawals are compensated by the water expelled from the tank.

Application

Pressure tanks are used in cold and hot water supply systems for:

• Maintaining pressure in the water supply system.
• Storing water in systems with intermittent water supply.
• Compensating for thermal expansion caused by water heating.
• Compensating for water hammer caused by pump activation.
• Compensating for small water draws or leaks that cause excessively frequent pump activations.
• Smoothing out water consumption peaks in systems with limited instantaneous water flow.

Alternative Names

• Hydropneumatic tank
• Buffer tank
• Damper tank
• Expansion tank for water supply

Possible Replacements

• The pressure tank can be replaced with an expansion tank, but note that expansion tanks are designed for hot technical water and are equipped with a less elastic membrane.


• An open reservoir installed at the highest point of the water supply system, with pump activation and deactivation signals sent from level sensors installed in this reservoir. This system is quite complex to implement and is usually only used for storing large volumes of water. An example of an open reservoir is a water tower.