How does a pressure tank work?

Pascali Self Priming Jet Pump with 24L Steel Pressure Tank

Written by admin

October 25, 2021

You will often see a pressure pump sit on top of a small pressure tank in domestic setups. This tank is not just to keep the pump and motor off the ground but plays an important role in the way your pressure pump system functions. 

– How does it work?

Air can be compressed, water cannot. The pressure tank, which is typically 24 litres in capacity stores water and compressed air, separated by a rubber membrane or bladder. The air pressure inside the pressure tank can be adjusted to the desired level at which the system should operate. A pressure tank is usually installed with a mechanical pressure switch, which will switch the pump on if the pressure drops after a tap is open for long enough and will switch off again when a pre-determined pressure is reached. 

– What a pressure tank does

When a tap is opened for a short while, like filling a glass of water, the air pressure in the tank will push the water out and the pump won’t have to switch on. If a tap is kept open for longer, like running a bath, the pressure will drop and the pump will switch on to restore the pressure to the pre-set level. 

– Benefits of a pressure tank

Some of the benefits of a pressure tank is that your pump won’t have to switch on every single time someone opens a tap. This saves electricity and reduces wear and tear on the pump motor. Another benefit is that there is a larger amount of water that is already under pressure compared to a system without a pressure tank. This pressurised water is available even in the event of a power failure. 

Because water cannot compress there is a phenomenon called the water hammer effect. This happens when fast flowing water comes to a sudden stop, like a closed tap. The water crashes into this obstruction with a significant force. There is a massive amount of energy locked up in moving water and the water hammer effect can really cause some damage. The pressure tank with an air compartment serves as a shock absorber, alleviating the hammer effect on your entire system, because the air can be compressed to dissipate the energy. 

If you have any more questions or you need a qualified professional to install your pressure pump system, don’t hesitate to contact the technical people of Pascali for assistance. 

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