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Pressure switches in booster pumps

The invention of the pump itself was a significant breakthrough for mankind. It significantly simplified the supply of drinking water. With growing demands for a well balanced water supply, largely free from pressure fluctuations, and at the same time increasing demands on the energy efficiency of buildings, pumps are actually making their contribution as booster pumps. What their task is, how they function and what pressure switches do along the way is explained briefly and succinctly in this article.
What exactly are booster pumps needed for?
A booster pump increases low water pressure and, with that, improves the flow rate. It provides an extra boost to bring the water pressure to the desired level. Booster pumps tend to be used in pipelines to increase the pressure therefore to go the liquid along to the next pump, and in addition for pumping in residential houses or large commercial buildings. An expansion vessel can extend a pressure booster system. By using this expansion vessel, the water pressure is additionally stabilised and therefore improved.
Booster pumps in operation
The figure gives an overview of the different measuring points inside a pressure booster system:
1 Input pressure ? Pressure
2a Dry run protection ? Pressure
2b Dry run protection ? Level
3 Output pressure ? Pressure
4 Pump performance ? pressure gauge
How does a booster pump work?
Booster pumps are selected based on application demands. Instead of selecting one large pump, consider selecting multiple pumps with smaller horsepower. Booster pumps have an impeller that moves water that will come in through the inlet and exits through the outlet. A motor makes the impellers spin. The pumps differ in how they draw the water in and push it out. A number of them work with a spinning propeller, others use an oscillating diaphragm or other pump principles.
What do mechanical pressure switches in booster pumps do?
The mechanical pressure switches in booster pumps are used for the direct control/monitoring of safety functions in order to protect pumps with insufficient input pressure against dry running. A good example of this can be the WIKA PSM-520 pressure switch.
Just how do mechanical pressure switches work?
The pressure part of the switch is really a resilient bellow which works against a spring mechanism having an adjustable pre-load force. On the spring mechanism there is a contact arm for actuating the change-over switch contact. The switch is actuated as soon as the force generated by the pressure in the pressure element is greater than the set pre-load force.
Note
Further information on the many measurement solutions which you can expect you for pumps and systems are available on the WIKA website. For those who have any questions, your contact will gladly assist you to.
Also read our articles
Mechanical pressure switches: So how exactly does one set the switch point?
Mechanical vs. electronic pressure switches: Functionality
Further blogs on mechanical pressure switches