In what types of installations can I use centrifugal pumps?

Open pump systems

With an open pumping system, the fluid must be pumped from a low-lying supply reservoir to an elevated reservoir. The pump transports the water from the lower reservoir to the desired height.

It is not sufficient to adapt the flow rate of the pump to the geodesic head because at the last tapping point, e.g. a shower on the top floor in a hotel, the pressure should still be high enough. The friction losses that arise in the ascending pipe must also be considered.

Pump head = geodesic head + pressure + pipe losses

For necessary maintenance work, the individual pipe segments must be able to be closed off by means of taps. This applies in particular to pumps because otherwise enormous quantities of water will have to be drained from the ascending pipes for repair or replacement of the pump.

Float valves or other control elements must also be provided in the lower supply tank and in the upper tank to prevent any overflow.

In addition, a pressure switch can be installed in the ascending pipe at a suitable location which switches off the pump when all draw-off points are closed and no more water is drawn off.

Closed pump systems

While a water pump system is an open system with a free outlet (for example, a tap in the form of a faucet), a heating installation is a closed system.

This principle is even easier to understand if we imagine that the heating water in the pipes is simply keeps moving or circulates.

The heating system can be divided into the following elements:

• heat source;
• heat transport and distribution system;
• diaphragm expansion tank for maintaining and controlling pressure;
• heat consumers;
• control system;
• safety valve.

Heat sources here refer to heating boilers and such, on gas, oil or solid fuel. This also includes electric night-time heaters with central water heating, district heating stations and heat pumps.

The heat transport and distribution system include all pipes, distribution and collection stations and of course the circulator. The pump capacity in a heating installation must only be designed in such a way that all resistance, such as bends, fittings, pipe diameters of the installation are overcome. The height of the building is not taken into account because the water that is forced into the supply pipe by the pump pushes the water in the return pipe back to the boiler.