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 Fig. 8.3: Behaviour of pressure in a compressed air receiver | The receiver pressure, which fluctuates between p min and p max , must always be much higher than the operating pressures of the consumer devices in the network. Pressure loss always occurs in pneumatic systems. This is why the pressure loss caused by the various components of a pneumatic system must be taken into consideration.
The following values must be considered when defining the cutout pressure p max :
- Normal pneumatic networks £ 0,1 bar
The network should be designed so that the total pressure
loss Dp of the entire network does not exceed 0.1 bar.
- Large pneumatic networks £ 0,5 bar
On widely branched networks, e.g., in mines, quarries or large building sites, a pressure loss Dp up t 0.5 bar can be allowed.
- Treatment of compressed air by dryer.
Diaphragm compressed air dryer with Filter £ 0,6 bar
Refrigeration compressed air dryer £ 0,2 bar
Adsorption compressed air dryer with filter £ 0,8 bar
- Compressed air treatment by filters and separators.
Dust separator £ 0,05 bar
Filters generally £ 0,6 bar
The pressure loss Dp through filters rises from soiling. The
latest time at which the filter must be changed is specified.
- The cycle difference of the compressor.
Screw compressors 0,5 - 1 bar
Piston compressors pmax - 20 %
- Reserves.
Unforeseen pressure loss occurs time and again in pneumatic
systems. An adequate contingency reserve should always be planned for in order to avert performance loss.
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