The role of the spillway is to maintain a given pressure upstream of its position on the network.
What are the advantages for the installations?
The decisive advantage lies in the quality of compressed air delivered by air treatment equipment.
All these materials have a defined efficiency for a flow/pressure couple. Or, for example, for a filter of 100 m3 / h at 7 relative bars: 100 / (7 +1) = 12.5 m3 / h real (compressed).
What happens if the installation pressure falls below 7 bars?
At 5 bars, for example, the actual flow will be 100/6 = 16.7 m3 / h, which represents an overload of 33%.
At 3 bars, this same overload goes to 100% and the air flow speed is doubled !
However, such pressure fluctuations are sometimes more frequent than is believed on certain networks. (Repeated pressurizations, consumption higher than the compressor flow rate during flushing or unloading, for example..)
These overloads have catastrophic effects on the efficiency, proper functioning and lifespan of air handling equipment.
For filters :
- Decrease in filtration efficiency.
- Deformation / degradation of the filter media.
- Re-entrainment of oil or condensates downstream of the filter.
For adsorption dryers :
- Cycle disturbance, pressure too low for the actuators.
- Contact time too low, increase in dew point.
- Excessive speed of passage, production of desiccant dust.
For refrigeration dryers :
- Dew point drift.
- Re-entrainment of condensed water downstream of the dryer.
Having a spillway eliminates all of these problems. If the flow demanded by the use becomes greater than the production / treatment capacity, the overflow valve closes. The loss of downstream flow then reacts to the user and indicates the need to modify his installation. (Downstream air storage tank to absorb peaks, redefining or increasing production and processing capacity)
The spillway also avoids litigation and requests for unjustified guarantees. Since the flow consumed can no longer be greater than the processing capacity of the equipment, the quality of the compressed air is preserved.
