Fundamentally, there are three methods by which compressed air can be distributed from the compressor system to point of use;
- Compressed air branch line; Compressed air branch line systems are usually best suited to small businesses. As the name implies, compressed air is distributed out through pipes which branch out from the main line. The length of the piping required for the branch lines is comparatively short. However, it must have sufficient capacity to meet the system's entire compressed air demand. As a result the pipe diameter needs to be significantly larger than it would be in a ring main or distribution network. In addition, as there will be an increased distance from the main compressed air supply, the connection lines to the points of use also have to be larger. One drawback of this network is that it does not allow for individual sections of the system to be shut-down in order to enable system expansion or cleaning work. As a result the whole compressed air system would have to be shut down for these purposes.
- Compressed air ring main; Compressed air ring main systems are more complex to install, however they have one large advantage over a branch line system. That being that if all points of use have the same compressed air demand, the connection pipe length and volume can be reduced by half. The result is that smaller diameter piping can be used whilst the capacity remains the same. Connection lines within a ring main system are also very short.
A sufficient number of shut-off units can also be included in a ring main design to allow for certain sections of piping to be taken out of operation for cleaning and expansion whilst leaving the rest of the compressed air installation to operate as normal.
- Compressed air distribution network; A compressed air distribution network is often the perfect solution for companies with large facilities. A distribution network system has a very similar design to a ring main system but it includes additional longitudinal and cross connections. It is the most complicated to install, however it brings a number of key advantages!
The network design provides a reliable and energy efficient supply of compressed air to large production halls requiring no excessively large pipe diameters. In fact, dimensions can actually be kept to a similar size as those in a ring main system installed in a small or medium sized business. And, as with a ring main system, individual sections of a distribution network can also be shut-down as required.
The ideal compressed air distribution system will depend on a number of individual factors however, the goal will always be the same; to supply all points of use with sufficient compressed air at the required pressure. Why? Because, keeping the system running at the required pressure will contribute to its overall efficiency!
As compressed air flows through a pipeline network, friction is created. This friction results in a pressure drop. And a pressure drop will reduce the efficiency of the compressed air system. Similarly, if you were to set the pressure higher by even 1 bar to compensate for a pressure drop, you would increase the energy consumption of the compressor station by around 6% and also sharply increase the probability of leakage. Care should therefore be taken to ensure that the pressure drop does not exceed 0.03 bar.
As a result, when designing a compressed air network, it is also important to consider factors which will keep any pressure drop to a minimum, such as;
- consider the distance the air must be transported and if possible reduce it
- reduce friction by increasing pipe size and removing any unnecessary valves and elbows
- consider the length and diameter of piping required; longer pipes and pipes with a smaller diameter generally incur higher pressure drops
- continuously detect and eliminate compressed air leaks.
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