What should be the size of air receiver for-compressor delivery 55cfm / 10 bar: -required flow rate of 200 CFM in open ckt. -required flow from 4 inch dia pipe from air receiver 200 CFM at 7bar 60 degree C -the flow should be constant for at least 2 minute
An air receiver is one of the most underrated items of equipment in the air system. The vessel provides a buffer between the compressor and system to enable the compressor to receive a smooth, clean pressure signal. The vessel volume has a direct impact on the number of load / unload (or stop/start) cycles which impacts wear and tear on the control system and motor starter as well as the overall energy consumption. It is therefore imperative that the vessel be sized correctly.
As a rule of thumb a vessel should be a minimum of 10litres for every L/sec discharge from the compressor. i.e. a 55cfm or 26L/sec should have a vessel no smaller than 260 Litres. However, the system described above, assuming a minimum system pressure of say 5 barg, would require an air receiver of minimum volume 1650Litres (assuming the compressor is running while air is required for the process). If no make up air is available the vessel would need to be 2260 Litres. The vessel recovery time would be around 5.5 minutes. (based on the smaller vessel). This all assumes that air is not being used anywhere else in the plant at the same time.