Does your Plant have enough Air Storage?
One common issue with a compressed air system is fluxuations in the pressure, especially during peak demands or events. This is often due to air receivers that are undersized or improperly placed in the system.
How do you size an Air Receiver?
The old way to size an air receiver was 1-2 gallons per CFM. This was fine for older technology, but not adequate with today's modern air compressors. Here is the proper way to calculate the minimum receiver capacity:
V = T(C - Cap)(Pa)
______________
(P1 - P2)
Where,
T = Time interval in minutes, during which a receiver can supply air without excessive drop in pressure
V = Volume of receiver in cubic feet
C = Air requirement in cubic feet of free air per minute
Cap = Compressor capacity in cubic feet of free air per minute
Pa = Absolute atmospheric pressure, psia
P1 = Initial tank pressure, psig (compressor discharge pressure)
P2 = Minimum tank pressure, psig (minimum pressure required to operate plant)
If the capacity of the compressor (Cap) is greater than the air requirement (C) then the compressor can supply the load. If the compressor is unloaded or shut off, the capacity falls to 0 and the receiver must maintain/supply the load for T minutes. You may need a larger tank to meet these requirements.
Benefits of Properly Sized Tank
- Stable system pressure
- Tank can provide cooling due to the large surface area and condensate can be collected and expelled into an EPA certified Oil/Water Separator
- Remove any pulsations in the system from multiple or different types of compressors (recips)
- Reduce or prevent air compressor "short-cycling" and extend the life of the air compressor and control components
Where Should the Air Receiver Be Located?
An air receiver located before the system Air Dryer is considered a "Wet Tank" and an air receiver located after the Air Dryer is considered a "Dry Tank". There are benefits to using either of these tanks, but it is our recommendation to use BOTH A WET AND A DRY TANK. Air receivers are inexpensive and offer huge benefits, you should take advantage of both.
Remote air receivers near the point of use can also be very beneficial and should be considered in larger systems. Specifically near a particular piece of equipment that consumes large volumes of air in a short periods of time.