Air receivers are tanks used for compressed air
storage and are recommended to be in all compressed air systems.
Using air receivers of unsound or questionable construction can be
very dangerous. Therefore, the American Society of Mechanical
Engineers (ASME) has developed a code regarding the construction of
unfired pressure vessels, which has been incorporated into many
federal, state, and local laws. This particular code is ASME Code
Section VIII Division 1. Air receivers should always meet or exceed
this code in addition to any other state, municipal, or insurance
codes that may apply.
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questions. Learn more with this helpful article about How to Size an Air Receiver
Tank.
The ASME also approves the receiver
accessories. They are equipped with a safety valve, which is set at
a pressure lower than the working pressure for which the air
receiver was stamped and at a higher pressure than the operating
pressure, to safeguard against excessive pressure. In addition,
receivers have a drain valve to eliminate accumulated moisture.
They also have pressure gauges, handholes or manholes, and a base
for vertical air receivers. Standard receivers are designed for
horizontal or vertical mounting.
Air receivers serve several
important purposes:
⢠Decrease wear and tear on the
compression module, capacity control system and motor by reducing
excessive compressor cycling.
⢠Eliminate pulsations from the discharge line.
⢠Separate some of the moisture, oil and solid particles
that might be present from the air as it comes from
the compressor or that may be carried over from the
aftercooler.
⢠Help reduce dew point and temperature spikes that follow
regeneration.
⢠Offer additional storage capacity made to compensate for
surges in compressed air usage.
⢠Contribute to reduced energy costs by minimizing electric
demand charges associated with excessive
starting of the compressor motor.
The benefit of extra storage capacity
alone outweighs the additional cost of this component.
Wet vs. Dry
Receiver:
There are wet air receivers (supply)
and dry air receivers (demand). (fig. AR1-3)

Wet Receivers: Wet
receivers provide additional storage capacity and reduce moisture.
The large surface area of the air receiver acts as a free cooler,
which is what removes the moisture. Because the moisture is being
reduced at this point in the system, the load on filters and dryers
will be reduced. The term "wet receiver" refers to the storage
vessel or tank placed immediately after the
compressor. This device helps with contaminant removal, pressure
stabilization and
pulsation reduction.
Dry Receivers: When
sudden large air demands occur, dry air receivers should have
adequate capacity to minimize a drop in system air pressure. If
these pressure drops were not minimized here, the performance of
air dryers and filters would be reduced because they would no
longer be operating within their original design parameters.The
term "dry receiver" refers to the receiver placed after the air
dryer and other air
preparation equipment.
Air receiver
sizing:
The size of the air receiver is
dependent upon air usage and the compressor style. The general rule
to size a air receiver is:
⢠Receiver Size = Compressor ACFM * 1 Gallon/ACFM
⢠For a 200 ACFMCompressor = 200 Gallons
⢠With a Conversion Factor of 7.48 Gallons/Cubic Ft. = 27 Cubic
Ft.
Installation
Recommendations:
Wet receivers should be installed downstream of the moisture
separator and before other purification equipment. Dry receivers
are installed after purification equipment. All air receivers
should be on blocks or some other small foundation to keep them dry
and rust-free. There also should be enough space left around the
receiver to allow for easy draining.
Exercise care when installing air
receivers outdoors because any condensed moisture may freeze and
interfere with the operation of drain valves, pressure gauges and
safety valves. Never install a valve between the air receiver and
the safety valve. The exhaust from the safety valves should be
directed away from personnel and in a way that the thrust will
tighten threaded pipe fittings if it lifts and blows, as opposed to
unthreading them.
Pressure gauges should be of good
quality and large enough to read while standing on the floor.
Install an isolation valve between the gauge and the tank so that
the gauge can be removed and replaced or recalibrated every six
months without depressurizing the tank. It is essential that air
receivers have an automatic trap/drainage system. Also, the
receiver needs to be bolted or clamped to the floor or base on
which it is mounted in case of a line fracture.
Maintenance
Requirements
Moisture should be drained from the
receiver regularly, especially in cold weather to avoid problematic
accumulation. If you need to add any braces, struts, base supports
or nozzles to an air receiver, use an ASME Coded weld shop for any
welding or repairs. Many companies have a policy to annually
hydrotest the air receiver's integrity. Besides hydrotesting, older
air receivers should be checked periodically with an ultrasonic
thickness gauge or meter. Corrosion effects can be determined by
comparing readings of head and shell to the nameplate.
Browse our selection of Air Receiver
Tanks or call us toll-free: 866-650-1937 if you have any
questions.