Maximum Allowable Internal
Gas Rod Load
Ariel gas rod load ratings are
based upon calculated internal gas rod loads. The maximum allowable gas
rod load of a given frame shall not be exceeded at any operating point.
See the Internal Rod Load,
Gas section of “Compressor Application Definitions” for the gas rod
load equations.
Gas rod load is best monitored
for alarm and shutdown with the use of a differential pressure switch
across each cylinder at the flange (cylinder discharge pressure minus
cylinder suction pressure). The performance software and the rod load
charts from the DataBook are available to assist in determining the differential
pressure settings.
If the operating conditions are
to include the relief valve set pressure, the compressor gas rod load
must be maintained within the gas rod load limit, either by not exceeding
the gas rod load limit at relief valve set pressure, or by applying a
shutdown switch on differential pressure across the cylinder. The relief
valve is meant to protect the pressure equipment from exceeding system
pressure ratings. Relief valve set pressures are discussed in the Packager
Standards Section 4.
Caution: The Ariel DataBook lists gas
rod load ratings for both current and inactive frames. Always check the
frame nameplate or contact the Ariel Response Center for the maximum allowable
internal gas rod load when calculating compressor performance for existing
equipment.
Ariel
Corporation Application Manual
28 April 2006