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DEAERATORS

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UFC 3-430-07
24 July 2003
including Change 1, Jan 2004 and Change 2, March 2005
for vessel configurations other than spherical or cylindrical must be approved by the
inspector. The lines and points of measurement will be identical at each inspection.
The activity will maintain measurement records. The vessel will not be derated nor
certified if the measured thickness is less than that prescribed by the standard by which
it was constructed, for example, ASME Section VIII, Division I, ASME Section VIII,
Division 2, or Military Specification MIL-F-22606C, Flask Compressed Gas and End
Plugs for Air, Oxygen, and Nitrogen (SHIPS).
5-4.3
Examination of High Stress Areas. For hyperbaric Facility Support
Pressure Vessels a liquid dye penetrant of magnetic particle examination or other
methods authorized by the Hyperbaric Facility Pressure Vessel Inspection and System
Certification Board must be performed on all areas of high stress concentration such as
nozzles, welds, plugs, threads, etc. before each strength test. The purpose of the test is
to identify any defects that have occurred as a result of high or cyclic stresses.
5-4.4
Variations. Address requests for variations in the inspection and testing
procedures for MILSPEC pressure vessels to the NAVFACENGCOM Boiler Inspection
Certification Board with a copy to the respective (East or West) NAVFAC Senior Boiler
Inspector. If the vessel is used for Hyperbaric Facility Support, address variations to the
Hyperbaric Facility Pressure Vessel Inspection and System Certification Board, located
at Naval Facilities Engineering Service Center, East Coast Detachment, with a copy to
the respective NAVFAC Senior Boiler Inspector. Appendix B depicts the relative
position of the Boiler Inspection Certification Board in the NAVFACENGCOM boiler and
pressure vessel inspection quality assurance organization.
5-5
DEAERATORS. The purpose of a deaerating heater (deaerator) is to
remove non-condensable gases and dissolved oxygen from the feedwater. A properly
operating deaerator will have no more than 10 ppb (parts per billion) O2 in the outlet
water. Deaerators are subject to thermal cycling and corrosion. Proper operation of
deaerators is extremely important because of their critical function in protecting the
boiler system from corrosion. Catastrophic failure of deaerators is usually attributable to
cracks forming longitudinally and transversely to the heat affected zones of the welds.
Deaerators are potentially a great danger because of their location at the top of the
heating or power plant. To ensure deaerators provide safe reliable service, they require
periodic visual inspections of their internal and external surfaces. If visual inspection
reveals cracking, then a company specializing in deaerator inspection must perform an
ultrasonic examination of the entire vessel and wet fluorescent magnetic particle
examinations of the heat affected zones of the welds, prior to certification, to determine
if continued operation of the vessel is safe. Subject repairs to post-weld heat treatment
and hydrostatic testing prior to certification.
5-6
LIQUID PETROLEUM GAS (LPG) TANKS. Non-mandatory guidelines
may be found in the National Board Inspection Code, Appendix H, "Recommended
Guide for the Inspection of Pressure Vessels in LP Gas Service."
5-6.1
External Inspection. Examine LPG (propane, butane, etc.) tanks in
accordance with paragraph 5-2. Record areas of wear, corrosion, abuse, and/or
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