Kenco Engineering ASF Sight Flow Indicator - Manual (Page 3)

Once a glass has been removed from its mounting in process equipment, regardless of
the reason for removal, discard it and substitute a new piece. Used glass may contain
hidden damage. Be sure that the glass is appropriate for the service application.
Check any in-line safety devices for compatibility with temperature and pressure
limitations of the glass. If glass is removed, protective shields to keep cold air, water
or falling objects form damaging the glass must be put back into position. Gaskets
must always be replaced with gaskets of the same material once a unit has been
disassembled.
SERVICE INSTRUCTIONS
A. DISASSEMBLY
The units must be removed from the line and bench disassembled. Remove the heads
by removing the cap screws or nuts on all models. Carefully remove the glass,
gaskets and other hardware. Place everything on a clean work surface.
B. INSPECTION
The glass seating surfaces in the body and in the retainer should be carefully cleaned
and checked to insure that there are no pieces of old gasket material, chips, residue,
dirt or other material on the surfaces. Any foreign particles left on the surface could
cause high local stresses in the glass, possibly resulting in its failure.
CRACKED GLASS CAN BE CAUSED BY THE FOLLOWING:
1. Pressure in excess of the glass rating
2. High local stresses, which can be due to uneven bolt torquing or foreign particles
on the glass seating surface.
3. Thermal shock of the glass.
It is important to determine the cause of the glass crack. Simply putting in a new
glass will not alleviate the cause for placement. Consultation with the manufacturer
may greatly extend the service life and reliability of the units in service. Check your
operating conditions against the ratings on the unit’s nameplate or accompanying
literature. If there are any questions about the ratings of the unit for the service
intended, do not proceed without verifying the unit applicability with the maintenance
supervisor or engineer.
C. GENERAL REASSEMBLY INSTRUCTIONS
Always reassemble sight flow indicators using new glass and gaskets. The potential
of hidden damage makes used glass and gaskets an extreme safety risk. Check the
new glass to ensure that there are no bumps, chips, scratches or other imperfections.
Be certain that the gaskets are clean.
The glass and gaskets should be verified as correct for the application. Generally, a
direct replacement of the glass and gaskets that were in the unit before disassembly
should be correct, but you should check with the maintenance supervisor to avoid a
costly mistake.