Kenco Engineering Flat Glass Level Gauge - Manual (Page 3)

Page 3
MAINTENANCE
The following is a step-by-step procedure for maintaining your Kenco Flat Glass Gauges:
A.
Inspection of Glass:
Look at the glass regularly for any signs of clouding or scratching. In new processes, the glass should be inspected
daily until the need fro replacement becomes apparent. This will help establish the routine inspection / maintenance
cycle.
To examine for scratches, shine a very bright concentrated light (e.g. MagLight) at a 45° angle. Anything that
glistens brightly should be inspected closely. Any scratch which catches your fingernail, any star-shaped or
crescent-shaped mark which glistens is cause for replacement. If inner (process side) surface appears cloudy or
roughened and will not respond to cleaning procedures (next section), is an indicator of chemical attack and, if
severe, is cause for replacement.
B.
Cleaning of Glass
Keep glass clean using commercial glass cleaners (e.g. Windex, Bon-Ami). If these don’t seem to work, a dilute
solution of Hydrochloric (muriatic) acid can be used. Observe safety rules when handling these dangerous
chemicals. Cleaning should be done without removing the glass. This may require recirculation of cleaning
materials if the process side of the glass is not accessible. Never use harsh abrasives, wire brushes, metal
scrapers, or other things which could scrape the glass.
C.
Receiving and Storing Glass
Upon receiving replacement glass inserts, inspect containers and glass inserts for shipping damage. Keep glass in
original box until ready for use. If glass is to be inspected, unwrap and re-wrap carefully, avoiding bumping or sliding
polished face across any other object (including table tops).
D.
Disassembly
Prior to any disassembly of the gauge, first be sure that the gauge is relieved of all internal pressure, and that the
gauge is at ambient temperature. Loosen end bolts first, working from opposite ends toward the center.
E.
Reassembly Guidelines
NOTE: See the section on “GAUGE CONSTRUCTION” for the location any parts discussed below.
Kenco gauges use molded borosilicate glass, tempered to increase its bending resistance. This glass has a low
coefficient of expansion and is more resistant to thermal shock than other glasses. Nevertheless, like any glass it is
much stronger in compression than it is in tension. You should be careful not to impose any bending on the glass, or
set up any local stresses. The following points should be observed to insure long life:
•
Check with the Maintenance Supervisor or Engineer for the proper glass to be used in the gauge. Check
box and glass labels or marking against the gauge pressure and temperature ratings.
•
The glass, gaskets, cushions, and bolts should not be reused, even when they appear in perfect condition.
Replace with new parts. Bolts will stretch when re-torqued, thereby weakening them. Glass deforms under
pressure from the chamber and cover. Even though a used glass may look perfect, it is not as reliable as a
new one. Best practice is to always use a new glass.
• The glass should be seated on a flat surface with a suitable gasket on the seating surface to avoid
subjecting the glass to stress concentrations which result from poor loading. It should be clamped in place
with a flat cover plate that is uniformly loaded, as described in the “Reassembly Procedures” below.
CAUTION – While the gauge glass is in operation, the shutoff valves must be fully open. A partially open
valve will the automatic ball checks from seating, which could result in physical injury to
personnel and loss of product.
CAUTION – DO NOT attempt to clean the glass while the gauge is in operation.
CAUTION – Failure to relieve pressure may result in a sudden release of internal pressure, which can cause
physical injury, and/or glass breakage..