Chapter 3 — Waterside Care and Requirements
3-12 Part No. 750-184
F. WASHING OUT
1. HOT WATER BOILER
In theory, a hot water system and boiler that has been initially
cleaned, filled with raw water (and water treated), and with no
make-up water added, will require no further cleaning or treatment.
However, since the system (new or old) can allow entrance of air
and unnoticed or undetected leakage of water, introductions of raw
water make-up or air may lead to pitting, corrosion and formation
of sludge, sediment, scale, etc., on the pressure vessel waterside.
If the operator is absolutely certain that the system is tight, then an
annual waterside inspection may be sufficient. However, if there is
any doubt, the pressure vessel waterside should be inspected no
later than three months after initially placing the boiler into
operation, and periodically thereafter as indicated by conditions
observed during inspections.
2. STEAM BOILER
No later than three months after initially placing the boiler into
operation and starting service, and thereafter as conditions warrant,
the pressure vessel should be drained after being properly cooled to
near ambient temperature. Handhole covers should be removed and
waterside surfaces should be inspected for corrosion, pitting, or
formation of deposits.
Flushing of Pressure Vessel Interior
Upon completion of the inspection, the pressure vessel interior
should be flushed out, as required, with a high pressure hose. If
deposits are not fully removed by flushing, a consultation may be
required with your local Cleaver-Brooks authorized representative.
In extreme cases, it may be necessary to resort to acid cleaning.
Professional advice is recommended if acid cleaning is required.
The inspections will indicate the effectiveness of the feedwater
treatment. The effectiveness of treatment, the water conditions, and
the amount of fresh water make-up required are all factors to be
considered in establishing frequency of future pressure vessel
washouts. Contact your local Cleaver-brooks authorized
representative for more information.
G. BLOWDOWN STEAM BOILER
Boiler water blowdown is the removal of some of the concentrated
water from the pressure vessel and its replacement with feedwater
so that the lowering of the concentration of solids in the boiler water
occurs.
Solids are brought in by the feedwater even though the water is
treated prior to use through external processes that are designed to
remove unwanted substances which contribute to scale and deposit
formations. However, none of the processes can remove all
To Next Page
Loading...