Introduction to boiler enameling technology
Hot water tanks, which are typically used for
(solar) boilers, may be manufactured from either stainless steel, copper or
mild steel. The selection of the appropriate substrate depends on many
factors, such as the annual production volume, the average dimensions of the
tanks, expected water quality, desired product life and raw material cost.
Due to the ongoing price increases of stainless
steel & copper, there is nowadays a worldwide trend towards
manufacturing hot water tanks from mild steel. HWT's made of mild steel need
to be coated internally, either with zinc, powder coating, nylon or enamel to
protect it against corrosion.
According to a publication by the CISP, in which the
various corrosion protection methods were compared, porcelain enamel provide the best protection
(read longest life) against corrosion by
boiling water. Porcelain enamel is a glass-alike coating, which needs to be
applied on a clean substrate surface and then fired inside a high temperature
furnace.
In the past the porcelain enamel layer was typically
applied in a wet form, either by flow coating or air spraying. However,
thanks to technological developments it is also possible to apply the enamel
by means of electrostatic dry spraying, which application method has many
operational benefits,
such as :
-
Shorter lead time and less process steps, thanks to elimination of enamel preparation and drying.
-
Almost 100 % material utilization, thanks to automatic recovery of any
over-spray powders.
-
Environmental friendly, because there are no air, waste water or solid waste emissions.
Simple systems with high level of automation helps to reduce your labor
cost and guarantee a good and constant finishing quality.
Powder enamel systems require less factory space then all equipment for
wet
enamel process.
To achieve maximum protection from your enamel
coating, it is important that the tank design and steel grade are suitable for
the selected enameling process and comply with the international standards, such
as DIN 4753-3.
A modern enameling plant has only three process
stages. (shotblasting, application, firing) Depending upon the local labour cost
& hourly production capacity, the various machines may be integrated by means of
one or more overhead conveyor systems.
The size and
layout
of a boiler enameling plant
depends mainly upon the selected enameling process, the desired hourly
production capacity, the maximum tank dimensions and the level of integration
between the various machines.
Thanks to
many years of experience with
porcelain enameling projects worldwide, Ditmer Trading & Consulting BV may provide you
all necessary process & equipment
know-how and practical support during all stages of your boiler enameling plant
project. Please
contact us in order to discuss any requirements
and/or questions you may have.Click
here for a summary of our services.