Page 130 - 20250602 EEA QM Edition 6.0

Quality Requirements Edition 6.0 European Enamel Association

8.7.8 Packing enamelled plates in baskets for regenerative heat exchangers
8.7.7 Valuation of black specks in the enamelling

The way of packing in the baskets should be that the “notches” of the corrugated and
Definition and cause
undulated plates always must be crossed.
On light coloured direct-on enamellings (white or coloured) black specks can appear.
In these cases, reacting gases convey, during firing, the adhesive layer respectively The tuning of the pressing force for packing shall be done on the required pressing force
a trans- parent layer (being rich in FeTiO3) towards the surface. By conventional
as written down in the specifications for the heat exchangers.
enamellings the ground coat layer then reaches the surface of the cover coat.

The calculation of the pressure on the filled basket is: P = F / A
P = pressure in kg/m
2
F = pressing force in kg
A = pressed area in m
2

The calculation of A = (the one side surface area in m of the lower plate in the basket
2
+ the surface of the upper one) / 2.

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