BS EN ISO 28763 pdf download Vitreous and porcelain enamels — Regenerative, enamelled and packed panels for air-gas and gas-gas heat exchangers — Specifications
lf required by the enameller, the thermal-shock resistance shall be determined in accordance withAnnex A at a test temperature of 350 C on at least three test specimens prepared in accordancewith ISo 28764.
After testing five times at the test temperature, the test specimens shall show no damage.5.7Adherence
The adherence shall be determined in accordance with EN 10209:2013,Annex C, using test specimenswith a known pickling speed(see 4.5) prepared in accordance with ISO 28764.
The method of pre-treatment, application and firing of the enamel shall be described.
6Characteristics of the enamel coating
Test specimens for the determination of adherence shall be prepared in accordance with ISO 28764and shall be pre-treated and enamelled under the same conditions as for the production of the heatexchanger panels.
When determined in accordance with EN 10209:2013,Annex C, the adherence of the enamel shall be atleast level 2.
Tests shall be carried out on every pre-treated batch of panels.6.2Thickness
The thickness shall be determined in accordance with ISo 2178.Adjustment of the measurementequipment shall be carried out on the profile concerned. Select a pair of panels,one corrugated andone undulated, and carry out measurements from point A to point l (see Figure 1) on the front andreverse faces of each panel.The measurement points shall be situated at least 50 mm from the edge.The measurement points on the corrugated panel shall be as indicated by numbers 1 and 2, and on theundulated panel as indicated by 3.This will result in 54 measurements from each pair of panels tested,36 from the corrugated panel and 18 from the undulated panel.
The mean of the 54 measurements shall be 150 um ± 30 um, unless a different mean is agreed betweencustomer and supplier at the time of ordering.
Along the area bordering the edges of the panels, the total thickness may measure up to 600 um (i.e.two faces of 300 um) plus the thickness of the substrate. If a different mean has been agreed betweencustomer and supplier, the total enamel thickness along the area bordering the edge of the panel mayvary, but should preferably be kept to a minimum to avoid chipping and spalling, etc.
With the exception of edges and suspension holes, the application thickness beside the measurementpoint (such as on both sides of the notches of the corrugation) shall nowhere fall below 80 um.
Measurements other than those at the points indicated shall be carried out on cross sectionsusing microscopy.
The test shall be carried out on a 2 h cycle.