Processing
Clay and grog are carefully ground, then mixed with water and homogenised.
EUROPEAN FEDERATION OF THE VITRIFIED CLAY PIPE INDUSTRY | EUROPÄISCHE VEREINIGUNG DER STEINZEUGRÖHRENINDUSTRIE | FEDERATION EUROPEENNE DES FABRICANTS DE TUYAUX EN GRES
Consistent high quality is guaranteed by the correct mixture of the natural raw materials clay, grog and water and high-tech manufacturing processes developed over many years. Every single process step is monitored by a sophisticated quality management system.
Clay and grog are carefully ground, then mixed with water and homogenised.
Pipes are formed using vacuum extruders that shorten drying and firing times.
Pipes dry at about 80 °C. Modern production technology like rapid drying allows drying time to be reduced and tolerances to be minimised.
Some manufacturers glaze products, dipping pipes and fittings either before or after drying in a glazing liquid made of clay, lime, dolomite, quartz, metal oxides and water.
Firing (at temperatures of about 1250°C) is the most important process; it is during kiln firing that vitrification – heat fusion – occurs. It is here where absolute perfection is required: products leaving the kiln have to be perfectly accurate.
After firing, socket/spigot pipes are jointed with systems in accordance with EN 295; plain ended pipes may have couplings factory fitted or couplings may be supplied loose.