Circular flange assembly ready for bolting straight onto weld pad/nozzle flange Glass discs separated by spacer ring and independet seals If damage occurs to one disc, the other maintains service under full operating conditions. Nominal sizes: DN 50 to DN 200 Viewing Diameter: 50 to 175 mm Operating Temperature: 280°C with Borosilicate Glass to DIN 7080; 150°C with Soda Lime Glass DIN 8902 Materials: stainless, carbon steels and specials Custom built versions, e.g. with built in heating