DIN 28121 Circular Sight Glass Fitting

DIN 28121 Circular Sight Glass Fitting



Observation and illumination of the interior of enclosed vessels (cauldrons, tanks, silos etc.). Sight glasses consist of round flange mountings to be welded into or onto a vessel, completed by a sight glass plate with appropriate seals.


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Sight glass fittings to DIN 28121 are circular paired retaining flanges sandwiching a sight glass disc, set in two seals and bolted and correctly tightened together at manufacturer’s works to form an integral package. The unit is ready drilled and finished to fit onto flanged nozzles, weld pads etc.; construction and dimensions correspond to DIN 28121. For viewing of internals of pressure vessels, tanks, silos, stirred vessels, separators pipelines etc.

  • Circular flange assembly for bolting straight onto existing flange
  • Complete with fully gasketed glass disc
  • Nominal sizes: DN40 to DN200
  • Viewing Diameter: 48 to 150mm
  • Operating Temperature up to 200°C, higher available on request
  • Operating Pressure up to 25 bar
  • Materials: stainless, carbon steels and specials such as Hastelloy
  • Custom built versions