Circular sight glass fitting type 321 DIN 28121 PN 10/25

Product information

Our round vessel sight glasses type 321 are screwed onto flanges according to DIN EN 1092-1 to allow for observation or illumination of the interior of the vessel. ACI vessel sight glasses of type 321 are designed according to DIN 28121 for operating pressures up to 10 or 25 barg. Here, a sight glass made of chemically highly resistant borosilicate glass DIN 7080 is clamped between two high-quality stainless steel flanges and a media-side PTFE-coated corrugated ring gasket. Since this gasket is situated in the force shunt, the flange parts of the sight glass are directly aligned with each other, thus protecting the glass plate as much as possible.

The type 321 is delivered pre-assembled from the factory and can be mounted directly onto a flange according to DIN EN 1092-1 without additional effort. Should the unlikely event occur that the glass is damaged during operation, the entire fitting can be replaced with little effort.

Our vessel sight glasses of type 321 are made from high-quality stainless steels 1.4571 (316Ti) or 1.4404 (316L). The glass material used is the industry-proven MAXSO® borosilicate glass according to DIN 7080. The sealing in the force shunt prevents settling of the gaskets, making it unnecessary to retighten the tension screws on site. The PTFE-coated gasket makes the vessel sight glass type 321 suitable for food, acids, alkalis, and most aggressive chemicals.

If the borosilicate glass DIN 7080 does not meet your requirements or the process conditions themselves pose a problem for the highly resistant borosilicate glass, a custom-made mica protection plate for the fitting provides additional protection against temperature and steam. FEP or Halar® coatings additionally protect the borosilicate glass from aggressive chemicals or alkalis.

As with other sight glass fittings, type 321 can be equipped upon request with a sight glass wiper type SGW, spray devices SVII, or lights.