Circular Sight Glass 320 – PN 10/16 – DIN 28120

According to DIN 28120

Type 320 circular sight glasses are welded into or onto the wall of a vessel to allow observation or lighting of the container’s interior. The Sight Glass 320 is designed in accordance with the DIN 28120 standard and can be easily used to replace existing fittings that comply with DIN 28120. A sight glass made of highly chemically resistant borosilicate glass DIN 7080 (or similar) is fixed between two high-quality stainless steel flanges and proven quality seals. This sight glass meets all defined operating standards, such as resistance to vacuum and operating pressure up to 16 bar(g).

With the Circular Sight Glass 320, we go beyond the DIN 28120 specifications, offering this model in special dimensions such as DN 250 and above. These diameters, not specified in the standard, are also developed in full compliance with DIN 28120 and DIN 7080 (or similar), ensuring that even in such specific cases, the limits can be applied according to the standard.

The Sight Glass 320 is constructed from high-quality stainless steel 1.4571 (316Ti), highly valued by our customers. The glass material used is industry-proven borosilicate glass 3.3, in accordance with DIN 7080 (or similar). The connection is sealed with flat gaskets adapted to your needs from an extensive range of materials; in addition to the widely used fiber gaskets, we also offer more sophisticated materials such as PTFE (Teflon®), NBR, graphite, and many other brand-name gaskets.

If the maximum operating temperature of 280°C does not meet your requirements, or if the process conditions pose a problem even for the highly resistant borosilicate glass, a mica or FEP protective screen specially adapted for the connection offers additional protection against steam and aggressive chemicals, such as alkalis up to a pH value of 14.

Like other circular sight glasses, 317 and 318, the 320 model can be equipped with SGW or SWII type brushes (with flexible shaft), spraying devices, and lights upon request.

TECHNICAL DATA – SIGHT GLASS 320

Flange Material:Base Flange: 1.4571 (standard)
Cover Flange: 1.4571 (standard)
Other materials on request
Design:In accordance with DIN 28120
Seals:KlingerSil® C4400
PTFE, FKM, NBR, Silicone, EPDM, Graphite
Nominal Size:DN25 to DN300
DN200 to DN300 (similar to DIN 28120)
Temperature / Glass:Up to 280°C with DIN 7080 borosilicate glass
Up to 150°C with DIN 8902 soda-lime glass
Up to 400°C with non-tempered borosilicate glass
Options:SGW cleaning brush in PTFE or silicone
LED lighting for EX and Non-EX zones
SV1 spraying device
O-ring seals (for vacuum applications)
PLEXIGLAS® – impact protection
VA perforated impact protection
FEP sight glass protection (for high pH values)
Mica protection (up to 320°C with DIN 7080 borosilicate glass)
Double glazing (320D)
Special designs on request

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