Round sight glass fitting Type 321A Similar to DIN 28121 for flange mounting on ASME / ANSI flanges

Our round tank sight glasses, known as Type 321A, are threaded onto ASME B16.5 flanges, providing a clear view of tank interiors or enabling illumination. ACI's tank sight glasses Type 321A are designed similarly to DIN 28121 for operating pressures of up to 20 bar.

These sight glasses feature a chemically resistant borosilicate glass DIN 7080, clamped between two high-quality stainless steel flanges, with a PTFE-encased resilient on the media side. The design places the gasket in the force shunt, ensuring that the flange parts lie directly on top of each other, offering the best protection for the glass plate.

The Type 321A is delivered pre-assembled from the factory, ready for direct screwing onto ASME B16.5 flanges without additional effort. In the rare event of glass damage during operation, the entire fitting can be easily replaced.

Our Type 321A tank sight glasses are constructed from high-quality stainless steel 1.4571 (316Ti), a material highly valued by our customers. The glass material used is borosilicate glass 3.3 according to DIN 7080, known for its industry-proven performance. The design of the gasket in the force shunt eliminates the need for on-site gasket adjustments, making retightening of clamping screws unnecessary. The PTFE-encased gasket ensures that the Type 321A is suitable for various applications, including foodstuffs, acids, alkalis, and aggressive chemicals.

In cases where the process conditions pose challenges even for highly resistant borosilicate glass, we offer an FEP or mica protective screen specially adapted to the fitting, providing additional protection against steam and aggressive chemicals, including alkalis up to a pH value of 14.

Similar to our other sight glass fittings, the Type 321A can be optionally equipped with sprayers, SGW type wipers, or lighting solutions to meet your specific requirements.