Vessel sight glass Type 321A

monitoringfor hygienic applicationsfor chemicals

Type 321A circular sight glass fitting for ASME/ANSI flange mounting, designed to allow observation or illumination of container interiors. Constructed for operating pressures up to 20 barg and heat-resistant up to 200 °C.

Construction and materials
The sight glass is clamped between two high-quality stainless steel flanges with a media-side PTFE-coated encased corrugated ring gasket in a force-shunt arrangement so that the flange parts lie directly on top of each other to protect the glass plate. The sight glass uses MAXOS® borosilicate glass (DIN 7080). Standard materials are stainless steels 1.4571 (316Ti) or 1.4404 (316L). The type 321A is delivered pre-assembled and can be screwed directly onto an ASME B16.5 flange; the complete fitting can be replaced easily if the glass is damaged.

Key components

• Cover flange
• Glass cushion
• Sight glass (MAXOS® borosilicate glass DIN 7080)
• PTFE-coated encased corrugated ring gasket (media-side)
• Base flange
• Screws / bolts

Options and accessories

• Wiper SGW with PTFE or silicone wiper blade
• LED lights for Ex and non-Ex areas
• Spraying device SVII / SV2 for cleaning
• FEP or Halar® coating for additional chemical protection
• Mica protection disc for temperature/steam protection
• Custom constructions and custom-made designs available

Application notes / features

• Nominal sizes available: 2" – 8" (NPS)
• Suitable for liquid and gaseous media
• Designed for flange mounting according to ASME B16.5 (execution similar to DIN 28121)
• PTFE-coated gasket makes the product suitable for food applications, acids, alkalis and most aggressive chemicals
• Delivered pre-assembled for direct installation on ANSI/ASME flanges

Technical specifications

• Model / type: Type 321A
• Pressure rating: up to max. 20 barg (Pressure rating class available: 150 lbs)
• Temperature (available options): 80 °C, 130 °C, 150 °C, 175 °C, 180 °C, 200 °C
• Materials: stainless steel 1.4571 (316Ti) or 1.4404 (316L)
• Glass material: MAXOS® borosilicate glass (DIN 7080)
• Gasket: PTFE-coated encased corrugated ring gasket (force-shunt sealing)
• Optional coatings/protection: FEP or Halar® coating; mica protection disc
• Nominal sizes (NPS) and corresponding inner diameter Di [mm]: 2" = 65 mm, 3" = 80 mm, 4" = 100 mm, 5" = 125 mm, 6" = 125 mm, 8" = 150 mm
• Height H [mm] per NPS: 2" = 41 mm, 3" = 50 mm, 4" = 59 mm, 5" = 66 mm, 6" = 66 mm, 8" = 66 mm
• Weights [kg] per NPS: 2" = 3.8 kg, 3" = 8 kg, 4" = 13.5 kg, 5" = 17.4 kg, 6" = 23 kg, 8" = 36.7 kg
• Execution: similar to DIN 28121 but adapted for flange connection according to ANSI/ASME