Collection: Flange Sight Glass

Factory-direct flange sight glasses — circular borosilicate glass observation windows mounted between flanges for direct visual monitoring of fluids, gases, and process conditions in tanks, reactors, and pipelines. Available in low-pressure and high-pressure variants. Custom diameters and OEM orders welcome.

Low-Pressure vs. High-Pressure Flange Sight Glass

Key Properties

• Material: Borosilicate glass — high thermal and chemical resistance
• Max. operating temperature: Up to 300°C
• Chemical resistance: Resistant to most acids, alkalis, solvents, and process fluids
• 360° observation — full circular window for unobstructed process visibility
• Pressure tested before shipment on all orders
• Custom diameters available from 25mm to 300mm+

Manufacturing Standards

• DIN 28120
• HG 21619
• JC/T 891
• Custom flange dimensions and standards available on request

Typical Applications

• Chemical and petrochemical reactors
• Pharmaceutical process vessels and autoclaves
• Food and beverage mixing and fermentation tanks
• Oil and gas separators and pipelines
• Water treatment and desalination systems
• Industrial boilers and heat exchangers

Installation Notes

Flange sight glasses are installed between two mating flanges using appropriate gaskets (PTFE, silicone, or fluororubber depending on media and temperature). Proper torque and gasket selection are critical for leak-free performance. View compatible gaskets →

Need a custom diameter, thickness, or flange standard? Contact us for a quote within 24 hours →