METAGLAS® Type 81 – Metal-Fused Sight Glass for Pipe Coupling (DIN 11851)
The METAGLAS® Type 81 sight glass is a metal-fused, tapered design engineered for
pipe couplings in accordance with DIN 11851. It offers a hygienic, pressure-resistant viewing solution ideal for
food, beverage, pharmaceutical, and chemical processing lines where both optical clarity and mechanical strength are critical.
Its tapered profile ensures seamless installation into standard nozzles and cover nuts, providing
a secure, leak-proof seal and rapid assembly with existing DIN fittings. The precision fusion of glass and metal creates a
permanent mechanical pre-stress, delivering exceptional thermal and pressure performance in sanitary conditions.
Design & Construction
Type: Metal-fused sight glass, tapered version
Standard: DIN 11851 – suitable for normal nozzles and cover nuts
Mounting: Fits hygienic pipe couplings and standard screw connections
Glass-to-Metal Bond: Permanent fusion for high strength and leak-tight performance
Pressure / Temperature Capability: Dependent on nominal size and material specification (available on request)
Applications
Dairy and beverage production lines
Pharmaceutical and biotechnology systems
Cosmetic and sanitary process installations
Chemical and food-processing pipelines
Hygienic inspection and observation ports
Key Advantages:
Tapered design allows easy integration with standard DIN nozzles and couplings
Exceptional mechanical strength and thermal stability
Metal-glass fusion eliminates risk of seal failure or gasket creep
Compact, hygienic, and maintenance-free design
Ideal for sanitary and clean-in-place (CIP) applications
John Moncrieff Ltd supplies certified METAGLAS® Type 81 sight glass assemblies
for hygienic and industrial process environments — precision-engineered for performance, reliability,
and compliance with DIN and PED standards.
