METAGLAS® Type 176 – Circular Metal-Fused Sight Glass (Form A)
The METAGLAS® Type 176 is a circular, metal-fused sight glass Form A
with a flat sealing surface, designed specifically for weld-neck flanges
according to ANSI B 16.5. It provides a reliable, high-strength viewing window for process systems
operating under pressure and temperature extremes.
This unit serves as a replacement sight glass armature similar to DIN 28121, offering
compatibility with standard ANSI flange assemblies while maintaining superior sealing integrity through
the METAGLAS® glass-to-metal fusion process.
Design & Construction
Type: Circular metal-fused sight glass – Form A, flat sealing surface
Standard: ANSI B 16.5 – fitting dimensions for weld-neck flanges
Compatibility: Replaces sight glass armatures per DIN 28121 geometry
Seal Type: Glass permanently fused to metal ring – no gasket required
Performance: High pressure and thermal shock resistance via mechanical pre-stress
Applications
Process vessels and reactors with ANSI B 16.5 flanged connections
Chemical and petrochemical plant installations
Power generation and steam systems
Industrial equipment requiring direct level or flow observation
Replacement of legacy DIN 28121 sight glass units with modern METAGLAS® design
Key Advantages:
Complies with ANSI B 16.5 flange dimensions
Mechanically prestressed for exceptional pressure and thermal performance
Fully leak-tight metal-glass construction – no separate gasket required
Direct retrofit for DIN 28121 sight glass armatures
Maintenance-free operation and extended service life
John Moncrieff Ltd supplies certified
METAGLAS® Type 176 assemblies for ANSI and DIN-compatible process systems —
engineered for mechanical integrity, pressure safety, and long-term operational reliability.
