Metaglas Safety Sight Glass

METAGLAS© Improved Safety, Constructive Solutions and Simplified Fitting with Metal Fused Sight Glasses

Introduction • Conventional sight glasses are sensitive to stress, bending and impact and when subject to mechanical overload they may catastrophically fail without warning. This can cause a relatively minor expense and inconvenience if it happens during installation but a major cost and safety implication if it occurs when plant is fully operational.

  • METAGLAS® eliminates this mode of sight glass failure, helping to improve safety and avoid the expense and inconvenience of unscheduled plant shut downs. These advantages are due to the unique "glass fused to metal" fabrication of METAGLAS® which gives it unmatched strength and integrity.
  • METAGLAS® is made by melting circular glass inside a metal frame. This results in the fusion of glass and metal. Upon cooling, the glass solidifies and the difference in the linear coefficient of thermal expansion between glass and metal then produces forces that create a uniform compressive stress throughout the glass.
  • This high degree of mechanically induced compressive stress makes METAGLAS® the strongest and most secure sight glass for sight window or visual flow indicator application.

Special Features • Reliability against total failure - due to the mechanically prestressed glass

  • Unsurpassed resistance to pressure, impact and temperature
  • Simple, stress free installation - resistant to bending, overtightening and impact
  • Reusable - Metaglas can be cleaned and reused in the same or other applications,conventional sightglasses cannot.

Applications • METAGLAS® can replace conventional glass in many applications including circular flange assemblies for welding into vessels, weld neck & nozzle flanges and sight flow indicators.

  • In addition, Metaglas cover flanges can be mounted onto flat face base flanges, these are available for all international flange connections including ANSI & BS. Existing installations can therefore be easly retrofitted to improve safety and extend plant life. The unique pro­perties of METAGLAS® also make it ideal for use with sanitary mounting systems.
  • METACLAMP®s are available as sight glass caps for sanitary clamp and In-line systems and sight glasses and Luminaire adaptors for sterile flush mount designs such as the
  • NA-Connect system and Triclamp fittings.
  • METAGLAS® has been subjected to the most rigorous tests by specific testing facilities in the chemical industry and has subsequently been integrated into their works standards.

Specifications • Pressure Equipment Directive 2014/68/EU

  • module H/H1 (DIN/EN/ISO9001)
  • Materials to VdTUV specifications & DIN/EN standards
  • Sight glass fused to metal to DIN 7079
  • AD Standards W0/TRD 100
  • 3-A Standard for food processing

Tech Data • Materials: Duplex stainless steel 1.4462

  • Carbon steel 1.0570, Hastelloy and others
  • Operating Temp.: -30°C to +280°C (300°C)
  • Operating Pressure: 64 bar (TUV)
  • 1000 bar, depending on material and design

METAGLAS© versus Toughened Glass

The structure of toughened glass is such that any surface damage or stress caused by uneven forces can lead to catastrophic failure. The structure of Metaglas is such that surface damage is limited to local areas and does not affect the overall strength of the glass. Local pitting or cracking may cracking may obscure the view but the glass remains leak tight and secure. Likewise, uneven stresses do not cause Metaglas to fail.

Tempered GlassMETAGLAS®
Surface Damage Damage to the tempered surface can cause unexpected catastrophic failure Scratches or any other surface dama­ge do not affect the safety or life of METAGLAS®.
Re-useResidual stress is created during bolting. Re-bolting causes excessive residual stress which can lead to failure.
Glass cannot be re-used.
Repeated re-bolting does not affect Metaglas strength and integrity.
ImpactImpact (mechanical shock) causes catast¬rophic failure causing the glass to shatter into a multitude of small fragments. METAGLAS® has an extremely high
resistance to impact. Very high impact may cause local pitting of the glass but does not affect its function or its integrity.
Bending MomentTempered glass is very sensitive to uneven torquing of sight port bolts. The glass surfaces must be entirely flat and smooth (within 0.07 mm) to avoid uneven torquing. Extremely high tolerance to uneven torquing.
Uneven surfaces do not therefore result in glass damage.
InstallationUneven or over torquing results in the glass cracking. METAGLAS® cannot be overtorqued since torquing is metal on metal.
Reaching the limits of uneven torquing cracks will appear but the METAGLAS® will remain leak tight.
CorrosionCorrosion, particulary through the glass toughened surface, results in significant weakening which can lead to catastrophic failure. METAGLAS® will remain leak tight to a high level of corrosion.
CleaningGlass must be replaced unless it can be cleaned place (CIP). METAGLAS® can last indefinitely regardless of how many times you remove, clean and replace it.