MAXOS®

Safety Sight and Level Gauge Glasses

MAXOS® Level Gauge Glasses reflex and transparent

Bending strength is determined by the surface compressive stress and the inherent resistance of the glass. The inherent resistance is heavily dependent upon the surface quality.

For safety reasons, the stress to the glasses caused by internal forces, thermal stress and vessel pressure have to be totally absorbed by the surface compressive stress so that a tensile stress of the glass surface is prevented.

Application conditions Maximum permissible pressure Maximum permissible
temperature
  bar psi °C °F
Saturated steam or hot water in direct contact with reflex or transparent sight glasses 35 500 243 470
Saturated steam or hot water in contact with transparent sight glasses protected with mica 103 1,500 320 608
Non-corrosive, non-steam service and no technically significant glass attack, with reflex or transparent glasses 280 4,000 38 100
Transparent sight glasses in contact with medias with no technically significant glass attack 345 5,000 38 100
High pressure transparent sight glasses in special gauges 414 6,000 38 100

Temperature

Thermal shock resistance Δ T 230 °C
Max. permissible temperature 300 °C (572 °F)
Protected with mica 320 °C (608 °F)

Surface compressive stress (typical values)

Standard level gauge glasses
≥ 90 N/mm2 13,000 psi
Average 100 N/mm2 14,500 psi
High pressure level gauge glasses
≥ 100 N/mm2 14,500 psi
Average 110 N/mm2 16,000 psi

Parallelism

Standard level gauge glasses
≤ 0.13 mm 0.005 inches
High pressure level gauge glasses
≤ 0.05 mm 0.002 inches

Bending strength (typical values)

Standard level gauge glasses
≥ 150 N/mm2 21,000 psi
Average 170 N/mm2 25,000 psi
High pressure level gauge glasses
≥ 180 N/mm2 26,000 psi
Average 200 N/mm2 29,000 psi

PRODUCT RANGE