Tubular Sight Glass (Gauge Glasses):
Diameter and wall thickness of sight glass tubing are expressed in millimeters (generally length is, too). The tradition of describing some gauge glasses in inch dimensions still remains, but has become less and less common.
The common types are:
SG-901 sight glass (tubular), DURAN®, fire polished ends, annealed.
These are available in a range of sizes but the most common which replace the old inch sizes are:
12 x 2.2 (replacing 1/2”)
16 x 2.5 (replacing 5/8”)
19 x 2.5 (replacing 3/4”)
SG-901 – 16 OD* x 2.5mm wall, Max Pressure**: 25 Bar
SG-901 – 19 OD* x 2.5mm wall, Max Pressure**: 20 Bar
**Assuming no physical damage, no applied mechanical stress
SG-900 sight glass (tubular), DURAN®, parallel ground ends (for compression between flanges).
Again available in a wide range of diameters. Typically, these are relatively short for their diameter and are made from heavy-wall tubing. For instance, SG-900, 80 X 5.0 X 120 which describes a parallel-ground sight glass 80mm in diameter with a 5mm wall and 120mm overall length.
Disc Sight Glasses:
Specified by diameter and thickness:
SD-920 sight glass disc, soda float glass, annealed
SD-921 sight glass disc, soda float glass, heat strengthened
SD-922 sight glass disc, SCHOTT Borofloat 33, annealed
SD-923 sight glass disc, SCHOTT Borofloat 33, heat strengthened
We can also supply discs manufactured from other vitreous materials such as Schott Robax (glass ceramic) and clear fused quartz (silica).
Engineers Deserve to Get SCHOTT…And We’ll Make Sure They Do!
SCHOTT’s acclaimed DURAN® glass tubing is at the heart of our tubular gauge glasses. Its high level of chemical resistance is matched only by its high thermal impact resistance. High homogeneity and strong transparency (as well as tight dimensional tolerances) ensure accurate, reliable, and long-lasting performance as a gauge glass.
Tough, light and versatile, BOROFLOAT® is coveted by technology companies and scientific institutes for its superb technical capabilities. Excellent transparency and thermal and chemical resistance make it ideal for automotive applications, digital projection, inspection windows, and much more.