Borosilicate Windows

A selection of optical windows made from borosilicate glass. Borosilicate windows are discs with flats polished to optical finish, sides are ground and lapped, edges are chamfered.

Borosilicate glass is an amorphous material with a low coefficient of thermal expansion, and high resistance to thermal shock although not as high as quartz. Borosilicate glass has excellent clarity for transmitting visible light and near-IR wavelengths.

Borosilicate windows are available in standard nominal DN sizes and thicknesses for nominal pressures PN.

Papenmeier - F. H. / Lumiglas

Lumiglas Sight Glass Discs, Borosilicate

Toughened borosilicate round windows. Edges are chamfered, cylindrical surface is ground and polished. Flat faces have optical finish 40-60 S-D. This window is designed to fit Lumiglas sight glass fittings meeting DIN 28120 with weld-on pads, and also DIN 11851 sight glasses with a screwed on cover flange.

For safety compliance in accordance with DIN 7080 the window must be replaced every time a sight glass assembly is disassembled during scheduled or unplanned maintenance. Once the sight glass disc is removed it should be discarded and not reused, especially on vessels under pressure or vacuum. The glass and the gaskets should be replaced during every time the assembly is taken apart.

Maximum operating pressure can be achieved only when the window is properly installed and tightened with the torque setting and criss-cross tightening pattern recommended for the sight glass assembly. Max operating temperature is 280 degrees C, no lower temperature limit. The window provides distortion-free viewing inside process chambers, mixers, pipelines, silos, food processing vessels. Not recommended for prolonged use with demineralized water.

Nominal SizeWindow Dia.ThicknessMfg. P/N.Encole P/N.Price
ISO-225250.00 mm30.00 mmNot Available317A1025$571.00each
ISO-225250.00 mm25.00 mmNot Available317A1024$578.00each
ISO-175200.00 mm30.00 mmNot Available317A1023$524.00each
ISO-175200.00 mm25.00 mmNot Available317A1022$510.00each
ISO-175200.00 mm20.00 mmNot Available317A1021$492.00each
ISO-150175.00 mm25.00 mmNot Available317A1020$479.00each
ISO-150175.00 mm20.00 mmNot Available317A1019$425.00each
ISO-150166.00 mm15.00 mmNot Available317A1018$354.00each
ISO-125150.00 mm25.00 mmNot Available317A1017$320.00each
ISO-125125.00 mm20.00 mmNot Available317A1016$318.00each
ISO-125142.00 mm15.00 mmNot Available317A1015$183.00each
Load more
Borosilicate comes in a variety of shapes and is traded under brand names such as Pyrex from Corning, Schott N-BK7, Schott BOROFLOAT(R), Schott Suprax 8488, Schott D263. Borofloat and Suprax are commonly used in fused sight glasses. These borosilicate glass materials have different compositions of SiO2, B2O3, Na2O and Al2O3. For sight glass applications the windows are thermally toughened meeting the DIN 7080 Standard for pressure resistant circular sight glasses.
Loading