Sapphire glass sight glass plates

Product specifications: Round sight glass plates, longitudinal sight glass plates, sight glass rings / tubes

Material: Sapphire monocrystal

Optical properties as well as further information on the glass can be found in our info data sheet

INFO Data sheet sapphire glass – (133.04 KB)

Sapphire monocrystal sight glasses are required wherever visual inspection of processes in containers must be ensured under extreme pressure, thermal and chemical stress.

Sapphire glass consists of 99.997% Al2O3 and is therefore very suitable for transmission in the UV range. It is characterised by above-average chemical resistance. In addition, it is the best choice for extreme high-temperature applications.

Production and quality checks in the process sequence guarantee the property values of the glasses and the tight dimensional tolerances. With these outstanding properties, these sight glasses are suitable for extreme conditions.

Operating conditions:

Temperature: up to 2000 °C / 3632 °F

Pressure: depending on diameter and thickness

Calculation of the pressure resistance: TOOL - Glass consultant sapphire glass

Technical information:

Coefficient of expansion at 25 °C / 50 °C (77°F / 122°F) :6,6 x 10–6 cm °C-1

Young's modulus: E 4,6 * 10² GNm

Thermal conductivity at 25 °C / 77 °F: 0,08 cal cm-1 s-1 °C-1

Chemical resistance:

Water resistance DIN ISO 719/720: Hydrolysis class 1

Acid resistance DIN 12116: Acid class 1

Alkali resistance DIN 52332: Alkali class 1


Sapphire glass offers very different qualities. These are, due to the cultivation of the sapphire crystals, completely arbitrary and are determined after testing. Synthetic sapphire glass is evaluated to be suitable for the intended application. Either optically, mechanically, etc. A very high quality sapphire galss produces little or no light scattering or grating distortion and is mainly used for the most demanding optical applications.

Lower quality sapphire glasses can have high light scattering or grating distortion and are therefore mainly used for mechanical, structural applications and less demanding optical applications. Nevertheless, for all qualities, sapphire glass is very high quality compared to other materials, such as borosilicate glass.

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