The main element of the sight glass level indicator is the body. Incorporated into this body are the liquid channel (if necessary the heating channel) and the seating faces for the chambered seals and sight glasses.
Onto the body are mounted, or are already integrated, the valve heads and process connections. Drain or vent are also possible.
The glasses and/or mica discs as well as the seals are fitted, secured and sealed with the aid of U-bolts and covers or pressure frames. Glasses from borosilicate glass in accordance with DIN 7081 are used.
For steam, the glasses can be used up to 243 °C, with mica design to 300 °C. For other media, temperatures up to 300 °C are possible, in special cases up to 374 °C. The use of mica is needed for specific applications.