In some working conditions, the sight glass needs a flashlight to better observe the inner tank conditions. The sight glass with lamp is designed for such a working condition.
Sight glass is also called sight windows or view ports. It is composed of two flanges, bolted together, surrounding a glass disc sealed with gaskets and provides a means of viewing the inside of a process vessel or tank. They are typically used to visually verify stages of a process, inspect process media, and to observe liquid levels.
Common applications include the viewing of internals of pressure vessels, tanks, silos, stirred vessels, separators pipelines etc.