What are union sight glass and its applications

Mostly simple in design, rudimentary sight glasses of the past consisted of a glass tube that was connected to an important part of your system, such as a gas tank or outlet. Modern industrial glasses are made with a glass disc that is held firmly by bolts and gaskets between two metal frames, to maintain the standards of sanitary fittings. The union sight glass that’s used is typically soda-lime glass or borosilicate glass, while SS is the go-to choice for the metal due to its superior strength and abrasion resistance, even with 304 Stainless Steel.