People Also Ask
A sight glass can come in a variety of materials, but the window is typically made from thick borosilicate glass. This type of glass is very clear, with phenomenal light transmission and thermal properties. This glass works in conditions of up to 500°F. Some manufacturers use soda lime glass, for less critical uses.
The discovery and commercialization of borosilicate glasses is widely credited to Michael Faraday and Otto Schott, respectively. Since their inception in the nineteenth century, these materials have been exploited for their thermal properties and chemical durability (Duran® and Pyrex®).
The advantages of borosilicate glass include its durability, chemical resistance, and thermal stability, while the limitations and disadvantages include its brittleness and higher cost compared to other types of glass.
The main difference between the two lies in their application: gauge glasses are used to measure the level of a liquid in a vessel or tank, while sight glasses are used to visually inspect what’s happening inside a vessel or pipe.
The reflective glass level indicator uses a prismatic slot as a device to reflect light if there is liquid in the chamber. While the transparent level indicator simply sees the actual level of the liquid through the smooth glass.
Often referred to as viewing glasses, they offer you a way to see the levels of liquids or gases that are traveling through a critical point of your design, monitor pressure changes, and virtually anything else that sight glass windows could allow you to do.
The most common cause for sight window failures is chemical corrosion, which has undoubtedly ruined more sight glasses than all other mechanisms of failure combined. Chemical corrosion is nothing more than undesired chemical reaction, and will happen to any material under the right chemical environment. Thus, the only way of preventing chemical corrosion is to understand the chemical interactions between the process environment and all wetted components of the sight window.
The main types of sight glasses are tubular, bulls eye and port-hole sight glass. There are variants on the shapes but they are all similar. The main difference between tubular sight glass and bullseye sight glass is the pressure rating is one differential given the limits but in essence they both allow visibility.
