Sight glass is a device used between any kind of non transparent pipeline to observe the flow of liquid. This can be used both in horizontal as well as vertical pipeline. Sight glass is constructed in such a way that it gives a complete view from every angle.
A sight glass consists of one glass pipe section, one metal frame, a pair of PTFE bushes and washers and an acrylic cover. Borosilicate pipe section is highly heat resistant, has excellent chemical resistance and has low thermal expansion. Metal frame is composed of two flanges which are welded with studs so that the stresses and vibrations of the pipeline do not transfer to the glass pipe section. Its check nut keeps the glass pipe section in compression and provides ease in replacement.