Soda Lime Circular Sight Glass Disc - DIN8902

SODA LIME CIRCULAR SIGHT GLASS DISC-DIN8902 FOR OBSERVING LIQUID FLOW AND LEVEL

Manufactured in Soda Lime Glass, these sight glasses are used in several applications where the cost-reduction is important, and the glass will not be in contact with food, drugs, chemicals, or temperatures above 300 F.

Special dimensions of glasses are available upon request, where the minimum diameter is 10mm, and the maximum diameter is 350mm. The thickness can be manufactured to a minimum of 3mm and a maximum of 25mm. Do not hesitate to contact us for recommendations as to which sight glass fits your application the best.

MANUFACTURED IN ACCORDANCE TO DIN 8902

In order to achieve the standardization of this type of type of sigh glasses in all the different industries, the German regulatory institute, DIN for its acronym in German, designed standard parameters for the manufacture of this type of glass.

The main issues this norm regulates is the pressure resistance in terms of the total diameter of the glass, the observable diameter of the glass, and the glass thickness. It also dictates permissible imperfections in the glass, chemical attack, markings, and dimensional tolerances.

CHEMICAL ATTACK ON GLASS

The extent to which glass in boiler sight glasses is attacked when exposed to aqueous media will normally increase exponentially as the temperature and pH of the medium rises and the attack may be considerably accelerated by chemical additives such as those used in various ways and amounts in water treatment plants.
The resultant severe erosion and consequential dimensional changes may endanger the working safety of the sight glass and may result in rupture. The most important influencing variables are, however, the pH and temperature, but, for other complex reasons, the temperature plays a major role at temperatures markedly above 200 °C. To illustrate this, the figure below shows the erosion of a glass surface at 170 °C for two different pH levels, while the broken line shows the effect of increasing the temperature to 220 °C at a pH of 10 under laboratory conditions.

(DIAM MIN 10mm MAX 350mm) / (THICKNESS MIN 3mm Max 35MM)