Key Features of Extra-Hard Borosilicate Sight Glass

• The quality of a sight glass depends mainly on the chemical composition and mechanical strength of the glass material.
• Uniform Glass Quality is maintained through glass analyses and acid/alkali tests. The mechanical strength is attained through thermal pre-stressing. In this procedure the sight glass is brought to a high temperature then quickly cooled - rather as in the hardening of steel. This increases the bending strength and shock resistance of the glass to the values stipulated in the standard.
• Optical control of the pre-stressing is carried out with the aid of a polarisation filter: the stress lines are made visible at the edge of the sight glass as interference colours. Glass which has not been thermally pre-stressed shows no stress lines and has much lower mechanical strength.
• Oil refineries
• Petro-chemical plants
• Pharmaceutical manufacture
• Chemical processing
• Mechanical engineering, especially manufacture of boilers and storage vessels
• Foodstuffs and beverages industry
• Water engineering
• Paper and cellulose industry
• Textiles industry
• Marine engineering
• Nuclear engineering