Viewports: Sight Glass Indicators
The strongest, most secure sanitary sight glass indicator available, Viewport’s mechanically prestressed windows are available in a sanitary clamp design for sight ports in processing applications or inline visual flow indicators.
Unlike some other sight glasses, Viewport sight glasses meet the USP Type 1 standard for pharmaceutical use.
Described as offering the optics of glass and the strength of steel, these glass elements provide a level of safety, and a useful service life, well beyond that provided by conventional tempered glass or plastic used as sight glass indicators. Even at the most extreme temperatures (as high as 536° F) or in overpressure situations, sudden, total failure – that involving leakage or explosive shattering of the glass – essentially never occurs.
| Standard Tube OD | d1 Inch/MM | d2 Inch/MM | d3 Inch/MM | S Inch/MM | PSIG@ 536 F |
|---|---|---|---|---|---|
| 1/2″, 3/4″ | 0.98″/ 25 mm | 0.71″/ 18 mm | 0.39″/ 10 mm | 0.39″/ 10 mm | 230 |
| 1″, 1 1/2″ | 1.99″/ 51 mm | 1.61″/ 41 mm | 0.98″/ 25 mm | 0.39″/ 10 mm | 230 |
| 2″ | 2.52″/ 64 mm | 2.05″/ 52 mm | 1.18″/ 30 mm | 0.39″/ 10 mm | 200 |
| 2 1/2″ | 3.05″/ 78 mm | 2.72″/ 69 mm | 1.38″/ 35 mm | 0.39″/ 10 mm | 200 |
| 3″ | 3.58″/ 91 mm | 2.99″/ 76 mm | 1.57″/ 40 mm | 0.39″/ 10 mm | 150 |
| 3 1/2″ | 4.17″/ 106 mm | 3.54″/ 90 mm | 1.97″/ 50 mm | 0.39″/ 10 mm | 150 |
| 4″ | 4.69″/ 119 mm | 4.02″/ 102 mm | 2.17″/ 55 mm | 0.47″/ 12 mm | 150 |
| 6″ | 6.57″/ 167 mm | 5.98″/ 152 mm | 2.95″/ 75 mm | 0.63″/ 16 mm | 90 |
| 8″ | 8.56″/ 218 mm | 7.80″/ 198 mm | 3.94″/ 100 mm | 0.71″/ 18 mm | 90 |
| 10″ | 10.55″/ 268 mm | 9.65″/ 245 mm | 4.72″/ 120 mm | 0.79″/ 20 mm | 90 |
| 12″ | 12.56″/ 319 mm | 11.81″/ 300 mm | 5.51″/ 140 mm | 0.87″/ 22 mm | 80 |
| *Temperature and pressure apply to sight glass only. | |||||
Viewport windows are formed by melting borosilicate glass into a precisely formed metal ring. As the glass cools, it solidifies, preventing the metal ring from contracting back to its theoretical size. The result is a uniform, mechanically prestressed fusion of glass and metal that combines excellent optical characteristics with greatly enhanced physical characteristics. A standout of sight glass indicators, the Viewport discs have an uninterrupted surface with no crevice to trap bacteria, epoxies, resins, or glue – a true fusion. The standard surface finish is 10 Ra μ-in (0.25 Ra μm).
Electropolishing available upon request.