Tempered Borosilicate Sight Glass
Manufactured in 3.3 Borosilicate Glass, these sight glasses are used in several applications where a good chemical resistance and low thermal expansion coefficient are required.
OUR WARRANTY
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Douglass warrants merchandise against defective workmanship and materials that become apparent within a period of 12 months from the date of receipt of invoice by the purchaser (hereinafter referred to as the warranty period). All liabilities under the warranty provisions shall expire when the warranty period has expired. Please feel free to contact us if you have any questions or comments.
SHIPPING AND PACKAGING
At Douglass, we use a unique and patented packaging method that minimizes the risk of glass damage during shipping. This system ensures your products arrive in perfect condition, just as we would like to receive them ourselves.
We understand that not all glass is the same, so we tailor our packaging techniques based on the type and quantity of products you order. This ensures maximum protection for every shipment.
Manufactured from 3.3 borosilicate glass, these sight glasses are used in various applications where good chemical resistance and a low coefficient of thermal expansion are required. Poor chemical resistance can cause the glass to react and release unwanted substances in the process, such as when non-borosilicate glass reacts with water. Special dimensions are available upon request, where the minimum diameter is 2/5" and the maximum diameter is 13.78". Thickness can be manufactured from a minimum of 1/8" and a maximum of 1 3/8".
Physical properties
| Property | Testing method | Obtained value |
|---|---|---|
| Thermic dilatation coefficient | ISO 7991 | 3.3 × 10⁻⁶ |
| Density at 25°C | SN 7005 13 | 2.23 g/cm³ |
| Refractive index (λ = 587.6 nm) nd | — | 1.472 |
| Maximum annealing temperature | ISO 7884-8 | 1040 ºF |
| Short-term maximum temperature | ISO 7884-7 | 932 ºF |
| Thermal shock resistance | ISO 7884-4 | 5.67 ºF |
| Young's modulus | — | 63 150 MPa |
| Poisson constant | — | 0.2 |
| Thermal conductivity 20°C – 100°C λ | — | (1.2) (w·m⁻¹)(K⁻¹) |
| Photoelastic constant | DIN 52314 | (4.00 × 10⁻⁶) (mm²/N) |
| Specific electrical resistance 10⁸ Ωcm | DIN 52326 | 482 ºF |
| Dimensional tolerance diameter | DIN 7080 | PASS |
Optical / chemical properties
| Property | Testing method | Obtained value |
|---|---|---|
| Hydrolytic resistance | ISO 719 | HGB 1 |
| Acid resistance | ISO 1776 | CLASS S1 |
| Alkaline resistance | ISO 695 | CLASS 2 |
| Chemical composition SiO₂ | — | Minimum content 80% |
| Chemical composition B₂O₃ | — | Minimum content 13% |
| Chemical composition Na₂O + K₂O | — | Minimum content 4.5% |
Borosilicate sight glass — DIN 7080
DIN parameters cover pressure resistance in terms of total diameter, observable diameter, and glass thickness, as well as permissible imperfections, chemical attack, markings, and dimensional tolerances.
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