Our quartz round sight glass, also referred to as a fused quartz sight window or high-temperature sight glass, is a transparent observation component engineered for industrial systems operating under extreme thermal and chemical conditions. Designed to provide a clear, reliable view for process monitoring in boilers, furnaces, and reactors, these windows are manufactured from high-purity fused silica (min. 95% SiO₂), delivering exceptional performance where standard borosilicate glass would fail.
Key Applications & Industry Uses
Quartz round sight glasses are used extensively in environments where maintaining visibility is critical for operational safety and quality control. Typical application scenarios include:
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High-Temperature Furnaces & Kilns: Used as observation windows in ceramics, glass manufacturing, and metal forging to visually monitor internal processes without interrupting thermal cycles.
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Industrial Boilers & Burners: Installed on combustion chambers to provide a clear view of flame conditions and ensure proper combustion efficiency.
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Chemical Reactors & Process Vessels: Ideal for quartz round sight glass ports on tanks and pipelines in petrochemical, pharmaceutical, and food processing industries where corrosion resistance is essential.
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Vacuum Chambers & High-Pressure Systems: Suitable for use in vacuum furnaces, coating chambers, and high-pressure reactors, particularly where UV or infrared light transmission is required.
These glasses are also frequently used as level gauge sight glasses or boiler sight glass windows, enabling operators to visually check fluid levels and internal vessel conditions in real time.
Material & Technical Specifications
These circular fused quartz glass discs are manufactured to stringent industrial tolerances. They can be supplied in standard diameters or fully custom sizes with polished or ground edges. The table below summarizes the key manufacturing parameters and material properties based on available product data.
Manufacturing Parameters
| Parameter | Specification |
|---|---|
| Material | Quartz / Fused Silica (min. 95% SiO₂) |
| Minimum Diameter | 10 mm |
| Maximum Diameter | 350 mm (Custom sizes up to 600 mm available) |
| Minimum Thickness | 3 mm |
| Maximum Thickness | 35 mm |
| Edge Finish | Polished or Ground (as required) |
| Shape Options | Round (Standard), Square, Oblong (Custom) |
Material Properties
| Property | Value |
|---|---|
| SiO₂ Content | ≥ 95% (99%+ in high-purity grades) |
| Density | 2.20 g/cm³ |
| Coefficient of Thermal Expansion (0–300°C) | 0.55 × 10⁻⁶ K⁻¹ |
| Softening Point | 1730 ± 10 °C |
| Annealing Point | 1215 °C |
| Strain Point | 1120 °C |
| Hardness (Mohs) | 7 |
| Thermal Shock Resistance | 480–500 K |
| Hydrolytic Resistance | Class 4 (ISO 719) |
| Acid Resistance | Class S1 (ISO 1776) |
| Alkali Resistance | Class A2 (ISO 695) |
Key Advantages & Performance Characteristics
This high-temperature observation window offers several distinct advantages over other glass types:
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Extreme Temperature Resistance: Capable of continuous operation at 950–1200°C, with short-term exposure tolerance up to 1200–1400°C, making it ideal for applications far exceeding the limits of borosilicate glass.
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Exceptional Thermal Shock Resistance: Withstands rapid temperature fluctuations of 480 K without fracturing due to its extremely low thermal expansion coefficient.
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Superior Chemical Stability: Highly resistant to water, acids, and alkalis, ensuring long service life in corrosive environments.
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Broad-Spectrum Optical Clarity: Offers high light transmittance across visible, ultraviolet (UV), and near-infrared (IR) wavelengths, with excellent clarity for accurate visual monitoring.
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Robust Mechanical Durability: High surface hardness (7 Mohs) and scratch resistance maintain optical clarity and integrity under demanding operating conditions.
Technical Data & Compliance Standards
Our quartz round sight glass products are manufactured in compliance with internationally recognized industrial standards and undergo rigorous quality inspection to ensure reliability in demanding applications.
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Applicable Standards: Manufactured to the construction principles of DIN 7080, with dimensional tolerances conforming to DIN 8902.
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Flange Compatibility: Suitable for carrier flanges conforming to ASME B16.5 and DIN 28121 mounting standards.
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Quality Assurance: Each glass is inspected for material integrity, defect tolerance, and mechanical strength prior to shipment.
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Pressure Rating: Pressure resistance varies with glass diameter and thickness. Engineering consultation is recommended for precise pressure rating calculations based on specific application parameters.
Documentation & Inspection
Upon request, material certifications and test data are available to validate compliance with specified parameters. Documentation may include:
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Certificate of Conformance – Confirming material composition and purity
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Dimensional Inspection Reports – Verifying diameter and thickness tolerances
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Thermal Shock Resistance Data – Validating performance under rapid temperature change
