Industrial Glass
Pressure- and heat-rated sight glass, gauge glass, and sight glass tubes for boilers, furnaces, reactors, tanks, and process vessels. We supply borosilicate, fused quartz, and glass-ceramic sight glass in round discs, gauge plates, tubes, and custom shapes according to DIN, ASME, or your own drawing.
Sight And Gauge Glass For Process Monitoring
Industrial sight glass gives operators a safe way to observe liquid level, flame condition, flow movement, color change, or process status without opening the vessel. It is used in boilers, reactors, furnaces, pipelines, pressure tanks, chemical equipment, and thermal processing systems where the glass must stay sealed under pressure, heat, and media exposure.
A sight glass is usually installed as a sealed window in a vessel, flange, pipe, or inspection port. Gauge glass is used in level indicators to show the liquid level directly. Both products need the right balance of temperature resistance, pressure rating, chemical resistance, optical clarity, and mechanical strength.
The correct glass depends on three main factors: working temperature, working pressure, and the medium inside the vessel. We supply common borosilicate sight glass for standard industrial use, fused quartz for high-temperature or UV applications, and glass-ceramic for thermal shock and furnace observation conditions.
Industrial Glass Families
Sight Glass
Gauge Glass
Boiler Glass
Furnace Observation Glass
Industrial Windows
Custom Equipment Glass
Need Help?
Don't hesitate to contact us for more information about our company or industrial sight glass.
Selection Guide
Choose pressure vessel sight glass according to the medium, working pressure, temperature, and installation environment.
For flammable, toxic, or hazardous media, use small-diameter high-temperature and high-pressure sight glass with proper protective devices to prevent leakage. For low-pressure vessels, larger low-pressure sight glass is usually suitable.
Moulded Glass Solutions
We also provide custom moulded glass solutions for industrial sight glass and high-temperature applications. From drawing review and mould development to sample testing and batch supply, we help customers produce shaped glass parts that cannot be made by flat cutting alone.Tell us the vessel - the temperature, pressure, medium, flange size, and the standard you're working to - and we'll supply the right sight or gauge glass to match. We hold stock of common borosilicate sizes for fast delivery, and we make quartz and glass-ceramic parts to your drawing when the duty calls for it.
Sight & Gauge Glass By Material
Borosilicate Sight Glass
Quartz Sight Glass
Glass Ceramic Sight Glass
Glass-ceramic combines high temperature resistance with near-zero thermal expansion. It shrugs off sudden heating and cooling that would crack other glasses, so it's used where the temperature swings are as extreme as the peak temperature itself.
Specifications
| Property | Borosilicate Glass | Fused Quartz | Glass-Ceramic |
|---|---|---|---|
| Max continuous temperature | ~280°C for gauge glass use; higher grades can reach ~450°C | ~1,000°C | ~700°C or higher |
| Thermal shock resistance | Good | Excellent | Excellent |
| Thermal expansion / CTE | ~3.3 × 10⁻⁶ /K | ~0.55 × 10⁻⁶ /K | Near zero |
| Chemical resistance | Resistant to most acids, water and neutral solutions; not suitable for HF or hot alkali | Excellent chemical resistance; not suitable for HF or strong hot alkali | Good general chemical resistance |
| UV transmission | Partial UV transmission | High UV transmission, down to ~180 nm | Limited |
| Forms available | Round sight discs, gauge plates, tubes, custom parts | Round discs, tubes, rods, windows, custom shapes | Round discs, plates, windows |
| Common standards | DIN 7080, DIN 7081, ASME type sight glass | Custom to drawing | Custom to drawing |
| Diameter range | 17 mm to 250 mm+ | Custom to drawing | Custom to drawing |
| Thickness range | 6 mm to 30 mm+ | Custom to drawing | Custom to drawing |
Custom Sight & Gauge Glass
We manufacture sight glass and gauge glass according to standard dimensions, customer drawings, or equipment samples. Common products include round sight glass discs, transparent gauge glass, reflex gauge glass, tubular sight glass, boiler sight glass, furnace observation glass, and custom moulded glass parts.
For standard industrial equipment, borosilicate glass is usually the most practical choice because it balances clarity, thermal shock resistance, chemical resistance, and cost. For high-temperature observation, fused quartz or glass-ceramic may be required. For steam, chemical, or pressure service, the glass size, thickness, gasket contact area, and installation design must be checked before production.
We can support cutting, edge grinding, polishing, drilling, shaping, moulding, and custom packing. If you already have a drawing, standard number, flange size, or old sample, send it to us and we can match the glass to your equipment.
Selection System
Use the operating requirement first, then confirm the glass family, processing route and inspection method.
Confirm pressure, unsupported diameter, seal arrangement and required safety factor.
State continuous temperature, peak temperature and thermal cycling, not only a single maximum.
Identify the process medium, cleaning chemicals and surface contact duration.
Engineering Data System
Operating Data
Temperature, pressure and medium define the selection boundary.
Assembly
Flange, gasket, support and edge condition influence the glass.
Viewing
Visible, UV or IR requirements may change material and coating.
Traceability
Agree on inspection records and marking before production.
Related Technical Pages
Borosilicate Glass
Standard low-expansion industrial viewing material.
Quartz Glass
High-temperature and UV-capable material.
Custom Components
Drawing-based equipment glass.
Drilling
Mounting holes, slots and cut-outs.
Selection FAQ
What information should I send for a quotation?
Send the drawing, glass type if known, dimensions, thickness, tolerance, quantity, application and any edge, hole, printing, coating or strengthening requirement.
Can Specialglass help select the material?
Yes. Provide the operating temperature, optical requirement, chemical exposure, mechanical load and installation method. The engineering team can narrow the suitable glass families before quoting.
Are custom shapes available?
Custom discs, plates, windows, holes, slots, steps and CNC profiles can be reviewed against the selected material and process route.
Saving your time and cost is our common pursuit.
Tell us the material, size, thickness, tolerance, quantity, application, and any holes, slots, edges, coating, printing, or polishing requirements. We can manufacture custom glass components from your drawing, CAD file, sketch, or sample.
- Address
- Yunpu Industrial Zone, Nangang, Huangpu District, Guangzhou
- Call Us
- +86 19860070065
- Email Address
- info@specialglass.net
- +86 19860070065
- +86 19860070065