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DIN 28120 Vessel Sight Glass
DIN 28120 Round Vessel Sight Glass is designed for reliable visual monitoring of fluid levels and processes in industrial vessels. Manufactured in accordance with DIN standards, it ensures high pressure resistance, excellent sealing performance, and long service life across chemical, pharmaceutical, and processing industries.
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Technical data
DIN 28120 Round Vessel Sight Glass Overview
The DIN 28120 vessel sight glass is a high-performance circular inspection window designed for welding installation on industrial pressure vessels, reactors, and storage tanks. It provides a reliable and safe way to visually monitor internal processes such as liquid levels, reaction status, foam formation, and color changes without opening the system.
Manufactured according to DIN 28120 standards, this sight glass assembly ensures precise dimensional accuracy and excellent mechanical stability under pressure. It is widely used in chemical processing, pharmaceuticals, petrochemicals, food production, and energy industries.
The system typically consists of a base flange, cover flange, borosilicate glass disc (DIN 7080), high-temperature gaskets, and fastening bolts. With robust sealing and high optical clarity, it guarantees long-term durability even in demanding environments.
Available in DN50–DN200 sizes, the DIN 28120 sight glass supports PN10 and PN16 pressure ratings, with customized high-pressure designs available upon request.c
DIN 28120 Round Vessel Sight Glass— Technical Data
| Item | Details |
|---|---|
| Application | For viewing of internals of pressure vessels, tanks, silos, stirred vessels, separators pipelines etc. |
| Operating conditions – Pressure | 10 bar or 16 bar, depends on size, higher pressure rating on request; vacuum |
| Operating conditions – Temperature | max. 150°C with sodalime glass DIN 8902 max. 280°C with borosilicate glass DIN 7080 higher temperatures on request |
| Possible combinations | Can be combined with Lumiglas luminaires when used in explosion hazardous as well as non explosion hazardous areas. The cover flange is then drilled and tapped to suit luminaire mounting bracket. |
DIN 28120 Round Vessel Sight Glass— Component Materials
| Item | Part | Material |
|---|---|---|
| 1 | base flange (welding flange) | carbon steel S235JR+N (RSt 37-2), stainless steel or other |
| 2.1, 2.2 | fastening bolts | carbon steel 5.6/5 or stainless steel A2 |
| 3.1, 3.2 | gaskets | KLINGERsil C-4400; silicone, PTFE or other |
| 4 | sight glass disc | – sodalime glass: toughened DIN 8902 – borosilicate glass: toughened DIN 7080 |
| 5 | cover flange | carbon steel S235JR+N (RSt 37-2); stainless steel 1.4541 or other |
| 6 | vesel wall | — |
Dimensions for sight glass fitting, circular, DIN 28120/PN 10/16 or similar DIN 28120/PN 6
| size | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| normal bore (DN) | 50 | 80 | 100 | 125 | 150 | 200 |
| pressure rating (bar) PN | 10/16 | 10/16 | 10/16 | (6) 10/16 | (6) 10/16 | (6) 10 |
| viewing diameter d1 | 80 | 100 | 125 | 150 | 175 | 225 |
| sight glass disc d3 | 100 | 125 | 150 | 175 | 200 | 250 |
| sight glass disc s | 15/15 | 15/20 | 20/25 | (20) 20/25 | (20) 25/30 | (25) 30 |
| flanges D | 165 | 200 | 220 | 250 | 285 | 340 |
| flanges k | 125 | 160 | 180 | 210 | 240 | 295 |
| flanges d6 | 18 | 18 | 18 | 18 | 22 | 22 |
| flanges h1 | 16/16 | 20/20 | 22/22 | (18) 25/25 | (18) 30/30 | (20) 35 |
| flanges h2 | 30 | 30 | 30 | 30 | 36 | 36 |
| fastening bolts no. | 4 | 8 | 8 | 8 | 8 | 8 |
| fastening bolts size | M 16 | M 16 | M 16 | M 16 | M 20 | M 20 |
| gaskets d1 | 80 | 100 | 125 | 150 | 175 | 225 |
| gaskets d7 | 102 | 127 | 152 | 177 | 202 | 252 |
| tightening torque (Nm, μ 0.1) | 28/32 | 20/23 | 26/30 | 32/34 | 47/54 | 63 |
KEY FEATURES
Thermal Stability
High resistance to thermal shock for extreme temperature environments
High Mechanical Strength
Suitable for pressure-loaded industrial systems
Chemical Resistance
Stable performance in corrosive chemical environments
Excellent Transparency
Clear visibility for process monitoring
Precision Manufacturing
Accurate dimensions and polished sealing surfaces
Custom Design Support
OEM / ODM customization available
Custom Manufacturing Service
We provide tailor-made solutions according to drawings or technical requirements.
- Custom diameter
- Custom thickness
- Special pressure design
- Edge polishing
- Optical finishing
- OEM / ODM support
- Custom packaging
TYPICAL APPLICATIONS
- Pressure Vessels
- Chemical Reactors
- Boilers & Steam Systems
- Pipeline Sight Glass Assemblies
- Pharmaceutical Equipment
- Food & Beverage Processing
- Industrial Observation Ports
FAQ
A: The center hole is commonly used for mounting wipers, sensors, probes, or special accessories while maintaining visibility inside the vessel.
A:Standard designs support PN10 and PN16, with customized high-pressure solutions available.
A: Yes, borosilicate glass can typically withstand up to 280°C depending on operating conditions.
A: Yes. All sight glass discs are supplied with precision ground or polished edges for reliable installation.
A: Yes, optional accessories include LED lights, cleaning wipers, and explosion-proof illumination systems.
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