Our Products
DIN 28121 Round Vessel Sight Glass
Non binding • Usually a response within 24 hours
Certified quality
Technical data
DIN 28121 Pressure Vessel Sight Glass Overview
The DIN 28121 Pressure Vessel Sight Glass is a circular bolted sight glass assembly specifically designed for visual observation inside pressure vessels, reactors, tanks, separators, and processing equipment.
Manufactured according to DIN 28121 requirements, the assembly consists of a precision-machined base flange, cover flange, high-strength sight glass, sealing gaskets, and fastening bolts. The complete unit is pre-assembled to ensure reliable sealing performance and long service life.
The sight glass enables operators to monitor liquid levels, mixing processes, foam formation, product color, crystallization, and reaction conditions without interrupting operations or opening the vessel.
Available with borosilicate glass DIN 7080, tempered safety glass, stainless steel flanges, PTFE seals, and optional explosion-proof LED lights, DIN 28121 sight glasses are widely used in chemical, pharmaceutical, food processing, biotechnology, petrochemical, and energy industries. Typical operating pressures range from PN10 to PN25 depending on size and configuration.
DIN 28121 Pressure 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 | Pressure: 10 bar or 25 bar; vacuum 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 28121 Pressure Vessel Sight Glass— Component Materials
| Materials | |
|---|---|
| Component | Material & Specification |
| Base flange, version A (1) | boiler plate H II DIN 17155; stainless steel 1.4571 to DIN 17440 or other AB1: sealing rib to DIN EN 1092-1 AC: tongue to DIN EN 1092-1 AE: male socket to DIN EN 1092-1 |
| Gasket, side with product contact (2.1) | PTFE envelope resilient gasket with corrugated support ring |
| Gasket, atmospheric side (2.2) | KLINGERsil C-4400 |
| Sight glass disc (3) | borosilicate glass: toughened DIN 7080 |
| Mating flange (4) | boiler plate H II, stainless steel 1.4571 or other |
| Compression bolts (5) | steel 5.6 |
Dimensions for sight glass fitting, circular, DIN 28120/PN 10/16 or similar DIN 28120/PN 6
| Size | 1 | 2 | 3 | 4 | 5 | 6 | 7 | |
|---|---|---|---|---|---|---|---|---|
| Nominal bore | DN | 40 | 50 | 80 | 100 | 125 | 150 | 200 |
| Nominal pressure (bar) | PN | 10/25 | 10/25 | 10/25 | 10/25 | 10/25 | 10/25 | 10/25 |
| Viewing diameter | d1 | 48 | 65 | 80 | 100 | 125 | 125 | 150 |
| Sight glass disc | d3 | 63 | 80 | 100 | 125 | 150 | 150 | 175 |
| s | 10/12 | 12/15 | 15/20 | 15/25 | 20/30 | 20/30 | 20/30 | |
| Flanges | D | 150 | 165 | 200 | 220/235 | 250/270 | 285/300 | 340/360 |
| k | 110 | 125 | 160 | 180/190 | 210/220 | 240/250 | 295/310 | |
| h3 | 36/38 | 38/41 | 46/50 | 46/59 | 54/66 | 54/66 | 54/66 | |
| Fastening bolts (not included in supply) | no. | 4 | 4 | 8 | 8 | 8 | 8 | 8/12 |
| size | M 16 | M 16 | M 16 | M 16/M 20 | M 16/M 24 | M 20/M 24 | M 20/M 24 | |
| d9 | 18 | 18 | 18 | 18/22 | 18/26 | 22/26 | 22/26 | |
| Gaskets | d1 | 48 | 65 | 80 | 100 | 125 | 125 | 150 |
| d10 | 65 | 82 | 102 | 127 | 152 | 152 | 177 |
KEY FEATURES
DIN 28121 Standard Compliance
Designed and manufactured according to DIN 28121 dimensional standards
High Pressure Capability
Suitable for pressure ratings up to PN25, with customized designs available for higher pressure applications.
Excellent Chemical Resistance
Borosilicate glass DIN 7080 provides outstanding resistance to most acids, solvents, and industrial chemicals.
Superior Optical Clarity
Allows distortion-free observation of internal processes for safer and more efficient operation.
Reliable Sealing System
Equipped with PTFE, graphite, silicone, or customized gaskets to ensure leak-free performance.
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: DIN 28121 is a standardized circular bolted sight glass assembly used for observing the interior of tanks, vessels, and reactors under pressure.
A:Standard designs support PN10 and PN16, with customized high-pressure solutions available.
A:Common materials include:Borosilicate Glass DIN 7080Tempered Safety Glass,DIN 8902,Quartz Glass,Sapphire Glass (custom)
A: Standard pressure ratings include PN10 and PN25. Higher pressure designs can be engineered according to operating requirements.
A: Yes. Explosion-proof LED lights and non-Ex sight glass lights can be integrated for improved visibility.
Need Custom DIN 28121 Round Vessel Sight Glass Solutuions?
Send us your drawings or technical requirements for fast quotation and engineering support.