MAXOS DIN 7080 Sight Glass – Heat-Resistant and High-Pressure Resistant
MAXOS DIN 7080 sight glasses are circular, disc-shaped viewing glasses used for the visual inspection of flow, media levels, or conditions inside industrial equipment.
MAXOS disc-type sight glasses are used in industrial sight glass assemblies, pressure vessels, heat-resistant equipment, and plant systems.
When selecting a sight glass, it is essential to consider not only the diameter but also the thickness, pressure rating, temperature, the medium involved, and the mounting method.
Auer offers MAXOS disc sight glasses in various sizes and pressure ratings. For instance, a Ø45 × 10 mm glass has a permissible pressure of 40 bar, while a Ø45 × 12 mm glass is rated for 50 bar; similarly, a Ø60 × 10 mm glass is rated for 16 bar, whereas a Ø60 × 15 mm glass is rated for 40 bar. This demonstrates that a sight glass cannot be selected based on diameter alone.
What is a MAXOS DIN 7080 sight glass?
The MAXOS DIN 7080 is a disc-type sight glass used in sight glass assemblies, allowing operators to directly observe the medium or processes occurring inside a piece of equipment.
Auer’s MAXOS disc series is designed for applications such as flow indicators, boilers, and level gauges.
These glasses are manufactured in accordance with strict requirements regarding:
flatness;
parallelism;
dimensional tolerances;
mechanical strength;
thermal shock resistance;
the ability to operate at high temperatures.
According to the DIN 7080 standard, Auer specifies the following diameter tolerances for MAXOS discs: ±0.5 mm for diameters up to 150 mm; ±0.8 mm for diameters between 150 mm and 200 mm; and ±1.0 mm for diameters exceeding 200 mm. Construction of MAXOS DIN 7080 Sight Glass
Essentially, a MAXOS DIN 7080 sight glass is a heat-resistant and pressure-resistant technical glass disc, integrated into a sight glass assembly along with sealing and retaining components.
A typical installation assembly consists of:
Flange / fitting body → gasket → MAXOS glass → gasket or protective layer → retaining ring → bolts/nuts
Components:
MAXOS glass: Provides the viewing window.
Gasket: Ensures a seal between the glass and the mounting surface.
Flange: Distributes the clamping force and provides the structural framework for installation.
Retaining ring: Secures the glass in accordance with the design.
Protective mica (shield): May be used in certain configurations to protect the glass.
Practical Tip: When replacing a sight glass, do not rely solely on the diameter of the old glass. It is essential to also verify the thickness, seating surface, gaskets, and the specific type of assembly; a glass with the correct diameter but the wrong thickness or configuration may not be suitable.
Technical Specifications for MAXOS DIN 7080
Flexural strength
≥160 N/mm²
Surface compressive stress
≥100–140 N/mm²
Parallelism
≤0.20 mm
Thermal shock resistance ΔT
230°C
Maximum allowable temperature
300°C
With mica protection
320°C
Diameter tolerance
According to DIN 7080
Thickness tolerance
According to DIN 7080
The values above are technical specifications published by Auer for the MAXOS Disc; general maximum temperature or pressure ratings should not be used as a substitute for verifying the specific glass grade.
MAXOS DIN 7080 Glass Dimensions and Pressure Ratings Table
This section is of great importance to procurement and maintenance engineers.
Reference table for dimensions, thickness, and permissible pressure for MAXOS DIN 7080 sight glasses.
Why do sight glasses with the same diameter have different pressure ratings?
This is a technical detail that often causes confusion for customers.
For example:
Ø45 × 10 mm → 40 bar
but:
Ø45 × 12 mm → 50 bar
Or:
Ø60 × 10 mm → 16 bar
while:
Ø60 × 15 mm → 40 bar.
Thus, diameter is not the only parameter that determines pressure resistance.
Glass thickness, design, installation conditions, and other relevant technical specifications must all be taken into account.
What is the heat resistance of MAXOS DIN 7080 sight glasses?
According to Auer’s technical data, MAXOS discs feature:
Thermal shock resistance (ΔT): 230°C
Maximum permissible temperature: 300°C
When protected by a mica shield: 320°C.
However, engineers should not assume that every MAXOS sight glass can operate at 300°C under all conditions.
The actual operating temperature must be evaluated in conjunction with:
pressure;
dimensions;
thickness;
the medium (fluid/gas);
the design of the sight glass assembly;
gaskets;
the installation method.
MAXOS sight glasses offer high heat resistance and thermal shock resistance, making them suitable for industrial applications involving high-temperature conditions.
Applications of MAXOS DIN 7080 sight glasses in industrial facilities
MAXOS products, manufactured by Auer, are designed for applications requiring visual observation under high-temperature or high-pressure conditions, including steam vessels, pressure tanks, and pipeline systems.
1. Pressure vessels
The glass is installed within a sight glass assembly to monitor:
media levels;
flow;
color;
process status.
2. Heat-resistant vessels
Used in high-temperature equipment where visual monitoring is required without opening the unit.
3. Boilers
Suitable for use in boiler observation assemblies (configured appropriately). Auer offers a dedicated "MAXOS for Boilers" product line.
4. Drying ovens
Sight glasses allow operators to visually inspect the interior of a drying chamber or heating zone.
5. Coffee roasters
In industrial coffee roasters, sight glasses can be used to monitor the roasting process or the flow of the product; however, the glass and its mounting assembly must be selected based on the equipment's actual operating temperature.
6. Industrial pipelines
Can be integrated into flow indicators or sight glass assemblies to observe the flow of media.
7. Reactors
Used in reaction vessels where the design requires direct observation of the internal process.
8. Chemical, food, and pharmaceutical plants
In environments with stringent requirements regarding temperature, chemical exposure, and visibility, the sight glass must be carefully selected to match the specific media and the design of the mounting assembly.
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MAXOS sight glasses are used for observing and monitoring processes within pressure vessels, boilers, drying ovens, and industrial pipelines.
Common Mistakes When Selecting MAXOS DIN 7080 Sight Glasses
❌ 1. Measuring only the diameter
This is incorrect because glasses with the same diameter can have different thicknesses and pressure ratings.
❌ 2. Selecting based on an existing (old) glass without verifying the code
The previously installed glass might have been the wrong type to begin with.
❌ 3. Failing to check the pressure rating
This is an especially dangerous mistake when dealing with pressure vessels and steam systems.
❌ 4. Failing to check the temperature rating
A single, generic temperature specification should not be applied to all configurations.
❌ 5. Using standard glass instead of technical-grade glass
Not all borosilicate glass is designed to withstand the same pressure conditions.
❌ 6. Using the wrong gasket
An unsuitable gasket can cause leaks, even if the glass itself is the correct type.
❌ 7. Uneven tightening of bolts
Uneven tightening force can create unwanted stress on the glass.
❌ 8. Failing to inspect the flange
A seating surface that is warped, dirty, or scratched can compromise the seal and the distribution of force.
❌ 9. Exposing the glass to thermal shock
Hot glass should not be suddenly exposed to a cold environment unless the operating conditions specifically allow for it.
❌ 10. Asking only, “How much does a MAXOS glass cost?”
Choosing a cheaper option that has the wrong dimensions or pressure rating can lead to much higher costs later, due to equipment downtime and the need for replacement.
Expert Advice from Phat Dat on Selecting MAXOS DIN 7080 Sight Glasses
In our experience consulting for industrial plants, Phat Dat often encounters requests where the customer provides only the following:
“MAXOS glass, Ø60.”
This information is insufficient to determine the correct product. Engineers should, at a minimum, verify the following:
① Outer diameter
② Thickness
③ Viewing aperture
④ Operating pressure
⑤ Operating temperature
⑥ Medium (fluid/substance)
⑦ Shape and assembly configuration
⑧ Product code (if applicable)
For instance, a diameter of Ø60 mm alone can correspond to several different configurations—such as 10 mm thickness at 16 bar, 12 mm at 25 bar, or 15 mm at 40 bar—as per the MAXOS DIN 7080 standard.
Therefore, “Ø60” is not a complete product code for the glass.
Frequently Asked Questions about MAXOS DIN 7080 Sight Glasses
1. What is a MAXOS DIN 7080 sight glass?
It is a circular, disc-shaped MAXOS sight glass manufactured according to the dimensions specified in the DIN 7080 standard.
2. What is a MAXOS DIN 7080 sight glass used for?
It is used for the visual observation of flow, liquid levels, or processes occurring inside industrial equipment and systems.
3. What pressure (in bar) can a MAXOS DIN 7080 sight glass withstand?
This depends on the dimensions and thickness. For example, a Ø45 × 10 mm disc is rated for 40 bar, while a Ø45 × 12 mm disc is rated for 50 bar.
4. What temperature can a MAXOS DIN 7080 sight glass withstand?
Auer specifies a maximum allowable temperature of 300°C for MAXOS discs; this increases to 320°C when a mica shield is used.
5. Is the MAXOS DIN 7080 made of borosilicate glass?
The MAXOS line utilizes a borosilicate glass base for many of its disc configurations; Auer also identifies SUPRAX® 8488 as the material used for MAXOS products.
6. Are there MAXOS sight glasses with a diameter of Ø60 mm?
Yes, there are several Ø60 mm configurations available, such as 60 × 10, 60 × 12, and 60 × 15 mm.
7. Is there only one type of Ø60 mm sight glass?
No. Different thicknesses result in different pressure ratings.
8. Can MAXOS DIN 7080 sight glasses be used for pressure vessels?
Yes, they can be used in sight glass assemblies that are compatible with the vessel's design and operating conditions; Auer explicitly states that MAXOS products are suitable for pressure tank applications.
9. Can MAXOS sight glasses be used for boilers?
Yes. Auer offers the MAXOS product line specifically for boiler applications.
10. Can MAXOS be used for drying ovens?
Yes, provided that the temperature, pressure, medium, and mounting assembly align with the design specifications.
11. Can MAXOS be used for coffee roasters?
It can be used for observation ports on such equipment; however, the actual operating temperature and design must be verified before selecting the appropriate glass.
12. Can MAXOS glass be replaced with other types of borosilicate glass?
Replacement should not be based solely on the material. You must verify the dimensions, thickness, pressure, temperature, and installation design.
13. Are custom-sized MAXOS glass panes available?
Auer offers special configurations beyond the standard DIN 7080 range.
14. How do I select the correct MAXOS glass?
Please provide a photo of the existing glass, its dimensions, the product code, and the pressure/temperature specifications so our engineers can verify the requirements.
15. Is nationwide delivery available for MAXOS glass?
Phat Dat provides nationwide delivery across Vietnam based on your specific orders.
Why choose Phat Dat?
✔ Expert consultation on glass selection based on your facility's specific applications
✔ Verification of dimensions, thickness, pressure, and temperature
✔ Assistance with cross-referencing MAXOS/DIN 7080 product codes
✔ Thorough product inspection prior to shipment
✔ Support for replacing existing glass
✔ Nationwide delivery
✔ Extensive experience in supplying equipment for boilers and industrial systems
Request a Quote for MAXOS DIN 7080 Sight Glass
Do you need to replace a sight glass for any of the following?
Pressure vessels? Heat-resistant tanks? Boilers? Drying ovens? Coffee roasters? Reactors? Pipelines?
Please do not simply send a message saying:
“Give me a price for MAXOS glass.” Simply provide Phat Dat with the following details:
An image of the existing glass, its dimensions, operating temperature, pressure, and any markings/codes present on the glass (if applicable).
Phat Dat’s engineers will verify the specifications and recommend the appropriate MAXOS DIN 7080 sight glass before providing a price quote.
→ Contact Phat Dat for consultation and a quote on MAXOS DIN 7080 sight glass.
