Round Tank Sight Glasses for Monitoring Processes in Pressure Vessels, Boilers, Tanks and Silos
Round vessel sight glasses are used for the safe visual monitoring of processes inside pressure vessels, boilers, tanks, silos, and equipment.
At ACI, you will find various designs for insertion or welding-in, for welding-on, for flange mounting, as well as for special requirements regarding pressure, temperature, and installation conditions.
These include classic standard designs in accordance with DIN 28120 and DIN 28121, as well as variants for biogas applications, high-pressure service, vacuum service and special applications. This allows our round vessel sight glasses to be matched precisely to the respective process conditions and technical requirements of your system.
If no suitable standard version is available, we will work with you to develop a solution tailored to your application.
For pressureless applications up to max. 0.49 barg
Light execution for operating pressures up to 2.5 barg
Light design for vacuum
Execution according to DIN 28120 for operating pressures up to 16 barg
Execution according to DIN 28121 for working pressure up to 25 barg
Execution similar to DIN 28121 for working pressure up to 20 barg
High pressure tankl sight glass PN 40 | PN 63 | PN 100 | PN 160
High pressure vessel sight glass class 150 | 300 | 400 | 600 | 900 | 1500 lbs
High-Temperature container sight glass for working pressures up to 25 barg
Manhole sight glass for working pressures up to 16 barg
Screwed sight glass Type 327 for working pressures up to 10 barg
Clamp connection DIN 32676 for working pressures up to 16 barg
Tank sight glass PN 16 | PN 40 | PN 63 | PN 100 | PN 160 | PN 250 | PN 320
Tank sight glass for vacuum application
Tank sight glass PN 16 | PN 25 | PN 40
Tank sight glass PN 16 | PN 40 | PN 63 | PN 100 | PN 160
Tank sight glass PN 16 | PN 40 | PN 63 | PN 100 | PN 160
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Technical Diversity for Industry and Plant Engineering
ACI’s round vessel sight glasses enable safe visual inspection of pressure vessels, tanks, silos, boilers, and equipment.
Depending on the installation situation, pressure rating, and temperature, various designs are available for industrial applications—ranging from classic welded and flanged solutions to variants for high pressure, vacuum, and elevated temperatures.
For welded applications, Type 320, manufactured in accordance with DIN 28120, is particularly suitable as a proven standard design for operating pressures up to 16 bar gauge.
For lower pressure requirements, Types 317 and 318 are available as suitable variants for unpressurized or low-pressure applications. If a mounting flange is already present on the vessel, Type 321, conforming to DIN 28121, is a suitable solution.
For more demanding operating conditions, ACI offers reinforced versions such as Types 322, 323, or Type 390 for high pressures and/or elevated temperatures.
The range is complemented by vacuum versions such as Type 390V, manhole sight glasses such as Type 325, hygienic and sterile variants such as Type 327 and Type 328, as well as solutions for pipe mounting with Type 391.
Materials and design according to requirements
The selection of a suitable tank sight glass depends not only on the design but also on the medium, pressure, temperature, and installation conditions.
Depending on the application, different types of glass and materials are used, including borosilicate glass in accordance with DIN 7080, soda-lime glass in accordance with DIN 8902, or quartz glass, as well as specially designed stainless steel and sealing configurations.
For demanding applications, additional protective and accessory solutions are available depending on the type, such as glow protection screens for high temperatures, FEP or Halar® coatings for aggressive chemical media such as caustic solutions (sodium hydroxide). Accessories such as wipers, spray devices, and lights are available for cleaning. This allows the sight glass assembly to be specifically adapted to the technical requirements of your system.
Technical consultation to help you choose the right design
Not every application can be accommodated by a standard model. Precise technical selection is crucial, especially when dealing with high pressures, specific temperature ranges, vacuum applications, or non-standard connection dimensions. ACI can assist you in designing and selecting the right round vessel sight glass for your system.
Frequently Asked Questions About Round Tank Sight Glasses
Depending on the model, round sight glass assemblies can be combined with LED lights. You can find matching accessories and equipment options directly on the respective product pages. This significantly improves visibility in dark tanks.
For high temperatures, depending on the application, options include borosilicate glass (unhardened) or thermally toughened borosilicate glass (DIN 7080), as well as quartz glass or sapphire glass for unpressurized applications. The appropriate type of glass depends on the temperature, medium, pressure, and installation conditions.
The most important factors are the installation conditions, pressure, temperature, medium, connection type, and the desired glass or material type. Accessories such as lights or cleaning solutions may also be useful depending on the application.
Yes. ACI offers a range of round vessel sight glasses, including the Type 325 manhole sight glass and hygienic versions such as the Type 327 and Type 328.
Yes. The current product range includes high-pressure models such as Type 322, Type 390, Type 392, and Type 394, as well as vacuum models such as Type 318V and Type 390V.
Models compliant with DIN 28120 (our Type 320) are particularly suitable for monitoring processes under pressure and at high temperatures. They enable precise visual inspection of the interior of containers, tanks, silos, or boilers. Upon request or as an option, they can be combined with an LED light to further improve visibility.
If the tank sight glass is to be mounted on an existing flange, a model compliant with DIN 28121 (our Type 321) is the solution.