High temperature sight glass fitting - type 323

Short description - High Temperature sight glass - type 323 - for flange connection

The ACI tank sight glass type 323 is a variation of the type 321, intended for an extended range of applications, especially at elevated temperatures. They are used to observe and illuminate the interior of closed tanks (boilers, tanks, silos, etc.).

The PTFE-encapsulated gaskets normally used in Type 321 are no longer safe to use above a temperature of 200°C. The PTFE-encapsulated gaskets are not suitable for use in the case of the following applications In order to eliminate this disadvantage, we use high-quality graphite composite seals for the Type 323 so that the operating range of the borosilicate glass plates according to DIN 7080 up to 280°C, or even 300°C with a mica disc, can be fully utilised.

Even at temperatures above the limits of DIN 7080, the Type 323 can be used without problems up to 400°C due to high-performance materials such as quartz glass or sapphire glass. For higher temperatures, please contact us.

Due to the sealing in the force shunt, the Type 323 brings you the same advantages as our proven Type 321. Here, too, the glass plate remains optimally protected on the entire circumference and the fitting can easily be installed or replaced like a single component. The valve is completely assembled at the factory and, on request, subjected to a test for pressure resistance and tightness so that you can rely 100% on our quality.

As with the Type 321, the Type 323 can also be supplied on request with lighting based on LED or halogen lamps directly from our production.

Read on for more technical information and our vew our product video.

Technical Data


Base flange:
1.4724 / 1.4762 / 1.4828 / 1.4841 / 1.4845 / 1.4571 / 2.4605

Cover flange:
1.4724 / 1.4762 / 1.4828 / 1.4841 / 1.4845 / 1.4571 / 2.4605

Sight glass:

Quartz glass, sapphire glass


Graphite composite gasket


assembly for bolting straight onto DIN EN 1092 or ASME flanges

Nominal size

DN40 up to DN200


PN10 or on request


400°C / Special versions up to 1000 ° C are possible on request

Optional versions are possible.

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Type 323 - High Temperature Sight Glass