Spray System for Sight Glass type 121-I | Noris

Spray System for Sight Glass Noris Type 121-I

The Noris Type 121-I is a spray assembly designed for circular tank sight glasses according to DIN 28121. It is not a standalone level gauge, but an auxiliary device for cleaning or rinsing the internal glass surface in cases of contamination by foam, solids, deposits, or condensates.

Configurations

Type A with Spacer
A spacer with integrated spray nozzle is inserted without modifying the base sight glass fitting (DIN 28121). This configuration allows retrofit installation on existing assemblies, provided dimensions, pressure rating, and material compatibility are verified.

Type B Integrated in Fitting
The spray nozzle is built into the sight glass body. The spray medium connection can be axial or radial, depending on tank geometry and available piping.

Technical Selection Criteria

• Application standard: DIN 28121
• Compatibility: all pipe sizes, all nominal pressure classes, and all material grades of the corresponding fitting series
• Spray medium: water, cleaning solution, or other compatible process auxiliary
• Spray connection: axial or radial
• Actuator: not integrated in Type 121-I; control is via external manual, solenoid, or pneumatic valve on the spray line

Typical Applications

• Tanks with foaming media or products leaving film on glass
• Mixing vessels, chemical processes, and food/beverage applications requiring visual confirmation
• Installations where disassembly for cleaning increases maintenance time
• Inspection points requiring periodic rinsing prior to visual checks

Maintenance

Check spray delivery, nozzle blockage, connection tightness, compatibility of spray medium with gaskets and metals, and inspect for corrosion or scaling at the nozzle outlet.

FAQ

Can it be retrofitted to existing sight glasses?
Yes, with the Type A spacer version, provided the existing fitting is compatible.

Does it affect the operating pressure of the sight glass?
Not by itself. The design pressure must match both the base fitting and the spray line.

When is it preferred over a standard sight glass?
When glass surfaces are subject to fouling during operation and cleaning is required without opening the vessel.