Sight Flow Indicators - 025-B | Noris

NORIS Bauform 25-B – Tubular Flow Indicator with Ball

The NORIS 025-B is a dual-sided tubular flow indicator with DIN PN10/PN16 flanges and a Safety Seal-System according to DIN 28121. It is used in vertical pipelines for visual monitoring of liquids and gases. The flow must be from bottom to top, allowing the internal ball to rise and indicate flow presence.

Technical Specifications

• Connection: PN10/PN16 flanges
• Max Pressure: 6 bar
• Max Temperature: 200 °C
• Installation: Vertical only
• Flow Direction: Bottom to top
• Sizes: DN25, DN40, DN50, DN80, DN100
• Flange Material: WN 1.4571
• Bolts: A4-70
• Viewing Tube: Borosilicate Glass
• Ball and Seats: PTFE
• Gaskets: PTFE covered

Operating Principle

When flow begins, the ball rises within the glass tube providing immediate visual indication. The seat geometry allows the ball to function as a check element, though it does not replace a dedicated check valve in critical applications.

Applications

Suitable for locations requiring local flow confirmation in:

• Process or cooling water
• Compatible chemical liquids
• Low-pressure gases
• Filling, discharge, or recirculation lines
• Vertical lines where ball indication is more readable than a simple tubular indicator

Difference from 025 / 025-A

Compared to the 025, the 025-B features an indicator ball and seat with check function. Compared to the 025-A, the 025-B version is DIN flanged, not ANSI. The primary selection criterion is vertical installation with upward flow.

Installation and Maintenance

Installation should be free of mechanical stresses from piping, vibrations, and hydraulic shocks or sudden pressure surges. A special steel version is available, as well as a hollow ball with a 3 bar limit.

FAQ

Does it accept an actuator?
No. It is a passive flow indicator without an actuator.

Can it be installed in a horizontal line?
Not for typical ball operation. The technical sheet requires vertical installation with flow from bottom to top.