Sight Flow Indicators - 881-K | Noris Armaturen

NORIS Model 881-K – Threaded Flow Indicator with Vane

The NORIS 881-K is a dual-sided flow indicator with BSP G or NPT threaded connections and an internal vane made of 1.4571. It is used for visual monitoring of liquids and gases in small pipelines where immediate flow presence indication is required without electrical signal or flow measurement.

Technical Specifications

• Connections: BSP G or NPT
• Sizes: 1/4" to 2"
• Operating Pressure: 16 / 25 / 40 bar
• Operating Temperature: up to 150 °C or 280 °C
• Installation: horizontal or vertical with upward flow
• Option: observation light
• Certificates: EN 10204 type 2.2 or 3.1 optional

Materials and Sealing

The body and covers are available in GG25 / EN-GJL-250, GS-C25 / 1.0619 / GP240GH, or stainless steel 1.4408. The GG25 version is limited to a maximum pressure of 16 bar. Glasses are borosilicate according to DIN 7080 for 280 °C or soda-lime according to DIN 8902 for 150 °C. Standard sealing is graphite, with other materials available after fluid and temperature assessment.

BSP or NPT Selection

NPT threading is available only in GS-C25 or 1.4408. This should be verified in projects with American piping specifications to avoid incorrect cast iron construction selection.

Difference from NORIS 881

The 881-K is the vane version. In clear fluids or low visual contrast, the vane allows easier flow confirmation than a simple dual-sided indicator. The basic 881 does not necessarily include an internal indication element.

Typical Applications

Suitable for auxiliary lines, process water, condensate, gases, small chemical lines, and circuits where local flow monitoring is required in a threaded connection.

FAQ

Does it accept an actuator?
No. It is a passive flow indicator.

What should be specified in the order?
Thread type, size, pressure, temperature, body material, glass type, gaskets, fluid, and need for observation light.