Flow Sensors

NOS Hemispheric and Ballhead Sensor

Part No. NOS-VX0B

For measurement places with various geometries

For connection to NivuFlow 650 transmitters. High accurate flow measurement based on the transit time method for open channels and waters, mainly process water channels and natural water bodies.

  • <link https: www.nivus.com en service-download know-how laufzeitdifferenz external-link-new-window>Ultrasonic transit time sensor for connection to NivuFlow 650
  • Hydrometry with highest measurement accuracy
  • Measurement in clear to slightly polluted water
  • For 8-path measurements according to IEC 60041 (ASME PTC 18)
  • Measurement in open channels and surface water bodies
  • Resistant sensor material for use in various media
  • Up to 100 m of cable length between sensor and transmitter or adapter box

NOS hemispheric and ballhead sensors are part of a fixed measurement system for continuous flow measurement and storage of the recorded measurement data. They can be used for clean to slightly polluted media in part filled and full flumes as well as channels featuring various geometries and dimensions.

Typical NOS hemispheric and ballhead sensor applications


  • Fixed measurement of surface water bodies such as rivers, channels and similar
  • Irrigation systems 
  • Inlets and outlets conducting cooling water or circulation systems 
  • WWTP outlets
  • Investigation of infiltration/extraneous water or leakage
  • Industrial flow measurements
  • and many more



Measurement principle Ultrasonic transit time method
Measurement uncertainty flow velocity (v average) ± 0.1 % of measurement uncertainty value within the path
Offset velocity < ± 5 mm/s
Measurement frequency 1 MHz, 200 kHz, and or 500 kHz
Protection IP68
Operating temperature -20 °C to +50 °C
Storage temperature -30 °C to + 70 °C
Operating pressure max. 1 bar
Cable lengths 10/15/20/30/50/100 m pre-configured, with underwater plug to facilitate Installation
Extension option: Sensors can be connected to Extension modules NFE, cable length between NFE and Transmitter max. 200 m
Weight (sensor head) approx. 1000 g
Medium-contacting materials Hemisphere sensor: stainless steel 1.4571, CFK (Carbon), POM, PUR, underwater plug and socket made of Neoprene

Specifications subject to change.

Technical Description "Transit Time Sensors Rev. 05"

Mounting Instruction Rev.04 "Transit Time Sensors"

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