Alternate vortices rotating in opposite directions are generated behind a bluff body immersed in a flow. The vortices detach from the edges of the bluff body and form a Kármán vortex street in the fluid stream. The distance between the single vortices is constant. The frequency of the vortices flowing past a sensor depends on the flow rate and is proportional to the flow. The sensor detects these vortices which are then converted to an electrical frequency signal.     
Some of the advantages of this measuring principle:

Available in nominal pipe sizes DN15, 20, 25, 32, 40. Multi-sensor for flow and temperature.

The advantages at a glance:

• Robust and durable: A complete series made of stainless steel
• Digital: Utilisation of the LIN bus digital communication system
• A tradition of quality: SIKA is recognised as one of the market leaders
• Extensive approvals: USANPT-approved & ETL/UL-approved, among others
• Capacity on demand: Thanks to production capacity, requirements can be met quickly
• Optimum turn-down ratio: Measuring span Tp 1:32