Single or multiple airflow elements are factory mounted and pre-piped in a casing designed for flanged connection to the duct work. Standard materials consist of a G90 galvanized casing and 6063-T5 anodized aluminum flow sensors, suitable for most HVAC applications.

The Series FLST utilizes an airflow averaging element in a head-type device, generating a differential (velocity) pressure signal similar to the orifice, venturi, and other had producing primary elements.

Strategically located sensing ports continually sample the total and static pressures when inserted normal to flow.

Total pressure sensed by the upstream ports are continually averaged within the airflow element in an isolated chamber. The static sensing ports are averaged in a second isolation chamber.

Multiple elements are joined together for connection to a differential measurement device (gauge, transmitter, etc.) for flow measurement and indication purposes.