What Is A Venturi Flow Meter?

In order for hydronic systems in HVAC layouts to function properly, they need to be balanced for equal water flow distribution.  Imbalanced water pressure in the system result in uneven and inconsistent water and air temperatures throughout the building, much like poor cardiac circulation can leave your hands and feet cold.  In order to maintain pressure balance, calibrated measuring devices need to be installed throughout the hydronic circuit system.

A venturi flow meter is used to measure the differential pressure, or the difference in the flow rate at the widest point and the narrowest point of the conical-shaped tube.  Differential pressure gauges are used to measure the rate of flow between the two pressure taps in the venturi meter.  Because the venturi flow meter has less head loss, it has an advantage over other measuring devices like orifice plates and nozzles.  Some brands of balancing valves conveniently come with the venturi design and meter built in them, like Flo-Pac's manual balancing valves.