EMCO's model Vortex PhD™ is an inline vortex shedding flowmeter capable of measuring liquids or gases including steam, for pipe sizes from 0.5" to 12", available in stainless steel, carbon steel and Haselloy^®.  The PhD has no moving parts, rugged construction, and microprocessor based electronics for high accuracy in many flowmetering applications. The Vortex PhD with no moving parts provides accurate measurement with lower maintenance, and lower total cost of ownership than other flowmeter technologies.

Vortex shedding is a physical phenomenon occurring in nature.  As flow passes a bluff body in the flow stream, vortices are alternately shed on either side of the bluff body.  This effect can be observed in the fluttering of a flag.  The flag pole acts as a bluff body to the wind.  The flag waves in response to the vortices shed as the wind passes the flag pole.  According to well proven physical laws, the frequency at which vortices are alternately shed is directly proportional to the flow velocity.

The vortices create low and high pressure zones behind the bluff body.  the vortex PhD uses a piezoelectric crystal sensor to detect the pressure exerted by the vortices on the sensing wing.  The piezoelectric crystal converts this vortex shedding frequecy into electrical signals.  The piezoelectric crystal is mounted outside the flow line to permit easy removal and replacement under full flow conditions, without process shutdown or risk of exposure to hazardous fluids.

The "Smart", microprocessor-based electronics translates the electrical signals (flow velocity) into a flow rate based on user-selected engineering units.  The 8-character, 2-line, local display alternates between flow rates and totalized flow.  Either a 4-20 mA current, analog or frequency, pulse output communicates to user equipment.