Variable area flowmeters are simple and versatile devices that operate at a relatively constant pressure drop and measure the flow of liquids, gases, and steam. Variable Area (VA) flowmeters make use of a float, piston or vane placed inside a flow body, which changes position in response to changes in flow rate of the measure fluid media. The position of the float, piston or vane provides a direct visual indication of flow rate. Either the force of gravity or a spring is used to return the float to its resting position when the flow lessens.  For a more detailed discussion of the principle of operation, please go to: http://www.smartmeasurement.com/flow-meters/variable-area/measuring-principle

Smartmeasurement^TM’ s ALVAMT Variable Area flow meter is of the spring operated variety, which allows the meter to be mounted in either horizontal or vertical orientations. The ALVAMT makes use of rugged, metal tube construction making it ideal for high pressure, high temperature and other demanding flow applications where safety is a concern.  Features include mechanical readouts for use in locations where power is not available or in hazardous areas; analog and digital LCD local display options, multiple process connection options; several different materials of construction for metering of aggressive fluids and corrosion resistance; and HART enabled 4-20mA output to allow for remote monitoring and control.


Metal Tube Variable Area Meter

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Technology	Model/ Series	Gas Flow	Liquid Flow	Steam Flow	Line Size	Temperature	Pressure	Viscosity	Accuracy	Considerations
Variable Area	ALVAMT									Liquids must be clean

 

Variable Area Flow Meters

 

ALVA Family
Technology	Model	Line Sizes	Flow Rate	Viscosity	Accuracy	Pressures	Temperature	Materials	Mounting Orientations	Outputs
Metal Tube	ALVAMT	½"-8" (8 - 400mm)	0.01-660 GPM (0.05 - 2,500 LPM)	1～300 cP	±1.5% (Std), ±2.5% w/ PTFE materials	930 psig (64 barg)	575 °F (300 °C) max	304SS (Std); 316SS, PTFE, or Tantalum (Opt)	Horizontal or vertical	Analog 4-20 mA, 0-5 VDC, HART, swtch & open collector
Glass Tube	Not Available From SMC	¼" - 3" (6 - 80mm)	0.05 to 264 GPM (0.005 to 1000 LPM)	< 50 cP recommended	±0.50% ~ ±5.0 of reading depending on make & model	<100 psig (7 barg)	Up to 350 °F (180 °C) max. depending on make & model	Borosilicate, acrylic, or polycarbonate tube, Stainless Steel float, depends on make & model	Vertical only	Switch & open collector