OPERATING PRINCIPLE
The EZ-View Flow Meter is a variable-area instrument. A precisionmolded, sharp-edged Orifice, located within the Piston Assembly, forms an annular opening with the Metering Cone. Flow through the meter creates a pressure differential across the sharp-edged orifice, moving the piston against the Spring. The piston moves precisely, in direct proportion to the rate of flow. The calibrated spring opposes flow in the forward direction. This spring decreases viscosity sensitivity and allows the flow meters to be used in any position.  The indicated flow rate is measured by viewing the red indicator line on the piston relative to the precalibrated numerical scale, mounted on the outer surface of the transparent flow meter body.
Operates in any position: The Hedland In-line flow meter’s unique spring loaded variable-area design allows meters to be installed in any position without affecting accuracy. It can be installed into horizontal or vertical lines, or with an optional inverted flow scale, this meter can monitor flow in a downward flowing (i.e. gravity feed) line. Easy-to-read scale: This flow meter is the most readable product in its class. A brightly colored flow scale contains bold, easy-to-read numerals and gauge marks. This enhanced resolution virtually eliminates parallax problems associated with competitive, direct
reading flow meters.

Accuracy within ±5% full scale: The EZ-View Flow Meter accuracy is within ±5% of full scale while monitoring liquids and gases with viscosity and specific gravity similar to factory calibrated fluids.
Repeatability within ±1%: This is particularly important in cyclical
applications, which require consistent readings.
Operating temperature: Maximum operating temperature is 250 °F (121 °C)
Operating pressure: Liquid: Maximum operating pressure is 325 psi/22.4 bar. Air/Gases: Maximum operating pressure is 125 psi/8.6 bar.
Rugged construction: Flow meters are available with  brass fittings,  (see ordering information table). Constructed of high-impact polysulfone plastic, this simple variable-area flow meter contains a minimum number of moving parts, offering you a reliable, trouble-free flow rate indicator to monitor a wide range of liquids and gases.
Note: Inlet and outlet pipe supports are recommended to prevent breakage.

MATERIALS:
Polysulfone plastic body, piston and cone
T300-series stainless spring
Buna N flow indicator ring and presure seals
C360 Brass, fittings
Polupropylene limit indicators
PH 15 – 7 MO stainless steel retaining ring