Sammlung:Variable area flow meters

Variable area flow meters show the flow of a liquid on a scale. A spring-loaded float moves with the flow, so the reading needs no power supply and no wiring and is visible at a glance. Choose the body material first: it sets the pressure rating and the liquids the meter suits. Plastic variable area flow meters up to 16 bar (≈230 psi) have a transparent body and a scale for one medium: water, or oil of one viscosity. They suit low-pressure lines and tolerate lightly contaminated liquids. An oil that is thicker than the scale medium gives a reading error.

Metal variable area flow meters up to 300 bar (≈4350 psi) have a brass or stainless steel body for oil lines at high pressure; versions with switch contact go up to 350 bar (≈5080 psi). Viscosity compensation keeps one scale valid over a wide range, up to 600 cSt (centistokes) for most models, so a change of oil needs no new scale. They need oil without solid or magnetic particles.

For a reading and a switching signal in one device, choose a metal variable area flow meter with switch contact. For a switching signal only, choose a metal variable area flow switch.