Metal flow meter/switch for liquids from 0.1…1 to 10…250 l/min, with low sensitivity to dirt and up to 350 bar; bistable reed switch and ATEX/IECEx approvals.
Patented instrument for liquids that uses the float principle in a special design: instead of a tapered tube it has a cylindrical tube with conical slots around its circumference. The cylindrical float therefore does not have to be guided inside a cone, and the constant annular gap greatly reduces sensitivity to contamination. The body is brass or stainless steel, suitable for high pressures. ATEX, IECEx and CSA approved versions are available.
The medium lifts the float, which contains a permanent magnet. When the magnetic field reaches the externally mounted reed switch, the contact closes, so the medium stays fully separated from the electrical side. At higher flow rates the float rises to a mechanical stop that keeps it within the switching zone, so the contact remains closed (bistable switching). The reed switch sits in a height-adjustable housing that also protects it in aggressive atmospheres. In indicator versions the same magnetic field drives an external pointer, hermetically separated from the measuring circuit, which follows even sudden flow changes and allows use at high operating pressures.