Compact variable area flow switch for liquids with conical restriction

Flow switch for liquids based on the float principle, but built differently from the classic tapered tube: a cylindrical float works against a conical restriction inside the tube. This design keeps the unit very compact and cost-effective. The body is available in brass or stainless steel, with female G or NPT threaded connections.

Features

• Set point ranges from 0.05…1 l/min up to 10…110 l/min of water
• G ¼…G 1¼ or ¼…1¼" NPT female connections
• Maximum pressure 250 bar (brass) or 350 bar (stainless steel)
• Maximum temperature 100 °C
• Accuracy ±5 % of full scale
• ATEX, IECEx and CSA approvals

Operating principle

Instead of a tapered metering tube, the instrument uses a cylindrical float moving relative to a cone-shaped restriction housed in the tube. The flow area changes with the float position, as in a conventional rotameter, but in a far more compact construction.