Chapter X - Special Flow Meters, Flow Gages, and Switches

Abstract

In different flow meters, various pick up types, such as magnetic, proximity, and Hall effect sensors are used so; the chapter starts with discussions of these pickups. During the discussions theory, features, applications, as well as a brief specification of each type are discussed at length. During the discussions, the design aspects of both analog and digital types of sensors and magnetic systems are covered in depth. Cryogenic liquids need special considerations for handling, especially for flow measurement. Special requirements for measuring systems, such as DP, Coriolis, vortex, turbine, ultrasonic, etc., in cryogenics are detailed. Different kinds of local flow monitors such as direct flow gages, sight flow indicator types, digital flow gages, water meters, and oil meters for both domestic and industrial applications are covered. Before discussions on flow switches, the basic requirements of flow and process switches in respect of set point/dead band adjustability, snap acting microswitches, reed contacts, NO NC contact meaning and contact configurations, contact rating, etc. are explained in detail. Starting with flow/no-flow paddle flow switches, various other kinds of flow switches, including vane type, variable-area type, and valve type flow switches for fluid applications are covered. For solid flow switching, microwave type, “triboflow” (electric charge) monitoring has been covered to complete the discussion.