Cooling fluid monitoring device - designed esp. for air stream in electronic equipment cooling system

摘要

A flowmeter is provided, delivering a warning signal when the air flow falls below a value necessary for satisfactory cooling. The flowmeter has a fan wheel (11) driven by the cooling air stream, which in turn drives a pulse generator generating an adjustable number of pulses per fan wheel revolution. A pulse evaluating device measures spacings between pulses, and when they exceed a specified time interval, it generates the alarm signal. The output of the Schmitt trigger (ST) is connected to the input of a first scanning stage (FF1). Control pulses are conducted to another input of this first stage via a regulating potentiometer (P1).