The Series UFB Ultrasonic Flowmeter Set utilizes the transit-time difference for measuring flow rates in pipes non-invasively. This is the permanent model, allowing the user to mount the converter on a surface or pipe. The easy-to-use compact and lightweight design is intended for mechanical devices using ideally homogeneous liquids that contain no air pockets. The Series UFB comes with a sturdy IP65 rating, protecting it from dust and direct water contact. The Series UFB has 4 to 20 mA and pulse output capabilities. PRINCIPLES OF OPERATION Two sensors are placed on the exterior of the pipe, and each transmits an ultrasonic pulse through the pipe and fluid to the other. The velocity of the liquid flowing through the pipes causes the pulse to accelerate or decelerate. The difference in the transit times of the two pulses is used to calculate the flow rate. The use of transit time allows the flowmeter to be unaffected by pressure or temperature changes.