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  1. SU Puresonic flowmeter
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Ultrasonic technology has no obstructions in pipe

Principle of operation

Ultrasonic flow meters consist of transducers that transmit and receive sound pulses. Medium on the opposite pipe wall diverts the direction of the transmitted pulse from one transducer to the other. A pulse is sent through the medium and the sensor measures the time of flight from one transducer to the other. Then a pulse is sent in the opposite direction. The meter measures the difference in time and calculates the flow rate. 

The internal pipe of the meter is constructed of only 316 stainless steel with no obstructions in the flow. There is a small reduction in sensing area through the sensor which leads to a minimal pressure drop.

Signal quality of application

Monitoring the conditions of the ultrasonic sensors signal strength indicates what is going on inside of your pipe system. As a result, possible maintenance measures can be taken at an early stage and machine downtimes can be minimized.

The unit detects the signal quality in three levels:

  • Normal: The unit works without restrictions.
  • Low: The signal quality is disturbed but the unit is still in specification. Check for air bubbles, particles or build-up.
  • No signal: No medium is present or no signal possible due to extreme conditions. 
    • Extreme conditions = excessive particles or bubbles, such as foam; and adhesions/ build-up on the internal pipe that strongly disrupt the signal.
LED Flow velocity Temperature Signal quality Output 1 (analog signal) Output 2 (diagnostic)
Green Normal On
Blue Low Off
Red x x No signal 21.5 mA or 3.5 mA Off

The signal quality is visible on the display of the unit or by the diagnostic LED color. Using conventional wiring, a switching output can be programmed to monitor a change in signal quality. Additionally, when using the unit's IO-Link capabilities, it is possible to distinguish between "low signal" and "no signal" because all events are output in detail.