# Measurement Principle and Design Applications
This product incorporates technologies protected by multiple international patents.
The LORRIC clamp-on ultrasonic flowmeter uses the **Time of Flight (ToF)** principle, measuring the travel time difference of ultrasonic waves upstream and downstream to calculate flow rate.
Its **integrated clamp-on design** allows installation **without system shutdown**, avoids pipe damage, and provides **excellent chemical resistance and leak protection**. Unlike conventional clamp-on meters, **no probe distance calibration is required**, reducing installation time and training requirements.
Due to pipeline dimensional tolerances, the system may show **small flow readings even when no fluid is moving**. This is normal and caused by physical measurement characteristics.
{% hint style="info" %}
Avoid fluids with large amounts of solids, bubbles, crystals, or sediment, which may interfere with ultrasonic measurement.
Install the unit away from strong magnetic fields or electromagnetic interference.
Ensure the fluid is in **fully developed flow** for accurate measurement. Follow installation guidelines for proper placement.
{% endhint %}
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