The Model USP-30 Ultrasound Power Motor measures the average ultrasonic power by measuring the radiant force exerted by the transducer on the conical target.
This target is coupled to the precision mechanical balance that is used to measure the gram-mechanical force due to the ultrasonic radiation.
The gram force is directly proportional to the ultrasound power in watts when multiplied by a constant of 14.65. Therefore, a 2.05 gram force would be equal to 30 watts of ultrasound radiation. The heart of the USP-30 system is its air-filled conical target.
The weight of this target is nulled to a minimum by using its own buoyancy. Incident ultrasound energy is mechanically transferred from the target to the precision balance where it is manually measured.
Butyl rubber walls inside the water test tank absorb reflected ultrasound energy.
This system provides a sturdy instrument with good measurement accuracy and low cost.