Abstract: In semiconductor manufacture requiring ultra high purity water, particles of specified sizes are detected using acoustic particle detection capable of detecting nanoparticles. A sensor unit receives a flow of water, with the pressure and rate of flow to the sensor controlled closely. In each sensor unit is a measurement cell to receive a continuous flow of water, with a transducer module engaged with the cell to deliver an acoustic pulse at a known level of intensity as the liquid flows through the cells, the acoustic pulse acting on the liquid at a focus zone to cause cavitation in the event a particle of size detectable at that intensity is present. A waveform emitter/receiver connected to the sensor unit sends high-frequency, high-voltage signal to the transducer module to cause the acoustic pulse, and it also receives a waveform echo indicating a cavitation event. The system is controlled by a microprocessor.

Abstract: The invention relates to a supply device (1, 51, 81, 101) for supplying breathable air to a breathable air region (2, 52, 82) which is at least partially open to the surroundings. Said supply device comprises means for generating a flow of air (3, 53, 83) for supplying breathable air to the breathable air region (2, 52, 82). Said supply device (1, 51, 81, 101) also comprises means for generating at least one shielding air flow (4, 5, 54, 84) which shields the breathable air flow (2, 52, 82) at least partially with respect to the surroundings.