Pennwalt Corporation

Elf Atochem North America, Inc.

John C Henry

Kyung T Park

Edward Tom

A device is disclosed for detecting the presence and direction of air flow through a passageway having a first opening and a second opening for air to flow therethrough in either a first direction or a second direction. The device comprises a piezoelectric sensor located within the passageway. A flow director is provided within the passageway for directing air flow through the passageway for impingement upon the sensor. The sensor generates a first electrical signal when air flows through the passageway in the first direction and a second electrical signal when air flows through the passageway in the second direction. A discriminator is electrically connected to the sensor for receiving the first and second electrical signals and for discriminating between the two signals to identify the direction of air flow through the passageway.

Device for detecting air flow through a passageway

A hail sensor is disclosed which contains a piezoelectric transducer positioned to produce an output signal when it is vibrated by a hailstone. In one embodiment, the transducer is mounted on a perforated member which is exposed to falling precipitation. In an alternative embodiment, the hailstone impacts a rebound surface and is deflected toward the transducer where an electrical output is produced.

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Upper Merion, PA, United States of America

John C Henry