Water-resistant transducer housing with hydrophobic vent

摘要

An immersion-resistant housing adapted to receive a vibratable diaphragm spanning the interior of the housing to divide the housing into first and second chambers includes a first port communicating between the first chamber and the exterior environment. The first port is configured as a tubulation. A second port communicates between the second chamber and the external environment. The tubulation has sufficiently small diameter that water entering therein moves essentially as a piston without breakup. The tubulation is configured to have a volume at least equal to that of the first chamber, and a hydrostatic head of about 32 feet of water is necessary before water can be forced into the first chamber. In the preferred embodiment the diaphragm completely seals the housing against direct communication between the two chambers. Pressure equalization across the diaphragm under conditions of varying atmospheric pressure is achieved by a selective sealing system permitting passage of air through the second port while preventing the passage of water therethrough at pressures up to at least three and preferably ten meters of hydrostatic head.