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US 5,703,836 AGranted
Acoustic transducer
AssigneeSandia Corporation
InventorDouglas S. Drumheller
Life of this patent
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AssigneeSandia Corporation
InventorDouglas S. Drumheller
Estimating the term…
An acoustic transducer comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers.
An active acoustic transducer comprising a one-piece hollow mandrel in the form of a modified cylinder that is symmetric about a central axis into the outer surface of which mandrel is formed a recess with sides perpendicular to the central axis, said sides being separated by a first distance, and with a bottom parallel to the central axis and at a constant radial distance therefrom and within which recess are a plurality of segmented washer-shaped discs of a piezoelectric material, the washer-shaped discs having an inner radius slightly larger than the constant radial distance of the bottom of the recess and an outer radius slightly less than the top of the sides of the recess with the plurality of discs being captured between the sides of the recess in a pre-stressed interference fit.
An active acoustic transducer comprising a one-piece hollow mandrel in the form of a modified cylinder that is symmetric about a central axis into the outer surface of which mandrel is formed a recess with sides perpendicular to the central axis, said sides being separated by a first distance, and with a bottom parallel to the central axis and at a constant radial distance therefrom and within which recess are a plurality of segmented washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material, the discs having an inner radius slightly larger than the constant radial distance of the bottom of the recess and an outer radius slightly less than the top of the sides of the recess with the discs being captured between the sides of the recess in a pre-stressed interference fit, the transducer further including a power supply electrically connected to the plurality of discs of the piezoelectric material.
Dependencies are inferred from the claim text.