Acoustic emission intrusion detector

Carver, Donald W; Whittaker, Jerry W

Title: Acoustic emission intrusion detector

Full Record
Other Related Research

Abstract

An intrusion detector is provided for detecting a forcible entry into a secured structure while minimizing false alarms. The detector uses a piezoelectric crystal transducer to sense acoustic emissions. The transducer output is amplified by a selectable gain amplifier to control the sensitivity. The rectified output of the amplifier is applied to a Schmitt trigger circuit having a preselected threshold level to provide amplitude discrimination. Timing circuitry is provided which is activated by successive pulses from the Schmitt trigger which lie within a selected time frame for frequency discrimination. Detected signals having proper amplitude and frequency trigger an alarm within the first complete cycle time of a detected acoustical disturbance signal.

Inventors:

Carver, Donald W ^[1]; Whittaker, Jerry W ^[1]

Knoxville, TN

Issue Date:: 1980-01-01

Research Org.:: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

OSTI Identifier:: 863549

Patent Number(s):: 4196423

Assignee:: United States of America as represented by United States (Washington, DC)

Patent Classifications (CPCs):: G - PHYSICS G08 - SIGNALLING G08B - SIGNALLING OR CALLING SYSTEMS

Show more

G - PHYSICS G08 - SIGNALLING G08B - SIGNALLING OR CALLING SYSTEMS
G08B13/1672 - {using sonic detecting means, e.g. a microphone operating in the audio frequency range}

Show less

DOE Contract Number:: W-7405-ENG-26

Resource Type:: Patent

Country of Publication:: United States

Language:: English

Subject:: acoustic; emission; intrusion; detector; provided; detecting; forcible; entry; secured; structure; minimizing; false; alarms; piezoelectric; crystal; transducer; sense; emissions; output; amplified; selectable; amplifier; control; sensitivity; rectified; applied; schmitt; trigger; circuit; preselected; threshold; level; provide; amplitude; discrimination; timing; circuitry; activated; successive; pulses; lie; selected; time; frame; frequency; detected; signals; proper; alarm; complete; cycle; acoustical; disturbance; signal; trigger circuit; selected time; false alarms; threshold level; timing circuit; time frame; acoustic emission; acoustic emissions; detected signal; piezoelectric crystal; successive pulses; detected signals; complete cycle; selected threshold; intrusion detector; cycle time; /340/307/324/

Citation Formats


                    Carver, Donald W, and Whittaker, Jerry W. Acoustic emission intrusion detector.  United States: N. p., 1980. 
        Web.

Copy to clipboard


                    Carver, Donald W, & Whittaker, Jerry W. Acoustic emission intrusion detector.  United States.

Copy to clipboard


                    Carver, Donald W, and Whittaker, Jerry W. Tue .  
        "Acoustic emission intrusion detector".  United States.  https://www.osti.gov/servlets/purl/863549.

Copy to clipboard


                    
@article{osti_863549,

  title        = {Acoustic emission intrusion detector},

  author       = {Carver, Donald W and Whittaker, Jerry W},

  abstractNote = {An intrusion detector is provided for detecting a forcible entry into a secured structure while minimizing false alarms. The detector uses a piezoelectric crystal transducer to sense acoustic emissions. The transducer output is amplified by a selectable gain amplifier to control the sensitivity. The rectified output of the amplifier is applied to a Schmitt trigger circuit having a preselected threshold level to provide amplitude discrimination. Timing circuitry is provided which is activated by successive pulses from the Schmitt trigger which lie within a selected time frame for frequency discrimination. Detected signals having proper amplitude and frequency trigger an alarm within the first complete cycle time of a detected acoustical disturbance signal.},

  doi          = {},

  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {1980},

  month        = {1}

}

Copy to clipboard

Patent:

Save / Share:

Export Metadata

Save to My Library

Similar Records in DOE Patents and OSTI.GOV collections:

Non-intrusive ultrasonic liquid-in-line detector for small diameter tubes

Patent Piper, Thomas C [Idaho Falls, ID]

An arrangement for deleting liquid in a line, using non-intrusive ultrasonic techniques is disclosed. In this arrangement, four piezoelectric crystals are arranged in pairs about a 0.072 inch o.d. pipe. An ultrasonic tone burst is transmitted along the pipe, between crystal pairs, and the amplitude of the received tone burst indicates the absence/presence of liquid in the pipe.
Full Text Available
Seismic intrusion detector system

Patent Hawk, Hervey L [Albuquerque, NM]; Hawley, James G [Albuquerque, NM]; Portlock, John M [Albuquerque, NM]; ...

A system for monitoring man-associated seismic movements within a control area including a geophone for generating an electrical signal in response to seismic movement, a bandpass amplifier and threshold detector for eliminating unwanted signals, pulse counting system for counting and storing the number of seismic movements within the area, and a monitoring system operable on command having a variable frequency oscillator generating an audio frequency signal proportional to the number of said seismic movements.
Full Text Available
Resonant surface acoustic wave chemical detector

Patent Brocato, Robert W.; Brocato, Terisse; Stotts, Larry G.

Apparatus for chemical detection includes a pair of interdigitated transducers (IDTs) formed on a piezoelectric substrate. The apparatus includes a layer of adsorptive material deposited on a surface of the piezoelectric substrate between the IDTs, where each IDT is conformed, and is dimensioned in relation to an operating frequency and an acoustic velocity of the piezoelectric substrate, so as to function as a single-phase uni-directional transducer (SPUDT) at the operating frequency. Additionally, the apparatus includes the pair of IDTs is spaced apart along a propagation axis and mutually aligned relative to said propagation axis so as to define an acousticmore » « less
Full Text Available
Acoustic sand detector for fluid flowstreams

Patent Beattie, Alan G [Corrales, NM]; Bohon, W Mark [Frisco, TX]

The particle volume and particle mass production rate of particulate solids entrained in fluid flowstreams such as formation sand or fracture proppant entrained in oil and gas production flowstreams is determined by a system having a metal probe interposed in a flow conduit for transmitting acoustic emissions created by particles impacting the probe to a sensor and signal processing circuit which produces discrete signals related to the impact of each of the particles striking the probe. The volume or mass flow rate of particulates is determined from making an initial particle size distribution and particle energy distribution and comparing themore » « less
Full Text Available
Acoustic emission linear pulse holography

Patent Collins, H Dale [Richland, WA]; Busse, Lawrence J [Richland, WA]; Lemon, Douglas K [West Richland, WA]

Defects in a structure are imaged as they propagate, using their emitted acoustic energy as a monitored source. Short bursts of acoustic energy propagate through the structure to a discrete element receiver array. A reference timing transducer located between the array and the inspection zone initiates a series of time-of-flight measurements. A resulting series of time-of-flight measurements are then treated as aperture data and are transferred to a computer for reconstruction of a synthetic linear holographic image. The images can be displayed and stored as a record of defect growth.
Full Text Available

Similar Records