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Sprinkler alarm

  • US 5,040,409 A
  • Filed: 04/04/1990
  • Issued: 08/20/1991
  • Est. Priority Date: 04/04/1990
  • Status: Expired due to Fees
First Claim
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1. Apparatus for detecting a broken pipe in a sprinkler system comprising a source of fluid under pressure to be sprinkled, at least one pipe to transport said fluid, at least one valve for controlling flow in said pipe, and at least one sprinkler head, comprising:

  • an acoustic transducer placed in acoustic contact with the pipe proximal to said valve;

    signal processing means comprisingamplification means to amplify the output of said acoustic transducer,low-pass filter means attached to the output of said amplification means,first signal conditioning means attached to the output of said low pass filter means to derive an index of the acoustic power at frequencies below a first predetermined frequency,high-pass filter means, attached to the output of said amplification means,second signal conditioning means attached to the output of said high pass filter means to derive an index of the acoustic power at frequencies above a second predetermined frequency;

    electronic logic circuit means to calculate the ratio of said index of acoustic power at frequencies below said first predetermined frequency to said index of acoustic power above said second predetermined frequency and to generate an alarm signal if said ratio exceeds a predetermined value.

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