Sprinkler alarm
First Claim
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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Accused Products
Abstract
An acoustic sensor and associated electronic circuitry are used to determine when a catastrophic leak (as e.g. may be caused by a sprinkler nozzle being broken off a pipe) occurs in a sprinkling system. When a catastrophic leak is detected, an alarm signal is generated and a shutoff valve may be actuated in order to prevent loss of fluid and possible damage that can occur due to localized high flow of the fluid that is being sprayed. The acoustic sensor responds to a frequency range of acoustic signals that encompasses the generally low frequency signals generated by the relatively unconstrained flow of fluid through a pipe, as well as the higher frequency signals generated by flow of fluid through one or more nozzles. Electronic signal processing means are employed to form a ratio of the acoustic power in two different frequency regions and to generate an alarm signal when flow generates an excess of low frequency acoustic power.
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Citations
14 Claims
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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:
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an acoustic transducer placed in acoustic contact with the pipe proximal to said valve; signal processing means comprising amplification 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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Method of 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:
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detecting an acoustic signal with an acoustic transducer placed in acoustic contact with the pipe proximal to said control valve; processing said acoustic signal to derive both an index of the acoustic power at frequencies below a first predetermined frequency, and an index of the acoustic power at frequencies above a second predetermined frequency; calculating 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 generating an alarm signal if said ratio exceeds a predetermined value. - View Dependent Claims (8, 9, 10)
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11. A system 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:
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an acoustic transducer placed in acoustic contact with said pipe proximal to said valve and suitable to provide an electronic representation of the acoustic power spectrum in said pipe; signal processing means suitable to amplify the output of said acoustic transducer, and to determine the ratio of the acoustic power at frequencies below a first predetermined frequency to the acoustic power at frequencies above a second predetermined frequency and to generate an alarm signal if said ratio exceeds a predetermined value. - View Dependent Claims (12, 13, 14)
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Specification