Back to results
US 3,990,069 AGranted
System for monitoring changes in the fluidic impedance or volume of an enclosure
OwnerMark Schumaninventor
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
OwnerMark Schumaninventor
Estimating the term…
A monitoring system for detecting changes in the fluidic impedance of the boundary regions or volume of an enclosure, including detecting entry into, as well as certain movements within, a substantially sealed enclosure by means of synchronous detection of a modulated pressure signal within the enclosure. The air pressure within the enclosure is modulated at a predetermined amplitude and at a frequency which is sufficiently low to substantially avoid reverberation and wave interference effects, and means tuned to that frequency produce electrical signals indicative of the amplitude and phase, whereby entry into or exit from the enclosure, opening of a chamber within the enclosure, or blockage or unblockage of passageways within the enclosure vary the amplitude and/or phase of the modulated pressure, thereby causing an electrical signal to vary sufficiently to actuate an alarm.
In an enclosure having at least one boundary region defining at least one bounded region wherein any bounded region has a lower fluidic impedance than any of its boundary regions, a monitoring system for detecting a change in the fluidic impedance of at least one of said boundary regions or for detecting the movement of a portion of at least one of said boundary regions of said enclosure comprising means for inducing a predetermined substantially uniform variation in pressure with respect to time within at least one bounded region of said enclosure, means for monitoring deviation from said predetermined variation, wherein the induced pressure variation is spatially substantially uniform within any said bounded region of said enclosure at most given instants in time during monitoring.
In an enclosure having at least one boundary region defining at least one bounded region wherein said boundary regions provide significant impedance to fluid flow and are capable of supporting a significant differential pressure thereacross, a monitoring system for detecting a change in the fluidic impedance of at least one of said boundary regions or for detecting the movement of at least a portion of a boundary region, comprising means for inducing, with respect to time, a predetermined substantially uniform variation in the differential pressure across at least one boundary region of said enclosure, means for monitoring deviation from said predetermined variation, wherein the instantaneous induced pressure variation is spatially substantially uniform within any said bounded region of said enclosure at substantially any given instant in time during monitoring.
Dependencies are inferred from the claim text.