US4853690A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Security alarm process and apparatus
Assignee: Richard Hirschmann Radiotechnisches Werk
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Filing: 1987-04-01
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Granted: 1989-08-01
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Expires: 2007-04-01
Abstract
Abstract Monitoring a room is accomplished by measurement of air pressure where air passage resistance between a secured room and an outside atmosphere is measured and an alarm actuated, if the air passage resistance drops below a predetermined value. Evaluation of typical air pressure fluctuations in a frequency range between 0.01 Hz and 10 Hz is advantageous. The air pressure resistance may be determined by difference measurements of air pressure fluctuations in the outside atmosphere and the secured room, or as a singular process wherein a connecting tube is provided between the room to be secured and the outside atmosphere, where air movements varying as a function of air pressure fluctuations are measured. Devices for the carrying out of the process are described. The devices and the process provide a simple and cost effective alarm system that operates reliably and is secure against outwitting and sabotage.
Inventors
- 👤 Hans-Dieter Mayer
- 👤 Klaus Hirrlinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:23
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/20
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
74 words
A method of securing an enclosed area comprising the steps of: monitoring air passage resistance of an enclosed area; and actuating an alarm when air passage resistance falls below a predetermined level; wherein the step of monitoring includes the steps of measuring air pressure in said enclosed area, measuring air pressure outside of said enclosed area, and evaluating the difference between air pressure in the enclosed area and air pressure outside the enclosed area.
Claim 2
Independent Claim
74 words
A method of securing an enclosed area comprising the steps of: monitoring air passage resistance of an enclosed area; and actuating an alarm when air passage resistance falls below a predetermined level; wherein the step of monitoring includes the steps of measuring air pressure in said enclosed area, measuring air pressure outside of said enclosed area, and evaluating the difference between air pressure in the enclosed area and air pressure outside the enclosed area.
Claim 3
Dependent Claim
24 words
A method according to claim 1 further comprising the step of: actuating an alarm when air passage resistance rises above a second predetermined level.
Claim 4
Dependent Claim
22 words
A method according to claim 1 wherein the step of monitoring comprises monitoring air pressure fluctuations between 0.01 Hz and 10 Hz.
Claim 5
Dependent Claim
22 words
A method according to claim 3 wherein the step of monitoring comprises monitoring air pressure fluctuations between 0.1 Hz and 5 Hz.
Claim 6
Dependent Claim
20 words
A method according to claim 1 wherein the step of evaluating comprises evaluating an amplitude difference between measured air pressures.
Claim 7
Dependent Claim
20 words
A method according to claim 1 wherein the step of evaluating comprises evaluating a phase difference between measured air pressures.
Claim 8
Dependent Claim
24 words
A method according to claim 1 wherein the steps of measuring comprise measuring air pressure by evaluating air movements caused by air pressure fluctuations.
Claim 9
Dependent Claim
35 words
A method according to claim 7 wherein the steps of measuring comprise the steps of: heating a bolometer arranged in a orifice of a rigid hollow body; and evaluating temperature changes characteristic of pressure changes.
Claim 10
Independent Claim
82 words
A method of securing an enclosed area comprising the steps of: monitoring air passage resistance of an enclosed area by measuring air movements through a connecting tube arranged in a wall of said enclosed area, between said enclosed area and outside said enclosed area; actuating an alarm when air passage resistance falls below a predetermined level; generating air pressure pulses inside said enclosed area; and evaluating measured air movements through said connecting tube in relation to generation of said air pressure pulses.
Claim 11
Independent Claim
82 words
A method of securing an enclosed area comprising the steps of: monitoring air passage resistance of an enclosed area by measuring air movements through a connecting tube arranged in a wall of said enclosed area, between said enclosed area and outside said enclosed area; actuating an alarm when air passage resistance falls below a predetermined level; generating air pressure pulses inside said enclosed area; and evaluating measured air movements through said connecting tube in relation to generation of said air pressure pulses.
Claim 12
Dependent Claim
31 words
A method according to claim 9 wherein the step of monitoring comprises the steps of: heating a bolometer arranged in said connecting tube; and evaluating temperature changes characteristic of pressure changes.
Claim 13
Independent Claim
87 words
A device for securing an enclosed area comprising: means for monitoring air passage resistance of an enclosed area; and means for actuating an alarm when air passage resistance falls below a predetermined level responsive to said means for monitoring wherein said means for monitoring includes a first means for measuring air pressure in said enclosed area, a second means for measuring air pressure outside of said enclosed area, and a means for evaluating a difference in air pressure responsive to said first and second means for measuring.
Claim 14
Independent Claim
87 words
A device for securing an enclosed area comprising: means for monitoring air passage resistance of an enclosed area; and means for actuating an alarm when air passage resistance falls below a predetermined level responsive to said means for monitoring wherein said means for monitoring includes a first means for measuring air pressure in said enclosed area, a second means for measuring air pressure outside of said enclosed area, and a means for evaluating a difference in air pressure responsive to said first and second means for measuring.
Claim 15
Dependent Claim
29 words
A device according to claim 11 further comprising: means for actuating an alarm when air passage resistance rises above a second predetermined level responsive to said means for monitoring.
Claim 16
Dependent Claim
24 words
A device according to claim 11 wherein said means for monitoring comprises means for monitoring air pressure fluctuations between 0.01 Hz and 10 Hz.
Claim 17
Dependent Claim
24 words
A device according to claim 13 wherein said means for monitoring comprises means for monitoring air pressure fluctuations between 0.1 Hz and 5 Hz.
Claim 18
Dependent Claim
22 words
A device according to claim 11 wherein said means for evaluating comprises means for evaluating an amplitude difference between measured air pressures.
Claim 19
Dependent Claim
22 words
A device according to claim 11 wherein said means for evaluating comprises means for evaluating a phase difference between measured air pressures.
Claim 20
Dependent Claim
17 words
A device according to claim 11 wherein said means for measuring comprise means for measuring air movements.
Claim 21
Dependent Claim
29 words
A device according to claim 17 wherein said means for measuring comprises: a rigid hollow body exhibiting a small orifice; and a bolometer arranged in said rigid hollow body.
Claim 22
Dependent Claim
20 words
A device according to claim 18 wherein said hollow body has a volume of at least 500 cm 3 .
Claim 23
Dependent Claim
28 words
A device according to claim 18 wherein the means for measuring further comprises: means for heating said bolometer; and means for evaluating temperature changes characteristic of pressure changes.
Claim 24
Independent Claim
79 words
A device for securing an enclosed area comprising: a connecting tube arranged in a wall of said enclosed area; means for monitoring air passage resistance of an enclosed area by measuring air movements through said connecting tube; means for generating air pressure pulses arranged inside said enclosed area; and means for evaluating measured air movements through said connecting tube in relation to generation of said air pressure pulses responsive to said means for generating and said means for monitoring.
Claim 25
Independent Claim
79 words
A device for securing an enclosed area comprising: a connecting tube arranged in a wall of said enclosed area; means for monitoring air passage resistance of an enclosed area by measuring air movements through said connecting tube; means for generating air pressure pulses arranged inside said enclosed area; and means for evaluating measured air movements through said connecting tube in relation to generation of said air pressure pulses responsive to said means for generating and said means for monitoring.
Claim 26
Dependent Claim
19 words
A device according to claim 21 wherein said means for monitoring comprises a bolometer arranged inside said connecting tube.
Claim 27
Dependent Claim
27 words
A device according to claim 22 wherein said means for monitoring further comprises: means for heating said bolometer; and means for evaluating temperature changes of said bolometer.
Claim 28
Dependent Claim
16 words
A device according to claim 20 wherein said bolometer is a small heat capacity semiconductor bolometer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-31 | 1993-01-30 | 1993-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-31 | 1997-01-30 | 1997-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-31 | 2001-01-30 | 2001-08-01 | $7700.00 | Window Closed / Lapsed |