Security alarm process and apparatus
First Claim
1. 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.
1 Assignment
0 Petitions
Accused Products
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.
25 Citations
24 Claims
-
1. 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. 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. - View Dependent Claims (10)
-
-
11. 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. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 24)
-
-
21. 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. - View Dependent Claims (22, 23)
-
Specification