Alarm with CO and smoke sensors

• US 20080211678A1
• Filed: 03/02/2007
• Published: 09/04/2008
• Est. Priority Date: 03/02/2007
• Status: Active Grant

• Current Assignee: Walter Kidde Portable Equipment Incorporated (Carrier Global Corporation)
• Original Assignee: Walter Kidde Portable Equipment Incorporated (Carrier Global Corporation)
• Inventors: Burnette, Stanley D., Andres, John J., Bush, David A.
• Granted Patent: US 7,642,924 B2
• Time in Patent Office: Days
• US Class Current: 340/603
• CPC Class Codes: G08B 17/00 Fire alarms; Alarms responsive to explosion
• CPC Class Codes: G08B 29/183 Single detectors using dual technologies G08B13/1672, G08B13/2448, G08B13/2494 take precedence

Abstract

A life safety device includes a smoke sensor and a carbon monoxide (CO) sensor. Smoke sensitivity of the device is adaptively adjusted based upon the smoke sensor signal and the CO sensor signal.

Claims

1. A life safety device comprising:

a smoke sensor for producing a smoke sensor signal;

a carbon monoxide (CO) sensor for producing a CO sensor signal;

a controller for controlling generation of a smoke alarm based upon the smoke sensor signal and the CO sensor signal, the controller adaptively adjusting sensitivity to the smoke sensor signal as a function of the smoke sensor signal and the CO sensor signal.

2. The life safety device of claim 1, wherein the controller decreases sensitivity to the smoke sensor signal when the smoke sensor signal reaches an initial smoke threshold.

3. The life safety device of claim 2, wherein the controller causes a smoke alarm to be generated if the smoke sensor signal reaches a decreased sensitivity threshold.

4. The life safety device of claim 2, wherein the controller causes a smoke alarm to be generated if the smoke sensor signal is at or beyond the initial smoke threshold at expiration of a timeout period.

5. The life safety device of claim 2, wherein the controller causes a smoke alarm to be generated if, after sensitivity to the smoke sensor signal is decreased, the CO sensor signal reaches a CO/smoke threshold.

6. The life safety device of claim 1, wherein the controller increases sensitivity to the smoke sensor signal if the CO sensor signal reaches a CO/smoke threshold before the smoke sensor signal reaches an initial smoke threshold.

7. The life safety device of claim 6, wherein the controller causes a smoke alarm to be generated if, after sensitivity to the smoke sensor signal is increased, the smoke sensor signal reaches an increased sensitivity threshold.

8. The device of claim 1, where the controller enters a Smart Hush state when the smoke sensor signal reaches an initial smoke threshold, in which the controller causes a smoke alarm to be generated if (a) the CO sensor signal reaches a CO/smoke threshold, (b) the smoke sensor signal reaches an adjusted smoke threshold, or (c) the smoke sensor signal has reached the initial smoke threshold at an end of a timeout period.

9. A method of detecting fires, the method comprising:

comparing a smoke sensor signal to a smoke alarm threshold;

comparing a carbon monoxide (CO) sensor signal to a CO/smoke threshold;

adjusting the smoke alarm threshold based upon the smoke sensor signal and the CO sensor signal; and

generating a smoke alarm based upon the smoke sensor signal and the adjusted smoke alarm threshold.

10. The method of claim 9, wherein adjusting the smoke alarm threshold comprises:

adjusting the smoke alarm threshold to decrease sensitivity to smoke if the smoke sensor signal reaches an initial smoke alarm threshold.

11. The method of claim 10, wherein generating a smoke alarm comprises:

generating a smoke alarm if the CO sensor signal reaches the CO/smoke threshold or the smoke sensor signal reaches the smoke alarm threshold as adjusted to decrease sensitivity.

12. The method of claim 9, wherein adjusting the smoke alarm threshold comprises:

adjusting the smoke alarm threshold to increase sensitivity to smoke if the CO sensor signal reaches the CO/smoke threshold.

13. The method of claim 12, wherein generating a smoke alarm comprises:

generating a smoke alarm if the smoke sensor signal reaches the smoke alarm threshold as adjusted to increase sensitivity.

14. A device comprising:

a first hazardous condition sensor for producing a first sensor signal;

a second hazardous condition sensor for producing a second sensor signal;

a controller producing a first alarm when the first sensor signal meets a first threshold and a second alarm when the second sensor signal meets a second threshold, and for adjusting the first threshold to change sensitivity of the controller to the first hazardous condition as a function of the first sensor signal and the second sensor signal.

15. The device of claim 14, wherein the first hazardous condition sensor comprises a smoke sensor.

16. The device of claim 15, wherein the smoke sensor comprises an ionization smoke sensor.

17. The device of claim 16, wherein the second hazardous condition sensor comprises a carbon monoxide sensor.

18. The device of claim 14, wherein the controller decreases sensitivity to the first sensor signal when the first sensor signal reaches an initial first threshold.

19. The device of claim 18, wherein the controller causes a first alarm to be generated if (a) the first sensor signal reaches a decreased sensitivity first threshold;

or (b) the first sensor signal is at or beyond the initial first threshold at expiration of a timeout period;

or (c) after sensitivity to the first sensor signal is decreased, the second sensor signal reaches a third threshold.

20. The device of claim 14, wherein the controller increases sensitivity to the first sensor signal if the second sensor signal reaches a third threshold before the first sensor signal reaches an initial first threshold.