Smoke detection method and system

• US 20090140868A1
• Filed: 12/26/2006
• Published: 06/04/2009
• Est. Priority Date: 12/29/2005
• Status: Abandoned Application

• Current Assignee: David Booth
• Original Assignee: David Booth
• Inventors: Booth, David
• Application Number:
  US11/645,816
• Publication Number:
  US 20090140868A1
• Time in Patent Office: Days
• US Class Current: 340/628
• CPC Class Codes: G08B 17/10 Actuation by presence of smoke or gases , e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means

Abstract

A smoke detection method includes ramp-counting of non-decreasing smoke level samples for detecting smoldering fire conditions and counting of obscuring smoke level samples for detecting other-than-smoldering fire conditions. The ramp-counting of non-decreasing smoke level samples includes increasing a smoke detection ramp count for each successive smoke level sample that does not decrease from a previous one and resetting the smoke detection ramp count whenever a smoke level sample decreases relative to a previous one.

Claims

1. A smoke detection method, comprising:

detecting plural successive smoke level samples;

increasing a smoke detection ramp count for each successive smoke level sample that does not decrease from a previous one;

resetting the smoke detection ramp count whenever a smoke level sample decreases relative to a previous one; and

triggering a smoke detection alarm whenever the smoke detection ramp count exceeds a predetermined threshold.

2. The method of claim 1 further comprising:

determining whether a predetermined number of smoke level samples are greater than an alarm threshold; and

triggering a smoke detection alarm whenever the predetermined number of smoke level samples are greater than the alarm threshold.

3. The method of claim 2 further including:

automatically setting a clean air value corresponding to a no-smoke condition; and

automatically setting the alarm threshold as a predetermined proportional value of the clean air value.

4. The method of claim 1 further comprising:

detecting a temperature; and

triggering a smoke detection alarm whenever the temperature is greater than a predetermined temperature limit.

5. The method of claim 1 in which detecting the plural successive smoke sample levels includes detecting optical obscuration, whereby decreases in smoke level samples correspond to increases in optical obscuration and increases in smoke level samples correspond to decreases in optical obscuration.

6. The method of claim 5 in which detecting optical obscuration includes detection with a light emitter in both an ON state and an OFF state.

7. A smoke detection method, comprising:

ramp-counting non-decreasing smoke level samples for detecting smoldering fire conditions; and

counting obscuring smoke level samples for detecting other-than-smoldering fire conditions.

8. The method of claim 7 further comprising detecting whether a detector temperature is greater than a threshold temperature to provide a third fire detection mechanism.

9. The method of claim 7 in which ramp-counting non-decreasing smoke level samples includes increasing a smoke detection ramp count for each successive smoke level sample that does not decrease from a previous one and resetting the smoke detection ramp count whenever a smoke level sample decreases relative to a previous one.

10. The method of claim 7 in which counting obscuring smoke level samples includes determining whether a predetermined number of smoke level samples are greater than an alarm threshold.

11. The method of claim 7 further including:

automatically setting a clean air value corresponding to a no-smoke condition; and

automatically setting an alarm threshold as a predetermined proportional value of the clean air value for counting obscuring smoke level samples.