System and Method of Airflow Monitoring for Variable Airflow Environments

• US 20160140822A1
• Filed: 11/19/2014
• Published: 05/19/2016
• Est. Priority Date: 11/19/2014
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Kurtz, Edward J., Lang, Scott R.
• Granted Patent: US 9,959,726 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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
• CPC Class Codes: G08B 29/043 of fire detection circuits

Abstract

A method of operating an aspirated smoke detector includes providing an ambient condition detector, establishing a first flow baseline for the detector, and, establishing a second, lower, flow baseline for the detector. A selected airflow is sampled, and determining if the airflow sample should be compared to the first flow baseline or the second flow baseline, and, responsive thereto determining if a trouble indictor should be generated.

Claims

1. An apparatus comprising:

an ambient condition detector

at least first and second predetermined flow thresholds;

a flow indicting signal;

control circuits in the detector, coupled to the flow indicating signal wherein the control circuits compare the signal to at least one flow threshold and responsive thereto determines if a trouble indicator should be generated.

2. An apparatus as in claim 1 where at least one of the first and second thresholds is stored in an electronic storage element and coupled to the control circuits.

3. An apparatus as in claim 1 where the flow indicting signal comprises one of a binary signal, and an analog signal.

4. An apparatus as in claim 3 wherein the signal values are indicative of one of a first flow rate or a second, lower flow rate.

5. An apparatus as in claim 1 where the detector comprises an aspirated smoke detector.

6. An apparatus as in claim 5 where at least one of the first and second thresholds is stored in an electronic storage element and coupled to the control circuits.

7. An aspirated smoke detector comprising:

control circuits coupled to a smoke indicating signal, first and second baseline indicating values and an indicator that couples realtime flow values to the control circuits, wherein the control circuits establish at least one parameter to determine if a trouble condition is present.

8. An aspirated smoke detector as in claim 7 wherein the at least one parameter comprises a value indicative of an acceptable variation between a sensed, real time flow value and at least one predetermined threshold.

9. An aspirated smoke detector as in claim 8 wherein the control circuits compare the flow indicting signal to both of the baselines and responsive thereto, make a determination as to the presence of the trouble condition.

10. A method comprising:

providing an ambient condition detector;

establishing a first flow baseline for the detector;

establishing a second, lower, flow baseline for the detector;

sampling a selected airflow; and

determining if the airflow sample should be compared to the first flow baseline or the second flow baseline, and, responsive thereto determining if a trouble indictor should be generated.

11. A method as in claim 10 including establishing a trouble limit value and using that value in determining if the trouble indictor should be generated.

12. A method as in claim 11 where determining if the if the trouble indicator should be generated includes determining if a variation between a selected baseline and the sample airflow value exceeds the trouble limit value.

13. A method as in claim 12 where providing includes providing an aspirated detector.

14. A method as in claim 13 which includes storing the trouble limit value in the detector.

15. A method as in claim 14 which includes storing the baselines in the detector.

16. A method as in claim 15 includes exposing the detector to the selected air low prior to sampling the airflow.

17. A method as in claim 16 which includes determining if a flow generating unit is in a first, active, state or a second, inactive, state after sampling the selected airflow.

18. A method as in claim 16 where, responsive to detecting the state of the unit, a sampled airflow value is compared to a selected baseline value.

19. A method as in claim 18 which includes providing a time based sequence of sampled air flow values.

20. A method as in claim 10 which includes associating a first sensitivity with the first flow baseline, and a second, different, sensitivity with the second flow baseline.