Sensing chamber with enhanced ambient atmospheric flow

• US 7,656,302 B2
• Filed: 11/20/2006
• Issued: 02/02/2010
• Est. Priority Date: 11/20/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Lang, Scott R.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US11/561,532
• Publication Number:
  US 20080117065A1
• Time in Patent Office: 1,170 Days
• Field of Search: 340/628, 340/629, 340/630, 340/632, 128/203.16, 128/203.27, 128/204.17, 128/204.22, 732/042.2, 738/61, 738/630.3, 73/250.1, 738/650.3, 252/70, 399/92, 399/94, 62/94
• 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
• CPC Class Codes: G08B 17/107 for detecting light-scattering due to smoke
• CPC Class Codes: G08B 17/113 Constructional details

Abstract

A sensing chamber promotes an inflow of ambient atmosphere by establishing an internal temperature gradiant. A closed loop control system can be provided to maintain the gradiant.

Claims

1. A smoke, Carbon Monoxide (CO), Carbon dioxide (CO2) or Nitrogen (N) sensing chamber comprising:

a hollow housing having first and second regions separated by at least one flow opening,

said first region, except for the at least one flow opening, does not have any outflow ports and has at least one atmospheric inflow port;

said second region, except for the at least one flow opening, does not have any inflow ports and has at least one outflow port; and

a non-movable flow inducing element carried in at least one of the first or second regions of the housing to create a temperature gradient therein.

2. A chamber as claimed in claim 1 wherein the element comprises at least one of a heating element, or a cooling element.

3. A chamber as in claim 1 which includes a temperature indicating feedback element.

4. A chamber as in claim 3 which includes a source of radiant energy and a sensor thereof.

5. A chamber as in claim 4 where the temperature gradient induces flow of ambient atmosphere into the chamber.

6. A chamber as in claim 3 which includes temperature regulating circuitry coupled to the flow inducing element and the feedback element.

7. A chamber as in claim 1, where at least one non-movable flow inducing element is located in a the first region associated with the inflow port and at least one non-movable flow inducing element is located in the second region associated with the outflow port.

8. A chamber as in claim 7 where the at least one flow inducing element located in the second region associated with the outflow port is a non-movable cooling element.

9. A chamber as in claim 7 which includes a non-movable heating element located in the first region associated with the inflow port.

10. A detector comprising:

an aspirated sensing chamber that includes first and second regions separated by at least one flow opening and a temperature gradient between the first and second regions is the sole cause of atmospheric flow into, between and out of said chamber, said temperature gradient being provided by a non-movable flow inducing atmospheric heating element in at least one of the first or second regions of the sensing chamber.

11. A detector as in claim 10, the detector having a housing which carries the chamber.

12. A detector as in claim 10 which includes closed loop temperature control circuitry.

13. A detector as in claim 12 where the chamber includes an atmospheric cooling element.

14. A detector as in claim 13 where the sensing chamber includes inflow port and an outflow port.

15. A detector as in claim 14 wherein except for the at least one flow opening between the first and second regions, the first region only contains inflow ports and the second region only contains outflow ports.

16. A method comprising:

establishing a chamber for sensing an airborne ambient condition;

separating the chamber into first and second regions by at least one flow opening;

establishing flow between the first and second regions and into the chamber only by establishing a temperature gradient between the first and second regions of the chamber to induce an inflow of ambient atmosphere into the chamber; and

sensing a concentration of the ambient condition in the chamber.

17. A method as in claim 16 where establishing a temperature gradient includes heating ambient atmosphere in part of the chamber.

18. A method as in claim 17 where establishing a temperature gradient includes cooling ambient atmosphere in part of the chamber.

19. A method as in claim 16 which includes sensing a temperature parameter and adjusting the gradient accordingly.

20. A method as in claim 16 where ambient atmosphere inflows only into the first region and outflows only from the second region.