Card shelf fire suppression system and method

• US 6,404,629 B1
• Filed: 07/31/2000
• Issued: 06/11/2002
• Est. Priority Date: 07/31/2000
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Austin, Thomas A., Meeker, Matthew K.
• Primary Examiner(s): THOMPSON, GREGORY D
• Application Number:
  US09/622,000
• Time in Patent Office: 680 Days
• Field of Search: 622/592, 236/49-- 4, 337/1, 337/17, 337/297, 361/688, 361/690, 361/694-695, 454/184, 454/369, 169/44, 169/56, 169/59
• US Class Current: 361/690
• CPC Class Codes: H05K 7/1425 of standardised dimensions, e.g. 19"-subrack

Abstract

A card shelf fire suppression system includes a card shelf having a backplane and a plurality of slots. The slots are each configured to receive an electronic card adapted for engagement with the backplane. The system also includes an airflow path for providing airflow adjacent the electronic card for dissipating thermal energy generated by the electronic card. The system further includes a damper system disposed proximate the slots and operable to passively activate to substantially prevent airflow through the slots and adjacent the electronic card. The damper system includes a damper, a support, and a thermal fuse. In response to an elevated temperature condition, the thermal fuse deforms causing the damper to become unsupported by the support, thereby accommodating movement of the damper from an open position to a closed position to substantially prevent airflow to the electronic cards.

Claims

1. A card shelf comprising:

a backplane;

a plurality of slots each configured to receive an electronic card adapted for engagement with the backplane;

an airflow path for providing airflow adjacent the electronic card for dissipating thermal energy generated by the electronic card; and

a damper system disposed proximate the slots and comprising a damper and a thermal fuse coupled to the damper, the thermal fuse being responsive to a predetermined temperature condition to cause the thermal fuse to deform such that the damper moves to passively activate to substantially prevent airflow through the slots and adjacent the electronic card.

2. The card shelf of claim 1, wherein the damper system is operable to passively activate in response to a predetermined temperature condition.

3. The card shelf of claim 1, wherein the damper system is disposed upwardly from the plurality of slots.

4. The card shelf of claim 1, wherein the damper system further comprises a support coupled to the thermal fuse and operable to support the damper in a first position relative to the slots, the thermal fuse being responsive to a predetermined temperature condition to cause the thermal fuse to deform such that the damper travels from the first position to a second position relative to the slots.

5. The card shelf of claim 1, further comprising:

a plurality of side members disposed proximate the backplane; and

a top member disposed between the side members and upwardly from the slots;

the damper coupled to the top member; and

wherein the damper system further comprises;

a support disposed between the top member and the thermal fuse and operable to support the damper in a first position relative to the top member, the thermal fuse being responsive to a predetermined temperature condition to cause the thermal fuse to deform such that the damper travels from the first position to a second position relative to the top member.

8. The card shelf of claim 1, further comprising a top member disposed upwardly from the slots and coupled between a plurality of side members, and wherein the damper system further comprises:

a support disposed between the thermal fuse and the top member and operable to support the damper at a first position relative to the top member, the thermal fuse being responsive to a predetermined temperature condition to cause the thermal fuse to deform such that the damper travels from the first position to a second position relative to the top member.

6. A card shelf comprising:

a backplane;

a plurality of side members disposed proximate to the backplane;

a plurality of slots each configured to receive an electronic card adapted for engagement with the backplane;

a top member disposed between the side members and upwardly from the slots;

an airflow path for providing airflow adjacent the electronic card for dissipating thermal energy generated by the electronic card; and

a damper system disposed proximate the slots and operable to passively activate to substantially prevent airflow through the slots and adjacent the electronic card;

the damper system comprising;

a damper rotatably coupled to the top member

a thermal fuse coupled to the damper; and

a support disposed between the top member and the thermal fuse and operable to support the damper in a first position relative to the top member, the thermal fuse being responsive to a predetermined temperature condition to cause the thermal fuse to deform such that the damper plate rotates from a first position to a second position relative to the top member.

7. A card shelf comprising:

a backplane;

a plurality of slots each configured to receive an electronic card adapted for engagement with the backplane;

an airflow path for providing airflow adjacent the electronic card for dissipating thermal energy generated by the electronic card;

a damper system disposed proximate the slots and comprising a damper and a thermal fuse coupled to the damper, the thermal fuse being responsive to a predetermined temperature condition to cause the thermal fuse to deform such that the damper moves to passively activate to substantially prevent airflow through the slots and adjacent the electronic card;

a plurality of side members disposed proximate the backplane; and

a bottom member disposed between the side members and downwardly from the slots; and

wherein the damper system comprises;

a damper coupled to the bottom member;

a thermal fuse coupled to the damper;

a spring coupled to the damper and one of the side members; and

a support disposed between the bottom member and the thermal fuse and operable to support the damper in a first position relative to the bottom member, the thermal fuse being responsive to a predetermined temperature condition to cause the thermal fuse to deform such that the spring causes the damper to travel from the first position to a second position relative to the bottom member.

9. A passively activated damper system for a card shelf, comprising:

a damper coupled to a card shelf;

a thermal fuse coupled to the damper; and

a support coupled to the thermal fuse and operable to support the damper in a first position relative to the card shelf, the thermal fuse being responsive to a predetermined temperature condition to cause the thermal fuse to deform such that the damper travels from the first position to a second position relative to the card shelf.

10. The system of claim 9, wherein the support is coupled to the card shelf.

11. The system of claim 9, wherein the damper is rotatably coupled to the card shelf such that the damper rotates from the first position to the second position.

12. The system of claim 9, wherein the damper is disposed on an upwardly disposed portion of the card shelf such that gravitational forces cause the damper to travel from the first position to the second position.

13. The system of claim 9, further comprising a spring coupled to the damper and the card shelf, the spring operable to retract to cause the damper to travel from the first position to the second position.

14. The system of claim 13, wherein the damper is disposed on a downwardly disposed portion of the card shelf.

15. The system of claim 9, wherein the damper comprises a damper plate having an opening, and wherein the thermal fuse is disposed over the opening.

16. The system of claim 15, wherein the opening is disposed along an edge of the damper plate.

17. A method for passively controlling air flow to an electronic card in a card shelf, comprising:

providing a damper operable to control airflow to the electronic card and a thermal fuse coupled to the damper, the thermal fuse being responsive to a predetermined temperature condition;

supporting the damper at a location aligned with the thermal fuse in a first position relative to the electronic card such that the air flow passes adjacent the electronic card; and

passively activating the damper in response to the predetermined temperature condition such that the thermal fusse deforms to cause the damper to travel from the first position to a second position relative to the electronic card to substantially prevent air flow adjacent the electronic card.

18. The method of claim 17, wherein supporting the damper comprises supporting the damper with a support coupled to the card shelf and aligned with the thermal fuse.

19. The method of claim 17, wherein providing the damper comprises providing a damper plate rotatably coupled to an upwardly disposed portion of the card shelf such that gravitational forces cause the damper plate to travel from the first position to the second position.

20. The method of claim 17, further comprising providing a spring coupled between the damper and the card shelf such that retraction of the spring causes the damper to travel from the first position to the second position.

21. The method of claim 20, wherein providing the damper comprises providing the damper coupled to a downwardly disposed portion of the card shelf, and wherein the spring retracts to cause the damper to travel upwardly from the first position to the second position.

22. A card shelf comprising:

a backplane;

a plurality slots configured to receive an electronic card adapted for engagement with the backplane;

an inlet operable to receive and direct an air flow adjacent the electronic card;

an outlet operable to direct the air flow away from the electronic card; and

a damper system comprising a damper and a thermal fuse coupled to the damper, the thermal fuse being responsive to a predetermined temperature condition to cause the thermal fuse to deform such that the damper moves to passively activate to substantially prevent the air flow adjacent the electronic card.

23. The card shelf of claim 22, wherein the damper system is operable to travel from an open position relative to the outlet to a closed position relative to the outlet to substantially prevent air flow adjacent the electronic card.

24. The card shelf of claim 22, wherein the damper system further comprises a support coupled to the thermal fuse and operable to support the damper in a first position relative to the outlet, the thermal fuse being responsive to the predetermined temperature condition to cause the thermal fuse to deform such that the damper travels from the first position to a second position relative to the outlet.

26. The card shelf of claim 22, further comprising a top member having a plurality of holes disposed upwardly from the slots, the damper rotatably coupled to the top member;

and wherein the damper system further comprises a support disposed between the thermal fuse and the top member, the support operable to support the damper in an open position, the thermal fuse being responsive to the predetermined temperature condition to cause the thermal fuse to deform such that the damper travels from the open position to a closed to substantially prevent air flow adjacent the electronic card.

25. A card shelf comprising:

a backplane;

a plurality slots configured to receive an electronic card adapted for engagement with the backplane;

an inlet operable to receive and direct an air flow adjacent the electronic card;

an outlet operable to direct the air flow away from the electronic card;

a damper system comprising a damper and a thermal fuse coupled to the damper, the thermal fuse being responsive to a predetermined temperature condition to cause the thermal fuse to deform such that the damper moves to passively activate to substantially prevent the air flow adjacent the electronic card;

the damper disposed proximate the inlet;

the thermal fuse coupled to the damper;

a spring having a first end coupled to the damper and a second end coupled to a portion of the card shelf adjacent the inlet; and

a support coupled to the thermal fuse and operable to support the damper in a first position relative to the inlet, the thermal fuse being responsive to the predetermined temperature condition to cause the thermal fuse to deform such that the spring retracts to cause the damper to travel from the first position to a second position relative to the inlet to substantially prevent air flow adjacent the electronic card.