GB2213719A

GB2213719A - Sliding plate fire and smoke damper

Info

Publication number: GB2213719A
Application number: GB8900748A
Authority: GB
Inventors: David John Gaiger; Michael York
Original assignee: Actionair Equipment Ltd
Current assignee: Actionair Equipment Ltd
Priority date: 1988-01-13
Filing date: 1989-01-13
Publication date: 1989-08-23
Anticipated expiration: 2009-01-13
Also published as: GB2213719B; GB8800659D0; GB8900748D0

Abstract

The invention is directed to a fire and smoke damper which is especially suitable for air transfer applications through fire-rated doors, dry wall/partitions and ceilings and which comprises a sliding plate (16) loaded by springs (22) into a position where the plate shuts off the passage of air through the damper on operation of a thermal actuator and/or a fusible link (24). <IMAGE>

Description

Sliding Plate Fire and Smoke Damper This invention relates to a sliding plate fire and smoke damper.

Broadly, the invention is directed to a fire and smoke damper which is especially suitable for air transfer applications through fire-rated doors, dry wall/partitions and ceilings and which comprises a sliding plate springloaded to an air shut-off position on operation of a thermal actuator and/or fusible link.

Examples of dampers in accordance with the invention are shown in the accompanying drawings, in which Figures 1-3 are three exploded views of one particular damper in accordance with the invention; Figures 4-7 are front views of a cassette forming part of the damper; Figures 8-10 are sectional views through the damper; Figure 11 is an exploded perspective view of an actuator in the form of a cassette; Figures 12-16 are front and top plan views of the cassette shown in Figure 11; Figure 17 is an exploded perspective view similar to Figure 11 of a second form of actuator cassette; and Figures 18-24 are front and top plan views of the cassette shown in Figure 17.

Figure 1 shows a slim-line stainless steel sliding plate fire and smoke damper for air transfer applications through fire-rated doors, dry wall/partitions and ceilings.

It incorporates fail-safe spring-loaded instant closure means and the choice of two interchangeable and replaceable release and reset mechanisms with either thermal actuator and fusible link dual fail-safe operation or a combination thermal actuator 24 volt D.C. electro-magnet together with fusible link treble fail-safe operation. External manual release, resetting and testing facilities are also provided, as well as external visual indication of the damper status.

The damper has, at the front and rear, specially designed matching non-vision transfer grilles 10 and 12 with radius edges and countersunk fixing. These matching transfer grilles are supplied for fitting to both sides of a door, dry wall/partition or ceiling. The specific grilles illustrated are constructed in 18 gauge CR4 mild steel with a Plastisol front face coating and a reverse face backing coat, but it is to be understood that they can be made of other suitable material.

As shown in Figures 2 and 3, the damper has a sliding plate assembly 14 comprising flanged 18-gauge stainless steel sliding seal and static damper plates 16 and 18 with horizontal perforations which provide, when the seal plate 16 is in the open position, a free area of not less than that of the grilles 10 and 12 for the passage and transfer of ventilation air in either direction. The sliding seal plate 16 is retained on the static plate 18 by stainless steel shouldered rivets 20 and fails-safe to the instant closed position by the action of two stainless steel tension springs 22 on the melting and parting at a temperature of 2000 C. of an all-brass fusible link 24 attached to the sliding seal plate to form a fire and smoke resistant shield from either air flow direction.The fusible link functions independently and regardless of the choice or status of the release and reset mechanism, and removal of the fusible link provides the additional failsafe feature of instant damper closure which cannot be reversed until the proper replacement is made. It is also to be understood that the damper can be made to work, without the cassette, by the addition of a fixed pin engaging in the appropriate half of the fusible link.

Both damper plates 16, 18 together with a choice of two interchangeable and replaceable release and reset mechanisms with either being self-contained in a fixed or removable common multi-functional cassette 26 are housed within an 18-gauge galvanised steel slim-line damper casing 28 which has integral flanges 30 with pre-punched fixing and alignment holes for ease of installation. The damper can thus be readily accommodated in 1/2 hour fire-rated 44 mm thick and 1 hour fire-rated 54 mm thick doors as well as in fire-rated dry wall/partitions and ceilings of any thickness.

A choice of two interchangeable and replaceable release and reset mechanisms is available with either a thermal actuator (Mode 1) or a combination thermal actuator and 24 volt D.C. electro-magnet (Mode 2) being selfcontained in the compact common multi-functional cassette 27 with simple screw attachment direct to the damper static plate for easy withdrawal without disturbance to the damper other than the removal of the relevant transfer grille.

Removal of the release and reset mechanism cassette provides the further fail-safe feature of damper instant closure which cannot be reversed until the proper replacement is made.

The common multi-functional cassette 26 also contains, recessed from view but readily accessible through the countersunk holes provided in the frame of the relevant transfer grille, a release lever and a slotted head resetting shaft which are both externally operated. The release lever, when manually depressed, overrides all other functions to close the damper for periodic operational testing in accordance with British Standard Code of Practice, revision of CP413. The resetting shaft 32, when manually turned in a partial anti-clockwise direction, automatically resets the damper in the open positionassuming all other functions are intact.All this is illustrated for both Modes in Figures 4-7 wherein Figure 4 shows Mode 1 - cassette front elevation - release to failsafe instant damper closure; Figure 5 shows Mode 2cassette front elevation - release to fail-safe instant damper closure; Figure 6 shows Mode 1 - cassette front elevation - reset to damper open position; and Figure 7 shows Mode 2 - cassette front elevation - reset to damper open position.

The damper, on closing, regardless of and by whichever function, automatically disengages - within the multi-functional cassette - a spring-loaded damper set and status pin 34 one end of which is encapsulated with a distinctly red-coloured capping of plastics material.

Outward movement of this pin to an exposed position through another countersunk hole in the frame of the relevant transfer grille provides visual indication of damper status.

Figures 8-10 illustrate different relative positions of the grilles and plates of the damper. In particular, Figure 8 shows their position in Modes 1 and 2 - cassette side elevation - on manual or thermal actuator and/or electro-magnet release to fail-safe instant damper closure; Figure 9 shows Nodes 1 and 2 - cassette side elevation - on fusible link release to fail-safe instant damper closure; and Figure 10 shows Modes 1 and 2cassette side elevation - in reset to damper open position.

Modes 1 and 2 operation will now be described in some detail.

Mode 1 concerns thermal actuator and fusible link dual fail-safe operation. As shown in Figures 11-16, the thermal actuator comprises a helical-coil memory metal compression spring produced from a special Cu-Zn-Al brass alloy which is formulated to give a transformation (start to move) temperature above 400 C. whereby the close coilbound spring at ambient temperature will then expand and become open coiled at approximately 720 C., thereby forcing the damper set and status pin outwards and actuating the damper instant closure. On cooling, the spring reverts to the close-coiled state offering the significant advantage of repeatability without degrading and loss of memory until subjected to temperatures in excess of 1800 C. The thermal actuator ideally controls the damper closure in those frequent temporary heat rise situations without resort to the destruction of the fusible link. However, in combination with the fusible linkwhich melts at a temperature of 2000 C. - it provides a unique dual fail-safe operation in a full fire condition.

Figures 12-16 illustrate Mode 1 operation as follows Figure 12 - cassette front elevation - manual or thermal actuator and/or fusible link release to fail-safe instant damper closure; Figure 13 - cassette top plan view - manual or fusible link release to fail-safe instant damper closure; Figure 14 - cassette top plan viewthermal actuator or thermal actuator and fusible link release to fail-safe instant damper closure; Figure 15cassette front elevation - reset to damper open position; and Figure 16 - cassette top plan view - reset to damper open position.

Mode 2 concerns combination thermal actuator and 24 volt D.C. electro-magnet together with fusible link treble fail-safe operation. This is illustrated in Figures 17-24.

The electro-magnet is normally energised to hold open the damper, which will therefore instantly close when the electrical supply is interrupted, either as a function of a smoke detection system or due to failure of the electrical supply and in both events before the operation of the thermal actuator and fusible link due to an abnormal rise in temperature of a full fire condition. The addition of the electro-magnet provides an even more unique treble fail-safe operation. Preferably, the continuous electrical supply to the 24 volt D.C. electro-magnet is through a battery circuit and not through an automatic change-over system.

Figures 18-24 illustrate Mode 2 operation as follows Figure 18 - cassette front elevation - electromagnet release to fail-safe instant damper closure; Figure 19 - cassette top plan view - electro-magnet release to fail-safe instant damper closure; Figure 20 - cassette front elevation - manual or fusible link release to failsafe instant damper closure; Figure 21 - cassette top plan view - manual or fusible link release to fail-safe instant damper closure; Figure 22 - cassette top plan viewthermal actuator or thermal actutor and fusible link release to fail-safe instant damper closure; Figure 23cassette front elevation - reset to damper open position; and Figure 24 - cassette top plan view - reset to damper open position.

Dampers in accordance with the invention are suitable for both vertical and horizontal (ceiling) application, with the passage and transfer of ventilation air in either direction. The dampers are supplied with a flanged backing sleeve 38 (see Figure 1) which can have a sleeve depth of 40 mm, a top flange height of 8 mm, sides and bottom flange heights of 20 mm. Damper assemblies for use with such backing sleeves can have a depth of 42 mm, a top flange height of 8 mm, sides and bottom flange heights of 20 mm. The transfer grilles can be of a variety of sizes and shapes, according to the different needs of different purchasers.

Claims

1. A fire and smoke damper, especially for air transfer applications through fire-rated doors, dry wali/partitions and ceilings, comrising a sliding plate which is loaded by a spring to an air shut-off position on operation of a thermal actuator and/or fusible link.

2. A damper according to claim 1, in which release, resetting and testing means are associated with the sliding plate.

3. A damper according to claim 1 or claim 2, in which external visual indicating means are provided to indicate the position of the sliding plate.

4. A damper according to any one of claims 1-3, in which the sliding plate is flanked on both sides by airtransfer grilles which are designed for fitting to both sides of a door, wall, partition or ceiling.

5. A damper according to any preceding claim, in which the sliding plate slides over a static damper plate, the two plates being provided with perforations which, when in alignment, provide for the passage of air through the damper.

6. A damper according to claim 5, in which the sliding plate is retained on the static plate, for example by rivets or other fastening means allowing movement of the sliding plate with respect to the static plate.

7. A damper according to any preceding claim, in which spring-loading of the sliding plate is effected by two tension springs preferably made of stainless steel or other non-corroding metal.

8. A damper according to any preceding claim, in which a fusible link is attached to the sliding plate so that, on fusing of that link, the sliding plate is able to move due to its spring-loading into a position where it forms a fire and smoke resistant shield irrespective of the direction of air flow through the damper.

9. A damper according to claim 8 when appendant to claim 2, in which the fusible link functions independently and regardless of the choice or status of the release and reset means.

10. A damper according to claim 8 or claim 9, in which removal of the fusible link ensures that the sliding plate moves into an air shut-off position which cannot be reversed until the fusible link is replaced.

11. A damper according to claim 8 or claim 9, in which the damper is made effective for operation by a fixed pin which engages in the appropriate half of the fusible link.

12. A damper according to claim 2 or any claim appendant thereto, in which a choice of two interchangeable and replaceable release and reset means are provided with either being self-contained in a fixed or removable common multi-functional cassette.

13. A damper according to claim 12, in which one of the release and reset means comprises a thermal actuator, while the other comprises a combination thermal actuator and electro-magnet.

14. A damper according to claim 2 or any claim appendant thereto, in which the release and reset means comprise a release lever and a slotted head resetting shaft which are both externally operated.

15. A damper according to claim 1 substantially as described herein with reference to Figures 1-10 or as modified by Figures 11-16 or Figures 17-24.