GB2216792A

GB2216792A - Fire dampers

Info

Publication number: GB2216792A
Application number: GB8906328A
Authority: GB
Inventors: John James Mawdsley
Original assignee: GILBERTS
Current assignee: GILBERTS
Priority date: 1988-03-18
Filing date: 1989-03-20
Publication date: 1989-10-18
Anticipated expiration: 2009-03-20
Also published as: GB8906328D0; GB2216792B

Abstract

A fire damper comprises a mounting frame 10 for building into a wall, and an operative cell 22 of the shutter or pivoted blade type, demountably secured in the mounting frame 10. The cell 22 may be removed from the mounting frame 10 for inspection, without damaging the wall. This is achieved by removal of a transition duct section 14, followed by axial withdrawal of the cell 22. In its normal position the cell 22 is firmly held against lateral displacement by resilient corner location members 32 of the mounting frame 10, and against axial displacement by being sandwiched between the duct section 14 and an end location within the mounting frame. <IMAGE>

Description

Improvements in or relating to fire dampers The invention relates to fire dampers of the kind frequently fitted in ducting (especially industrial ventilation ducting) in which there is a damper preloaded into a closed position and thermally controlled retaining means which are adapted to hold the damper in an open position, but which, on detecting a temperature rise above a preselected threshold value, releases the retaining means and allows the damper to close under its preloading. One well known type of fire damper to which the invention may be applied essentially comprises a series of blades extending across a duct and pivoted on parallel axes, the arrangement being such that when the blades are in the open position, they present only their thicknesses to air flow through the duct, but in their closed position, they overlap or meet edge-to-edge to completely obturate the duct.Another well known type of fire damper to which the invention can be applied essentially comprises a metal shutter which in the open position has all its blades folded against each other, the whole assembly being entirely or almost entirely outside the duct, but which, on release, allows all the blades to unfold so that again the duct is completely obturated by the shutter. The most commonly used thermal detector is a fusible link.

In any case, the damper has a frame, which in effect forms part of the ducting, though in some instances, it could itself comprise the ducting.

Generally, some operating or control mechanism has to be housed within, on, or adjacent to the frame, and this is particularly the case with the pivoted blade type of damper where the mechanism may comprise links, or gear pinions or a gear rack-and-pinion. Such operating or control mechanism is conveniently located in a channel of the frame alongside the damper itself. A fusible link is suitably located in the damper itself, and is thus sensitive to temperature changes of the air in the ducting.

Sometimes-the ducting in which the damper is fitted passes through the wall of a building and the damper frame is built into the wall, the ducting being connected to the frame on each side of the wall. A problem then arises if it is necessary to gain access to the mechanism, for example to replace a blade, because it is necessary to remove part of the wall around the frame.

The present invention is intended to overcome this problem.

According to this invention a fire damper has a mounting frame which can be built into a wall if required, and an operative cell demountably fitted into the mounting frame and including a duct frame which effectively forms the whole or part of the ducting in which the damper is provided; the damper itself and operating and/or control mechanism therefor. The duct frame suitably contains a fusible link which controls, solely or in part, the operation of the damper. The advantage of the invention will be immediately apparent, in that the operative cell can be removed from the mounting frame, leaving the mounting frame in situ in the wall, to permit ready access to the damper, whilst leaving the wall intact.

According to a preferred feature of the invention, the operative cell is slidable into and out of the mounting frame though one end thereof and an end location is provided in the mounting frame against which the operative cell can be located. It is further preferred that sealing means are provided between the end location and the operative cell and such means may comprise an intumescent seal.

It is further preferred that the operative cell is sandwiched between the end location in the mounting frame and a part of ducting in which the damper is fitted, for example a transition duct which joins the fire damper to the main ducting. The sandwich arrangement substantially secures the operative cell against axial displacement. Preferably sealing means are provided between the said ducting and the operative cell and such means may comprise an intumescent seal.

Preferably, the mounting frame completely surrounds the operative cell and substantially prevents any lateral movement of the cell relatively to the mounting frame, and hence relatively to the wall in which the mounting frame is secured.

According to a further preferred feature of the invention the mounting frame includes corner location members adapted to receive corresponding corners of the operative cell so as to locate the cell against lateral motion. In the preferred construction, both the mounting frame and the operative cell are rectangular (as seen from one side) and there is a corner location in each corner of the mounting frame so that all four corners of the operative cell are located.

Preferably each corner location member is constructed so that it can deform outwardly to permit expansion of the operative cell, without destroying the lateral location of the cell. In the preferred construction, each corner location comprises a pair of fingers adapted to engage on adjacent edges of the operative cell at a corner thereof, but having a bowed or V portion which can yield in a closing direction to accommodate expansion of the operative cell. It is a preferred feature of the construction that the corner locations are outward of the inner boundaries of the mounting frame so that they permit sealing of the operative cell to the end location in the mounting frame.

The invention may also be broadly defined as an assembly comprising a mounting frame, which can be built into a wall if required, an operative cell demountably fitted into the mounting frame, and a releasable ducting portion adjacent the mounting frame, wherein the ducting portion, in its operative location, retains the operative cell in the mounting frame, but permits removal of the operative cell from the mounting frame when released.

Preferably, the ducting portion is securable to the mounting frame, suitably by quick-release means such as toggle catches.

One construction of a fire damper for mounting in the wall of a building and embodying the invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view, partially cut away, of the damper; Figure 2 is a cross-section through part of the damper showing the fitting of an operative cell into a mounting frame; and Figure 3 is a detail view of a corner location.

The fire damper includes a mounting frame 10 which is generally of channel-shaped cross-section as seen from either side. It will be noted from Figures 1 and 2, that at one side, the mounting frame is formed with a flange 12, which follows the rectangular shape of the frame itself, the internal dimensions of the flange 12 being such as to provide accommodation, with a close fit, for the end part of a transition duct 14, which is used to joint the damper to the air conditioning ducting in the building in which the damper is located. At the other side of the channel portion of the mounting frame 10, there is a similar flange 16, but the wall 18 of the housing at that side of the damper is deeper than the wall 20 at the opposite side so that the flange 16 forms the periphery of a rectangular duct smaller than that formed by the flange 12.The flange 16 can also accommodate a transition duct (not shown) at the other side of the fire damper to the transition duct 14.

When the fire damper is fitted into an opening through the wall of a building, the channel portion of the housing 10 is built into the blocks or bricks of the wall, building-in strips 21 carried externally on the channel portion being located between the courses of the blocks or bricks, embedded in mortar, and the housing thereby becoming firmly located in the wall. Hence, the housing 10 can only be removed by removing part of the wall itself.

The fire damper also includes a cell 22 which essentially comprises a stainless steel frame 24, within which are mounted a set of damper blades, two of which are indicated in Figure 2 at 26 and 28. The control and operating mechanism for the damper blades 26 and 28 is located at one side of the transition duct 14 and part of it is shown connected in operation to a motor drive (not shown). A fusible link 29 of the mechanism located upstream of the cell 22 but within the rectangle defined by the frame 24 of the cell 22, so that air drawn through the cell will pass freely over the link. The invention is applicable to both the pivoted blade and folded shutter type of fire damper, but a pivoted blade type has been illustrated in Figure 2.Also, it is applicable to a simpler damper having a shutter or blade arrangement which is simply spring loaded towards a damper-closed position, but retained open by a fusible link. However, the invention is not concerned with control and operating mechanism for the damper blades, nor with the construction of the damper blades, and therefore it is not necessary to describe these features of the embodiment in detail. It is sufficient for present purposes to mention that the frame 10 effectively replaces the conventional housing for the fire damper.

The flange 12 carries the fixed parts of a plurality of quick-release toggle catches 30, which engage corresponding moving parts on the transition duct to secure the transition duct to the mounting frame. In this embodiment there are five such catches altogether, two for securement at the upper wall of the transition duct and one for securement of each of the other walls.

The frame 24 has corner pieces 31 at each of its corners and on each side of the frame as illustrated in the drawings. It will be observed that the external dimensions of the frame 24 are such that it passes easily through the rectangular opening provided by the flange 12, but it will also be observed that the frame 24 is much larger than the opening provided by the flange 16.

In each corner of the mounting frame 10 there is a corner location member 32, see especially Figure 3, and this location member comprises a sheet metal angle having mounting portions 34 which abut respectively against two of the outer walls of the channel-shaped mounting frame 10 at the corner. Rivets 36 are employed to secure the angle bracket 32 to the walls of the mounting frame.

At their inner extremities, each of the walls 34 of the bracket 32 is provided with an inwardly directed flange 38, which has a returned angle portion 40 and an out-turned lip 42 parallel with the wall 32 from which the flange 38 projects. The angled portion 40 and the lip 42 thereby form a "V " flange, and it will be appreciated that if outwardly directed force is applied to the inner face of the lip 42, the angled portion 40 can yield, by turning upwardly and outwardly around its upper end, to accommodate some outward motion of the lip 42.

Now it will be observed from Figure 3, that the inner faces of the lips 42 on the corner location members are themselves located somewhat inwardly of the flange 12. The eight lips 42 provided by the four corner location members in the mounting frame 10, effectively define a rectangular opening, into which the frame 24 of the cell 22 can be located. However, the arrangement of the corner location members is such that this effectively defined rectangle is slightly smaller than the rectangle formed by the outer walls and corner pieces of the frame 24.

A strip of intumescent sealing material 44 is fastened to the inside face of the wall 18, and in this way, a completely rectangular seal of intumescent material is provided on the inside face of the wall 18.

After the mounting frame has been secured in the wall, the cell 22 can be introduced into the mounting frame 10, by passing it through the rectangular opening provided by the flange 12 on the mounting frame 10. In other words, the cell 22 is slid axially inwardly of the mounting frame. When the corners 31 at the leading side of the cell 22 encounter the lips 42 on the corner location members, they force those lips to move slightly outwardly as permitted by the angled portions 40, so that the cell 22 is tightly gripped by the eight lips 42 and thus firmly secured against lateral motion in any direction. The cell 22 is then slid further into the mounting frame 10, until the leading face of the frame 24 encounters the intumescent seal 44.At that stage, the cell 22 is fully housed within the mounting frame 10, and in fact, the frame 24 is of approximately the same width as the channel-shaped portion of the mounting frame 10.

To complete the fitting of the fire damper, another rectangular intumescent seal 46 is fitted to the trailing face of the cell 22, and then the transition duct 14 is pushed through the short duct provided by the flanges 12, until its leading end, which is formed with inturned lips 48, engages with the seal 46. The damper is then connected to the control and operating mechanism, the fusible link 29 being slid onto studs 47 and retained in place by polymeric caps 50. The transition duct 14 is then secured in this position.

It will be appreciated, that the cell 22 which contains all the operative parts of the fire damper is then effectively trapped between the wall 18 of the mounting frame 10 and the inturned lips 48 at the inner end of the transition duct 14, so that the cell 22 is held against axial motion. In the event of a rise in temperature, there will be no break in the seals on opposite sides of the cell 22, and indeed the intumescent seals 44 and 46 will tend to swell under applied heat.

The fire damper will then operate in the conventional manner, but if it is required to gain access to the fire damper, for instance to carry out servicing or repair work, it is necessary to remove the transition duct 14, to permit the cell 22 to be removed from the mounting frame 10 in the opposite direction to that in which it was fitted into the mounting frame. Once outside the mounting frame, the cell 22 is open to access, and indeed can be removed from the site altogether. However, it is not necessary to damage the wall, because the mounting frame 10 remains in position.

It will be appreciated that the invention is capable of various modifications from the construction which has been described with reference to the drawings.

For instance, instead of the V-shaped construction of the parts of the location members which grip the corners of the cell 22, there could be bowed flanges provided on the outer ends of the flanges 34. The bowed elements would contract on the application of the outwardly directed force, in much the same way that the V-shaped formations bend to allow the lips 42 to move outwardly.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

The invention is not restricted to the details of the -foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A fire damper comprising a mounting frame which can be built into a wall if required, and an operative cell demountably fitted into the mounting frame and including a duct frame which effectively forms the whole or part of the ducting in which the damper is provided.

2. A fire damper as claimed in Claim 1, wherein the operative cell is slideable into and out of the mounting frame though one end thereof and an end location is provided in the mounting frame against which the operative cell can be located.

3. A fire damper as claimed in Claim 2, wherein intumescent sealing means are provided between the end location and the operative cell.

4. A fire damper as claimed in Claim 2 or 3 wherein, in situ, the operative cell is sandwiched between the end location in the mounting frame and a part of ducting in which the damper is fitted, whereby the operative cell is substantially secured against axial displacement.

5. A fire damper as claimed in Claim 4, comprising quick-release means between the mounting frame and the ducting in which, in situ, the damper is fitted.

6. A fire damper as claimed in any preceding claim, wherein, the mounting frame completely surrounds the operative cell and substantially prevents any lateral movement of the cell relatively to the mounting frame, and hence relatively to the wall in which the mounting frame is secured.

7. A fire damper as claimed in any preceding claim, wherein the mounting frame includes corner location members adapted to receive corresponding corners of the operative cell so as to locate the cell against lateral motion.

8. A fire damper as claimed in Claim 7, wherein each corner location member is constructed so that it can deform outwardly to permit expansion of the operative cell, without destroying the lateral location of the cell.

9. A fire damper as claimed in Claim 8, wherein each corner location comprises a pair of fingers adapted to engage on adjacent edges of the operative cell at a corner thereof, but having a bowed or V portion which can yield in a closing direction to accommodate expansion of the operative cell.

10. A fire damper as claimed in any of Claims 7, 8 or 9, wherein the surfaces of the corner locations which engage the operative cell are outward of the inner boundaries of the mounting frame so that they permit sealing of the operative cell against the end location in the mounting frame.

11. A fire damper assembly comprising a mounting frame, which can be built into a wall if required, an operative cell demountably fitted into the mounting frame, and a releasable ducting portion adjacent the mounting frame, wherein the ducting portion, in its operative location, retains the operative cell in the mounting frame, but permits removal of the operative cell from the mounting frame when released.

12. A fire damper substantially as hereinbefore described, with reference to the accompanying drawings