NZ756114B2 - Improvements to dampers - Google Patents

Abstract

damper for an air circulation system comprises a frame and a flange extending from the frame. The flange is provided with a resilient intumescent material on at least one face thereof, wherein the at least one face is perpendicular to an adjacent side wall of the frame. The resilient intumescent material expands when heated (for example in the presence of fire) and a seal between the flange and an adjacent surface is improved. aterial expands when heated (for example in the presence of fire) and a seal between the flange and an adjacent surface is improved.

Description

James & Wells ref: [303506DIV/99] IMPROVEMENTS TO DAMPERS TECHNICAL FIELD The present invention relates to dampers for air circulation systems, and in particular to apparatus and systems for locating and sealing a damper, for example a fire damper, within a wall cavity.

BACKGROUND ART Air circulation systems run through regions of a building to which air is to be delivered. Such circulation systems can in some instances be used to deliver conditioned air. Ducts or channels are employed to run through the wall spaces between rooms in a building, and can also be used to channel air between the floors of a building.

Often air circulation systems must also run through walls and floors which are designed to act as fire barriers. These barriers are generally constructed from fire resistant materials which will retard the progress of fire and prevent it from spreading to other regions or areas of a building.

To prevent the spread of smoke and/or fire over an entire structure, smoke dampers, fire dampers, and combined fire/smoke dampers (all generically referred to as “dampers” herein) have been developed for air circulation systems. These dampers provide components which are sited adjacent to, or within, a fire barrier surface such as a wall, floor or ceiling. The damper acts as a stop, valve component or closing element in conjunction with an air circulation channel. One example of such a damper is described in the applicant’s New Zealand Patent No.579684.

As well as preventing the spread of smoke and fire through the damper, it is important that smoke and fire cannot easily spread through the wall or floor via the penetration or cavity into which the damper has been mounted. Past mounting systems have included the use of a fire resistant mineral wool which is packed into a clearance space between the damper and the wall cavity, and thereby inhibits the movement of smoke and fire through the cavity. However, this system can be difficult to install properly.

An additional requirement is that the space between the damper sleeve and the wall cavity be insulated against heat transfer. In some cases the mineral wool referred to above acts as this insulation. Other systems use a spacer between the damper and the cavity, such that the air gap created provides the necessary thermal insulation. Such systems may also be difficult to install properly, particularly if the James & Wells ref: [303506DIV/99] cavity created in the wall or floor is an irregular shape.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of “including, but not limited to”.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF THE INVENTION According to one aspect of the present invention there is provided a spacer for a damper, the spacer comprising a base portion, a web portion connected at a proximal end to the base portion and extending at an angle from the base portion, and a ramp portion connected to a distal end of the web portion, the ramp portion extending toward a plane of the base portion.

Preferably the spacer is of unitary construction. More preferably the spacer is formed from a single sheet of steel.

Preferably the base portion comprises an abutment portion for limiting an extent to which the base portion can be inserted into a channel or aperture in use.

Preferably the base portion has a tapered portion at a distal end of the base portion to the connection with the web portion.

Preferably a clearance between the plane of the base portion and the ramp portion is around 2mm.

According to a second aspect of the present invention there is provided a spacer for a damper, the spacer comprising a first part and a second part, each of the first and second parts comprising a James & Wells ref: [303506DIV/99] respective base portion, a web portion connected at a proximal end to the respective base portion and extending at an angle from the base portion, and a ramp portion connected to a distal end of the respective web portion, each ramp portion extending toward a plane of the respective base portion, wherein the first and second parts are connected together along adjacent side edges of the base portions.

Preferably the planes of the first and second base portions form an angle of substantially 90°.

Preferably the spacer is of unitary construction. More preferably the spacer is formed from a single sheet of steel.

Preferably at least one of the base portions comprises an abutment portion for limiting an extent to which the respective base portion can be inserted into a channel or aperture in use.

Preferably, each base portion has a tapered portion at a distal end of the base portion to the connection with the respective web portion.

Preferably a clearance between the plane of each base portion and the respective ramp portion is around 2mm.

According to a third aspect of the present invention there is provided a damper for an air circulation system comprising a frame and a flange extending from the frame, the flange provided with a resilient material on at least one face thereof.

Preferably the resilient material is intumescent.

Preferably the resilient material comprises a felt, more preferably a sodium silicate type felt.

Preferably the frame comprises four sides, each side provided with a flange, each flange provided with a resilient material on at least one face thereof.

Preferably the damper is a fire damper.

According to a fourth aspect of the present invention there is provided a damper for an air circulation system provided with at least one spacer of the first or second aspects.

Preferably the damper is a damper of the third aspect.

Preferably the frame comprises four interconnected sides forming four corners, each side provided with a flange, each flange provided with a resilient material on at least one face thereof, the damper further comprising a spacer of the second aspect mounted to the frame at each corner.

James & Wells ref: [303506DIV/99] Preferably each spacer is captured between the frame and at least one flange.

Preferably the resilient material is intumescent.

According to another aspect of the invention a spacer for a damper is substantially as herein described with reference to Figures 1-4 or Figures 5-8.

According to another aspect of the invention a damper is substantially as herein described with reference to Figure 9.

According to a further aspect of the present invention a damper provided with at least one spacer is substantially as herein described with reference to Figures 1-4 and Figures 9-12 or Figures 5-12.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

BRIEF DESCRIPTION OF DRAWINGS Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which: Figure 1 Is a perspective view of a spacer for a fire damper according to one embodiment of the present invention; Figure 2 is a plan view of the spacer of Figure 1; Figure 3 is a front elevation of the spacer of Figure 1; Figure 4 is a side elevation of the spacer of Figure 1; Figure 5 is a perspective view of a spacer for a fire damper according to a second embodiment of the present invention; Figure 6 is a plan view of the spacer of Figure 5; Figure 7 is a front elevation of the spacer of Figure 5; Figure 8 is a side elevation of the spacer of Figure 5; Figure 9 is a perspective view of a fire damper of the present invention; Figure 10 is a diagrammatic partial cross-section side view of a fire damper of the present James & Wells ref: [303506DIV/99] invention, provided with a spacer of the present invention, being inserted into a cavity in a wall.

Figure 11 is a diagrammatic partial cross-section of the fire damper and spacer of Figure 10 installed in the cavity.

Figure 12 is a diagrammatic partial cross-section of the fire damper and spacer of Figure 10 being inserted into an insufficiently large cavity.

BEST MODES FOR CARRYING OUT THE INVENTION Referring first to Figures 1 to 4, a spacer for a damper according to one aspect of the present invention is generally referenced by arrow 100. The spacer 100 comprises a base portion 1 and a web portion 2 connected to the base portion 1 at one end 3 and to a ramp portion 4 at the opposite end 5.

As best seen in Figure 3, the base portion 1 is preferably substantially flat, and the web portion 2 extends at an angle A to the plane B of the base portion 1. The angle A is preferably between 20° and 60°, more preferably around 45°. The length of the web portion 2 and the angle A are selected such that the clearance between the end 5 of the web portion and the plane B of the base portion 1 is a required distance G. In some embodiments the distance G may be determined by reference to local regulations regarding a minimum allowable clearance between the walls of a damper and the cavity into which the damper is mounted. In an embodiment the distance G is calculated as follows: G ≥ ½ (0.01L+10mm) where L is equal to the length of the side of the damper frame which is adjacent to the side which the base portion 1 is mounted on when the spacer is in use.

Still referring in particular to Figure 3, the ramp portion 4 extends at an angle to the web portion 2, toward the plane B of the base portion 1. The ramp portion 4 forms an angle C of between 10° and 45°, more preferably around 45°, to the plane B of the base portion.

The angle C and the length of the ramp portion 4 are selected such that there is a clearance space 6 between the ramp portion 4 and the plane B of the base portion 1. This clearance space 6 is preferably small, for example around 2mm. As is explained further below, the clearance space 6 is selected to limit a maximum deflection of the web portion 2 when the spacer is in use.

Referring next to Figures 1 and 2 in particular, the base portion 1 preferably has a tapered portion 7 at a distal end of the base portion 1 to the connection with the web portion 2. In a preferred embodiment James & Wells ref: [303506DIV/99] the tapered portion 7 tapers to an apex 8. This tapered portion 7 may assist in mounting the spacer 100 to a damper, as is described further below.

The base portion 3 may also be provided with an abutment portion 9 which projects away from the plane B of the base portion 1. The abutment portion 9 may limit the extent to which the base portion 1 can be inserted into a channel, aperture, or other similar formation in use.

As is best seen in Figure 2, the spacer 100 is preferably widest at the intersection of the base portion 1 and the web portion 2, and preferably tapers from this intersection towards the end of the ramp portion In a preferred embodiment the spacer 100 is of unitary construction, and is preferably formed from a single sheet of steel. In a preferred embodiment the steel is a minimum of 0.75mm thick (22 gauge).

Referring next to Figures 5-8, another embodiment of the spacer is shown, generally referenced by arrow 101. The spacer 101 comprises a first part, generally referenced by arrow 10, and a second part, generally referenced by arrow 11.

The first part comprises a base portion 1a, web portion 2a and ramp portion 3a. The relative relationship between the base portion 1a, web portion 2a and ramp portion 3a is the same as that between the base portion 1, web portion 2 and ramp portion 3 of the spacer 100 described above.

The second part 11 comprises a base portion 1b, web portion 2b and ramp portion 3b. The relative relationship between the base portion 1b, web portion 2b and ramp portion 3b is also the same as that between the base portion 1, web portion 2 and ramp portion 3 of the spacer 100 described above.

The first and second parts 10, 11 are preferably mirror images, and are preferably connected together along a side 12a, 12b of the base portions 1a, 1b. The angle between the planes of the base portions 1a, 1b is preferably substantially 90°, so that the spacer 101 can be mounted to the corner of a damper in use, as is described further below.

As with spacer 100, spacer 101 is preferably of unitary construction, and is preferably formed from a single sheet of steel. In a preferred embodiment the steel is a minimum of 0.75mm thick (22 gauge).

Referring next to Figures 9-11, a damper of the present invention is generally referenced by arrow 102.

The damper 102 is shown with a spacer 100 and a spacer 101 installed.

The internal mechanism (not shown) of the damper 102 forms no part of the invention, and may comprise any known damper mechanism, for example curtain-type, motorised etc, or any other suitable James & Wells ref: [303506DIV/99] mechanism.

The damper 102 comprises a frame 20. At least one flange 21 extends from the frame 20. In a preferred embodiment the frame is substantially square or rectangular, and a flange 21 extends from each of the four sides 22, preferably substantially perpendicularly to the respective side 22.

A face 23 of each of the flanges 21 which is perpendicular to the adjacent side 22 is provided with a resilient material 24. The resilient material is preferably a felt, more preferably a sodium silicate type felt. As well as their ability to withstand elevated temperatures, sodium silicate felts have the additional advantage of being intumescent. The resilient material is preferably between around 2mm and 15mm thick, most preferably around 3mm thick. The resilient material may be attached to the flange by any suitable means, but most preferably by the use of a suitable high temperature adhesive.

When the damper is installed in a cavity the resilient material is clamped against a wall. The resilient material 24 provides a seal against the flow of air or smoke immediately upon proper installation. In embodiments where the resilient material is also intumescent, the intumescent material expands when heated (for example in the presence of fire) and the seal is improved.

In a preferred embodiment the damper 102 is provided with at least one spacer 100/101. In a preferred embodiment each flange 21 is connected to the frame 20 in such a way as to create an opening or channel 25 between the frame 20 and the flange 21. For example, the flange 21 may be manufactured from a substantially ‘L’ shaped material such as angle iron, and may be bolted to the frame 20, thereby creating a narrow channel between the adjacent sides of the flange 21 and the frame 20. In some embodiments the sides of the opening or channel 25 may be closed (that is, in contact with each other) when the flange 21 is bolted to the frame 20, and may only be forced apart to form the channel 25 when the spacer 100/101 is urged between the flange 21 and the frame 20.

The base portion or portions 1, 1a, 1b of the spacer 100/101 is preferably inserted into and thereby captured by the walls of the channel or aperture 25. The depth to which the base portion(s) 1, 1a, 1b are inserted is limited by the abutment portion(s) 9, 9a, 9b.

Referring next to Figure 10, a damper 102 which has been provided with a spacer 100 of the present invention is shown being installed into a cavity D in a wall E. As can be seen, the ramp portion 4 makes contact with an outer edge F of the cavity D first. The ramp portion 4 tends to centre the damper 102 within the cavity D, and assists in installation of the damper 102 by guiding the damper 102 into the cavity D and preventing any part of the spacer from catching on the outer surface of the wall E.

As shown in Figure 11, the cavity D is preferably sized such that the web portion 2 must deflect slightly James & Wells ref: [303506DIV/99] for the damper 102 to be fully inserted into the cavity D. The deflection may be as a result of bending of the connection between the web portion 2 and the base portion 1, bending of the web portion 2 itself, or both.

By sizing the cavity D such that some deflection of the web portion 2 is required, the damper 102 is held securely within the cavity. However, as shown in Figure 12, if the cavity D is too small (for example, if the cavity provides less clearance between the damper and the internal wall of the cavity than is required by local regulations), then the deflection of the web portion 2 is preferably so great that there is no clearance remaining between the end 26 of the ramp portion 4 and the frame 20 of the damper 102. In this case the web portion 2 cannot deflect any further, and the damper 102 cannot be inserted into the aperture D without the use of excessive force. In this way the design of the spacer 100, 101 assists with installation of the damper 102, while also ensuring that the damper 102 cannot be inserted into a cavity which provides insufficient clearance around the damper.

In preferred embodiments a damper 102 may be supplied with spacers 100 and/or spacers 101 installed. In this way no installation of spacers is required on-site. However, in other embodiments the spacers may be installed onto the damper on-site.

The spacers 100/101 of the present invention may be used with any suitable damper, and the damper 102 of the present invention may be used with spacers of the prior art, although particular advantages may be realised by use in the damper 102 in combination with one or more of the spacers 100, 101 of the present invention.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.

Claims (8)

WHAT WE CLAIM IS:

1. A damper for an air circulation system comprising: a frame; a flange extending from the frame; and a resilient intumescent material attached to at least one face of the flange, wherein the at least one face is perpendicular to an adjacent side wall of the frame.

2. The damper of claim 1 wherein, in use, the resilient intumescent material forms a seal between the flange and a wall to which the damper is mounted.

3. A damper according to claim 1 or 2 wherein the frame comprises four sides, each side provided with a flange, each flange provided with a resilient material on at least one face thereof.

4. A damper according to any one of claims 1 to 3 wherein the resilient intumescent material comprises a felt.

5. A damper according to claim 4 wherein the felt is of a sodium silicate type.

6. A damper according to any one of the preceding claims wherein the resilient intumescent material is between 2mm and 15mm thick.

7. A damper according to claim 6 wherein the resilient intumescent material is 3mm thick.

8. A damper according to any one of claims 1 to 5 wherein the damper is a fire damper.