DK1838999T3

DK1838999T3 - Damper

Info

Publication number: DK1838999T3
Application number: DK05821511.2T
Authority: DK
Inventors: Heikki Hänninen
Original assignee: Flaekt Woods Ab
Priority date: 2005-01-17
Filing date: 2005-12-22
Publication date: 2018-05-28
Also published as: FI120848B; FI20050049A0; NO340152B1; EP1838999B1; WO2006075045A1; EP1838999A4; EP1838999A1; FI20050049A; NO20074196L

Abstract

A smoke damper is disclosed comprising a substantially rectangular frame installable in a ventilation air duct, the frame having pivotally mounted thereon at least one rotatable slat (2), the slat(s) being rotatable with the help of a separate mechanism by about 90° between an open position and a closed position, the slat having a first long edge (2') and second long edge (2") as the opposite slat edge relative to the first edge, and the slat further having attached thereto an elastic seal (3) and an intumescent sealant (4), whereby the elastic sealant (4) is attached at least onto the first long edge (2') of the slat so as to extend substantially over the entire length of the slat edge. The invention is implemented by way of attaching the intumescent sealant (4) at least onto the second edge (2") of at least one slat (2) so as to extend substantially over the entire length of the slat edge and that the intumescent sealant (4) is covered by a continuous-section strip (7) capable of moving outward from said long slat edge under the swelling action of the intumescent sealant.

Description

DESCRIPTION

[0001] The present invention relates to a smoke damper comprising a substantially rectangular frame installable in a ventilation air duct, the frame having pivotally mounted thereon at least one rotatable slat, the slat(s) being rotatable with the help of a separate mechanism by about 90° between an open position and a closed position, the slat having a first long edge and a second long edge as the opposite slat edge relative to the first edge, and the slat further having attached thereto an elastic seal and an intumescent sealant, whereby the elastic seal is attached at least onto the first long edge of the slat so as to extend substantially over the entire length of the slat edge, and whereby the intumescent sealant is attached at least onto the second edge of the slat so as to extend substantially over the entire length of the slat edge.

[0002] Forced central air-conditioning systems generally serve very different spaces connected to each other. In the interest of fire protection, a facility of separating such spaces from each other has become indispensable. Since the forced-air ducts may under a fire act as efficient distributors of combustion gases, flames and heat, it has become extremely important to develop automatically shutting dampers in air ducts. To this end, modern air-conditioning systems are compartmentalized and the divisions separating the compartmentalized spaces are provided with smoke dampers, for instance.

[0003] Smoke dampers are used in air ducts having either a circular or rectangular cross section. From FI Pat. No. 105129 is known a smoke damper suited for installation in a round duct.

[0004] The present invention is directed to both a smoke damper installable in an air duct of rectangular cross section and a smoke damper installable in round ducts with the help of mounting flanges. The smoke damper disclosed herein incorporates at least one slat adapted to be openable/closable by a separate actuator, whereby the slat(s) in the closed position serve to prevent access of combustion gases through the smoke damper under a fire. Typically, a smoke damper functions such that under normal operating conditions the damper is open, i.e., has its slat or slats rotated substantially parallel to the air flow. The control system has connected thereto a sensor that is capable at a temperature rise or detection of smoke (due to fire) of triggering the actuator mechanism rotating the slats, whereby the slats are rotated by 90° thus closing the air duct.

[0005] However, a shortcoming of this kind of smoke damper has been found in the insufficient gas-tightness thereof. The slat edges are generally provided with elastic rubber seals that unfortunately during the progress of a fire and at the increasing temperature thereof melt away thus allowing the damper to leak.

[0006] From GB 2 259 249 A, which discloses all the features of the preamble of claim 1, is known a fire damper having at least one shut-off element (slat) and an actuator capable of forcing the shut-off element into its closed position in a fire situation. This fire damper features an elastic seal and an intumescent sealant capable of swelling under heat, both elements being arranged in such a fashion relative to each other in the closed position of the damper that in a fire situation under the heat allows the intumescent sealant to compress the elastic seal against its backing surface thus preventing air flow past the elastic seal before the elastic seal begins to melt. In a similar fashion, FI Utility Model No. 5654 discloses a seal structure for a fire damper using a conventional elastic seal and an intumescent seal swelling under heat. The fire damper construction of this utility model is implemented by way of providing the air-duct-closing element with a seal of intumescent material cast in place and a separate elastic seal, such as a rubber or silicon seal, that makes the damper air-tight when it is closed at a normal temperature. The cast intumescent sealant is located relative to the elastic seal so that it after casting secures the elastic seal in place. Hence, clamping the elastic seal in place does not need any separate worksteps, but rather, after casting and curing, the cast intumescent sealant serves as clamping means for the elastic seal. In one embodiment of the construction, the base flange of the continuous-section elastic seal remains embedded in the cast intumescent sealant. The elastic seal and the intumescent sealant are located either at the edge of the rotatable shut-off element (slat) or in the wall part of the fire damper. In this arrangement, however, the elastic seal is invariably situated partially embedded in the intumescent sealant.

[0007] From GB 1 586 362 A is known a strip seal containing intumescent material. The strip seal is of flexible material, for example a brush-like material. The strip seal tends to melt very easily, whereby it offers no cover for the intumescent material during a fire.

[0008] The problem is, that the intumescent sealant under a fire eventually tends to become brittle and disintegrate thus allowing the fire damper to leak.

[0009] It is an object of the present invention to provide a smoke damper offering an extended time of fire resistance, yet featuring a simple construction that is cost-efficient to manufacture. The fire damper according to the invention is characterized in that the intumescent sealant is covered by a continuous-section strip of fire-resistant material capable of moving outward from said long slat edge under the swelling action of said sealant, and that the intumescent sealant is seated in a groove made onto the second long edge and having a continuous-section metallic strip located therein so as to cover the intumescent sealant, and that the cross section of the strip is substantially V-shaped and that the strip is located onto the intumescent sealant material into the groove in such a position that the V-shaped corner edge of the strip is pointing outward from the groove, whereby the strip remains firmly clamped in place by virtue of its ν'-shape.

[0010] A preferred embodiment of the exhaust air damper according to the invention is characterized in that the first long edge of the slat has a groove substantially identical with that made on the second long edge, and that said grooves are situated close to the corners of the slat edges such that, when two adjacent slats face each other by their edges in the closed position of the damper, the elastic seal running along the long edge of one slat meets the long edge of the next adjacent slat on the nongrooved area of the adjacent long slat edge thus sealing the interslat gap, and that the groove made on the long edge of said next adjacent slat contains intumescent sealant covered by said continuous-section strip in such a fashion that a gap remains between said covering strip and the nongrooved area of the long edge of the next adjacent slat in a situation where the intumescent sealant has not undergone swelling.

[0011] Another preferred embodiment of the exhaust air damper according to the invention is characterized in that the sides of the V-shaped metallic continuous-section strip have different widths and that the metallic strip is located in the groove so as to align the narrower side of the V-shape closer to the centerline of the long edge of the slat.

[0012] Among other features of the present invention, the smoke damper disclosed herein offers extended gas-tightness during the progress of a fire by virtue of having the intumescent sealant protected by the metallic strip from the tendency of the sealant to become brittle under progressing fire.

[0013] The invention is next described in more detail with the help of a preferred exemplifying embodiment by making reference to the appended drawings in which FIG. 1 shows a smoke damper in a view taken along the air duct with the damper slats in their closed position; FIG. 2 shows a partially sectional side view of the smoke damper of FIG. 1; FIG. 3 shows a cross-sectional view of a slat in a smoke damper according to the invention; and FIG. 4 shows a cross-sectional view of a preferred embodiment of the continuous-section strip covering the intumescent sealant.

[0014] Now referring to FIG. 1, therein is shown a smoke damper according to the invention as seen in the direction of an air duct. The smoke damper comprises a substantially rectangular frame 1 and, adapted therein, mutually parallel aligned slats 2, the number of which in the embodiment illustrated in the drawings is four. The slats are pivotally mounted onto the frame of the smoke damper with the help of shafts 6. In the situation shown in FIGS. 1 and 2, the slats 2 are in their closed position, i.e., shutting off the entire cross section of the air duct, whereby air flow through the smoke damper is prevented. As mentioned earlier in the text, this is the position into which the smoke damper is triggered under a fire situation. A more detailed description of the actuating mechanism of the slats and actuator means thereof may be omitted herein, since such means can be readily implemented using any appropriate technique known in the art.

[0015] As shown in FIG. 2, the long edges of the slats are provided with seals 3, 4 serving to seal the interslat gap when the slats are in their closed position. In FIG. 3 is shown a slat 2 according to the invention in an enlarged scale. The slat is advantageously made of sheet steel so that both long edges 2', 2" of the slat have substantially identical grooves 5 fabricated thereon. The grooves run close to the corners of the slat long edges such that the first long edge 2' has the groove made asymmetrically in regard to the groove of the second long edge 2". Herein, the reference numerals 2', 2" of the slat long edges denote the edge surfaces that are parallel to the slat's axis of rotation. However, the term "slat long edge" does not necessarily imply that the slat edges have to be as long as the end-to-end length of the slat.

[0016] The grooves 5 running along the long edges of the slat are shaped in a conventional fashion so as to make the thick base flange of the rubber seal 3 to seat firmly in the groove. As shown in FIG. 3, the opposite long edge 2" of slat 2 has the bottom space of its groove 5 filled with an intumescent sealant 4. Into the groove 5, onto the intumescent sealant therein, is placed a metallic continuous-section strip 7 advantageously made of the same material as the slat 2 proper. The strip can be readily inserted in place by way of pushing it into the groove via one end thereof. The ends of the slat keep the strip firmly seated. The metallic strip 7 is made substantially V-shaped and placed into the groove so that the tips of the sides of the V-shape strip rest substantially abutting the bottom of the groove as shown in FIG. 3. In this fashion the intumescent sealant 4 remains trapped under the inside surface of strip 7. During normal operating conditions, the metallic strip 7 remains firmly clamped in place by virtue of its ν'-shape. In FIG. 4 is shown the cross section of the metallic strip 7. As illustrated therein, one side 7" of the strip is made slightly wider than the other side 7'. The strip is inserted into the groove into such a position that the narrower side 7' will be aligned closer to the centerline of the long edge 2" of slat 2.

[0017] Grooves 5 are situated close to the corners of edges 2', 2" in such a fashion that, when two adjacent slats face each other by their edges in the closed position of the damper, the elastic seal 3 running along the long edge 2' of one slat meets the long edge of the next adjacent slat on the nongrooved area of the adjacent long slat edge thus sealing the interslat gap and, further, that the groove made on the long edge of said next adjacent slat contains intumescent sealant 4 covered by said continuous-section strip 7 in such a fashion that a gap remains between the covering strip and the nongrooved area of the long edge of the next adjacent slat in a situation where the intumescent sealant has not undergone swelling.

[0018] Accordingly, in a fire situation, the slats 2 are closed whereby their long edges face each other. The initial sealing effect is provided by conventional rubber seals 3 that are pressed against the adjacent slat edge. With increasing temperature, the intumescent sealant begins to swell thus forcing the metallic strip outward from the groove 5. Under the outwardly expelling force, the sides of the metallic strip approach each other, whereby the metallic strip can move slightly outward from the groove 5 and become compressed against the opposed long edge of the adjacent slat. Even after the thermal disintegration of the conventional seal 3, the damper still remains gas-tight by virtue of the metallic strip 7 acting as a compressive seal under the pressure exerted by the intumescent sealant 4.

[0019] To a person skilled in the art it is obvious that the invention is not limited by the above- described exemplary embodiments, but rather may be varied within the inventive spirit and scope of the appended claims. Accordingly, the smoke damper according to the invention need not necessarily have all the slats 2 of mutually identical shape and, furthermore, their structure may be varied from that shown in FIG. 3. For instance, not all slats need be provided with an intumescent seal structure with the provision that a given slat always mates on its both edges with adjacent slats having an intumescent seal structure of the type described above. The outermost slats will be designed appropriately in regard to the design principles discussed herein. The intumescent sealant can be any material known in the art and capable of performing the desired function. The material of the covering strip 7 is selected with regard to the constraint that it must be fire-resistant at least to a certain degree. Also the grooves 5 of the slat edges may be implemented differently from that shown in the drawing. Theoretically the grooves could even be omitted, whereby alternative designs of the intumescent sealant and its covering strip might be contemplated. Obviously the number of slats is neither limited. One or more slats can be used as appropriate. Further obviously, the intumescent sealant and its covering strip may have a design supported to the slat ends while such a construction is not described in greater detail in the drawing and description part of this application.

[0020] The shape and structure of the covering strip may be varied from that illustrated in the drawings. For instance, the strip can as well be a U-shaped continuous-section strip running over the entire length of slat long edge. Obviously, also in this embodiment the intumescent sealant must be placed under the covering strip. A still further possible embodiment comprises clamping the strip by its one side to the slat long edge, whereby the other side can move under the force exerted by the swelling of the sealant.

REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description • Fi 105129 i00031 • GS2259249A f00061 • FI5654 fOOOei • GB1586362A fOOOTl

Claims

A smoke damper comprising a substantially rectangular frame (1) which can be installed in a ventilation air duct, said frame having a tiltably mounted thereto having at least one rotatable slat (2) rotatable by means of a separate mechanism with about 90 ° between an open position and a closed position, the lamina having a first long edge (2 ') and a second long edge (2 ") as the opposing lamina edge relative to the first edge, and the lamina further having an elastic seal (3) attached thereto and a swelling sealing material (4), wherein the elastic seal (4) is fixed at least on the first long edge (2 ') of the slat to extend substantially over the entire length of the slab edge, and wherein the swelling sealant (4) is secured at least to the second edge (2 ") of the slat (2) to extend substantially over the entire length of the slab edge, characterized in that the swelling sealant (4) is covered. t of a strip (7) of continuous cross-section of fire-resistant material capable of moving outwardly from the long lamellar edge under the swelling action of the sealant and the swelling sealant (4) embedded in a groove (5) formed on the second long edge (2 ") and has a continuous strip of metal strip (7) positioned therein to cover the swelling sealant and the cross-section of the strip (7) is substantially V-shaped and the strip is positioned on the swelling sealing material (4) in the groove (5) in such a position that the V-shaped corner edge of the strip is pointing outwards from the groove so that the strip (7) remains clamped in place by its V-shape.

Smoke damper according to claim 1, characterized in that the first long edge (2 ') of the lamella (2) has a groove which is substantially identical to that provided on the second long edge (2 "), and said grooves are positioned close to the corners of the slat edges such that when two adjacent slats face each other with their edges in the closed position of the damper, the elastic seal (3) extending along the long edge of one slat meets the long edge of the next adjacent slat on the non-grooved area of the adjacent long slat edge, thereby sealing the gap between the slats and the groove formed on the long edge of the next adjacent slat containing swelling sealant (4) covered by the strip (7) having a continuous cross-section in such a way that a gap remains between the cover strip and the non-grooved region of the long edge of the next adjacent lamella in a situation where: the swelling sealant has not experienced any swelling.

Smoke damper according to claim 1 or 2, characterized in that the sides (7 ', 7 ") of the V-shaped metal strip (7) of continuous cross-section have different widths and that the metal strip is located in the groove (5) so that it narrower side (7 ') of the V shape is located closer to the center line of the long edge of the slat.