WO2012143598A1

WO2012143598A1 - A smoke flue damper arrangement, a smoke damper module and a method for operating a smoke flue damper

Info

Publication number: WO2012143598A1
Application number: PCT/FI2012/000021
Authority: WO
Inventors: Carl-Gustav Petterson
Original assignee: Ventia Oy
Priority date: 2011-04-20
Filing date: 2012-04-19
Publication date: 2012-10-26
Also published as: FIU20110139U0; FI9582U1

Abstract

The present invention relates to a smoke damper arrangement including a smoke flue portion (1 '), a smoke damper (3) having positions "open" and "closed", an air duct for cooling (12), as well as an air control assembly (20) having a position "open" (A) as well as a position "closed". The air control assembly (20) is arranged for mechanically preventing said smoke damper (3) from taking the position "open" when the air control assembly (20) is in the position "closed" while allowing the air control assembly (20) to take an arbitrary position between positions "open" and "closed" when the smoke damper (3) is the position "closed". The invention also relates to a smoke damper module arranged to constitute an extension of a smoke flue, as well as to a method for controlling the operation of a smoke damper (3).

Description

A SMOKE FLUE DAMPER ARRANGEMENT, A SMOKE DAMPER MODULE AND A METHOD FOR OPERATING A SMOKE FLUE DAMPER

The present invention relates to a smoke damper arrangement including a tubular smoke flue, a smoke damper element arranged to be movable in said smoke flue portion as well as an air channel or duct arrangement surrounding said smoke flue portion and providing cooling air into the vicinity of said smoke flue for insulating said smoke flue portion from any surrounding structures, wherein air control means are arranged for regulating the passage of air into said duct arrangement, said air control means interacting with said smoke damper element and having a position "open" for providing a free passage for air into said duct as well as a position "closed" for closing off said passage.

The present invention also relates to a smoke damper module arranged to constitute an extension of a smoke flue and comprising an end flange, a smoke flue portion extending through said and flange, a smoke damper comprising a smoke damper element movably extending into said smoke flue portion, said smoke damper having a position "open" for maintaining a free passage through said smoke flue portion and into said smoke flue as well as a position "closed" for closing said free passage, a cooling air duct comprising an intermediate space for facilitating a flow of cooling air between said smoke flue and an outer casing surrounding said smoke flue, as well as air control means for regulation the flow of said cooling air, said air control means having a position "open" for maintaining passage(s) for said cooling air into said intermediate space as well as a position "closed" for essentially off said passage for said cooling air into said intermediate space.

The present invention also relates to a method for controlling the operation of a smoke damper in a chimney arrangement comprising at least one smoke flue, at least one smoke damper arranged movably to at least partially close said smoke flue, at least one cooling air duct arranged for providing a flow of cooling air around said smoke flue as well as an air control means for closing said cooling air duct.

A smoke damper constitutes an essential part of a working smoke flue in a chimney. The smoke damper is used for regulating the flow of fluid through said smoke flue and thus, i.a., for preventing warm air from escaping from a room through a fireplace or the like and through a chimney connected thereto, for preventing cold air from descending through said chimney and said fireplace into said room, and, at certain old type furnace arrangements, for regulating the rate of smoke moving upwards through said flue. Thus, when a furnace or other fireplace is in use and heating a room, the smoke damper is maintained, to a suitable degree in accordance with good heating practice, in an open or at least partially open position, but when the heating has ended or other use of the furnace is interrupted the smoke damper may be closed. In this case the process of making a fire in the fireplace starts by opening the smoke damper.

In this context it should be observed that, in practice, smoke and air passages in chimneys often are, to some extent, of a rather coarse finish, and thus such expressions as "closed", "free" and "open" are to be interpreted as indicating the general state in a larger common sense. Thus such expressions should be interpreted to cover approximately 90 to 100%, i.e. when a smoke flue is considered being closed there can still be an opening extending over a 10 % of the theoretical free section area. In fact, many modern smoke damper structures even in a fully "closed" state comprise an opening in order to eliminate misuse due to lack of understanding of the operational principles of furnaces. The expressions used in this context are intended to cover also such deliberate deviations from the technically exact interpretation of the expressions used.

With respect to fire safety the most risky portions of a chimney are where a smoke flue extends through a combustible structure such as a ceiling or a roof. At such locations the smoke flue must be insulated in order to prevent the surrounding structures from overheating. A common method for preventing excessive temperatures at such locations is to use a sufficient amount of incombustible insulation material such as fire resistant heat insulation and/or to conduct cooling air around the flue or between the flue and a chimney mantle or casing surrounding said smoke flue. Especially in cases where the actual smoke flue comprises a tubular structure having relatively thin tube walls made of, e.g., sheet metal, such insulation is of uttermost importance in order to avoid fire in combustible structures surrounding the chimney.

Thus, cooling air is commonly used for preventing surrounding structures from overheating due to the vicinity of hot smoke gases flowing in a smoke flue. For example, cooling air can be conducted already into a smoke chamber in a fireplace. This, however, could have a negative influence upon the draught properties of the fireplace and on the smoke temperature in general. In some cases, as discussed above, cooling air is fed in between a smoke flue tube and an outer mantle and sometimes a layer of insulation is added to the structure. In a three mantle smoke flue arrangement cooling air is often conducted into an air duct extending between the innermost smoke channel tube and an intermediate mantle.

On the other hand, any excess ventilation of cooling air from a room to be heated is counterproductive to the purpose of the heating. Thus, it is common practice to close any unnecessary ventilation ducts when the heating process has come to its end. This closing usually includes closing the smoke damper as well as closing any additional air ducts. For this purpose cooling air channels such as the inlet to the space between the smoke flue and an outer mantle often comprises some kind of closing arrangement, usually a series of opposite openings arranged in two adjacent sheet elements, one of which is movable in relation to the other. When the heating, i.e. the burning process in a fireplace, has ended also the air duct can thus be closed in order to prevent heat from escaping from the room through said cooling air channel.

All the arrangements described above include a risk of misuse. If the flow of cooling air is closed while a heating apparatus is still in operation the portion where the smoke flue runs through a surrounding structure will overheat, which can cause the surrounding structures to catch fire. In order to prevent such misuse WO-publication 2011/124756 A1 suggests a mechanical functional connection between the damper element and means for controlling the cooling air. The proposed arrangement, however, is rather complicated and still has some disadvantages, i.a. the connection prevents an adaptable operation of the cooling air control means. Further, any elements which are directly arranged at a sliding smoke damper are apt to corrode due to the heat impact from the hot smoke, said impact being conveyed via the smoke damper.

The object of the present invention is to eliminate the possibility of such misuse and thus to prevent fire and improve safety, while, at the same time, still facilitating a flexible use of the cooling air duct for heat recovery and/or ventilation purposes. Another object of the present invention is to provide a simple control arrangement comprising a minimum of complicated elements and no elements that will require any special maintenance.

According to the present invention the operation of the smoke damper is mechanically connected to the operation of a closing means for the cooling air duct in a manner which prevents the opening of the smoke damper unless the cooling air duct is open. And vice versa, the cooling air flow cannot be effectively restricted or completely shut off unless the smoke damper is in a closed position. Thus one cannot, without acute smoke problems in the fireplace, positively maintain a fire therein unless cooling air is flowing and prevening the smoke flue from overheating surrounding structures. Of course, a fire can be set, but the direct smoke problems in the vicinity of the fireplace will alert the user to open the cooling air duct, after which the smoke damper can be opened. In no case can the smoke damper be opened without opening the cooling air duct. However, when no active fire is maintained in the fireplace a user can freely choose to keep the cooling air duct open or closed.

According to a favorable embodiment of the present invention a smoke damper is provided as an extension element to a chimney structure comprising a smoke flue and an air duct, i.e. a vacant slot surrounding said smoke flue. Said extension element favorably comprises a bottom flange, a smoke flue portion extending through said bottom flange, and a smoke damper element provided in said smoke flue portion. The arrangement further comprises a fixed first perforated grill portion as well as a movable second perforated grill portion having a perforation corresponding to that of the fixed grill portion. The respective perforation suitably comprise a multitude of holes, slots or the like openings in the respective grill portions. Said second perforated grill portion is arranged to be movable in relation to said fixed first perforated grill portion between a position "closed" where said perforations do not align and a position "open" where said perforations are aligned. In said position "open" the aligned perforations provide an open inlet from an air space such as the surrounding room and into to the lower end of a void space between said smoke flue and a surrounding mantle. The upper portion of said void space is connected to open air or to some arrangement for further processing air which is heated by the hot smoke in the smoke flue and which due to heat convection rises in said void space which thus constitutes a cooling air duct. By bringing said movable second perforated grill portion into a position where said perforations at said first and second perforated grill portions do not align, the inlet at said lower part of the void space is closed, which effectively stops the heat convection, thus preventing cooling air from flowing. This reduces the insulating effect between the smoke flue and any surrounding structures but also prevens heat from escaping.

Now, according to the present invention the arrangement comprises means for forcing a user to avoid mistakes while controlling the positions of the smoke damper and the movable second perforated grill portion, respectively, the arrangement being such that said moving second perforated grill portion cannot be in a position "closed" while the smoke damper is in a position "open". No hot smoke can then pass into the smoke flue unless, at the same time, also cooling air flows around said flue and prevents the surrounding structures from overheating.

Thus, the present invention eliminates the possibilities of such human errors which would not be obvious to the user, who while maintaining a fire in, e.g., a fireplace certainly will observe when the smoke damper is closed but who might not observe a situation where also the cooling air inlet could be closed and cause an imminent risk of fire. However, when no fire is maintained in the fireplace the flow of air through the cooling air duct can be freely controlled to any value between "duct closed" and "duct open", said values included. In this manner the present invention improves security while still not preventing appropriate ventilation through a chimney or an effective retrieval of heat energy. A smoke damper module according to the present invention facilitates the use of thinner additional insulation where the smoke flue leads through roofs, ceilings and insulated structures, and the present invention also provides means for an improved use and recovery of the heated cooling air in a multitude of manners.

The characteristics of the present invention are defined in the appended independent claims 1 , 8 and 9, while favorable embodiments are disclosed in the dependent claims. Thus, the smoke damper arrangement according to the present invention is characterized in that said air control means for regulating said passage of air into said air duct is arranged for mechanically preventing said smoke damper element from taking its said position "open" when said air control means is in its said position "closed" while allowing said air control means to take an arbitrary position when said smoke damper is in its position "closed".

Correspondingly, the smoke damper module according to the present invention is characterized in that said control means for said cooling air comprises a mechanical arrangement for preventing said smoke damper element from taking its said position "open" while said control means for said cooling air remain in its said position "closed" but allowing said control means to take an arbitrary position when said damper is in its position "closed". Further, the method for operating the smoke flue damper according to the present invention is characterized in allowing the cooling air duct closing arrangement to take an arbitrary position while the smoke damper is in its position "closed" but mechanically preventing an opening of the smoke damper while the cooling air duct closing arrangement is in a position "closed".

According to a favorable embodiment of the present invention a smoke flue damper module is characterized in that a movable grill element is arranged so that the movability of the smoke damper is functionally connected to the position of the movable grill in such a manner that the smoke damper can be in its position "open" only when cooling air can access the air duct which separates the smoke flue from any surrounding combustible structures. Favorably this is achieved utilizing mating slits in superimposed first and second grill elements, which slits align to constitute a unitary passage for said damper element through the superimposed grill elements only when also the other openings in said first fixed grill element and said movable second grill element are at least essentially aligned.

The smoke damper module according to the present invention acts as an opening and closing arrangement for the cooling air and the smoke flue which, when a heating device is in use, always safeguards the open passage for cooling air. The heating device cannot be used unless the provision and flow of cooling air has been made possible. Always, when the smoke damper is in its position "open", the smoke damper module according to the present invention will facilitate the provision of cooling air between the hot smoke flue and any surrounding combustive strucures. In addition, the smoke damper module according to the present invention will act as a heat exchanger and heat the cooling air flowing therethrough, whereafter the heated air can be conveyed to a distribution box and/or through suitable channels or some other heat retrieving device and back to a room to be heated and/or a discharge, e.g., directly to rooftop.

Correspondingly, shutting the free cooling air flow will prevent also the use of the fireplace, since in a smoke damper module according to the present invention only a closing of the smoke damper provides a possibility to shut off also the flow of air through the cooling air duct, and, on the other hand, if the smoke damper is closed the fireplace cannot be effectively used in any sensible manner. And vice versa, the smoke damper cannot be opened unless the movable grill portion is moved to its position "open", which operation will initiate the flow of cooling air through the cooling air duct. This flow cannot be closed when the smoke damper is actuated into its position "open", but when the smoke damper is closed any desired flow can still be maintained in the cooling air duct, i.e. all flow values between "full draught" and "no flow".

A main advantage of the smoke damper module in accordance with the present invention relates to safety and to the elimination of any possibilities of misuse while still not restricting the use of the cooling air duct for other purposes, one of which being an effective retrieval of heat energy.

The present invention will now be disclosed in more detail with reference to the appended drawings, wherein

Figure 1 discloses, in an exploded perspective view, a lower portion of a generally tubular smoke damper module arrangement according to one embodiment of the present invention,

Figure 2 discloses the arrangement of Figure 1 in a composed state, where all elements controlling a flow of fluidum are in a position "open",

Figure 3 discloses the arrangement of Figure 2, where all elements controlling a flow are in a position "closed",

Figure 4 discloses, partially in section, an assembled smoke damper module according to a favorable embodiment of the present invention, the arrangement being adapted for a chimney structure comprising at least one tubular smoke flue having a generally circular section,

Figure 5 discloses a lower portion of an alternative smoke damper module arrangement adapted especially for chimney arrangements having a generally rectangular section, Figure 6 discloses still an alternative embodiment wherein a smoke damper plate is turnable around a shaft arranged in a smoke flue, and

Figure 7 shows a movable perforated grill means for the embodiment disclosed in Figure 6.

In a preferred embodiment according to Figure 1 a smoke damper arrangement comprises a lower end flange 2, a tubular smoke flue portion 1 ' extending through said end flange 2, as well as a common smoke damper 3 which is operable, suitably by means of a knob handle 4, to slide between a position "closed" and a position "open". In the position "closed" as shown in Figure 1 a damper plate 5 of said smoke damper 3 extends in a movable manner through a slit in the wall of said tubular smoke flue portion V into the inner thereof and prevents smoke from passing through the flue. Correspondingly, in a position "open" as shown in Figure 2 said damper plate 5 is withdrawn from said flue portion 1 ', thus facilitating a flow of smoke through the flue. When the smoke damper is in the position "open" the smoke flue will function as an exhaust for conducting smoke from a fireplace (not shown) to, e.g., open air. When the smoke damper is in the position "closed" smoke cannot pass through the flue but will fill the room around the fireplace with smoke, the fireplace will malfunction and the user will be alerted.

According to the present invention a smoke damper or smoke damper module further comprises an air control assembly generally indicated as 20, for controlling the flow of cooling air around a smoke flue 1 as disclosed in Figure 4. In the embodiment shown in Figures 1 to 4 said air control assembly 20 comprise a pair of annular perforated grill means such as tubular ring means suitably made of sheet metal and arranged in a coaxial disposition, i.e. a stationary first perforated grill means 6 and a movable second perforated grill means 7 which can be forced to slide in relation to said stationary first perforated grill means 6, suitably by means of a knob handle 8 attached to said movable second perforated grill means 7 and extending to the outside of the air control assembly 20 through an elongated slit 9 arranged in said stationary first perforated grill means 6. Thus, in the disclosed embodiment the movable second perforated grill means 7 is the inner one of said coaxial tubular grill means, but also a contrary arrangement is possible.

Said fist and second perforated grill means 6 and 7 comprise respective perforation such as cooling air openings 10a and 10b which openings can be positioned, by means of a sliding motion turning said movable second perforated grill means, into a superimposed mutual disposition where said openings 10a and 10b are aligned and constitute a multitude of open cooling air intakes 1 1 leading to the interior of said perforated grill means 6 and 7 and to the vicinity of the outside of said smoke flue portion 1 '. When said perforated grill means 6 and 7 are in this mutual disposition, hereafter referred to as position "open" or "A", cooling air can flow through the aligned openings 10a, 10b in said perforated grill means 6 and 7 and into the interior of the grill means assembly, around the smoke flue portion 1 ' as disclosed in Figure 2 and upwards in a cooling air duct 14 along the outside of the smoke flue 1 as shown in Figure 4. Such cooling air flow is indicated by arrows 12. Now, when the fire in the fireplace has burned down and in order to prevent heat from escaping through the chimney structure after heating the smoke damper 3 will usually be forced shut, i.e. the damper plate 5 is shoved into the position "closed" by means of said knob handle 4. In this situation the smoke flue 2' does not require cooling, and thus also a closing of the cooling air flow through the air duct can be allowed. In the smoke damper module shown in Figures 1 to 4 this is achieved by sliding the movable annular perforated grill means 7 into such a position in relation to the stationary annular perforated grill means 6 where said openings 10a and 10b do not align, which position is disclosed in Figure 3. Now the cooling air intakes 1 1 are shut (indicated by a reference 1 1 x) and no heat escapes via the cooling air duct 14 enclosing the outside of the tube which constitutes the smoke flue 1. However, for ventilation and/or heat recovery purposes or the like, an air flow can still be maintained, i.e. the air control assembly 20 can freely be put into any position between "open" and "closed", in accordance with, e.g., the user^'s preferences.

However, especially a thin walled smoke flue 1 made of, e.g., sheet metal could drastically overheat if one should start firing the fireplace when the cooling air flow is closed, and for safety reasons this must be avoided, preferably to such an extent that no human mistakes can occur. This, on the other hand, is automatically achieved by means of the arrangement according to the present invention, since the smoke damper plate 5 cannot be forced into a position "open" unless also the cooling air control means are in a corresponding position "open" or "A", i.e. a position where said openings 10a and 10b are aligned to constitute said air inlets 1 1 . This function is commenced by means of oblong openings or slits 13a, 13b which are arranged in a similar manner in said first and second grill means 6 and 7, respectively. When said grill means 6, 7 are in the mutual disposition "open" also these slits 13a and 13b are aligned and constitute a passage for said damper plate 5. In any other mutual disposition of said grill means 6, 7, however, said slits 13a and 13b do not align, and thus the passage of the damper plate 5 is prevented. In this position the damper cannot be opened and no fire can be maintained, in any appropriate manner, in a fireplace connected to the smoke flue 1 .

Figure 2 discloses a situation where said smoke damper 3 is in the position "open". Here the smoke damper plate 5 is withdrawn from the smoke flue portion 1 ' which, in accordance with the present invention, has been possible only when the perforated movable second grill means 7 has already been brought into a corresponding position "open" which in the Figures is indicated as "A". In this position "A" said openings 10a and 10b, as well as said slits 13a and 13b are aligned, respectively, thus providing a passage through the superimposed grill means 6, 7 for the damper plate 5 as well as approbate open inlets 1 1 for cooling air 12. Thus, positioning the movable second grill means 7 in the position "open" or "A" in relation to the fixed first grill means 6 at the same time opens the cooling air inlet and provides an opening for the damper 3. The damper plate 5 can now be withdrawn from closing off the smoke flue 1 and a fire can be safely maintained, in an appropriate manner, in a furnace or other fireplace, while cooling air 12 can flow through said cooling air duct 14 arranged around the smoke flue 1 , as shown in Figure 4.

When the frist and second perforated grill means 6 and 7 are in this mutual disposition and the damper 3 is withdrawn from the smoke flue portion 1 ' smoke 15 generated in the fireplace can leave through the smoke flue 1 , while cooling air 12 flowing in the cooling air duct 14 will act, at the same time, as a heat insulation for said smoke flue 1. This cooling air 12 will be heated by the hot outer surface of the smoke flue 1 , will flow upwards in the cooling air duct 14 and will finally leave the chimney structures as warm air 16. This warm air 16 can be conveyed into open air or brought forward to some suitable heat recovery procedure.

Further, when the smoke damper plate 5 is withdrawn from the smoke flue portion Γ and at least partially out through the aligned slits 13a and 13b the smoke plate 5 locks the alignment and hence also the movable second perforated grill means 7 and thus the arrangement prevents a user from bringing the movable second perforated grill means 7 into a position "closed", in Figure 3 indicated as "K", which would close the cooling air inlet 1 1. The movable second perforated grill means 7 cannot be moved until the smoke damper 3 has been manually closed by pushing it back into the smoke flue portion 1 ' and away from blocking the passage constituted by the aligning slits 13a and 13b. This manual closing will be done only when the fire has burnt out and no hot smoke flows through the smoke flue 1 which then does not need any additional cooling.

Figure 3 now discloses the situation when the smoke damper 3 is in the position "closed". When the smoke damper is fully closed, i.e. the smoke plate 5 is pushed all the way into the smoke flue portion 1 ' the smoke damper plate 5 leaves the aligned slits 13a and 13b and now also the movable second perforated grill means 7 can be brought into its position "closed" as shown in Figure 3 and indicated as "K". Now said openings 10a and 13a, respectively, in said fixed first perforated grill means 6 and said openings 10b and, said 13b, respectively, in said movable second perforated grill means 7 do not align anymore and the damper plate 5 cannot be withdrawn from the smoke flue portion V. Figure 3 shows that a part 13x of the movable perforated grill means 7 adjacent to the slit 3b will overlap with a part of the open area of the slit 13a and thus restrict the open area of the aligning slits 13a and 13b to such an extent that the relevant portion of the smoke damper plate 5 cannot extend through the slit. Now the smoke damper 3 cannot be opened. At the same time the flow of cooling air through the air duct 14 is prevented so that no heat will escape unless the user purposefully opens the cooling air passages 1 1.

A handle 8 is favorably arranged at said movable second grill means 7 in order to move it between positions "open" and "closed" (positions "A" and "K", respectively). In the embodiment disclosed in Figures 1 to 4 said first perforated grill means 6 is an annular means inside which said movable second perforated grill means 7 is arranged, in the shape of similar annular means, in a movable manner, i.e. turnable in the directions of the arrow shown in Figure 3. Here said handle 8 extends out through said elongated slit 9 which is arranged in the fixed first perforated grill means 6 which here constitutes an outermost part of the air control assembly 20.

Figures 1 to 3 show how said fixed perforated first grill means 6 and said movable perforated second grill means 7 comprise passage slits 13a and 13b, respectively, arranged for providing passage for the smoke damper 3. When said movable perforated second grill means 7 is in the position "open" said passage slits 13a and 13b are aligned and enable said smoke damper 3 to pass through (see Figure 2) but said slits 13a and 13b do not align (see Figure 3) when said movable second perforated grill means 7 is in the position "closed", and this prevents the smoke damper 3 from passing through. Thus, said smoke damper 3 can be brought, suitably by means of said knob handle 4, into its position "open" only when said movable second perforated grill means 7 is its position "open" (see Figure 3).

As shown in Figure 4 a smoke damper module according to the present invention is suitably fitted as an extension of a three wall smoke flue 1 having an inner tubular smoke flue 2 and an outer tubular structure 17 which in the disclosed embodiment comprises an insulation separated from the smoke flue by an air duct 14 for cooling air 12. In use the smoke damper 3 is opened by moving the movable second perforated grill means 7, by means of said handle 8, into its position "open" (to "A") and thereafter pulling out the smoke damper 3 by means of said knob handle 4, which brings about the situation shown in Figure 2. In this position of the different elements cooling air has free access 12 to the vent arrangement constituting said cooling air duct 14 and the smoke gas has free access to the smoke flue 1. The smoke damper 3 can be closed by pushing the smoke plate 5 inwards by means of said knob handle 4 after which the movable second perforated grill means 7 can be turned by means of said handle 8 into the position "closed" in order to reach the situation disclosed in Figure 3.

In this manner the points where the smoke flue 1 leads through other structures (not shown) said structures are cooled by means of cooling air 12 because usually a flowing air is the most efficient insulation. However, usually it is impossible to control air flows in a safe manner and thus a major part of energy already fed to a room is wasted by a continuous air leakage. One object of the present invention is to provide a solution for the elimination of such leakage where it is unnecessary.

The smoke damper 3 is usually used for closing off the chimney from the fireplace and in this way produced heat energy can be saved by preventing heat from escaping through the smoke flue 1 or, correspondingly, by preventing cold air from descending via the fireplace in into the room.

One benefit of the present invention is the possibility to cool the chimney's lead through points in a controlled manner and thus to make the lead through structures safer and less space consuming while, at the same time, making good use of the heat energy contained in the exhaust air 16 which has been used for cooling purposes and which thus has been heated.

A smoke flue module in accordance with the present invention can be used in connection with masonry chimneys, block chimneys, segment chimneys and steel tube chimneys. Cooling air 12 can be conveyed to the cooling air duct 14 when the smoke damper 3 is in its position "open" only, or otherwise when a user considers ventilation appropriate. The movable second perforated grill means 7 is brought into the positions "open" / "closed" suitably by moving the grill means 7 by means of the handle 8. When the smoke flue module^'s handle 8 is in the position "closed" the movable second perforated grill means 7 is also in its position "closed" or "K", whereby it also locks the smoke damper 3 to the position "close" and prevents both smoke gases from flowing in the smoke flue 1 and cooling air 12 from flowing in the cooling air duct 14.

A smoke damper module according to the present invention controls an air cooled chimney. In the the embodiments disclosed in Figures 1 to 4 such a chimney is a steel tube chimney of a tubular shape, but the smoke damper module according to the present invention will also, in the same manner, function in connection with chimneys having a different structure and/or a different shape, such as block chimneys or other chimneys having an essentially rectangular cross section. Also in this case a smoke damper module according to the present invention favorably interacts with a smoke flue 1 having a separate mantle 17 so that the arrangement constitutes an air cooled chimney controlled by the smoke damper module in accordance with the present invention.

For chimneys having a rectangular cross section a separate adapter can be used, or the smoke damper module as such can have a rectangular cross section. Thus, Figures 5 and 6 discloses embodiments wherein said fixed and movable perforated grill means are arranged not as superimposed tubular rings but as adjacent planar grill means 6', T arranged in a subsequent manner. Also in these embodiments the function corresponds to the one disclosed with reference to Figures 1 to 4. The embodiment disclosed in Figure 6 comprises not a slidable smoke damper 3 but a smoke damper arranged as a smoke damper plate 5' which extends solely in the smoke flue 1 and is turnable around a rotatable transversal shaft 18. In this embodiment a smoke damper control lever 19 connected to said rotatable shaft 18 suitably extends through adjacent slits 13a' and 13b' provided in said first and second perforated grill means 6', 7', respectively, which slits constitute an elongated opening for said control lever 19 only when said grill means 6' and 7' are in such a mutual disposition where the perforations 10a, 10b align to constitute said open cooling air intakes 1 1.

Functionally the inventive arrangement constitutes a special application of a sliding block guidance traditionally known especially in connection with the operating of certain mechanical machine elements. In the inventive arrangement, however, the smoke damper 3 or some of its elements such as the smoke damper plate 5, 5' and/or the control lever 19 will, as such, constitute a sliding guidance block or "stone". Correspondingly, a part of the perforation 13a, 13b or 13a', 13b' arranged in the mutually movable overlapping perforated grill means 6' 6' and 7, 7', respectively, will constitute and define the sliding guidance path. In the embodiments disclosed above certain pre-defined mutual locations of the perforated grill means 6, 6' and 7, are achieved by manually operating the handle 8 which, in turn, provides a clearly defined path or passage for the smoke damper 3 and/or its elements such as the smoke damper plate 5 or the lever 19. In another embodiment this positioning can be achieved using some other control means such as, e.g., electric or pneumatic power, a movement based on temperature differences or the like non-manual actuation. In any case, the guidance slit provided will receive the element which consitutes the sliding guidance block and force the desired co-operation between the different elements, i.e. the smoke damper 3 and the perforated grill means 6, 6' and 7, 7' constituting the air control assembly 20 for regulating the flow of cooling air 12 around the hot smoke flue 2.

Claims

1. A smoke damper arrangement including a smoke flue or a portion thereof (1 , 1 '), a smoke damper (3) including a smoke damper plate (5, 5') and having a position "open" for maintaining a free; smoke passage through said smoke flue and a position "closed" for closing said smoke passage, an air duct arrangement (14) for providing a flow of cooling air (12) into the vicinity of said smoke flue (1 , 1 '), as well as an air control assembly (20) for regulating a passage (1 1 ) for air into said duct arrangement (14), said air control assembly (20) having a position "open" (A) for providing a free air passage (1 1 ) for conducting cooling air into said duct (14) as well as a position "closed" (K) for closing off (1 1 x) said air passage, c h a r a c t e r i z e d in that said air control assembly (20) for regulating said air passage (1 1) for cooling air into said air duct (14) is arranged for mechanically preventing said smoke damper (3) from taking its said position "open" when said air control assembly (20) is in its said position "closed" (K) while allowing said air control assembly (20) to take an arbitrary position between said positions "open" and "closed" when said smoke damper (3) is in its position "closed".

2. A smoke damper arrangement as disclosed in claim ^ c h a r a c t e r i z e d in that said air control assembly (20) comprises a first perforated grill portion (6, 6') as well as a movable second preforated grill portion (7, 7') arranged in a superimposed disposition in relation to said first perforated grill portion (6, 6') and arranged to be movable, in relation to said first perforated grill portion (6, 6') into a mutual position "open" (A) where the perforations (10a and 10b, respectively) in said first and second perforated grill portions (6, 6' and 7, 7', respectively) align to constitute open passage(s) (1 1 ) for air through said grill portions (6, 6', 7, 7') and, on the other hand, into a mutual position "closed" (K) where such a flow of air is essentially prevented, where the movement of said smoke damper (3) or said smoke damper plate (5) is mechanically prevented when said movable perforated grill means (7, 7") prevails in its position "closed" (K), favorably so that any movement which would bring said movable perforated grill means (7, 7') into its position "closed" (K) is mechanically prevented as long as said smoke damper (3, 3') or said smoke damper plate^; (5, 5') remains in its position "open".

3. An arrangement as defined in claim 2, c h a r a c t e r i z e d in that where said first and second perforated grill portions (6, 6', 7, 7') constitute a sliding block guide arrangement where said smoke damper (3), said smoke damper plate (5, 5') itself and/or a smoke damper lever (19) constitute a sliding block extending in co-operating slits (13a, 13b, 13a', 13b') arranged in said first and second perforated grill portions (6, 6', 7, 7').

4. A smoke damper arrangement as disclosed in claim 3, c h a r a c t e r i z e d in that said fixed first perforated grill means (6, 6') and said movable second perforated grill means (7, 7'), respectively, both comprise mating openings (10a, 10b) for constituting said cooling air inlets (1 1 ) as well as mating slits (13a, 13a', 13b, 13b') for constituting said passage for said smoke damper (3), said smoke damper plate (5, 5') or a smoke damper control lever (19), where said mating slits (13a, 13a', 13b, 13b'), respectively, are mutually aligned to allow said smoke damper (3) to take a position "open" only when said movable second perforated grill means (7, 7') is in its position "open" (A) where said mating openings (10a, 10b) align to constitute said air inlets (1 1 ).

5. A smoke damper arrangement as disclosed in any one of claims 2 to 4, c h a r a c t e r i z e d in that said movable second perforated grill means (7) is an annular means which is arranged within a likewise annular fixed first perforated grill means (6), favorably so that said movable grill means (7) comprises a handle (8) which extends through a slot (9) arranged in said fixed grill means (6) for moving said movable grill means (7) between a position "open" (A) and a position "closed" (K).

6. A smoke damper arrangement as disclosed in any one of claims 2 to 4, c h a r a c t e r i z e d in that said first and second perforated grill means (6', 7') are planar plate means arranged in a superimposed disposition where said mating slits (10a', 10b') are in an aligned mutual disposition for constituting said air passage (1 1 ) when said air control assembly (20) is in a position "open" (A) and, correspondingly, remain in a non- aligning mutual disposition (1 1x) when said air control assembly (20) is in a position "closed" (K).

7. A smoke damper arrangement as disclosed in any one of claims 1 to 6 c h a r a c t e r ! z e d in that it adapts to a separate adapter for connecting the smoke damper arrangement to a chimney having a rectangular cross section.

8. A smoke damper module arranged to constitute an extension of a smoke flue (1 ) and comprising ah end flange (2), a smoke flue portion (1 ') extenting through said end flange (2), a smoke damper (3) comprising a smoke damper plate (5, 5') movably extending into said smoke flue portion (1 '), said smoke damper (3) having a position "open" for maintaining an essentially free passage through said smoke flue portion (V) and into said smoke flue (1 ) as well as a position "closed" for essentially closing said free passage, a cooling air duct comprising an intermediate space (14) for facilitating a flow of cooling air (12) between said smoke flue (1 ) and an outer casing (17) surrounding said smoke flue (1 ), as well as an air control assembly (20) for regulating the flow of said cooling air (12), said air control assembly (20) having a position "open" (A) for maintaining passage(s) (1 1 ) for said cooling air (12) into said intermediate space (14) as well as a position "closed" (K) for essentially shutting (1 1 x) off said passage (1 1 ) for said cooling air (12) into said intermediate space (14), c h a r a c t e r i z e d in that said air control assembly (20) for said cooling air comprises a mechanical arrangement for preventing said smoke damper (3) from taking its said position "open" while said air control assembly (20) for said cooling air remains in its said position "closed" (K) but allowing said air control assembly (20) to take an arbitrary position between said positions "open" and "closed" (A and K, respectively) when said smoke damper (3) is in its position "closed".

9. A method for controlling the operation of a smoke damper (3) in a chimney arrangement comprising at least one smoke flue (1 ), at least one smoke damper (3) arranged movably to at least partially close said smoke flue (1 ), at least one cooling air duct (14) arranged for providing a flow of cooling air (12) around said smoke flue (1 ) as well as an air control assembly (20) for closing said cooling air duct (14), c h a r a c t e r i z e d in allowing said air control assembly (20) for closing said cooling air duct (14) to take an arbitrary position between positions "open" (A) and "close" (K) while the smoke damper (3) is in its position "closed" but functionally preventing an opening of the smoke damper (3) while the air control assembly (20) closing said cooling air duct (14) arrangement remains in a position "closed".

10. A method as disclosed in claim 9, c h a r a c t e r i z e d in guiding the respective positions of said smoke damper (3) and said air control assembly (20) as a shape controlled force guiding action based on the mutual disposition of superimposed guiding slits (13a, 13b, 13a', 13b') arranged in first and second perforated grill means (6, 6', 7, 7') of which at least one perforated grill means (7, 7') is arranged in a movable manner along the surface of another perforated grill means (6' 6'), wherein said smoke clamper (3), a smoke damper plate (5, 5') and/or a smoke damper lever (19) is allowed to move, within the scope of mating overlapping portions of said guiding slits (13a, 13b, 13a', 13b'), into a position "open" when the mutual disposition of said perforated grill means (6, 6', 7, 7') cause mating openings (10a, 10b) arranged therein to constitute a passage (1 1 ) for cooling air into said air duct (14). (57) Summary

The present invention relates to a smoke damper arrangement including a smoke flue portion (1 '), a smoke damper (3) having positions "open" and "closed", an air duct for cooling (12), as well as an air control assembly (20) having a position "open" (A) as well as a position "closed". The air control assembly (20) is arranged for mechanically preventing said smoke damper (3) from taking the position "open" when the air control assembly (20) is in the position "closed" while allowing the air control assembly (20) to take an arbitrary position between positions "open" and "closed" when the smoke damper (3) is the position "closed".

The invention also relates to a smoke damper module arranged to constitute an extension of a smoke flue, as well as to a method for controlling the operation of a smoke damper (3).

Fig 2