WO2013160776A1

WO2013160776A1 - Intumescent material fire stop device

Info

Publication number: WO2013160776A1
Application number: PCT/IB2013/051840
Authority: WO
Inventors: Giorgio RAMORINO; Paolo DAMIOLI; Corrado MASSARI; Andrea SBICEGO; Gabriele Vitali
Original assignee: Marvon S.R.L.
Priority date: 2012-04-24
Filing date: 2013-03-08
Publication date: 2013-10-31
Also published as: ITBS20130032A1; ITMI20120687A1

Abstract

An intumescent material fire stop device (1), comprising a support body (2) shaped so as to take a collar-like shape around an axis (A) and to define an opening (24) intended to house a pipe (T), an expandable element (3), made up of at least one intumescent material and positioned in the support body (2), and one or more foldable fin (30) joined to the support body (2) by at least one respective hinge portion (33) along a radially inner peripheral edge (22) of said opening (24). Due to the expansion of the expandable element (3), the fins (30) are movable between an initial position, in which the fins (30) are substantially parallel to each other and not intercepting said opening (24), to a closing position, in which the fins (30) converge towards the axis (A) to close at least partially the opening (24). Advantageously the expandable element (3) is made of at least one first intumescent material, expandable at temperatures equal to or greater than a first activation temperature T₁, and at least one second intumescent material, expandable at temperatures equal to or greater than a second activation temperature T₂ higher than said first activation temperature T₁. The first intumescent material and the second intumescent material are axially staggered.

Description

INTUMESCENT MATERIAL FIRE STOP DEVICE

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DESCRIPTION

Field Of The Invention

The . present invention relates , to an intumescent material fire stop device, particularly for applications in the environment security field.

The present application claims the priority of Italian Patent Application MI2012A000687 filed the 24th of April 2012.

State of the Art

An intumescent material fire stop device comprises, generally, a support body, usually made of metal and collar-like shaped and containing a fire resistant intumescent material expanding under the effect of the heat. These devices are fastened to walls or floors at the crossing points of plastic pipes, such as air recirculation pipes or water inflow/ outflow pipes. In particular, the device is positioned around the pipe, or fit on it so as to wrap around a part thereof and, in the event of fire, it is intended to restore the wall or floor fire resistance and, accordingly, of the environment.

When there is a fire in the room, usually the pipes are prone to break, particularly the plastic pipes, for example PVC, that collapse on reaching the respective softening temperature. The device automatically starts up to create a fire barrier and to prevent the spread to other rooms through the rest of the pipe.

In practice, these devices have the function of preventing the fire from spreading through the piping that actually act as a "bridge" among several rooms of a building .

Physically the barrier is formed by the intumescent material put inside the device. On reaching a specific activation temperature, the intumescent material expands, obstructing the passage formed by the pipe section where the device is assembled.

Various intumescent material fire stop devices are known .

The German Patent Application DE-A-10043430 describes a collar-shaped device, provided with a rigid housing where can be housed a pipe extending through an opening in a wall. A plurality of rigid, substantially triangle-shaped, locking lamellar elements is constrained to the collar by means of flexible hinges. At the beginning, the locking lamellar elements are parallel to the outer surface of the pipe, i.e. to its axis. In the housing there is the intumescent material, packaged in bags and arranged in abutment against the locking lamellar elements. The arrangement is such that the pipe, the locking lamellar elements and the intumescent material are radially stacked up from the inside to the outside. In particular the locking lamellar elements are in abutment against the pipe outer surface (fig. 1) . Under the effect of the pressure of the expanding intumescent material, in case of fire, the flexible hinges fold and the locking lamellar elements are radially pushed towards the inside of the space previously filled by the pipe. In this way a barrier is formed, constituted by the intumescent material and the locking lamellar elements approaching to each other to form a disc intercepting more than 50% of the collar front surface.

The Utility Model DE 20 2004 004605-U1 discloses a solution substantially corresponding to two collars similar to the collar described in DE-A-10043430, arranged axially staggered on a single pipe, in any case inside a wall or floor. In the corresponding initial position, the distance between the centers of the two collars is such that the respective locking lamellar elements are almost inserted in each other (fig. 3) and in the corresponding final position they form corresponding discs facing each other, parallel one to another, detached from the expanded intumescent material (fig. 2). A conceptually similar solution is described for example in DE-A-19600369.

The European Patent Application EP 0506497 discloses another solution according to the known art, and conceptually similar to the preceding, in which the locking lamellar elements are shaped as the elements of a camera shutter and they operate substantially like the latter (fig. 1 - fig. 5) .

Another solution known in the art is disclosed in DE-

A-2947593.

The Applicant found that, in general, known devices are likely to offer room for improvement, in particular in terms of effectiveness and reliability.

For example, the known devices are subjected to scattering of the intumescent material, especially if they are fastened to the ceiling; the loss of the intumescent material may compromise the device effectiveness, leaving gaps wherein the fire may spread.

In known devices, during the corresponding expansion, the intumescent material may overstep the locking lamellar elements getting at least partially between them and the pipe and causing an additional drawback. When it happens, this results in the locking elements not completely closing on each other, involving a barrier fire resistance lower than in case of trouble-free operation.

In many countries, according to standards ruling this technical field (in Italy UNI EN 1366), in order to obtain the certification of the device, it is not required to carry out tests using pipes with a specific thickness. In other words, the fire collar manufacturers are not forced to carry out tests on pipes with large thickness having, material being equal, a higher heat resistance with respect to pipes with small thickness. Many manufactures carry out only the tests on PVC or other polymer pipes having a thickness equal to or lower than 5 mm to obtain the certification for their collar. This helps passing the tests, because to move the locking lamellar elements in the pertaining closing position, overtaking the softening material resistance of the pipe, the intumescent material has to apply a pressure definitely lower than the pressure required to get the same result if the pipe is made of a loaded polymer and/ or if it is a large thickness pipe, for example more than 6 mm.

Therefore, the Applicant believes it is necessary to offer a solution able to operate even with large thickness piping, made of loaded polymers.

Summary Of The Invention

An object of the present invention is to provide an intumescent material fire stop device improved with respect to known solutions, being particularly effective and reliable, both for small thickness pipes and for large thickness pipes, and at the same time easy to manufacture and install.

Therefore, a first aspect of the present invention relates to an intumescent material fire stop device according to claim 1.

In particular, the device comprises:

- a support body shaped so as to take a collar-like shape around an axis A and to define an opening intended to house a pipe to be made safe, and

an expandable element, made up of at least an intumescent material, positioned in the support body, and

- one or more foldable fins joined to the support body by at least one respective hinge portion along a radially inner peripheral edge of the opening.

Due to the expansion of the expandable element, the fins are movable between an initial position, in which the fins are substantially parallel and not intercepting the opening, to a closing position, in which the fins converge towards the axis A to close at least partially the opening.

In other words, as a result of the thrust applied by the intumescent material element the fins can move to intercept the opening, namely to obstructs the hole or the opening housing the tube, and to prevent the fire from spreading .

Advantageously the expandable element is made of at least one first intumescent material, expandable at temperatures equal to, or greater than, a first activation temperature ΊΊ, and at least one second intumescent material, expandable at temperatures equal to, or greater than, a second . activation temperature T₂ higher than the first activation temperature Ti (T₂ > ΊΊ.) .

In other words, the first intumescent material is more responsive to heat and therefore it expands earlier than the second intumescent material, that has, in its turn, lower heat reactivity and a higher mechanical resistance against heat.

This arrangement allows the regulation to a certain extent of the expansion kinetics of the expanding element, in the meaning that with the proper selection of the various intumescent materials during the device assembly, it is possible to achieve the desired activation sequence of the intumescent materials during use, that is an initial expansion of part of the expanding element and a final expansion of the whole of the expanding element; accordingly, it is also possible to regulate in advance the thrust applied on the fins over time so as to assure a complete, or almost complete, closing of the port inside the device left clear by the pipe softened or melted by the fire .

This allows maximizing the device effectiveness and the thrust applied on the fins, even though the pipe carrying the device is a large thickness pipe, for example of 10 mm.

The first intumescent material and the second intumescent material are shaped as annular sleeves axially staggered with respect to the axis A. The first intumescent material is placed in correspondence of the hinge portions of the foldable fins. This feature appears to be extremely advantageous for the following reasons.

During use, the fire stop device is assembled so as to have the first intumescent material facing the space where the blaze develops, namely facing the fire. The first intumescent material activates before the second intumescent material and any other possible intumescent materials, making the fins start rotating on respective hinge portions without the risk of the other intumescent material overstepping the fins and penetrate between the fins and the pipe. Accordingly, the first intumescent material is able to push the fins in abutment against the pipe to recover any clearance, before the other intumescent materials can penetrate between the pipe and the fins, causing a detrimental partial closing of the fins themselves .

Preferably the second intumescent material is placed at the side of the second intumescent material with respect to axis A, on the opposite side with respect to the hinge portions. Any other intumescent materials defining the expandable element are placed adjacent to each other in sequence, as corresponding sleeves, or ring-shaped objects.

In the preferred embodiment, the expandable element is housed in a respective annular seat defined in the device support body. The seat extends in a radial direction between the fins and a lateral wall of the support body, such as a cylindrical outer wall, and in an axial direction between a bottom wall and a front wall, opposed and facing each other, and substantially perpendicular to the lateral wall. The expandable element is placed in abutment against the fins, or rather at least the first intumescent material is in abutment against the fins. Advantageously, the expandable element and the lateral wall define therebetween a first interstice, or external air gap, intended to aid the initial expansion of the first intumescent material such that it penetrates at least partially between the second intumescent material and the lateral wall and pushes the second intumescent material towards the fins, during the expansion.

In this embodiment, in practice, an annular chamber is provided around the second intumescent material, allowing the first intumescent material to penetrate, and push the second intumescent material towards the fins before it starts its expansion. The second intumescent material is therefore moved in a very real sense as near as possible to the fins, already tilted on the pipe due to the first intumescent material expansion, resulting in a maximization of the thrust later applied by the second intumescent material during the respective expansion.

The postponed activation of the various intumescent materials avoids drops of the thrust onto the fins. In this way, it is provided an efficient operation of the device, that is able to completely close the fins even in case of a large thickness pipe made of loaded polymers, and in case of the softening thereof being incomplete or time- consuming .

Preferably, between the fins and the opening wherein the pipe is inserted, a second interstice or inner air gap is defined, operating to aid the initial expansion of the second intumescent material such that the moment applied to the hinge portions can be maximized and the closing of the fins can be facilitated. Basically, the air gap acts as a kind of balancing chamber to aid the initial expansion of the first intumescent material and meanwhile to prevent this one or other materials of the expandable element from bypassing the fins and interposing between the fins and the pipe, causing a closing delay of the fins or even an incomplete closing.

Preferably the device comprises a plurality of foldable fins arranged around the opening and angularly spaced apart from one another along the radially inner peripheral edge.

Preferably the hinge portion is shaped so as to allow the fin to fold with respect to the front wall around a rotation axis substantially perpendicular to the axis A.

For example, in the respective initial position the fins project axially, overhanging from the radially inner peripheral edge of the front opening so as to be parallel to the pipe carrying the device.

In an embodiment each fin is substantially triangle- shaped, or spearhead-shaped, optionally with curved vertices and/or sides.

Preferably the hinge portion is plastically deformable .

In a preferred embodiment the support body is made at least partially of a metal material, for example a zinc- plated iron, provided with a powder coating applied by an electrophoresis, for example cataphoresis , painting process .

Preferably at least one of the afore mentioned annular sleeves is formed by coiling a band of the corresponding intumescent material, or is made of strips of the corresponding intumescent material, that are wound overlapping each other. The described arrangement provides the advantage that the fire-heated air penetrates in the interstices between intumescent material layers, for example among the strips, heating almost uniformly both the sleeve periphery and the core, aiding an uniform expansion of the whole mass.

The Applicant reserves the right to file a divisional patent application of a device having the characteristics described in claim 1, differing in that instead of comprising two or more sleeves made of different intumescent materials, the sleeves may be made of the same intumescent material and the desired activation sequence thereof is achieved by the examination, for each sleeve, of the suitable sizes and geometric characteristics, for example width, thickness, thickness of each band, number of coils, etc. and/ or by the addition to the sleeves of additives altering the behavior in case of heat exposure.

In a second aspect, the invention relates to a method according to claim 17, for restricting or preventing the fire spread through a plastic pipe.

Particularly the method comprises the sequential steps of:

a) placing around the pipe a fire stop device according to the present invention, leaving an air gap between the pipe outer surface and the fins, and fastening the device to a wall or to a floor, with the first intumescent material facing the opposite side of the wall or floor, or rather facing the fire;

- allowing, at the beginning, the first intumescerit material to expand into the outer air gap, so as to wrap at least partially the second, not expanded, intumescent material, and towards the fins, pushing the fins to abut against the pipe, the latter being in case subjected to softening, when the air in the environment in which the device is located reaches the first temperature ΊΊ;

- allowing the second intumescent material to expand in order to apply, along with the first intumescent material, a thrust onto the fins up to move them to the closing position, when the environment air reaches the second temperature T2;

- completing the expansion of the expandable element for sealing the pipe or what is left of it.

List of the figures

Further characteristics and advantages of the present invention will be more evident from a review of the following specification of a preferred, but not exclusive, embodiment, shown for illustration purposes only and without limitation, with the aid of the attached drawings, in which:

figure 1 is a perspective schematic view of an intumescent material fire stop device according to the present invention;

- figure 2 is a perspective view of an enlarged detail of the device shown in figure 1;

- figure 3 is a front view of the device shown in figure 1, in two operating conditions (respectively illustrated on opposite sides of a median axis) ; - figures 4 and 5 are perspective schematic views, with parts removed for clarity, of respective modifications of the fire stop device shown in figure 1, in the operating condition corresponding to that shown in the right portion of figure 3;

- figure 6 is a perspective vertical section view of the device shown in figure 4, in a first use arrangement;

- figure 7 is a vertical section view of the device shown in figure 6, in a first use arrangement;

- figure 8 is a vertical section view of the device shown in figure 6, in a second use arrangement;

- figure 9 is a vertical section view of the device shown in figure 6, in a third use arrangement.

Detailed description of the invention

Referring to the accompanying drawings, an intumescent material fire stop device 1, according to the present invention, comprises a support body 2 and an expandable element 3, made of at least one intumescent material and positioned in the support body 2.

The support body 2 is collar-like shaped about an axis

A so as to be arranged, in use, around a pipe T coming out from a wall or floor; in use, the pipe axis is the axis A itself, that is to say that the body 2 and the pipe are coaxial. For example, the pipe is made of PVC .

In the non-limiting example illustrated in the accompanying drawings, the support body 2 is a substantially annular body, in particular made of metal, formed by two opposed substantially C-shaped half-annular elements 5, the elements 5 being hinged to each other by way of a hinge, or a specific mechanical folding system 6 allowing the elements 5 to rotate about an axis parallel to the axis A, and being provided with hooking members 7 diametrically opposite to the hinge 6, to close the body 2 about the axis A.

Let it be clearly understood that the body 2 can be of other kind, being formed, by way of example, by a plurality of sectors foldable with respect to each other, so as to take always a collar shape about a pipe.

The body 2 has an inner hollow 10 for the insertion of the pipe, and it extends along the axis A between two axially opposed ends 11, 12, and it has a lateral wall 13 extending about the axis A and delimiting the hollow 10; the lateral wall 13 is provided with an annular seat 14 housing the intumescent material element 3, that is to say expandable when subjected to fire heat; the seat 14 is defined, besides the lateral wall 13, by a bottom wall 15 and a front wall 16, opposite and facing each other and substantially perpendicular to the lateral wall 13 and projecting from respective axially opposite edges of the lateral wall 13 towards the hollow 10 and the axis A.

In the illustrated case, the lateral wall 13, the bottom wall 15 and the front wall 16 are formed by respective wall portion pairs complementary to the two half-annular elements 5.

The end 11 of the body 2 is provided with a fastening system 17 to fasten the device 1 to a wall; in the illustrated example, the end 11 has a radially outer flange 18 provided with openings 19 to insert fastening members (not shown) such as screws and plugs.

The ends 11, 12 form, respectively, a connecting end ^' 11 and a free end 12 of the device 1, axially opposite to each other. The free end 12 is intended to overhang from the wall where the device is fastened.

The ends 11, 12 have respective peripheral radially inner edges 21, 22 respectively formed on the bottom wall 15 and on the front wall 16, respectively defining a rear opening 23 opposite and substantially in line with a front opening 24, both openings of the hollow 10.

More simply, the hollow 10 is substantially toroidal, so as to allow a pipe to be housed therein, inserted from the bottom wall 15 and the front opening 24.

In the embodiment shown in figures 1-3, the radially inner peripheral edge 22 of the front opening 24, positioned on the wall 16 facing the free end 12 of the body 2 is polygonal, having a plurality of substantially straight sides 25; on the contrary, the radially inner peripheral edge 21. of the rear opening 23, positioned on the bottom wall 15 at the connecting end 11 of the body 2, is preferably substantially round.

The body 2 comprises a plurality of foldable locking lamellar elements 30 (two or more) arranged at the free end

12 of the body 2 and projecting from the front wall 16 into the hollow 10. In the interest of simplicity, hereinafter the locking lamellar elements 30 are referred to as fins.

In particular, the fins 30 axially project into the hollow 10 from the radially inner peripheral edge 22 of the front opening 24, and more specifically, from respective sides 25 of the edge 22 towards the bottom wall 15 and towards the connecting end 11.

The fins 30 are angularly spaced apart from one another along the radially inner peripheral edge 22.

In a first use arrangement of the device corresponding to the lack of fire or the beginning of fire, when temperature is not so high - the fins 30 are substantially flat and parallel to the axis A, that is to say parallel to the outer surface of the corresponding pipe, and substantially perpendicular to the front wall 16. In the shown example, the fins 30 are substantially triangle-shaped, each fin 30 having a footing side 31, joined to the edge 22 (specifically to a side 25 of the edge 22), and two converging sides 32.

Let it be clearly understood that the fins 30 can be otherwise shaped, as a polygon and/ or with bended edges. In fact, in the embodiments shown in figures 4 and 5, the fins 30 are petal-shaped or spearhead-shaped.

Each fin 30 is joined to the front wall 16, and in particular to the radially inner peripheral edge 22 of the body 2, by means of a hinge portion 33 allowing the fin 30 to fold with respect to the front wall 16 and the edge 22 around a rotation axis substantially perpendicular to the axis A.

In the non-limiting shown example, the hinge portion 33 of each fin 30 comprises at least a bridge 34 joining the fin to the front wall 16, and in particular joining the footing side 31 of the fin 30 to the edge 22; the bridge 34 extends through a slot 35 separating the fin 30 from the front wall 16, and in particular, separating the footing side 31 of the fin 30 from the corresponding side 25 of the edge 22.

The hinge portion 33 of each fin 30 may comprise only one bridge 34 arranged, for example, at the center of the footing side 31, or two or more bridges 34 sideways spaced apart from each other. The bridges 34 may have, as well, a smaller thickness with respect to thickness of the fin 30 and/ or front wall 16.

The bridges 34 can be plastically deformed to define plastic hinges. However, the hinge portions 33 can be formed in other ways.

Being substantially parallel to the axis A and facing respective portions of the lateral wall 13, the fins 30 cooperate to delimit the seat 14 and to hold the expandable element 3 in the seat 14.

The expandable intumescent material element 3 is collar-like shaped substantially cylindrical about the axis A, and it is housed in the seat 14, against the lateral wall 13 and between the bottom wall 15 and the front wall 16; the expandable element 3 is sized so as to be fully contained inside the seat 14 and to let the openings 23, 24 free.

In the example shown in the figures, the expandable element 3 comprises two annular adjacent sleeves 36, 37 extending around the axis A and placed side-by-side along the axis A; the sleeves 36, 37 are made of respective different intumescent materials, having a different heat resistance and/ or a different expanding power.

The sleeve number can be generally higher, for example three or four sleeves placed side-by-side according to the activating sequence expected by the manufacturer of the device 1.

In particular, the first sleeve 36, positioned adjacent to the front wall 16, for example in abutment against the free end 12 (that is to say farther from the bottom wall 15) , is made of an intumescent material having a lower heat resistance; the second sleeve 37, positioned at the connecting end 11 (closer to the bottom wall 15), is made of an intumescent material having a better heat resistance .

The first sleeve 36 is made of a first intumescent material having an activating temperature, equal to i , at which it starts expanding. The activating temperature i of the first sleeve 36 is, for example, 100°C.

The second sleeve 37 is made of a second intumescent material having an activating temperature, equal to T₂ , at which it starts expanding, where T₂ > i . For example, the activating temperature T₂ of the second sleeve 37 is, for example, about 270°C.

By way of example only, the first and the second intumescent materials are composed of PVC and graphite mixtures, or else by ABS and graphite mixtures.

Furthermore, according to a preferred embodiment, the support body 2 is made at least partially of a metal material (for example a zinc-plated iron), provided with a powder coating applied by an electrophoresis, for example cataphoresis , painting process. In this way, the device 1 has a high resistance even in aggressive atmospheres (such as corrosive atmospheres or in an environment exposed to saltiness, such as in a naval environment) .

In use, the device 1 is assembled on a pipe, arranged through a wall or floor , in the initial configuration shown in figures 1 and 2 and in the left part of figure 3; the fins 30 are in an initial position where the fins 30 are substantially perpendicular to the front wall 16 and parallel to the axis A and they hold the expandable element 3.

In case of fire, the intumescent materials, and accordingly the whole expandable element 3, expand under the effect of the heat in the hollow 10, filling the whole hollow 10 and pushing the fins 30 towards the front opening 24 and the free end 12; under the effect of the expansion of the expandable element 3 and by virtue of the hinge portions 33, the fins 30 fold passing from an initial position, where the fins 30 leave open the front opening 24, to a closing position, shown in the right portion of figure 3, and where the fins 30 close, at least partially, the front opening 24. In the closing position, the fins 30 are substantially perpendicular to the axis A and placed side-by-side and adjacent to each other and substantially co-planar to each other and to the front wall 16.

The fins 30 are formed so as to make up respective complementary sectors substantially covering the whole front opening 24. In other words, the fins 30 are shaped so that once brought to the closing position, they substantially obstruct the whole front opening 24.

In the embodiment of figure 4, wherein the details same as or like those above described are referred to with the same numerals, the device 1 has fins 30 with a different shape from those illustrated in figures 1-3.

The radially inner edge 22 defining the front opening 24 is substantially circular; the fins 30 are still generally triangle-shaped but with rounded vertices; in particular, each fin 30 has a curved footing side 31 (facing the edge 22) (so as to follow the edge 22); the sides 32 are substantially straight and joined to the footing side 31 through rounded vertices and they converge towards the axis A to form a further rounded vertex; the fins 30 are still joined to the front wall 16, and in particular to the edge 22, through respective hinge portions 33 comprising, in the shown example, a bridge 34 positioned at the footing side 31 center.

In this embodiment too, at the beginning, the fins 30 are in an initial position (not shown) similar to that already described (wherein the fins 30 are substantially perpendicular to the front wall 16 and parallel to the axis A and hold the expandable element 3) . The fins 30 still define respective complementary sectors covering the front opening 24, in the closing position shown in figure 4; however, in this case, the fins 30 only partially close the front opening 24, leaving gaps among the fins 30. These gaps are intended to be filled by the iully expanded intumescent material.

In the further embodiment of figure 5, wherein the details same as or like to those already described are referred to with the same numerals, the device 1 comprises only a pair of diametrically opposed fins 30, located on respective elements 5; the fins 30 can be shaped anyway (for example they can be substantially triangle-shaped with rounded vertices and/ or sides) and project from the edge 22 towards one another. At most, it could be used a single fin 30, properly shaped and sized. Accordingly, the term "plurality of fins" used above and hereinafter, must be understood as extended to the case of the device 1 including a single fin.

Figure 6 shows, in perspective, a section of the device 1, fastened to a wall W and applied to a pipe T made of a polymer or loaded polymer. As would be appreciated, the first sleeve 36 faces the fire side or else the environment where the fire can spread. Therefore the first sleeve 36 heats up before the second sleeve 37, which is positioned between the first sleeve 36 and the wall W.

The annular sleeves 36 and 37 are placed side-by-side and in abutment against each other. However, as an alternative, in between the sleeves an air gap or a third sleeve (not shown) can be provided, made of an intumescent material same as or different from the materials forming the sleeves 36 and 37.

The sleeves 36 and 37 can be regularly ring-shaped made of intumescent material, or they can be formed overlapping a plurality of strips each other, as shown in figure 7 for the sleeve 37, or else they can even be formed coiling an intumescent material band.

The strip configuration is useful to allow the hot air to penetrate between two strips and to deeply heat up the sleeve quicker than in case of a single block of material.

Between the sleeves 36, 37 and the device lateral wall 13 a first interstice 100 is provided, that is to say an air gap referred to as outer air gap. Between the sleeves 36, 37 and the outer surface of the pipe T an interstice 200 is provided, that is to say an air gap referred to as inner air gap.

The operation of the two air gaps 100 and 200 will be explained with reference to figures 7-9, showing corresponding vertical sections of the device 1 in use, in an activating sequence.

In particular, figure 7 shows the device 1 in an idle state, that is to say at rest.

If there is a fire in the room bounded by the wall (to the right of the wall in figures), the air temperature increases and the device 1 undergoes a corresponding heating. The pipe T starts softening and losing its mechanical properties.

On reaching the first activating temperature Ti, the first intumescent material activates and starts expanding.

Figure 8 shows a time immediately after the activation of the first sleeve 36. The first intumescent material expands both in the outer air gap 100, substantially filling it, and towards the inner air gap, without filling it, but in a way such as to bring the fins 30 in abutment against the outer surface of the pipe. The first intumescent material pushes the fins 30 without overcoming them, that is without interposing between the pipe T and the fins 30.

The filling of the outer air gap 100 allows a centripetal force of the second sleeve 37 to be produced. In other words, the first intumescent material expanding in the outer air gap pushes the second sleeve 37 radially towards the pipe T, making it possible to:

- recover any gap between the fins 30 and the pipe T, increased in the intervening period with respect to the configuration shown in figure 7, due to the section reduction of the pipe T occurred because of the corresponding softening, and

- make subsequently the best use of the whole expanding power of the second sleeve 37.

The arrows in figure 8 show the expanding movement of the intumescent materials.

On reaching the second activation temperature T2, also the second sleeve 37 starts expanding. The relative expansion can take place only radially towards the pipe T, because the outer air gap 100 is already fully filled with the expanding material of the first sleeve 36.

The second intumescent material moves in abutment against the pipe T, applying to it a pressure concurring to cause a growing reduction of the free port of the pipe itself, and concurring to push the fins 30 against the pipe T. Since the activation of the second sleeve 37 takes place after the first sleeve has started its expansion, the thrust the second sleeve 37 can apply to the pipe T and to the fins 30 is still the most.

Then, the activation sequence of the sleeves 36, 37 can be determined in advance by the manufacturer, conveniently selecting the sleeves depending on relative geometric, chemical and/ or physics properties.

In practice, the two sleeves 36, 37 act as an actuator pushing the fins 30 into the respective closing position, shown in figure 9, where the whole intumescent material is fully expanded and the pipe has been sealed to prevent the fire from spreading inside it through the wall W. The two sleeves 36, 37 have turned into sealant caps and the fins have taken the configuration shown in figure 4.

Claims

1. Intumescent material fire stop device (1), comprising:

- a support body (2) shaped so as to take a collar-like shape around an axis (A) and to define an opening (24) intended to house a pipe (T) , and

- an expandable element (3), made up of at least one intumescent material, positioned in the support body (2),

- one or more foldable fins (30) joined to the support body (2) by at least one respective hinge portion (33) along a radially inner peripheral edge (22) of said opening (24), and

wherein, due to the expansion of the expandable element (3), the fins (30) are movable between an initial position, in which the fins (30) are substantially parallel to each other and not intercepting said opening (24), to a closing position, in which the fins (30) converge towards the axis (A) to close at least partially said opening (24),

characterized in that said expandable element (3) is made of at least one first intumescent material, expandable at temperatures equal to or greater than a first activation temperature ΊΊ, and at least one second intumescent material, expandable at temperatures equal to or greater than a second activation temperature T2 higher than said first activation temperature ΤΊ, and

in that said first intumescent material and said second intumescent material are shaped as annular sleeves (36, 37) axially staggered with^' respect to said axis (A), and the first intumescent material is positioned at the hinge portions (33) of the foldable fins (30) .

2. Device according to claim 1, wherein said second intumescent material is positioned side-by-side of said first intumescent material with respect to the axis (A) , at the opposite side with respect to said hinge portions (33) and if other intumescent materials define the expandable element (3) they are positioned adjacent to each other, in succession.

3. Device according to claim 1 or claim 2, wherein the support body (2) comprises an annular seat (14) to accommodate said expandable element (3),

wherein said seat (14) extends in a radial direction between the fins (30) and a lateral wall (13) of the support body (2) and in an axial direction between a bottom wall (15) and a front wall (16) that are opposed and facing to each other and substantially perpendicular to the lateral wall (13), and

wherein the expandable element (3) is positioned in abutment against the fins (30), and

wherein the expandable element (3) and^" said lateral wall (13) define therebetween a first interstice, or outer air gap (100), having the function of promoting the initial expansion of the first intumescent material such that during the expansion it is inserted at least partially between the second intumescent material and said lateral wall (13) and it pushes said second intumescent material towards the fins (30).

4. Device according to any one of claims 1-3, wherein between the fins (30) and the opening (24), namely between the fins (30) and the pipe (T) able to be housed in said opening (24), a second interstice or inner air gap (200) are defined having the function of aiding the initial expansion of the second intumescent material such that the moment applied to the hinge portions (33) can be maximized and aiding the closing of the fins (30).

5. Device according to any one of claims 1-4, wherein the support body (2) comprises a plurality of foldable fins (30) arranged around the opening (24) and angularly spaced apart from one another along said radially inner peripheral edge ( 22 ) .

6. Device according to any one of the preceding claims, wherein the hinge portion (33) is shaped so as to allow the fin (30) to fold with respect to the front wall (16) around a rotation axis substantially perpendicular to the axis (A) .

7. Device according to any one of the preceding claims, wherein in the respective initial position the fins (30) project axially, overhanging, from the radially inner peripheral edge (22) of the front opening (24) .

8 . Device according to any one of the preceding claims., wherein each fin (30) is substantially triangle-shaped, or spearhead-shaped, optionally with curved vertices and/or sides .

9. Device according to any one of the preceding claims, wherein the hinge portion (33) comprises at least one bridge (34) joining the corresponding- fin (30) to a front wall (16) of the support body (2) and extending through a slot (35) that separates the fin (30) from the front wall (16) .

10 . Device according to claim 9, wherein the bridge (34) is plastically deformable to define a plastic hinge.

11. Device according to any one of the preceding claims 1-10, wherein a first sleeve (36), made of said first intumescent material, has lower heat resistance and/or lower expanding power than a second sleeve (37) made of said second intumescent material.

12. Device according to any one of the preceding claims, wherein the support body (2) is made at least partially of a metal material, for example a zinc-plated iron, provided with a powder coating applied by an electrophoresis, for example cataphoresis , painting process .

13. Device according to any one of the preceding claims, wherein at least one of said annular sleeves (36, 37) is formed by coiling a band of the corresponding intumescent material, or is made of strips of the corresponding intumescent material, that are wound overlapping each other.

14. Assembly comprising a pipe (T) and a device according to any one of the preceding claims 1-13, wherein the pipe (T) is inserted in said opening (24), coaxially to the device with respect to the axis (A) , and between the outer surface of the pipe (T) and the fins (30), an inner air gap (200) is radially defined in which the fins (30) are free to move by means of the expansion of the expandable material (3), before abutting against the outer surface of the pipe (T) .■

15. Assembly according to claim 14, wherein the pipe (T) is made of a plastic material, even with large thickness .

16. Use of the device according to any one of claims 1- 13, or of the assembly according to any one of claims 14-15 for implementing safety measures for conduits in civil, industrial, naval fields.

17 . Method for restricting or preventing the fire spread through a pipe (T) made of a plastic material, comprising the subsequent steps of:

- placing a fire stop device (1) according to any one of claims 1-13 around the pipe (T) , leaving an air gap (200) between the outer surface of the pipe (T) and the fins (30), and fastening the device to a wall or to a floor (W) , with the first intumescent material (36) facing the opposite side of the wall or floor;

- allowing, at the beginning, the first intumescent material to expand at least partially around the second, not expanded, intumescent material, and- towards the fins (30), following the inner air gap (200), pushing the fins to abut against the pipe (T) , the latter being in case subjected to softening, when the air in the environment in which the device (1) is located reaches the first temperature ΊΊ;

- allowing the second intumescent material to expand in order to apply, along with the first intumescent material, a thrust onto the fins (30) up to move them to the closing position, when the environment air reaches, the second temperature T2;

- completing the expansion of the expandable element (3) for sealing the pipe (T) or what is left of it.