SE543236C2 - A silencer for airflow in ventilation - Google Patents

Abstract

The present invention relates to a silencer (10) for airflow (7) in ventilation, comprising an outer air-proof casing (2), which outer air-proof casing comprises an air inlet (3) at a first end (2A) and an air outlet (4) at a second end (2B), an inner through channel (5) in fluid communication with the air inlet and air outlet, and an air-permeable sound-reducing material (6) in an inner space of the outer air-proof casing between the inner through channel and the air-proof outer casing, the inner air-permeable sound-reducing material being thermal insulating and non-combustible.

Description

ëßylencer for ašrflow in ventilation TECHNICAL FIELD The present invention relates to a silencer for ventilation ducts, comprising an outer casing, aninlet, an outlet, an inner channel for letting ventilation air through the silencer, and a sound-attenuation material arranged in a space between the inner channel and the outer casing. The outer casing of the silencer is made of non-combustible material.

BACKGROUND ART There are a lot of known silencers for reducing unwanted noise in ventilation systemsemanating from air flowing through ventilation ducts and other components of the system.

One example of such a silencer is disclosed in EP 1 998 119 B1.

Some known silencers reduce the unwanted noise while fulfilling fire proof criteria in that theouter casing of the silencer is made of metal and the sound-attenuation material arranged inthe silencer are made of non-combustible material, such as mineral wool, e.g. stone or glass wool. Glass wool melts at about 400 to 500°C, and stone wool melts at about 1000 to 1500 °C.

Prior art silencers suffer from at least some disadvantages, e.g. decompose or break up too fast when exposed to excessive fire or heat.

SUMMARY OF THE INVENTION lt is, accordingly, an object of the present invention to overcome deficiencies of the prior art, such as indicated above.

Another object of the present invention is to increase the time during which the silencer is kept structurally intact when exposed to excessive fire and/or heat.

An additional object of the present invention is to slow down the spread of heat and fire pastor via the silencer by keeping the silencer structurally intact during a longer period of timewhile decreasing the rate of heat and fire propagation when exposed to excessive fire/heat making the silencer into a passively working firebreak.

Yet another object of the present invention is to increase the time during which the silencer is kept structurally intact when exposed to excessive fire/heat by making it in a material being 2fire proof and non-combustible and less prone to conduct heat from an external ventilation component, e.g. a ventilation duct or connector, to the outer casing of the silencer.

One other object of the present invention is to prolong the structural integrity ofthe silencerwhen exposed to excessive fire/heat by using a material that increase the resistance againstexcessive heat by being able to emit water and water vapour when the temperature exceedsabout 500°C to further prolong the heat resistance ofthe silencer. For this, gypsum being ableto give off chemically bound water at above about 500°C is used, which further emission ofwater aids in cooling ofthe silencer. Examples of suitable gypsum has a thickness of about atleast 10 to 15 mm and a heat or thermal resistance Rp of about at least 0.07 m2°C/W, and acoefficient of linear expansion of about 25x10'6 °C'1. Suitable gypsum boards/plates have a fire resistance grade according to DIN 4102 and DIN EN 13501 of at least A2-s1, d0.

Still another object ofthe present invention is to decrease the rate of heat conduction so thatthe silencer is kept structurally intact for a prolonged period of time when exposed toexcessive fire/heat by using a fire proof and non-combustible material having a lower capacity of heat transmission than materials hitherto used in the outer casing of the silencer.

An additional object of the present invention is to make at least the gables of the outer casingofthe silencer to which any external ventilation component is mounted in a fire proof andnon-combustible material being less prone to conduct heat from the external ventilationcomponent, e.g. a ventilation duct, to the outer casing or vice versa, while keeping the silencer structurally intact for an increased period of time when exposed to excessive fire and/or heat.

The objects are achieved by means of a silencer for ventilation, as claimed in the associated in- dependent claim, preferred variants thereof being defined in associated dependent claims.

At least one of above and further objects are achieved by means of a silencer in ventilation,comprising an outer air-proof casing, which outer air-proof casing comprises an air inlet at afirst end and an air outlet at a second end, an inner through channel in fluid communicationwith the air inlet and air outlet, and an air-permeable sound-reducing material in an innerspace of the outer air-proof casing between the inner through channel and the air-proof outer casing, the air-permeable sound-reducing material Es fšbrous also--šaeir-rg-theeflafsfæal-heat insulating and non-combustible, _: ' wherein the first and second casing ends of the silencer each comprises a fire and air~proof gable made at least partly of heabiëhemml 3insulating material, and to which heat insulating material of the fire and air-proof gable the air inlet and air outlet, respectively, is connected! and each fire ared ainproof ”able cornprises av: internaâ šwišovv connector and an externaš hfßliovv connector as defined än the characterisâng portion ofthe independent cåašm.

Further objects and features of the present invention will appear from the following definitions of aspects/examples of the invention.

According to an aspect, the silencer according to any of the former and/or latter aspects,wherein each fire arifi ašnproof gable comprises a first hole forming part ofthe air inlet or airoutlet. According to another aspect, in the silencer according to any of the above and/orbelow aspects the first hole is made through the heatfïëhelfleaqaš insulating material ofthe fire and ašr~proof gable. ln one aspect, in the silencer according to any ofthe above and/orbelow aspects the first hole is configured for alignment with the inner through channel of theouter air-proof casing. ln another aspect, in the silencer according to any of the above and/orbelow aspects, the first hole of the air inlet of the outer air-proof casing is configured foralignment with the first hole of the air outlet of the outer air-proof casing. According to afurther aspect, in the silencer according to any preceding and/or subsequent aspect, the airinlet and outlet of the outer air-proof casing comprises an inner hollow connector with a firstend adapted for air-tight connection to the inner through channel and an outer hollowconnector with a first end adapted for air-tight connection to at least one external ventilationcomponent. According to a still further aspect, in the silencer according to any of the aboveand/or below aspects, each connector is a flanged coupling. According to yet an aspect, in thesilencer according to any preceding and/or subsequent aspect, each connector is connectedwith a second end to the heabiëhemml insulating material ofthe fire and aâr~proofgable such that a heatfïtflaeenaëil insulation and thermal break zone is formed between eachconnector and the outer air-proof casing. According to another aspect, in the silenceraccording to any preceding and/or subsequent aspect, the heat insulatingmaterial of the fire_a_gç_çâ__ai_r¿-_proof gable is made in the form of a plate. According to one moreaspect, in the silencer according to any preceding and/or subsequent aspect, the fire__ge_z_f_1_g:_i___.ï_e_i__rj_-¿proof gable is configured as a sandwich structure of or comprising at least two plates made ofdifferent materials ofwhich at least one or a first plate is made ofthe heatfïthern-"ea-š- insulating material. According to an additional aspect, in the silencer according to 4 any of the above and/or below aspects, each fire and air-proof gable comprises a second holebeing larger than the first hole of the fire and ašr~proof gable. According to one aspect, in thesilencer according to any preceding and/or subsequent aspect, the second hole is adapted tobe in alignment with the first hole of the fire__a_n_d__a_igj_-_proof gable. According to one furtheraspect, in the silencer according to any of the above and/or below aspects, each fire__a__r_1_d__a_i_ej_-¿yproof gable comprises at least another plate and a second hole in this other plate, which otherplate is configured to be an outer part ofthe outer air-proof casing and the second hole is athrough hole adapted in size to at least partly expose the first plate ofthe heatftheefa-"sfæaliinsulating material. According to still an additional aspect, in the silencer accordingto any preceding and/or subsequent aspect, each second connector end is adapted to beconnected to the exposed zone or area or surface ofthe first plate of the »flesistant-irtsailatärig material of the fire and ašr~proof gable without being in physical contactwith the outer air-proof casing. According to yet a further aspect, in the silencer according toany preceding aspect, the _šj__ç_.ï_e_t__j_n_s_u_lafçi_n_g material has a thermal insulationcapacity of at least about 0.07 m2°C/W or between at least about 0.05 m2°C/W to 0.2 m2°C/Wor between at least about 0.07 m2°C/W to 0.15 m2°C/W. According to one aspect, the silenceraccording to any preceding aspect comprises an inner channel made up by a soundattenuating material in the form of two elongated shaped or moulded halves, which halveswhen put together form an enclosed hole extending along their whole lengths similar to abuilding block with a through channel. ln another aspect, the silencer comprises an innerchannel made of a separate perforated and elongated cylindrical tube, preferably of metal,which tube is enclosed by a sound reducing material put around the inner tube between it andthe outer casing in the inner space of the silencer. ln one other aspect, the silencer comprisesthe inner channel made ofthe separate perforated tube being covered over its envelopesurface, i.e. between its outside and the sound reducing material, with an air/sound permeable material in the form of a web/cloth.

Further objects and features of the present invention will appear from the following detailed description of aspects/examples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be explained in further details with reference to the drawings showing aspects thereof. 5Figure 1A is a perspective view of a square-shaped configuration of one embodiment of a silencer according to the invention.

Figure 1B is a perspective view of a rounded configuration of another embodiment of a silencer according to the invention.

Figure 2 is an exploded diagram in perspective of an embodiment ofthe silencer in Fig. 1A before/during assembly or after/during disassembly.

Figure 3 is a sectional view ofthe silencer in Figs. 1A or 1B before disassembly or after assembly taken along the full length of the silencer.

Figure 4 is a front or back view ofthe silencer in Figs.1A, 2, and 3 as seen from outside the silencer and towards an inlet or outlet of the silencer with fastener heads exposed.

Figure 5 is an exploded diagram in perspective of another embodiment ofthe silencer in Fig. 1A before/during assembly or after/during disassembly.

Figure 6 is a sectional view ofthe silencer in Figs. 1A or 1B before disassembly or after assembly taken along the full length of the silencer.

Figure 7 is a front or back view ofthe silencer in Figs.1A, 2, 3, 4, and 5 as seen from the inside of the silencer and towards an inlet or outlet of the silencer with fasteners fully exposed.

Figure 8 is a front or back view ofthe silencer in Figs. 4 and 7 as seen from outside the silencer and towards an inlet or outlet of the silencer with other fastener heads exposed.

Figure 9 is an exploded diagram in perspective view ofthe silencer in Figs. 4, 7, and 8 before/during assembly or after/during disassembly.

DETAILED DESCRIPTION The invention relates to a silencer 10 for connection to one or more external ventilationcomponents, such as ventilation ducts 1, to reduce noise due to air flow, fans, valves and soon. The silencer 10 is shown in figs. 1A to 9 in at least two different configurations and/orembodiments. The silencer 10 comprises an outer airproof casing 2 with two ends, a first end2A and a second end 2B. The outer airproof casing 2 ofthe silencer 10 is formed to create aninner space 2C of the silencer 10. The silencer 10 comprises at least one air inlet 3 at its firstend 2A and at least one air outlet 4 at its second end 2B. The silencer 10 also comprises a continuous, inner channel 5 for letting through air 7 from its inlet 3 to its outlet 4. The inner 6 channel 5 is situated inside the outer casing 2 and its inner space 2C. The silencer 10comprises an air permeable material 6 in its inner space 2C between outer casing 2 and innerchannel 5. This air permeable material 6 works as a sound-attenuation material and isarranged in the inner space 2C between inner channel 5 and outer casing 2. Silencer 10 isadapted to be part of a ventilation system comprising fans, valves, connectors, ventilationducts, heating and/or cooling batteries, and, such systems are common general knowledgeand well-known by the skilled person, hence, any components for making such a ventilation system as a whole for ventilation air flow 7 is not necessary to explain in detail herein.

The silencer 10 shown in figs. 1A to 9 basically comprises three components, the outer air-proof casing 2 made of sheet metal tube (square-shaped in figs. 1A, 2, 4, 5, and 7 to 9, androunded in figs. 1B, 3, and 6), the inner channel 5 coaxial with the outer tubular casing 2, andthe sound-attenuation material 6 filling the inner space 2C between outer casing 2 and innerchannel 5. The air-permeable sound reducing material 6 is fibrous and allows air flow 7 to passthrough the inner channel 5 ofthe silencer and is able, at the same time, to prevent looseparts of the sound-attenuation material from being carried into the inner channel and further out of the outlet 4 into the ventilation duct 1 and further into the ventilation system. ln figs. 1A and 1B, the outer silencer casing 2 comprises a gable 20 at each of its ends 2A and2B. Each gable 20 is a front or end plate defining the length ofthe silencer 10 excluding thelength of any protruding connecting part of the inlet 3 or outlet 4. Each gable 20 is attached byfasteners 30 to the silencer 10 at an associated end 2A and 2B to enclose the inner space 2Caxially from those ends (see figs. 2, 4, 5, and 7). Each gable 20 comprises an internal hollowconnector 23 (not shown in figs. 1A, 1B, but in figs. 2 to 9) adapted to fit into and be in fluidconnection with the inner channel 5 and an external hollow connector 24 adapted to fit to and be in fluid connection with an external ventilation component, e.g. a ventilation duct 1.

Each gable 20 with its internal 23 and external connector 24 has an aligned centre hole oropening 21 that extends all the way through the gable and its connectors to define/form atleast a part of the inlet 3 and outlet 4 of the silencer 10, see figs. 3, 6, 8 and 9. The externalconnector 24 is a connecting piece, which have protruding parts 24A extending outside thesilencer 10 for coupling to ventilation pipes 1 in a ventilation system of which the silencerforms part. The internal connector 23 is a connecting piece, which have protruding parts 23A configured to extend in the opposite direction of the external connector 24 into the inner 7 channel 5 of the silencer 1 for coupling thereto. The external 24 and internal connector 23 arearranged opposite each other. The connectors 23 and 24 are facing/extending or protruding inopposite directions from their associated gable 20 when assembled thereon. The external 24and internal connector 23 are arranged opposite each other at different sides of each gable20. Each of the gables 20 is connected with its internal connector 23 inserted into oppositesilencer ends 2A, 2B and fastened by fasteners 30 to the ends of the outer casing 2. Each ofthe protruding parts 24A of the external connector 24 forms an exposed outer end defining apart of an associated free end ofthe silencer 10, i.e. the openings of its inlet 3 and outlet 4before the silencer is assembled into a ventilation duct 1 or the like, i.e. when the silencer isfreestanding. Each connector 23, 24 has another end 23B and 24B adapted to be attached toopposite sides of a common gable 20. The external connector 24 has its other end 24Battached by fasteners 31 to one side of the gable 20, i.e. an external gable side facing out-wards, while the internal connector 23 has its other end 23B attached by the same fasteners31 as the external connector 24 or other fasteners to another side of the gable 20, i.e. aninternal and opposite gable side facing inwards when the silencer 10 is assembled (see its disassembled state in figs. 2 and 5 and its assembled state in figs. 1A, 1B, 3, and 6).

Each gable 20 is made up of at least two separate plates 22, 25 (see fig. 8 and 9), each platebeing made of fireproof and non-combustible material. One plate 22 is made of gypsum andforms the most important fire protection of each gable 20 and thereby the silencer 10. Theother plate 25 is made at least partly of metal and forms a stabilising part of the gable 20. Thegypsum plate 22 is thicker than the other plate 25. Gypsum plate 22 and the other plate 25 aremade to be sandwiched together and to snugly fit into an associated end 2A or 2B of the outercasing 2 enabling them to be inserted therein and fastened by the fasteners 30 (see figs. 2 to7) extending from the outside ofthe casing and through the casing into the gypsum plate 22and the other plate 25. The improved fire protection of the silencer 10 is accomplished bymaking a centre hole 21A through the gypsum plate 22 that is smaller than a correspondingand aligned hole 21B in the other plate, i.e. the metal plate 25 (see figs. 4, 7, 8, and 9), butwhich smaller hole 21A of the gypsum plate 22 and larger hole of the metal plate 25 correlatewith the openings 21 through the connectors 23 and 24. Size, shape and alignment of thesmall holes 21A at each end 2A, 2B of the silencer 10 are adapted so that they optimise the air flow 7. Size, shape and alignment ofthe big holes 21B at each end 2A, 2B ofthe silencer 10 are 8 adapted so that they do not make the metal plate 25 touch, i.e. come into physical contactwith any of the connectors 23, 24, in particular the external connector 24 when the externalconnector is attached to the gypsum plate 22 and the metal plate 25 is attached to gypsumplate 22 (see fig. 8). Gypsum plate 22 forms a base or underlay for the connectors 23 and 24 tobe attached to at opposite sides of the gable 20 with the thereby commonly formed andaligned through holes or openings 21 and 21A, and the large holes 21B, after assembly. Thelarger hole 21B of the metal plate 25 is partly covered by the gypsum plate 22 when the twoplates are assembled together (see figs. 4, 7, and 8). The internal connector 23 could be anintegrated part of or be integrated in the gypsum plate 22. ln fig. 8, the large hole 21B in plate25 is indicated as a not perfectly circular hole, i.e. it has a somewhat elliptic shape but could ofcourse be circular. ln fig. 8, the small hole 21A in gypsum plate 22 is indicated by one largercircle in broken line and one smaller circle in solid line. The size ofthe small hole 21A couldcorrelate perfectly to the opening 21 ofthe air inlet 3 and air outlet 4, and its shape could benon-circular as the larger hole 21B, but is preferably circular. The second hole 21B has its centre axis in alignment with the centre axis ofthe first hole 21A of the fireproof gable 20.

The air-permeable sound-attenuation material 6 inside the silencer 10 is heat/thermalinsulating/resistant and non-combustible/fireproof and this is combination with the first andsecond casing ends 2A, 2B each made up of a fireproof gable 20 made at least partly ofheat/thermal insulating/resistant material 22, i.e. gypsum with high thermal insulance orinsulation capacity, see the summary and also being non-combustible/fireproof makes thesilencer 10 according to the invention able to fulfil at least the fire proof criteria of E|30 andE60, and with a protective distance of 10 mm at least El 60. This is specifically achieved in thatthe first hole 21A is made through the heat/thermal insulating/resistant material 22 of thefireproof gable 20. ln some aspects, the first hole 21, 21A is configured for alignment with theinner through channel 5 ofthe outer air-proof casing 2 and/or the first hole 21, 21A ofthe airinlet 3 is configured for alignment with the first hole 21, 21A ofthe air outlet 4. As the air inlet3 and air outlet 4 each comprises the inner hollow connector 23 with its first end 23A beingentities adapted for air-tight connection to the inner through channel 5. The same goes for theouter hollow connector 24 with its first end 24A being adapted for air-tight connection to at least one external ventilation component 1. 9 ln an aspect, each connector 23, 24 is a flanged coupling to achieve a more stable end-to-endconnection to the gypsum plate 22 as an underlay. As each connector 23, 24 is connected withits second end 23B, 24B to the heat insulating gypsum material 22 of the fireproof gable 20 aheat/thermal insulation and thermal/break zone and/or area and/or volume and/or surface isformed between each connector and the outer air-proof casing 2. ln other words, the fire-proof gable 20 is at least partly or wholly configured as a sandwich structure comprising the atleast two plates 22, 25 made of different materials, i.e. at least gypsum and/or metal, of whichat least the first plate 22 is made of heat/thermal insulating/resistant gypsum material. Eachfireproof gable 20 comprises the second hole 21B (in metal plate 25) being larger than the firsthole 21A of the fireproof gable, i.e. in the gypsum plate 22. The second hole 21B is adapted to be in alignment with the first hole 21A ofthe fireproof gypsum plate 22. ln one aspect, the hole 21B in the metal plate 25 is a through hole adapted in size to at leastpartly expose the first gypsum plate 22 after assembly together. The improved fire protectionof the silencer 10 is accomplished in that each second connector end 23B, 24B is adapted tobe connected to the exposed zone or area or surface of the first gypsum plate 22 withoutbeing in physical contact with the outer air-proof casing 2 and/or the metal plate 25. Thefasteners 30 and 31 are arranged so that no physical contact between outer air-proof casing 2and the metal plate 25 and the connectors 23, 24 and/or the fasteners themselves occurs to further hindering/slowing down heat and fire propagation via/in the silencer 10.

The gypsum material 22 has a thermal insulation capacity corresponding to a heat or thermalresistance Rp of about at least 0.07 m2°C/W; preferably between at least about 0.05 m2°C/Wto 0.2 m2°C/W; more preferred between at least about 0.07 m2°C/W to 0.18 m2°C/W, and most preferred between at least about 0.07 m2°C/W to 0.15 m2°C/W or about 0.07 m2°C/W. ln figs. 2 and 3, the inner channel 5 is made up by surrounding it with the sound attenuatingmaterial 6 in the form of two elongated halves, an upper half 6' and a lower half 6”. Each half6' and 6" has a U- or cup-shaped cross-section and are adapted to be put together with thelegs of their Uzs abutting against each other, whereby a through hole in the form ofthe innerchannel 5 is formed there through, i.e. the inner channel 5 is formed by the inner surface ofthe opening through the halves 6' and 6" .The two halves 6' and 6" are formed into twosubstantially shape stable entities or pieces of sound reducing material, preferably stone wool for fire/heat resistance, e.g. by moulding. A first end 6A and a second end 6B of the halves 6' and 6” and the halves themselves (figs. 2 and 3) are formed to make the inner channel 5 andits first and second end to fit securely and snugly with one internal connector 23 (i.e. a firstgable 20) at the first end 6A and to fit securely and snugly with a second internal connector 23 (i.e. a second gable 20) at the second end 6B inside the silencer 10. ln figs. 5 and 6, the inner channel 5 is made of a separate perforated and elongated cylindricaltube, preferably of metal, which tube 5 is wrapped or enclosed or surrounded with the soundreducing material 6, e.g. in the form of loose stone wool or mats put around the inner tube 5between it and the outer casing 2 in the inner space 2C. After assembly of the silencer 10 athrough hole in the form ofthe inner channel tube 5 is formed there through. A first end 5Aand a second end 5B ofthe inner tube channel 5 (figs. 5 and 6) are adapted to fit securely andsnugly with one internal connector 23 (= a first gable 20) at the first end 5A and to fit securelyand snugly with a second internal connector 23 (= a second gable 20) at the second end 5Binside the silencer. The tubular inner channel 5 in figs. 5 and 6 is made to prevent loose partsof the sound-reducing material 6 from being carried into it through its perforation and to theoutlet 4 out into the ventilation duct 1 and further into the ventilation system. The preventionof parts of the sound attenuating material 6 coming loose and being transported furtherdownstream of the silencer 10 is in one aspect improved by covering the external/envelopesurface ofthe inner tube channel 5, i.e. between its outside and the sound reducing material6, with some kind of air/sound permeable material 8, such as a porous fabric or cloth 8 or thelike, to make the inner channel 5 less prone to let through any sound reducing material 6 viaits perforations from the inner space 2C and further into and downstream in the ventilationsystem. This fabric or cloth 8 is preferably a non-woven synthetic material 8, such as Polyester,e.g. POLDUK, working as an additional filter 8 besides the more coarse perforations oftheinner channel 5. This additional filter 8 is a screen cloth or filtration fabric with smaller meshthan the perforated inner channel 5. Each pore or opening ofthe filter 8 is smaller in size thaneach perforation of the inner channel 5. The filter 8 has more openings per surface unit/areacompared to the inner channel 5. The filter 8 lets through air and thereby sound to ”help” the silencer 10 while not letting through any loose parts of the sound attenuation material 6.

Each fireproof gable 20 is made at least partly of fireproof material and adapted to function asa thermal barrier/firebreak between the in-/outlets 3, 4 of air and the outer air-proof casing 2.

Each hole 21, 21A, 21B of each gable 20 enables air 7 to be let in or out ofthe silencer 10 as it 11 is made through the fireproof material of each fireproof gable 20, which fireproof material ismade in the form ofthe plates 22 and 25. Each connector 23, 24 of the gable 20 forms at leasta part of the air inlet 3 or air outlet 4 of the silencer 10. Each connector 23, 24 is connectedwith its second end 23B, 24B to the heat insulating and thermal resistant gypsum gablematerial 22 in such a way that a heat insulation and firebreak zone/area/volume/surface isformed between each connector and the outer air-proof casing 2. Each connector 23, 24 isconnected with its second end 23B, 24B by fasteners 31 to the thermal resistant gypsum plate22 such that each connector is physically and thermally separated from each other and theouter air-proof casing 2, i.e. the gypsum plate 22 forms a firebreak and distance between theconnectors 23, 24 and between the connectors and the outer casing 2. Each connector 23, 24is connected with its second end 23B, 24B to the thermal resistant gypsum gable plate 22 insuch a way that a distance is created both in the longitudinal direction and the radial, i.e.sideways and in the width and breadth direction ofthe silencer 10 between the connectorsand the outer air-proof casing 2 increasing/prolonging the thermal resistivity of each fireproof gable 20 and thereby the silencer 10. ln fig. 9, the gable 20 is shown with the gypsum plate 22 and metal plate 25 being squareshaped in their planes of extension, however, the gypsum plate 22 and the metal plate 25could of course be formed with rounded shapes, e.g. extend in planes of extension beingcircular or elliptic as understood when viewing the gables 20 shown in fig. 1B and all the other cylindrically shaped parts ofthe silencer, such as the outer casing 2 and its inner space 2C.

Claims (13)

12

1. CLAll\/IS

2. A silencer (10) for airflow (7) in ventilation, comprising an outer air-proof casing (2),which outer air-proof casing comprises an air inlet (3) at a first end (2A) and an air outlet(4) at a second end (2B), an inner through channel (5) in fluid communication with theair inlet (3) and air outlet (4), and an air-permeable sound-reducing material (6) in aninner space (2C) of the outer air-proof casing between the inner through channel (5) andthe air-proof outer casing, the air-permeable sound-reducing material (6) is fibrous, heatinsulating and non-combustible, wherein the first and second casing ends (2A, 2B) ofthesilencer (10) each comprises a fire and air-proof gable (20) made at least partly of heatinsulating material (22), and to which heat insulating material ofthe fire and air-proofgable the air inlet (3) and air outlet (4), respectively, is connected, c h a r a c t e r i z e d inthat each fire and air-proof gable (20) comprises an internal hollow connector (23)adapted to fit into and be in fluid connection with the inner through channel (5) and anexternal hollow connector (24) adapted to fit to and be in fluid connection with anexternal ventilation component (1), that the external connector (24) is a connecting piece, which comprises a firstend (24A) extending outside the silencer (10) for coupling to the external ventilationcomponent (1) and the internal connector (23) is a connecting piece, which comprises afirst end (23A) configured to extend in the opposite direction of the external connectorinto the inner channel (5) of the silencer (10) for coupling thereto, and that each connector (23, 24) has another end (23B, 24B) adapted to be attachedto opposite sides of the common fire and air-proof gable (20) and the heat insulatingmaterial (22) of the fire and air-proof gable such that a heat insulation and thermal break zone is formed between each connector and the outer air-proof casing (2).

3. A silencer (10) according to claim 1, wherein each fire and air-proof gable (20) comprises a first hole (21, 21A, 21B) forming part ofthe air inlet (3) or air outlet (4).

4. A silencer (10) according to claim 2, wherein the first hole (21, 21A) is made through the heat insulating material (22) ofthe fire and air-proof gable (20).

5. A silencer (10) according to claim 2 or 3, wherein the first hole (21, 21A, 21B) is configured for alignment with the inner through channel (5) of outer air-proof casing (2).

6.5

7.

8.

9.

10.

11.

12.

13. 13A silencer (10) according to claim 2, 3 or 4, wherein the first hole (21, 21A, 21B) ofthe airinlet (3) of the outer air-proof casing (2) is configured for alignment with the first hole (21, 21A, 21B) of the air outlet (4) of the outer air-proof casing. A silencer (10) according to claim 1, wherein each connector (23, 24) is a flanged coupling. A silencer (10) according to any preceding claim, wherein the heat insulating material (22) of the fire and air-proof gable (20) is made in the form of a plate. A silencer (10) according to any preceding claim, wherein the fire and air-proof gable(20) is configured as a sandwich structure of at least two plates (22, 25) made ofdifferent materials ofwhich at least one first plate is made ofthe heat insulating material (22). A silencer (10) according to claim 8 when claim 7 is dependent on any of claims 2 to 5,wherein each fire and air-proof gable (20) comprises another plate (25) with a secondhole (21B) being larger than the first hole (21A) in the first plate (22) of the fire and air-proof gable. A silencer (10) according to claim 9, wherein the second hole (21B) is adapted to be in alignment with the first hole (21A) of the fire and air-proof gable (20). A silencer (10) according to any of claims 8 to 10 when claim 8 is dependent on any ofclaims 2 to 7, wherein each fire and air-proof gable (20) comprises at least another plate(25) and a second hole (21B) in this other plate, which other plate is configured to be anouter part of the outer air-proof casing (2) and the second hole is a through holeadapted in size to at least partly expose the first plate (22) of the heat insulating material. A silencer (10) according to claim 11 when any of claims 7 to 11 is dependent on claim 1,wherein each second connector end (23B, 24B) is adapted to be connected to theexposed zone of the first plate (22) ofthe heat insulating vifiateriai ofthe fire and air- proof gable (20) without being in physical contact with the outer air-proof casing (2). A silencer (10) according to any preceding claim, wherein the heat insulating material (22) has a thermal insulation capacity of at least about 0.07 m2°C/W or between at least 14about 0.05 m2°C/W to 0.2 m2°C/W or between at least about 0.07 m2°C/W to 0.15m2°C/W.