GB1583995A

GB1583995A - Ventilators

Info

Publication number: GB1583995A
Application number: GB22713/77A
Authority: GB
Original assignee: Colt International Ltd
Current assignee: Colt International Ltd
Priority date: 1976-06-05
Filing date: 1977-05-30
Publication date: 1981-02-04
Also published as: AU508734B2; CH615264A5; ATA395677A; LU77481A1; NL7706113A; FR2353808A1; NZ184270A; AU2569777A

Abstract

In the cabinet (2) of the ventilation device are four ducts (3a to 3d) for the passage of the air expelled from the interior of the building through an opening (1) in a roof. These ducts (3a to 3d) are defined laterally by mutually parallel longitudinal walls (4) which are formed by the angled parts having the general shape of a V. The apexes (13) of these walls (4) are approximately at mid-height between the air admission openings (7) and the air outlet openings (8) of the ducts (3a to 3d). Protection against atmospheric precipitation (21) is ensured by the fact that the admission openings (7) are covered by panels (15, 16) of the walls (4). Rainwater is collected in gutters (19). Sound insulation is provided by the deflecting and reflecting of the sound waves (20). <IMAGE>

Description

(54) IMPROVEMENTS IN OR RELATING TO VENTILATORS (71) We, COLT INTERNATIONAL LIMI TED, a British Company of New Lane, Havant, Hampshire, -P09 2LY, - do whereby declare the invention, for which we Ipray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and 'by the following statement: The invention comprises improvements in or relating to ventilators and concerns a proof -ventilator 'mounted on a buliding over :a horizontal or slightly inclined roof aperture.

The task underlying the invention is to provide a a ventilator of this kind, more es- pecially for industrial buildings, which, while having a space saving, flat and simple design, provides a good sound insulation, - a ilow fall back of . dust particles, and a reliable protection against the - weather to gether with good ventilation efficiency.

According to the invention there is provided a roof ventilator mounted on a building over a horizontal or slightly in clined roof 'aperture, the ventilator comprising an open topped and open bottomed housing having two opposite pairs of side walls, a downwardly directed air inlet aper ture at its lower end, opening to said roof aperture, and an upwardly directed -air outlet aperture at its - upper end, - opening directly to the outside of the building, there being a plurality of upwardly extending air ducts defined in the housing for the passage of exhaust air, each duct comprising an air inlet aperture at its lower end, opening to said housing air inlet aperture, and an outlet aperture gt its opposite, upper end, opening to said - housing air outlet aperture, each ~ duct being defined ' between two opposite pairs '-6f side wails one pair of which are vertically disposed and the other pair of which comprise inclined upper and lower sections disposed in corresponding V-forma tion, the vertices of said other opposite pair of side walls being staggered - with respect to the lower and upper edges of those walls by an amount not less than the width of the duct dir inlet aperture and the duct air outlet aperture respectively, measured in the direction of said stagger, and for each duct, a gutter positioned to capture precipitations draining down the upwardly facing surface of the lower section of said other - opposite pair of walls defining the duct which is exposed internally (of Xthe duct, said gutters leading outside said housing.

,The V-form walls provide a flow path with a deflection for the air flow through each duct. This air flow deflection does -not materially hinder the air passage through the duct. so that a ventilator according to the invention :works at a good ventilating efficiency. Simultaneously, very small dust separation is experienced in the ducts because of the substantially laminar -'flow of .air and the prevention of air vortices in the ducts. Thus, dust particles are carried up- wardly through the ventilator and out'of the building instead of falling back into the building or being trapped in the ventilator, thus reducing its maintenance requirements.

The V-form walls allow a 'flat, space-saving design of ventilator and provide a good sound insulation by deflection and reflection of sound waves. In addition, a reliable weather protection is ensured due to the - staggering of the vertices df the V-form walls. A highly effective roof ventilator is thus provided, which can be used over roof openings in a roof ridge or at any desired point on a flat-roof or a roof having a slight -inclination. The ventilator of the invention is simple and achieves ventilation with a considerable - reduction of noise'level outside the building and a simultaneous weather protection inside the building.

the inclined sections of said other op posite pair of the duct side walls may advan tageously be disposed at right angles to one another, which allows a simple production of the ventilator for a particularly good sound insulating effect, particularly if the sections -!are formed by by individual plates which are firmyl connected together in the region of said vertices.

For each duct, a further gutter may be provided positioned to capture precipitations draining down the upwardly facing surface of the upper section of said other opposite pair of walls defiing the duct which is exposed internally of the duct, said further gutters leading outside said housing.

Alternatively, said upper and lower inclined sections may define gaps between overlapping portions thereof to lead precipitations draining down the upwardly facing surfaces of the upper sections of said other opposite pairs of duct defining walls onto said upwardly facing surfaces of the lower sections of said other opposite pairs of duct defining walls.

For the preferred application of the ventilator to industrial buildings, for example workshops or machine shops which are sources of considerable noise, sound-absorbing material may be provided on the internal, downwardly directed surfaces of said lower and/or upper inclined sections of said other opposite pairs of duct walls.

Specific embodiments of the present invention will now be described by way of example and not by way of limitation with reference to the accompaying drawings in which: Fig. 1 is an operational diagram of a ventilator according to the invention in the form of a cross-section through the ventilator comprising four ducts for the passage of exhaust air, Fig. 2 is a front elevation of a ventilator according to the invention comprising three ducts for the passage of exhaust air, Fig. 3 is a longitudinal section through the ventilator shown in Fig. 2, Fig. 4 is a top view of the ventilator shown in Figs. 2 and 3, Figs. 5, 6 and 7 show top views of modified embodiments of ventilator according to this invention, Fig. 8 is a cross-section through a further embodiment of ventilator of the the invention, Fig. 9 is an operational diagram of a still further embodiment of ventilator according to the invention in cross-section, Fig. 10 is a longitudinal section through the ventilator shown in Fig. 9, Fig. 11 is a cross-section through a still further embodiment of ventilator according to the invention, Fig. 12 is a cross-section through a still further embodiment of ventilator of the invention, and Fig. 13 is a longitudinal section through the ventilator of Fig. 12.

With reference now to the accompanying drawings, in Fig. 1, there is generally designated by 1 a horizontal roof aperture over which a housing 2 of the ventilator is superimposed. In the example shown, four ducts 3a, 3b, 3c and 3d are provided within the housing 2 for the passage of exhaust air from the interior of the building through the roof opening 1. The ducts 3a to 3d are laterally bounded on one pair of opposite sides by walls 4, 41 having two sections 15, 16 disposed in corresponding V-formation, and on another pair of opposite sides by substantially plane, vertical walls 5, which simultaneously form an opposite pair of walls of the housing 2, which is completed by another pair of opposite walls 6 exten ding in the direction of the duct walls 4.The duct walls 4 bound, together with the duct walls 5, on which they are fixed in a suitable manner, lower air inlet apertures 7 and upper air outlet apertures 8, located verti cally opposite to the latter, for the exhaust air emerging from the interior of the building through the roof opening 1 and flowing through the ducts 3a to 3d. At 9 there are illustrated mounting flanges of the housing 2 by means of which the latter is secured to edge areas of the roof opening 1, as illus trated at 10.

The sections of the duct walls 4 adjacent the lower and upper inlet and outlet aper tures respectively are parallelly disposed and the vertices 13 of the walls 4 lie approxi mately midway up the ducts 3a to 3d and are staggered in the transverse direction with respect to the lower and upper edges 14 of the walls 4 by an amount equal to the width of the air inlet and air outlet apertures 7, 8 measured in the direction of stagger between the walls 4. The ducts 3a to 3d are combined in the housing 2 in one unit, wherein each duct wall 4 is common to two adjacent ducts 3a to 3d.

The sections 15 and 16 of the duct walls 4 are formed by individual plates which are .disposed vertically one above the other and which are firmly connected together in the region of their vertex 13. In this example, each individual wall section 15, 16 has an identical cross-sectional shape in the form of a channel-section, whose walls 17 are pro vided with inturned flanges 18 directed to wards one another and extending parallel to the floor of the channel. The upper wall 17 of the lower section 16 is firmly connected, for example riveted, to the floor of the upper section 15 in the region of the vertex 13. In the example shown, only the lower section 161, which is disposed adjacent the left hand side wall 6 of the housing 2 in Fig. 1 and bounds the duct 3a, and the upper sec tion 151, which is disposed adjacent the right hand side wall 6 of the housing 2 in Fig. 1 and bounds the duct 3d, are, for con nection to the respective side wall 6, devoid of any channel wall 17 and flange 18 in the region of its lower edge 14 and its associated vertex 13 respectively.

While the walls 17 with their flanges 18 only contribute to a reinforcement of the individual sections 15, 16, at the lower edges of the upper sections 15, rain gutters 19 are formed by the walls 17 and flanges 18 of the upper sections 15 in the region of the vertices 13 and by the walls 17 and flanges 18 at the lower edges of the lower sections 16. For any given duct wall 4, the rain gutter 19 at the lower edge of its upper section 15 is associated with the duct, for example the duct 3c, to the right hand side of the wall in Fig 1 and the rain gutter at the lower edge of its lower section 16 is associated with the adjacent duct, for example the duct 3b to the left hand side of the wall in Fig. 1.

In the case of the two external duct walls 41 adjoining the walls 6 of the housing 2, it is only the upper section 15 of the duct wall 41 associated with the duct 3a and the lower section 16 of the duct wall 41 associated with the duct 3d which is provided with a rain gutter 19. The gutters 19 lead outside the housing 2.

In Fig. 1, the sound insulation achieved by deflection and reflection of the sound waves in the area of the duct 3a is symbolised by the arrows 20, which get weaker in the sound outlet direction. The weather protection against precipitations brought about by the covering of the air inlet and air outlet apertures 7, 8 by the sections 15, 16 of the walls 4 is illustrated by broken lines 21 in the area of the duct 3c, a portion of the rain water being collected and drained into the rain gutters 19 at the lower edges of the upper sections 15 and further water, including any splashing rain water, by the rain gutters 19 at the lower edges of the sections 16. On the other hand, the deflection of the exhaust air is illustrated by the arrows 22 in the area of the duct 3d.

In the exemplified embodiment shown in Figs. 2 to 4, the housing 21, within which three ducts 3a, 3b, 3c are formed for the passage of the exhaust air, is provided with an opposite pair of vertical walls 51 corresponding to the walls 5 in Fig. 1 and an opposite pair of walls corresponding to the walls 6 having upper and lower sections disposed in corresponding V-formation to the duct walls 4, 41, the walls of the housing 21 corresponding to the walls 6 in Fig. 1 being formed by the outside walls 41 of the ducts 3a and 3c respectively. This ventilator represents a module or a basic unit, several of which may be placed in abutting alignment, in dependence on the dimensions of the roof opening that is to be covered by the ventilator.

In this embodiment, the duct walls 4, 41 are secured to the housing walls 51 by angle sectioned members 23. The duct wall 41 associated with the duct 3a is formed by two butting individual plate sections 15, 16 but it may be formed in one piece. Only the lower section 16 is provided with a gutter 19 along its lower edge 14, while the upper section 15 is provided along its upper edge with a short downturned reinforcing flange 24. As in the case of the Fig. I embodiment, the duct walls 4 and the duct wall 41 bounding the duct 3c consist of individual sections 15, 16 fixed together in the region of the vertex 13.The sections 15 and 16 respectively forming the outside walls of the ducts 3a and 3c, comprise in the region of the vertex 13, and in the region of the lower edge 14 of the lower section respectively, the rain gutters 19 such as previously described, these being formed by folding the sections.

The housing 21 is superimposed over the roof opening by means of an encircling mounting flange 25, which is firmly connected to the housing. Furthermore, the housing 21 is provided at its upper end with an encircling angular strip 26, in the four corners of which there are detachably fitted, for example by screwing, transport eyes 27 allowing the ventilator to be placed in position over the roof opening using a suitable lifting device.

At the levels of the rain gutters 19, the housing walls 51 are provided with rain gutters 28 which have a channel-shaped cross-section and into which the rain gutters 19 open out by means of holes 29 in walls 51 In the example shown, the rain gutters 28 are open at both ends so as to drain the rain water away onto the outside of the roof. When several basic units are placed side by side with their walls 51 in alignment, their respective rain gutters 28 are also joined.

The duct walls 4, 41 are spaced apart by a modular dimension of R=0.625.m, which defines the width of the ducts 3also 3c between their V-form walls. The width of the duct walls 4, 41 themselves may be chosen as desired, preferably in multiples of the modular dimension R. In the case of the exemplified embodiment shown in Figs. 2 to 4, wherein the width of the duct walls 4, 41 equals B (Fig. 4), the maximum width B expediently is four times the modular dimension R. In the exemplified embodiment shown in Figs. 2 to 4, the length of the ventilator, for superimposition over a roof opening of a correspondingly short dimension, is confined to the measure 3R.By contrast, Fig. 5 illustrates an embodiment for superimposition over an elongated roof opening, for example a ridge opening, in which the duct walls 4, 41 extend transversely to the longitudinal extent of the roof aperture and the length of the ventilator is chosen in accordance with the length of the roof aperture and is made a multiple of the modular dimension R. However, instead of a single elongated structural unit, it is also possible to provide a roof opening like that shown in Fig. 5 with a ventilator which is composed of a plurality of units, such as shown in Figs. 2 to 4, disposed end to end.

The modifications shown in Figs. 6 and 7 illustrate ventilators in which the duct walls 4, 41 extend in the longitudinal direction of the roof opening. The chosen multiple of the modular dimension R between the duct walls 4, 41 defines the width B of the ventilator and is, in the example shown in Fig. 6 there times the modular dimension, but it may be chosen as desired, in accor dance with the width of the roof aperture Practically no limits are set to the length of the duct walls 4, 41 which, in turn, is ex pediently dimensioned in multiples of the modular dimension R, as is illustrated in Fig. 7; however, for very long roof openings it may be advantageous to provide duct partitions, extending transversely between the duct walls 4, 41 to stiffen them.

The arrangement of the duct walls 4, 41 in the modular dimension R=0.625 m and the dimensioning of their length in multiples of the modular dimension R makes it pos sible, without difficulty, to mount the ventilators over roof openings which, in industrial buildings, are usually constructed to the same modular dimensions.

In the exemplified embodiments shown in the drawings, the duct wall 4, 41 consist of sheet metal parts, whose surfaces internal to the ducts and mores especially on the sides of the duct walls 4, 41 which are directed downwardly, may in some cases be additionally provided with sound-absorbing material in the form of facing blocks, for example of plastics material or plastics foam, for a further improvement of the sound insulation.

This possibility for providing additional sound insulation by using sound-absorbing materials is illustrated in Fig. 8 The ventilator shown therein is identical with the exemplified embodiment shown in Figs. 2 to 4, but the internal downwardly directed surfaces of the lower sections 16 of the walls 4, 41 are additionally provided with sound absorber blocks 30. The sound absorber blocks 30 are made for example of glass or rock wool, and are secured to the sections 16 in any suitable manner. The sound passing from the interior of the building through the roof aperture 1 is additionally attenuated by the sound absorber blocks 30 through an absorption of the sound waves, which may be increased still further by also providing the upper sections 15 of the duct walls 4, 41, on their internal downwardly directed surfaces, with such sounmd absorber blocks 30. In the arrangement shown in Fig.

8. the sound absorber blocks 30 are protected from moisture caused by precipitation.

In Fig. 9, there is again shown at 1 a horizontal roof aperture in a flat roof 200, to which a horizontal flange 103 of a surrounding mounting 104 of a housing of a ventilator, designated by 105 as a whole, is firmly connected. A vertical wall section 107 os the mounting 104 lines the roof aperture 1 at its edges in the upper region thereof. A further horizontal wall section 108 of the mounting 104 is overlapped by roofing material 109. An upstand 110 of the mounting 104, having a horizontal flange 111, carries the lower rain gutters 112 of the 'ventilator 105.

In the embodiment shown in Figs 9 and 10, there is illustrated only one end of the ventilator 105, which is continued in accor dance with the length of the roof aperture 1, to the right in Fig. 9, only four ducts 113a, 113b, 113c and 113d of the ventilator 105 being shown in Fig. 9 for the passage of exhaust air upwardly through the roof aperture 1 from the building interior. These ducts again have walls 161, 1611 composed of upper and lower sections disposed in corresponding V-formation but vertices are not actually defined in this case. The pro jection of the planes of the sections of the walls, i.e. the imaginary vertices, still lie approximately midway between the ducts, however.

In the present example, gutters 1121 oc cupy the positions of the vertices and these, like the row of gutters 112, have a U-like basic shape in cross-section; however, they may have any other suitable gutter form that is open at the'top and may, for example, be semicircular or V-shaped in corss-section.

The upper edges of the side walls 114 of the gutters 112, 1121 are provided with horizontal flanges 115, which carry substantially plane vertical housing side wall portions 116, 1161 at opposite sides of the ducts 113. The housing side wall portions 116, 1161 are secured to the gutters 112, 1121 by means of horizontal flanges 116a provided on the walls. The ducts 113a to 113d are bounded by parallel duct wall.portions 117, 1171 defining the sections of the walls 161 and these are formed by laminae or plates 118, 1181 disposed at an angle of 45 in the example shown.

The laminae 118, 1181 are secured to the housing side wall portions 116, 1161 in a suitable manner, for example, by means of flanges or angle members. The lower edges of the laminae 118, 1181 are formed on vertically downwardly directed edge portions 119 which extend downwardly into the rain gutters 112, 1121 between the gutter walls 114. The upper edges of the laminae 118, 1181 are staggered relative to their edge portions 119 by an amount greater than but approximately equal to the width of the ducts 113 measured in a horizontal crosssectional plane between adjacent duct walls 161. 1611.

The housing side wall portions 116, 1161, which are secured by means of their lower horizontal flanges 116a to the horizontal flanges 115 of the gutters 112, 1121, also comprise at their upper ends horizontal flanges 116b and the flanges 116b of the wall portions 116 in the exemplified embodiment shown in Figs. 9 and 10, carry the upper row of gutters 1121. The upper edges of the laminae 118 have horizontal flanges 120 which engage under the gutters 1121.

In the example shown, a vertical flange 121 adjoins each horizontal flange 120, the vet- tical flanges 121 forming the free upper edges of the laminae 118.

The gutters 1121 correspond in size and shape with the gutters 112 and carry in turn the vertical housing side wall portions 1161 in the same plane as the housing side wall portions 116. The laminae 118' 'are of the same size and shape as the laminae 118.

These are in turn secured to the housing side wall portions 1161, the laminae 1181 being however inclined oppositely relative to the laminae 118. Only the endwise lamina 118 has a different shape, the vertical flange 1191, which otherwise forms the lower edge portion 119, being lengthened to enable it to be fastened to the vertical flange 121 of the lamina 118 adjoining it at the bottom, so as to form in this manner, a housing side wall of the housing containing the ducts 113.

Within the limits set by a practicable height of construction of the ventilator 105, it is possible to provide it with further banks of laminae 118 and 1181 disposed upwardly in corresponding V-formation, with the interposition of gutters such as 112 and 1121 between adjacent banks, and by using further housing side wall portions such as 116 and 1161 to extend these side walls upwardly. For example, in the exemplified embodiment shown in Figs. 9 and 10, there may be secured to the upper horizontal flange 11 6b of the housing side wall portions 1161'further gutters which again carry duct side wall portions with laminae in an alignment such as that shown for the laminae 118 in Fig. 9.

There would thus be formed zigzag-shaped ducts 113 for the exhaust air, in which the air flow path would be twice deflected.

In Fig. 9, the flow path of the exhaust air entering the ventilator upwardly through the roof aperture 1, due to natural or forced convection, is illustrated by arrows in the two central ducts 113, the narrowest width dimension of each air inlet aperture 7 being defined by the distance between two adjacent gutters 112 and the narrowest width of each air outlet aperture 8 of the ducts 113 being defined by the distance between the vertical flanges 121 and the adjacent upper edges of the upper laminae 1181. Furthermore, shown in Fig. 9 in the endwise duct 113 by broken lines, are the courses of the water originating from falling rain and the collection of the rain water in the gutters 112, 1121. Both vertical flange portions of the upper lannnae, 1181 provide drip edges.

As-can be seen in Fig. 10, the gutters 112, 1121 are led to the outside of the side walls 116, 1161 their ends being open. The open ends of the gutters 112, 1121 as well as' ttik Open clearances between them in the vertical planes of the housing side wall portions 116, 1161, are covered by sheet metal strips 122, which extend along the entire housing pyer the length of the housing side walls 116,- 1161 and are releasably secured to these walls 116, 1161 by means of a vertical flange 123. The detachable fastening of the strips 122 allows them to be removed to clean the gutters 112, '1121 from the open ends thereof.Instead, the strips 122 may be',, formed of flexible plastics material or an elastomeric material, whereby access to the gutters 112, 1121 is made possible for cleaning purposes by just bending the strips 122 upwards. Between the downwardly extending portion 122a of the strips and the open ends of the gutters 112, 1121, a space is provided to allow unhindered draining of the rain water onto the outside of the roof 200.

The embodiment shown in Fig. 11 differs from that shown in Figs. 9 and 10 in that there is associated with each of the laminae 118, 1181, on its internal downwardly directed surface, a sound absorber block 129.

The sound absorber blocks 129 are formed of sound insulating material consisting e.g.

of glass or rock wool and are fastened to the laminae 118, 1181 in any suitable manner.

It goes without saying that, depending on the sound insulation effect to be achieved, it. is also possible to provide only the laminae 118 with sound absorbing blocks 129. In any event, in the arrangement shown in Fig.

11, the sound absorber blocks 129 are protected from precipitation or rain water, which drains downwardly substantially over the surfaces 130 of the laminae 118, 1181 that is remote from the sound absorber blocks 129 and passes into the gutters 112, 1121. In order-to ensure a reliable collection of the rain water in the gutters 112, 1121, the laminae 118, 1181 have on their surfaces 130 a downward step 131, whereby the surface 132 of the laminae 118, 1181 adjoining the gutters 112, 1121 is lowered to allow for a substantially central positioning of the edge portions 119 of the laminae 118, 1181 and therefore the drip edges, in the gutters 112, 1121.The upper horizontal flanges 120 with their adjoining vertically depending flanges 121, which also form drip edges, also contribute to the protection of the sound absorber blocks 129 against damage by water since the flanges overlap the sound absorber blocks 129 at their top edges.

In Fig. 11, the roof aperture 1 and the ventilator 105 superimposed thereover are shown full length. The housing side wall of 'the ventilator 105 at the left hand end in this Figure is formed by the upper lamina 11811 and the adjoining lower lamina 118 which is devoid of a sound absorber block 129 inasfar as this lamina does not have an internal, downwardly directed surface, and the housing side wall at the right hand of the ventilator in Fig. 11 is formed by the upper lamina 1181, which is also devoid of a sound absorber block 129, and by the adjoining gutter 1121 and lower lamina 118. The housing side walls 116, 1161 of the ventilator 105, are shape in their two end regions in accordance with the inclination of the laminae 118, 1181 and 1181l respectively.Such an obliquity of the housing side walls 116, 1161 in the end areas thereof is also provided in the.exemplified embodiment shown in Figs. 9 and 10. However, it is obvious that the housing side walls 116, 1161 may also be squared off in their end areas and be con nected to housing side walls of the duct walls.

.The ventilator.shown in Figs. 12 and 13 has a housing 202 superimposed over a roof opening 1 in a roof ridge and running along the ridge.

The housing 202 is symmetrical about the line of the ridge, that is to say, the vertical centre line V of its cross-section as it appears in Fig. 13. The laminae 218, 2181 at the two sides of the ventilator (which in fact form its ends) do not form part of the housing 202. The two sides 202 of the housing, which extend across the roof ridge, at or towards opposite ends of the ridge, are formed separately of the laminae in this case, and are united with the housing side walls 216 which extend parallel with the roof ridge and each of which is formed without an intermediate gap between upper and lower portions as in the previous embodiment.

Instead of providing the gutters 1121, a gap 201 is defined by correspondingly curved, overlapping portions 218a and 218a' of the lower and upper laminae respectively, these portions curving in conformity with one another and with the vertices formed on the lower laminae, (these again being imaginary in this case), so as to lead rain water falling onto the upwardly directed surfaces of the upper laminae 2181 onto the upwardly directed surfaces of the lower laminae 218 from'which it drains into the gutters 212 provided at the lower edges of the lower laminae.The gutters 212 have floors which slope outwardly in both directions from the vertical central transverse plane of sym metry which includes the axis V, the gutters passing beneath the lower edges of the walls 216 and their open ends discharging water respectively into gutters or.-conduits 204 defined, in part, by removable plates 205 to allow access to the gutters 212 for cleaning.

The conduits 204 discharge at . their two 'ends respectively onto the outside of' the roof structure or into rain water down pipes.

To maintain the symmetry of the arrangement some space is wasted inside the housing 202 as may be seen at the right hand side in Fig. 12. This does not detract from the area of the ventilation opening provided by the ventilator however which remains the same as that of the opening 1 in the roof structure.

The upper lamina 2181 at the left hand side in Fig. 12 defines a restricted outlet aperture 206 at the top with the left hand side 2021 of the housing and rain water entering this aperture is drained through the gap 201 between the lamina and its associated lower lamina 218 into its gutter 212.

The undersides of the first laminae 218 or the undersides of the laminae 218 and 218 may be lined with sound attenuating and absorbing blocks or equivalent lining material and su'ch blocks, if provided on the under side of the laminae 2181, may be sheltered from precipitations at their upper edge by suitable capping flanges. Preferably, however, such blocks or lining are confined to the underside of the laminae 218.

Adjacent laminae 218 and 2181 are parallel and equally spaced and the imaginary vertices referred to are positioned approximately midway between the inlet apertures 7 and the outlet apertures 8 of the ducts formed between adjacent, V-formed pairs of lam,inae. The laminae 218 and 2181 extend at right angles to one another at 45" to the vertical direction. The vertices of the respective V-formed pairs of laminae are staggered with respect to the lower edge of the lamina 218 and the upper edge of the lamina 2181 by more than the width dimension of the inlet apertures 7 and the outlet apertures 8 as measured between the gutters 212 and the upper edges of the laminae respectively.

The ventilator of Figs. 12 and 13 therefore functions to provide natural ventilation for a building whilst preventing the entry of weather and at the same time attenuates the sound emerging from the building in the same manner as has been described for the earlier embodiments.

The arrangement of the upper and lower laminae 218, 2181 with intermediate gaps 201 formed in the region of the vertices in substitution for gutters at this location may be employed in all the earlier described embodiments of the ventilation system described herein.

Corresponding parts in the various em bodiments- - are indicated by corresponding reference numerals where not otherwise described.

WHAT WE CLAIM IS:- 1. A roof ventilator mounted on a building over a horizont,al - or - slightly in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

'the ventilator 105 at the left hand end in this Figure is formed by the upper lamina

11811 and the adjoining lower lamina 118 which is devoid of a sound absorber block

129 inasfar as this lamina does not have an internal, downwardly directed surface, and the housing side wall at the right hand of the ventilator in Fig. 11 is formed by the upper lamina 1181, which is also devoid of a sound absorber block 129, and by the adjoining gutter 1121 and lower lamina 118. The housing side walls 116, 1161 of the ventilator 105, are shape in their two end regions in accordance with the inclination of the laminae 118, 1181 and 1181l respectively.Such an obliquity of the housing side walls 116,

1161 in the end areas thereof is also provided in the.exemplified embodiment shown in Figs. 9 and 10. However, it is obvious that the housing side walls 116, 1161 may also be squared off in their end areas and be con nected to housing side walls of the duct walls.

.The ventilator.shown in Figs. 12 and 13 has a housing 202 superimposed over a roof opening 1 in a roof ridge and running along the ridge.

The housing 202 is symmetrical about the line of the ridge, that is to say, the vertical centre line V of its cross-section as it appears in Fig. 13. The laminae 218, 2181 at the two sides of the ventilator (which in fact form its ends) do not form part of the housing 202. The two sides 202 of the housing, which extend across the roof ridge, at or towards opposite ends of the ridge, are formed separately of the laminae in this case, and are united with the housing side walls 216 which extend parallel with the roof ridge and each of which is formed without an intermediate gap between upper and lower portions as in the previous embodiment.

Instead of providing the gutters 1121, a gap 201 is defined by correspondingly curved, overlapping portions 218a and 218a' of the lower and upper laminae respectively, these portions curving in conformity with one another and with the vertices formed on the lower laminae, (these again being imaginary in this case), so as to lead rain water falling onto the upwardly directed surfaces of the upper laminae 2181 onto the upwardly directed surfaces of the lower laminae 218 from'which it drains into the gutters 212 provided at the lower edges of the lower laminae.The gutters 212 have floors which slope outwardly in both directions from the vertical central transverse plane of sym metry which includes the axis V, the gutters passing beneath the lower edges of the walls

216 and their open ends discharging water respectively into gutters or.-conduits 204 defined, in part, by removable plates 205 to allow access to the gutters 212 for cleaning.

The conduits 204 discharge at . their two 'ends respectively onto the outside of' the roof structure or into rain water down pipes.

To maintain the symmetry of the arrangement some space is wasted inside the housing 202 as may be seen at the right hand side in Fig. 12. This does not detract from the area of the ventilation opening provided by the ventilator however which remains the same as that of the opening 1 in the roof structure.

The upper lamina 2181 at the left hand side in Fig. 12 defines a restricted outlet aperture 206 at the top with the left hand side 2021 of the housing and rain water entering this aperture is drained through the gap 201 between the lamina and its associated lower lamina 218 into its gutter 212.

The undersides of the first laminae 218 or the undersides of the laminae 218 and 218 may be lined with sound attenuating and absorbing blocks or equivalent lining material and su'ch blocks, if provided on the under side of the laminae 2181, may be sheltered from precipitations at their upper edge by suitable capping flanges. Preferably, however, such blocks or lining are confined to the underside of the laminae 218.

Adjacent laminae 218 and 2181 are parallel and equally spaced and the imaginary vertices referred to are positioned approximately midway between the inlet apertures 7 and the outlet apertures 8 of the ducts formed between adjacent, V-formed pairs of lam,inae. The laminae 218 and 2181 extend at right angles to one another at 45" to the vertical direction. The vertices of the respective V-formed pairs of laminae are staggered with respect to the lower edge of the lamina 218 and the upper edge of the lamina 2181 by more than the width dimension of the inlet apertures 7 and the outlet apertures 8 as measured between the gutters 212 and the upper edges of the laminae respectively.

The ventilator of Figs. 12 and 13 therefore functions to provide natural ventilation for a building whilst preventing the entry of weather and at the same time attenuates the sound emerging from the building in the same manner as has been described for the earlier embodiments.

The arrangement of the upper and lower laminae 218, 2181 with intermediate gaps 201 formed in the region of the vertices in substitution for gutters at this location may be employed in all the earlier described embodiments of the ventilation system described herein.

Corresponding parts in the various em bodiments- - are indicated by corresponding reference numerals where not otherwise described.

WHAT WE CLAIM IS:- 1. A roof ventilator mounted on a building over a horizont,al - or - slightly in

clined roof aperture, the ventilator.com- prising an open topped and open bottomed housing having two opposite pairs of side walls, a downwardly directed air inlet aperture at its lower end, opening to said roof aperture, and an upwardly directed air outlet aperture at its upper end, opening directly to the outside of the building, there being a plurality of upwardly extending air ducts defined in the housing for the passage of exhaust air, each duct comprising an air inlet aperture at its lower end, opening to said housing air inlet aperture, and an outlet aperture at its opposite, upper end, opening to said housing air outlet aperture, each duct being defined between two opposite pairs of side walls one pair of which are vertically disposed and the other pair of which comprise inclined upper and lower sections disposed in corresponding V-formation, the vertices of said other opposite pair of side walls being staggered with respect to the lower and upper edges of those walls by an amount not less than the width of the duct air inlet aperture and the duct air outlet aperture respectively, measured in the direction of said stagger, and for each duct, a gutter positioned to capture precipitations draining down the upwardly facing surface of the lower section of said other opposite pair of walls defining the duct which is exposed internally of the duct, said gutters leading outside said housing.
2. A ventilator as claimed in claim 1 wherein said inclined sections are disposed at right angles to one another.
3. A ventilator as claimed in claim 1 or 2 wherein the inclined sections are formed by individual plates which are fixed together in the region of said vertices.
4. A ventilator as claimed in any preceding claim wherein for each duct a further gutter is provided positioned to capture precipitations draining down the upwardly facing surface of the upper section of said other opposite pair of walls defining the duct which is exposed internally of the duct, said further gutters leading outside said housing.
5. A ventilator as claimed in any preceding claim wherein one of said other pair of opposite side walls of each duct is common to another of said ducts.
6. A ventilator as claimed in claims 4 and 5 wherein of the gutters associated with each of said other pair of opposite side walls of each duct, the upper section gutter is positioned in one duct and the lower section gutter is positioned in an adjacent duct.
7. A ventilator as claimed in any preceding claim wherein one opposite pair of side walls of the housing is formed by one each of two of said other opposite pairs of duct defining walls.
8. A ventilator as claimed in any preceding claim wherein one opposite pair of side walls of the housing is formed at least in part by the vertically disposed duct side walls.
9. A ventilator as claimed in any preceding claim wherein the gutters open out through at least one of the vertically disposed duct side walls to a further gutter or gutters provided on the outside of said wall.
10. A ventilator as claimed in claims 8 and 9 wherein the ends of the gutters opening out through a housing side wall are overlapped by a protective strip or strips extending along the wall.
11. A ventilator as claimed in any preceding claim wherein sound absorbing material is provided on the internal, downwardly directed surfaces of said lower and/or upper inclined sections of said other opposite pairs of duct walls.
12., A ventilator as claimed in claim 1 or 2 wherein said upper and lower inclined sections define gaps between overlapping portions thereof to lead precipitations draining down the upwardly facing surfaces of the upper sections of said other opposite pairs of duct defining walls onto said upwardly facing surfaces of the lower sections of said other opposite pairs of duct defining walls.
13. A ventilator mounted on a building over a horizontal or slightly inclined roof aperture, substantially as hereinbefore described with reference to Fig. 1 or Figs. 2, 3 and 4 or Fig. 5 or Fig. 6 or Fig. 7 or Fig.

8 or Figs. 9 and 10 or Fig. 11 or Figs. 12 and 13 of the accompanying drawings.