GB2041514A - A wall box assembly for connection to the end of a flat ventilation duct - Google Patents

Abstract

A wall box assembly for connection to the end of a flat ventilation duct (14) includes a ventilation grill (11) and transition piece (12). The expression "flat duct" includes a duct of rectangular, elliptical or oval cross-section. The transition piece (12) contains a non-return valve (16) opening only to the weather side (7). In the region of the valve, the transition piece has a stop (13) projecting radially inwardly. Telescopically slidably up to the stop, the transition piece (12) may either receive a piece (20) or directly receive the end of the ventilation duct (14). The assembly may also include a wall connecting piece (21) which is interconnected either with the transition piece (12) of the telescoping piece (20) and with the ventilation duct (14). The cross-sectional shape of the transition piece (12) is flat and geometrically similar to the cross-sectional shape of the ventilation duct in every cross-sectional plane thereof. <IMAGE>

Description

SPECIFICATION A wall box assembly for connection to the end of a flat ventilation duct This invention relates to a wall box assembly for connection to the end of a flat ventilation duct of a vapour exhaust housing. Such an assembly can comprise a ventilation grill and a transition piece connectable therewith, the transition piece being formed as a backwash housing and having in its interior a non-return valve opening only to the weather side and closing to the building side, in the region of the valve the transition piece having a stop projecting radially inwardly and a succeeding tubular element being telescopically slidable within the transition piece up to the stop.

A wall box assembly of this type is known through general use and consists, in its basic conception, of a rectangular ventilation grill, which is secured by screws onto a transition piece. The transition piece has, at its end adjacent to the ventilation grill, a square cross-sectional shape and, at its end adjacent to the ventilation duct, a circular cross-sectional shape. At the transition point between circular and square cross-sectional shape there is arranged a non-return valve of approximately circular form which opens only to the weather side and closes to the building side of the asssembly. This shape of wall box is known from the drawing of German Gebruachsmuster No 70 48 151.

A plastic pin is inserted as a stop into the wall box part with circular cross-section at a point close to the non-return valve. A second transition piece is telescopally slidable into the circular cross-section of the first transition piece up to the radially inwardly extending plastics pin. This second transition piece with corresponding circular cross-section is provided at its end remote from other parts of the wall box assembly with several step-like reducing circular annular cross-sections.In order to be able to connect the known wall box assembly with its first and second transition pieces to a flat ventilation duct of a vapour exhaust housing, a third transition piece is necessary which has, at its one end, a corresponding circular cross-section surrounding the step-like end of the second transition piece and, at its other end, a cross-section corresponding in its configuration approximately to the cross-section of the flat ventilation duct, with which it can finally be secured by way of a coupling piece. By a "flat" ventilation duct one understands such a duct having a rectangular, elliptical or oval cross-section.

The wall box of the previously identified type described above and known through public use has the disadvantage that it, on the one hand, requires two further transition pieces as well as the coupling piece for its connection to the end of a flat ventilation duct of a vapour exhaust housing and, on the other hand, in its end region extending over the associated upper cupboard, does not lie snugly over the whole length of this upper cupboard. Furthermore it is disadvantageous that, at the point at which the third transition piece extends in the direction of flow over the second transition piece, the "furnace tube principle" is lost and exhaust air can escape at this point. In addition, the throttled point resuiting therefrom through the reduction of the flow cross-section, leads to additional pressure loss.

Such wall box assemblies find use particularly in kitchens in which the steam, smoke and the like, known in short as exhaust air collected by a fume exhaust housing must be led into the atmosphere. Therein, generally speaking the relevent ventilation ducts fitted together by plug-like connections are arranged over the upper surfaces of the upper cupboard of the associated kitchen furniture. Since these ventilation ducts should be arranged as far as possible in a non-displeasing manner from the visual viewpoint, a circular duct cross-section is optically unsatisfactory because of its constructional height, although satisfactory from a technical flow, and also a constructional, point of view. Furthermore, a circular shape requires substantially greater space in its storage, its transport and its installation as against a flat duct shape.On the other hand, for the same cross-sectional surfaces, a circular tube on a kitchen top cupboard is more visually obvious than a socalled flat duct having a rectangular, elliptical, or oval cross-section, of which the long side of the cross-sectional shape overlies the upper surface of the cupboard. The critical point of the wall box assembly being discussed here with respect to its connection to the end of a flat ventilation duct of a vapour exhaust housing lies in the region of the wall opening on the inner side of the relevant room, that is at the point at which the wall box must be connected to the flat ventilation duct.

At this point the invention is involved. The basis thereof is to create a wall box assembly of the aforementioned type which is securable to the ventilation duct with small assembly and material expense, which ensures a precise layout of the ventilation duct over the whole length over the upper cupboard and, with which, the escape of exhaust air as well as additional pressure losses through throttling in the region of the connection point are avoided.

In accordance with the invention there is provided a wall box assembly for connection to the end of a flat ventilation duct of a vapour exhaust housing and comprising a ventilation grill and a transition piece connectable therewith, the transition piece being constructed as a backwash housing and having in its interior a non-return valve opening only to the weather side and closing to the building side, in the region of the valve the transition piece has a stop projecting radially inwardly and a succeeding tubular element being telescopically slidable with the transition piece up to the stop, the cross-sectional shape of the transition piece being flat and geometrically simular to the cross-sectional shape of the ventilation duct in every cross-sectional plane thereof.

As a result of the construction a direct connection of the end of a flat ventilation duct with the wall box assembly is possible without the hitherto necessary additional transition pieces and additional coupling piece being required. Furthermore, with this construction exhaust air can no longer escape and no throttling points, resulting in additional pressure losses are present. Thus, now the succeeding tubular element is identical with the end of the flat ventilation duct and as such is directly telescopically slidable into the wall box. This embodiment of the wall box assem bly is equally suitable for subsequent installation in the basic walls of a building already constructed.If the new wall box assembly, on the other hand, is to be introduced ready for connection during the construction of buildings and not to require chisel work, it has in accordance with an advantageous construction a telescoping piece corresponding with the ventilation duct in the size and shape of the cross-sectional surfaces and a wall connecting piece located between the transition piece and the end of the ventilation duct, of which the wall connecting piece fits into the telescopic piece by way of a sleeve-like, radially and axially inwardly directed, dog leg portion and is secured to the telescoping piece.In this construction a spacial shape is created in accordance with the "concertina principle" which in addition to the aforementioned advantages ensures a relatively large length change and acceptance capability of the whole wall box assembly to different wall thicknesses without difficulty.

In this embodiment it is advantageous if the free internal cross-sectional face of the dog leg portion is only slightly smaller than the free internal cross-sectional face of the end of a ventilation duct slidable into the wall connection piece from the other end thereof remote from the dog leg portion. In this construction the dog leg portion serves as a stop for the end of the flat ventilation duct slid directly inwardly into the wall connection piece while providing an approximately constant flow cross-section.

Two embodiments of the invention are described below with respect to the accompanying drawings in which: Figure 1 is a perspective external view of a simpler embodiment of a wall box assembly secured to the end of a flat ventilation duct, Figure 2 is a cross-section though the wall box assembly of Fig. 1 after its installion in a wall opening, Figure 3 is a perspective external view of a further embodiment of wall box assembly having a wall connection piece and a telescopic piece arranged between the transition piece and the ventilation duct, and Figure 4 is the embodiment of the wall box of Fig. 3 in longitudinal section after its installation in a wall opening.

A wall box assembly according to Figs. 1 and 2 comprises a ventilation grill 11 and a transition piece 1 2 whose one end 12' encloses the small connection stub 1 5 of the ventilation grill 11 and whose other end 12" surrounds the end 14 of the ventilation duct.

In the present case the transition piece 1 2 is formed as a backwash housing and has a nonreturn valve 1 6 in its inner space 12"' which opens only to the weather side 7 and closes to the building side 8. At the location of this non-return valve 1 6 the transition piece 12 is provided on its inner side with a radially inwardly projecting stop 1 3 against which the end of the ventilation duct 14 fits snugly by way of its forward face 14' in its inwardly slid position.

As is particularly apparent from the perspective external view of Fig. 1 in connection with Fig. 2, the embodiment is characterised in that the cross-sectional shape of the transition piece 1 2 is geometrically similar in every cross-section plane to the cross-sectional form of the ventilation duct 14 and the end of the ventilation duct 14. The relationship of the objects of the invention to this solution were discussed previously on the introduction to the description.

As a result of this solution, on the one hand, the parts represented by the additional transition pieces and the coupling piece always present in this zone in the prior art can be dispensed with and, on the other hand, a snug fitting of the flat ventilation duct on the adjacent upper cupboard is obtained over the whole end zone. Furthermore, the escape of exhaust air, as well as throttling points is avoided.

The non-return valve 1 6 consists of several known plates arranged one above the other as well as being pivoted along their upper longitudinal edges 16'. These plates are to open only to the weather side 7 and to close to the building side 8.

This wall box is, because of its. simple construction and its simple assembly, particularly suited in general where such a wall box is to arranged subsequent to the original construction in an opening 9 of a main building wall 10.

A further embodiment of the wall box assembly of the invention as well as its connection to the end of a flat ventilation duct are illustrated in Figs. 3 and 4. Parts corresponding to those of Figs. 1 and 2 are provided with the same reference numerals. In addition to the ventilation grill 11 and the transition piece 12, which in shape and construction correspond to those of Figs. 1 and 2, this wall box has a telescopic piece 20 and a wall connection piece 21 as well which are arranged between the transition piece 1 2 and the end of the ventilation duct 1 4. The telescopic piece 20 has an end 20' extending into the end 12" of the transition piece 1 2 adjacent thereto and surrounds the wall connecting piece 21 with its other end 20".The wall connecting piece 21 is provided at its end adjacent to the telescopic piece 20 with a sleeve-like radially and axially inwardly directed dog leg portion 22. This dog leg portion is connected to the adjacent end 20' of the telescopic piece 20 by adhesive. The free internal cross-sectional face of the dog leg portion is only slightly smaller than the free internal cross-sectional face of the end of the ventilation duct 1 4 which is slidable from the other end 21' of the wall connection piece 21 thereinto.In the present case the cross-sectional face and the wall thickness of the telescopic piece 20 correspond in size and shape with the end of the ventilation duct 14 so that the telescopic piece can be constructed in a simple manner from the same extruded material as the end of the ventilation duct 1 4. The end 12" of the transition piece 1 2 and the end 20' of the telescopic piece 20 are slidable relative to each other so that length differences of up to 50mm can be accommodated. It is understood that in the same way this applies to the embodiment of Figs. 1 and 2 in which the end of the ventilation duct 1 4 is slidable relative to the end 1 2" of the transition piece.

In both embodiments of Figs. 1 to 4 the connection stub 1 5 is advantageously connected with the surrounding end 12" of the transition piece 1 2 by an adhesive.

In addition to this improved manipulation and assembly the new wall box has the advantage from the flow technology point of view that it widens out in the flow direction of the exhaust air as a result of its funnel shaped spatial form and accordingly makes the exhausting of the exhaust air easier.

A further adaptance possibility for compensating different thicknesses of building wall 10 is created through the relative slidability of the end of the ventilation duct 1 4 to the wall connection piece 21 so that the transitional engagement of this end in the wall connection piece 21 not only makes the assembly substantially easier but also ensures an optically externally satisfactory impression through its snug location over the whole length of the corresponding upper cupboard.

In the embodiments-of Figs. 1 to 4 all the conduit cross-sections of the individual parts 11, 12, 20, 21 as well as the ventilation duct 1 4 have a rectangular form which advantageously corresponds approximately to or to the multiple of the longitudinal cross-section of a traditional brick. In this way the opening 9 in the building wall 10 can be created in a simple manner through removal of one more bricks.

It is understood that, within the scope of the invention, the wall box assembly and therewith also the ventilation duct does not necessarily have a rectangular form but can also have another flat shape as in an extrudable flat ducting, e.g. an elliptical or oval shape, or be provided with such a crosssection whose sides parallel to each other are connected with each other at their ends through respective half-circle arcs of the same size.

Claims (5)

1. A wall box assembly for connection to the end of a flat ventilation duct of a vapour exhaust housing and comprising a ventilation grill and a transition piece connectable therewith, the transition piece being constructed as a backwash housing and having in its interior a non-return valve opening only to the weather side and closing to the building side, in the region of the valve the transition piece has a stop projecting radially inwardly and a succeeding tubular element being telescopically slidabie within the transition piece up to the stop, the cross-sectional shape of the transition piece being flat and geometrically similar to the cross sectional shape of the ventilation duct in every cross-sectional plane thereof.

2. A wall box assembly according to claim 1 wherein the transition piece is arranged to receive the end of the ventilation duct.

3. A wall box assembly according to claim 1, further comprising both a telescoping piece corresponding with the end of the ventilation duct in size and shape of the cross-sectional surfaces and a wall connecting piece located between the transition piece and the end of the ventilation duct, of which the wall connecting piece fits into the telescoping piece by way of a sleevelike radially and axially inwardly directed dog leg portion and is secured to the telescoping piece.

4. A wall box according to claim 2 wherein the free internal cross-sectional face of the dog leg portion is only slightly smaller than the free internal cross-sectional face of the end of a ventilation duct which is slidable into the wall connecting piece from the other end thereof remote from the dog leg portion.

5. A wall box assembly substantially as hereinbefore described with reference to Figs.

1 and 2 or Figs. 3 and 4 of the accompanying drawings.