Ventilation appliance

A ventilation appliance for rooms having a box-like housing which can be used either as a ventilator with a radial fan or a pressure differential ventilator without such a fan. The configuration of the applicance insures a good sound damping action even when only short flow path are available in the housing or when, for functional reasons, the housing cannot be lined with sound damping material. For this purpose and enveloping spiral 21 for the blower wheel of the radial fan is formed directly from a block-like insert body of sound damping material such a plastic foam or foam rubber, the enveloping spiral having formed thereon an approximately tangential and/or radially connecting air connecting conduit. A replaceable filter for such a ventilation device is disclosed. A possible explanation is indicated for an unexpectedly effective mixing of entering air with room air upon installation of such a ventilating appliance.

BACKGROUND OF THE INVENTION 
This invention relates to a ventilation appliance for rooms with a radial 
fan arranged in a box-shaped housing and an enveloping spiral column 
encircling the blower wheel inside the housing, formed as an insert body. 
In ventilation appliances for rooms it is already known, for example as 
disclosed in DE-OS 30 17 431, to arrange a radial fan in a box-like 
housing the radial fan consisting of the blower wheel itself and encircled 
by an enveloping spiral. The radial fan is detachably arranged in the 
box-like housing. 
A deficiency in known ventilation appliances lies in the fact that both the 
blower wheel and the encircling, enveloping spiral are constructed 
entirely of rigid (reverberative) material, such as sheet metal. 
Significant sound-deadening effect can therefore only be obtained in known 
ventilation appliances when special linings, formed out of sound deadening 
material, are applied to the air conducting conduits at the back of the 
radial fan itself in the box-like housing. 
For functional reasons it is not always possible to provide sound deadening 
linings in the flow ducts at the back of the radial fan. Moreover, there 
is frequently not enough space beyond the radial fan inside the box-like 
housing to arrange sound deadening, lined, flow ducts of sufficient 
lengths to acheive significant sound deadening effect. 
The instant invention has, as a primary objective, to provide a room 
ventilating appliance of the above described type that acheives a good 
sound deadening effect even when no long flow paths are available within 
the box-like housing, or when, for functional reasons, the paths cannot be 
provided with sound deadening linings. 
BRIEF SUMMARY OF THE INVENTION 
The instant invention provides that the enveloping spiral for the blower 
wheel, and an approximately tangential and/or radial ajoining air 
conducting conduit, be directly formed by an insert body made out of sound 
deadening material such as plastic foam or foam rubber. 
A further feature of the invention provides that the wall of the enveloping 
spiral which lies opposite to an air outlet of the housing and is 
connectable with the outside air, comprises a platelike, flat, insert body 
of sound deadening material such as plastic foam or foam rubber. A holder 
plate abuts at the inside of this body, formed of reverberant material on 
which the stator of the radial fan is mounted. By this means, a damping of 
high and low audible frequencies is attained in the operative range of the 
radial fan. 
The invention also involves a particularly favorable configuration of the 
ventilation appliance in which the plate-like, flat, insert body covers 
only that part of the air-conducting conduit that ajoins tangentially onto 
the enveloping spiral. The radial part thereof has a clearance over its 
whole length from the oppositely lying front wall of the housing and/or 
from a sound deadening layer located on the housing. A laterally directed 
flow distribution of air can be obtained which yields another improvement 
of the sound dampening effect. 
A further aspect of the invention is a provision of a favorable flow 
distribution inside of the box-like housing by providing bevels on the 
longitudinal sides of the insert body which contain the enveloping spiral 
and the air conducting conduit. The bevels are provided at least over the 
longitudinal section which contains the radial part of the air conducting 
conduit. The bevels run by acute angles to the neighboring longitudinal 
walls of the housing. 
Air outlets (for example, lattices of perforations) are located at that 
point in the longitudinal housing walls. 
Another important feature of the ventilation appliance of the present 
invention is the provision of a swivel flap as closing and air conducting 
member, at least in the region of the air outlets. Such a flap is provided 
between each longitudinal housing wall and the neighboring longitudinal 
side of the insert body which is inclined thereto. Each such swivel flap 
is supported at the longitudinal housing wall near the rear wall and 
consists of a profile that has two legs lying at an obtuse angle to one 
another. The angular distance of the legs from one another is coordinated 
to the angle between the front face and the longitudinal side of the 
insert body which contains the enveloping spiral and the air conducting 
conduit and which is inclined thereto. 
For the purpose of simple actuation, the invention also provides that each 
swivel flap is adjustable between its closing position and its open 
position by means of a crankpin through a rotary button or toggle that 
engages in a curved slot provided at the free leg of the swivel flap. 
Simplicity of construction is achieved in the ventilation appliance of the 
present invention by the fact that the longitudinal side walls and the 
front wall of the box-shaped housing are formed, in each case, of extruded 
profiles of light metal or plastics. The partitions are constructed as 
formed parts by light metal die-casting or by plastic injection molding. 
The rear wall is a canted-off formed part, stamped out of sheet metal. The 
two longitudinal side walls of the box-shaped housing consist of 
mirror-inverted but otherwise identical, opposed, extruded profiles. The 
front wall is formed by two mirror-inverted, oppositely arranged extruded 
profiles along with a supplementary extruded profile coupling them with 
one another. 
In many cases it is desirable or necessary that the air conveyed by the 
ventilation appliance be freed of particles of dust or noxious matter 
before its introduction to the room. For this reason it has proved 
particularly recommendable to provide a replaceable filter insert, 
comprising a folded or layered body having relatively little space 
requirement in order to provide a large filter surface that can be 
replaced at any time in a simple manner.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The drawings illustrate a ventilation appliance for rooms which is 
particularly suited for arrangement on the inside of building walls; for 
example, in living rooms and work rooms. As can be clearly seen from FIG'S 
1-3 the ventilation appliance is provided with the box-shaped housing 1 
with a housing rear wall 2, two longitudinal housing walls 3' and 3", 2 
transverse housing walls 4' and 4", as well as a front wall 5. In this 
embodiment, the housing rear wall 2 is constructed as a canted-off formed 
part, stamped out of sheet metal which has two longitudinal flanges 2' and 
2". The rear wall is provided in this case with a punched out, circular 
air passage opening 2'" (best seen in FIG. 2). 
The two transverse housing walls 4' and 4" are detachably connected to the 
housing rear wall 2, by means of screws at the opposite transverse edges. 
It is preferable to construct the transverse housing walls 4' and 4" as 
formed parts by light metal die-casting or a plastic injection molding, 
whereby reinforcing ribs may be provided in a simple manner on relatively 
thin walls. The walls are provided with perforations, hollow spaces, and 
chambers for containing electrical switch and installation elements. This 
is illustrated in FIG. 2 in connection with the transverse housing wall 
4". 
The housing rear wall 2 engages with its transverse edges in each case in 
the bead-like shoulders 4'" of the transverse housing walls 4' and 4". 
This is illustrated in FIG. 2 in connection with the transverse housing 
wall 4". This assures an exact alignment of the tranverse housing walls 4' 
and 4" relative to the housing rear wall 2. 
The longitudinal housing walls 3' and 3" are preferably constructed of 
light metal or plastic extruded profiles. These profiles are in each case 
provided with rearwardly extending profile webs 6' and 6" at least along 
or near the longitudinal edges. This can best be seen in FIG. 4. The 
profile web 6' is so shaped that it defines, by means of a hook-like 
profile nose 7', a longitudinal slot 8 which is open towards the 
longitudinal edge 9 of the longitudinal housing walls 3' and 3". The two 
beveled longitudinal flanges 2' and 2" of the housing rear wall 2 engage 
in these longitudinal slots 8 of the longitudinal housing walls 3' and 3", 
as can be clearly seen in FIG'S. 3 and 4. 
Another profile nose 7' of profile web 6' is directed towards the opposite 
side. This nose 7", along with a bead 10 located directly at the inside of 
the longitudinal housing walls, defines a groove 11 having a partial 
circular cross-section as seen in FIG. 4. 
Likewise, profile web 6" is so arranged and developed that, together with a 
bead lying directly at the second longitudinal edge 12 of the longitudinal 
housing 3' and 3", it defines a groove 13, also having a partial circular 
cross-section. Each longitudinal housing wall and 3' and 3" engages, with 
its 2 transverse edges 3'", in bead-like indentations in the transverse 
housing walls 4' and 4". These are designed similarly to the bead-like 
indentations 4'" provided for the transverse edges of the housing rear 
wall 2. 
The housing front wall 5 is composed of several extruded profiles arranged 
parallel to one another and which may likewise consist of light metal or 
plastic. In this case the front wall is formed of at least two extruded 
profiles 5' and 5" which are mirror-inverted and opposed to one another. 
In the illustrated embodiment, the two extruded profiles 5' and 5" are 
coupled with one another through an intermediate, third extruded profile 
5'" as best can be seen from FIG. 3. Moreover, the extruded profiles 5', 
5", and 5'" (or the housing front wall 5 which they form) engage with 
their transverse edges, for security of position, in bead-like 
indentations which lie at the boundary rim of the transverse housing walls 
4' and 4". These correspond to the bead-like indentations 4" as can best 
seen in FIG. 1. In each case the two mirror-inverted, opposed, extruded 
profiles 5" and 5' can be pivoted into the circularly profiled 
longitudinal slots 13 of the longitudinal housing walls 3' and 3" by means 
of coupling webs 14 which are integrally formed on the profiles and which 
have a corresponding partial circular cross-section. This is best seen in 
FIG. 4. These two profiles are then connected through the third extruded 
profile 5'" at the longitudinal edges which face one another. This 
connection is through stop webs 15 and 16 which are designed for 
reciprocal engagement so that the outside surfaces all the extruded 
profiles 5', 5", and 5'" of the housing front wall 5 lie in the same 
plane. The surface passes over, through a radius of curvature to the 
longitudinal housing walls 3' and 3" as shown in FIG. 3. The securely held 
connection, both of the longitudinal housing walls 3', 3", and of all the 
extruded profiles 5', 5", and 5'" of the housing front wall 5, with the 
two transverse housing walls 4' and 4" can be effected simply by means of 
rotatable casement-type locks 17. These may be supported near the 
tranverse edges of the extruded profile 5'" and can be pivoted with their 
tongues into corresponding pockets in the transverse housing walls 4' and 
4" by applying an initial tension. 
The outer surface of the housing rear wall 2 is covered with a 
vibration-damping coating 18 such as a thin layer of elastic/plastic foam 
or foam rubber. This coating is provided in alignment position with the 
air passage opening 2'" of the housing rear wall 2 by means of an 
appropriate cut-out 18'. 
Inside the box-shaped housing, a radial fan 19 is arranged between the 
housing rear wall 2, the two longitudinal housing walls 3', 3", and the 
housing front wall 5 as is best seen in FIG'S. 1 and 2. The radial fan 19 
consists of a blower wheel 20 and an enveloping spiral 21 surrounding it, 
in which an electric motor 22 serves to drive the blower wheel 20. The 
stator 23 of the motor rests on a holding plate 24. The holding plate 24 
for the stator 23 of the electric motor 22 is configured in the interior 
of the box-shaped housing 1 so that the blower wheel 20 is held in axial 
alignment with the air passage opening 2'" in the housing rear wall 2. The 
enveloping spiral 21 of the radial fan 19 is molded directly into a 
block-like insert body 25 which is composed of the sound deadening 
material, such as plastic foam or foam rubber. The insert body 25 also 
contains a section 26 which joins the enveloping spiral 21 in 
approximately tangential manner, and also joining there a section 27 of an 
air conducting conduit 28 directed radially towards the enveloping spiral 
21 and towards the blower wheel 20 (see FIG. 1). 
The aperture area of the enveloping spiral 21 (which lies opposite to the 
air passage opening 2'" in the housing rear walls 2 as well as the 
tangential institutional section 26 of the air conducting conduit 28 which 
follows the enveloping spiral 21) is closed off in the direction of the 
housing front wall 5 by the holder plate 24 on which is attached the 
stator of the electric motor 22 (which drives the blower wheel 20). In 
this preferred embodiment, the holder plate 24 consists of rigid 
(non-absorbing) material, such as sheet metal, and it rests on a 
plate-like flat insert body 29 made out of sound damping material, such as 
plastic foam or foam rubber. This is best shown in FIG. 2. The plate-like, 
flat insert body 29 is thus supported by the housing front wall 5 of the 
box-shaped housing 1. The holder plate 24 is elastically pressed against 
the adjacent front face of the insert body 25 which in its turn rests upon 
the housing rear wall 2. 
The front face of the section of the insert body 25 which faces away from 
the housing rear wall 2 displays a certain clearance 30' or 30" from the 
housing front wall 5 as seen in FIG. 3. This section of the insert body 
contains the section 27 of the air conducting conduit 28 which is 
basically directed radially towards the enveloping spiral 21 or towards 
the blower wheel 20 of the radial fan 19. Thus, at least the areas of the 
housing front wall 5 formed by the extruded profiles 5' and 5" can be 
coated with layers 31' and 31" made out of sound-damping material such as 
plastic foam or foam rubber. The central extruded profile 5'" turns its 
non-absorbing surface in an advantageous manner towards the section 27 of 
the air conducting conduit 28. 
The longitudinal section 27 of the air conducting conduit 28 (which is 
essentially radially directed towards the enveloping spiral 21 or towards 
the blower wheel 20) opens outside of the zone where the plate-like insert 
body 29 is installed into an air distribution chamber 32. The chamber has 
two distribution ducts 32' and 32" pointing in opposite directions leading 
respectively 2 longitudinal housing walls 3' and 3" as illustrated in FIG. 
3. At the end of each of the air distribution ducts 32' and 32" each 
longitudinal housing wall 3' and 3" is provided with an air passage 
aperture such as the lattice of perforations 33', 33" shown in FIG'S. 2 
and 3. In order that the lattices of perforations 33' and 33" provide a 
relatively large outflow surface, the longitudinal sides of the insert 
body 25 (which contains the enveloping spiral 21 and also the air 
conducting conduit 28) are provided with bevels 35', 35" which procede in 
an acute angle to the adjacent longitudinal housing wall 3', 3". Each are 
provided at least over the longitudinal sections 34' or 34" which display 
the radial part 27 of the air conducting conduit 28. This is best 
illustrated in FIG. 3. In this manner, it is possible to provide the 
longitudinal housing walls 3' and 3" with lattices of perforations 33' and 
33" over a relatively large area. A correspondingly broad distribution of 
the airflow passing through is consequently obtained. Between each 
longitudinal housing wall 3', 3" and the adjacent longitudinal side of the 
insert body 25 which is inclined thereto, a respective swivel flap 36' or 
36" is provided in the box-shaped housing, at least in the area of the 
lattices of perforations 33' and 33". On the one hand, each of these 
swivel flaps 36' and 36" serves as a closure member for blocking the 
passage of air through the lattices of perforations 33' or 33". On the 
other hand, in its open position, each flap becomes active as an air 
conducting member. Each of these swivel flaps 36' and 36" are supported at 
the longitudinal housing walls 3', 3" near the housing rear wall 2 due to 
the fact that the flap engages, by means of a longitudinal rim section 37 
of circular cross-section, with the groove 11 which also has circular 
profile at the inside of the longitudinal housing wall as shown in FIG. 4. 
Each of these swivel flaps 36', 36" may be formed of an extruded profile 
such as of light metal or hard plastics. Each flap displays two faces 38', 
39' or 38", 39" lying at an obtuse angle to one another. This obtuse angle 
is coordinated to the angle between the front face and the inclined 
longitudinal side of the insert body in the air distribution ducts 32', 
32". The construction of these swivel flaps 36' and 36" is clearly 
illustrated in FIG. 3. The two swivel flaps 36', 36" can be adjusted 
independantly of one another between their closure position (shown at that 
the right in FIG. 3), and their open position (shown at the left in FIG. 
3.) This is accomplished by means of a rotory button or toggle 40', 40" 
supported at the housing front wall 5 by a crankpin 41', 41". Each 
crankpin 41' or 42' passes through a circular slot 42' or 42" in the 
housing front wall 5 into a curved crank slot 43' or 43" which is located 
at the free leg 38', 38" of its respective swivel flap 36' or 36", as best 
seen in FIG. 1. The length of the crankpins 41', 41" is chosen so that 
they remain in constant engagement with the curved crank slots 43', 43" 
over the whole range of movement of the swivel flaps 36', 36". 
It is often desirable or necessary to lay out ventilation apparatus for 
rooms in such a way that the air from outside is freed of particles of 
dust or noxious matter before it reaches the interior of the room. This 
can be accomplished in a simple manner through the use of a replacable 
filter insert 44 which is preferably designed and installed as indicated 
by dot-and-dash lines in FIG. 1 and 3. In this embodiment the filter 
insert 44 is located in the section 27 of the air conducting conduit 28 
which is radially directed towards the enveloping spiral 21 in the 
block-like insert body 25. It has a lamellar structure in the form of a 
layered or folded filter material 45 having multiple zig-zags and formed, 
for example, out of paper fleece. The body is fastened along its 
longitudinal edges on to two thin supporting plates 46 and 47, of such a 
material as paper board. The filter insert 44 is enveloped for part of its 
height by a shoulder 48 which is equidistant from the inner boundary wall 
of the air conducting conduit section 27 which is formed in the insert 
body 25, as can be seen in FIG. 1 and 3. For the rest of its height the 
filter insert 44 projects freely into the zone of clearance 30', 30" which 
has been left free between the housing front wall 5 and the surface of the 
insert body 25 which turns towards it. This is clearly shown in FIG. 3. 
The carrier plate 47 of the filter insert 44 is provided with a slot-like 
aperture 49 at which the layered body 45 of filter material is in contact 
with the air conducting conduit 28. It is through this slot-like aperture 
that the entering air encounters the filter surfaces which are formed by 
multiple folding, before the air arrives in the clearance area 30', 30" in 
the interior of the housing 1. The carrier plate 46 of the filter insert 
which is adjacent to the housing front wall 5 is preferably closed over 
its entire extent so that the air can flow from the filter insert only in 
a lateral direction into the interior of the housing one before it reaches 
the air passage openings (that is, the lattices of perforations 33', 33" 
in the longitudinal housing walls 3', 3".) Since the extruded profiles 5' 
and 5", which form the housing front wall 5, are connected in an easily 
removable manner to the longitudinal housing walls 3' and 3", the filter 
insert may be replaced without difficulty when necessary. 
It should be pointed out that a ventilation appliance of the type described 
in detail above may also be laid out as a purely "pressure differential" 
ventilation appliance. For this application, it is sufficient to omit the 
blower wheel 20 and the electric motor 22 from the enveloping spiral 21 of 
the block-construction-type insert body 25. The use of such a pressure 
differential ventilation appliance is especially recommendable for rooms 
in which, on the one hand, a forced ventilation appliance of the type 
described above is being used, but which, on the other hand, because of 
highly efficient sealing action of built-in windows and doors, it is 
impossible to obtain a natural pressure balance. In such cases, in order 
to obtain a pressure balance it is necessary to arrange, in front of the 
forced ventilation appliance, a pressure diffferential appliance which is 
in all other respects identical. This pressure difference ventilation 
appliance is preferably built into a different room wall from that of the 
forced ventilation appliance. Since, in such a pressure differential 
ventilation appliance the holder plate 24 is not required to carry the 
stator 23 of the electric motor 22 and the blower wheel 20, it can be 
advantageous to reverse the relative positions of the plate-like flat 
insert body 29 and that of the holder plate 24 inside the housing 1. Thus, 
in such a pressure differential ventilation appliance the insert body 29 
butts against the insert body 25, while the holder plate 24 is averted 
therefrom. Although it would be conceivable to eliminate totally the 
holder plate 24 made of non-absorbing material, it is found that a better 
sound damping effect is acheived when the holder plate 24 is retained 
(possibly because of the effect it has of weighing down the flat insert 
body 29). 
The installation of the holder plate 24 and the insert body 29 in the 
position for a pressure differential ventilation appliances (which is the 
reverse of the arrangement shown in FIG. 2) presents no difficulties, 
since the installation space required for it in the housing 1 is the same 
and is already available. 
The embodiment of the invention illustrated in the drawing and explained 
above in detail has, among its advantages, not only that it has a simple 
technical assembly and is therefore an especially maintainance-and 
repair-friendly design, but it also has the advantages of a structurally 
small dimensions, which allow a great through-put of air and insures 
thereby a good sound damping. 
Upon actual installation of the ventilation equipment of the present 
invention on the inside wall of a room it has been found that the 
favorable effects of the characteristic design are enhanced upon 
installation. An indication of the enhanced effect is diagrammed in FIG. 
5. When the swivel flaps 36' and 36" are brought into open position as 
shown in FIG. 5, the air is forced into the room through the lattices of 
perforations 33' and 33". The air stream is directed at an obtuse angle 
against the room wall 50 and is laterally deflected by the room wall. In 
part due to the Coanda effect, the air stream 51', 51" lays itself out 
along the wall and tends to flow along the wall. Because of this 
particular flow of fresh air entering the room, a suction effect appears 
in the region in front of the wall 5 of the housing 1 directing the room 
air towards the wall 50 and up to the point of the front edge of the 
lattices of perforations 33' an 33" towards the front wall 5. As the room 
air 52 is drawn in the direction of the wall 50 there is an intense 
turbulent mixing with the entering fresh air 51', 51". Thus, in addition 
to the fact that the fresh air introduced into the interior of the room 
contributes to a substantial improvement in the quality of the room air, 
this phenomenon results in the considerable advantage that the existing 
room air transfers a significant portion of its thermal energy to the 
fresh air. Thus the fresh air which detaches from the room wall 50 will 
have obtained a higher temperature than its entry temperature. Thus, the 
ventilation equipment of the present invention tends to effectively 
eliminate disagreeable draft effects within a ventilated room. 
It is obvious that minor changes may be may be made in the form and 
construction of the invention without departing from the materials' spirit 
thereof. It is not therefore desired to confine the invention to the exact 
form herein shown and described but it is desired to include all such as 
properly come within the scope claimed.