Case study "Extractor hood"
Annex 4 - Citation
(54) Extractor hood
(57) The extractor hood comprises a canopy (1) having a suction opening (3), and a chimney (2) which, once assembled for operation, projects upwards from a slot in the canopy and which has a chimney housing having a rack frame (6) comprising frame windows with horizontal base tracks (8) and top tracks (9) and vertical housing-edge tracks (7), between which tracks wall panels (5) are fitted. It is also intended for use in extracting air from the upper space of the kitchen and should have a blower section (14) the housing of which (12) has at least one additional inlet opening (17) and, on its chimney, wall panels which – e.g. for the purpose of replacing filters in this part – are removable, so that the chimney interior is easily accessible. To this end, at least one of the wall panels (5) has a part (63) permeable by an airflow (19) which forms an additional inlet surface and, on the inner side of the chimney or canopy, communicates with the inlet side of the blower (14) for the purpose of circulating air, so that air is extracted through this panel; at least one of these wall panels (5) being removable through being held in two guiding grooves (38, 39) formed on opposite tracks (8, 9) of the frame window with restricted mobility in the panel area between those tracks and pressed by a force (40) into one of those grooves to an insertion depth less than the extent of the wall panel's mobility between the tracks, so that the panels – whether with or without filter – are replaceable. An openable door (73) may be attached to one of the wall panels (5).
 The invention relates to an extractor hood, in particular a kitchen extractor hood, with a canopy having a suction surface and a chimney which, once assembled for operation, projects upwards from a slot in the canopy and which has a chimney housing and is preferably assembled on a rack frame comprising frame windows formed by horizontal base tracks and top tracks and vertical housing-edge tracks, between which tracks wall panels are fitted.
 Standard extractor hoods specially designed for use in kitchens – for extracting or recirculating air – generally have a canopy and a shaft or chimney, such chimneys having three side walls when designed for mounting on a wall and generally four side walls when designed for mounting as an island hood. In the chimney there is a blower section which contains a motor-driven blower in a housing, the latter housing having an inlet-side opening which is connected to the suction opening of the canopy and an outlet-side exhaust opening. Extractor hood chimneys with a frame structure consisting of parallel edge profile rods and transverse struts between which panels are fitted are known (DE-GM 299 16 895). Also known are extractor hoods with chimneys (DE-GM 299 09 279) with glass panels, particularly decorative glass, as walls. However, the chimney structure of the known extractor hoods could be improved, with a view to enhancing air extraction and providing better replacement and maintenance possibilities.
 The invention is intended to improve air extraction and facilitate maintenance and replacement of ornamental parts or parts subject to wear and tear. To achieve this, the chimney contains a blower section containing a motor-driven blower in a housing, the latter having both an opening on the inlet side which is connected to the suction opening of the canopy and at least one additional inlet opening which can optionally be covered by an adjustable mesh, and an exhaust opening on the outlet side, the blower section preferably being placed inside the chimney and the additional inlet opening communicating with the internal free volume of the chimney, the latter having an opening for air communication with the environment in at least one of the chimney-housing walls. In the extractor hood equipped with the internal blower, at least one of the wall panels or the upper side of the chimney or canopy has a part permeable by an airflow which forms an additional inlet surface and, on the inner side of the chimney or canopy, communicates with the inlet side of the blower for the purpose of circulating air. It is desirable that the wall be replaceable, especially as air is also extracted through it. To this end, an openable door is attached to one of the wall panels or at least one wall panel is removable through being held in two guide grooves formed on opposite tracks of the frame window with restricted mobility in the panel area between those tracks and pressed by a force into one of those grooves to an insertion depth less than the extent of the wall panel's mobility between the tracks. This allows, on the one hand, for the extraction of ambient kitchen air above the canopy through filters with a large surface, opening up new possibilities for both extraction and recirculation mode, and, on the other hand, for easy replacement of both these filter plates and any additional plates, for example for cleaning purposes or for changing decorative panels, and facilitates access to the technical equipment installed in the chimney.
 The suction surfaces for extraction of ambient air can be both chimney side walls and, especially in a chimney for wall mounting, the upper side of the chimney, as well as surfaces on the top side of the canopy if it is structured appropriately. If the extractor hood is a recirculation hood, at least one of the air-permeable wall panels is an air-outlet surface, the inside of which communicates for the purposes of conducting air with the outlet side of the blower and can be covered by a replaceable large-surface filter, the outer side of the air-outlet surface preferably having a plate with an air-guide structure which steers filtered purified air in a desired direction. Where ambient kitchen air is extracted through a wall panel, the inlet side of the permeable wall panel is advantageously combined with another large-surface filter, for example a cascade of a dishwasher-proof dirt and grease filter composed of wire mesh and a charcoal-filter plate, adjoining a structure for conducting air to the blower, in particular a funnel known as a "dome" which adjusts the dimensions of the suction surface to the size of the inlet opening on the blower. Between the dome and the blower, there can also be another air-conduction structure such as a cabling or tubing segment.
 The filter plates attached to the wall panels must be regenerated and replaced from time to time. That is why, according to the invention, the chimney of the extractor hood has removable wall panels or an openable door in one of the wall panels. The wall panels can advantageously be taken out by gently lifting them up and swinging them out, at least one of several removable panels having an outwardly projecting handle to facilitate easy lifting against spring force. Where the other panels do not have such a handle, they can be lifted up and swung out after removal of the first panel by gripping on each side or with the aid of a handle fixed to their inner side. The base track of the chimney frame is advantageously an open-top groove forming a guide for insertion of the bottom end of the panel, which can be swung out over this open groove when the panel is pushed upwards against the spring force.
 When fully assembled, the panel can simply be held by its own weight in the guide groove of the base track. However, this may prove a disadvantage during transport, and the panels may also start to shake and rattle. The downward-pushing force is therefore advantageously generated by a spring element fixed to the top track, the vertical movability of the wall panel corresponding in scale approximately to the maximum spring stretch of the spring element.
 This removability of the wall panels or, alternatively, of the openable door in one of the wall panels is advantageous not only for replacing filter plates but also for replacing non-air-permeable wall panels. It also facilitates installation and removal of modules of the technical equipment in the chimney, so that maintenance and repair work can be carried out on the chimney. For example, if the chimney comprises a ventilator housing section containing the blower and a connected motor, this section can be inserted like a drawer into a part of the frame forming the chimney and pushed in or pulled out through the area of the removable wall panel or the door.
 Further details, advantages and modifications of the invention are apparent from the following description of preferred embodiments referring to the drawings, which show:
as Fig. 1, a perspective view of a kitchen extractor hood for extracting cooker and ambient air;
as Fig. 2, a schematic diagram of essential components of an extractor hood of the type shown in Fig. 1 with an open front;
as Fig. 3, a schematic view as in Fig. 2 of a modified embodiment;
as Fig. 4, another schematic view as in Fig. 2 of a modified embodiment;
as Figs 5 to10, schematic horizontal sections of various embodiments of extractor hood chimneys with filter cassettes and wall plates;
 As can be seen in Fig. 1, an extractor hood according to the invention is composed of a canopy 1 and a chimney 2. The canopy has a suction opening 3, namely a large horizontal inlet surface, on its underside and control buttons 4 on the front. The chimney is cuboid in shape with a rectangular or square cross-section and rectangular walls in the form of panels 5, at least some of which are mesh panels. These panels are held in a frame 6 consisting of, as vertical parts, housing-edge tracks 7 and, as horizontal parts, base tracks 8 at the bottom and top tracks 9 at the top. As shown in Fig. 2, the chimney contains in the exhaust passage projecting upwards from the canopy a replaceable grease filter 10 and a replaceable charcoal filter 11, as well as a blower section 14 – also shown separately in Fig 1 – comprising a housing 12 with an inlet-side opening communicating with the suction opening 3, which section is connected by an opening on the outlet side, not visible in the drawing, to an exhaust passage 15 which, in an exhaust hood, eventually leads via an air-conduction installation to a wall sleeve which expels the air from the room. The blower section 14 contains an electric motor and a compressor. In the extractor hood shown in Fig. 1, the foremost panel has a decorative element 16 in the mesh, here in the form of a tendril pattern.
 The cuboid housing 12 is provided on one (Fig. 1) or more sides with, in addition to the downward-facing opening 13, another inlet opening 17, slit into one of its walls, through which the blower extracts air from the interior of the chimney 2 and presses it additionally into the exhaust passage 15. The inlet opening 17 can be formed on one or more of the housing walls, take any form and be equipped with a filter, e.g. a grease filter or suchlike. Particularly for island hoods, it is advantageous to have two inlet openings 17 on facing sides of the housing.
 As indicated by the arrows in Figs 1 and 2, air rising up from the cooker 18 is extracted from the kitchen through the suction opening 3 of the canopy 1, while ambient kitchen air 19 is extracted through the mesh panels 5. The ambient kitchen air 19 is largely composed of air which, although likewise rising from the hobs, flows past the canopy. As Fig. 2 illustrates, the ambient kitchen air 19 passes through the mesh panel 5 and a planar filter cassette 22 arranged behind it, from where it is drawn in by the blower section 14 via the inlet opening 17 and then transported away, together with the exhaust air, through the exhaust passage 15. Fig. 2 shows that, inside the chimney, the airflow 19 extracted via the panel 5 is conveyed through a dome 24 and a tube 25 to the inlet opening 17, where it is steered through a mesh 26, the cross section of the latter's openings being adjustable by a servomotor 27. The large-surface filter cassette 22 allows for very effective air filtering. The latter can be a dust and grease filter or a charcoal filter or a cascade of these two filters.
 Fig. 1 shows only a single inlet opening 17 in the housing 12, but such openings can be located on all sides and/or on top of the housing 12.
 Fig. 3 shows a variation in which the dome 24 is replaced by a wall partitioning off chamber 31 and bearing two additional blowers 33 which controllably transport ambient kitchen air 19 into the exhaust passage 15. The mesh 26, which here, by contrast with Fig. 2, is integrated into the panel, and the additional blowers 33 according to Fig. 3 serve to distribute the extraction capacity between airflows 18 and 19.
 Fig. 4 illustrates yet another modified embodiment in which the blower section 14 is located outside the actual extractor hood, along the length of the exhaust passage 15, for example in the wall sleeve. The air-conducting duct inside the chimney is divided into modules 36 and ambient kitchen air 19 is channelled into one of the modules via the mesh panel 5, the dome 24 and the additional blower 33. In the embodiment shown, the ambient kitchen air 19 is not directed through a filter arranged on the mesh panel 5, but, albeit not shown, there may be filters in the modules 36. Also, the blower section 14 located outside the chimney may have an additional inlet opening analogous to the inlet opening 17 in Fig. 1 to extract ambient air at the level of the blower section.
 Filter cassettes, such as the planar ones illustrated, by way of example, in Figs 2 and 3, must be removable for cleaning and/or for replacement by new filter cassettes. Depending on intensity of use, they may have to be replaced, for example, after a few months. Occasional cleaning is also desirable for air-impermeable wall panels. Figs 5 and 6 show a structure which facilitates the replacement of filters or panels as it enables the wall panels 5 to be removed entirely from and then re-inserted into the frame.
There are various ways of doing this, but Figs 5 and 6 illustrate the possibility of slotting the bottom end of the panel concerned 5, which can be a mesh panel or a plate panel, for example a decorative glass plate, into a lower groove 38 formed in the base track 8 and its top end into an upper groove 39 formed in the top track 9. The upper groove 39 is fitted with a leaf spring 40 which presses down on the panel 5. The groove depth of the upper groove 39 is greater than the groove depth of the lower groove 38, so that by pushing panel 5 upwards against the pressure of the spring 40 with the aid of a handle 41, the bottom end of panel 5 can be lifted out of the lower groove 38, swung out and removed from the frame 6. Any filter cassettes or other filter plates fitted on panel 5 can then be removed and replaced. The panel itself can be cleaned without difficulty. Finally, it is slotted back into the frame 6.
 The handle 41 is designed so that it can also fulfil additional functions, for example as a hanger for cloths and utensils.
 In a simpler embodiment, the leaf spring 40 is superfluous; the panel 5 is then held in the lower groove 38 by its own weight when the extractor hood is assembled for operation.
 Figs 5 to10 illustrate, as examples, various possible ways of structuring the chimney walls of the extractor hood partly with filter cassettes and partly with wall plates, which can, for example, be decorative panels. Fig. 5 shows a wall hood with its chimney open at the back, where it is fixed to the wall of the room. All of the remaining three chimney walls are fitted with filter cassettes. In Fig. 6, only the side walls are fitted with filter cassettes, the front wall being formed by a decorative panel; whereas this decorative panel has been pressed into place and cannot readily be removed, the filter cassettes are snapped into their holders, so that, for replacement, cleaning, etc., they can be easily removed and re-inserted.
 Fig. 7 shows a variation, particularly suitable for an extractor hood to be mounted between furniture, having side wall panels and a filter cassette at the front; Fig. 8 shows, as an example, the option of exhausting filtered air only at one side. Figs 9 and 10 show options for island hoods, i.e. ones not fixed to a wall. In Fig. 9, filter cassettes are inserted on all sides, in Fig. 10, only on two facing sides.
1. Extractor hood with a canopy (1) having a suction opening (3), and a chimney (2) which, once assembled for operation, projects upwards from an aperture in the canopy and which has a chimney housing, and a blower section (14) containing a motor-driven blower in a housing (12), the latter housing having an inlet-side opening (13) which is connected to the suction opening (3) of the canopy (1) and an outlet-side exhaust opening, characterised in that the housing (12) of the blower section (14) has at least one additional inlet opening (17).