EP0879387B1

EP0879387B1 - Extractor hood

Info

Publication number: EP0879387B1
Application number: EP97902724A
Authority: EP
Inventors: Paulus Simon Wilhelmus Jansen
Original assignee: Je Stork Ventilatoren Bv
Current assignee: Je Stork Ventilatoren Bv
Priority date: 1996-02-05
Filing date: 1997-02-05
Publication date: 2002-10-09
Anticipated expiration: 2017-02-05
Also published as: NL1002244C1; WO1997028405A1; AU1674197A; EP0879387A1

Description

The invention related to the field of extractor hoods. Such extractor hoods are used on a large scale in houses or other accommodation having a ventilation system, wherein a fan which is placed centrally and at least at a distance from suction openings through which air, vapour etc. are draught off from a space for ventilating.

In US-A-5,448,987 an extractor hood is disclosed, comprising:

a housing to be fixed to a structure of a building , for instance a wall, at a chosen position by means of fixing means, said housing defining a space;

an outlet to be connected to said space for drawing off air, vapour and the like entering the space via an inlet by means of a fan; and

a plate bounding this space on the underside and having at least a downward convex transition zone near the sides thereof, said plate together with the side walls of the housing defining a number of vents forming said inlet.

It is an object of the present invention to improve upon this known extractor hood, especially in relation to conservation of energy and reduction of acoustic noise. The present invention provides an extractor hood comprising:

a plate bounding this space on the underside and having at least a downward convex transition zone near the sides thereof, said plate, together with the walls of the housing defining a number of vents forming said inlet, characterized by a valve with fixed valve seat and a valve body and which is displacable between an open and a closed position by control means.

The control means are able to control the valve between an open and closed position. The closed position corresponds with a rest position, the fully open position corresponds with a position in which the extractor hood is fully operational, for instance during cooking, while the position with limited passage represents a position with a comparatively low level of extraction.

In a particular embodiment the extractor hood comprises a control button which is coupled to control means which can simultaneously control two functions. The one function relates to switch-on, switch-off or placing in a desired intermediate position of the extractor fan placed at a distance and driven by an electric motor. The other function relates to closing of the said outlet by means of a valve during non-use of the extractor hood. Possible fan noise can thereby be prevented from penetrating into the relevant work area via the outlet opening. When the extractor hood is set into operation the relevant valve can be opened preferably in direct mechanical manner by operating the control button, optionally combined with switch-on or setting of the fan at an increased rotation speed.

The extractor hood preferably has the special feature that at least the components coming into contact with air or vapour for extracting are heat-resistant, fire-resistant and/or flame-extinguishing. A particular development of this principle has the special feature that components consist substantially of polypropylene (PP) filled with talcum. Another embodiment has the special feature that components consist substantially of metal. This latter embodiment can have the feature that the metal is stainless steel.

In order to obtain a very great impact resistance, scratch resistance and form retention, also at relatively high temperatures and the unfavorable climatological conditions in which an extractor hood has to operate, the extractor hood can have the special feature that components consist substantially of a mixture of polycarbonate and ABS. This variant relates particularly to the front of the extractor hood and the control buttons arranged thereon.

The extractor hood preferably has the special feature that the control means are of mechanical type. Such an embodiment can be very inexpensive and reliable.

A preferred embodiment has the feature that the valve body is carried by a resilient support arm and/or formed integrally therewith, this support arm being operated by the control means. The support arm can for instance be a plastic strip. Such a strip is naturally resilient and flexible in transverse direction of its main plane. The control means can for instance comprise a manually operated turning knob which co-acts with the support arm by means of an eccentric cam.

A reliable sealing of the valve in closed position is ensured with an embodiment in which the valve body presses under bias against the valve seat in the closed position of the valve. Particularly by making use of the above described structure with resilient support arm, this variant can be embodied in very simple and reliable manner.

The extractor hood preferably has the feature that the valve seat and the valve have annular co-acting contact surfaces.

This latter embodiment can advantageously have the special feature that the valve seat is placed downstream of the valve body and has a form narrowing in the flow direction. As a result of this form the transmission of sound coming from a remotely placed fan is particularly found to be negligible.

A preferred embodiment in which the valve has a contact surface with the shape of a part of a sphere has the great advantage that this structure is to a large degree independent of the actual position of the spherical contact surface. This allows large manufacturing tolerances while still retaining good operation of the valve.

Test results with a air flow in the range of about 100-200 m³/h, corresponding with practical conditions of use, have demonstrated that the best extraction results are achieved with an embodiment in which the width of each vent amounts to (15 ± 10) mm. A preferred embodiment has the special feature that the width of each vent amounts to (15 ± 5) mm.

The extractor hood is preferably embodied such that all vents have substantially the same width.

An embodiment in which the plate is removable has the advantage that the plate can be cleaned easily and that the interior of the housing, in particular the walls of the hollow space bounded thereby, are easily accessible for cleaning.

A preferred embodiment has the special feature that the control means are adapted to control the valve and the drive of the fan.

It is noted that operation of the lighting means preferably takes place with a separate button.

The invention will now be briefly elucidated with reference to the annexed figures of a random embodiment. In the figures:

figure 1 shows a perspective view from the underside of an extractor hood according to the invention;

figure 2 shows a perspective view of the extractor hood, wherein for the sake of clarity the bottom plate is drawn at a distance;

figure 3 shows a cross section through the bottom plate of figure 2;

figure 4 shows a partly broken away perspective view of the extractor hood;

figure 5 shows a longitudinal section through the extractor hood.

Extractor hood 1 comprises a housing 2 provided with a coating, for instance an enamel layer, and a stainless steel bottom plate 3 which together with side walls 4, 5 and the front wall 6 of the housing bounds the

respective vents

7, 8, 9.

Continuous holes

10, 11, are arranged in bottom plate 3 for passage of light coming from lamps. Arranged on the front side is a central control knob 12 which is rotatable and thus co-acts mechanically via an eccentric transmission 13 (see figure 5) with a convex valve plate 14 which can co-act sealingly in the manner shown in figure 5 with a valve seat 15 which widens in downward direction and which co-acts sealingly with a discharge pipe end part 16. A pushbutton 24 operates the lamps.

As shown in figure 2, the

holes

10, 11 are covered with

transparent windows

22, 23.

Figure 3 shows a possible dimensioning of bottom plate 3. Figure 2 shows this bottom plate 3 in perspective view. It will be apparent from this view that plate 3 has at least partially a substantially prismatic form, i.e. has the same shape in any cross section. At the front and rear however, the plate has downward directed

edges

20 and 21 respectively.

Figure 4 shows schematically with arrows the flow of air drawn in via pipe end part 16. This passes through the three mutually connecting

vents

7, 8, 9, moves through the hollow space 17 in housing 2 and leaves this hollow space via pipe end part 16. Control means and lamps are accommodated in an inner housing 18. Plate 3 is suspended in hooking manner with its rear edge 25 from the rear side of housing 2. At the front side it is fixed to the housing with

screwable fastening bolts

26, 27.

The extractor hood shown in the figures does not comprise a fan. This is arranged at a distance in an outlet conduit coupled to pipe end part 16. The operation of the fan can be stationary, for instance in the case where the fan also serves for ventilation of a house, in which case the extractor hood is included in the extraction circuits or removed therefrom by operating the

valve

14, 15. By means of an electrical switch 28 controllable by knob 12 the remotely placed fan can be switched on and, if desired, be placed in different positions corresponding to different flow rates.

In a preferred embodiment in which this latter principle is implemented, the fan is either switched off or is set to relatively low operation while

valve

14, 15 is closed. In an intermediate position the fan is placed in operative position or in a state of increased excitation and

valve

14, 15 is closed. The fan then draws off the normal quantity of air via circuits other than via the extractor hood.

In the cooking position the fan is in its highest state of excitation and

valve

14, 15 is opened. The fan hereby draws off a relatively large amount of air, a large part of which comes from the extractor hood and a normal quantity of air from other inlet points.

Claims

Extractor hood, comprising:

a housing (1) to be fixed to a structure of a building , for instance a wall, at a chosen position by means of fixing means, said housing defining a space (17) ;

an outlet (16) to be connected to said space (17) for drawing off air, vapour and the like entering the space via an inlet by means of a fan; and

a plate (3) bounding this space on the underside and having at least a downward convex transition zone near the sides thereof, said plate, together with the side walls of the housing defining a number of vents (7, 8, 9) forming said inlet, characterized by a valve with fixed valve seat (19) and a valve body (14) and which is displacable between an open and a closed position by control means.
Extractor hood as claimed in claim 1, wherein the fan is accommodated in the outlet conduit at a distance from the extractor hood.
Extractor hood according to claim 1 or 2, wherein the vents are mutually connected.
Extractor hood as claimed in claim 1, wherein at least the components coming into contact with air or vapour for extracting are heat-resistant, fire-resistant and/or flame-extinguishing.
Extractor hood as claimed in claim 4, wherein components consist substantially of polypropylene (PP) filled with talcum.
Extractor hood as claimed in claim 4, wherein components consist substantially of metal.
Extractor hood as claimed in claim 6, wherein the metal is stainless steel.
Extractor hood as claimed in claim 1, wherein components consist substantially of a mixture of polycarbonate and ABS.
Extractor hood as claimed in claim 1, wherein the control means (13) are of mechanical type.
Extractor hood as claimed in claim 9, wherein the valve body (14) is carried by a resilient support arm (13) and/or formed integrally therewith, this support arm being operated by the control means.
Extractor hood as claimed in claim 1 or 9, wherein the valve body (14) presses under bias against the valve seat (15) in the closed position of the valve.
Extractor hood as claimed in claim 9, wherein the valve seat and the valve have annular co-acting contact surfaces.
Extractor hood as claimed in claim 12, wherein the valve seat is placed downstream of the valve body and has a form narrowing in flow direction.
Extractor hood as claimed in claim 12, wherein the valve has a contact surface with the shape of a part of a sphere.
Extractor hood as claimed in claim 1, wherein the width of each vent (7, 8, 9) amounts to (15 ± 10) mm.
Extractor hood as claimed in claim 15, wherein the width of each vent amounts to (15 ± 5) mm.
Extractor hood as claimed in claim 1, wherein all vents have substantially the same width.
Extractor hood as claimed in claim 1, wherein the plate (3) is removable.
Extractor hood as claimed in claim 1, wherein the control means are adapted to control the valve and the drive of the fan.
Extractor hood as claimed in claim 19, wherein the control means are adapted to hold a valve closed in a determined position and for optionally limited excitation of the fan such that it can be operative for an extraction circuit other than via the extractor hood.