WO1991003330A1

WO1991003330A1 - Ejector-type ventilation hood

Info

Publication number: WO1991003330A1
Application number: PCT/SE1990/000563
Authority: WO
Inventors: Anders Krantz
Original assignee: Airchitect I Söderhamn Ab
Priority date: 1989-09-05
Filing date: 1990-09-04
Publication date: 1991-03-21
Also published as: SE8902917A; SE8902917D0; AU6339890A; SE464224B

Abstract

A ventilation hood (4) comprises a top panel (5) and four walls (6, 6', 7, 7') extending downwardly therefrom. The hood is provided with air exhaust means for evacuating e.g. air smelling of cooking from a preparation or cooking installation below, as well as air supply means for introducing supply air into the air exhaust means. The hood (4) is of given standard design, and both the air supply means and the air exhaust means are separate housings (8, 9) of substantially equal length which is but a fraction of the total length of the hood (4). A plurality of housings (8, 9) are mountable in pairs at optional points along the side walls (6, 6') of the hood, an air supply means (8) being positioned opposite to an air exhaust means (9) in each pair to serve different, optionally disposed preparation units (2, 2') forming part of the preparation installation (1) below the hood (4).

Description

EJECTOR-TYPE VENTILATION HOOD

Field of the Invention

The present invention relates to an ejector-type ve tilation hood comprising a downwardly open hood with a to panel and four walls extending downwardly therefrom, nam ly two side walls and two end walls; an air exhaust means associated with one side wall and serving to evacuate fr said hood contaminated air, such as the smell of cooking, water vapour or the like, ascending from a preparation installation, e.g. a cooking installation, located below the mounted hood; and an air supply means associated wit the opposite side wall and serving to blow a flow of sup ply air towards the air exhaust means in order to inter- σept the ascending air and divert it towards the air exhaust means. Description of the Prior Art

Such ejector hoods (see, for instance, EP-A1- 0,000,782) are much used in cooking installations of the kind that occur in, for example, large-scale kitchens, restaurants and the like. In practice, such cooking in¬ stallations differ substantially from one another, both to their dimensions and as to the positions of the dif¬ ferent preparation units used. A simple installation may consist of nothing but a cooker with a set of hot plates for cooking or frying, with a worktop adjacent to the cooker. Other installations may comprise both a cooker a a frying top, while yet other installations are made up e.g. a frying top and a deep-fat fryer. Large installa- tions may consist of a frying top, a cooker, a deep-fat fryer, and an oven. These units, which often have diffe¬ rent dimensions, are sometimes placed next to one anothe Quite frequently, however, they are separated by interme diate worktops, tables, washing-up sinks or the like, which also may be of different dimensions, especially of different widths. The fact that the designs of the cooki installations vary from one kitchen to another has made necessary to specially manufacture the ejector hoods for each kitchen. Quite frequently, the hood has been given the same length and width as the cooking installation below, and has, furthermore, been provided with air supply means and air exhaust means extending along the entire length of the hood side walls. More precisely, the side walls of the hood have been integrated with these means, i.e. the side walls have, together with internal screens, formed these means. In order to obviate the need for expensive and time- consuming specialised manufacture, hoods have been pro¬ duced in modules of uniform design as to length and width. Also these module hoods^'comprise air supply or air exhaust means which once and for all have been fixedly mounted and which extend along the entire length of the hood or the module. When set up, such module hoods are mounted in a desired number above the cooking installation in such man¬ ner that the number of hoods corresponding to a certain length of the cooking installation at issue are mounted in a row in the ceiling above the cooking installation. If, for instance, this installation has a length of eight metres and each module hood has a length of two metres, four hoods are mounted in a row above the cooking instal¬ lation. In ventilation equipment of this type, it is, how- ever, not taken into account that the cooking units, such as cookers, frying tops, ovens, deep-fat fryers or inter¬ mediate worktops or the like, are differently disposed in different cooking installations.

Another inconvenience of prior art ejector hoods is that their air supply means have no kind of filter what¬ soever for cleaning the incoming supply air. Thus, entire¬ ly unpurified air is often taken in from the outside of the building at issue, which may well be located adjacent to traffic routes where exhaust gas is generated. Alter- natively, simple filters are arranged in an inlet conduit which is common to all the ejector hoods and which is located at a distance from the air supply means in the hoods. In both cases, there is a more or less pronounced tendency that solid matter from the incoming contaminate air accumulates on the inside of the inlet conduit and, after some time, is entrained by the on-rushing air and deposited on the cooking installation via the air supply means. Summary of the Invention

The present invention aims at obviating the above inconveniences of prior art ejector hoods and providing hood which not only is inexpensive to manufacture, but also is easily adapted to cooking installations of highl varying designs. Further, the total cost for setting up the hood is ensured to be low. According to the inventio this is achieved in that the hood is of given standard design, and that both the air supply means and the air exhaust means are separate housings also of given standa design, more precisely both housing types are of substan tially equal length which is but a fraction of the total length of the hood, a plurality of housings being mount- able in pairs at optional points along the side walls of said hood, an air supply means being positioned opposite to an air exhaust means in each pair to serve different, optionally disposed preparation units, such as frying tops, cookers, deep-fat fryers or ovens, forming part of the preparation installation below said hood.

In a preferred embodiment of the invention, an exchangeable filter is mounted inside the housing servin as air supply means, the supply air passing through said filter before it is blown out of the housing. Advanta- geously, this filter is accessible from the outside via opening in a front wall of the air supply means, this opening being equipped with a door. Thus, it is ensured that the incoming air is cleaned of solid matter at a point in the space between the air supply means and the air exhaust means, immediately before being blown out. Since it is possible to rapidly and expediently exchange the easily accessible filter, this means that the risk that any solid matter in the supply air drops onto the cooking installation is eliminated. Detailed Description of the Prior Art

EP-A1-0,029,158 discloses an exhaust device which is made up of several separate parts and disposed above a cooking installation. However, this device is no ejector hood with both air supply and air exhaust means, but rather a simple air exhaust means. Brief Description of the Drawings In the drawings,

FIG. 1 is a simplified schematic perspective view illu¬ strating an inventive ejector hood which is set up above a cooking installation, FIG. 2 is a part-sectional longitudinal view illustrating two air supply means forming part of the hood,

FIG. 3 is a simplified cross-sectional view of the hood, and FIG. 4 is an enlarged longitudinal section of an alterna¬ tive embodiment of the air supply means forming part of the hood.

Detailed Description of the Invention

In Fig. 1, a cooking installation generally desig¬ nated 1 comprises a number of separate cooking units, in this case a cooker 2 and a deep-fat fryer 2' , as well as a number of work tops 3, 3'. An ejector-type ventilation hood is generally designated 4. In a manner known per se, this hood is made up of a top panel 5 and four walls extending downwardly therefrom, namely two side walls 6, 6' and two end walls 7, 7¹. The hood is made in one or, optionally, several standard designs. For instance, the hood may have a length of 6,000 mm, a width of 2,000 mm, and a height of 600 mm.

Inside the hood 4 are mounted a number of air supply means 8, 8' , as well as a corresponding number of air exhaust means 9, 9¹, each air exhaust means cooperating with one air supply means. Both means 8 and 9 are sepa¬ rate housings or casings which each are mountable at optional points along the side walls 6 and 6' , respec¬ tively, of the hood. As is apparent from Figs 2 and 3, each air supply means 8 comprises a rear wall 10, a front wall 11, a top 12, a bottom 13, and two end walls 14, 14'. The front wall 11 is formed with a door 15 which can be removed or outwardly pivoted from a position in which it encloses a filter 16 which is mounted in suitable man¬ ner between the two ends walls 14, 14' and can be removed from the housing 8 via the opening that is covered by a door. At the rear portion of the door 15, there is a bent metal sheet 17 which, together with a corresponding por¬ tion of the bottom 13 of the housing, defines an oblique¬ ly upwardly directed gap through which the supply air can be conducted in a so-called intercepting jet which is similarly directed obliquely upwardly towards the asso¬ ciated air exhaust means 9.

Advantageously, the filter 16 is a per se known hol¬ low cylinder which comprises an outer fine-filter layer, a coarse-filter layer inwardly thereof, and one or more batches of strips inside the coarse-filter layer. This filter may be open at its two opposing ends, as is described in SE Patent 8505171-2, or be open at only one end, as is the case in SE Patent 8302657-5. The first filter type is advantageously used when two or more air supply means 8 are interconnected after one another along the associated side wall of the hood, whereas the second filter type is advantageously used when the air supply means are separately mounted without being interconnected In the embodiment of Fig. 2, holes or openings 18 ar formed in each of the two end walls 14, 14' of the air supply means 8, short pipe sockets being optionally asso¬ ciated with these holes. The pipe sockets may be connecte to the end of a branch pipe 19 (see Fig. 2) which in turn is connected to a main pipe 20 for taking in supply air from the outside, e.g. via a central fan which may be com bined with a coarse filter. If the air supply means is connected to another air supply means or a branch pipe, 6 the second inlet opening of the air supply means is kept open. If, on the other hand, the air supply means is mounted individually, without any further connection, the second inlet opening is closed. Like the air supply means, the air exhaust means 9 is a separate housing comprising a rear wall 10' , a front wall 11', a top 12', a bottom 13', and two end walls 14" and 14" ' . In a manner known per se, the front wall of the air exhaust means may be equipped with a grease separator 15' and a vessel or a chute 21 for collecting grease may be arranged below the air exhaust means. Advantageously, the air exhaust means 9 comprises two holes or openings 18' which are formed in the end walls, either for connect¬ ing the exhaust means to an adjacent analogous means, or for connecting it to a branch outlet pipe.

An important feature of the invention is that the air supply means 8 and the air exhaust means 9 are of substan¬ tially the same length, more precisely a length which is but a fraction of the total length of the hood. Most suit- ably, the total length of the hood is a multiple of the length of the separate housings. Thus, the length of the housings 8, 9 may amount to e.g. 750 mm if the total length of the standard hood is 6,000 mm. As mentioned above, the air supply and air exhaust means are arranged to cooperate in pairs in such manner that an air supply means is applied on one side wall of the hood opposite to an air exhaust means on the opposing side wall. Since both means are of equal length, screens 22, 22' can be applied in the same vertical plane between the end walls of two cooperating housings. In practice, these screens may con¬ sist of simple metal sheets of a height substantially equal to that of the housings 8, 9. Together with the housings 8, 9, the screen walls 22, 22' effectively define the space in which the intercepting jet moves from the air supply means towards the grease separator 15' of the air exhaust means 9, the separator serving as suction means. Thus, smells of cooking, water vapour and the like ascend- ing from a cooking unit 2 below are efficiently inter¬ cepted in this space and evacuated via the air exhaust means.

As is best apparent from Fig. 1, guides 23, e.g. in the form of simple rails, may be arranged on the inside o the side walls 6, 6' of the hood. The housings 8, 9 serv¬ ing as air supply means or air exhaust means may be sus¬ pended from these guides and pushed to a desired position along the side walls before being finally fixed in rela- tion to the hood. However, it is also possible to dispens with such guides and instead mount the housings directly on the side walls, e.g. by riveting or screwing.

Fig. 4 illustrates an alternative embodiment of an air supply means, in which the housing only has one con- nection hole 24 which is formed in the top 12 thereof. This air supply means, which advantageously comprises a filter of the type which is open only at one end, is in actual practice only suited for individual mounting with¬ out connection to adjacent air supply means. It should be pointed out, with reference to Fig. 3, that the air supply means 8 suitably comprises a heat insulation 25 ensuring that no condensate forms on the outside of the housing when the comparatively cold supply air enters the housing which is surrounded by relatively warm air from the cooking installation below. Also the embodiment in Fig. 4 is advantageously equipped with such a heat insulation, although this is not shown in the draw ing.

Thus, the inventive ventilation or ejector hood is easily adapted to suit different types of cooking instal¬ lations, since the separate housings cooperating in pairs and having comparatively small dimensions may be mounted exactly at the desired locations above the cooking units generating ascending smells of cooking, water vapour or the like. Further, no expensive air supply or air exhaus 8 means need be arranged above intermediate worktops and the like.

It goes without saying that the invention is by no means restricted to the embodiments described above and shown in the drawings. Thus, the housings serving as air supply and air exhaust means may well have a geometric shape other than the one described. Although the invention has been described in connection with a cooking installa¬ tion, the inventive ventilation hood can also be used with other types of preparation equipment, e.g. worktables in laboratories, comprising not only one or more preparation units from which e.g. water vapour, fumes or the like ascend, but also simple tables or worktops. Furthermore, it should also be observed that the air supply means described above, having a gap-shaped outlet opening from which flows a rather intense jet of supply air, may be combined with one or more intermediate air supply means working at a lower intensity, e.g. by the supply air flow¬ ing out through a grating or, optionally, a disc filter. Such air supply means may advantageously be used in the spaces of the hood that lie between the preparation units 2, 2'. Moreover, it should be pointed out that each air supply means may comprise more than one filter.

Claims

1. An ejector-type ventilation hood comprising a downwardly open hood (4) with a top panel (5) and four walls extending downwardly therefrom, namely two side walls (6, 6') and two end walls (7, 7'); an air exhaust means associated with one side wall and serving to eva¬ cuate from said hood contaminated air, such as the smell of cooking, water vapour or the like, ascending from a preparation installation (1), e.g. a cooking installation located below the mounted hood; and an air supply means associated with the opposite side wall and serving to blo a flow of supply air towards the air exhaust means in order to intercept the ascending contaminated air and divert it towards the air exhaust means, c h a r a c ¬ t e r i s e d in that the hood (4) is of given standard design, and that both the air supply means and the air exhaust means are separate housings (8, 9) also of given standard design, more precisely both housing types are of substantially equal length which is but a fraction of the total length of the hood (4), a plurality of housings being mountable in pairs at optional points along the sid walls (6, 6') of said hood, an air supply means (8) being positioned opposite to an air exhaust means (9) in each pair to serve different, optionally disposed preparation units (2, 2'), such as frying tops, cookers, deep-fat fryers or ovens, forming part of the preparation instal¬ lation (1) below said hood.

2. Ventilation hood as claimed in claim 1, c h a ¬ r a c t e r i s e d in that a separate set of housings comprising at least one pair of air supply and air exhau means (8, 9) is screened off from the remainder of the hood by means of a screen (22) of substantially the same height as the housings, said screen extending between housing end walls (14) opposite one another.

3. Ventilation hood as claimed in claim 1 or 2, c h a r a c t e r i s e d in that at least one exchange¬ able filter (16) is mounted inside the housing (8) serving as air supply means, the supply air passing through said filter before it is blown out of the housing.

4. Ventilation hood as claimed in claim 3, c h a ¬ r a c t e r i s e d in that the filter is a hollow cylin¬ der (16) through which the supply air passes from the inside and out.

5. Ventilation hood as claimed in claim 4, c h a ¬ r a c t e r i s e d in that an inlet (18) for introducing supply air into the filter cylinder (16) opens in an end wall (14) of the housing (8) and is connectible to a branch pipe (19) extending through the hood (4), suitably the top panel (5) thereof.

6. Ventilation hood as claimed in claim 4, c h a ¬ r a c t e r i s e d in that an inlet (24) for introduc¬ ing supply air into the filter cylinder opens in a top (12) of the housing (8) and is connectible to a branch pipe extending through the hood, suitably the top panel thereof.