FR3138935A1 - Suction hood - Google Patents

Abstract

Title: Suction hood The invention relates to a suction hood for a kitchen installation, comprising: - a suction member; - a body (1) whose interior volume is placed in negative pressure by the suction member and a wall of which is formed by a filtration panel (10) which comprises a rear face (102) directed towards the interior volume of the body (1) and a front face (101) opposite the rear face (10) and through from which air is extracted towards the interior volume of the body (1); - a device for applying liquid to the filtration panel (10); characterized in that the front face (101) of the filtration panel ( 10) is oriented upwards and in that the liquid application device is configured to apply the liquid to the front face (101). Figure for abstract: Fig. 1

Description

Suction hood

This concerns an extractor hood as well as a kitchen installation comprising such a hood. We present in particular a hood for professional use equipped with a liquid duplication system, such as water, preferably comprising a tank and a recycling pump. The invention relates to the field of equipment for suction and filtration of fatty fumes and vapors.

Its application is particularly advantageous in the field of extractor hoods for collective catering and restaurants.

STATE OF THE ART

The catering activity is increasingly equipped with cooking equipment (char ovens, open grills, rotisseries) operating with heavy fuel (charcoal). The significant thermal load produced by this cooking method generates large quantities of smoke, fats and carbon particles at high temperatures.

Consequently, it is obligatory to pay particular attention to cleaning, maintenance and prevention against the risk of fire that these cooking devices can cause.

To try to overcome these constraints, there are currently two types of hoods on the market in which a mist of water is sprayed.

In the two existing cases, the water is sprayed after a first stainless steel filter. An existing model is equipped with spray nozzles operating using pressure from the water supply network. This first process has several major drawbacks:

- the sprayed water is not recovered, and flows directly towards the drain; thus this method generates excessive water consumption which can easily reach 90 m ³ per month for a medium-sized restaurant.

- the spray injectors must be replaced regularly because they become blocked by scale.

- the water mist is partly sucked into the pipes; this causes sealing problems. To recover as much water mist as possible, it is necessary to install drop separators which become clogged and require a lot of maintenance; in addition, the drop separators generate a significant pressure loss on the suction, which requires increasing the power of the extractors leading to increased electrical consumption.

The second existing model is also equipped with spray nozzles positioned behind the filters. However, this operates in a closed circuit. The recovered water is directed to a tank equipped with a filter and a recycling pump.

This process also has several major disadvantages:

- the spray injectors must be replaced even more regularly because they become blocked by scale and by particles of grease and carbon which have not been properly filtered from the recycled water.

- the water mist is partly sucked into the pipes; this causes sealing problems.

- to recover as much water mist as possible, it is necessary to install drop separators. These get dirty and require a lot of maintenance. As in the other model, the drop separators generate a significant pressure loss on the suction, which requires increasing the power of the extractors leading to increased electrical consumption.

- it is necessary to install a bulky tank near the hood and to make the pipe connections between the hood and the tank.

There is a need to provide a hood that overcomes all or part of the disadvantages of current techniques.

SUMMARY

To achieve this objective, according to one embodiment, an extractor hood for a kitchen installation is provided, comprising:
- a suction member;
- a body whose interior volume is placed in depression by the suction member and a wall of which is formed by a filtration panel which comprises a rear face directed towards the interior volume of the body and a front face opposite the rear face and through which air is extracted towards the interior volume of the body;
- a device for applying liquid to the filtration panel;
characterized in that the front face of the filtration panel is oriented upwards and in that the liquid application device is configured to apply the liquid to the front face.

Counterintuitively, the proposed orientation of the front face leads to a “re-entrant” configuration of the filtration panel, with a progressive shrinkage of the internal volume of the body at this level. Thanks to this orientation, the liquid, particularly water-based, can be applied to the front side. The action of the water is more effective, because it is upstream of the hood, which makes it possible to immediately treat the charges present in the air and possible sparks. The air entering the body is therefore already purified, the filtration panel is humidified and regularly cleaned by the liquid and the latter constitutes an element of protection against flames and heat for the entire hood.

According to an advantageous possibility, the hood comprises a liquid reservoir; it can be positioned under the body of the hood, below it; it can be attached to a technical compartment, for example containing a liquid recirculation pump. Both the technical compartment and the tank can be placed immediately below the body; preferably, they do not protrude from this body, in depth and/or width of the hood. The base wall of the body preferably serves as the upper wall of the tank and/or the technical compartment containing the pump.

Another aspect relates to a kitchen installation comprising at least one cooking appliance and a hood as indicated previously. Preferably, the hood is placed above the cooking appliance.

Another aspect relates to an extraction process comprising the application of a liquid to a front face of a filtration panel of a hood.

BRIEF DESCRIPTION OF THE FIGURES

The aims, objects, as well as the characteristics and advantages of the invention will emerge better from the detailed description of an embodiment of the latter which is illustrated by the following accompanying drawings in which:

There represents a sectional view of a hood according to one embodiment.

There represents a perspective view according to this same embodiment.

There shows a perspective view of a filtration panel and a liquid application device.

THE shows a perspective view of a liquid application device.

The drawings are given as examples and are not limiting to the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily on the scale of practical applications.

DETAILED DESCRIPTION

Before beginning a detailed review of embodiments of the invention, the following are set out as optional characteristics which may possibly be used in combination or alternatively:

- the body 1 comprises a base wall 21 in fluid communication with the front face 101 of the filtration panel 10, the hood comprising a liquid reservoir 18 capable of receiving the liquid by gravity flow from the base wall 21;

- the reservoir 18 is located at least partially below and facing the base wall 21;

- a liquid recirculation system is included from the reservoir 18 to the application device;

- the application device comprises a ramp 9 extending transversely relative to the front face 101 and is configured to apply a blade of liquid on the front face 101;

- the ramp 9 is positioned at the level of an upper edge of the front face 101;

- the ramp 9 has a liquid outlet slot whose width is less than or equal to 1mm and/or greater than or equal to 0.3mm;

- the filtration panel 10 is a baffle filter defining corridors directed from top to bottom on the front face 101;

- a gutter 12 projects beyond the lower edge of the front face 101 of the filtration panel 10 and is configured to receive the liquid applied to the front face 101;

- the front face 101 has an acute angle relative to the horizontal greater than or equal to 60° and/or less than or equal to 80°.

There illustrates a cross-sectional view of a hood according to one embodiment of the invention. This hood can equip a kitchen installation and in particular be positioned above an area at which cooking is carried out. It can be an oven, a barbecue, a plancha, or any other cooking appliance. The hood allows fumes to be sucked in. There shows a typical solution in which the hood comprises a fairing extending from a rear zone A, for example at the level of a wall of the kitchen against which the cooking appliance is positioned, to a front zone B which corresponds to the front of the hood. Typically, there is a drop reducing the height dimension of the fairing from the rear zone A to the front zone B so as to form a volume for confining the smoke while freeing up space in height for the personnel involved.

The hood fairing delimits a space for positioning the components allowing the suction of air containing the fumes. In particular, a body 1 forms a space for receiving the air sucked in at the rear of a filtration panel 10 forming an air admission surface in the hood. The suction is produced by any common means to bring the volume of the body 1 into depression, for example with a suction plenum 2 whose mouth is connected to an air exhaust duct advantageously equipped with a fan. 'extraction.

The filtration panel 10 comprises a front face 101 through which the air is admitted and a rear face 102, which is opposite the front face and which is located in the volume of the body 1. It is understood that the filtration panel 10 is configured to filter the air received in the hood, in particular to retain particles such as particles of grease or materials resulting from combustion.

For example, we can implement a filtration panel comprising a peripheral frame visible from the and having juxtaposed plates each presenting filtration elements. On the front face, the plates can be in the form of juxtaposed profiles 103 delimiting longitudinal grooves between them and extending on the front face 101 from top to bottom. The interlocking of the profiles creates a system of baffles allowing particles to be trapped and the entry of air to be slowed down to allow suitable filtration. Such filters are also called shock filters. They are typically made of stainless steel.

Preferably, the filtration panel 10 can be completely or partially removable, for example by removing unit parts of filters along the filtration panel, so as to access the interior volume of the body 1. The reveals this possibility in a perspective view in which a part of filtration panel 10 is shown, but also in which another part is removed so as to access the volume of the body 1. It is understood that this access allows maintenance and cleaning easy.

As is visible in , the filtration panel 10 has an inclination so that the front face 101 is directed upwards. Usually, the inclination of the filtration panel 10 obeys the same arrangement as the fairing, so that the interior volume of the body 1 widens upwards. The configuration adopted here is opposite, in the sense that the filtration panel 10 tends to enter the interior volume of the body 1 upwards. Thus, the depth of body 1 is greater at the bottom than at the top. It is understood that, in this way, water or another liquid can flow on the front face 101 from an area located towards the top of the panel 10 towards the bottom of the panel. This arrangement is, in this sense, completely opposite to the state of the art which provides for spraying on the rear face 102.

The figures represent an example of a liquid application device, at the level of the upper edge of the filtration panel 10. Simply, a liquid consisting of or based on water can be used; it may be water with at least one additive added, for example a disinfectant and/or a degreaser. According to one option, a disinfectant and/or degreasing product is placed, for example in the form of pebbles, in the volume of the body so as to gradually treat the circulating liquid.

Preferably, the liquid application device is configured to produce laminar flow from its mouth. More precisely, as shown in , the liquid outlet can be in the form of a ramp 9 extending transversely to the filtration panel 10 and whose mouth is located near the upper edge of the panel 10. Preferably, the width dimension of the ramp 9 is identical to the width dimension of the filtration panel 10. The liquid outlet slot may have a width (here extending along the height of the panels) less than or equal to 1 mm. This allows good efficiency in producing a laminar flow, that is to say a homogeneous and continuous distribution of the liquid outlet over the entire width of the ramp 9. Depending on one possibility, this width is greater than or equal to 0.3mm. This makes it possible to have a large quantity of liquid flowing through the ramp 9 while remaining in dimensions facilitating maintenance, in particular by reducing, or even eliminating, scaling problems.

Preferably, the liquid application device is configured to produce retention upstream of the outlet slot of the ramp 9. According to one example, to achieve this, a buffer tank 8 equips the ramp 9 and this volume is supplied in water via a tube 7; in the example shown, the tube 7 is then connected to a supply conduit for the buffer volume 8 so as to distribute the liquid entry into the ramp 9. The buffer volume 8 is larger than that of the slot of the ramp 9 so that the liquid is distributed in the buffer volume 8 to supply the ramp over its entire width.

We thus achieve a preferably continuous application over the entire width of the filtration panel 10.

In their illustrated embodiments, the profiles 103 of the filtration panel 10 produce intermediate spaces favoring the flow of the liquid from top to bottom, along the front face 101. Thus, a waterfall fountain effect is produced, with a regular flow watering the front face 101. Thus, preferably, the application of liquid is not a spraying of droplets, but a flow, preferably laminar, along the front face 101. According to one possibility, the flow of the pump may be greater than or equal to 1000l/h per linear meter of boom and/or less than or equal to 2000l/h per linear meter of boom. For example, for a hood with a width of 2 meters, a flow rate of the recycling pump which will make it possible to obtain a homogeneous and regular layer of water is 3200 liters/hour.

For this flow rate, the capacity of the tank is advantageously 60 liters.

In the lower part of the front face 101, the liquid is preferably collected at a base wall 21 of the body 1 of the hood. Preferably, the lower part of the frame of the filtration panel 10 comprises one or more openings 104 through which the liquid can flow towards the interior of the body 1. Preferably, as shown in , a gutter 22 projects outwards at the base of the front face 101 so as to ensure the recovery of the liquid; advantageously, the gutter 22 has an inclined side configured to direct the liquid towards the base wall 21 through the openings 104.

To partition the water, or another liquid, in the volume of the body 1, and in particular to prevent the passage of droplets towards the plenum 2, a separator 3 is placed in the upper part of the panel 10, on the side of its rear face 102 This separator 3 can have the shape of a flap extending over the entire width of the rear face 102. In this way, an upward movement of droplets is prevented; the water impacting this surface condenses and falls on wall 21.

Another aspect of the invention is to propose a compact arrangement to ensure the circulation of the liquid. Preferably, the hood operates in a closed circuit, which involves recovering the liquid which has sprayed the front face 101 of the panel 10 to reinject it at the level of the ramp 9.

For this purpose, the base wall 21 is in fluid communication with a reservoir 18 disposed under this wall, as shown in . Preferably, at least one opening is made in the wall 21 so as to allow the liquid to descend. As shown in the , a filter basket 11 is advantageously arranged at this level to filter the liquid after its action of cleaning the front face 101 of the panel 10.

Preferably, the tank 18 is entirely arranged under the wall 21, that is to say under the body 1 of the hood; this arrangement is particularly compact and avoids the need for a remote tank. Preferably, the reservoir 18 has a depth less than or equal to that of the wall 21 of the body 1.

In the embodiment presented in the figures, a pumping compartment is produced juxtaposed to the tank 18, preferably by exploiting the width dimension of the filtration panel 10. The pumping compartment participates in the recirculation of the liquid. For this purpose, it comprises a suction conduit 6 whose mouth is arranged in an accessible manner from the reservoir 18 so as to pump the liquid from the reservoir 18. The pump 20 is visible at the and ensures the rise of liquid through tube 7, up to the ramp, as described previously.

Advantageously, the pumping compartment also includes an evacuation tube 13 having an outlet into the tank 18 and an evacuation to the outside. In addition, a solenoid valve 12 is advantageously present to vary the liquid circuit configurations. In particular, when the emptying of the tank 18 is desired, the solenoid valve 12 is controlled so as to pump the liquid from the tank 18 through the tube 13.

To monitor the proper functioning of the system and take possible corrective or signaling actions in the event of a fault, we also advantageously provide a sensor 15 detecting a low level for the operation of the pump and/or a low level sensor 16 filling of the tank 18 and/or a sensor 17 for the high filling level of the tank 18.

Also, one option consists of an overflow 14 whose mouth is located projecting from the base wall 21 so that, if the liquid rises on the wall 21 beyond the height of the projection, the overflow full can be evacuated through the distal portion of tube 13.

Preferably, the technical compartment is kept watertight relative to the tank 18 and is regularly ventilated via a ventilation chimney 4.

In use, the liquid is pumped so as to circulate in the tube 7 to supply the ramp 9. The flow of water is regular and in the form of a blade which is applied from the top of the front face 101 of the control panel. filtration 10. Part of the water passes through the filtration panel. Another part descends by gravity over the entire length of the front face 101 and is recovered by the gutter 22 to reach the base wall 21 of the body 1. The water passes through the opening and the filter basket 11 to be then reinjected via the pump via the suction tube 6.

In summary, we propose here a hood in which the position of the filtration panel 10 is reversed compared to what is known until now. The water spray which is usually introduced after the filters and which therefore never humidifies the filters is positioned upstream of the filters.

Advantageously, it is no longer a matter of spraying using injection nozzles, but of a very abundant waterfall flow which is introduced by a fountain-type blade of water from the upper part of the filters. While it was thought until now that spraying was necessary to distribute the water on the surface of the filter and to limit its consumption, the present invention takes an opposite path with abundant watering coupled, preferably, with recirculation of the liquid.

In addition to abundantly humidifying the entire surface of the filters at all times, this high water flow allows the filters to be rinsed and kept clean.

Given that these are no longer injection nozzles sensitive to the phenomenon of blockage by scale or impurities, the water blade having a relatively wide section is not likely to encounter blockage problems.

Furthermore, as opposed to nozzles which spray a very volatile mist of water which must be intercepted using droplet separators so that it is not sucked into the air suction flow, the layer of slightly volatile water diffused from the upper part of the front face of the filters is not or unlikely to be sucked into the conduits, especially since the filter itself constitutes a droplet separator.

The water layer diffused over the entire surface of the filters also allows the fumes to be cooled and suppressed much more effectively than spraying a simple mist of water.

While current techniques apply a completely separate design for the extractor hood and the filtration block, the present invention also has the principle of combining the two materials. To achieve this, the liquid recovery tank also includes a filter and a circulation pump which are directly assembled into the bottom of the hood. With this level of integration, the whole thing is compact and installation is greatly facilitated; in particular, there is no need for a remote tank or complex connection to a water drain.

The invention is not limited to the embodiments previously described and extends to all the embodiments covered by the invention.

NUMERICAL REFERENCES

1. Hood body
2. Suction plenum
3. Droplet separator
4. Ventilation chimney
5. Tank fill line
6. Suction duct
7. Pump outlet tube
8. Buffer volume
9. Ramp
10. Filtration panel
101. Front panel
102. Back side
103. Profiled
104. Opening
11. Filter basket
12. Solenoid valve
13. Drain tube
14. Overflow
15. Low level safety sensor for pump
16. Low liquid fill level sensor
17. High liquid filling level sensor
18. Tank
19. Support
20. Pump
21. Base wall
22. Gutter
A. Rear area
B. Front area

Claims (10)

Suction hood for kitchen installation, comprising:
- a suction member;
- a body (1) whose interior volume is placed under depression by the suction member and a wall of which is formed by a filtration panel (10) which comprises a rear face (102) directed towards the interior volume of the body (1) and a front face (101) opposite the rear face (10) and through which air is extracted towards the interior volume of the body (1);
- a device for applying liquid to the filtration panel (10);
characterized in that the front face (101) of the filtration panel (10) is oriented upwards and in that the liquid application device is configured to apply the liquid to the front face (101). Hood according to the preceding claim, in which the body (1) comprises a base wall (21) in fluid communication with the front face (101) of the filtration panel (10), the hood comprising a reservoir (18) of suitable liquid to receive the liquid by gravity flow from the base wall (21). Hood according to the preceding claim, in which the tank (18) is located at least partially below and facing the base wall (21). Hood according to any one of the two preceding claims, comprising a system for recirculating the liquid from the reservoir (18) to the application device. Hood according to any one of the preceding claims in which the application device comprises a ramp (9) extending transversely relative to the front face (101) is configured to apply a blade of liquid on the front face (101). Hood according to the preceding claim, in which the ramp (9) is positioned at an upper edge of the front face (101). Hood according to any one of the two preceding claims, in which the ramp (9) has a liquid outlet slot whose width is less than or equal to 1 mm and/or greater than or equal to 0.3 mm. Hood according to any one of the preceding claims, in which the filtration panel (10) is a baffle filter defining corridors directed from top to bottom on the front face (101). Hood according to any one of the preceding claims, comprising a gutter (12) projecting beyond the lower edge of the front face (101) of the filtration panel (10) and configured to receive the liquid applied to the front face (101). Hood according to any one of the preceding claims, in which the front face (101) has an acute angle relative to the horizontal greater than or equal to 60° and/or less than or equal to 80°.