The new REVEN® efficiency induction system that works without supply air channels
Conventional kitchen hoods, are capture hoods that suck only. Such kind of hoods are shown in the figure below.
Such kitchen exhaust hoods are installed over the cooking equipment and thereby all cooking fumes rising from the cooking equipment are captured and then sucked away into the exhaust duct. The problem and the technical disadvantage of such conventional exhaust hoods, is the limited efficiency of the extraction. A real 100% sucking performance at such simple kitchen capture hoods, is only given direct at the separators, only directly in this area where these separators are installed, there’s a real powerful suction effect. However, this is very limited and this suction effect is based on the following law:
In the case of a suction pipe with an intake pipe diameter D1, a distance D1 decreases the suction power to only about 7.5%. So for example if we have a suction pipe with a diameter of 20cm and in the suction pipe a suction air flow of 10 meters per second, then this suction power is at a distance of only 20cm to only 7.5% suction power reduced. Contrary to many statements made by other manufacturers, a flow-optimized shape of the inlet nozzle or nozzle plate brings only a small additional positive effect!
This law is also subject to conventional exhaust hoods. These usually have built-in separators in a dimension of a maximum of 50 to 50 centimeters. At a distance of about 30 centimetres to these separators can hardly any suction power be determined, see Fig. From top red red marked semicircle.
Therefore cooking fumes rising from the cooking device are only captured and 100% sucked away immediately, if they are within this distance of 30 centimetres from the separator. If they are located at a greater distance from the separator, they are not captured and can not be sucked away immediately. This leads to the fact that cooking vapours, which are first detected in the hood, “rotate” in the hood and can even leave the exhaust hood again and thus are not caught and sucked away at all!
In order to improve this situation, induction hoods have been used by REVEN so far. These hoods have a supply air connection, through which additional supply air from outside is blown directly into the hood, see the following figure:
This additionally blown supply air from the outside greatly improves the capturing of cooking vapours, as the aerosols, steam and vapours rising from the cooking device, is transported immediately into the suction area of the separator and thus it can not come to the previously described problems of a conventional exhaust hoods. For more details on that, please have a look at the following explainer video:
The disadvantage of such induction hoods, however is the effort that it’s necessary to bring additional supply air from the outside. This supply air is usually air that has to be sucked in from the outside of a building and then it have to be transported to the hood via a suitable supply air duct system, so that it can then be blown into the hood as an induction flow.
This is where the new advanced efficient collection hood of the Rentschler Reven GmbH comes in:
The advanced REVEN® efficiency induction system
The two improvements and optimizations of the advanced efficiency capture hood are:
- There is no supply air from the outside directly injected into the detection hood and
- The room air flowing into the capture hood is sucked in via a special intake and accelerated via an induction flow into the direction of the separators.
In previous kitchen hoods, whether conventional hoods or hoods with induction system, always two types of air flows are detected:
- The so-called thermal flow from the cooking device, means the cooking vapours and aerosols directly from the cooking equipment, see the following figure grey arrows and
- The room air, see the following figure blue arrows. The above-mentioned thermal air flow (gray arrows) always induces additional room air. That means that the thermal flow from the cooking devices when entering into the kitchen hood always induces additional room air (blue arrows), which always flows into the detection device, whether a simple conventional kitchen hood is used, or a modern induction hood is in use.
This illustrated blue arrows in the fig. from above will flow in future in the new developed REVEN® efficiency induction hood, not just simply uncontrolled, with that new system it will be separately sucked and accelerated!
The aspiration of this inflowing room air takes place through separate suction openings at the corners of the new system, at the lower edge, see fig. from above. In that area will in future be the inflowing room air (blue arrows) sucked and accelerated. With fans integrated in the hood, the air sucked in is then blown out through our latest and worldwide patented induction nozzle, with the known positive effects on the thermal airflow (grey arrows). Such a kitchen hood has such an optimised efficiency, but does not require any additional supply air, but nevertheless has the considerably improved capturing, via an induction flow.