Extractor hoods with no outlet, is it possible?

The lack of an extraction pipe is a frequent problem in the installation of new catering projects or in the adaptation of existing ones without a smoke outlet. “I need a hood for my kitchen and we don’t have an extraction system”, “currently the hood outlet is connected to the bathroom shunt and the neighbors have reported me”; this type of question is very common among commercial kitchen owners.

The solution for this type of room is the installation of a combined system of techniques that help us to filter and purify fumes and odors.

Currently, the best smoke-free hood systems combine different technologies for an optimal final result: Smoke filtration through wet curtain + Electrostatic filtration+Active carbon filtration+Ozone

Is an air hood with no exit to the outside recommended?

When there is no smoke outlet or it is not in good condition, the kitchen hood with no exit to the outside is the best solution.

Mainly, because it avoids the masonry work to open a hole or to reform it, works that are always annoying when dealing with the interior of the house or commercial kitchen and especially in a room as necessary as the kitchen.

With the hoods that work with the recirculation system, a new world of possibilities is opened to you when it comes to installing them in different parts of the kitchen, since it is not necessary to join them to any hole. On the island, on the wall, on the furniture, on the extractor fan on the worktop.

Another great benefit is the cleaning of the active carbon filter of the hood without any smoke outlet. To clean it, it is only necessary to put it in the oven every 4 months at 200ºC. In addition, this type of filter lasts about 10 years in perfect conditions.

Solution for smoke treatment in kitchens without extraction

The treatments to eliminate the smoke of an industrial kitchen, consist of passing the smoke of extraction by several stages of treatment that I detail next:

Extractor hood with water filter (wet filter) integrated in the hood:

This system consists of a water supply (sprayed) to a mixed filter of meshes and slats. When the smoke and grease come into contact with the water, it cools and condenses on the water, which reduces
Electrostatic filtration: It consists of a series of electrostatic action electric filters, based on the capture of particles, by the principle of attraction of these by electric fields of opposite charges. This type of filters are capable of capturing particles of up to 0.01 micron, being the most sophisticated system so far, in the elimination of fatty vapour fumes.

The filter module consists of an electrostatic filter, equipped with an aluminium mesh pre-filter, a synthetic fibre post-filter or an active carbon post-filter.
The air purification obtained from the system is of the composite type and consists of: a first mechanical filtration followed by an electrostatic one and finally a mechanical one (on request).

The pre-filter (mechanical) has the function of treating the coarser particles, such as dust, spores, animal hairs and other particles in suspension, being at the same time a uniform distributor of the air flow to be purified by the electrostatic filter and improving the filtration phase that follows, through the said filter.

The electrostatic filter bases its operation on the principle of electrostatic precipitation: the effect produced by the high voltage applied to the cell that creates an electrostatic field which at the same time positively charges the particles contained in the incoming air, attracting it to a collecting mass plate of different polarity. This filter is highly efficient, up to 95% in air with a relative humidity above 80%.

Elimination and treatment of odors:

This elimination can be done with two systems, independent or joint:

1- Activated carbon box: It consists of making the air that we have previously cleaned of dirt pass between some final filters filled with activated carbon grains, which in the appropriate amount, absorbs the odors. The active carbon filter, whose function is merely deodorant, does not guarantee the total exclusion of odors, even varying its effectiveness and the need for frequent maintenance (change) depending, even, of the food to be cooked and type of cooking (fried, fish, grilled seafood, etc.).

2- Ozone generator: the function of the ozone is to neutralize the chemical and micro-biological contamination of the final air, which cannot be eliminated with other previous processes. It requires a section of about 7 meters of duct for the ozone to be mixed.