The principle of Electrostatic Precipitators The ESP Units are used to clean the airstream of grease and hydrocarbons (smoke) in kitchen exhaust systems. They are highly efficient and can remove particulate down to sub-micron (0.01micro) size. The filter efficiency of 98% is attained during a single pass through the ESP, based on the charging of particles by an ionization section [2] which are then trapped on the earth plates in the collector cell [3]. Larger particulate in the airstream would be removed by the pre-filter [1] and lastly through an afterfilter [4] to prevent any re-entrainment and provide good air distribution.

Filter Technology [1] Pre-filter Eurovent Class 2 [2] Ionization selection [3] Collector section Eurovent Class 9. Filter surface 28.4 meter's sq. [4] Final filter Eurovent Class 2

Odour Neutraliser The O.N.100 is a high tech, simple to install machine designed to neutralize odour laden air in the exhausts ducts of restaurants and industrial plants of all types. Guaranteed patented process!  Simple to fit in any new or existing system.   Very low maintenance expenditure per annum.

How it works

The patented system combines physics and chemistry. A venturi spigot is connected to a duct, this is connected to the ON100 via a nonconductive flexible hose. Ambient air is drawn into the ON100 where it is mixed with the neutralizing chemical to form a vapour or gas, the vapour is then ionized to 15,000V negative and discharged into the duct. The duct is earthed through the electrostatic circuit thus making the contents of the duct at an opposite electrical potential to the ionized chemical. The electrostatic difference forces the chemical to combine physically with the contaminants afterwhich a chemical reaction takes place to neutralize the cooking odour.


Increased Control

There are many degrees of odour control required which depend on the following factors:

Sensitivity of the site
Type and volume of cooking
Layout of the area and proximity to neighbours
Required efficiency

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MIXED MEDIA ELECTROSTATIC FILTER
(For control of gaseous phase contaminants)

It must be appreciated that some molecules can be detected by the olfactory receptor at parts per billion which means that even with the most effective processes of control certain items can still be detected. We combine a number of processes to achieve the best practical control with an eye to physical possibility of applying the control process. Sometimes we employ Activated Carbon or Mixed Media Filters combined with particulate control and the ON100 process.

Odour control filters are not a new concept, however, it is widely known that certain mediums are unable to adsorb particular gases or are inefficient at doing so. There are many volatile gases present in a cooking exhaust which, due to the natural cooling process, are changing state during the path of travel from their release at the cooking process to their ultimate discharge in the atmosphere. Many of these volatile gases can be detected by the human olfactory receptor at levels of parts per billion.

In order to provide a high efficiency odour filter we must provide a medium which is capable of acting as a high quality molecular sieve. It is important that the medium is effective at a high separation efficiency with the broad spectrum of gases present in the kitchen exhaust. In the Mixed Media Filter we use several mediums to adsorb the volatile gases. All of the media is micro porous in structure and it is therefore important that the majority of the particulate phase is eliminated prior to the odour control stage, it is not sufficient to use normal canopy filters as this will result in too much carry over of grease, a high quality filtration process is required combining a number of stages of technology. Various different primary stage particulate filters are manufactured by Purified Air, details available on request.

Set out below are three of the mediums that can be used in the Purified Air Mixed Media Filter System:

Activated Carbon grade 207C

This is one of the highest grade Coconut Carbons which provides a surface area of 1200 square metres per gram. Activated Carbon is well known for odour control finding applications in many processes. Whilst Activated Carbon covers a broad spectrum of gases it has limitations with some of the volatile gases found in a standard cooking exhaust. As previously mentioned some of these volatile gases can be detected by the olfactory receptor at parts per billion it is therefore insufficient to remove these gases at levels of fifty percent or less.

Zeolites

These are crystalline aluminosilicates in which atoms form an extensive three dimensional framework with uniform surface pores and channels. Their shape selective structure allows them to be designed and manufactured to adapt and act as a molecular sieve and a catalyst to specific molecules. Through design the Zeolite can adsorb, at high efficiency, the molecules with which Activated Carbon is inefficient. The available surface area will depend on the design and application, however, for typical cooking a Zeolite bed will have a surface area between 700 - 900 square metres per gram.

Rare Earth's

These components are well known to improve the performance of filters and magnetic devices, they are produced as ultra fine metal powders which are incorporated in minute quantities into both the Activated Carbon and Zeolite beds via ion exchange or impregnation. Mixed Media Filters are highly effective against the gases produced from the cooking process. The filter cartridges are tightly packed and are either made from a loose fill pelletised mix or constructed by bonding the granules together, permanent suspension, using a patented bonding process with conductive material to form an homogenous biscuit. Standard sizes are manufactured to suit repeat applications. Turn key projects can also be accommodated using our known design process and with reference to the specialist manufacturers of the raw material. As far as cooking applications are concerned we have a library of formulae to cover all types of cooking. Most variations allow for increased dwell time combined with different percentage mixes of the raw material.

Ionising of Effects / Electrostatic Enhancement of Filtration Performance

The filters as described above can be enhanced by the use of ionisation. Purified Air Limited are the owners of a filtration enhancement process, protected by world-wide patents. The process provides for sub micron particles and gases to be ionised before entering the filter medium thus imparting a negative charge in the region of 10,000 - 15,000 volts negative. Once charged the components seek to discharge on a positively charged or grounded surface. Our mixed bed filter is constructed from highly conductive materials which are laid on a perforated metal bed in a metal frame. The filter is grounded on the opposite side of the High Tension circuit thus making it positively charged with respect to the negatively charged pollutant. As the negatively charged pollutant is drawn into the positively charged filter the natural adsorption process is magnified by the electrostatic difference thus ensuring a much greater degree of separation. It is known that activated carbon normally has an adsorption capacity of one percent by weight, when used in our process the adsorption capacity is increased to as much as ninety percent by weight. In addition to the increased adsorption capacity the filtration performance is also greatly improved, tests carried out by Etablissement Technique Central De L'Armement - Centre d'Etudes du Bouchet have shown that when tested to the AFNOR NF X 44011 standard our process increased separation efficiency from 0.3 x 10 -2 to 0.3 x 10 -5. A single pass separation efficiency of 99.999997%


To view installation photo's please click here