How does an electrostatic precipitator work?
Electrostatic precipitation is an extremely efficient way of filtering fine particles from a flowing gas. Electrostatic precipitators (ESPs) can handle large volumes of air without significantly slowing down the rate of flow, because of the low pressure drop across the electrostatic filter.
Kitchen extraction air is a tricky target, due to the complex mixture of grease, smoke, water vapour and temperature. For this reason, it’s important to use an ESP which has been specifically designed for this harsh environment, rather than a generic industrial electrostatic precipitator.
Electrostatic precipitators start by ionising grease and smoke particles as they travel over ionising electrodes. The particles become electrically charged. Some particles are more susceptible to becoming either positively or negatively charged, which means that the most effective ESPs are those that produce both types of charge and so ionise more particles.
The charged grease and smoke particles travel through the parallel plates of the collector cell and become trapped. The longer the distance the particles have to travel through the collector cells, the more particles are collected.
Voltage is also important. Both ioniser and collector cell voltage should be as high as possible to maximise particle ionisation and capture efficiency.
Once the grease and smoke particles have been removed, the air is free of the characteristic blue fume often seen in emissions from restaurants where the cooking produces high levels of grease and smoke. The collector cells are then removed and cleaned at regular intervals.
Electrostatic precipitators should have a diffuser plate to ensure an even spread of air across the surface of the filter, and pre-filters to collect larger grease particles first.
Where we use electrostatic precipitation
Our Electrostatix ESP uses the best of ESP technology to remove grease and smoke from kitchen extraction air. It creates both positively and negatively charged particles, has particularly deep collector cells for maximum collection, and operates at 12kV and 6kV for the ioniser and collector cell respectively.