Method of collecting soot particles in an electrostatic filter designed for filtration of a gas flow containing electrically charged soot particles

摘要

The gas flow (3) is braked in a collection zone (4) for the soot particles (1) separate from a flow zone (5) where the gas flow flows normally. An electrostatic field is applied to the collection zone and in the flow zone so the electrified soot particles, passing from the normal flow zone to the collection zone, deposit themselves in the collection zone as they come to a stop. The gas flow containing the soot particles flows across an elongated tube (7) with a central part (8) and a peripheral part (9). The process brakes the flow in the particle collection zone by placing an obstacle (10) in its way, in particular made of glass fibre or a metal mesh in the central part. The collection zone has a reduced diameter. To apply an electrical field in the collection zone, a difference in potential is created between a central electrode (12) in the central part and a peripheral electrode (13) in the peripheral part. These electrodes form the walls of the collection zone with almost stationary flow, and the normal flow zone. Depending on the version used, the soot is deposited around the periphery of the electrostatic filter near the peripheral electrode, or in the central part of the filter near the central electrode. The potential difference between the two electrodes is between 5 and 100 kV. An intermediate electrode can also be used between the peripheral and central electrodes, placed near the obstacle. The potential difference between the intermediate electrode and the central electrode and between the intermediate electrode and the peripheral electrode is between 5 and 100 kV. The potential of the intermediate electrode is near that of the mass, to reduce the risk of electrical accidents. The collected soot particles are eliminated by thermal degradation using an electrical resistance, by mechanical means such as a vacuum, or the collection zone is in the form of a removable cartridge, which is extracted and replaced by a new one. An independent claim is also included for an electrostatic filter for carrying out the above process.