Abstract: When cleaning a barrier filter, comprising a plurality of filter elements, of woven fabric of felt, arranged to separate particles out of a polluted gas, the filter elements are cleaned, separately or in groups, by pressurized air pulses, the frequency, the maximum pressure and the duration of which are varied in order to minimize, by an adjustment, the total emission of dust. The frequency and/or the maximum pressure and/or the duration of the cleaning pulses are varied for a group or a plurality of groups of filter elements. After each cleaning pulse, the maximum value for the instantaneous emission of dust, the emission peak, is determined and the emission peak is used, after cleaning a certain group of filter elements, for selecting the frequency and/or the maximum pressure and/or the duration of the cleaning pulses for this group of filter elements during continued operation.

Abstract: An arrangement for cleaning ventilation air coming from a paint spray booth and polluted with paint particles is provided with a liquid flow for separating part of the paint particles from the ventilation air and a wet electrostatic precipitator for separating any remaining paint particles and liquid droplets from the ventilation air. The electrostatic precipitator is located in an enclosure underneath the floor of the spray booth, with a surface of the enclosure being poured over with the liquid flow to remove part of the paint particles. The enclosure is further designed so that the ventilation air from the spray booth is caused to be deflected through an angle of 10.degree.-170.degree. in relation to the substantially vertical direction of flow through the spray booth before passing through the liquid flow and into the electrostatic precipitator.

Abstract: A gas cleansing arrangement comprising a vessel (1) partially filled with liquid (32) and a gas distribution means (14) beneath the liquid surface (34). The gas distribution means (14) comprises obliquely and downwardly extending distribution pipes (26) with upwardly facing inlet openings (64) for contaminated gas and a lower opening (22). The inlet openings are each connected to a venturi device (28) having an outlet opening (31) and suction openings (29) facing the liquid (32). In use, pressurized gas urges an inner liquid surface (46) downwards in the distributor means (14), until the liquid surface (46) reaches and exposes the uppermost inlet opening or openings (64). The gas is then forced through respective venturi device (28) at a pressure drop corresponding to the height difference (h) between the inner liquid surface (46) and respective outlet opening (31).

Abstract: Method for cleansing gas from solid, liquid and/or gaseous contaminants, by bubbling the gas through a liquid bath (32), and by introducing the incoming gas into a distribution means (14) and causing the gas to pass in part-streams through a multiple of inlet orifices (64) located at progressively increasing depths beneath the surface (34) of the liquid (32). With increasing inlet pressure an increasing number of inlet orifices (64) are utilized for an increasing number of part-streams. The gas flow is passed from respective inlet orifices (64) through connecting means (24, 26, 28) to outlet orifices (31) located at a considerably higher height level (h) than corresponding inlet orifices (64). The gas flow is caused to flow out through venturi nozzles (28) and/or to strike against impinger or striking surfaces (39) with a minimum pressure drop corresponding to said height differential (h).