Gas filter bags cleaned while still in casing - by external liquid sprays in upper zone and internal gas pressure pulses

摘要

The Parent patent describes a method of cleaning gas filter inserts (filter bags) by removing them from the filter casing and spraying them externally with filter jets, while applying gas pressure pulses to the inside. In the patent of addition, the method is carried out with the filter bags still mounted inside the filter casing, where a top plate divides the clean and dirt gas chambers. Pref. in the upper third (or upper quarter) of the dirty or dusty gas chamber, nozzle pipes are equipped with upwardly oriented and downwardly oriented nozzles, so arranged that the upward jets clean the underside of the top plate and the attachment portion of the bags, while the lower jets sweep the upper third of the filter bags. Used in particular for air filtering or gas filtering where the gas contains dyes and pigments of different colours and it is sometimes necessary to remove dust from one process before a different process is used, to prevent contamination by dye of a different colour. With the new arrangement, firstly it is not necessary to remove the filter bags from the filter casing, while secondly it is found that by spraying liquid only onto the upper third or quarter of the filter bags, the pulsating gas pressure inside the bags is sufficient to dislodge the dust from the entire remaining length of the filter bags right to the bottom.