Patent ID: 7128216
Filing Date: 2006-10-31
Classification: B07B

Abstract:
1. An apparatus for sorting wood chips, containing chips in a variety of sizes and/or fines particles, in a wood chips processing chamber, in separate fractions by means of an air flow, which is delivered from one or more nozzle chambers by way of a nozzle slit into the wood chips processing chamber and which applies an impulse action to the wood chips as the wood chips slide along an inclined support surface to sort the chips into said separate fractions within the processing chamber, said air being circulated from the wood chips processing chamber by way of a dedusting cyclone into said one or more nozzle chambers, the improvement comprising: a closed air circulation system in which air flow from the wood chips processing chamber to the dedusting cyclone is controlled by an exhaust fan and air flow from the nozzle chamber into the processing chamber is controlled by a nozzle fan downstream of the exhaust fan; a pipe arranged between the exhaust fan and the nozzle fan extending from the dedusting cyclone to the nozzle chamber, wherein said pipe is in direct communication with an ambient atmosphere; and a negative pressure in the wood chips processing chamber is maintained at a predetermined level in dependency on said exhaust fan to regulate the amount of air removed from the wood chips processing chamber into the dedusting cyclone.