Cost Effective Dust Collection For The Composite Manufacturing Industry Part 8
PUSH-PULL RE-CIRCULATING
Push-Pull: A method where the air is pulled into the dust collector at one end of a room or enclosure and the filtered air is channeled through ducting to the far end of the room or enclosure where it is then exhausted. This results in a Push Pull effect since the air is being pushed by the clean exhausted air toward the dust collector inlet while it is at the same time being pulled out of the work area and through the filters. This type of system is best suited to large rooms where it is not cost effective to erect smaller enclosures or CCB’s and the room size makes it un-economical to ventilate in its entirety. Let’s use for an example a large room with dimensions of 200 ft. long by 100 ft. wide and a ceiling height of 25 ft. Let’s further state postulate that a conveyer system is moving parts along a route and at various points some activity is taking place that will create some sort of air borne contamination. While the contamination may not be heavy in any one location, if left uncontrolled a dust film would soon form over everything in the building. In this situation the most economically solution might be to try to keep the contamination in the air until such time as it eventually drifts into the capture zone of one the dust collectors space along one wall. The exhausts from these dust collectors is ducted to the far side of the building where the exhaust streams will essentially blow the contaminated air toward the back wall where the dust collectors are located. While this is not a strictly controlled air flow, it would be quite effective and, assuming the total dust load is not too great, it will prove to me much more economical than attempting to move the air across this distance at a velocity that would ensure capture without the push effect.