Duct drafting and Industrial Ventilation
In order for employees to work safely, a well designed industrial ventilation system is a must. There are many poisonous, toxic and dangerous dusts and mists that need to be exhausted.
Dust collection ducting works best when the same high air velocity is maintained throughout the system. Typically, dust collection ductwork is intended to provide for 3500 feet per minute air velocity throughout the entire duct run. As we add collection points along the duct run, the area or size of the duct has to increase to allow the velocity to be maintained. The ductwork system is often "balanced" through the use of sliding "blast gates" at every pick up point in the system.
When flammable or explosize dusts are to be collected, the pick up velocity is increased to 4500 feet per minute and a whole host of safety regulations stipulated by the NFPA come in to play so that the risk of explosion or fire in the duct is minimized. Blast gates are often forbidden in these types of systems due to the risk of combustible material collecting at the blast gate.
If you need information about dust collector design, you might try this dust collector design textbook. A guide to designing, installing, and operating cost-effective filter dust collectors to meet pollution control requirements, for chemical, mechanical, and environmental engineers and plant managers. Covers planning and sizing collectors and accessories, filter selection, feeders and discharge equipment, fans, and electrical controls, with information on specifications
AAA Drafting Services
920 Brant Street, Unit 13
Burlington, Ontario
L7R-1J4
Phone 905-467-0233
Fax 905-681-6055
