The present invention relates generally to the control of airborne particulates and, more particularly, to the containment and collection of fugitive dust emissions generated by industrial processing equipment such as rotary crusher/breakers, vibratory screens, and like bulk material sizing and classifying machinery.
Over the past years, much attention has been given to cleaning-up the environment, with particular emphasis being placed on the abatement of air pollution in the industrial segment. Many problems have been encountered in attempting to design and place air pollution control equipment on process equipment which is already in place within a facility. In addition, heavy duty sizing equipment in use in high volume bulk material handling systems, such as rotary crusher/breakers, vibratory screens and the like, are of established, time tested designs which are purchased in an unmodified state and installed in a conventional fashion. Heretofore, in order to control dust emissions generated by such conventional equipment, either as a retrofit of an existing installation or in a new installation, it has been common practice to provide dust collection pick-up stations in the chute work and transfers upstream and downstream of the crusher/breaker or screening equipment. These known dust collection pick-up stations generally comprise ductwork installed in the feed chute of the equipment, take-away chutes and transfers. This extensive ductwork then transports the dust to a remotely located dust collector/air filter installation. A negative draft is induced therein by way of conventional fan means. The collected dust cake is periodically cleaned from the filters and later returned to the product flow. These conventional dust collection systems are quite costly in that they usually require separate building structures and sturdy foundations to support the relatively large dust collection equipment. Voluminous quantities of air are also required to transport the dust laden air to the remotely located collectors. This, in addition to the accompanying duct pressure losses, produces high horsepower fan requirements resulting in high capital and high operating expenses. It is also observed that dust particles generated in this type of operation, such as coal or ore dusts, are highly erosive to the inside diameters of the ductwork and pipes causing noticeable wear in a relatively short time which requires additional expense. Constant maintenance and adjustment are required on the balance systems, rotary valves, dust return conveying systems and interlock controls in these conventional air pollution control installations.
The present invention solves many of the problems heretofore associated with the containment, capture and recovery of fugitive dust generated by rotary crusher/breakers, vibratory screens and the like equipment. The invention provides an integrated dust containment system for such equipment which eliminates the need for ductwork to transport the dust to remote collectors. The dust containment system of the present invention provides for the capture of fugitive dust particles within the confines of the equipment housing and then periodically returns it to the dust generation area within the machine housing. Hence, fugitive dust never leaves the dust generation site. It can be readily appreciated that the present invention requires less air to capture the dust than prior systems. In addition less horsepower is required since there are no duct losses and transport velocity requirements as in prior dust collection arrangements.