Deflagration suppression screen for portable cyclonic dust collector/vacuum cleaner

Abstract

A cyclonic portable vacuum cleaner / dust collector has a cyclonic chamber and a filter chamber. The filter chamber contains a filter cartridge with a hollow core positioned over the discharge opening of a motor plate that closes the filter chamber. A vacuum blower is mounted on the motor plate, with an intake tube at the discharge opening of the motor plate. An anti-deflagration screen mounted upon the discharge opening of the cover plate of the filter chamber. The anti-deflagration screen is in the form of a metal mesh creating a multiplicity of small passages to permit exhaust air flow from the filter chamber but blocking any flame front. The screen may be hemispherically domed.

Description

[0001]This is a continuation-in-part of pending application Ser. No. 12 / 607,122, filed Oct. 28, 2009, and of pending application Ser. No. 13 / 029,243, filed Feb. 11, 2011, which claims priority under 35 U.S.C. 119(e) of provisional patent applications Ser. No. 61 / 306,056, filed Feb. 19, 2010 and Ser. No. 61 / 315,695, filed Mar. 19, 2010. The disclosures of these are incorporated by reference herein.BACKGROUND OF THE INVENTION[0002]This invention may be embodied in heavy-duty vacuum cleaners of the type intended for workshop use, such as in wood shops, machine shops, or for industrial applications, namely, a hybrid shop vacuum / dust collector, having a higher capacity (more CFM) than a standard shop vacuum. The invention is more particularly concerned with an improvement in a heavy duty portable vacuum in which there are a two or more dust separation stages, with the large majority of the dust being separated cyclonically and deposited into a drum or barrel, and with the remaining dust ...

AI Technical Summary

Benefits of technology

The solution achieves 95-99% dust separation and filtration, preventing flammable dust re-entry into the ambient air, enhancing industrial hygiene and safety while maintaining efficient operation without the need for frequent filter cleaning or complex flame arresters.

Problems solved by technology

This airborne fine dust can present a health hazard, and in a wood shop environment airborne particulates constitute a serious quality issue as the airborne dust can contaminate varnish or other wood finishes.

The dust that is collected can quickly clog and blind the filter also, which limits air flow and diminishes the efficiency of the vacuum cleaner.

Moreover, filling of the filter material requires that the vacuuming operation be interrupted frequently for cleaning and / or replacing of the filter.

This arrangement exhausts significantly cleaner air back into the ambient, but because the air passes directly from the main collection drum out to the filter housing, the filter accumulates dust quickly and requires frequent cleaning for effective operation.

However, this arrangement requires attaching the cyclone as a separate element in between the shop vacuum cleaner and the dust producing tool or dust pick-up tool.

Such deflagrations may occur in dust collection systems that use filters, (typically pleated cartridge filters) from dust extracted from dust generating tools and processes.

Flammable dust in suspension when ignited can deflagrate or burn quickly, producing flame propagation that radiates out from the source of combustion.

Dust collection systems that experience this type of upset can explode unless adequately protected or vented to atmosphere.

These can be very expensive and complex, requiring gates, dampers, and abort gates that have to be timed electronically and must actuate in small fractions of a second.

Cyclone systems are particularly difficult to adapt to the conventional technique because the flame from a deflagration must be diverted, but at the same time the outlet flow from the system must be simultaneously blocked off, requiring complex and expensive sensors and controls, and also requiring elaborate engineering control equipment.

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