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This
image shows the back side of a grinder. The grinder is enclosed only on three sides
by an incomplete, ventilated doghouse. The back side of the enclosure is missing and
allows silica containing dust to escape the grinding operation.
The back side of this
enclosure should be closed in to knock down dust and provide solid surfaces to improve the
efficacy of the available exhaust ventilation capacity. |
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This
image shows an exhaust intake inside a doghouse enclosure. Exhausting air from the
enclosure in this way is very inefficient in terms of dust capture.
A well designed
doghouse will draw the dust into a slotted plenum at one end of the enclosure and then
into a smooth fishtail duct transition. |
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This
image shows a bag dump hood. The raw duct take-off from the back of the hood (see arrow)
does not support the optimum aerodynamics in the hood and thus compromises the capture
efficiency of the hood.
A baffled or slotted plenum at the back of the hood would be
more efficient. |
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This
image shows a local exhaust hood for a transfer point.
The opening to this hood could
be smaller thus increasing the capture velocity at the face of hood. It could, also, be
equipped with flexible rubber strips to minimize the face opening and maximize capture
efficiency. |
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