Air sampling apparatus

Claim 2

In air sampling apparatus having, a housing, a roof fixed over said housing and spaced above said housing to permit air to flow into said housing between said roof and said housing, a filter located below said roof, means for drawing air through said filter, a cover plate, means mounting said cover plate with respect to said filter for movement into and out of positions covering said filter, and means for moving said cover plate to a covering position when no air is to be drawn through said filter and uncovered position when air is to be drawn through said filter.

Claim 3

In air sampling apparatus comprising, a rectangular housing open at its upper end, a roof hinged to said one side of said housing and adapted to cover said upper end while permitting air to flow into said housing between the upper end and said roof, a support plate mounted in said upper end and having an opening therethrough, a filter receptacle in said opening, a filter in said receptacle, a blower and motor mounted below said filter to draw air through said filter, the improvement comprising, a cover plate movable between a first position overlying said filter receptacle and a second position lying vertically along one side of said housing, and means including a control circuit for moving said cover plate to said first position when said blower motor is inoperative and said second position when said blower motor is operating.

Claim 4

In air sampling apparatus comprising, a rectangular housing open at its upper end, a roof hinged to said one side of said housing and adapted to cover said upper end while permitting air to flow into said housing between the upper end and said roof, a support plate mounted in said upper end and having an opening therethrough, a filter receptacle in said opening, a filter in said receptacle, a blower and motor mounted below said filter to draw air through said filter, the improvement comprising, a cover plate movable between a first position overlying said filter receptacle and a second position lying vertically along one side of said housing, and means including a control circuit for moving said cover plate to said first position when said blower motor is inoperative and said second position when said blower motor is operating.

Claim 5

Air sampling apparatus as in claim 2 in which said moving means comprises, a vertical screw, reversible means for rotating said screw, a nut and nut plate threaded onto said screw for vertical movement when said screw rotates, said cover plate hinged to said nut plate to swing to said first position when said nut plate rises to the upper portion of said screw and to said second position when said nut plate is lowered to the lower portion of said screw.

Claim 6

Air sampling apparatus as in claim 3, said roof being gabled and presenting an inclined surface immediately above said cover plate in its second position and engageable by said cover plate as it moves from said second position to said first position whereby said inclined surface is adapted to cam said cover plate from a vertical plane in said second position to a horizontal plane in said first position.

Claim 7

Air sampling apparatus as in claim 3 further comprising a pair of posts mounted on said nut plate and engageable with the walls of said rectangular housing to resist twisting of said nut plate.

Claim 8

Air sampling apparatus comprising, a main housing having an open upper end, a roof fixed over said housing and spaced above said housing to permit air to flow into said housing between the roof and said housing, a horizontal support at the upper end of said housing below said roof, a horizontal aperture plate resting on said support and having a central hole therethrough, a filter and blower assembly mounted on said aperture plate, a vertical control housing mounted on said aperture plate and depending therefrom into said main housing, a filter cover positioned adjacent to said control housing, filter cover moving means in said control housing and connected to said cover, control means in said housing connected to said filter cover for moving said filter cover moving means between a position covering said filter and a position uncovering said filter.

Claim 9

Air sampling apparatus comprising, a main housing having an open upper end, a roof fixed over said housing and spaced above said housing to permit air to flow into said housing between the roof and said housing, a horizontal support at the upper end of said housing below said roof, a horizontal aperture plate resting on said support and having a central hole therethrough, a filter and blower assembly mounted on said aperture plate, a vertical control housing mounted on said aperture plate and depending therefrom into said main housing, a filter cover positioned adjacent to said control housing, filter cover moving means in said control housing and connected to said cover, control means in said housing connected to said filter cover for moving said filter cover moving means between a position covering said filter and a position uncovering said filter.