Apparatus for improving the collection of gases into a suction orifice

Claim 2

Apparatus for use with a suction orifice which has a source of negative pressure associated therewith and into which air from an air space is exhausted comprising: (a) an air having a wall forming an outlet therefor, said nozzle being connected to a source of positive pressure, said air nozzle being spaced from and directed toward said suction orifice for establishing a first venturi to aid in the directing of air from said space into said orifice; (b) an auxiliary plate extending in substantially parallel, spaced relation to the wall of said air nozzle adjacent the air space affected by the suction orifice; (c) the edge of said auxiliary plate furthermost from said intake orifice being spaced from said intake orifice a distance greater than the corresponding distance between said intake orifice and the outlet of said air nozzle for establishing a second venturi; (d) whereby the capture point of air from said air space is effectively moved further from said orifice and less contaminated gases are allowed to escape.

Claim 3

In combination with an exhaust hood of the type positioned above a work area for collecting contaminated exhaust gases generated in the work area through an intake orifice having a source of negative pressure downstream therefrom, a device for improving the collection comprising: (a) an air nozzle having a wall forming an outlet therefor, said nozzle being connected to a source of positive pressure, said nozzle being spaced from and directed toward said intake orifice for establishing a first venturi to aid in directing contaminated gases toward said intake orifice; (b) an auxiliary plate extending in substantially parallel spaced relation to the wall of said air nozzle with the lower edge of said auxiliary plate being spaced from said intake orifice a distance greater than the distance between said intake orifice and the outlet of said air nozzle for establishing a second venturi below said first venturi; (c) whereby the capture point of said exhaust gases is moved further from said intake orifice thereby improving collection of gases.

Claim 4

In combination with an exhaust hood of the type positioned above a work area for collecting contaminated exhaust gases generated in the work area through an intake orifice having a source of negative pressure downstream therefrom, a device for improving the collection comprising: (a) an air nozzle having a wall forming an outlet therefor, said nozzle being connected to a source of positive pressure, said nozzle being spaced from and directed toward said intake orifice for establishing a first venturi to aid in directing contaminated gases toward said intake orifice; (b) an auxiliary plate extending in substantially parallel spaced relation to the wall of said air nozzle with the lower edge of said auxiliary plate being spaced from said intake orifice a distance greater than the distance between said intake orifice and the outlet of said air nozzle for establishing a second venturi below said first venturi; (c) whereby the capture point of said exhaust gases is moved further from said intake orifice thereby improving collection of gases.