Apparatus for removing dust having device for producing air curtain

An apparatus for pneumatically removing dust, comprising:

• a hollow cylindrical main body and integral handle portion having an inlet for receiving high pressure air from a source of high pressure air, the main body having an outlet for the high pressure air at the front end thereof;
• a hollow nozzle element secured to the outlet of the main body for receiving high pressure air therefrom and having
• a hollow conical nozzle cap fitted around the nozzle element and secured thereto, the nozzle cap having an air discharge opening in its front end in communication with said front orifice in said nozzle element and having an annular surface at the rear end thereof having an inner portion which is perpendicualr to the longitudinal axis of said nozzle cap, and at least two contiguous frusto-conical outer portions angling at successively greater angles toward the front of said nozzle cap, the front end of said main body having a surface thereupon parallel to said perpendicular portion of said annular surface to define a small clearance therebetween and extending radially outwardly of said longitudinal axis a distance which is between the inner and outer radial dimensions of the innermost frusto-conical portions of said annular surface, the inner end of said clearance being in communication with said rear orifice,
• whereby high pressure air is forced out of said air discharge opening in said nozzle cap to form a jet of high pressure air and when the high pressure air is simultaneously forced out through said clearance it forms a conical air curtain spreading forwardly from the forward edge of the outermost frusto-conical portion.