Patent ID: RE38872

Claim:
An excavation system, comprising: a compressed air supply; an air lance including a nozzle including an orifice which forms a means for directing air from said compressed air supply at supersonic velocities towards a material to be excavated; a vacuum engine having an inlet connected to said compressed air supply ; a collection drum; and an adapter fitted on said collection drum, said adapter having a first opening in communication with an opening at the bottom of the vacuum engine and a second opening arranged to receive excavated material, said vacuum engine comprising: a housing having a front wall, two side walls, a rear wall, and a top wall, but which is open at the bottom and is internally divided into first, second, and third chambers, said inlet being situated in said front wall and opening into said first chamber; a first venturi tube connecting said first and second chambers; a second venturi tube connecting said second and third chambers; and a third venturi tube which extends through said rear wall to form a low pressure outlet for said third chamber; a first pressure sensitive check valve positioned in said second chamber between said bottom opening and said second venturi tube; and a second pressure sensitive check valve positioned in said third chamber between said bottom opening and said third venturi tube ; a collection drum; and an adapter fitted on said collection drum, said adapter having a first opening in communication with said opening at the bottom of the vacuum engine and a second opening arranged to receive excavated material .