Dispenser for a jet of liquid bearing particulate abrasive material

Claim 1

In a dispenser for dispensing a jet of liquid bearing particulate abrasive material, comprising in combination: a hollow body defining a bore; liquid inlet means at one end of the bore; outlet means at the other end of the bore for discharging the liquid bearing particulate abrasive material; a mixing chamber disposed between the liquid inlet means and the outlet means; abutment means provided within the bore, between said one end of the bore and the mixing chamber, so as to face said one end of the bore; a nozzle holder seated against the abutment means; a plurality of inlet nozzles mounted in the nozzle holder for directing a flow of liquid through the mixing chamber, each said inlet nozzle being dimensioned and arranged so that, in the use of the dispenser, the radial cross-section of the flow of liquid through the mixing chamber is smaller than the cross-section of the mixing chamber; each said inlet nozzle having a discharge end or tip lying within the mixing chamber at a first axial location relative to the direction of the flow of liquid, and the plurality of inlet nozzles being arranged so as to direct liquid along intersecting axes which are angularly inclined, in the same sense, to radial planes containing the central axis through the mixing chamber; locking means for preventing rotation of the nozzle holder; a supply chamber for the particulate material; passage means for transferring the particulate material from the supply chamber to the mixing chamber, and comprising a plurality of passages which respectively extend along axes convergent with the direction of the flow of the liquid; entry ports in the wall of the mixing chamber by which particulate material leaves the passages and enters the mixing chamber, the entry ports lying at a second axial location relative to the direction of the flow of liquid and axially downstream relative to said first axial location; and said mixing chamber having a portion of axial length as defined between said first and second axial locations wherein the flow of liquid directed by each said inlet nozzle travels within the mixing chamber but wherein no particulate material flows after entering the mixing chamber by way of the entry ports due to said entry ports being at the downstream axial end of said portion.