Patent ID: 7571733

Claim:
A method of waterblasting a tube in a tube-and-shell heat exchanger having a plurality of tubes, the ends of which form a flat surface, the method comprising: (a) obtaining a lance comprising a hollow rod having a diameter and a nozzle having a diameter greater than the diameter of the rod; (b) obtaining a safety cage comprising an enclosure with an open bottom and a transparent top, the top having a slot and a means for allowing movement through the slot of the rod but not the nozzle of the lance; (c) passing the lance through the slot in the safety cage such that the nozzle is contained within the cage and the rod extends outwardly through the slot; (d) connecting the lance to a source of high pressure water which flow is regulated by a valve; and (e) placing the cage over a tube with the open bottom of the cage resting against flat surface formed by the ends of the tubes, inserting the lance into the tube, opening the valve, and discharging high pressure water into tube.