Method of cleaning an internal access opening by a nozzle with wearing contact

A method for delivering a high velocity working liquid at fluid pressures of about 1,000 to 20,000 pounds per square inch to an internal access opening in a work material for cleaning and for removing thin cross-section materials including burrs from the work material, which comprises:

• (a) providing a high pressure liquid source connected to a nozzle means which comprises a unitary nozzle body shaped to fit into the internal access opening in the work material to remove the thin cross-section materials and having spaced apart ends along a longitudinal axis of the nozzle body with an external sidewall between the ends, wherein one of the ends of the nozzle body has an opening and the other end is closed;
• an internal liquid passageway having a circular cross-section along the longitudinal axis of the nozzle body and extending part of a length of the sidewall from the open end of the nozzle body to an end of the internal liquid passageway adjacent to the closed end of the nozzle body, wherein a diameter of the internal liquid passageway has a constriction between the open and the closed ends that narrows the internal liquid passageway a ratio of at least 2:1 to create the high velocity working liquid from the high pressure working liquid;
• at least one discharge slot means through the sidewall of the nozzle body for emitting the high velocity working liquid onto the work material, wherein the discharge slot means is provided along a plane intersecting the longitudinal axis of the nozzle body and is in liquid communication with the internal liquid passageway, adjacent to the closed end of the nozzle body and leading to the constriction in the internal liquid passageway and wherein the constriction in the internal liquid passageway is in an upstream position with respect to the discharge slot means;
• and a connection means adjacent to the open end of the nozzle body, wherein the nozzle body can be connected to a high pressure working liquid source by the connection means so that the high pressure working liquid can be moved through the internal liquid passageway and exit from the discharge slot means, onto the work material as the high velocity working liquid;
• (b) providing the nozzle means into the internal access opening of the work material wherein the external sidewall comes into wearing contact with the internal access opening without damage to the constriction of the internal liquid passageway and without reducing the effectiveness of the high velocity working liquid;
• and
• (c) pumping a high pressure working liquid through the internal liquid passageway so that the high velocity working liquid exits from the discharge slot means in the internal access opening of the work material to remove the thin cross-section materials.