Abrasivejet Cutting Head With Enhanced Abrasion-Resistant Cartridge

Abstract

The cutting head of an abrasivejet cutting system preferably includes a replaceable generally tubular cartridge supporting a waterjet-forming orifice-defining member on one side of a mixing region, and an abrasivejet nozzle positioned on the opposite side of the mixing region in axial alignment with said orifice. The cartridge is formed from a material having tensile strength, yield strength and fatigue strength sufficient to withstand the operating pressure of the cutting system and sufficiently malleable and ductile to form a hard seal with a water-inlet tube to which it is coupled. The mixing region is defined within the cartridge by a layer of another material that is more abrasion-resistant than the cartridge material.

We claim: 
     
         1 . An abrasivejet cutting head comprising:
 a cutting head body;   a waterjet-forming orifice member supported within said body and having a waterjet-forming orifice formed around a longitudinally-extending axis;   a generally tubular cartridge extending between relative upstream and downstream ends and positioned within said body to surround the waterjet formed by the orifice member as the waterjet flows towards the downstream end, the cartridge including an insert-accommodating passageway extending from the exterior of the cartridge to its interior; and   an insert sized to fit within the insert-accommodating passageway and having a jet-accommodating through-hole for permitting through-passage of the waterjet towards said downstream end, the insert including an abrasive inlet passage for directing incoming abrasive towards the waterjet for entrainment therewith as the waterjet passes through the insert, the insert being shaped to substantially shield the cartridge from contact with the incoming abrasive.   
     
     
         2 . The cutting head of  claim 1  wherein the waterjet-forming orifice member is supported in the region of the upstream end of the cartridge. 
     
     
         3 . The cutting head of  claim 1  wherein the insert-accommodating passageway extends generally radially from the exterior of the cartridge to its interior. 
     
     
         4 . The cutting head of  claim 3  wherein the insert-accommodating passageway is substantially perpendicular to the longitudinal axis. 
     
     
         5 . The cutting head of  claim 1  wherein the insert-accommodating passageway and the insert have complementary surface features to precisely position the insert within the cartridge in such a way that the jet-accommodating through-hole is substantially aligned with said longitudinal axis. 
     
     
         6 . The cutting head of  claim 5  wherein the insert and the insert-accommodating passageway are substantially prismatic in shape. 
     
     
         7 . The cutting head of  claim 1  wherein the orifice within said orifice member is in diamond. 
     
     
         8 . The cutting head of  claim 7  wherein the cartridge is formed at least in part from stainless steel. 
     
     
         9 . The cutting head of  claim 8  wherein the insert is formed from carbide. 
     
     
         10 . An abrasivejet cutting head comprising:
 a housing having a first longitudinally-extending passageway formed about a longitudinal axis between upstream and downstream ends, said body being adapted to be coupled to a source of high pressure liquid at said upstream end, and to receive an abrasivejet nozzle at said downstream end,   a removable cartridge within the first longitudinally-extending passageway, said cartridge having upstream and downstream faces, a second generally longitudinally-extending passageway in communication with said faces and in substantial axial alignment with the first longitudinally-extending passageway, and a generally radially-extending passage extending from the exterior of the cartridge into the second longitudinally-extending passageway at an interface region, the cartridge having a surface characteristic at the region of its downstream face for receiving the upstream end of a separable abrasivejet nozzle in substantial axial alignment with the second longitudinally-extending passageway;   an orifice member having a waterjet-forming orifice and supported within the cartridge upstream from the interface region with its orifice in substantial axial alignment with the second longitudinally-extending passageway;   an insert extending into the cartridge via the generally radially-extending passage, the insert having a third longitudinally-extending passageway in substantial axial-alignment with the second longitudinally-extending passageway to conduct the formed waterjet through the interface region towards the abrasivejet nozzle, and further having a through-passage oriented to conduct abrasive delivered from a region exterior to the cutting head into the interface region without its conducted abrasive contacting the cartridge.   
     
     
         11 . For use in an abrasivejet cutting system of the type including a waterjet-forming orifice member, a generally tubular cartridge extending between upstream and downstream ends for conducting the waterjet from the orifice member to the downstream end, the cartridge including an insert-accommodating passageway extending from the exterior of the cartridge to its interior; and
 an insert sized to fit within the insert-accommodating and having an abrasive inlet oriented to direct incoming abrasive into the conducted waterjet as it passes through the cartridge while the cartridge is shielded by the insert from contact by the incoming abrasive.   
     
     
         12 . An abrasivejet cutting head including:
 a body;   a waterjet-forming orifice member;   a tubular metal cartridge positioned within the body and having a downstream end region and an upstream end region supporting the waterjet-forming orifice member so that the waterjet is longitudinally directed towards the downstream end region within said cartridge;   a carbide insert extending generally radially into the cartridge and having a jet-accommodating through-hole permitting the waterjet to pass through the insert, the insert further including an abrasive passageway for permitting externally introduced abrasive to interface with the waterjet as the waterjet passes through the insert, the insert being shaped substantially enclose the interface region to shield the cartridge from incoming abrasive.   
     
     
         13 . A replaceable cartridge for use in an abrasivejet cutting system for supporting a waterjet-forming orifice-defining member on one side of a mixing region, and for positioning an abrasivejet nozzle on the opposite side of the mixing region in axial alignment with said orifice,
 the cartridge being formed from a material comprising stainless steel and configured to permit the ingress of abrasive into the mixing region for entrainment with the formed waterjet and to permit the abrasive-entrained waterjet to exit towards the abrasivejet nozzle,   the stainless steel being shielded from contact from the incoming abrasive by an internal layer of carbide material.   
     
     
         14 . A replaceable and generally tubular cartridge for use in the cutting head of an abrasivejet cutting system for supporting a waterjet-forming orifice-defining member on one side of a mixing region, and for positioning an abrasivejet nozzle on the opposite side of the mixing region in axial alignment with said orifice,
 the cartridge being formed from a first material having tensile strength, yield strength and fatigue strength sufficient to withstand the operating pressure of the cutting system and sufficiently malleable and ductile to form a hard seal with a water-inlet tube to which it is coupled, the cartridge being configured to permit the entering of abrasive into the mixing region for entrainment with the formed waterjet,   the mixing region being defined within the cartridge by a layer of a second material that is more abrasion-resistant than the first material and which shields the first material from abrasive entering the cartridge.