Abrasivejet nozzle and insert therefor

Abstract

An abrasivejet cutting head is disclosed for use in an abrasivejet cutting system. The cutting head includes a replaceable generally cylindrical insert member having a fluid passageway aligned with the passageway of the housing. A waterjet-forming orifice member is supported within the insert in axial alignment with the abrasivejet discharge nozzle located at the downstream end of the cutting head. The insert is locked into the cutting head by the sleeve of an abrasive-carrying conduit, and provides the mixing region in which the abrasive is entrained into the waterjet. By making the jet-forming orifice and mixing region an integral unit, the mixing chamber is conveniently changed every time the wear in the jet-forming orifice requires an orifice change to maintain high cutting efficiency, while adding virtually no cost in additional components since it merely requires a slightly elongated insert than would otherwise be necessary. In addition, the relatively expensive abrasivejet nozzle, which is typically the longest lasting component of the three, need not be replaced until necessary and, when necessary, is easily removed and replaced in co-axial alignment with the orifice. Lastly, the arrangement results in self-alignment of the waterjet-forming orifice, the mixing region and the abrasivejet nozzle.

1 - 4 . (canceled)  
   
   
       5 . An abrasive jet assembly for use in an abrasive jet cutting system of the type including a source of high pressure water and a source of abrasive material comprising: 
 (A) a housing having a body disposed about a first longitudinal axis between an upstream end and a downstream end, a longitudinally extending passageway in communication with said upstream and downstream ends and a conduit-accommodating passageway extending generally radially from the exterior of the housing into a region in the longitudinal passageway, said housing being adaptable to be coupled to a source of high pressure liquid at its upstream end, and to be coupled to an abrasive jet nozzle at its downstream end;    (B) a unitary jet forming insert having 
 (1) an upstream surface and a downstream surface;  
 (2) A longitudinally extending passageway having a longitudinal axis extending between the upstream surface and the downstream surface of the insert and in communication with said surfaces, the second longitudinally extending passageway having an interior surface characterized at the region of its downstream surface for receiving the upstream end of a separable abrasive jet nozzle so that the outer surface of at least a portion of the upstream end of the separable abrasive jet nozzle is flush with at least a portion of the inner surface of the insert in the region of the insert's downstream surface whereby the abrasive jet nozzle is in substantial axial alignment with the longitudinally extending passageway of the insert;  
 (3) A jet-forming orifice in the longitudinal-extending passageway and having a center aligned with the longitudinal axis of the longitudinally-extending passageway of the insert;  
 (4) A radially-extending passageway aligned with the conduit-accommodating passageway of the first housing to place the conduit-accommodating passageway in fluid communication with the longitudinally extending passageway of the insert adjacent a mixing region within the insert, the mixing region located between the jet forming orifice and the downstream surface of the insert, at least a portion of the outer surface of the unitary jet forming insert being flush with at least a portion of the inner surface of the housing for laterally securing the insert within the housing;  
   (C) means for securing the abrasive jet nozzle at the downstream end of the housing so that the longitudinal axis of the nozzle is maintained in substantial axial alignment with the longitudinal extending passageway of the insert.    
   
   
       6 . A method for assembling an abrasive jet assembly for use in an abrasive jet cutting system of the type including a source of high pressure water and a source of abrasive material, comprising the steps of: 
 (A) inserting 
 (1) a unitary jet forming insert having 
 (a) an upstream surface and a downstream surface;  
 (b) a longitudinally extending passageway having a longitudinal axis extending between the upstream surface and the downstream surface of the insert and in communication with said surfaces, the second longitudinally extending passageway having an interior surface characterized at the region of its downstream surface for receiving the upstream end of a separable abrasive jet nozzle so that the outer surface of at least a portion of the upstream end of the separable abrasive jet nozzle is flush with at least a portion of the inner surface of the insert in the region of the insert's downstream surface whereby the abrasive jet nozzle is in substantial axial alignment with the longitudinally extending passageway of the insert;  
 (c) A jet-forming orifice in the longitudinal-extending passageway and having a center aligned with the longitudinal axis of the longitudinally-extending passageway of the insert;  
 (d) A radially-extending passageway into  
 
 (2) a housing having a body disposed about a first longitudinal axis between an upstream end and a downstream end, a longitudinally extending passageway in communication with said upstream and downstream ends and a conduit-accommodating passageway extending generally radially from the exterior of the housing into a region in the longitudinal passageway, said housing being adaptable to be coupled to a source of high pressure liquid at its upstream end, and to be coupled to an abrasive jet nozzle at its downstream end,  
   (B) aligning the conduit-accommodating passageway of the housing with the radially extending passageway of the insert to place the conduit-accommodating passageway in fluid communication with the longitudinally extending passageway of the insert adjacent a mixing region within the insert, the mixing region located between the jet forming orifice and the downstream surface of the insert, at least a portion of the outer surface of the unitary jet forming insert being flush with at least a portion of the inner surface of the housing for laterally securing the insert within the housing;    (C) inserting an abrasive jet nozzle at the downstream end of the housing so that the longitudinal axis of the nozzle is maintained in substantial axial alignment with the longitudinal extending passageway of the insert.    
   
   
       7 . The method of  claim 6  wherein the step of inserting the insert into the housing is performed before the step of securing the abrasive jet nozzle.  
   
   
       8 . The method of  claim 6 , including the step of inserting a conduit into the conduit-accommodating passageway of the housing.  
   
   
       9 . The method of  claim 6  including the step of securing the abrasive jet nozzle so that the longitudinal axis of the nozzle is maintained in substantial axial alignment with the longitudinal extending passageway.  
   
   
       10 . The method of  claim 6  wherein the step of inserting the abrasive jet nozzle is performed so that at least a portion of the outer surface of the nozzle at the upstream end of the nozzle is flush with at least a portion of the inner surface at the downstream end of the longitudinal extending passageway of the insert.