External mix spray urethane process and nozzle used therefor

Abstract

A post-mix spray nozzle assembly is provided with a central nozzle forming a first hollow conical spray pattern and a coaxially aligned annular nozzle forming a second hollow conical spray pattern. The first and second hollow conical spray patterns intersect in space remote from the nozzle and form a hollow circular spray pattern.

1 . A post-mix spray nozzle assembly comprising; 
 a central nozzle connected to a first liquid source forming a hollow conical spray pattern and an annular nozzle coaxially oriented relative to the central nozzle and connected to a second liquid source forming a hollow conical spray pattern that intersects and mixes in space, remote from the nozzle, with the hollow spray pattern formed by the central nozzle, thereby enabling two reactive liquids to be sprayed to form a hollow circular spray pattern where the two components are mixed totally external to the nozzle assembly.    
     
     
         2 . The spray nozzle assembly of  claim 1  wherein the mixture of the first and second liquid spray from the nozzle assembly forms a hollow circular pattern which when sprayed on a planar test panel located remotely from and perpendicular to the spray axis forms a hollow circular ring of mixed first and second liquids.  
     
     
         3 . The nozzle assembly of  claim 1  further comprising a nozzle body supporting and coaxially aligning the central nozzle and the annular nozzle.  
     
     
         4 . The nozzle assembly of  claim 3  wherein the nozzle body defines an internal annular reservoir that is interposed in fluid communication between the second liquid source and the annular nozzle.