Evaporator with internal restriction

Abstract

An evaporator includes a vaporization chamber having a monomer inlet and a vapor outlet. There is a vapor nozzle in the vapor outlet. The evaporator also includes a collar positioned between the vaporization chamber and the vapor nozzle which increases the pressure in the evaporation chamber while the conductance through the nozzle is substantially unchanged.

What is claimed is: 
     
         1 . A flash evaporator comprising:
 a vaporization chamber having a liquid inlet and a vapor outlet;   an atomizer fluidly configured to ultrasonically vaporize a liquid introduced through the liquid inlet;   a vapor nozzle fluidly cooperative with the vapor outlet such that the ultrasonically atomized vapor formed in the vaporization chamber is configured to pass through the vapor nozzle after having passed through the vapor outlet; and   a collar insertable into the vapor outlet and defining:
 an outwardly extending first portion comprising an annular ring with an annular flange; and 
 a non-filtered single opening with a substantially unobstructed vapor flowpath therethrough such that the collar increases a pressure in the vaporization chamber while leaving the conductance of the vapor through the vapor nozzle substantially unchanged to permit the average rate of material accumulation on a substrate placed in fluid communication with the vapor nozzle to remain substantially unchanged. 
   
     
     
         2 . The evaporator of  claim 1 , wherein the collar further comprises a second portion placed adjacent the first portion, the second portion comprising a second annular flange that defines a smaller cross-sectional area than the non-filtered single opening. 
     
     
         3 . The evaporator of  claim 1 , wherein the collar further comprises a second portion placed adjacent the first portion, the second portion comprising a second annular flange that defines a smaller cross-sectional area than the vapor outlet. 
     
     
         4 . The evaporator of  claim 3 , wherein at least one of the flanges extends outward from the collar. 
     
     
         5 . The evaporator of  claim 3 , wherein at least one of the flanges extends inward from the collar. 
     
     
         6 . The evaporator of  claim 3 , wherein at least one of the flanges extends both inward and outward from the collar. 
     
     
         7 . The evaporator of  claim 3 , wherein the first and second portions are permanently connected to one another. 
     
     
         8 . The evaporator of  claim 7 , wherein the first and second portions are welded to one another. 
     
     
         9 . The evaporator of  claim 3 , wherein the first and second portions are removably connected to one another. 
     
     
         10 . The evaporator of  claim 9 , wherein the removable connection is selected from the group consisting of screws, threaded helical surfaces, lugs and grooves, tapered connections, bayonet connections and snap connections. 
     
     
         11 . The evaporator of  claim 1 , wherein the outwardly extending first portion further comprises an inwardly extending portion such that the cross-sectional area defining the non-filtered single opening is reduced. 
     
     
         12 . The evaporator of  claim 11  wherein the inwardly extending portion comprises a flange. 
     
     
         13 . The evaporator of  claim 12 , wherein the inwardly and outwardly extending flanges comprise a single flange. 
     
     
         14 . The evaporator of  claim 3 , wherein the placement of the second portion adjacent the first portion is through connection of the second portion to the annular flange. 
     
     
         15 . The evaporator of  claim 3 , wherein the second portion comprises a second annular flange, and wherein the second annular flange is connected to the annular flange, and wherein the second annular flange has the cross-sectional area less than the cross-sectional area of the vapor nozzle. 
     
     
         16 . An evaporator comprising:
 a vaporization chamber having a liquid inlet and a vapor outlet;   a vapor nozzle fluidly cooperative with the vapor outlet such that a vapor formed in the vaporization chamber is configured to pass through the vapor nozzle after having passed through the vapor outlet; and   a collar positioned between the vaporization chamber and the vapor nozzle, the collar defining a non-filtered single opening with a substantially unobstructed vapor flowpath therethrough such that it increases a pressure in the vaporization chamber while leaving the conductance of the vapor through at least one of the vapor outlet and the vapor nozzle substantially unchanged relative to no such collar being present such that the average rate of material accumulation on a substrate placed in fluid communication with the vapor nozzle is also substantially unchanged.   
     
     
         17 . The evaporator of  claim 16 , wherein the collar comprises an outwardly extending first portion comprising an annular ring and an annular flange. 
     
     
         18 . The evaporator of  claim 17 , wherein the collar further comprises a second portion placed adjacent the first portion, the second portion comprising a second annular flange. 
     
     
         19 . The evaporator of  claim 18 , wherein at least one of the first and second portions extend inwardly. 
     
     
         20 . The evaporator of  claim 17 , wherein the annular flange extends at least one of inwardly and outwardly from the non-filtered single opening.