Method for coating an orifice plate

Abstract

A method for coating an orifice plate and an orifice plate having a non-wetting coating thereon is provided. To form the plate, material having non-wetting characteristics can be provided as a surface of a transfer block. The non-wetting material is preferably Teflon (PTFE). The surface of the transfer block comprising non-wetting material can be pressed against the orifice plate, preferably under heating conditions. In one embodiment of the invention, the non-wetting surface is pressed against a spacer plate which is pressed against the orifice plate, preferably under heating conditions. The non-wetting material is vaporized and deposits on the surface of the orifice plate to coat the orifice plate with non-wetting material, but not the inside of the orifice.

What is claimed is:  
     
         1 . A coated orifice plate made by a method comprising the steps of: 
 providing a plate defining at least one orifice defined by orifice walls therein, the plate having a front surface and providing a transfer surface formed of non-wetting material;    positioning the transfer surface adjacent the plate, with a spacer therebetween, the spacer constructed to provide an open space for fluid communication between the transfer surface and the surface of the plate adjacent the orifice;    heating the transfer surface to a temperature effective to vaporize the non-wetting material and permitting the vaporized non-wetting material to coat the surface of the plate adjacent the orifice, the transfer surface spacer and plate constructed and arranged and heated to an effective temperature to coat the surface of the plate adjacent and substantially up to the edge of the orifice, but substantially not the surface of the orifice walls.    
     
     
         2 . The coated orifice plate of  claim 1 , wherein the non-wetting material comprises PTFE.  
     
     
         3 . The coated orifice plate of  claim 1 , wherein the plate includes orifices at a spacing of 72-140 orifices per inch.  
     
     
         4 . The coated orifice plate of  claim 1 , wherein the plate includes at least one cluster of approximately seven orifices formed in a hexagon with a seventh orifice in the center thereof.  
     
     
         5 . The coated orifice plate of  claim 1 , wherein the plate includes a range of approximately twenty to forty of the groups of approximately seven orifices.