Sheet stabilizer with suction nozzle having center protrusion

Abstract

This invention is related to suction nozzles having a center protrusion for stabilizing a continuous web for various web property measurements. Suction nozzles blow air out of the nozzle, yet produce a vacuum proximate thereto. Two nozzles are disclosed, a single sided sheet-contact stabilizer and a non-contact sheet stabilizer. An air-bearing may be formed between the end surface of the center protrusion and the moving web.

What is claimed is: 
     
         1 . A web stabilizer for stabilizing a moving web, the stabilizer comprising:
 a nozzle body including a first surface facing the web;   a protrusion including a second surface facing the web, said second surface being offset from said first surface and including at least one orifice;   an air chamber located within said nozzle body and including at least one air inlet port that directs compressed air into said air chamber;   an annular opening formed between said protrusion and said first surface and in fluid communication with said air chamber;   an insert including an insert chamber that is in fluid communication with said at least one orifice and receiving pressurized air therein; and   wherein compressed air evacuates said air chamber through said annular opening and wherein compressed air evacuates said insert chamber through said at least one orifice.   
     
     
         2 . The stabilizer according to  claim 1  wherein said at least one air inlet port is configured to cause a vortex flow pattern within said air chamber 
     
     
         3 . The stabilizer according to  claim 1  wherein said at least one orifice comprises a plurality of orifices. 
     
     
         4 . The web stabilizer according to  claim 1  wherein said first surface is substantially parallel to said second surface. 
     
     
         5 . The web stabilizer according to  claim 2  wherein said air chamber includes a first cylindrical section, a second cylindrical section and a frusto-conical section, second cylindrical section having a smaller diameter than said first cylindrical section. 
     
     
         6 . The web stabilizer according to  claim 5  wherein said at least one air inlet port is positioned at said first cylindrical section, said frusto-conical section joining said first cylindrical section and said second cylindrical section, and said second cylindrical section being proximate to said annular opening. 
     
     
         7 . The web stabilizer according to  claim 1  wherein said protrusion includes a chamfer extending circumferentially around said second surface.