Method and Device for Applying a Material to a Moving Web

Abstract

In a method for applying a substance to a moving web ( 4 ) of a product, an air-vapor mixture is supplied to at least one nozzle ( 13 ) in which the substance is propelled by means of the air-vapor mixture as propellant in an application zone ( 32 ) on the web ( 4 ) is applied. Excess air-vapor mixture and excess material are removed from the application zone ( 32 ). In order to improve the energy efficiency of such a process, it is proposed that at least part of the excess air-steam mixture discharged from the application zone ( 32 ) be recycled and returned to at least one nozzle ( 13 ). In addition, a device ( 1 ) for carrying out the method described above is proposed.

What is claimed is: 
     
         1 - 11 . (canceled) 
     
     
         12 . A method for applying a substance to a moving web, the method comprising:
 supplying an air-vapor mixture to at least one nozzle;   applying the substance through the at least one nozzle to the web in an application zone by the air-vapor mixture acting as a propellant;   discharging excess air-vapor mixture and excess substance from the application zone; and   recycling at least a first portion of the excess air-vapor mixture from the application zone and feeding the first portion of the excess air-vapor mixture back to the at least one nozzle.   
     
     
         13 . The method according to  claim 12 , further comprising:
 dehumidifying the first portion of the air-vapor mixture through a cyclone or a mist eliminator during recycling.   
     
     
         14 . The method according to  claim 12 , further comprising:
 dehumidifying a second portion of the excess air-vapor mixture through the cyclone; and   discharging the second portion of the excess air-vapor mixture downstream of the cyclone into an ambient.   
     
     
         15 . The method according to  claim 14 , further comprising: adding ambient air to the first portion of the excess air vapor mixture after discharging the second portion of the excess air-vapor mixture downstream of the cyclone into an ambient. 
     
     
         16 . The method according to  claim 15 , further comprising:
 transferring heat energy from the second portion of the excess air-vapor mixture to the ambient air added to the first portion of the air vapor mixture downstream of the cyclone.   
     
     
         17 . An apparatus for applying a substance to a moving web, the apparatus comprising:
 a first conduit that feeds an air-vapor mixture to at least one nozzle arranged in an enclosure that envelops an application zone;   a propellant that is formed by the air-vapor mixture and applies the substance to the web in the application zone;   a second conduit that discharges excess air-vapor mixture and excess substance from the application zone;   a third conduit that feeds a first portion of the excess air-vapor mixture into the first conduit.   
     
     
         18 . The apparatus according to  claim 17 , further comprising:
 a fourth conduit through which steam from a vapor source is introduced into the first portion of the excess air-vapor mixture,   wherein the fourth conduit is arranged at the first conduit downstream of a junction of the third conduit and the first conduit.   
     
     
         19 . Apparatus according to  claim 17 ,
 wherein the excess air-vapor mixture is vacuum extracted by a side channel blower from the enclosure that envelops the application zone, and   wherein the side channel blower is arranged downstream of a cyclone that separates water from the excess air-vapor mixture.   
     
     
         20 . The apparatus according to  claim 17 , further comprising:
 a rotary compressor that compresses the first portion of the excess air-vapor mixture and that is arranged in the first conduit upstream of a junction of the first conduit and a sixth conduit.   
     
     
         21 . The apparatus according to  claim 20 , further comprising:
 a mist eliminator that is arranged in the first conduit downstream of a junction of the third conduit and the first conduit; and   a filter that is arranged in the first conduit downstream of the mist eliminator and upstream of the rotary compressor.   
     
     
         22 . The apparatus according to  claim 14 , further comprising:
 a heat exchanger that extracts heat from a second portion of the excess air-vapor mixture, exhausts the second portion of the excess air vapor mixture into an ambient,   wherein the heat exchanger transfers the heat to ambient air that is fed through a fourth conduit and the first conduit to the at least one nozzle.