Method For Coating A Drying Cylinder

Abstract

A method for coating a drying cylinder of a drying apparatus for drying and/or smoothing a fibrous web includes carrying out the coating within the drying apparatus. A system including a coating unit for coating the circumferential surface of a drying cylinder and a drying apparatus, as well as a method for converting or producing a drying apparatus, are also provided.

1 - 16 . (canceled) 
     
     
         17 . A method for coating a drying cylinder of a drying apparatus for at least one of drying or smoothing a fibrous web, the method comprising the following step:
 carrying out the coating step within the drying apparatus.   
     
     
         18 . The method according to  claim 17 , which further comprises:
 supplying a spray additive in a direction of a circumferential surface of the drying cylinder to be coated;   using a beam from a radiation source to melt at least the supplied spray additive and produce a layer; and   carrying out the melting step, in an operating state of the drying apparatus, to cause the beam to impinge along an extension of an application direction of the beam at a point on the circumferential surface located outside a wrap area on the circumferential surface being wrapped with the fibrous web or a clothing carrying the fibrous web.   
     
     
         19 . The method according to  claim 18 , which further comprises using a laser or an electron radiation source to produce the layer. 
     
     
         20 . The method according to  claim 18 , wherein the application direction of the beam extends substantially counter to the direction of gravity. 
     
     
         21 . The method according to  claim 17 , which further comprises applying the coating gradually and layer by layer to provide the coating in a plurality of layers disposed above one another in a radial direction of the drying cylinder. 
     
     
         22 . The method according to  claim 17 , which further comprises applying the coating in at least one layer being:
 an adhesive layer, or   a functional layer, or   at least one adhesive layer and at least one functional layer applied to the at least one adhesive layer in a radial direction, or   a functional layer applied to a circumferential surface of the drying cylinder being free of an adhesive layer lying underneath the functional layer.   
     
     
         23 . The method according to  claim 17 , which further comprises applying the coating in at least one layer produced by using laser cladding or an equivalent method in which a circumferential surface of the drying cylinder to be coated with the at least one layer is partly melted. 
     
     
         24 . The method according to  claim 17 , which further comprises surface-treating a circumferential surface of the drying cylinder at least one of before or after the coating step. 
     
     
         25 . The method according to  claim 24 , which further comprises carrying out the surface-treating step by machining with material removal, grinding or blasting. 
     
     
         26 . The method according to  claim 24 , which further comprises carrying out the surface-treating step before the coating step to remove a possibly already existing coating from the circumferential surface of the drying cylinder. 
     
     
         27 . The method according to  claim 24 , which further comprises carrying out at least one of the coating or surface treatment steps in a non-operating state of the drying apparatus. 
     
     
         28 . A system, comprising:
 a drying apparatus including at least one drying cylinder having a circumferential surface; and   a coating unit for coating said circumferential surface of said drying cylinder, said coating unit including a material supply for a spray additive, an application device for bringing the spray additive to said circumferential surface of said drying cylinder in an application direction, and a radiation source emitting a beam for melting at least the supplied spray additive;   said coating unit being configured to cause the beam for melting at least the spray additive, during an intended operation of said drying apparatus, to impinge at a point on said circumferential surface in an extension of said application direction, said point lying outside a wrap area of said circumferential surface of said drying cylinder being wrapped with a fibrous web or a clothing carrying the fibrous web.   
     
     
         29 . The system according to  claim 28 , wherein said coating unit is configured to determine a main application direction of the spray additive substantially counter to gravity in an installed position for operation of said coating unit. 
     
     
         30 . The system according to  claim 28 , wherein said radiation source is configured to determine an application direction of the beam emitted by said radiation source parallel to or at an angle to a main application direction of the spray additive or to coincide with said main application direction of the spray additive. 
     
     
         31 . The system according to  claim 28 , wherein said radiation source is a laser radiation source, the beam is a laser beam and said laser radiation source is configured for laser cladding. 
     
     
         32 . The system according to  claim 28 , wherein the spray additive fed to said material supply is a strip or a wire or a cord or a powder. 
     
     
         33 . The system according to  claim 28 , wherein said coating unit is nondestructively detachably connectable to said drying apparatus. 
     
     
         34 . A method for converting or producing a drying apparatus including at least one drying cylinder for at least one of drying or smoothing a fibrous web, the method comprising the following steps:
 providing a coating unit for coating a circumferential surface of the drying cylinder, the coating unit including a material supply for a spray additive, an application device for bringing the spray additive to the circumferential surface of the drying cylinder in an application direction, and a radiation source emitting a beam for melting at least the supplied spray additive;   placing the coating unit, in an operating state of the drying apparatus, in an installation position located outside a wrap area of the circumferential surface of the drying cylinder being wrapped with the fibrous web or a clothing carrying the fibrous web; and   using the beam to impinge at a point lying outside the wrap area on the circumferential surface in an extension of the application direction, to melt at least the spray additive during an intended operation of the drying apparatus.   
     
     
         35 . The method according to  claim 34 , which further comprises removing the coating unit following the application of the coating to the circumferential surface of the drying cylinder or after a subsequent surface treatment of the coating by the drying apparatus.