Method for manufacturing of a metallic sleeve

Abstract

The invention provides a method for preparation of a metallic sleeve surrounding a core comprising the steps of rolling a metallic strip and helically welding the strip forming the sleeve, inserting the core in the sleeve, encompassing the sleeve with a plurality of movable segments and exposing the sleeve to pressure force by pressing the segments against outer surface of the sleeve until a preset dimension of the sleeve is obtained. The method is particularly useful when the core is a monolith encompassed by an intumescent mat, especially when the monolith is a catalysed filter and the mat is made from a fibrous material preferably containing vermiculite. The filter can be installed in a pipe with exhaust from a diesel engine.

1 . Method for preparation of a metallic sleeve surrounding a core, comprising the steps of 
 a. Helically winding a metallic strip and helically welding the strip forming the sleeve;    b. inserting the core in the sleeve;    c. coaxially encompassing the sleeve with a plurality of movable segments; and    d. exposing the sleeve to pressure force by pressing the segments against outer surface of the sleeve until a preset dimension of the sleeve is obtained.    
   
   
       2 . Method according to  claim 1 , wherein the core is a monolith encompassed by an intumescent mat.  
   
   
       3 . Method according to  claim 2 , wherein the monolith is a catalysed filter and the mat is made from a fibrous material.  
   
   
       4 . Method according to  claim 3 , wherein the fibrous material contains vermiculite.  
   
   
       5 . A metallic sleeve with a core prepared according to  claim 1 .  
   
   
       6 . A metallic sleeve with a cylindrical core according to  claim 5 , wherein the length of the sleeve is 100-500 mm preferably 150-350 mm, the outer diameter of the sleeve is 100-450 mm preferably 150-350 mm, wall thickness of the sleeve is 1.0-2.5 mm, preferably 1.25-2.00 mm, and the thickness of the mat is 3-8 mm, preferably 4-6 mm.  
   
   
       7 . A catalysed filter being sleeved with a sleeve in accordance with  claim 1.