Protected Carbon Steel Pipe for Fire Tube Heat Exchange Devices, Particularly Boilers

Abstract

A protected carbon steel pipe for fire tube heat exchange devices, particularly boilers, comprising internally, at least along a portion of its length, at least one bonded layer of corrosion-resistant material.

1 - 24 . (canceled) 
   
   
       25 . A protected carbon steel pipe for fire tube heat exchange devices, particularly boilers, comprising internally, at least along a portion of the length of the pipe, at least one bonded layer of corrosion-resistant material. 
   
   
       26 . The pipe according to  claim 25 , further comprising internally a single bonded layer of corrosion-resistant material. 
   
   
       27 . The pipe according to  claim 25 , further comprising internally a double bonded layer of corrosion-resistant material. 
   
   
       28 . The pipe according to  claim 25 , further comprising internally a closed coaxial sleeve made of corrosion-resistant material, which is adapted to form an interspace for the flow of the flue gases. 
   
   
       29 . The pipe according to  claim 25 , further comprising internally a closed coaxial sleeve made of corrosion-resistant material, which is adapted to form an interspace for the flow of the flue gases, the outer surface of the sleeve and the surface of the layer that faces it being both smooth. 
   
   
       30 . The pipe according to  claim 25 , further comprising internally a closed coaxial sleeve made of corrosion-resistant material, which is adapted to form an interspace for the flow of the flue gases, ribs being provided which protrude monolithically from the sleeve or the surface of the layer that faces the sleeve and are adapted to make contact with the surface of the layer that faces it or with the surface of the sleeve respectively. 
   
   
       31 . The pipe according to  claim 30 , wherein the ribs have a cross-section shaped like a rounded cusp. 
   
   
       32 . The pipe according to  claim 30 , wherein the ribs have a rectangular cross-section. 
   
   
       33 . The pipe according to  claim 30 , wherein the ribs have a triangular cross-section. 
   
   
       34 . The pipe according to  claim 30 , wherein the ribs have a cross-section which in terms of thickness decreases gradually toward the central region. 
   
   
       35 . The pipe according to  claim 30 , wherein the ribs have a rectangular cross-section with an end face. 
   
   
       36 . The pipe according to  claim 25 , comprising internally a closed coaxial sleeve made of corrosion-resistant material, which is adapted to form an interspace for the flow of the flue gases, ribs being provided which protrude alternately from said sleeve and from the surface of the layer that faces it, the ribs that protrude from the sleeve being adapted to make contact in the presence of a reference with said surface. 
   
   
       37 . The pipe according to  claim 25 , further comprising internally a coaxial sleeve made of corrosion-resistant material, which is provided with variously shaped ribs which are adapted to make contact in the presence of a reference with the surface of the layer that faces the sleeve, said ribs being arranged alternately with respect to variously shaped ribs which protrude from said surface. 
   
   
       38 . The pipe according to  claim 36 , wherein the at least one layer of corrosion-resistant material and the sleeve cover the entire length of the pipe. 
   
   
       39 . The pipe according to  claim 36 , wherein the at least one layer of corrosion-resistant material and the sleeve cover partially the inside of the pipe. 
   
   
       40 . The pipe according to  claim 36 , wherein the at least one layer of corrosion-resistant material and the sleeve cover different lengths inside the pipe. 
   
   
       41 . The pipe according to  claim 25 , comprising internally, at least in one portion of its length, a bonded layer made of corrosion-resistant material which is provided with protrusions which protrude toward an axis of said pipe. 
   
   
       42 . The pipe according to  claim 25 , further comprising internally at least two consecutive modules for conveying the flue gases, each module being delimited by a closed wall made of corrosion-resistant material which comprises a portion bonded to the wall of the pipe and at least one portion which protrudes toward an axis of said pipe. 
   
   
       43 . The pipe according to  claim 25 , further comprising internally two flue gas conveyance modules, each module being delimited by a closed wall made of corrosion-resistant material, which comprises a portion which is bonded to the wall of the pipe substantially along half of a circumferential extension thereof, and a straight portion which protrudes transversely, the straight portions of the wall of the two modules being in mutual contact. 
   
   
       44 . The pipe according to  claim 25 , further comprising internally a plurality of flue gas conveyance modules, each module being delimited by a closed wall made of corrosion-resistant material which comprises a portion bonded to the wall of the pipe and two straight portions which protrude from the ends of said portion bonded to the wall toward an axis of said pipe, the straight portions of the wall of two consecutive modules being in mutual contact. 
   
   
       45 . The pipe according to  claim 25 , further comprising internally a continuous bonded layer of corrosion-resistant material, which is provided with straight protrusions which protrude toward an axis of said pipe. 
   
   
       46 . The pipe according to  claim 25 , wherein the corrosion-resistant material is an aluminum alloy. 
   
   
       47 . The pipe according to  claim 25 , wherein the corrosion-resistant material is stainless steel.