Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F1/00—Tubular elements; Assemblies of tubular elements
  • F28F1/02—Tubular elements of cross-section which is non-circular
  • F28F1/022—Tubular elements of cross-section which is non-circular with multiple channels
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F1/00—Tubular elements; Assemblies of tubular elements
  • F28F1/003—Multiple wall conduits, e.g. for leak detection
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F1/00—Tubular elements; Assemblies of tubular elements
  • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
  • F28F1/40—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only inside the tubular element
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
  • F28F13/06—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
  • F28F19/02—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings
  • F28F19/06—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings of metal
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F2215/00—Fins
  • F28F2215/10—Secondary fins, e.g. projections or recesses on main fins

Definitions

• the present invention relates to a protected carbon steel pipe for fire tube heat exchange devices, particularly boilers.
• fire tube heat exchange devices which provide pipes designed to convey flue gases generated by combustion in appropriate furnaces, such pipes being provided within a vessel which contains the fluid to be heated; among such devices, boilers for generating hot water or another heat transfer fluid are particularly important.
• the pipes comprised within said devices are made of carbon steel in order to ensure optimum quality of the welded joints between the pipes and the structures of the devices, which are also made of carbon steel; however, in the case of devices, such as for example condensing boilers, in which the water vapor contained in the flue gases condenses inside the flue gas conveyance pipes, condensation forms which attacks strongly by corrosion the wall of the pipes.
• Pipes of the described type are not typical only of boilers, but can be present also in other devices of industrial thermal cycles, such as for example condensers, economizers and heat exchangers. Disclosure of the Invention
• the aim of the present invention is to provide a carbon steel pipe adapted to convey flue gases which is entirely protected against the danger of corrosion caused by condensation and further ensures high efficiency in the transmission of heat from the flue gases to the fluid, and in particular to the water, to be heated.
• Figure 1 is a longitudinal sectional view of a fire tube boiler with a pipe according to the present invention
• Figure 2 is a partial sectional view, taken along the line II-II of Figure l ;
• FIG. 3 to 25 show the same sectional view according to variations. Ways of carrying out the Invention
• the reference numeral 1 generally designates a fire tube boiler with a burner 2, a furnace 3, a flue gas reversal chamber 4a, a vessel 5 which contains the water to be heated with couplings 5a, 5b respectively for inflow and outflow, pipes 6 designed to convey the gases generated by combustion in the furnace which arrive from the reversal chamber 4a and are sent to the output chamber 4b according to the arrows shown in figure 1.
• the boiler 1 is of the type known as condensing boiler, and therefore the water vapor contained in the flue gases condenses therein as they flow within the pipes such as 6; the structure of said boiler is made of carbon steel.
• An important characteristic of the invention consists in that the pipe 6 is made of carbon steel and comprises internally, bonded thereto, a layer 7 made of a corrosion-resistant material, such as aluminum or stainless steel.
• the layer 7 is present along the entire length of the pipe 6, but it should be clearly noted that such layer might be provided only in the part of the pipe toward the outlet of the flue gases.
• An embodiment of the pipe according to the invention is shown in
• the carbon steel pipe 8 comprises, bonded thereto, a layer 9 made of corrosion-resistant material and accommodates internally a coaxial sleeve 10, which is closed by at least one plug 10a, likewise made of corrosion- resistant material.
• An interspace 11 for conveying the flue gases in a reduced cross- section is thus provided: the consequent increase in speed effectively helps to increase heat exchange between the flue gases and the water to be heated.
• a further increased efficiency of said exchange occurs in the variation of Figure 4, in which a carbon steel pipe 12 has, bonded thereto, a layer 13 of corrosion-resistant material, and a sleeve 14, closed by a plug 14a, has ribs 14b which extend monolithically from it and which, by entering an interspace 15 through which the flue gases flow, make contact with the layer 13, transmitting thereto, and ultimately to the water to be heated, heat by conduction.
• An identical situation occurs in the variations of Figures 5, 6, 7, and
• FIG. 9 provides, bonded to a carbon steel pipe 20, a first layer 21 made of corrosion-resistant material, and a second layer 22, also made of corrosion-resistant material, which provides ribs 22a adapted to make contact, by entering an interspace 23 through which the flue gases flow, with a sleeve 24 closed by a plug 24a, thus providing a situation which is similar to the one described earlier.
• Figures 14 to 18 replicate the constructive embodiments shown in Figures 9 to 13, with the only difference related to the fact that there is just one layer made of corrosion-resistant material bonded to the carbon steel pipe: thus, for example, the variation of Figure 14 provides, bonded to a carbon steel pipe 25, only a layer 26 made of corrosion-resistant material, which is provided with a ribs 26a which make contact with a sleeve 27.
• Figure 19 illustrates an embodiment in which a first layer 29, made of corrosion-resistant material, and a second layer 30, also made of corrosion- resistant material, are bonded to a carbon steel pipe 28; ribs 30a protrude from said second layer and are alternated with ribs 31a which protrude from a sleeve 31 , leaving spaces 32 between said ribs for the flow of the flue gases: ribs 31a extend until they make contact with the layer 30 in the presence of references 31b which ensure correct positioning.
• a variation of the embodiment of Figure 19 is shown in Figure 20: the only difference is the absence of the layer 29 bonded to a carbon steel pipe 33, and therefore only a layer 34 made of corrosion-resistant material and provided with the ribs as described above, is present.
• the variation shown in Figure 21 comprises, bonded to a carbon steel pipe 35, a layer 36 made of corrosion-resistant material, which is provided with variously shaped ribs 36a arranged alternately with respect to variously shaped ribs 37a which protrude from a sleeve 37 and are adapted to make contact in the presence of references 37b with the wall of the layer 36.
• the reference numeral 38 designates a carbon steel pipe, which comprises internally two flue gas conveyance modules, designated generally by the reference numerals 39 and 40 respectively, which are delimited by a closed wall made of corrosion-resistant material.
• the wall of the module 39 comprises a portion 41, which is bonded to the wall of the pipe 38 substantially along half of the circumferential extension thereof, and a straight portion 42, which extends transversely, and likewise the wall of the module 40 comprises a portion 43 bonded to the wall of the pipe 38 and a straight portion 44; the straight portions 42 and 44 are in mutual contact.
• the described configuration allows to obtain the dual result of protecting the wall of the pipe 38 against contact with the flue gases, and this is done by the portions 41 and 43 of the walls of the modules, and of providing an intense transmission of heat from the flue gases to the water contained in the boiler which strikes the outer surface of the pipe 38, determined by the presence of the portions 42 and 44 of said walls which make contact with the flue gases at the region where said flue gases have a particularly high temperature.
• Figure 23 illustrates another variation of the invention, which provides, inside the pipe 38, six flue gas conveyance modules which are substantially shaped like wedges and are designated respectively by the reference numerals 45, 46, 47, 48, 49, 50.
• the walls of the module which are made of corrosion-resistant material, are identical and comprise an arc-like portion, 45a for the module 45, bonded to the wall of the pipe 38, and two straight portions 45b, 45c for said module, which protrude from the ends of said arc-like portion toward the axis of said pipe; the straight portions of the individual modules are in mutual contact.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Geometry (AREA)
• Rigid Pipes And Flexible Pipes (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
• Laminated Bodies (AREA)
• Incineration Of Waste (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=36581553

Family Applications (1)

Country Status (5)

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• 2006
  • 2006-04-12 WO PCT/EP2006/003381 patent/WO2006111315A1/en active Application Filing
  • 2006-04-12 EP EP06724287A patent/EP1872080A1/de not_active Withdrawn
  • 2006-04-12 CA CA002603454A patent/CA2603454A1/en not_active Abandoned
  • 2006-04-12 US US11/887,638 patent/US20090266529A1/en not_active Abandoned
  • 2006-04-12 EA EA200702265A patent/EA011432B1/ru not_active IP Right Cessation

Non-Patent Citations (1)

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