Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
  • F24H1/22—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating
  • F24H1/24—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers
  • F24H1/26—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body
  • F24H1/28—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body including one or more furnace or fire tubes
  • F24H1/285—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body including one or more furnace or fire tubes with the fire tubes arranged alongside the combustion chamber
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H9/00—Details
  • F24H9/0005—Details for water heaters
  • F24H9/001—Guiding means
  • F24H9/0015—Guiding means in water channels
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D7/16—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged in parallel spaced relation
  • F28D7/163—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged in parallel spaced relation with conduit assemblies having a particular shape, e.g. square or annular; with assemblies of conduits having different geometrical features; with multiple groups of conduits connected in series or parallel and arranged inside common casing
  • F28D7/1669—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged in parallel spaced relation with conduit assemblies having a particular shape, e.g. square or annular; with assemblies of conduits having different geometrical features; with multiple groups of conduits connected in series or parallel and arranged inside common casing the conduit assemblies having an annular shape; the conduits being assembled around a central distribution tube
  • F28D7/1676—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged in parallel spaced relation with conduit assemblies having a particular shape, e.g. square or annular; with assemblies of conduits having different geometrical features; with multiple groups of conduits connected in series or parallel and arranged inside common casing the conduit assemblies having an annular shape; the conduits being assembled around a central distribution tube with particular pattern of flow of the heat exchange media, e.g. change of flow direction
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
  • F28F9/22—Arrangements for directing heat-exchange media into successive compartments, e.g. arrangements of guide plates

Definitions

• the invention relates to a heat exchanger device and a method to provide heat exchange between two media having different temperatures, the device having a shell formed cylindrically or like a prism, the shell is closed in both ends by end closures, and an inner space of the device is defined by the shell and said closures, said inner space having an inlet and an outlet for a first medium, and in the inner space at least one flue isolated from the inner space is arranged to conduct a second medium and having an inlet and an outlet both opened to the outside of the inner space .
• Heat transfer efficiency of recuperators and boilers and generally heat exchangers or heating devices containing thereof depends principally on the coefficient of heat transfer of a surface forming the boundary layer between a heating medium and a medium to be heated, therefore it depends on the degree of heat transfer occurred through that surface.
• the longer the period spent by the medium to be heated next the boundary surface and most of its particles participate in the heat exchange the greater the temperature obtained by the same. Consequently, flow speed of the medium is a substantial factor in connection of heat exchange.
• conventional heat exchangers i.e.
• boilers with fire tubes hot flue gases flow in runs arranged in line of each other (e.g. parallelly arranged) from the burner, through the fire tube then the first and second draughts of flue tubes, to the exhaust exit.
• Bunches of flue tubes are arranged in a vessel, i.e. inside the shell of the boiler, in which a medium to be heated, e.g. water is coursed between the wall of the boiler and the flue tubes. Water flowing along the flue tubes will be heated, then it exits through the hot water outlet.
• a medium to be heated e.g. water
• Main disadvantage of such a heat exchanger is having dead areas formed inside the shell space, where the medium to be heated stops flowing (stagnates) and therefore it hardly participates in the heat exchange process.
• Each baffle element consists of planar surfaces connecting to each other by perpendicular step like connections arranged sequentially and forcing the medium to be heated to flow helically in the shell.
• An advantage of the solution is that it considerably enhances the heat exchange between media, but it has the disadvantage of causing dead points at the perpendicular connecting areas of the baffle members.
• Patent Application No. US 4 787 440 discloses a method to induce helical and longitudinal flow of a medium to be heated in a heat exchanger by means of arranging rods in different groups and directions between the flue tubes, and these rods force the medium to flow helically.
• the object of the invention is to provide a heat exchanger in which the full amount of medium to be heated can flow helically around the flue tubes without creating dead points and overheated surfaces resulting in an excellent heat transfer between the flue gases and the heated medium. Owing to the solution according to the invention heat transfer efficiency of the heat exchanger will be substantially enhanced, consequently the necessary heating surface and even the overall measure of the structure can be reduced.
• a heat exchanger is provided to achieve heat exchange between two media having different temperatures, the device having a shell formed cylindrically or like a prism, the shell is closed in both ends by end closures, and an inner space of the device is defined by the shell and said closures, said inner space having an inlet and an outlet for a first medium, and in the inner space at least one flue isolated from the inner space is arranged to conduct a second medium and having an inlet and an outlet both opened to the outside of the inner space, wherein between end closures and inside the inner space of the shell a baffle means having a helical surface is arranged, and at least a bore hole is prepared on said baffle means, and the at least one flue is conducted through said bore hole.
• the first medium is a medium to be heated
• said second medium is a heating medium.
• Said flue consists of a central fire tube forming first draught and at least one flue tube connected thereto by means of a first smoke-drum, and said flue tube is inserted into bore holes formed on said baffle means.
• the at least one flue tube consists of a flue tube bunch forming second draught and a further flue tube bunch forming third draught and second and third draught are connecting by means of a front reversing drum.
• the fire tube, the flue tube bunch forming second draught, and the flue tube bunch forming third draught are parallelly arranged to the axis of the baffle means having helical surface.
• the flue tube and the shell are fitted to the baffle means by leaving a mounting gap between them.
• the heating medium is selected advantageously from the group containing steam, hot or warm water, thermo oil, exhaust gas, and the medium to be heated is a gas or a fluid, preferably water.
• the fire tube is located close to the bottom of the inner space, or in the longitudinal axis thereof.
• An external surface of the fire tube is corrugated, or it is provided with ribs, preferably helical ribs, in order to enhance heat exchange.
• the heat exchanger is provided preferably by at least two flue tubes arranged parallelly. The first medium is to be cooled and the second one is a cooling medium.
• a method to achieve heat exchange between two media having different temperatures comprising a step of conducting a first medium into an inner space defined by a shell formed cylindrically or like a prism and closed in both ends by end closures, through an inlet for the first medium, and remove said first medium from the inner space of the shell through an outlet, and flowing a second medium in at least one flue isolated from the inner space and having an inlet and an outlet both opened to the outside of the inner space, and said first medium is flowed along a helical surface of a baffle means arranged between said end closures and inside the inner space of the shell, and the at least one flue is conducted through at least one bore hole prepared on said baffle means.
• the first medium is advantageously heated by the second medium.
• the method preferably achieved by using a flue tube containing a central fire tube forming a first draught and at least one flue tube connected thereto by means of a first smoke-drum, and inserting said flue tube into bore holes formed on said baffle means.
• the method advantageously achieved by conducting steam, hot or warm water, thermo oil, exhaust gas into the flue tube, and flowing a gas or a fluid, preferably water, in the inner space of the shell.
• the method preferably achieved by cooling the first medium by the second cooling medium.
• FIG. 1 is an embodiment of the heat exchanger according to the invention, formed as a boiler provided with a tube bunch
• the Figure 2a shows a possible way of arranging the tube bunch
• the Figure 2b shows a further possible way of arranging the tube bunch
• the Figure 3 shows an embodiment of the heat exchanger according to the invention, formed as a recuperator.
• a preferred embodiment of a heat exchanger according to the invention is shown.
• This heat exchanger is a shell-and-tube boiler 1 showed in broken-out section view and adapted to achieve indirect heat exchange between two media having different temperatures.
• Boiler 1 is provided with a burner 7 and a shell 2 defining an inner space 3 having an inlet 13 to conduct a first medium into the inner space 3 and an outlet to remove that medium from the shell 2.
• the shape of the shell 2 is preferably in the form of a cylinder closed at its ends by end closures 8, such as cover plates.
• end closures 8 such as cover plates.
• the heat exchanger according to the invention may be formed with a shell shaped differently from the cylinder, i.e. with a square or rectangular cross section (like a column) these shapes generates dead areas in the inner space 3.
• a flue 19 isolated from the inner space 3 is arranged in the inner space 3 in order to conduct a second medium, and having an inlet 15 and an exhaust outlet 16 both opened to the outer side of the shell 2.
• said second medium conducting flue 19 arranged in the cylindrical inner space 3 of the shell 2 of the boiler 1 consists of a fire tube 4 forming a first draught and placed in the longitudinal axis L of the inner space 3, and flue tubes 5 forming second draught and arranged around the fire tube 4, as well as further flue tubes 5 forming a third draught and arranged in a tube bundle 17.
• flue tubes 5 are extending in the direction of the inlet 15 and emptying into a front reversing drum 6a. From the front reversing drum 6a further flue tubes 5 of the tube bundle 17 extend in the direction of the exhaust outlet 16.
• the second medium namely the heating medium, may be steam, hot or warm water, thermo oil etc., and the medium to be heated is a gas or a liquid, preferably water.
• First medium to be heated e.g. water
• the fire tube 4, flue tubes 5, and flue tubes 5 of the bundle 17 are fitted into the bore holes formed on the helical baffle means 9 by leaving a mounting gap well known from the state of the art.
• the size of the mounting gap may be so small, that the fire tube 4, flue tubes 5, as well as flue tubes 5 of the bundle 17 can easily be fitted into the holes during construction or tube exchange, but it does not disturb actually the flow of the first medium, that is very small amount of fluid can flow across said gaps.
• External surface 11 of the fire tube 4 is corrugated, or it is provided with ribs 12, preferably helical ribs 12, in order to enhance heat exchange.
• Ribs 12 might be arranged advantageously in the form of a single helical rib 12 following continuously the stream of the flow.
• the surfaces 10 are flat, however these may also be formed with helical or concentric ribs further enhancing constant heat transfer into the medium to be heated without resulting in undesired cavitations appearing on the surfaces 10.
• First medium to be heated e.g. water
• entered the internal space 3 through the inlet 13 flows along a helical path between adjacent surfaces 10 of the baffle means 9 and around the fire tube 4, the flue tubes 5 and flue tubes 5 of the tube bundle 17. It can be shown, that along the path of the flow there are no dead areas, where the flow of the water can be blocked and its heat absorption intensity would be reduced.
• the flue tubes 5 of the heat exchanger and the tubes of the tube bundle 17 are located symmetrically in the inner space 3, in a helical arm-like arrangement.
• the medium to be heated is not determined to a helical forced flow only, but also diverted onto the fire tube 4 (as a member having the highest calorific output), hence a more intense heat exchange will be formed around the fire tube 4.
• Figure 3 demonstrates a heat exchanger according to the invention, which is adaptable to a recuperator. The heating medium having higher heat content is inflowed through an inlet 15 into the flues 19 arranged in the inner space 3.
• Heating medium flowing in the flues 19 warms up the first medium to be heated guided by the helical baffle means 9 arranged in the inner space 3, in a manner as it was described above in connection of the Figure 1 , then it exits through an outlet 16.
• Medium to be heated may be inflowed both at the inlet 13 or outlet 14, since due to the quasi perpendicular arrangement of the flow direction of the first medium (to be heated) and the flues 19, the direct current application as well as the countercurrent application of the heat exchanger according to the invention allows a practically equivalent degree of heat exchange. Therefore, providing a heat exchanger according to the invention it can be achieved a process, by which the indirect heat exchange between two media having different temperatures comes off without formation of dead areas.
• a first medium may be inflowed into the inner space 3 of the shell 2 through an inlet 13, then the first medium will be outflowed from the shell 2 through an outlet 14 while making the first medium flowed along the helical surfaces 10, between the threads of the baffle means 9 actually, around the flue 19 isolated from the inner space 3 and conducting a second medium there inside.
• the helical baffle means 9 is provided by at least one, preferably more than one bore hole to fit the tubes of the flue 19, and the draughts of the flue 19, namely the fire tube 4, the flue tubes 5 and tube bundle 17 are introduced into that holes, the first medium flowing along the helical surface 10 of the baffle means 9 receives a greater amount of heat from the second medium as it is the case of no baffle means 9 being present, and the absorption of heat is also more equable.
• steam hot or warm water, and thermo oil may be flowed as a second or heating medium, and into the inner space 3 a gas or liquid material, preferably water may be conducted.
• the method according to the invention also applicable to cool a first medium.
• the heat exchanger according to the invention is applicable equally as a boiler heated by steam, hot or warm water, thermo oil, or exhaust gases to heat a first medium to be heated like a gas or a liquid, but if the first medium is a medium to be cooled the second one is a cooling medium. In the latter case the heat exchanger may operate as a cooling device, i.e. a 'continuous' refrigerator for fluids.
• the heat exchanger according to the invention allows a more effective heat transfer and therefore also a smaller heating surface relative to the solutions according to the state of the art, therefore the necessary overall sizes of the heat exchanger may be reduced.
• the best feature of the heat exchanger is that the whole amount of the first medium may flow closely around the tubes of the flue 19 without forming dead areas, and it receives the greatest proportion of the heat content of the heating medium (in the case of heating operation).
• the heat transfer achieved by the surfaces of the heat exchanger disclosed hereabove is even and balanced, consequently the local overheat of structural elements does not bring about local stresses.
• the heat transfer efficiency of a heat exchanger will be enhanced and necessary heating surface of the heat exchanger may be reduced, therefore the overall size of the device will be smaller.
• the heat exchanger according to the invention is therefore economical, and it has even a longer life time of operation or a smaller space demand.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Geometry (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=89981746

Family Applications (1)

Country Status (2)

Cited By (8)

Citations (5)

• 2003
  • 2003-11-04 HU HU0303606A patent/HUP0303606A2/hu unknown
• 2004
  • 2004-11-04 WO PCT/HU2004/000102 patent/WO2005043061A1/en active Application Filing

Patent Citations (5)

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