Classifications

• • 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
  • F28D7/02—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 helically coiled
  • F28D7/022—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 helically coiled the conduits of two or more media in heat-exchange relationship being helically coiled, the coils having a cylindrical configuration
• • 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
  • F28D7/10—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 one within the other, e.g. concentrically

Definitions

• the present invention is related to a heat exchanger providing heat transfer between two mediums.
• the heat exchanger comprises a tubular shell and a finned tube provided in the shell, the fins of the tube being substantially perpendicular to the direction of the tube.
• One medium is flowing in the shell outside the finned tube and the other medium is flowing in the finned tube.
• the heat exchanger is particularly intended for use in vapour condensers, e. g. in connection with heat pumps and similar devices in which the vapour is routed through the shell outside the finned tube and a cooling medium is routed through the finned tube.
• the finned tubes are advantageous due to their large heat transfer surfaces. While these prior art heat exchangers can be used for condensing vapour, they have in this use the disadvantage that the condensate has a tendency to remain on the fin surfaces, thus reducing the capacity of the heat exchanger and causing a slow down of the condensation process. Disclosure of Invention The main object of the invention is to provide a heat exchanger utilizing the advantage of the large heat transfer surfaces of the finned tubes but eliminating or at least reducing the tendency of the condensate to remain on the heat transfer surfaces. According to the invention, this object is obtained by a heat exchanger having the features set forth in the claims.
• the shell is divided into two chambers provided on either side of the finned tube, one medium. can flow between the fins of the finned tube in good contact with the fins, thus providing a good heat transfer between the medium flowing in the shell outside the finned tube and the medium flowing in the finned tube. Due to the fact that the tube fins abut two opposite walls of the shell, a good heat transfer is provided between the finned tube and the shell, so that also the shell will form a heat transfer surface for further improving the heat exchange between the two mediums passing through the heat exchanger.
• the finned tube By positioning the finned tube diagonally in the shell , so that at the inlet end of the shell the first chamber occupies the larger portion of the space available outside the finned tube and at the outlet end of the shell the other chamber occupies the larger portion of the space available outside the finned tube, a comparatively large inlet and outlet can be provided, although the shell has a small cross section area.
• comparatively large amounts of the first medium can be fed into the shell, enabling the transfer of large amounts of heat between the two mediums.
• the heat exchanger is used for condensing vapour, the vapour being fed into the shell and a cold medium, e.g.
• the vapour flowing between the fins will remove the condensate from the fin surfaces, so that the condensate does not remain on the fins and prevent further condensation.
• the first: chamber i.e. the inlet chamber
• the second chamber i.e. the outlet chamber.
• Figure 1 is a side view of a finned tube having a surrounding straight shell.
• Figure 2 is a cross section through the shell along the line II-II in Figure 1.
• FIG 3 is an embodiment according to Figures 1 and 2 in which the shell has been wound to a coil.
• the embodiment of the invention shown in Figure 1 comprises a tubular outer shell 10 having a substantially oval cross section, as shown in Figure 2.
• a finned tube 11 is inserted in the shell 10.
• the fins 12 of the tube consist of annular. discs provided substantially perpendicularly to the longitudinal direction of the tube.
• the fins of the tubes of this type are normally made by rolling and turning tubes 'having thick walls, so that the fins form an integral part of the tube. Alternatively, the fins can form a helix surrounding the tube along its length.
• the fins 12 of the finned tube 11 abut two opposite walls of the shell 10, as shown in Figure 2.
• This abutment will provide a good heat transfer between the finned tube 11 and the shell 10, so that also the inner surface of the shell will provide a heat transfer surface for heat transfer between the two mediums flowing through the shell and the finned tube.
• the shell having a larger cross section area than the finned tube, is divided into two chambers 13,14 by the finned tube 11, the chambers running from one end of the shell to the other and. being provided on either side of the finned tube, so that the medium entering the first chamber 13 has to flow between the fins 12 of the tube to enter the second chamber 14.
• the shell 10 is a straight tube into which a straight finned tube 11 has been inserted diagonally, so that at the inlet end of the shell the first chamber 13 occupies the larger portion of the space available outside the finned tube and at the outlet end the second chamber 14 occupies the larger portion of the space available outside the finned tube.
• This will facilitate the attachment of an inlet pipe 15 and an ou ⁇ let pipe 16, respectively.
• the pipes 15,16 can be comparatively thick, although the shell has a small cross section.
• the finned tube 11 is also provided with an inlet pipe 17 and an outlet pipe 18 for the medium flowing through the finned tube, the inlet and outlet pipes, however, being reversed as compared with the corresponding pipes of the shell, so that the two mediums will flow in opposite directions through rhe heat exchanger.
• the flow directions of the mediums have been indicated by arrows in Figure 1.
• the heat exchanger according to the invention can be used for condensing vapour. If so, the shell of the heat exchanger is preferably designed as an upright coil having a steep pitch.
• An embodiment of this type has been shown in Figure 3, where the same reference numerals as in Figure 1 have been used for the corresponding elements.
• the finned tube 11 has been positioned diagonally in the shell 10 also in this embodiment, so that the connection pipe 17 of the finned tube at the outlet end of the shell is situated in the upper portion of the shell and the connection pipe 18 at the inlet end of the shell is situated in the lower portion of the shell.
• the first chamber 13 of the shell is positioned above the second chamber 14.
• the shell has an oval or elongate cross section.
• the shell can also have a circular cross section, but in that case sealing elements have to be provided between the finned tube and the walls of the shell, so that two separate chambers are formed in the shell, ⁇ he chambers being connected to each other only through the spaces between the fins of the tube.
• sealing elements may be used also when the shell has an oval or elongate cross section.
• the finned tube must not necessarily run diagonally through the shell but can alternatively run along the central axis of the shell.
• the shell must be sealed at its ends by special walls.
• the closure of the shell at the ends may be provided by deformation of the shell to contact with the inlet and outlet pipes, the complete sealing then being provided by e.g. soldering.
• the elongate cross section of the shell preferably can have its longer axis in parallel with the axis of the coil, as this will make it easier to wind the coil with a small diameter.
• the lower wall of the shell has a shape that at least slightly differs from the shape of the fins, so that the condensate can flow in the shell along the full length of the shall.
• the heat exchanger can also advantageously be used for evaporation, if a hot medium is forced through the finned tube.

Landscapes

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

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20343392

Family Applications (1)

Country Status (7)

Cited By (2)

Citations (7)

• 1981
  • 1981-03-20 SE SE8101808A patent/SE445138B/sv not_active IP Right Cessation
• 1982
  • 1982-03-19 WO PCT/SE1982/000077 patent/WO1982003270A1/en not_active Ceased
  • 1982-03-19 EP EP19820901030 patent/EP0074384B1/en not_active Expired
  • 1982-03-19 JP JP57501111A patent/JPS58500378A/ja active Pending
  • 1982-03-19 DE DE8282901030T patent/DE3262274D1/de not_active Expired
  • 1982-11-19 DK DK516682A patent/DK151357C/da not_active IP Right Cessation
  • 1982-11-19 FI FI823977A patent/FI74806C/fi not_active IP Right Cessation

Patent Citations (7)

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