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
  • 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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
  • F05C2225/00—Synthetic polymers, e.g. plastics; Rubber
  • F05C2225/08—Thermoplastics

Definitions

• the invention relates to a heat exchanger, in particular for heating and cooling machines operating according to a regenerative gas cycle process, with separation of the media participating in the heat transfer, a tube provided with fins increasing the heat transfer area serving as a flow channel for a heat-absorbing or heat-emitting, preferably liquid medium.
• the invention further relates to a method for producing such a heat exchanger.
• Heating and cooling machines operating according to the Stirling or Vuilleumier cycle have been known for a long time, for example from GB-PS 1 36 1 95.
• they have not found any practical use, mainly because of their constructive nature Difficulties that have hitherto prevented the theoretical advantages of such machines from being realized in practice.
• it must be taken into account that they have to withstand the high pressure differences of, for example, 120 bar on the part of the heat-emitting working medium and approximately 2.5 bar on the part of the heat-absorbing medium.
• the invention is based on the object of creating a heat exchanger which is particularly suitable for heating and cooling machines which operate according to a regenerative gas cycle process and which has a small construction volume and a very small hydraulic diameter for the heat-emitting or heat-absorbing working medium, which moreover has the high pressure differences between the Resists high pressure and normal pressure medium and should also be suitable for other purposes.
• the heat exchanger according to the invention is characterized in that the ribs arranged on the outer lateral surface are provided on their rib heads with an impermeable and thermally insulating covering and that between the covering and the lateral surface of the tube at least one flow channel for the person involved in the heat exchange, preferably by a process gas formed second medium is formed.
• This design according to the invention results in a heat exchanger which, on the one hand, can be manufactured with a small construction volume and, on the other hand, has a very small dead volume on the working medium side, since the rib channels are designed with a minimum width of approximately 0.35 mm and a minimum height of approximately 0.9 mm can.
• Such small hydraulic diameters can be used in particular if the working medium is a process gas.
• the finned tube is wound helically in one or more threads.
• the sheath forming the flow channel for the working medium surrounds the entire single or multi-start spiral. Due to the helical winding of the tube, a particularly compact design with high efficiency is achieved.
• the helix consisting of the coiled tube is constructed in several rows.
• the performance of the heat exchanger can be increased with a compact design.
• Another way to increase the efficiency of a heat exchanger according to the invention is that in a multi-helical heat exchanger, the flow channel formed by the tube for the heat-absorbing or heat-emitting medium is divided into several individual channels with separate inlet and outlet.
• a heat-absorbing medium is used, this introduction of a new heat-absorbing medium and removal of the already heated medium results in a significant improvement in heat transfer without increasing the dead volume on the working medium side and without significantly changing the overall volume of the entire heat exchanger.
• the ribs of at least one helical path at these contact points are bent at a right angle approximately at the height of half their radial extent.
• a compact design with small wall thicknesses, which withstands the high pressure difference between heat-emitting and heat-absorbing medium, can be achieved according to a further embodiment of the invention in that the tube is cylindrical.
• the covering for sealing the rib channel and for forming the flow channel on the working medium consists of a film, preferably an inflation or shrink film.
• the covering consists of a hardenable, pourable material, such as plastic or resin. The viscosity of the materials to be cast is to be selected so that it is low enough to thoroughly enclose the entire heat exchanger before solidification, and high enough so that this material does not penetrate into the rib channel and thus the flow channel for the Working medium closes.
• the covering can be produced in that the gaps between the ribs of the finned tube with the casting the hardening material with wax to prevent penetration of the casting material into the spaces. Following the casting process, the wax is expelled from the flow channels in a melting process.
• the tube and the fins are made of a material with a high heat conduction coefficient.
• the method according to the invention for producing a heat exchanger according to the invention is characterized in that the ribs arranged on the outer circumferential surface of the tube are provided on their fin heads with an impermeable and thermally insulating covering such that at least one flow channel for the medium involved in the heat exchange, preferably formed by a process gas.
• This manufacturing method according to the invention provides a particularly compact heat exchanger with a very low dead volume on the working medium side, which contributes significantly to increasing the efficiency of the heat exchanger according to the invention.
• FIG. 1 shows a longitudinal section through a heat exchanger wound without a sheath to form a catchy coil
• Fig. 2 shows a longitudinal section through the heat exchanger according to FIG. 1, but with casing and
• Fig. 3 is an enlarged detail view according to III. in Fig. 1.
• the heat exchanger shown in the drawing using an exemplary embodiment is intended for use in a heating and cooling machine which operates according to a regenerative gas cycle process, in which the media participating in the heat transfer are separated from one another.
• the heat exchanger comprises a tube 1, which is provided on its outer lateral surface 1 a with ribs 2 to enlarge the heat transfer area.
• the tube 1 for the formation of the heat exchanger is wound into a helix 3.
• the cylindrical tube 1 of the heat exchanger serves as a flow channel for the heat-absorbing or heat-emitting, preferably liquid medium, which is introduced into the tube 1 via the inlet and outlet pipe 4 or led out of the latter.
• the helix 3 As can be seen in FIG. 2, is surrounded by a covering 5, which seals a rib channel 6 so that it extends along the outer lateral surface 1 a of the tube 1 runs a flow channel for the heat-emitting or heat-absorbing medium.
• the sheath 5 consists of a hardening material which has been cast around the helix 3 and abuts the rib heads 2a.
• this pourable material which is preferably made of plastic or resin, must be selected so that, on the one hand, the entire coil 3 is evenly surrounded by the covering 5 before the material cures, but on the other hand the viscosity is high enough so that the covering 5 does not penetrates into the rib channel 6, which would lead to a blockage of the flow channel.
• the flow course does not take place along the entire fin channel 6 and thus along the entire lateral surface of the helically wound tube 1.
• the medium flowing in and out via a ring-shaped inlet 7a and outlet 7b flows in the shortest way - seen in FIG. 2 - from inlet 7a to outlet 7b, namely vertically in the plane of the drawing shown along the superimposed pipes 1, the process medium flowing around each pipe section approximately along its half circumference.
• Fig. 3 shows an enlarged detail view from the area of two superimposed helical gears of the helix 3.
• the ribs 2 of a helical gear are in The area of the contact points is bent at a right angle approximately at the height of their half radial extension, so that the ribs 2 of the next helical path rest on the bend of the lower rib 2. 3, the contact points 8 between the ribs 2 resting on one another are still permeable to the medium flowing through the rib channel 6.
• the heat exchanger can also be designed in multiple rows, for example by coaxially arranging a plurality of coil 3.
• a heat exchanger designed as described above is characterized in that it has a compact construction volume on the one hand and the dead volume on the working medium side is very small on the other hand, since the rib channels 6 have a minimum width of approximately 0.35 mm and a minimum height of approximately 0.9 mm can be manufactured.
• the cost of producing such a heat exchanger is low, since the main component of the heat exchanger, namely the tube 1 provided with a rib 2, as a standard component of many heat exchangers, is not a special component.
• Surrounding the helix 3 with the sheath 5, for example by casting with a plastic or resin is inexpensive to do, since only an inner and an outer shape (not shown) are required as additional components, which fix the material until it solidifies .
• the manufacture of such a heat exchanger is thus technically easy to control and is possible at low cost in series production.

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 (5)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26016739

Family Applications (1)

Country Status (5)

Families Citing this family (1)

Citations (6)

• 1996
  • 1996-07-05 JP JP9505407A patent/JPH10506179A/ja not_active Ceased
  • 1996-07-05 ES ES96922743T patent/ES2168492T3/es not_active Expired - Lifetime
  • 1996-07-05 AT AT96922743T patent/ATE209329T1/de not_active IP Right Cessation
  • 1996-07-05 EP EP96922743A patent/EP0787276B1/de not_active Expired - Lifetime
  • 1996-07-05 WO PCT/DE1996/001205 patent/WO1997003332A1/de not_active Application Discontinuation

Patent Citations (6)

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