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
  • F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
  • F28F19/002—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using inserts or attachments
• • 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
  • F28F13/02—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by influencing fluid boundary
• • 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

Definitions

• the invention relates to a heat exchanger having systems of first channels for cold media flow and a second channels for hot media flow.
• Heat exchangers comprise evenly spaced and mutually parallel arranged desks defining channels for hot and cold media flows.
• the exchanger with media counter-flow having inlet and outlet of the media being arranged at the same side is often named as U-type exchanger while the one with inlet and outlet of the media on opposite sides is called a Z-type exchanger.
• Typical constructions are known from the paper WO 92/09859 describing an exchanger with a media cross-flow and from the paper WO 96/19708 dealing with an exchanger having a media counter-flow.
• a heat exchanger having systems of first channels for cold media flow and a second channels for hot media flow designed in accordance with the present invention, the exchanger being provided with means for creating layers of heated media separating at least a part of space for the cold media flow from the hot media energy transfer surface.
• the said means for creating a layer of warm media are arranged within the area of cold media inlet.
• the means for creating a layer of warm media comprise inserts located in each of the first channels, the inserts being spaced apart from the first channel walls, while at the cold media inlet side the interjacent space between the first channel wall and the insert is closed.
• the means for creating a layer of warm media comprise inserts located in each of the first channels, the inserts being spaced apart from the first channel walls and at the cold media inlet side the interjacent space between the first channel wall and the insert is interconnected with the first channel inside space, while the cold media inlet consists of jets opening into the inside space of the first channels.
• the means for creating a layer of warm media are provided for by paths for a return flow of pre-heated media, the paths having their inlets at the side of heated media output and outputs leading into a common space at the side of cold media inlet through which there are extending the jets for input of the cold media, the jets opening into the inside space of the first channels.
• a layer of pre-heated media is created within the cold media inlet area.
• Such a layer provides for thermal conditions allowing no vapour condensation and corrosion of inside surfaces of channels hot media flow.
• Fig. 1 shows design of one tube of a channel for cold media flow by a tube type exchanger with a static protective layer of pre-heated media.
• Fig.2 presents a similar embodiment by a desk type exchanger.
• Fig. 3 illustrates a longitudinal section through one tube of the channel for cold media flow of a tube type exchanger having a dynamic protective layer of pre-heated media and on Fig. 4 there is a partial vertical longitudinal section through a similar embodiment.
• Fig. 5 shows a vertical longitudinal section through a channel for cold media flow by a tube type exchanger, the protective layer being provided for by a return flow of a part of the heated media and the Fig. 6 shows a horizontal section through a the channel for cold media flow by a desk type exchanger being of a similar embodiment as on Fig. 5
• heat-exchanging media means cold medium and hot medium which flow into the exchanger and flow out as heated and cooled media resp.
• warm medium describes originally cold medium partially heated during transport through an exchanger.
• the heat-exchanging media may be represented by water or gas, the term cold medium applies for any matter which is to be heated.
• Fig. 1 representing a section of a tube type heat exchanger.
• Cold media flow channels 1 are provided for by tubes 2 passing through a hot media flow channel 3.
• each tube 2 is furnished with a tubular insert 5 which is by means of spacers 6 spaced apart from the tube 2 inside surface.
• the space between the tube 2 and the tubular insert 5 is closed at the side of the cold media inlet 4.
• the cold media flow contacts only the tubular insert 5, while within the space between the tubular insert 5 and the tube 2 inside surface there is an air cushion of warmed media.
• the cold media flow does not act directly upon the wall of the hot media flow channel 3 and within a section running along the tubular insert 5 an outside surface of tubes 2 is cooled less intensive. Therefore no condensation of vapours within the hot media flow channel 3 occurs.
• FIG. 2 Spaced apart plates 7 define first channels 1 for cold media flow and second channels 2 for hot media flow.
• Each channel 1 for cold media flow is provided with flat inserts 8 located adjacent to a cold media inlet 4.
• the flat inserts 8 are my means of spacers spaced apart from the first channel 1 inside surface. The space between the plate 7 and the adjacent flat insert 8 is closed at the side of the cold media inlet 4. When entering the exchanger the cold medium contacts only the flat insert 8.
• the said layers of heated media separating parts of cold media flow channels 1 from surfaces for transfer of hot media energy prevent extensive cooling of walls of the hot media flow channels 3.
• the above described feature gives an effective protection against vapour condensation in the hot media flow channels 3 at the cold media inlet 4 sides.
• the protective layers of heated media by the above described embodiments practically do not move, their possible movement is negligible and has no influence upon the effect of the layer. Therefore such a protective layer can be described as a static protective cushion.
• To prevent movements of the layer mechanical barriers could be installed. It is not necessary to prevent any movement of the layer, it is sufficient to minimize it to negligible extent. It is also possible to provide for a dynamic protective layer as described below.
• Fig. 3 illustrates a design providing for the dynamic protective layer by a tube heat exchanger.
• the basic construction of the exchanger is the same as the one presented on Fig. 1.
• the .cold media flow channels 1 are provided for by tubes 2 passing through a hot media flow channel 3.
• each tube 2 is furnished with a tubular insert 5 which is by means of spacers 6 spaced apart from the tube 2 inside surface and arranged spaced apart from an outside seal 9 at the cold media inlet 4.side of the cold media flow channel 1.
• a cone-like jet K protrudes through the seal 9 and opens into the inside of the tubular insert 5.
• the cold media flow running into the first channel 1 produces suction effect resulting into back-flow of a part of already heated media through a gap between the tubular insert 5 and the tube 2 into the entry part of the cold media flow channel 1.
• a pre-heated medium thus flows around the tubular insert 5 and increases the effect of the warm protective cushion.
• the tube 2 In its entry part the tube 2 has no direct contact with the cold media flow and the tube 2 outside surface inside the hot media flow channel 3 is not excessively cooled and no vapour condensation and consequent undesired corrosion may occur.
• the above described design with jets 10 can be applied also by plate-type heat exchangers, as shown on Fig. 4.
• the cone-like shape of the jets is here replaced by elongated shape occupying full width of each of the cold media flow channels 1.
• FIG. 5 shows a corresponding construction by a heat exchanger of the tube type.
• the cold media flow channels 1 comprise two systems of tubes.
• Cold medium enters the exchanger through funnel-type jets IO directly only into primary tubes 2J .
• a system of intermediate tubes 22 serves for return flow of a part of already warmed media.
• the cold medium entering through the jets IO into the primary tubes 21 produces at the inlet suction effect.
• Static pressure at an outlet 15 of the system of primary tubes 2J . is higher than pressure in a common space 16 of both tube systems at the cold media inlet 4. This fact results in a return flow of a part of warmed medium from the outlet side back towards the inlet side.
• the warm medium is further heated by the hot medium surrounding the system of intermediate tubes 22. Therefore temperature inside the common space 16 of both tube systems is significantly higher than the entering cold medium temperature.
• the cold medium flow running through the jet 10 sucks the warmed medium from the common space 16 of both tube systems into the primary tubes 21 the flow of sucked medium having a form of a ring-shaped flow.
• the ring-shaped flow of the warmed medium creates the protective layer preventing direct contact of the cold medium with walls of the hot medium flow channel 3.
• no excessive cooling of the walls occurs and therefore no undesired vapour condensation inside the hot medium flow channel 3 appears.
• the double system of the cold media flow channel 1 of the tube-type heat exchanger can be applied also by the plate-type heat exchanger as shown on Fig. 6.
• Each cold media flow channel 1 is again divided into two systems.
• the first system consists of primary channels 3_1 arranged in parallels, the second system comprise intermediate channels 32.
• Each primary channel 3_1 has its own jet 1P_ providing for inlet of the cold medium flow.
• the cold medium entering through the jets 10 into the primary channels 3_1 produces at the inlet suction effect allowing for draw of a flow of the already warmed medium from the intermediate channels 32 into the primary channels 31 Heat energy of this flow warms hot medium flow channel 3 walls located over and below the respective cold medium flow channel 1 and prevents creation of conditions for vapour condensation and consequent wall corrosion in the adjacent hot medium flow channel 3
• the present invention is designed for heat exchangers of tube or plate construction.

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• 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)

Applications Claiming Priority (2)

Publications (2)

Family

ID=40823620

Family Applications (1)

Country Status (2)

Family Cites Families (4)

• 2007
  • 2007-12-27 CZ CZ20070900A patent/CZ2007900A3/cs unknown
• 2008
  • 2008-12-22 WO PCT/IB2008/003814 patent/WO2009087480A2/en not_active Ceased

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