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
  • F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
  • F28F3/02—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations
• • 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
  • F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D9/0062—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for one heat-exchange medium being formed by spaced plates with inserted elements
  • F28D9/0068—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for one heat-exchange medium being formed by spaced plates with inserted elements with means for changing flow direction of one heat exchange medium, e.g. using deflecting zones
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F2250/00—Arrangements for modifying the flow of the heat exchange media, e.g. flow guiding means; Particular flow patterns
  • F28F2250/10—Particular pattern of flow of the heat exchange media
  • F28F2250/108—Particular pattern of flow of the heat exchange media with combined cross flow and parallel flow

Definitions

• the present invention relates to an improvement in a plate-fin-type heat exchanger wherein one of a fluid of high temperature side and a fluid of low temperature side performs continuous operation, while the other repeats intermittent operation, and relates to a plate-fin-type heat exchanger wherein thermal fatigue produced particularly in a separating plate partitioning between a high temperature side passage and a low temperature side passage is alleviated by increasing the ratio of hAs (coefficient of heat transfer x area of heat transfer) of the both passages, and thereby the life of the heat exchanger can be extended.
• hAs coefficient of heat transfer x area of heat transfer
• the plate-fin-type heat exchanger has a large area of heat transfer per unit area and a high coefficient of heat transfer, and therefore has an advantage of being made compact easily in comparison with other types, .particularly the tube type heat exchanger.
• the plate-fin-type heat exchanger has a wide range of selection of design such that the fin pitch, the fin height and the fin shape suitable for the nature and the purpose of the fluid flowing through each passage can be properly selected, and further the number of laminations of fins can be selected arbitrarily, and thereby an efficient design can be made, so that it has been used for a variety of applications.
• the temperature of the separating plate between the adjacent passages during operation is given by the following equation.
• T W T H *
• any heat exchanger has not been proposed which has a configuration that the variation in the temperature of the separating plate between the passages is positively minimized, and conventionally materials being strong against the thermal stress have been selected.
• the present invention purposes to provide a plate-fin- type heat exchanger wherein the thermal fatigue is alleviated which is produced in the separating plate partitioning between the passage of high temperature side and the passage of low temperature side of the plate-fin-type heat exchanger wherein one of the fluid of high temperature side and the fluid of low temperature side is operated continuously, while the other repeats intermittent operation, and thereby the life of the heat exchanger is extended.
• a plate-fin-type heat exchanger having a configuration capable of alleviating thermal fatigue produced in a separating plate partitioning between a passage of high temperature side and a passage of low temperature side is aimed and various studies have been conducted, and as a result, utilizing that a corrugated fin which is the feature of the plate-fin-type heat exchanger can be selected arbitrarily, the ratio of hAs (coefficient of heat transfer x area of heat transfer) of the both passages is increased, and thereby the amount of variation in the temperature of the separating plate repeated intermittently can be decreased, and it has been found that a reduction in life due to thermal fatigue can be improved.
• a plate-fin-type heat exchanger wherein one of a fluid of high temperature side and a fluid of low temperature side performs continuous operation, while the other repeats intermittent operation, a plate-fin-type heat exchanger characterized in that passages of the fluid of continuous operation side are disposed outside, and dummy passages passing no fluid are disposed in a laminated fashion on the outermost side, and fins having a high coefficient of heat transfer and a large area of heat transfer are used for a fluid passage of continuous operation side, and fins having a low coefficient of heat transfer and a small area of heat transfer are used for a fluid passage of intermittent operation side.
• the plate-fin-type heat exchanger is configurated in a manner that the passages of high temperature side of a configuration that a corrugated fin is incorporated between two plates and the both ends are closed with side bars and the passages of low temperature side of nearly the same construction are laminated alternately, and the dummy passages which have nearly the same construction as each passage and pass no fluid are laminated outside the both end passages respectively, and further (1) the fin having a high coefficient of heat transfer and a large area of heat transfer is used for the passage wherethrough the heat medium passes continuously during operation, and the fin having a low coefficient of heat transfer and a small area of heat transfer is used for the passage wherethrough the heat medium passes intermittently in a certain time cycle during operation, and the ratio of hAs
• the number of the dummy passages of the outermost side of the heat exchanger core are set to two or more.
• the corrugated fin having a large number of corrugations can be used, and for the fin having a low coefficient of heat transfer and a small area of heat transfer, the corrugated fin having a small number of corrugations can be used, and the corrugated fins of different numbers of corrugations can be used in combination in the same passage, and further different fin materials can be used in combination as required.
• Fig. 1 is an illustrative view showing an A passage of a plate-fin-type heat exchanger in accordance with the present invention.
• Fig. 2 is an illustrative view showing a B passage of the same.
• Fig. 3 is a perspective illustrative view showing the plate-fin-type heat exchanger in accordance with the present invention.
• the plate-fin-type heat exchanger of the present invention is configurated in a manner that a large number of passages wherein a required corrugated fin is sandwiched between separate fins and is closed with side bars are laminated, and air passages of high temperature side (A passage), a cold gas passages of low temperature side (B passage) and dummy passages (D passage) allowing no fluid pass through are laminated in a 59-state-arranged manner as shown below.
• the A passage has a configuration of passing air downward from above, and as shown in Fig. 1, the fin edge lines are lined up vertically and the number of edge lines per unit length (18 fins/inch) is large, that is, the corrugated fin having a large area of heat transfer and a high coefficient of heat transfer (1) is used.
• the B passage has a configuration of passing a cold gas upward from below, and as shown in Fig. 2, the number of edge lines per unit length (12 fins/inch) is large in the center part (the corrugated fin edge lines are lined up vertically) and the outlet part (two-triangular distributing part) except for the inlet part.
• the corrugated fin of low coefficient of heat transfer (3) having a performance of about two-thirds of the coefficient of heat transfer of the A passage is used, and further in the inlet part, that is, two-triangular distributing part in the drawing, the corrugated fin having a low coefficient of heat transfer (2) is used which has the number of edge lines per unit length (6 fins/inch) being one-third of the number of edge lines per unit length of the corrugated fin of the A passage, that is, has a small area of heat transfer.
• the above-mentioned corrugated fin having a high coefficient of heat transfer (18 fins/inch) is used for both the A passage and the B passage, and only one stage of the D passage is provided, and a plurality of stages are laminated in the sequence of arrangement of D, B, A, B, A .... A, B, A, B, D.
• the above-mentioned two kinds of plate-fin-type heat exchanger is operated under the same conditions in a manner that a cold gas is introduced intermittently into the B passages and heat exchanging is performed, and the temperature of the cold gas inlet side at the separating plate between the A passage and the B passage of the outermost side was measured. Then, in the heat exchanger to be compared, the temperature difference was 30°—50° between the case of introducing the cold gas and the case of introducing no gas, but in the case of the heat exchanger in accordance with the present invention, the difference is reduced to about 15 C, and generation of thermal stress can be reduced, and it is understandable that the life of the heater exchanger can be extended.
• the present invention is optimum for the plate-fin-type heat exchanger wherein one of a fluid of high temperature side and a fluid of low temperature side performs continuous operation and the other repeats intermittent operation such as the heat exchanger which, to heat a fluid of low temperature, performs heat exchange by periodically passing the fluid of low temperature through the heat exchanger wherethrough a fluid of high temperature flows all the time, or in reverse, the heat exchanger which, to cool a fluid of high temperature, performs heat exchange by periodically passing the fluid of high temperature through the heat exchanger wherethrough a fluid of low temperature flows all the time.
• the present invention when the present invention is applied to the preheater for reproducing molecular sieve having a configuration that cool waste gas flows periodically into the heat exchanger the whole of which has become the air temperature and heat exchange is repeated intermittently, generation of thermal stress due to the temperature difference can be reduced, and an extended life of the heat exchanger can be achieved, and thereby the best effect can be expected.

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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)

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Citations (6)

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• 1987
  • 1987-12-24 JP JP1987197156U patent/JPH0711325Y2/ja not_active Expired - Lifetime
• 1988
  • 1988-12-22 EP EP89900874A patent/EP0359826B1/en not_active Expired - Lifetime
  • 1988-12-22 WO PCT/JP1988/001291 patent/WO1989005951A1/en active IP Right Grant
  • 1988-12-22 US US07/445,665 patent/US5035284A/en not_active Expired - Lifetime

Patent Citations (6)

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