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
  • F28F3/04—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being integral with the element
  • F28F3/042—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being integral with the element in the form of local deformations of the element
  • F28F3/046—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being integral with the element in the form of local deformations of the element the deformations being linear, e.g. corrugations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D13/00—Corrugating sheet metal, rods or profiles; Bending sheet metal, rods or profiles into wave form
  • B21D13/02—Corrugating sheet metal, rods or profiles; Bending sheet metal, rods or profiles into wave form by pressing
• • 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
• • 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

• This invention relates to a low cost, distortion resistant heat transfer plate for use in a heat ex ⁇ changer such as a gas turbine recuperator or other type of primary surface heat exchanger.
• the inven ⁇ tion also relates to a metal working method for efficiently and easily forming a heat transfer plate out of ductile sheet metal and to apparatus for forming an undulatory pattern of uniform pleats in * sheet metal designed especially for use as a heat transfer plate in a primary surface heat exchanger .
• One technique for forming such heat exchanger plates includes forming a large number of corrugations or pleats in ductile sheet metal of relatively thin gauge.
• the corrugation pleats are given a wavy (or curvilinear) configuration in plan view.
• the pleat crests of one plate form at least some points- of contact with the crests of the adjacent plates.
• An example, of this type of corrugated heat exchanger plate is illustrated in U.S. Patent No. 3,759,323, to Dawson et al.
• the present invention is directed to a low cost, structurally rigid heat transfer plate for use in a heat exchanger wherein the plate is designed to overcome the deficiencies of the prior art as des ⁇ cribed above.
• the heat exchanger plate of the present invention is provided with an undulatory pattern of pleats for forming fluid flow passages on opposite sides of the plate, wherein the side wall of each pleat has a constant slope throughout the length of each fluid flow passage. This uniformity in slope provides greater structural rigidity and over-all uniformity to the heat exchanger plate.
• the present invention further provides a method and apparatus for forming a heat exchanger plate having an extremely rigid, uniform characteristic.
• the method includes the steps of successively bending a sheet of ductile heat conducting material to pro- Jerusalem a series of undulatory pleats forming two sets of curvilinear fluid flow passages on opposite sides of the heat exchanger plates wherein the bending steps are controlled in a way to cause the slope of the side walls of each pleat to be constant along the entire length of the corresponding flow passages.
• Yet another object of this invention is to pro ⁇ vide an apparatus for forming a heat exchanger plate having uniformly sloped pleats including a plurality of cooperating fluid passage forming blades wherein at least one blade has a curvilinear configuration in plan view and a uniform thickness. This blade is positioned for relative reciprocal movement be ⁇ tween second and third fluid passage forming blades each having a non-uniform cross-sectional area.
• the clearance between the first blade and each of the second * and third blades is uniform throughout the operative length of the blades to insure a con ⁇ stant slope in the pleats of a plate formed by the apparatus.
• a more particular object of the subject inven ⁇ tion is to provide a heat exchanger plate including undulatory pleats for forming a set of donative fluid flow passages on one side and a set of recipient fluid flow passages on the other side interleaved with the donative fluid flow passages, wherein the cross-sectional area of each donative fluid flow passage varies in a manner to cause the clearance between the respective fluid passages to be constant.
• a more specific object of the subject invention is to provide a heat exchanger plate including un ⁇ dulatory pleats forming recipient fluid flow passages having a uniform cross-section of the type described above wherein each pleat defines a curvilinear peri-
• Each side wall may be subdivided into a plurality of wave length por ⁇ tions which, in plan view, includes a first circular arc surface on one side of the side wall and a second circular arc surface on the opposite side of the side wall. Both the first and second circular arc surfaces have the same center of curvature.
• a re ⁇ maining section of each wavelength portion of a side wall includes a third circular arc surface and a fourth circular arc surface in the plan view wherein the third and fourth circular arc surfaces have a coincident center of curvature on the side of the side wall opposite to the center of curvature of the first and second circular arc sections.
• Fig. 1 is an exploded perspective view of a plurality of heat exchanger plates designed in acc ⁇ ordance with the subject invention as such plates would be employed in a primary type heat exchanger;
• Fig. 2 is a cross-sectional view of an apparatus designed in accordance with the subject invention for forming a heat exchanger plate having distortion resistant uniform undulatory pleats
• Fig. 3 is a cross-sectional view of the apparatus illustrated in Fig. 2 wherein portions of the apparatus have been moved to an open position in preparation for a pleat forming operation;
• OMPI Fig. 4 is a cut-away perspective view of a prior art pleating apparatus
• Fig. 5 is a cross-sectional view of the prior art pleating apparatus illustrated in Fig. 4 as such apparatus would appear when moved to the position illustrated in Fig. 2, the cross-sectional view being taken along lines 5-5 of Fig. 2;
• Fig. 6 is a partial cross-sectional view of the pleat forming apparatus of Fig. 5 'as taken along lines 6-6;
• Fig. 7 is a partial cross-sectional view of the pleat forming apparatus of Fig. 5 taken along lines 7-7;
• Fig. 8' is an exploded, cutaway, perspective view of a pleat forming apparatus designed in accor ⁇ dance with the subject invention
• Fig. 9 is a cross-sectional view of the pleat forming apparatus illustrated in Fig. 8 as such would appear when moved to the position illustrated in Fig. 2, the cross-sectional view being taken along lines 5-5;
• each heat exchanger plate includes a plurality of undulatory pleats 12 having a wavy pattern in plan view designed to prevent nesting of the respective plates by causing the crowns or crests of each pleat to contact the crowns of the pleats formed in an adjacent heat exchanger plate.
• the side walls of each pleat subdivide the space between adjacent plates into a plurality of fluid flow passages to increase the total surface area actually contacted by the heat transfer fluids flowing between the heat exchanger plates.
• edge bars 14 are positioned at selected peripheral " positions between successive heat exchanger plates to direct the flow of heat exchange fluids through the heat exchanger and prevent commingling of the fluids while allowing heat transfer there ⁇ between.
• Inlet sections 15 and outlet sections 16 are attached to opposed sides of each heat exchanger plate to assist in directing the heat exchange fluids into the interplate spaces.
• the term "don ⁇ ative fluid” will refer to fluids capable of giving up heat energy within a heat exchanger and may in ⁇ clude either gas or liquid.
• the term “recipient fluid” will refer to any fluid, gas or liquid, which, when introduced into a heat exchanger, is capable of receiving heat energy from the donative fluid. In Fig.
• heat exchanger plates 2 and 4 are designed to define a recipient fluid flow chamber when the respective plates are positioned adjacent one another.
• a plurality of recipient fluid flow passages 18 are defined by adjacent side walls of the pleats 12 projecting into the recipient fluid flow chamber from plates 2 and 4.
• the space between plates 4 and 6 is designed to form a donative fluid flow chamber with the area between pleats 12 opening into the chamber forming a plurality of donative fluid flow passages 20.
• edge bars 14 and inlet and outlet sections 15 and 16 are arranged to cause the donative fluid to flow along the C-shaped flow path illustrated by arrow 22 within alternate spaced formed by the stacked plates while the recipient fluid is caused to flow in a reverse C-pattern illustrated by arrows 24 within the re ⁇ maining alternate spaces.
• an upper donative fluid flow passage forming blade is mounted for relative oscillatory movement with respect to a lower recipent fluid flow passage forming blade.
• the blades are designed to move between -a first position in which the blades are separated to receive an unpleated ductile sheet material and a second position in whioh the ductile sheet material has been deformed so as to form a ⁇ pleat side wall in the clearance space between the respective passage forming blades.
• Fig. 2 is a schematic cross-sectional illus ⁇ tration of pleating apparatus in which both the method and apparatus of the prior art as well as that of the present invention may be employed.
• First forming means 26 and second forming means 28 each carry an identical donative fluid passage forming blade 34 and 36, respectively.
• Third forming means 30 is positioned to cooperate with blade 34 in order to properly position the incoming ductile sheet material 37 and to form one side wall 38 of each pleat.
• Fourth forming means 32 supports a recipient fluid passage forming blade 40 adapted to enter the space between blades 34 and 36 as illustrated in Fig. 2, thereby causing a second side wall 42 to be formed in the clearance space between blades 34 and 40 and a third side wall 44 to be formed in the clearance space between blades 40 and 36.
• Fig. 3 illustrates the apparatus of Fig. 2 where ⁇ in first and second forming means 26 and 28 have been displaced upwardly to permit the ductile sheet material 37 to be displaced by a distance equal to the wavelength of the pleat wave in plan view in preparation for forming a successive pleat by forming means 26 through 32 all as described in greater detail in U.S. . Patent No * . 3,892,119.
• FIG. 4 a perspective view of prior art fluid passage forming blades of the type used in the apparatus of U.S. Patent No. 3,892,119 is shown including a pair of donative fluid flow passage forming blades 34' and 36' and a recipient fluid flow passage forming blades 40'.
• the prior art blades of Fig. 4 have uniform thicknesses.
• the apparatus of Fig. 2 will form pleats in ductile sheet material 37 having side walls of ir ⁇ regular slope, thus creating an unstable structure in which the side walls are easily distorted by outside mechanical force or temperature induced contractions and expansions.
• Fig. 4 a perspective view of prior art fluid passage forming blades of the type used in the apparatus of U.S. Patent No. 3,892,119 is shown including a pair of donative fluid flow passage forming blades 34' and 36' and a recipient fluid flow passage forming blades 40'.
• the prior art blades of Fig. 4 have uniform thicknesses.
• the apparatus of Fig. 2 will form pleats in
• FIG. 5 wherein a cross-sectional view taken along lines 5-5 of the apparatus of Fig. 2 is illustrated as the apparatus would appear if equipped with the prior art blades of Fig. 4.
• Fig. 5 illustrates dona- tive fluid passage forming blades 34' and 36' having a constant thickness d, and a pair of curvilinear side walls each of which consists of alternating circuar arcs arranged in a path which defines a periodic function.
• the recipient fluid passage forming blade 40' is also formed with a constant thickness d- and is provided with side walls which in cross section are each formed of successive cir ⁇ cular arcs which define a periodic function having the same phase and wavelength as the periodic func- tions defined by the surfaces of blades 34' and 36'.
• the clearance space between the blades in plan view regardless of the shape or configura- tion of the curvilinear pattern formed by the blade surfaces, cannot be constant. Even if the surfaces of each blade were formed by identical sine waves displaced laterally, the clearance spacing between the blade surfaces would still vary when the clear- ance is measured in a direction perpendicular to the central axis of the clearance space.
• the central axis between two curvilinear lines will be defined as the loci of all points located midway between the two curvi- linear lines as measured along a line normal to one of ⁇ the curvilinear lines at each point along such line. Obviously, this definition presupposes the absence of any discontinuities in the two curvilinear lines in order for there to be a continuous central axis.
• each donative fluid flow passage must be larger in cross-sectional area than is each of the recipient fluid flow passages.
• each wavelength portion W of blade 40' is constructed in a first section with side w *•alls which sweep out circular arcs having radii r, and r 2 with both arcs having a coincident center of curvature C, .
• the remaining portion of the wave- length section of blade 40 s ** is-similarly formed to provide blade surfaces having radii of curvature r,' and r 2 ' with a coincident center of curvature C 2 located on the opposite side of the blade.
• each wavelength portion of donative fluid forming passage blades 34' and 36' similarly includes surfaces which define circular arcs having radii of curvature R-, and R 2 with a coincident center of curvature C ⁇ .
• a second section of each wavelength portion of blades 34' and 36' has corresponding radii of curvature Ri' and R 2 ' with a coincident center of curvature C, located on an opposite side of blades 34' and 36' from center of curvature C 3 .
• OMPI the construction and reproduction of the heat ex ⁇ changer plate.
• the clearance between the blades varies from a maximum of M to a minimum of m.
• the minimum clearance m is normally made only slightly larger than the thickness of the plate material plus a small amount allowed for ease of withdrawing the blades of the pleating apparatus. This arrangement allows the greatest number of pleats per unit- length of plate as possible.
• lines 6-6 indicate a cross-section taken along a plane perpendicular to the central axis of blade 34' and thus lines s, in Fig. 6 are represen ⁇ tative of the slope of both side walls 38 and 42. As is apparent, the slope of these side walls is virtually perpendicular to the plan surface of the heat exchanger plate being pleated.
• Fig. 7 of a portion of a heat exchanger plate being formed by the assem ⁇ bly illustrated in Fig. 5 as taken along line 7-7.
• this varying slope of the pleat side walls 38 and 42 along the longitudinal extent of each pleat formed by the assembly of Fig. 5 results from variation in the clearance between the blade surfaces.
• Fig. 8 wherein a per ⁇ spective view is shown of the heat exchanger plate forming apparatus of the subject invention. As clearly illustrated in Fig.
• Fig. 9 is a cross-sectional view of the apparatus illustrated in Fig. 8 when positioned by the forming assembly, illustrated in Fig. 2 taken along lines 5-5.
• the don ⁇ ative fluid passage forming blades 34" and 36" are shown as having a substantial blade thickness vari ⁇ ation along the longitudinal extent of each blade from a minimum of P, to a maximum of P 2 «
• the recipient fluid passage forming blade 40" is provided with a uniform thickness as measured in the direction of a plane passing perpendicularly through the central axis of the blade in plan view along the entire longitudinal length of the central axis. Variations in the width of the donative fluid flow passages are significantly more acceptable in view of the substantial width of such passages as compared with the narrower cross-sectional width of the recipient fluid flow passages.
• the wavelength portion W of blades 34", 36" and 40" spanning between the lines marked w, and 2 can each be divided into a first arcuate section wherein the radii of curvature of the re ⁇ spective side walls of blade 40" are indicated by S, and S 2 , respectively.
• the adjacent surfaces of blades 34" and 36.” facing the corresponding surfaces of blades 40" are shown by arrows indicated at S 3 and S,, respectively.
• each of the circular arcs identified by arrows S, through S 4 are coincident at point SC.
• the remaining side surfaces of each of the blades 34", 36" and 40" form in plan view circular arcs touched by arrows Y, , Y 2 , Y, and Y. having a coincident center of curvature YC located on a side of blade 40" opposite to center of curvature SC.
• arrows 2 and S 2 complete a wavelength of the opposite side of blade 40".
• a full wavelength of the surface of blade 34" adjacent blade 40" is formed by circular arcs touched by arrows Y. and S ⁇ .
• a full wave length of the side of blade 36" adjacent blade 40" is formed by the circular arcs touched by arrows , and S ⁇ .
• the cross-sectional area of the recipient fluid flow passages formed by blade 40" will remain constant throughout their longitudinal length.
• the slope of all of the -side walls forming the pleats within the heat exchanger plate will remain uniformly constant and equal throughout the full longitudinal extent of each pleat.
• the side walls 42 and 44 similarly include wavelength sections W having concentric circular arc sections having radii of curvature corresponding to the radii S, through S, and Y, through Y..
• Fig. 10 a partial cross-sectional view of blades 34", 36" and 40" is illustrated as taken along lines 10-10 of Fig. 9 wherein the slopes of side walls 38, 42 and 44 are illustrated by lines 46, 48 and 50. As can be seen in Fig. 10, lines 46, 48 and 50 form an equal angle relative to a plane formed by the outer plan surfaces of the pleated heat exchanger plate.
• Fig. 11 similarly discloses a partial cross- sectional view of blades 34", 36" and 40" taken along lines 11-11 of Fig. 9. Note that the cross-sectional view of Fig. 11 has been taken at a point of maximum width of blade 34" as compared with the position of the cross-sectional view illustrated in Fig. 10 wherein the thickness of blade 34" is at a minimum. Despite this variation in the cross section width of blade 34", the slopes of side walls 38, 42 and 44 as represented by lines 52, 54 and 56 are iden ⁇ tical to the slopes of the corresponding lines 46, 48 and 50 of Fig. 9.
• the method and apparatus of forming a pleated heat exchanger plate as illustrated in Figs. 8-11 is capable of providing a heat exchanger plate wherein the recipient fluid flow passages include uniform and constant cross-sectional areas while the slope of the side walls of the pleats forming the respective fluid flow passages is constant throughout the entire long ⁇ itudinal extent of each fluid flow passage.
• a highly efficient, compact and rigid heat exchanger can be formed by stacking plural pleated heat exchanger plates of the type formed by the apparatus and method illustrated in Figs. 2, 8 and 9.
• Heat exchangers formed by the method and apparatus disclosed herein, as well as the heat exchanger plates designed in accordance with this invention, can be employed in a vast number of applications wherein the transfer of heat from one fluid to a second fluid is desired.
• the exhaust gases from a gas turbine may form the donative fluid for heating the compressed intake air leading to the combustor and then to the turbine whereby the intake air becomes the recipient fluid referred to above.
• a heat exchanger formed in accordance with the subject invention and including the pleated plates described above can be used in the boiler of a steam generation ' device wherein hot gases from fuel combustion forms the donative fluid while the recipient fluid is the return water or make-up water from which steam is to be generated in the heat exchanger.
• Still other applications include the use of a heat exchanger formed in accord ⁇ ance with the subject invention wherein the recipient fluid is the cooling water of an internal combustion engine and the donative fluid is the hot oil.
• Addi- tional applications include the use of heat exchangers of the subject type employed in heat treatment furnaces and other industrial applications wherein it is desired to transfer heat from one fluid to another.

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

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• 1981
  • 1981-02-18 DE DE8181901731T patent/DE3166239D1/de not_active Expired
  • 1981-02-18 WO PCT/US1981/000208 patent/WO1982002940A1/fr not_active Ceased
  • 1981-02-18 EP EP81901731A patent/EP0072797B1/fr not_active Expired
  • 1981-02-18 JP JP56502135A patent/JPS58500080A/ja active Pending
  • 1981-10-15 CA CA000387947A patent/CA1152977A/fr not_active Expired

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