Abstract: A heat exchange device is provided whose exchange zone is formed of a stack of perforated plates having perforations disposed so that superimposition of the perforations creates flow spaces for at least two fluids at different temperatures, said perforated plates being separated two by two by at least one seal disposed so that each perforation of the plates corresponding to a flow space through which fluid passes is separated from the perforations corresponding to the flow spaces through which a different fluid passes, said stack being kept at a clamping pressure of 2 to 50 bars by means of a plurality of tie-rods passing through it and said seal being formed by an expanded graphite manufactured under such conditions that it has a bulk density of about 200 to 500 kg.m.sup.-3.

Abstract: An improvement applicable to a plate type heat exchanger for the purpose to make the fabrication thereof easier and to improve the strength and airtightness thereof.

Abstract: A heat exchanger for use for example in a laundry dryer comprises a plurality of plates defining flow passages therebetween for a first heat exchange medium. Each plate is made up of a plurality of aluminum elements having mutually co-operating positive and negative profilings at their narrow sides, to fit snugly together. The plates are held at a spacing from each other in grooves in end wall members forming a holding assembly. A second heat exchange medium flows through the hollow interiors of the elements making up the plates. The hollow interiors have web portions therein, to enhance heat flow between the first and second heat exchange media.

Abstract: A heat exchanger for two fluids, especially an oil cooler for oil and water in an internal combustion engine. The heat exchanger is made up of a dividing wall having a meander-like cross section which is bounded by two side covers to form longitudinal channels and having a headering system comprising cross channels, connecting channels, feed channels, and inlet and outlet openings located at each end of the heat exchanger. The heat exchanger is of modular design so that it can be easily expanded by the connection of several heat exchanger units.

Abstract: An improved heat exchanger is shown for indirect heat exchange between two fluid media. The heat exchanger has thin metallic walls and a multitude of convoluted shaped internal flow passages, increasing the effective contact time during which heat is transferred between the media. The heat exchanger is particularly suitable for heat exchange between fluids having low differential temperatures or specific heats, due to the thin wall structure, the elongated internal flow path created by the convoluted core structure and the absence of welds, soldering, or other thick areas which tend to inhibit heat transfer due to their relatively greater mass. The heat exchanger may be produced by a novel technique. A support matrix is assembled from a plurality of low melting point forms, each of which has angled internal passages. The passages of each form are positioned in register with the passages of adjacent forms.

Abstract: A heat exchanger unit comprising a particulate heat exchanging mass or pack consisting of relatively small, mechanically immobilized particles having a thermal diffusivity constant of at least 0.5 cm.sup.2 /sec at 20.degree. C., and compressively retained in an enclosure in heat transfer relationship to each other and to a fluid directed therethrough. Preferred materials for the particles are crystalline carbon, copper and aluminum. The pack may be in cylindrical form or planar form and may be contained within metal conduits or, for solar radiation, within a transparent or translucent enclosure. Interconnected units may be disposed in an array or bank to provide the desired quantitive degree of thermal transfer.

Abstract: The invention relates to a heat exchanger for use as a reboiler-condenser which increases the efficiency of heat transfer between boiling and condensing fluids such as cryogens, e.g. oxygen and nitrogen in an air separation unit. The exchanger has enhanced boiling and condensing surfaces and slightly inclined condensing passages built up from individually extruded passageway elements.

Abstract: A heat exchanger for use in industries concerned with utilizing corrosive or abrasive fluids, either at low or high temperatures, is made of a monolithic body molded from refractory material and includes at least one channel for the fluid to be heated and at least one channel for the fluid to be cooled, these channels being integrally molded and in a mutual heat-exchange relationship.

Abstract: A heat exchanger unit comprises a support on which is positioned a plurality of stays mounted at spaced locations. A horizontally extending bracket is secured to each of the stays and a plurality of connected heat exchanger plates are suspended from their upper ends from the brackets. The plates have heat media carrying channels which are joined together. The support advantageously comprises a steel ring to which the brackets are attached and which extend radially inwardly also radially outwardly. The heat exchanger plates are rectangularly shaped and are suspended from each bracket so that it hangs freely downwardly. Wire guards extend between the plates to prevent them from deflecting and contacting each other. The construction permits the elimination of spaced support elements which interfere with free heat exchange flow between the plates.

Abstract: A gas-tight crossflow heat exchanger consisting of a metal casing with two gas inlet nozzles and two gas outlet nozzles, at least one installation cover on the top of the casing, a block consisting of a number of ceramic heat-exchange elements mounted completely accurately in cuboid form with gas ducts arranged in layers one above the other and running at right angles to each other, four side surfaces having gas-duct openings, and the bottom and top surfaces being free of openings, the heat exchanger further consisting of thermal insulation between the metal casing and the block of ceramic heat-exchange elements.

Abstract: A recuperative or restorative spiral heat exchanger with separating walls spirally extending between fluid streams of medium having an exploitable temperature gradient. Each two adjacent separating walls enclose between themselves a flow duct for one of the two streams of medium and the spiral space between two flow ducts forms the path of flow for the other stream of medium. The spiral is provided in the form of a multiple or multi-channel spiral by arranging a plurality of flow ducts. In particular, the spiral heat exchanger consists of two multiple spirals with opposed directions of current.

Abstract: The heat exchanger designed, for example, for cooling highly viscous, especially intrinsically viscous free-flowing substances is provided with cooling elements (1) consisting of flat tubes which are built into a straight flow-through area (4) for the free-flowing substance to be cooled. In order to make possible a heat exchanger for intrinsically viscous, free-flowing substances which is as compact as possible, yet very effective, the cooling tubes (1) are arranged in spaced, adjacent rows in parallel planes which run obliquely to the direction of flow (X) of the heat exchanger and are at a distance from each other in the direction of flow of the heat exchanger. The cooling elements (2, 3) arranged in two adjacent planes intersect each other, viewed in the direction of flow of the heat exchanger, at an angle of 90.degree..

Abstract: A heat exchange device comprises at least one zone for the circulation of at least two fluids in heat exchange relationship and input and output means for these fluids, the zone being of modular structure and consisting essentially of a stacking of lattices jointly assembled and each formed of two series of intercrossed walls. The stacking of lattices define spaces for the circulation of the fluids, each lattice, which constitutes a module, being formed in one piece and so designed that, on each face thereof, the edges of the walls of one of the two series are protruding from the plane formed by the edges of the walls of the other series. The lattice stacking is achieved by registering the protruding edges of a series of walls of one face of any lattice with the recessed edges of the corresponding wall series on the opposite face of the adjacent lattice. The protrusion height is equal to the depth of the registering recess in the lattice stacking.

Abstract: A heat exchanger capable of use as a counter-flow heat exchanger comprises a series of conduits for a first fluid, the conduits being arranged in panels that are spaced apart. The intervening spaces are traversed by a second fluid, and surface-extending elements are located in such spaces, each surface-extending element comprising a sheet from which portions have been pressed out to define a number of knuckles that are located in heat-transmitting contact with a conduit panel on one side of the space. At least some of the knuckles may be secured to the conduit panel.

Abstract: The heat exchanger consisting of a stack, forms a right prism, of polygonal plates with perforations of elongate shape. The rows of perforations are stacked and each perforation of a plate communicates with two perforations of the following plate, thereby forming series of independent networks of interconnected perforations. Two systems of networks are thus provided, each of which is used to circulate a fluid. Supply and discharge means are also provided for each of the fluids.

Abstract: A heat exchanger of modular structure comprises stacked lattices which can engage with each other, and each is formed of two series of intercrossed small plates jointly assembled by mutual engagement at the level of cuts located on the edges of the plates, with spaces being generated for circulating fluids therethrough in heat exchange relationship.

Abstract: A two-circuit heat exchanger is characterized in that the heat exchange tube(s) of each circuit is/are formed with non-circular cross-section to exhibit at least partially plane side surfaces, said side surfaces of the tubes in the two circuits being in heat-exchange relationship with one another.

Abstract: Ceramic honeycomb type recuperative heat exchangers having a large number of parallel channels formed of partition walls are disclosed, in which fluids to be heat-exchanged are passed through respective channels that are produced by extruding a ceramic raw batch material into a honeycomb structural body, drying the shaped honeycomb structural body, prior to or after firing step cutting off partition walls in the given rows of the honeycomb structural body in the axial direction of the channels to a given depth from the end surface of the honeycomb structural body and sealing only the end surfaces of said rows.

Abstract: A compact heat exchanger and method for making the same using the interior of randomly arranged interconnecting hollow spheres as a conduit for a first fluid and the exterior of same as a conduit for a second fluid of different temperature. The apparatus is constructed by fusing the points of contact between the objects of a packed cluster of objects, forming an impermeable layer on the fused objects and removing the fused objects to leave hollow shells interconnected at their points of contact. The interconnecting interiors of the hollow shells form an inner space to which fluid entry and exit ports may be provided to entry and exit manifolds. An outer interstitial space is realized by channeling the second fluid through the porosity in the cluster of shells comprised of the spaces outside the interconnected hollow shells.

Abstract: A multi-shell heat exchanger is disclosed in the preferred embodiment comprising at least two interconnected spherical shells wherein one shell encloses the other. Tubular connectors connect the shells in spaced relation defining an annular space between the shells for a circulating cooling fluid. A second fluid passage through the shells provides a continuous separate flow path for a circulating fluid to be cooled.

Abstract: The invention relates to a heat exchanger for an electronics cabinet with a folded surface profile in which, alternatingly on both faces every other fold is closed off gastight or dustproof by a cross cover. With such an air/air heat exchanger the waste heat from the interior of an electronics cabinet can be dissipated to the outside when the electronics cabinet is closed dusttight. To facilitate production of the folded surface profile, the cross covers are integrally formed onto the folds. Such a folded surface profile, in which the folds and the cross covers form one integral component, is preferably produced as a deepdrawn part, so it is possible to make the component from plastic. In another embodiment, the folded surface profile can be a plastic injection molding.

Abstract: A devolatizing heat exchanger having an annular body with an open end and a closed end. Axially extending heat exchange fluid conduits are axially disposed and radial product conduits are disposed in the annular body. A mixing chamber is enclosed within the annular heat exchanger discharging adjacent the closed end thereof, the annular heat exchanger being enclosed within a jacketed vessel.

Abstract: A parallel plate air-to-air counterflow heat exchanger employs a parallel array of spaced plates of similar elongated hexagonal shape. A pair of inlet and outlet ducts is connected to each lengthwise pointed end of the array. Each duct communicates with alternate airways via rectangular openings staggered on opposite sides of the ends of the array. The ducts extend parallel to a lengthwise midline of the array to enable air flow through the heat exchanger and ducts with minimal change of momentum and turbulence. The plates each have parallel widthwise margins which are oppositely rolled to different, complementary radii and adjacent plates are mutual mirror images. The plate margins nest together to interconnect the plates and enclose one side of each airway. A housing around the array encloses the opposite side of each airway.

Abstract: A heat recuperator comprises a monolithic refractory block containing a first array of waste gas passages and a second array of combustion air passage segments oriented perpendicular to the waste gas passages. At least one turnaround manifold interconnects successive combustion air passage segments into multiple-pass passages. Preferably waste gas passages are tapered from a larger area entry aperture to a smaller area exit aperture. Successive combustion air segments are preferably tapered in opposite directions in the refractory block so that they can be interconnected to form a multiple pass passage with a substantially continuous taper from a smaller area initial entry aperture to a larger area exit aperture. The monolithic refractory block containing integral passages can be formed in a single casting or ramming operation.

Abstract: A holding tank receives waste water from a dishwasher or laundry machine having a rinse cycle and at least one wash cycle. A pump moves the waste water through a heat exchanger at the same time that the rinse cycle requires hot water from a hot water heater. The cold water feed for the hot water heater is also passed in countercurrent heat exchange relationship with the waste water to provide warmed or heated makeup water at the same time that hot water is being withdrawn therefrom. The cooled waste water from the heat exchanger may be collected in a tank and supplied to any one or more of several additional devices, such as a water cooled refrigerant compressor, a grease extraction ventilator having water contact means, a waste food grinder, etc. The ventilator and compressor may also be placed in series, while the cooling water heated in the compressor is recirculated to the heat exchanger.

Abstract: Process and apparatus for manufacturing heat exchangers from ceramic sheets, wherein different flow channels are stamped from or pressed into the sheets, and the formed sheets are joined together with a laminating agent. The stacking of the individual sheets is effected using apparatus in which the sheets are transported to the forming means, applicator means and laminating means by horizontally and vertically displaceable, rotatable and pivotable suction plates. The organic component of the ceramic sheets is expelled from the heat exchanger block obtained in two heating steps with an intermediate forming operation to bring the heat exchanger block to its final dimensions, and the block then fired between 1,200.degree. to 1,700.degree. C. The actual sintering temperature depends on the particular ceramic used, which may comprise Si.sub.3 N.sub.4, SiC, cordierite and/or semiconductive barium titanate compounds.

Abstract: A cross flow heat exchanger is provided comprising a longitudinal duct housing and a heat exchange element positioned offset and diagonally in two planes therein. This design permits air to be introduced to the heat exchanger element through a tapered converging plenum, so that air is efficiently introduced into the said heat exchanger element, and to exit said heat exchanger element through a diverging reverse tapered plenum.

Abstract: A constant temperature element for heating or cooling a working gas to the temperature of a control fluid is disclosed. The element includes a plurality of hollow concentric tapered rings of conductive material having a serrate configuration in section with tips projecting into the working fluid. A plate is typically attached to and generally flush with the base of the rings except for a central elongate plenum spanning the rings and having inlet and outlet ends respectively and a barrier at the center. The temperature control fluid enters at the inlet of the plenum so that it circulates through the rings and exits through the outlet of the plenum to maintain the rings, and thereby the working fluid adjacent the rings, at the temperature of the temperature control fluid.

Abstract: A heat recuperator comprises a cross-flow ceramic core within a housing. The housing includes an inlet conduit and an outlet conduit for a gas to be heated. The housing also includes means for thrice passing said gas through the ceramic core in order to improve the diffusion of the gas through the core.

Abstract: A heat exchanger for energy efficient ventilation of buildings is described. The heat exchanger has a core structure defined by a plurality of rectangular sheets of an extruded, cellular plastic material disposed in parallel, spaced-apart relationship. The cells of the sheets provide a first set of flow paths extending between ends of the core structure for use in passing cold fresh air. The spaces between the sheets are sealed at each end of the core structure, and a cellular plastic sealing material is wrapped about the sides, top and bottom of the core structure and apertured at opposite ends to access the spaces, so that the spaces between the sheets define a second set of flow paths for passing stale warm air. A drainage aperture is provided in an inner face of a bottom sheets of the sealing sheet, where condensation tends to accumulate. The drainage aperture permits condensation to escape through the cells of the bottom sheet.

Abstract: A method of producing multiple coil, multiple tube heat exchanger from circular tubes, in which alternating turns in each coil have a warmer liquid and other turns a cooler liquid, by coating the outside of each coil with a heat conductive mastic and winding the next coil against the mastic to force the mastic into spaces between adjoining tubes of the first coil, into spaces of adjoining tubes of the second coil and into spaces between opposed tubes of first and second coils. Mastic applied to outside of each coli or into grooves between turns as next coil wound. Double tubes of each coil preferably wound into grooves between turns of preceding coil. Second tube of each coil started across coil from first tube and continued at end of coil past first tube. Succeeding coils wound against mastic in same manner. Turns of first coil attached together, as by soldering, while first and last turns of succeeding coils similarly attached to adjacent turn of coil beneath.

Abstract: The specification discloses a heat exchanger of particular construction and methods of using same, the exchanger having pairs of sealing elements through which a circulating fluid is passed. The circulating fluid can be used for leak detection, cooling, or sterilization. The exchanger has a plurality of coaxially arranged tubes of thermally conductive material, the tubes being spaced apart radially by a pair of end manifolds to form annular fluid flow passages at least one of the manifolds having first and second sealing elements for forming seals between the manifold and the ends of the tubes, circumferential fluid passages being defined between the first and second sealing elements, circulating fluid inlet means for admitting a circulating fluid at first locations in the passages, and circulating fluid outlet means for discharge of said circulating fluid at second locations in said passages, the first and second locations being circumferentially spaced for each passage.

Abstract: The present invention relates to a laminated heat exchanger having a laminated construction consisting of a plurality of perforated heat transfer plates and spacers arranged alternatingly, the spacers defining a plurality of fluid passages between respective adjacent heat transfer plates, so that heat is exchanged between different fluids flowing in different fluid passages through the heat transfer across the heat transfer plates. More specifically, the invention is concerned with a heat exchanger of the type described above, wherein a plurality of separate scroll passages are formed by the spacer, so that local concentration of each fluid in its passage is avoided to remarkably improve the heat transfer efficiency.

Abstract: A heat exchanger within a dense gravity layer comprises a vertical cylindrical container with a heating surface built thereinto. The heating surface is formed by a tubular housing containing a plurality of tubes mounted in tiers. A space between the inner surface of the container and the outer surface of the housing is divided by opposite seals into two vertical cavities. These cavities are divided along the height thereof by horizontal baffle members which are arranged in chessboard pattern relative one another to form chambers located along the height in a chessboard pattern, and to accomplish repeated variation of the direction of movement of one of heat carriers.

Abstract: A compact heat exchanger suitable for use in an automotive exhaust gas recirculation system. It has two interconnected elongated cooling chambers supported within a two piece outer casing. The fluid to be cooled enters the first cooling chamber at an intermediate location, flows towards opposite ends of the chamber then out of the first chamber into the ends of a second chamber through connecting passageways and finally towards an outlet located intermediate the ends of the second chamber. The cooling fluid enters the outer casing at one end flows over and along one side of the first chamber then through an aperture in a flange that divides the casing into two compartments. From this aperture it flows along and over both sides of the second chamber and one side of the first chamber to an outlet located at the same end as the coolant inlet. The component parts are designed to be assembled in a foolproof manner and copper brazed together with relative ease.

Abstract: A thin metal heat exchanger having countercurrent flow of media on opposite sides of spaced walls is disclosed. The walls are configured with ridge-depression shapes extending at an angle to the direction of flow of media on opposite sides of the plate so as to create circulation but not turbulence of the flowing media in the depressions.

Abstract: A heat exchanger including the multiplicity of elongate laterally spaced parallel tubes, each of which is formed with circumferentially spaced longitudinally extending radially outwardly projecting lobes which are semi-circular in cross-section and circumferentially spaced longitudinally extending radially outwardly opening intermediate grooves which are semi-circular in cross-section and wherein related lobes and grooves of adjacent tubes are interengated with their opposing semi-circular surfaces in uniform spaced relationship from each other whereby a labyrinth of passages of substantially uniform cross-section, through which a fluid medium can flow, occur about and between all adjacent related tubes whereby more uniform lateral flow of a fluid medium about and between adjacent tubes is attainable.

Abstract: A cast metal heat exchanger (e.g. of iron or aluminum) for a hot water boiler having a plurality of flueways and waterways and which is rectangular in plan view down onto the flueways with the waterways extending parallel to the minor rectangular axis. A method of manufacturing a cast metal waterway section of cuboid volume less than 4500 mls for a heat exchanger (which comprises casting the metal into a mould with the waterway core vertically disposed. A heat exchanger comprising a plurality of such sections can be formed integrally by vertically casting such a plurality simultaneously in one mould.

Abstract: An intermeshing passage manifold is a device for subdividing each of two passages of ducts connected to it into multiple adjacent separate intermeshed passages. The intermeshing passage manifold is to be used for heat exchangers and fluid mixing devices in order to minimize pressure (energy) losses and to satisfy geometric constraints in many applications. The intermeshing passage manifold consists of a number of manifold sections adjacent in an end-to-end manner. Each of the manifold sections consists of a number of passage modules adjacent in a side-by-side manner. Each passage module consists of two passages; the orientation of these passages at one end of a module is at right angles to the orientation of the passages at the other end of the module, however, the cross-section shape of the module remains the same throughout its length.

Abstract: A reactor and the use thereof for fueling an internal combustion engine.The reactor comprising a monolithic substrate and catalytic material,said monolithic substrate containing a plurality of substantially parallel channels, means being provided for charging a heat exchange fluid into said channels and recovering said heat exchange fluid from said channels, said monolithic substrate containing a plurality of passageways through said substrate generally parallel to said channels, said passageways being adapted to pass a reactant stream through said monolithic substrate and said passageways being larger in cross section and fewer in number than said channels, said catalytic material being supported within said passageways, as a coating on the passageway walls or as pellets.

Abstract: A heat exchanger composed of stacked perforated sheets forming two series of channels for at least two fluids, with a hot fluid and a cold fluid, the heat being transferred through the sheets. A distribution system is provided at each end and includes (a) a series of grooves communicating with an external duct, and (b) passages passing throughout a distribution plate and communicating with an external duct.

Abstract: In a reactor consisting essentially of a monolithic substrate containing a plurality of substantially parallel channels having catalytic surfaces and means for charging a reactant stream into the channels and recovering a product stream from the channels, an improvement comprising; positioning a plurality of passageways through the monolithic substrate generally parallel to the channels with the passageways being adapted to pass a heat exchange fluid through the monolithic substrate.

Abstract: The invention relates to a plate heat exchanger, which comprises a plurality of plates (1) arranged to the side of each other, each plate consisting of two metal sheets (2,3), which are welded one to the other along two parallel edges and have longitudinal bulgings in parallel with said edges. The invention has the object to produce a plate heat exchanger where the medium flowing within the plate is guided in a direction in parallel with the extension of the bulgings and back in the same direction. Each plate (1) is formed with a turning zone in that the bulgings in pairs meet in such a manner, that in the sheet plane two outermost bulgings meet along a semicircle line, thereafter the two bulgings next to the outermost ones, a.s.o., and the number of bulgings is an integer number.

Abstract: An electrical resistance water heating device, particularly intended for use in coffee or other beverage preparation machines, includes a solid metal heating plate having planar upper and lower surfaces. A fluid throughflow duct is formed between the upper and lower surfaces and includes at least two elongated, spaced, side-by-side branches having corresponding ends interconnected by a connecting conduit to form a continuous fluid flow path from a water inlet to a water outlet. An elongated slot is formed between each pair of side-by-side branches and at least one plate-shaped planar PTC heating element is accomodated within each elongated slot with each of the opposing surfaces thereof directed toward a respective one of the pair of side-by-side branches between which the duct is formed. The spaces between the heating element and walls of the slot are filled with a hardenable electrically insulative filling of good heat conductivity.

Abstract: The invention relates to a static cylindrical monolithic cellular structure with a large contact area, said structure being used in particular for a static heat exchanger and including a plurality of parallel ducts. Its general organization is essentially cylindrical, and the ducts are defined by radial walls (10) and circumferential walls (11). Said ducts form groups for conveying different fluids with the groups being in an essentially radial configuration, i.e, with groups for conveying different fluids at least some of the radial type walls constituting the boundaries between different fluid flows. Application in particular to static exchangers and to filters.

Abstract: A first water header is connected to a second water header by laterally-spaced multiple parallel composite tubes, each consisting of two or more component tubes of vertically-elongated rectangular cross-section welded to one another along their horizontal narrower adjoining faces, the height of each component tube being a multiplicity of times the width thereof. The thus welded faces form intermediate partitions or webs of doubled thickness running the entire length of the composite tube. This greatly strengthens the composite tube thus obtained and also divides the cooling water flow into vertically-spaced thin streams or bands of cooling liquid. Rising from the first and second headers are first and second fittings which serve not only to transmit the cooling water into and out of their respective headers but also serve to connect and attach the header to the keel or other underwater location of the heat exchanger to the hull of the boat or vessel.

Abstract: A low profile heat exchanger module (46) and method for forming the same wherein the heat exchanger module (46) is formed from one or more compact, single sheet primary surface heat exchanger core units (38a and 38b). Each single sheet primary surface core unit (38a and 38b) is made from a rectangular sheet of a suitable heat exchange material (10) which has been serrated along the longitudinal edges (18) to provide entrance ramps (20) and to minimize flow blockage. Fluid flow is controlled by closures (42, 44) in the ends of alternate flow passages (58, 64) which serve to isolate the fluid in one passage from the fluid in an adjacent passage.

Abstract: The invention provides a protective casing for a cube-shaped modular ceramic heat exchanger core, in which the core can easily be installed without danger of leakage between the fluid paths of the core. To this end the core rests in the casing with the edges of one face engaged with a suitable ceramic fibre composition gasket; the opposite face of the same flow path is engaged by another such gasket and the gasket is in turn engaged by a gasket compression member. The compression member is urged into this engagement by strong springs which thereby hold the gaskets in the necessary sealing engagement. In one aspect of the invention the casing is readily changed to provide single or multi-pass of one of the flow paths through the core; such a casing consists of a central portion of the thickness dimension of the core and replaceable end portions which provide the inlet, outlet and respective plenums.

Abstract: The invention relates to a recuperative heat exchanger comprising an elongate rotationally symmetric body of ceramic material having radially outwardly extending, flow channels of slot like cross-section extending along the axis of the body. Alternate flow channels extend further toward the surface of the body and further toward the axis of the body, respectively. Inlet and outlet openings are provided for the flow channels about at the ends of the body. The invention also comprises a process for making such a heat exchanger, including extruding ceramic material through an extrusion nozzle with a free cross-section in which core bodies are shaped and positioned for generating the flow channels and inner and outer cover walls defining the flow channels. The invention further comprises the extrusion nozzle in which the process is performed.

Abstract: A pipe spiral bundle for a heat exchanger is produced by using pre-fabricated pipe spirals of the same shape, each pipe spirals having pipe loops essentially in one plane and at distances inside each other, such spirals being arranged concentrically and directly on top of each other and then tightly attached to each other so as to form a continuous spiral-shaped contact line between adjacent spirals, and a mutual branch pipe being connected to one end of each pipe spiral and a mutual collector pipe being connected to the opposite end of each pipe spiral. The pipe spirals may be heat welded to each other or connected to each other by mechanical binding members, such as metal bands.