Abstract: The flow control device for a steam circulating heat exchanger tube (2) comprises an insert (4), secured in the tube by expansion in a zone (9) near the end of the exchanger tube or of the tube sheet (1) orifice provided in lieu of said tube, and an orifice plate (7) made from an erosion-corrosion resistant metal and secured inside the insert upstream from the bulged zone (9) created by expansion, from the standpoint of fluid flow, said insert extending for a considerable length downstream from the orifice plate. The insert includes an upstream tubular member (5) made from a metal having a low yield strength but a high elastic elongation ratio and a downstream tubular member (6) made from a metal resistant to erosion-corrosion and at least as long as ten times its inside diameter, ending in a bevel (12) tapering outwardly at an angle of less than 15.degree..

Abstract: A turbulator for insertion in a heat exchange pipe in the form of a flattened hollow cylindrical metal tube with adjacent flats offset by 90.degree. and separated by integral tubular transition portions of generally triangular plane configuration. An elongated tab is partially struck out of each flat forming a fluid passage hole leading from one side of the turbulator to the other side.

Abstract: An orifice insert for placement in nuclear steam generator tubes comprises a sleeve having a top end, a bottom end located in use in the vicinity of the opening of the steam generator tube, and a longitudinal axis. An orifice is disposed in and extends the entire length of the sleeve. At least a portion of the outer diameter of the sleeve is substantially the same as the inner diameter of the steam generator tube. The orifice comprises at least a lower and an upper cylindrical portion which are coaxial with the longitudinal axis of the sleeve, wherein the diameter of the upper cylindrical portion is smaller than the diameter of the lower cylindrical portion.

Abstract: A device for fixing a perforated sheet (8) against the perforated tube plate (1) of a heat exchanger having a bundle of tubes (4, 5), the perforated sheet (8) controlling the rate of fluid flow along the tubes, and the device comprising hollow pins (10) inserted in the ends of some of the tubes (4) and expanded therein, the hollow pins terminating outside the tubes with threaded ends (12) onto which respective nuts (15) are screwed for clamping the perforated sheet against the perforated tube plate, the nuts having heads including respective axial fluid-flow controlling bores (17).

Abstract: An angle duct for connecting, through a curved elbow section, a turbocharged engine charge cooler with oblong ends with a turbocompressor outlet or a manifold inlet having compact cross sections. The duct has tapered diffusing or expanding end sections enlarged in cross section and increasingly oblong toward the cooler joined by the flattened elbow section having constant or similarly increasing cross section. The combination in an engine induction system combines efficient flow diffusion and/or expansion together with low loss flow through the elbow and good distribution of fluid flow over the charge cooler inlet area.

Abstract: An eddy current brake has a particular cooling system which alleviates overheating of the brake and its individual components. Cooling conduits comprising a plurality of parallel flow lines are disposed close to the heated components and the arrangement is such that heat is uniformly exchanged and removed from the brake. Cooling medium flows through the conduits along the plurality of flow lines and the distribution of cooling medium is such that the velocity of flow is substantially equal along each line.

Abstract: A steam generator feed water heater comprises a pressurized enclosure inside which is a heat exchanger through which the feed water is caused to flow. There is at least one horizontal condensate inlet tube, as well as at least one condensate outlet tube at a low point on the enclosure. A double screen device associated with the condensate inlet tube comprises an inner screen with a cylindrical side wall and, surrounding this inner screen, an outer screen having one end linked to the inner screen. A bottom wall common to both screens constitutes an impact wall facing the inner screen. Passage areas are provided by perforations in the screens not facing each other over most of the perimeter of their transverse cross-sections.

Abstract: The invention provides fluid handling apparatus which may be heat exchange apparatus or fluid reaction apparatus. The apparatus is provided with an interrupter structure for disrupting the fluid boundary layers at the walls of the apparatus and promoting mixing of the separated boundary layers with the adjacent core layers. One interrupter structure comprises a plurality of longitudinally-spaced interrupter elements mounted on a core rod, each element comprising a plurality of blade-like members each of at least approximately spherical segment profile in side elevation, the members extending mutually radially outward relative to one another to touch or nearly touch the said surface or surfaces adjacent the elements. The elements are spaced longitudinally from one another the distance required to provide wake interference flow of the fluid, wherein the vortex upstream of one element cooperates with the vortex downstream of the next element in the fluid path.

Abstract: A plate-type heat exchanger wherein a plurality of flat plates are stacked in face-to-face relationship and diffusion bonded together. The plates are formed within their respective thicknesses with channels forming heat-exchange zones through which fluid passes to exchange heat with fluid passing through channels in adjacent plates. Each of the channelled plates has an inlet port which communicates with one end of the heat-exchange zone, an outlet port which communicates with the other end of the heat-exchange zone and, located between the respective ports and the associated ends of the heat exchange zone, a smoothing zone and a distribution zone. The smoothing zone comprises transverse fluid-flow passages wherein a transverse-flow component is imparted to fluid flowing between the distribution zone and the heat-exchange zone, and the distribution-zone comprises a plurality of fluid-flow passages extending between the port and the smoothing zone.

Abstract: A tube-and shell double-pipe or liquid-air fin type heat exchanger, which offers a high level of thermal energy transfer efficiency, incorporates a rotary blade to disrupt a fluid film on surfaces of each tube, and is of uncomplicated design and construction. The blade is free-floating and operates regardless of the direction of flow of the liquid through the tubes.

Abstract: The disclosed invention relates to a counterflow type heat exchanger composed of plural heat exchange units characterized by unique inlet and outlet headers. Each header has an end face providing an opening to the header interior and a closed end face, both of which extend obliquely from the tube sheet to join at an apex and which are symmetrically arranged with respect to each other. Such a construction enables the flow of fluid passing through each heat exchange unit to be uniform across the width of the heat exchange unit.

Abstract: A reheater for a steam power plant generally comprises a tube plate, a header including a high-temperature chamber and a low-temperature chamber defined outwardly of the tube plate, and a number of heat-exchanger tubes bent into U-shapes, both ends of which are secured to the tube plate. The reheater further comprises nozzle members, each having a flange portion, inserted into the upstream ends of the heat-exchanger tubes, respectively, and a bellmouth plate having a number of holes, secured detachably to the tube plate such that the holes align with the nozzle members. The flange portions of the nozzle members are secured firmly between the bellmouth plate and the tube plate.

Abstract: A heat exchanger has upper and lower plenums which communicate with each other via heat transfer tubes. A downwardly-extending tube used to introduce secondary sodium coolant into the lower plenum extends among the heat transfer tubes and is fastened to the lower tube plate to communicate with the lower plenum. The downwardly-extending tube is stretched through the lower plenum in the axial direction thereof to contact at its lower end a bottom surface of the heat exchanger body. A plurality of openings are provided in a wall of the portion of the downwardly-extending tube which is in the lower plenum.Primary sodium coolant of a high temperature flows into the heat exchanger body from the portion thereof which is below an upper tube plate, and flows out of the heat exchanger body from the portion thereof which is above the lower tube plate.

Abstract: A heat exchanger assembly comprises a plate-shaped heat exchanger having a plurality of flow channels each having an inlet end through which heat transferring fluid is introduced for passing through the flow channels in a flow direction and an inlet chamber into which the inlet ends of the flow channels open. The heat exchanger assembly further has a flow distributing flat nozzle situated in the inlet chamber of the heat exchanger. The nozzle has an outlet end oriented towards the flow channels and directly connected with the inlet end of the flow channels and an inlet nipple defining a tubular conduit. The flat nozzle defines a distributor chamber which is in communication with the tubular conduit and with the outlet end.

Abstract: Shell and tube heat transfer apparatus and a corresponding process of heat transfer employ a fluid flow consisting of non-turbulent boundary-layers adjacent the inner and outer heat exchanger surfaces of the tubes and a non-turbulent core-layer between the boundary-layers and interfacing therewith. Interrupter-structures disposed within the tube and shell flow passes and interrupt the full development of the boundary-layers at a multitude of spaced spots, leaving the heat transfer surfaces unaltered, unmodified and uninterrupted, so that the boundary-layers cannot increase in thickness but will partially separate from the surfaces and mix non-turbulently with the core-layer to effect the required heat transfer between the surfaces and the fluid. The interrupter-structure preferably consists of a plurality of rows of spheres, with which the space remote from the heat exchange surface is filled with a space-filling material to prevent the useless flow of fluid in a space not effective for heat transfer.

Abstract: Plate heat exchanger having mainly rectangular plates mounted in a frame. According to the invention the plates (6, 8) are arranged in at least two groups, the plates having port holes of one size being arranged in one group, while plates having port holes of another size are arranged in another group, the plate group having the largest port holes being arranged closest to the inlet (3) while a plate group having smaller port holes (9) is arranged further away from the inlet (3).

Abstract: A high efficiency fireplace with effective heat recovery capability for heating purposes and for heat storage. A fireplace boiler made of interconnected heat exchanger elements using sheet metal stamping technology, preferably corrugated metal stamped panels defining a plurality of water flow paths for circulating heat exchanging water. A wood burning domestic heating system using such an improved fireplace is also disclosed with suitable temperature control devices and thermal energy storage systems.

Abstract: A heat exchanger for a combustion unit having particular use with a water heater. The heat exchanger includes a plurality of generally parallel tubes disposed in a water heater tank in contact with the water to be heated and waste gases of combustion pass through the heat exchanger tubes. A turbulator is disposed in each tube to increase the heat transfer from the waste gases to the water in the tank. Each turbulator is formed from a generally flat strip of metal and has a plurality of transverse slits that extend more than one-half the width of the strip and terminate at a base. Generally triangular portions or tabs bordering each slit are bent outwardly and the tabs are disposed generally normal to the strip. One tab bordering each slit extends laterally from one side of the strip, while the other tab bordering that slit extends laterally from the opposite side of the strip. The end portion of the strip is bent about the base of a slit to position the end portion at an angle of about 30.degree.

Abstract: A flow control device for providing a substantially uniform and vortex-free inflow and distribution of feedwater to a steam generator having a tube bundle for a primary fluid disposed in a shell provided in the feedwater inlet nozzle including a diffuser structure, with a number of diffuser channels adapted to restrict outflow of water from the generator shell during a break in a feedwater pipe connected to the inlet nozzle and baffle means associated with said diffuser structure to deflect the feedwater flow in a radial direction about the inlet nozzle, the baffle means being arranged closely adjacent the inlet nozzle between the downstream ends of the diffuser channels and the tube bundle enclosed by the shell.

Abstract: A tube-and shell double-pipe or liquid-air fin type heat exchanger, which offers a high level of thermal energy transfer efficiency, incorporates a rotary blade to disrupt a fluid film on surfaces of each tube, and is of uncomplicated design and construction. The blade is free-floating and operates regardless of the direction of flow of the liquid through the tubes.

Abstract: An arrangement for exchanging heat between the environment and a heat-transfer fluid, especially a solar heat absorber, includes a plurality of heat exchange elements which are provided with external fins and have internal flow-through passages for the fluid. The heat exchange elements are mounted on and the passages thereof communicate with internal channels of collector pipes. The collector pipes are, in turn, connected by respective corner members to connecting pipes to form a frame therewith. Such a frame, together with the heat exchange elements mounted therein, constitutes a heat-exchanger unit. A plurality of such heat-exchanger units can be arranged next to one another and/or above another in substantially vertical positions, to form an energy fence or a protective wall with heat-exchange capability. Then, the connecting pipes of the individual heat-exchanger units are connected to one another to establish a continuous flow pattern of the heat-transfer fluid through the arrangement.

Abstract: In a serpentine type evaporator comprising a serpentine tube provided therein with a plurality of coolant conduits and corrugated in a zigzag pattern, fins interposed between opposed outer surfaces of said serpentine tube, an inlet side header pipe connected to one end of said serpentine tube so as to communicate with said coolant conduits, and an outlet side header pipe connected to the other end of said serpentine tube so as to communicate with said coolant conduits, the improvement in a projection disposed within the outlet side header pipe.

Abstract: Time dependent fluctuations in a low pressure drop heat exchanger can be prevented by incorporating an improvement into the heat exchanger and practicing a method relating to the pressure drop across the heat exchanger tubes. The improvement comprises an orifice at or near the inlet of the tube wherein the flow flowing into the tube at a liquid inflow rate enters the tube in the liquid state and is then converted while in the tube into a gaseous state at some point downstream from the orifice. The tube is characterized at a given pressure. The fluid, now in a gaseous state, exits the tube at a gas outflow rate. The orifice is disposed at the input of the tube and is sized to provide an inlet pressure drop across the orifice to the liquid which enters the tube at a magnitude equal to a fractional portion of the low pressure drop across the tube itself.

Abstract: Disclosed is a heat exchanger comprising a plurality of parallel tubes and a plurality of ribs transverse to the tubes, and at least one connecting tank into which the tubes open. To obtain with simple and cost effectively produced means a uniform distribution of the fluid flowing through the heat exchanger over the heat exchanger tubes, the connecting tank has a chamber with a circular cross section and in the connecting tank a distributor installation is arranged which comprises a helical profiled body having an approximately stellate cross section which sealingly abuts with its ribs against the wall of the chamber. The partitions form a plurality of helical channels with one open and one closed end. An orifice is provided in the area of each channel for the passage of the fluid from the connecting tank into the tubes of the heat exchanger.

Abstract: Disclosed is an evaporator comprising a connector member, a Venturi distributor connected to the connector member for receiving and distributing a coolant, wherein the Venturi distributor divides the coolant into a plurality of streams, a plurality of channels formed in a body which comprises an insert for the connector member for conducting the coolant streams from the Venturi distributor, the channels corresponding in number to the streams with each channel being positioned to receive one of the streams from the Venturi distributor, a plurality of evaporator pipes connected to the connector member in parallel flow arrangement, the pipes corresponding in number to the channels with each pipe being connected to one of the channels, thereby forming a continuous coolant flow path from the Venturi distributor via the channels to the evaporator pipes, and a collection chamber formed in the connector member for receiving the coolant from the pipes.

Abstract: A tube and tube sheet assembly for a heat exchange device includes a plurality of heat exchanger tubes extending through a first and second tube sheet to provide a fluid-type passageway therebetween to enable a cooling fluid to be passed between the first and second tube sheets to reduce flashing of fluid introduced to the tubes. The fluid may be introduced into the tubes through the first tube sheet without turbulence or flashing because a smooth, continuous transition is provided therebetween by explosively forming the tubes within the tube sheet and providing openings communicating with each of the holes which are defined by the surface of revolution of an arc extending outwardly from the circumference of each hole to prevent formation of a Vena Contracta.

Abstract: The heat exchanger is constructed with a single pressure vessel to contain the ducts for the hot gas flow and the heating surfaces for the secondary medium. The heat exchanger is provided with a central duct for the hot process gas and two parallel branch ducts through which sub-flows of the process gas pass. A throttle member is provided in at least one of the branch ducts in order to throttle the flow of hot gas therethrough. Additional hot gas can be bypassed from the duct section into the exhaust gas from the pressure vessel.

Abstract: A heat exchanger with at least one main tube, closed off at one end, into which compressed air, which is to be heated, is admitted and, after being heated, is removed. The main tube has at least two channel guideways which are separated from one another in the longitudinal direction. U-shaped or curved compressed air lines project from the main tube and contact the hot gases. Each compressed air line is connected at one end to the channel guideway of the main tube into which compressed air is admitted, and at its other end with the channel guideway through which the heated compressed air is removed. The compressed air lines are formed primarily from hollow bodies, which extend in the direction of flow of the hot gas and which preferably are tapered at the inflow and outflow ends in order to aid the flow.

Abstract: The specification discloses a solar energy collector having a manifold with a manifold supply tube and a manifold return tube disposed therein. Fluid is supplied to the apparatus through the manifold supply tube and is received from the apparatus through the manifold return tube. A plurality of spaced apart riser U-tubes extend away and upwardly from the manifold with one end of the U-tube being in fluid communication with the manifold supply tube and the other end of the U-tube being in fluid communication with the manifold return tube. Dimples are formed in spaced apart positions along the supply tube and an orifice is formed in the center of the dimple. The U-tube is connected to the supply tube at the dimple, covering the orifice so that the orifice meters the fluid flow to the U-tube. A solar energy absorber tube encompasses each of the U-tubes.

Abstract: A distribution cap for a multitubular falling heat exchanger, in which the exchanger has a bundle of parallel tubes, an entrance channel for the tubes and a perpendicularly disposed distribution plate surrounding the entrance end of the tubes, the distribution cap is located in the entrance channel above the distribution plate and over the entrance ends of the tubes, and has cylindrical sidewalls and a closed top having sides that slope downwardly toward the cylindrical sidewalls of the cap.

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: An air cooled heat exchanger having an inlet flow distribution arrangement positioned within the inlet header to minimize maldistribution of entering fluid having a liquid-vapor mixture. The flow distribution arrangement includes a plurality of baffle means for directing the mixture entering the inlet header into defined flow channels in communication with groups of heat exchange tubes.

Abstract: In thermal cracking of hydrocarbons, especially steam cracking to light olefins, a transfer line heat exchanger unit is provided in which cracked gas flows from a furnace into heat exchange tubes, which comprises a distributor having an inlet for said gas and two or three diverging branches forming with said distributor a wye or tri-piece for passage of gas, each branch having along its length a substantially uniform cross-sectional area and being in fluid flow communication with a respective cooling tube. Unfired residence time and pressure drop are reduced, thereby improving selectivity to ethylene.

Abstract: A plate type heat exchanger in which liquid is injected into a vaporous fluid stream through orifices in a hollow slotted bar. The hollow bar is disposed transversely to the longitudinal axis of the heat exchanger, between and abutting facing surfaces of two metallic sheets. Vaporous fluid is admitted and distributed across the width of the heat exchanger in a first passage defined by the two metallic sheets, and flows through channels formed in the hollow bar where it abuts the sheets. The vaporous and liquid fluids mix, and after passing in heat transfer relationship with another fluid flowing in a second passage defined by adjacent metallic sheets, exit the heat exchanger. Since the hollow bar extends between the metallic sheets, it provides an effective structural support, permitting the heat exchanger to be used at relatively high operating pressures.

Abstract: In a radiator having flat tubes arranged in parallel and connected to header pipes for feed and return flow, each flat tube has two connection bores near the front end thereof. To enable the radiator to be manufactured by the use of pressure welding, a support part, angled into U-form with two bent ends arranged coaxially with the two connection bores, is inserted into each flat tube. These ends of the support part prevent the flat tube from being pressed inwardly during pressure welding. The portion of the support part extending parallel with the end edge of the flat tube is welded to the tube end edge, so that the support part simultaneously also forms the end closure wall of the flat tube.

Abstract: Device for reducing thermal stresses on a heat exchanger between two counterflow-circulating liquid alkali metal circuits comprising an annular cylindrical nest of tubes surrounding an axial pipe for the introduction of the liquid alkali metal to be heated and extended by an annular pipe for discharging the heated liquid alkali metal, wherein it comprises in the said annular pipe for discharging the heated liquid alkali metal means for radially homogenizing the temperature of the alkali metal, said means comprising pipes which, at the outlet of the nest of tubes, tap a part of the relatively hotter alkali metal flowing along the outer periphery of the annular pipe to bring it into its flow area closest to the axis.

Abstract: A heat exchanger, such as the radiator of a motor vehicle, has a nest of tubes through which liquid flows. To improve heat exchange between the liquid and the tube walls, turbulators (18) are inserted into the tubes to make the liquid flow turbulently. One form of turbulator is U-shaped and has two legs, each of which is inserted into a respective one of the tubes in the nest, via downstream ends (12) thereof. To avoid the liquid flow removing the turbulators from the tubes, stops or projections (19) are provided on either side of the bend in the turbulators. The projections may be moulded integrally with the water box which caps the downstream end of the nest of heat exchange tubes.

Abstract: A fireplace or stove apparatus for efficiently providing heat to a structure without loss of interior air to the flue draft. A blower forces outside air through a conduit located in the exhaust flue into a grate located in a fireplace or stove. The fuel loading opening of the fireplace or stove is made substantially air-tightly sealed. An air opening in the grate provides air to be consumed by the fire. A second air opening in the grate is fluidly connected by means of a conduit to the structure to be heated.

Abstract: A coupling used between headers of adjacent collectors in an array of solar collectors of the liquid heat-exchange type to balance the flow of heat exchange fluid through the absorber of each collector. The coupling is formed with an internal baffle in which an orifice of predetermined area is defined dependent on its position in the array.The coupling may also be used to vent entrapped air from the headers and to drain liquid from them.

Abstract: An improvement to the plate-type heat exchangers/vaporators constituted in per se known manner by a stack of a plurality of rectangular plates each having four orifices in the vicinity of the apices of the rectangle and thus constituting juxtaposed parallelelpipedic racks, alternately traversed in countercurrent by the hot fluid and the cold fluid, said cold racks having at their apex located in the vicinity of the cold fluid intake a strip having flow holes defining a cold fluid supply chamber and an evaporation chamber where the cold fluid evaporates by flowing as thin trickles in contact with the hot wall, the four orifices of each plate serving respectively for the admission and discharge of the cold and hot fluids, wherein the cold fluid intake is provided with a fitting or lining of a thermally insulating material which serves to create, by reducing the intake diameter, a supplementary pressure drop for said cold fluid and brings about a greater thermal gradient between said cold fluid and the hot plate

Abstract: The flow of cracked gases, for example, from an ethylene plant through the tubes of a transfer line heat exchanger is equalized by employing larger cross-section tubes in the outer portion of the exchanger and smaller cross-section tubes in the inner portion of the exchanger thereby preventing, or substantially minimizing, build-up of coke deposits in the exchanger, especially in the inlets of the tubes in the outer portion where coke formation conventionally occurs.

Abstract: A heat exchanger module, such as a solar collector module, comprising a tube sheet (3) connected to a header (4). The tube sheet (3) passes through an opening in the header (4) so that the end of the sheet (5) protrudes a distance into the header (4), the header opening being united to the surface of the tube sheet (3) so that the tendency of the tube sheet (3) to burst or split open in the region of the junction of the tube sheet and header is minimized when the module is under fluid pressure. By the term "tube sheet" is meant a substantially planar sheet having an upper and a lower plastic membrane interconnected by a series of spaced division walls thereby forming a series of tubes arranged generally in a flat plane across the sheet, the tubes being continuous through the sheet and open at the two opposite ends of the sheet. The term also includes a sheet of circular tubes joined in side-by-side relationship.

Abstract: An improved method of making a solar energy collector is disclosed. The method involves fusing a collector panel to headers using a high frequency magnetic field. End fitments are also fused to the headers. Other improvements in solar energy collectors per se are also disclosed.

Abstract: The invention relates to a heat transfer from waste water from a building back to the building. The waste water is supplied to a waste pipe (2) in such a way that it is forced to flow downwardly in the pipe along its inner wall. Heat from the waste water is transmitted to a medium flowing on the outside of the pipe.

Abstract: A solar collector of modular configuration includes a plurality of evacuated collector elements disposed on opposite faces of a manifold in a staggered array. The manifold includes a central baffle which divides it into two parallel passageways through which the heat transfer medium, typically art, may be supplied to and removed from the collector elements. Each of the collector elements comprises an elongate double wall glass tube with one open end, the annulus between the walls being evacuated to a high vacuum. A thin wall metal distributor tube having a diameter marginally smaller than the inside diameter of the collector element and a length marginally longer seats within the collector element. The annulus defined by the distributor tube and inner collector element wall communicates with the proximate passageway and the distributor tube communicates with the distant passageway.

Abstract: In a reactor housing for conducting the catalytic oxidation of gaseous sulfur compounds, a plurality of empty tubes are arranged in an outer zone of the housing for having incoming gas to be reacted flow therethrough. Larger catalyst-filled tubes are arranged in an intermediate zone for having the gas flow therethrough after flowing through the empty tubes for performing the catalytic oxidation in the larger catalyst-filled tubes. An inner chamber includes an axial-flow pump arranged therein and is in communication with the outer and intermediate zones in such a way that a heat-transfer agent is caused to flow cross-currently into and out of the outer zone, intermediate zone and inner chamber for contacting the empty tubes and catalyst-filled tubes.

Abstract: In order to reduce the difference in stress of the tubes through which heating steam is flowing in the case of heat exchangers where the tubes are concentrated in at least two horizontal bundles and where heating steam flows through the tubes and a power medium flows around the tubes, it is proposed that there are arranged at the intake openings of the tubes (1) through which the heating steam is flowing baffles (3) with different intake profiles (4) in such manner that within each bundle of tubes the intake profiles (4) will become smaller in direction of flow of the power medium to be heated.

Abstract: The invention concerns a heat exchanger which is intended for exchanging heat between a first medium passing through a tube system and a second medium which flows around the tube system whereby the tube system comprises a plurality of tubes which are connected in parallel between an inlet and an outlet for the first medium. The tube system is enclosed in a casing which is composed of two halves, which casing is so designed that a channel is formed for the second medium from an inlet to an outlet for this second medium, said channel being formed by mutually substantially parallel parts connected with each other by means of substantially semi-circular parts. The channel comprises the tubes which form the tube system, said tubes having corresponding straight parts and semi-circular parts. The tubes, which may be provided with cross grooves, can be arranged in a direction which is perpendicular to the mean plane of the casing and can be flattened in this direction.

Abstract: A series of tubes wound in spiral, spaced relation in pressure contact with the next inner tube or a central cylinder to form, between them, a spiral path for one liquid flowing upwardly in the space between the tubes, while another liquid flows downwardly in the tubes. The outermost tube may be enclosed by a sheath in pressure contact therewith, while several sets of tubes, separated by corresponding sheaths, may be utilized. The diameter of the tubes may be varied for the sets to compensate for the greater length of tubes at an outer position, so that an approximately equal time of travel from one end of the tubes to the opposite ends may be obtained. The spacing between the successive turns of the coils is preferably a distance corresponding to one half the diameter of the tubes.

Abstract: A body of water having a liquid level and an outer edge is provided with a water heater having a collector formed as an array of adjacent and substantially concentric annular flexible tubes that surround the body at the edge and that has a rectified equal to at least 30 times its horizontal cross-sectional width. The tubes have exposed upper surfaces and feed ends connected to a feed manifold and return ends connected to a return manifold. Respective feed and return conduits are connected to the feed and return manifolds and both open into the body of water below the liquid level thereof. A pump is provided in one of the conduits for drawing water from the body into the feed conduit, then passing it sequentially through the feed conduit, the feed manifold, the tubes, the return manifold, and the return conduit, and for expelling the water into the body from the return conduit.