Abstract: A heat exchanging arrangement for a subsea electronic system, the heat exchanging arrangement including: at least one pipe having an external surface; and at least one heat exchanging element arranged inside the at least one pipe and defining at least one internal passage for conducting a dielectric fluid through the at least one pipe; wherein the at least one heat exchanging element is arranged to press laterally outwards against an internal surface of the at least one pipe to establish a heat transfer bond between the at least one heat exchanging element and the at least one pipe. A subsea electronic system including the heat exchanging arrangement is also provided.

Abstract: An exhaust structure includes an intake section which includes an inlet, an output section which includes an outlet, and a piping section coupled to the intake section and the output section at a section interface. The piping section includes a first inner diameter from the intake section to the output section, wherein one of the intake section or the output section has a second inner diameter at the section interface. The second inner diameter includes a same value as a value of the first inner diameter. A plurality of smoothing layers are configured to resist turbulence and condensation produced by a flow of one or more gasses in the intake section, the output section, and the piping section.

Abstract: A pavement striping devices for heating and applying thermoplastic material to a road surface is provided. The pavement striping device includes of: a hopper for holding a supply of particulate thermoplastic marking material in a non-molten state, an air or oil-heat transfer medium melting kettle having a series of coaxial conveyored or unconveyored conduits within, a plastic extruder for transporting the thermoplastic particulate from the hopper to the series of coaxial conveyored or unconveyored conduits with the air or oil-heat transfer medium melting kettle, a heating mechanism for heating the air or oil-heat transfer medium melting kettle and the plastic extruder to a temperature suitable for melting thermoplastic, and a means for driving the stream of molten thermoplastic through the series of coaxial conveyored or unconveyored conduits to a sprayer or extrusion die, all of which form a means by which the molten thermoplastic is directed to the pavement surface.

Abstract: In an inner fin, a plate is made up of a top part, a bottom part, and a wall plate part, and a channel having a concave-shaped cross section and a channel having an inverted concave-shaped cross section are alternately repeated as channels of the gas by a pair of the wall plate parts facing each other. The wall plate part for each of the channels has a shape in which the wall plate part is bent left and right in a serpentine shape and projected and recessed parts thereof are alternately repeated and formed, and the recessed part of the wall plate part is formed with a chevron-shaped part made up of an upward slope part that ranges from a base part to the top part and a downward slope part that passes downward from the top part to a neighboring base part.

Abstract: An exhaust structure includes an intake section including a first high thermal conductivity material, the intake section having an inlet, an output section including a second high thermal conductivity material, the output section having an outlet, and a piping section including a third high thermal conductivity material, the piping section being configured to communicatively couple the intake section with the output section. The exhaust structure provides a high thermal conductivity path from the inlet to the outlet, the high thermal conductivity path including the first high thermal conductivity material, the second high thermal conductivity material, and the third high thermal conductivity material.

Abstract: A portable induction heater with a rotating head portion which can be used to rapidly, detachably connect a work coil. The portable induction heater is also provided with various other advantages detailed here.

Abstract: The invention provides a modular device for latent heat storage, which is made of a conduit with a first end and a second end; and a jacket that surrounds a portion of the conduit between the first end and the second end, wherein the jacket is comprised of at least one phase change material. The invention further provides a system for latent heat storage, comprising a thermally insulated enclosure adapted to receive at least one modular latent heat storage device and a HTF, wherein the HTF flows from an upstream heat source into each of the first ends of the conduit and out of each of the second ends of the conduit comprising the at least one module to a downstream heat exchanger.

Abstract: A forced convection fin tube condensing heat exchanger for supplying heat includes a shell, burner and fin tubes bundle. The burner is at the top of the shell, circular fin tubes bundle installed around the burner tightly, circularly and coaxially. The flue channel which is formed by the shell and a row of fin tubes bundle is below the burner. The flue flows along the flue channel to flue outlet. There are front and rear water manifolds at the two ends of the fin tubes. Water baffles inside the rear water manifold divide the rear water manifold into water inlet and outlet areas. The water enters the small portion of circular fin tubes bundle from water inlet area, through the front water manifold, back to the water outlet area via the main portion of the circular fin tubes bundle. The use of bent fin tube to improves efficiency.

Abstract: A connector system with improved thermal management is provided. A module includes a thermal dissipation system. A receptacle is provided that has a cage with thermal channels that allow air passing through the receptacle to directly remove thermal energy from the thermal dissipation system and carry the thermal energy out of the cage.

Abstract: A fluid reservoir comprises a first compartment, a second compartment, a port, a drain, and a tube. The port is fluidly connected to the first compartment and positioned at a port height. The drain is fluidly connected to the first compartment and the second compartment. An entrance to the drain is positioned in the first compartment at a drain entrance height which is lower than the port height. The tube is fluidly connected to the first compartment and the second compartment. An entrance to the tube is positioned in the first compartment at a tube entrance height which is higher than the drain height.

Abstract: An apparatus includes an inlet, an outlet, and a sheet disposed proximate a heat transfer surface, wherein the sheet is oriented in a sheet plane that is displaced from a plane of the heat transfer surface by an angle of at least 10 degrees. The apparatus also includes a plurality of tabs attached to the sheet, the tabs lying in respective tab planes, wherein the tab planes and the sheet plane intersect forming respective intersections. The intersections of the tab planes and the sheet plane are substantially parallel. The intersections of the tab planes and the sheet plane are at an angle of less than 88° to the heat transfer surface, and the plurality of tabs collectively form channels directing a fluid passing from the inlet to the outlet to impinge the heat transfer surface.

Abstract: Provided is a cold-storage heat exchanger. The cold-storage heat exchanger includes a pair of header tanks, and tubes which are arranged in three rows with respect to the direction of the flow of air and connected at opposite sides thereof to the header tanks. A cold-storage medium is stored in the tubes that are disposed in a middle row, and refrigerant circulates through the tubes that are disposed in front and rear rows. Therefore, the cold-storage medium can effectively store cold-energy transferred from the refrigerant. When the engine of a vehicle is stopping, the cold-storage heat exchanger can discharge the cold-energy that has been stored into the passenger compartment of the vehicle, thus preventing the temperature in the passenger compartment from rapidly increasing, thereby creating pleasant air-conditioned conditions for a user, and minimizing the energy and time required to re-cool the passenger compartment.

Abstract: An apparatus includes an inlet, an outlet, and a sheet disposed proximate a heat transfer surface, wherein the sheet is oriented in a sheet plane that is displaced from a plane of the heat transfer surface by an angle of at least 10 degrees. The apparatus also includes a plurality of tabs attached to the sheet, the tabs lying in respective tab planes, wherein the tab planes and the sheet plane intersect forming respective intersections. The intersections of the tab planes and the sheet plane are substantially parallel. The intersections of the tab planes and the sheet plane are at an angle of less than 88° to the heat transfer surface, and the plurality of tabs collectively form channels directing a fluid passing from the inlet to the outlet to impinge the heat transfer surface.

Abstract: The present invention relates to an apparatus and method for an air bypass system for a natural draft cooling tower that employs a wet heat exchanger, a direct dry heat exchanger or an indirect dry heat exchanger to extract heat from a heated fluid, which is usually liquid or steam.

Abstract: A heat exchanger is provided that may include a shell; a first pipe that guides a first fluid into the shell; a tube, through which a second fluid that exchanges heat with the first fluid may pass; a second pipe, through which the first fluid is guided outside of the shell; and a base including a fastening portion to which the shell may be fastened and a support portion that supports the fastening portion. The fastening portion may have a tube hole, through which the tube may pass, and a pipe hole, through which at least one of the first pipe or the second pipe may pass, so that it is possible to increase availability of space at a side of and above the shell, and at least one of the first pipe, the second pipe, or the tube may be protected by the base, resulting in high reliability.

Abstract: A device for reducing temperature variation in a plenum includes at least one pipe and a plurality of sumps containing a fluid operable to vary between a liquid state and a gaseous state depending upon a temperature of the fluid. The plurality of sumps are positioned at various locations within the plenum and the at least one pipe is in fluid communication with the plurality of sumps. In addition, the fluid, in the gaseous state, is caused to move through the at least one pipe and condense, thereby reducing the temperature at the location of the sump where the fluid was vaporized and thereby reducing temperature variation in the plenum.

Abstract: A device, system and method for heating fluid (air) in a flue to create a draw prior to combusting a fuel in a combustion device. The device, system and method includes a housing that may be integrated about the flue. The housing may include a heat exchanger that itself may include a heating source that may be in thermal communication with the flue and a temperature differentiation driver. The heat exchanger may operate to transfer heat energy from the heating source to a fluid constrained to a path created by the flue. The result is a pressure differential created within the flue to help draw the fluid out of the combustion device. The heat exchanger may be configured such that it may cause heat transfer to the heavier, more dense fluid contained within the ventilation system prior to combusting fuel in a combustion device, thereby causing the fluid to be relatively less dense thus creating a draw.

Abstract: The present invention relates to a natural draft cooling tower that employs an air cooled condenser. The aforementioned cooling tower operates by natural draft and achieves the exchange of heat between two fluids such as atmospheric air, ordinarily, and another fluid which is usually steam. The aforementioned cooling tower utilizes a central steam duct riser supplying steam to perimeter ducting via radial ducting.

Abstract: A wind turbine with a thermal siphoning system is disclosed. The wind turbine comprises a tower of a wind turbine, the tower having a top and a base, and a thermal siphoning system for cooling heat generating components. The thermal siphoning system is located within the wind turbine tower and comprises a liquid coolant and at least one heat generating component located near the base of the tower. The heat generating component is adapted to receive the coolant through a coolant inlet port and adapted to discharge the coolant through a coolant outlet port. The thermal siphoning system further comprises a hot coolant tube connected to the coolant outlet port of the heat generating component.

Abstract: A solar water heating and cooling system including a solar energy collection assembly having a heat absorbing element, a heat exchanger and a shield. The system also includes a cooling assembly, the cooling assembly is integral with the shield. The system has a check valve in fluid communication with the solar collection assembly and the cooling assembly, and a fluid pump in fluid communication with the solar energy collection assembly. A working fluid is disposed within the solar energy collection assembly, the cooling assembly, the check valve and the fluid pump. A cooling loop is defined by the solar energy collection assembly, the cooling assembly and the check valve. When the fluid pump is off, the working fluid circulates through the cooling loop, but when the fluid pump is on, the working fluid circulates through a heating loop that is defined by the solar energy collection assembly and the fluid pump.

Abstract: A ring heat dissipating device is mainly assembled by a ring body, a bottom plate arranged inside the ring body, and a plurality of heat dissipating fins arranged outside the ring body. The bottom plate is punched by a mold so that the bottom plate is fixed to a predetermined position inside the ring body. The heat dissipating fins are inserted into slots on an outer surface of the ring body. After trenches between the slots are punched and deformed, the heat dissipating fins are tightly riveted by the deformed trenches.

Abstract: A directional thermal siphon type heat column comprises: a column body which is a sealed hollow cavity formed by a lid and a base and contains a liquid; and at least one partition element, being a hood plate fixed into the column body and extended obliquely towards the base and having a first channel formed on a side of the partition element opposite to the base and a second channel formed on one side of the partition element opposite to the lid, so as to avoid an opposite flushing occurred while the liquid inside the heat column is having a liquid/vapor phase change and prevent affecting the heat dissipation and circulation operation efficiency.

Abstract: A system in a radio network node for regulating temperature of electronic equipment comprises the electronic equipment and a heat exchanger unit (200), comprising an evaporator unit (202), a condenser unit (203), and a first pipe (204). The first pipe (204) is arranged to connect the evaporator unit (202) and the condenser unit (203). A second fluid is flowable from the condenser unit (203) to the evaporator unit (202) in the first pipe (204). Furthermore, the system comprises a heater unit (201) arranged at the first pipe (204) and arranged to heat the second fluid in the first pipe (204) such that flow in the first pipe (204) is restricted. Furthermore, an arrangement (160) for restricting flow in a heat exchanger unit is provided.

Abstract: An apparatus is provided for drying a gas by gradually releasing and condensing the moisture in various chambers of a column, different pressures and different temperatures thus being present in the chambers of the column. The gas to be dried is first fed into the bottom chamber, where the largest amount of the water contained in the gas is condensed, and the gas is then discharged from the bottom chamber via a nozzle. Subsequently the gas is cooled and fed into at least one more chamber located above the first chamber, where further moisture is condensed before the resulting condensate is fed via a pipe—preferably shaped like a siphon—into the bottom reservoir to prevent the gas from flowing from the chamber below into the chamber above. A process which enables a gas to be dried is also described.

Abstract: A capillary assisted loop thermosiphon apparatus (100) has at least one evaporator (102) connected by a vapor line (104) to a condenser (106); a liquid line (108) connects the condenser (106) and the evaporator (102), the evaporator (102) is in the direction of gravity from the condenser (106) for the condenser (106) to supply liquid under gravity induced pressure to the evaporator (102), and the evaporator (102) has a vertical capillary wick (102a) in which liquid wicks in the direction of gravity.

Abstract: A method for manufacturing a plate-type heat exchanger in which a heat medium is sealed in a hollow part of an airtight structure formed in the interior of a plate-like container, and the heat medium is moved by capillary force from a condensing part to an evaporating part in the hollow part along heat-medium-guiding grooves formed in the container's inside surface portions that face the hollow part; wherein a plastic workable metal plate of specific thermal conductivity is prepared; a carving tool is used to repeatedly carve out a surface portion of the metal plate at specific intervals along the surface portion, forming a plurality of plate-like fins; and a plurality of grooves formed between these fins is used as heat-medium-guiding grooves.

Abstract: Thermal transfer coating comprising a plurality of metal bodies and a plurality of interstitial elements disposed between and connecting the plurality of metal bodies to one another. The metal bodies comprise an inner portion comprising a first metal and an outer portion comprising an alloy comprising the first metal and a second metal. The interstitial elements comprise the alloy of the outer portion.

Abstract: A device, system and method for heating fluid (air) in a flue to create a draw prior to combusting a fuel in a combustion device. The device, system and method includes a housing that may be integrated about the flue. The housing may include a heat exchanger that itself may include a heating source that may be in thermal communication with the flue and a temperature differentiation driver. The heat exchanger may operate to transfer heat energy from the heating source to a fluid constrained to a path created by the flue. The result is a pressure differential created within the flue to help draw the fluid out of the combustion device. The heat exchanger may be configured such that it may cause heat transfer to the heavier, more dense fluid contained within the ventilation system prior to combusting fuel in a combustion device, thereby causing the fluid to be relatively less dense thus creating a draw.

Abstract: A system (10) and method for removing heat from an engine compartment in a motor vehicle where heat generated by operation of a heat engine (12) that propels the vehicle tends to collect. Engine heat is collected in a thermofluid in a reservoir forming an evaporator (14) where the thermofluid absorbs heat sufficient to evaporate it. The vapor naturally migrates to a condenser (22) that is cooled sufficiently to condense the vapor back to liquid phase. The liquid falls by gravity back to the condenser.

Abstract: Methods and apparatuses are provided for the removal and transportation of thermal energy from a heat source to a distant complex for use in thermochemical cycles or other processes. In one embodiment, an apparatus includes a hybrid heat pipes/thermosyphon intermediate heat exchanger (HPTIHX) system that is divided into three distinct sections, namely: an evaporation chamber, a condensation chamber, and a working fluid transport section of liquid and vapor counter-current flows.

Abstract: A heated flooring module is provided for livestock stables, which includes an upper plaque, for walking on, which is essentially level; a hollowed central section, with no bottom surface, whose upper surface is equipped with at least one continuous runnel, adapted to contain a heat source that enters and exits the runnel through respective entry and exit tubular segments, with the abovementioned hollowed central section equipped with suspension elements for being suspended from resistant elements such as the bars of a horizontal grid; and an optional under-lid, all of the above arranged in such a way that, when the upper plaque is welded to the upper surface of the hollowed central section, the continuous runnel forms an enclosed circuit which contains the heat source inside, leaving the under-lid fitted into the underside of the hollowed central section.

Abstract: An electronic device has at least one component that is capable of generating a quantity of heat. The electronic device further has an air-moving device and an air duct. The air moving device is capable of creating a flow of air that removes a portion of the quantity of heat. The flow of air enters the air duct. The air duct has a restriction chamber that includes a venturi vent in which the flow of air into the duct and through the restriction chamber creates a new flow of air into the venturi vent. The new flow of air into the venturi vent does not pass over the at least one component in the electronic device.

Abstract: A heat sink for free convection cooling in horizontal applications is provided. Specifically, the heat sink includes a plurality of spaced apart cooling fins, which are supported by an angled base. The cooling fins are transversely attached to the base and extend in a substantially vertical direction. In addition, the cooling fins extend beyond an outer edge of the base so that air can flow horizontally beneath the base and then vertically through the spaced apart cooling fins.

Abstract: The present invention is directed to a thermosyphon heat exchanger. The thermosyphon system eliminates the need for costly and inefficient moving parts in the cooling system. The system also minimizes failures rendering the system inoperable by eliminating mechanical components subject to breakdowns that would render the system inoperable. The design of the heat exchanger coils provides for increased efficiency, reduced cost, and simplified construction and maintenance. The system further reduces the energy consumption required for cooling operation while still providing excellent cooling performance.

Abstract: [Object] To provide a duct with high sound absorbing effect and sufficient exhausting efficiency and an electronic apparatus having the duct

Abstract: A system and method are provided for cooling transformers utilizing a fluid to air heat exchanger to cool dielectric fluid flowing through the transformer. The system includes multiple vertical cooling tubes in fluid communication with the transformer to cool the dielectric fluid. The tubes are configured to create vertical air passages such that the system utilizes natural convection air flow and thermal siphoning to cool the fluid.

Abstract: Chimney-like cooling passages that have opposite outlet and inlet end regions open to ambient air also have central regions that extend through heated components of industrial furnaces. The passages preferably are defined by conduits that are oriented and configured in a manner that enables thermally induced flows of ambient air to self establish through the conduits to cool the furnace components once the furnace components become heated. The passages function like chimneys, with each having its outlet located higher than its inlet so that ambient air will effectively rise as it flows from the inlet to the outlet. The passages may provide increases in cross-sectional area somewhere along their lengths so that heated ambient air expanding in the passages is encouraged to discharge from the less restrictive, larger area outlets rather than from the smaller area inlets.

Abstract: An electric heater includes a receiving chamber, heat sink members, electric heating pipes and a control portion. The receiving chamber and heat sink members are formed from extruded aluminum members. The heat sink members are sequentially arranged at both sides of the receiving chamber. The electric heating pipes are placed in the receiving chamber. The control unit activates an electric power source of the electric heating pipes in order to generate heat. Heat energy from the electric heating pipes is absorbed by extruded aluminum plates that define the receiving chamber. Heat energy is conducted quickly to the heat sink members which exchanges heat by convection with ambient cool air to rapidly raise the temperature of a room.

Abstract: A heat exchanger system suitable for facilitating the economical cooling of hot fluids in the vicinity of a body of water. The preferred embodiment of the present invention contemplates a vertical, or combination vertical and horizontal thermosyphonic, passive, heat exchanger column situated in a body of water and enveloped by a caisson or the like, and configured to facilitate, through percolation, enhanced circulation of seawater therethrough and effecting significant cooling of a hot, hydrocarbon well stream, or other hot fluid in the vicinity of a body of water. A vertically situated bundle of tubes forms the heat exchanger, which may include a system of staggered baffles to direct the flow of cooling seawater to effect even temperature distribution throughout the tube bundle. The present system further teaches a system for cooling high pressure, hot fluids as may be found in a deep hydrocarbon reserve offshore, utilizing a the vertical heat exchange column of the present invention.

Abstract: A device including a side wall (3) and bottom walls (4, 5) together forming a metal vessel (2) containing a core (7) for exchanging heat between two fluids, i.e. preferably counter-flowing heating and heated fluids. The core is arranged vertically within the chamber and radiates heat towards the inner surface of the side wall through an intermediate space (24) provided between said wall and the core and filled with a fluid which is the same as or different from one of the fluids flowing therethrough. The chamber is cooled both by exposing the side wall (3) to the atmosphere and by using a thermosiphon effect to cause the fluid in the intermediate space (24) to flow through a closed circuit (30) including said intermediate space and at least one pipe (31) located outside the chamber and connected thereto at two vertically spaced points. The device may be used in oil industry exchangers.

Abstract: A structure or cooling a large cylindrical storage tank has the shape of an inverted funnel and is intended to be disposed over the tank receiving the upper portion therein and internal struts are provided to separate the funnel wall from the tank wall, The separation allows the entry of air into the funnel structure so that as the structure is heated by the sun air currents will rise through the funnel exiting the chimney which will result in an inflow of air into the funnel around the walls of the tank.

Abstract: A tube supporting device is provided for supporting closely packed tubes in a heat exchanger. The device has a support plate transversely disposed with respect to the tubes. The support plate has a plurality of holes formed therein which are penetrated by the tubes and which support the tubes against lateral movement. The holes can be a variety of shapes to create one or more gaps between the peripheral surfaces of the holes and the outer surfaces of the tubes. The gaps enhance the flow of condensate which has formed on the tubes and causes the condensate to flow to a bottom portion of the heat exchanger without moving to and collecting on the support plate. The holes also inhibit lateral movement of the tubes.

Abstract: An improved air flow enhancing stack for use with an air cooled heat exchanger designed for natural convection cooling. The stack includes a lower conical section having a larger end attached to the natural convection air exhaust from the heat exchanger and a smaller end positioned above the larger end. A central cylindrical section having a diameter equal to the diameter of the smaller end of the lower conical section is attached to the upper end of the lower conical section. An upper conical section, having a smaller end of diameter equal to the cylindrical section, is attached to the upper end of the cylindrical section and has its larger end positioned above its smaller end. A complete air enhancing stack provides improved convection cooling as compared to a conventional straight exhaust stack.

Abstract: In a method for cooling rooms, the energy exchange between warm room air and cold air takes place through inherent convection of the air by means of a drop shaft arranged in the room, which has cooling surfaces in its upper part, at which the in-coming warm room air cools, and flows downwards owing to the specific weight difference. The cooled air leaves the drop shaft at the lower end in a laminar flow and then spreads in the room in an unbroken cool layer. The air leaving the drop shaft can also be deflected into a hollow floor. It is possible to use a fan to add to the cooled air current moved by gravity disturbing air, which then occasions turbulence.

Abstract: This invention pertains to improvements in the design of reservoirs for hydraulic systems, by providing self regulated temperature control for hydraulic fluids. The unique features of the reservoir of my invention include; an interconnected multi-chamber design with integrated vertical heat transfer tubes, for conductive and convective heat transfer from the hydraulic fluid to the surrounding atmosphere.

Abstract: A radiator comprising a plurality of longitudinally finned tubes formed from extruded aluminum and extending between upper and lower header pipes likewise of extruded aluminum. A water-tight joint is formed at the junction of each finned tube with the adjacent header by means of an interference fit nipple. The fins are shaped so as to define a gap between adjacent finned tubes through which air to be heated may be drawn. Such air enters a chamber defined between each adjacent pair of finned tubes and exits to the rear via louvers formed in the rear fins of the finned tubes, taking the general direction of arrows A. A degree of control of the heat output of the radiator may be achieved by rotation of a flap located at the bottom of the space between the radiator and the adjacent wall surface.

Abstract: In order to cool heat generating components on an electronic assembly without contamination by particles carried in a cooling gas stream, a cold plate is disposed adjacent the assembly, defining a gap region therebetween. The cooling gas is directed in proximity to the cold plate, dissipating heat transferred from the components to the plate. To enhance overall heat dissipation of the apparatus, an aperture is defined between the gap region and the gas stream, so that a negative pressure is induced in the gap by virtue of the Bernoulli principle. This pressure difference induces convection within the gap, increasing heat flow between the components and the plate, and resulting in overall improvement in heat dissipation. Embodiments in which the gas stream flow is parallel and transverse to the cold plate are described.

Abstract: A liquid cooling system for a super-charged internal combustion engine in which the turbocharger is connected to the forced circulatory cooling system effective during the operation of the engine. In order to prevent an overheating of the turbocharger after the internal combustion engine is turned off, the turbocharger is equipped with a further cooling circulatory system maintained by thermo-syphoning action. A volume expansion tank present in the cooling circulatory system of the internal combustion engine is thereby used as heat exchanger for cooling off the cooling liquid, which is constructively matched for this particular application.

Abstract: A convector heater has a front plate 1 with a surround 2 spaced around the periphery of the front plate 1 so as to define a top, bottom and side air gap 3 between the front plate 1 and the surround 2. A back plate 4 is connected at its periphery to the surround 2 and is spaced from the front plate 1 so as to define a convection air space 7 between the front plate 1 and the back plate 4. The convection air space 7 is open to the surrounding atmoshere at the air gap 3. A heat exchanger, such as an electric heater, is disposed at the bottom of the convection air space 7 for heating air to induce a convection air flow through the convection air space 7 from the bottom air gap 3b to the top air gap 3a. A secondary air flow is induced into the air space 7 through the side gaps 3c, 3d by the main convection air flow.

Abstract: One exchanger unit comprises a length of exhaust pipe tube having a plurality of smaller heat exchange tubes which extend diametrically through the exhaust pipe tube. Each of the heat exchange tubes is canted slightly longitudinally of the exhaust pipe tube and the heat exchange tubes are disposed in a helical configuration to force the exhaust gases to swirl through the exhaust pipe tube. The heat exchanger units can be disposed in a furnace exhaust pipe or can be arranged between inlet and outlet plenums which are connected in a furnace exhaust pipe or the like.