Abstract: A compact highly efficient heat exchanger is used to utilize waste heat from a motor vehicle engine cooling system to heat a source of water for use with a shower or the like in a recreational environment. The heat exchanger comprises a hollow cylinder having a cylindrical wall to define an annular space therebetween. Within the annular space is located a neatly fitting helical tubular coil with spaced helixes to define a helical pathway between adjacent coil helixes working fluid passes through the tubular coil and process fluid passes through the helical pathway to effect heat exchange between the working and process fluids.

Abstract: The present protective/cooling system includes a housing which contains electronic circuitry and optics for a vision system typically operating in a high temperature, turbulent dust and debris environment. The vision system is located in an inner chamber which is sealed from the surrounding harsh environment. A cooling fluid flows through spiral passages around the inner chamber for drawing heat from the contained vision system. The cooling fluid exits across an optical interface in a spiral flow pattern which enhances both the cleaning ability and the cooling efficiency of the cooling system.

Abstract: A heat exchanger is provided with a first conduit which utilizes a reverse spiral concept and a second fluid conduit which directs a fluid in thermal communication with the first conduit. One of the fluid conduits of the heat exchanger is formed with a generally S-shaped portion which creates a reverse spiral configuration and which permits a heat exchanger to take advantage of the spiral conduit design while avoiding the typical disadvantages that are generally experienced with spiral conduit configurations. The reverse spiral concept permits both ends of the reverse spiral tube to be easily accessible from a radially outward direction relative to the spiral configuration.

Abstract: A heat exchanger preferably for use in heating physiological fluids includes an inner conduit, an outer conduit, and end caps which seal the outer conduit to the inner conduit to form a flow channel. The inner conduit is preferably of aluminum and the outer conduit and end caps are of an elastomeric material. The end caps are designed to tightly engage the inner conduit and to be solvent bonded to the outer conduit. When the inner conduit elongates because of thermal expansion, the outer conduit elastically deforms so that there is no relative movement between the end cap and the inner conduit. This preserves sterility during temperature variation.

Abstract: A heat exchanger includes a porous cylindrical sleeve with a bore into which liquid coolant is admitted. The liquid permeates the sleeve but cannot leave the outer surface. A pipe surrounds the sleeve. The pipe has a cylindrical outer surface and an inner surface defining protrusions and vapor channels about the protrusions. The inner ends of the protrusions bear against the outer surface of the sleeve. A plurality of helical channels are helically arranged about and in thermal contact with the outer surface of the pipe. The ends of the helical channels are coupled to plenums. Each plenum is coupled by a pipe and a fluid disconnect to one end of a thermal loop including a heat source. Heat-laden vapor passes through the helical channels and is cooled to liquid. The heat is withdrawn into the pipe and passes through the protuberances to vaporize the liquid near the surface of the porous sleeve. The resulting vapor is collected and coupled to a condenser.

Abstract: Heat is more efficiently transferred to the catalyst tubes in a fuel cell power plant reformer by mounting sleeves about the individual catalyst tubes. The sleeves define helical hot gas flow paths on the outside of the catalyst tubes. Adjacent flow paths are separated from each other by arcuate ribs between the tubes and sleeves that provide line contact with the outer surface of the tubes for improved heat transfer. The ribs may be formed with circular rods attached to the tubes or sleeves, or by helical grooves with semi-circular configurations formed in the sleeves. Approximately fifty percent greater heat transfer can be achieved using the line contact ribs to form the hot gas flow paths. The sleeves, tubes and ribs are all made of metal.

Abstract: A resist developing apparatus comprising a developing tank consisting of a top portion, a body portion, and a bottom portion, at least one of the top, body, and bottom portions being comprised of an inner wall and an outer wall, a heat exchange chamber being defined between the inner and outer walls for being supplied with a heating medium; a chuck disposed inside the developing tank for holding a work piece in position, a nozzle for spraying chemical liquid toward the work piece held in position by the chuck; a heating medium supply unit for supplying heating medium at a specified temperature to the heat exchange chamber; and piping connecting between the heating medium supply unit and the heat exchange chamber, whereby the interior of the developing tank is adapted to be controlled to a specified temperature.

Abstract: A compact, reliable, and efficient cryogenic cooling system that can provide cryogenic cooling for a variety of desirable uses. The system is particularly desirable to provide cooling for infrared detectors in temperature ranges from 40K to 77K, and may be advantageously used in multi-stage systems to produce temperatures as low as 5K. In cryogenic cooling systems using a compressor and Joule-Thomson valves, working fluids, such as nitrogen, can be precooled to temperatures substantially below 165K at the input to a Joule-Thomson valve, and the power input to systems of our invention providing cooling 77K, for example, can be reduced by a factor of 4.5.

Abstract: An object of the invention is to cool a rich burn combustor without extracting excessive amounts of heat and to use the extracted heat. In accordance with the invention, a combustor (10) having a primary combustor (12) and a secondary combustor (13) with a throat (20) between them is provided with a jacket including a wall (27) radially outwardly of a wall (14) of the primary combustor (12). Steam is injected into a manifold (33) at the throat end of combustor (12) and flows in a plurality of spiral paths through the space between walls (14) and (27) to an outlet manifold (32) at the other end of combustor (12) becoming superheated. The superheated steam is employed to drive a stream utilization device. The spiral steam flow paths are established by barriers (38) wound in spiral fashion on the outside of wall (14) of the combustor (12). Another object is to minimize stress on the wall (14) of the primary combustor (12).

Abstract: A self-contained portable unit for heating physiological fluids is disclosed. A heat exchanger is disposable to ensure sterility, and the heat exchanger is attached to a heating system by inserting it between opposed fluid connection elements. One of the fluid connection elements is movable to permit the heat exchanger to be installed and removed easily by inserting one end of the heat exchanger in one of the fluid connection units and moving the other fluid connection unit into contact with an opposite end of the heat exchanger. The heating fluid is heated by an electric heating element and is circulated by an electric pump.

Abstract: A heat exchanger for exchange of heat between two media, especially gas and liquid, in heat pumps and the like, including an elongated, generally cylindrical space (2) passed through by one medium and having an inlet (3) arranged at one end and an outlet (7) at the other end, and a helical wall radially defining said space and delimiting a space through which the other medium is intended to flow.

Abstract: A compact unitary heat exchanger and debubbler for a liquid includes an elongated heat exchange element having an inverted V-shape and a vertically-extending debubbling chamber located between the legs of the inverted V. The heat exchange element is made up of an inner tube surrounded by an outer tube, so that a heat exchange fluid such as water flowing within the inner tube exchanges heat with a treated liquid flowing within a space defined between the inner and outer tubes. After passing through the heat exchange element the treated liquid passes through the debubbling chamber and then through the device outlet. A bypass passageway in the vicinity of the treated liquid inlet to the device connects the debubbling chamber with the space between the inner and outer tubes of the heat exchange element. A valve movable into open and closed positions is provided in this bypass passageway.

Abstract: A heat exchanger with straight tubes for convenient cleaning and repair is constructed with superior heat exchange capabilities. The heat exchanger has an outer shell with a fluid entry and exit and end plates which support one or more tubes with a fluid entry and fluid exit for each tube, the tubes having both an internal turbulence inducing structure and an external fin structure with periodic baffles for maximizing the heat exchange surface area and the contact of the exchange fluids with the exchange area.

Abstract: A reactor, especially for exothermic reactions like methanol synthesis, comprises a tube bundle in which the coiling tube extends through a body of particles to facilitate the discharge of depleted particles from the catalyst space and to increase the pressure resistance of the assembly, the tube sheet at the opposite ends of the bore being convex inwardly. The tube bundle has a helical configuration and the tube sheets are hemispherical in shape in the region where the tubes intersect with the tube sheet. The tubes intersect the bottom tube sheet in radial rows of openings wherein the rows are spaced to facilitate the discharge of catalyst particles.

Abstract: A flash boiler or steam generator includes a shell defining a combustion chamber. A coil bank is mounted adjacent to the combustion chamber and includes an inner coil defining a heat absorption chamber. An intermediate coil is positioned in the chamber surrounding the inner coil. An outer coil surrounds the intermediate coil. The outer coil is in serial communication with a source of fluid and with the inner coil. The inner coil is in serial communication with the intermediate coil and the intermediate coil communicates with an outlet. To limit pressure drop through and increase heat transfer by the coils, the diameter of the inner coil is larger than the diameter of the outer coil and the diameter of the intermediate coil is larger than the diameter of the inner coil. To further increase the heat absorption efficiency of the coil bank, an extended surface is defined on at least a portion of the outer coil.

Abstract: An evaporator for eliminating water from liquids or for cooling liquids by direct expansion of a refrigerant fluid, comprising at least three frusto-conical jackets which include an outer jacket, an inner jacket, and at least one intermediate jacket. Said jackets are coaxially superimposed so as to define annular spaces therebetween. The ends of the jackets are closed except the small end of the internal jacket, which is open and communicates with a chamber defined inside the inner jacket. Inlet and outlet means for a first fluid are connected with respective ends of the annular space between the outer jacket and the adjacent intermediate jacket, and inlet and outlet means for a second fluid are connected respectively to the large end of the annular space between the inner jacket and the adjacent intermediate jacket.

Abstract: A condenser including a condenser chamber having an extension portion extending through the base of a refrigerant storage vessel. The length of the conduction path along this portion is variable. This may be performed by partial retraction of the extension from the vessel, or by inclusion of one or more insulating shields. Both extension and shield may be threaded. The vessel may be of thin stainless steel or compliant solid insulating material, allowing fine adjustment of the conductive path length by tightening of the shield against the base of the vessel. The internal surface of the chamber may be undulated, in particular by threading, to promote turbulent flow and mixing within the chamber. The extension may be recessed and joined to a filling tube, to facilitate initial cool down. The complete condenser is encased by expanded polyurethane foam inside a box.

Abstract: A vaporizer for converting liquid fuel into fuel vapor wherein an annular chamber defined by inner and outer walls is provided and wherein rings are situated one after the other along the length of the chamber, each ring extending around the circumference of the chamber in contact with the inner and outer walls and including a passageway for conveying fluid and/or vapor between the liquid/vapor flow spaces situated on opposite sides of the ring.

Abstract: A window washer system for a motor vehicle is disclosed wherein means are provided for warming the window washer liquid. The window washer system includes a tank (5) for storing window washer liquid, a washer liquid pump (6), washer liquid hoses (7), a flexible heat exchanger tube (8) wound around an engine coolant hose (3), and window nozzles (10). As washer liquid is pumped through flexible heat exchanger tube (8), the washer liquid is warmed by heat conducted from hot engine coolant through the walls of coolant hose (3) and through the walls of heat exchanger tube (8). The heat exchanger tube (8) is connected by coupling elements (9) to the washer liquid hoses (7) in line between the washer liquid pump (6) and the window nozzles (10). The heat exchanger tube (8) is preferably made from a thermoplastic material such as nylon. An ear (15) may project from the side of the coupling element (9). The ear (15) has a small slit (16).

Abstract: The oxygenater heat exchanger disclosed utilizes a heat transfer tube having several tube legs arranged in closely spaced, parallel relation. A resilient central core fits resiliently within the tube legs and cooperates with spiral ribs on the tube and with the housing to form blood flow spiral passages down around the exterior of each of the tube legs. The blood inlet is positioned to enhance efficient heat exchange.

Abstract: The heat exchanger has a hollow coil through which a liquid is to flow, having a series of adjacent, essentially parallel turns, between which turns members having apertures for the flow of a fluid therethrough, elongated heat conducting paths and in compressed and deformed condition are disposed, for clamping contact with the turns and pressure contact with each other. Examples of such members are woven mesh having strands and expanded metal foil. The members extend across the space encompassed by the turns and thus conduct heat between the turns and a fluid passed through the mesh members in the direction of the axis of the coil, i.e. perpendicular to the planes of the coil turns. The members and coil turns are maintained in compressing contact by a perforated plate at each end of the coil, which plates engage the adjacent members.

Abstract: A machine for manufacturing ice including a plurality of elongated vertical tubes of uniform internal cross-sectional dimensions, a cylindrical shell for each tube of length less than the tube and surrounding a substantial portion of the length of the tube, the internal nominal diameter of the shell being greater than the maximum external cross-section dimensions of the tube, the shell having a spiral groove formed in the cylindrical wall thereof, the depth of the groove being such that the interior surface of the shell at the groove contacts at least part of the exterior surface of the tube thereby forming a flow path in the annular area between the exterior of the tube and the interior of the shell which is, at least in part, spiraled. Refrigerant gas is expanded in the tube-shell annular areas to chill the tubes. Water is introduced into the upper end of the tubes to flow downwardly through them and form in each tube a rod of ice.

Abstract: The invention relates to an apparatus for drying finely particulate solids in a carrier gas stream conducted along a helical path. The apparatus consists of an externally heated and cooled flow tube centrically surrounding a similarly heated and cooled inner body. Guide means helically arranged in succession in the flow direction are situated between the flow tube and inner body, and are formed as aerofoil-like curved or flat plates and are distributed over the whole length of the inner body. These guide means are designed as a self-supporting structure not secured to the inner body.

Abstract: A fluid heater, particularly for heating paints, lacquers, varnishes and other spray coating material, includes an elongated hollow tube adapted to be inserted into a fluid flow line for fluid flow through the tube. An electric resistance heater is disposed within the tube and is surrounded by a helical coil member to create a helical fluid flow path through the tube. A temperature control system for regulating the operation of the heater is provided and includes a temperature sensing probe comprising a temperature responsive resistance element enclosed in a conical housing extending into the helical fluid flow path and having its apex contacting the heater and its conical surface area increasing in a direction away from the heater and extending across the cross section of the fluid flow path.

Abstract: A heat exchanger for simultaneously vaporizing a hydrocarbon fluid and water to produce a hydrocarbon fuel gas and steam includes a body member with a smooth surface axial bore having an enlarged end. The non-enlarged portion of the bore receives an elongated thick-walled sleeve having two separate coextensive, interjacent, helical passages formed in its outer surface and positioned in liquid tight engagement with the inner surface of the bore. The first passage communicates with a water inlet and steam outlet at opposite ends of the body member. The second passage is of larger in cross section than the first and communicates at one end with a hydrocarbon fluid inlet on the body member adjacent the water inlet and at its other end with the enlarged bore portion, the latter having a hydrocarbon fuel gas outlet.

Abstract: A vent condenser that includes an inner tube, an outer shell mounted on and surrounding the inner tube, a middle shell having an annular body and a closed upper end mounted with the body thereof radially spaced between the inner tube and the outer shell, and a helical heat exchange tube mounted in the space between the inner tube and the middle shell in engagement with the body of the middle shell and with the inner tube. A helical channel is formed between the middle shell, the inner tube, and spaced convolutions of the helical tube. Cooling fluid is directed through the helical tube. Discharge from the deaerator vent passes up the inner tube to return along the helical channel to be cooled in indirect heat exchange relation with the cooling fluid in the helical tube to condense water therefrom and to separate the water from noncondensable gases.

Abstract: A fluid heater for heating high solids fluids having a solids content approximately 50% or higher, which fluids are applied to a substrate by a coating process, includes a cylindrical body of thermally conductive material having a helical channel formed on the outer periphery thereof and including a section member dividing the channel into a pair of side-by-side passages, each having a cross-sectional area of about 0.119 square inches and a length of about 80 inches. A common input plenum identical in size to the cross-sectional area of the channel communicates with one end of each of the passages and the other end of the passages are connected to a common output plenum. An electric heating element is located in said body along the central axis thereof and is sized to produce a watt density on the surface of said passages in the range of 7.5 to 8.0 watts per square inch whereby the high solids fluids are heated for ease in application with a minimum loss of fluid pressure upon passing through the heater.

Abstract: This invention provides a heat exchanger, particularly useful for systems requiring cooling of hot particulate solids, such as the separated fines from the product gas of a carbonaceous material gasification system. The invention allows effective cooling of a hot particulate in a particle stream (made up of hot particulate and a gas), using gravity as the motive source of the hot particulate.In a preferred form, the invention substitutes a tube structure for the single wall tube of a heat exchanger. The tube structure comprises a tube with a core disposed within, forming a cavity between the tube and the core, and vanes in the cavity which form a flow path through which the hot particulate falls. The outside of the tube is in contact with the cooling fluid of the heat exchanger.

Abstract: A multitubular once-through boiler which exhibits an excellent heat transfer efficiency and requires a relatively smaller installation area. The multitubular once-through boiler comprises a combustion device, a ring-shaped upper header which functions as a vapor chamber, a ring-shaped lower header which functions as a water chamber, a plurality of vertical water-tubes connecting the upper and lower headers to form a single-row ring-shaped water-tube wall, a combustion chamber which is a cylindrical inner space surrounded by the water-tube wall, and a ring-shaped combustion gas passage formed between the water tube wall and an outer wall of the boiler. The water-tubes each has a spiral channel grooved on the surface thereof and is in contact with adjacent water-tubes. The area next to each two adjacent water-tubes, on the side of the tubes facing the outer wall of the boiler, has a barrier plate disposed in contact with the water tubes.

Abstract: Device useful as a heat exchanger for blood or as an apparatus in which blood may be treated or reacted with selected reactants. Device comprises hollow tubing which has plastic monofilament placed in a generally spiral configuration around its outer surface, said monofilament being in the form of continuous or discontinuous projections or ridges. Strands of wire may be substituted for the plastic monofilament. Hollow tubing having such plastic monofilament or strands of wire is also included.

Abstract: A compact multiple coil heat exchanger having a high heat transfer density is provided to include at least an inner coil formed from a continuous tube into a plurality of contiguous turns about a common axis in a spiral arrangement and having a pitch in one direction and an outer coil formed from the continuous tube into a plurality of overlapping turns concentrically about the inner coil in a spiral arrangement having an opposite pitch. Further, a coil-forming apparatus and continuous coil-forming method is directed to form a multiple coil heat exchanger from a continuous tube using a coil-forming die rotatably mounted on a support frame. The coil-forming die includes a continuous spiral thread constructed to receive and laterally support the continuous tube while fabricating the multiple coil heat exchanger according to the continuous coil-forming method of this invention.

Abstract: A steam generating apparatus including a housing defining an inner chamber adapted to receive a continuous supply of water and containing a plurality of elongated heating elements within the chamber for converting the water to steam is disclosed herein. The housing also contains within its chamber a number of spaced plates for supporting the heating elements which extend through cooperating openings in the plates. In order to minimize the accumulation of corrosion material in the crevices around the junctures between the tubes and support plates, a helical groove is provided along the length of each opening around an associated heating element so that water and/or converted steam passing through these openings do so within the grooves whereby to cleanse their crevices of corrosion material.

Abstract: A heat exchanger, especially for the processing of food or pharmaceutical products comprising at least two coaxially superimposed frusto-conical jackets defining an annular space therebetween. Inlet and outlet means for a first fluid are connected to opposite ends of said annular space, and a spacer in the form of a conical helix is freely and releasably disposed in said annular space in contact with the opposite conical surfaces thereof. The spacer and the conical surfaces defining a helical fluid channel leading from the inlet means to the outlet means. Means are provided for releasably attaching the frusto-conical jackets at their large ends and for sealing the large end of said annular space. The first fluid exchanges heat with a second fluid in contact with a surface of one of said jackets contiguous but exterior to said annular space.

Abstract: A gas cleaning and heat transfer apparatus has a plurality of gas cleaning units that concurrently operate to separate foreign matter from the gas and reduces the temperature of the gas. Each cleaning unit has a heat conducting wall surrounding a tubular passage for carrying gas and foreign matter. A plurality of helical elements located in the passage are positioned in angular relationship relative to each other so that the gas moving through the passage is divided into separate helical gas streams. Heat from the gas in the passage is transferred through the wall to the fluid. The jacket around the cylindrical wall has a generally spiral rib in one embodiment which directs the flow of liquid in the chamber in a spiral path. The heating liquid is pumped to a location where the heat in the liquid is utilized. In another embodiment a spiral fin surrounds the heat conducting wall and a relatively airtight jacket surrounds the fin. Air cools the heat conducting wall as it circulates in the jacket.

Abstract: A flue heat reclaimer is constructed to be mounted on the exterior of a flue duct of a heater and provide a spiral-shaped heat transfer passage extending around the flue duct. A fan causes air to flow through the heat transfer passage so that the temperature of this air is elevated by reason at its extended heat transfer relationship with the flue duct.

Abstract: Double walled tube assemblies to meet local code requirements for heat exchangers passing potable water therethrough in non-contacting heat exchange relation for example refrigerant to liquid heat exchangers for reclaiming heat from refrigeration cycles and systems have a first or outer tubular member for passing a first fluid such as hot compressed refrigerant gas therethrough and a second or inner tubular member connected for operative relation to the first tubular member for passing the potable water to be heated therethrough. The second or inner tubular member shaped, sized, and connected to the first or outer tubular member to establish optimum heat exchange relation between the first tubular member and the second tubular member when formed into heat exchange units.

Abstract: A cooling radiator having a secondary cooling means and comprising a pair of spaced liquid coolant tanks, one of which is an inlet tank having a liquid coolant inlet adjacent one end and the other of which is a liquid outlet tank having an outlet adjacent its corresponding opposite end, interconnecting spaced coolant tubes between the tanks, a heat exchanger for cooling a second liquid such as engine oil located in the outlet tank with the heat exchanger having a spaced inlet and outlet and a confined liquid space therebetween for flow of this second liquid through this spaced and an internal fin within the heat exchanger located within an inner tube of the heat exchanger in heat exchange relationship with the liquid coolant in the outlet tank.

Abstract: A gas cleaning and heat transfer apparatus associated with a cooking hood assembly to separate foreign matter from gas moving through the hood assembly and transferring heat from the gas to a liquid. The apparatus has a plurality of gas cleaning and heat transfer units. Each unit has a heat conducting wall surrounding a tubular passage accommodating a plurality of helical elements that divide and direct the gas into separate helical gas streams. A spiral ribbed jacket having a liquid accommodating a chamber surrounds the cylindrical wall and directs the flow of a liquid in the chamber in a spiral path. The foreign matter is separated from the gas as it moves in the spiral path through the passage by the combined mechanisms of centrifugal force, adhesion, condensation, and impaction. The liquid surrounding the wall lowers the temperature of the gas adjacent the inside of the wall causing condensation of vapors carried by the gas on the wall.

Abstract: A device for heating liquid for one or several washer systems.The present invention relates to a device for heating liquid for one or several washer systems, e.g. a wind screen washer system, a head lamp washer system, a rear screen washer system, etc, including a heat exchanger, preferably connected into a return pipe from the engine of a car to the cooling system of the engine.An object of the present invention is to accomplish a device for heating of washer liquid with high efficiency although a very simple design.

Abstract: A heat exchanger apparatus has a center pipe and an outer pipe formed with spiralling grooves attached to the outside of the center pipe. The outer pipe grooves are pressed against the center pipe to form a spiralling passageway around the center pipe between the center pipe and outer pipe. The center pipe has spiralling grooves co-acting with the outer pipe spiralling grooves so that a portion of the outer pipe grooves fit in the center pipe's grooves. Fluid passing through the center pipe has a predetermined turbulence created therein. Cooling fins are mounted in the grooves of the outer pipe in contact with the groove walls to remove heat from both the center pipe and the outer pipe. Special end couplers are provided for connecting the end of the heat exchanger to a liquid input or output for both the center pipe and the outer pipe separately. A coupler for connecting abutting heat exchange units connects the center and outer pipes separately to make longer lengths.

Abstract: A heat exchanger jacket having a substantially tubular body portion is adapted to surround portion of a fluid containing pipe. Two fluid conduits on opposite sides, and connected adjacent opposite end portions, of the body portion lie non-radially in relation to the body portion and may be formed and connected in such a manner as to impart a turbulent swirling or helical path to fluid passing through the body portion.

Abstract: A solar liquid-to-liquid heat exchanger, method of making the same, and hot water heating apparatus employing same are provided wherein such heat exchanger is comprised of a first tubular member made of a heat conductive tube material and having a plurality of turns, a second tubular member made of a heat conductive tube material and having a plurality of turns which correspond to and are fixed against the turns of the first member to provide a strong mechanical and thermal connection between immediately adjacent faces of associated member turns. The fixing of the turns of the members and utilization of the heat exchanger in a hot water heating apparatus with flow of a solar fluid used in such apparatus in one direction through the first tubular member and water to be heated through the second tubular member in counterflow to the one direction assures optimum transfer of heat from the solar fluid to the water to be heated.

Abstract: For a shower for a household, dormitory or the like, which typically has a limited volume of boiler-heated water available for use, the cold water input to the shower is passed in heat exchange with the discharging tepid water to thereby convert same to a lukewarm water source, the temperature change being typically a 15 to 25 degree rise, whereby significantly less boiler-heated water is required for preparing a suitable tepid water mixture confortable for showering. The aforesaid significantly prolongs the showering service use of the system and, since less boiler-heated water is consumed, correspondingly lessens the fuel consumption of the boiler.

Abstract: A coaxial tube in tube heat exchanger has at least one fluid tight connection for holding the outer tube, inner tube and a terminal connector in assembled position, and a support insert fixedly disposed in the inner tube for operative alignment with the fluid tight connection to permit use of a relatively thin walled inner tube for said heat exchanger.

Abstract: A heat exchanger for installation on the top of a chimney of a building includes a housing having a lower end receiving the top of the chimney and an upper end with openings permitting the escape of effluent from the chimney and a heat exchanger assembly disposed in the housing including a central chamber and a spirally arranged duct network defining an effluent spiral path between the top of the chimney and the central chamber and a fresh air spiral path between an inlet disposed at the lower end of the housing and the central chamber, the effluent and fresh air spiral paths being in heat exchange relationship such that air passing through the fresh air spiral path is heated by hot effluent gases passing upward through the chimney and the effluent spiral path for use in heating the building.

Abstract: An apparatus for raising a liquid to a given temperature and for controlling and regulating this temperature has a vertical cylindrical enclosure, a vertical tube housing a heating resistor, and a first and a second ferrule located in this order between the tube and the enclosure to define a first, a second and a third annular space. The first ferrule is connected to the lower wall of the enclosure. The tube and the second ferrule are connected to the upper wall of the enclosure. The liquid is supplied to the lower portion of the first space and extracted from the upper portion of the third space. The length of the resistor is shorter by at least one quarter of the height of the tube and orifices in the lower portion of the first ferrule produce a thermosiphon effect between the first and second annular spaces.

Abstract: A heat exchanger formed by concentric, spaced tubes defining a substantially annular chamber therebetween. There is an internal metallic fin comprising a strip of corrugated sheet metal extending spirally within the annular chamber with the adjacent turns of the spirally formed strip being spaced from each other to provide a spiral passageway between the side edges of adjacent turns. The metallic fin corrugated sheet metal strip bears a plurality of small apertures to significantly improve the boiling heat transfer coefficient.

Abstract: A heat exchanger comprising an elongated tubular housing having an inlet at one end and an outlet at its other end is secured around and spaced from the furnace flue by a plurality of plates secured around the furnace flue. The plates are provided with apertures to permit air flow past the plates. The apertures in each plate are angularly displaced with respect to the apertures of an adjacent plate such that the air circulates around the furnace flue as the flow continues from the inlet to the outlet of the elongated housing. An air pump produces a flow of pressurized air into the inlet of the housing to create a flow of pressurized air through the housing from the inlet toward the outlet of the housing.

Abstract: A planar electrode (17) having a plurality of concentric channels (34--34) therein through which coolant fluid passes to cool the electrode during a plasma etching process. The coolant is directed through at least two of the adjacent channels in opposite directions with the inputs (31) and outputs (32) located in close spaced relation to one another to provide a substantially uniform temperature on the surface of the electrode proximate thereto.

Abstract: A heat exchanger preferably having spirally shaped cooling passages is described. The heat exchanger has the walls of the cooling passages formed first by two jaws spaced apart. The ends of the jaws are then joined together to form the fluid passage. The cooling passage is therefore integral with the base body.