Abstract: An annular flow concentric tube heat exchanger for heating two counter flowing fluid streams has been devised. Although capable of heating gases or liquids, the primary purpose of the invention is to function as an improved recuperator for recovering exhaust heat from a Brayton Cycle gas turbine engine, Ericsson Cycle engine or similar recuperated engine. The basic element of the recuperator is a concentric tube assembly that, in the preferred embodiment, is comprised of four concentric tubes that enclose three concentric annular flow passages. The low pressure exhaust flows through the inner and outer annular passages while the high pressure compressor exit air flows through the annular passage that is between the two low pressure passages. The high and low pressure flows are in opposite directions to achieve the high effectiveness that is only available with a counterflow heat exchanger.

Abstract: A plastic heat exchanger which is simple and inexpensive. The heat exchanger includes an outer duct and a stack of inner ducts, the inner ducts for establishing a first flow path for cooling air or air to be cooled. Each inner duct includes end portions which are stackable upon one another and a middle portion which has a reduced dimension. A seal is placed about each stack of end portions and a second flow path for cooled air or cooling air is formed within the outer duct, between the seals and around the outside of the middle portions of the inner ducts.

Abstract: A combined component consists of a heat exchanger and of a reactor. The heat exchanger is designed in a plate form, and flow spaces for a first medium and a second medium are alternately between successive plates. The plates of the heat exchanger are configured as essentially annularly. The heat exchanger has, substantially perpendicularly to the plates, a tubular outer wall and a tubular inner wall. The reactor is surrounded by the inner wall of the heat exchanger. The product of the reactor is conducted through supply orifices on the inner wall of the heat exchanger into the flow spaces for one of the two fluids in the heat exchanger.

Abstract: Apparatus and method for condensing moisture from an air stream. The condensing comprises concentric cylinders having a common wall. The outer cylinder contains a cooling material, such as water, and upon contact therewith, the air stream is cooled and moisture contained therein is condensed.

Abstract: A tube and shell heat exchanger having a transversely oriented inlet port and a spirally coiled heat transfer tube contained within an arcuate chamber created by an internal baffle in which the water to be conditioned travels along a helical pathway in which the flow has minimized water depth and high turbulence. The tube and shell heat exchanger maximizes heat transfer capability in a relatively easy to assemble design to make feasible the use of a higher cost material for the tubing such as titanium in a wide range of applications.

Abstract: The freeze-protected heat exchanger comprises a fluid supply header for receiving a pressurized heated fluid and a drain chamber coextending with the fluid supply header for collecting and draining cooled fluid. A plurality of heat exchanger tubes extends radially from the fluid supply header and drain chamber, and each comprise outer and inner pipes. The outer pipe has a heat-conductive wall, a proximal end in fluid communication with the drain chamber and a distal closed end. The inner pipe is disposed coaxially within the outer pipe, has a proximal end in fluid communication with the fluid supply header and comprises a plurality of first orifices through which the inner pipe is in fluid communication with the outer pipe. At least one second orifice through which the drain chamber is in fluid communication with the fluid supply header opens in the drain chamber.

Abstract: An improved evaporator for a refrigeration system to reduce the temperature of a medium therein in which a first tube composed of a first material having a first thermal conductivity is surrounded by a body of a second material disposed in intimate contact therewith, the second material having a different thermal conductivity than the thermal conductivity of the first material. An evaporator refrigerator inlet and outlet are disposed in the body and a refrigeration path intermediate the inlet and outlet includes a plurality of fins in the path to increase the surface area of the second material in the path. A refrigeration system using the improved evaporator and including a subcooler, is described and a method of manufacturing the evaporator is disclosed.

Abstract: A gas condensing and cooling system for cooling hot vaporous emissions from a hot vaporous emissions source to a level below prescribed regulatory limits that includes a cooling unit that operates using a readily available pressurized natural gas as the refrigerant element within the cooling unit and includes a multi-chamber condenser unit having a number of chambers each containing a volume of porous rock suspended above a liquid barrier.

Abstract: A heat exchanger element comprises an outer tube (11), an inner tube (12) within the outer tube and a first fluid flow path for a first heat exchange fluid formed between the inner and outer tubes. A second heat exchange fluid is in heat transfer relation to the outer surface of the outer tube and/or the inner surface of the inner tube. A sleeve (13) is provided within the first fluid flow path between the inner and outer tubes. The sleeve defines an outer interface (16) with the inner surface of the outer tube and an inner interface (14) with the outer surface of the inner tube. Generally longitudinal grooves (16,17) are provided at each interface to provide together the first fluid flow path.

Abstract: An apparatus for cooling and warming pole-mounted electronics includes a hollow pole having an upper portion capable of supporting the electronics and a lower portion supported by the ground. An air duct is disposed within the hollow pole such that the hollow pole and the air duct are substantially concentrically aligned about a central longitudinal axis, creating an annular air conduit between the air duct and the hollow pole. A circulating fan is fastened in the lower portion of the hollow pole above ground level. In cooling operation, warm air is drawn downward from the electronics through the air duct, cooled below ground level, and returned via the annular air conduit. The shape of the hollow pole is selected such that at a particular orientation of the sun, the ratio of the shaded surface to the illuminated surface is greater than one.

Abstract: The present invention concerns a heating device for motor vehicles comprising a heat exchanger with primary and secondary circuits. The said exchanger is connected, through a system of ducts to the passenger compartment of the vehicle and/or to the front and/or the rear windows of the same. The said device is intended to heat the said passenger compartment and/or to de-ice the said front and/or rear windows. Under the invention, the said heat exchanger (3) is placed at the engine (M) exhaust of the said vehicle (1). The exchanger (3) primary circuit (12) is on the one hand, connected to the outlet of any cylinders (C) of the engine (M) so as to be crossed by the exhaust gases from the latter and, on the other hand, it is connected to the manifold (13) leading to the muffler.

Abstract: A wall structure for fuel-cooled engine walls, with a cooling structure having an inner wall to which hot gas is admitted; an outer wall located at a spaced location therefrom; as well as a plurality of webs, which connect the two walls and divide the intermediate space between the walls into cooling channels (19), and with a support structure in the form of at least one stable outer jacket. The cooling structure is slotted from the outside in the area of each web, wherein the slots (22) pass through the outer walls and the centers of the webs into the area of the inner wall. The support structure is designed as an elastically nonrigid support structure at least in the area joining the cooling structure and/or is located at a spaced location from the cooling structure.

Abstract: A heat exchanger system including an outer duct housing a powered fan at one end. A heat exchanger is positioned in line with the fan within the duct and includes two nested pipes. Each pipe includes radially outward fins and radially inward fins. The radially inward fins on the outer pipe and the radially outward fins on the inner pipe are interdigitated. Appropriately positioned radial dividers extend fully between the bodies of the two pipes to divide the space between pipes into segments. End caps placed on the ends of the pipes include baffles which appropriately divide annular manifolds defined between the pipes and between the ends of the fins and the end caps in order that four passes are possible through the length of the heat exchanger. The radial dividers may be asymmetrically positioned to accommodate changes in volume with condensation of the fluid passing between the inner and outer pipes.

Abstract: A heat exchanger and heat pump circuit having an operating subcircuit and a pump down subcircuit each including a liquid line and a heat transfer tube. The heat transfer tube of the pump down subcircuit surrounds the liquid line of the operating subcircuit. During the heating cycle, the heat pump circuit circulates refrigerant through both subcircuits to abstract heat from the heat source/sink. However, during the cooling cycle, the heat pump circuit circulates refrigerant only through the operating subcircuit. Also during the cooling cycle, the heat pump circuit places the pump down subcircuit at low pressure to thermally insulate the operating subcircuit liquid line.

Abstract: An annular heat exchanger for incompatible fluids, such as reactive compounds, particularly for the aeronautics industry, in which a sealed bottle is fixed interior of a hollow body, with integral heat dissipators and novel fluid passageway orientation, whereby no leak can occur which would commingle the incompatible fluids.

Abstract: A smoke generator apparatus (10) is disclosed which is suitable for use in conducting air flow studies in wind tunnels. The smoke generator apparatus (10) includes a tube assembly (12) which may either be wire-packed or crimped and has fluid flow and heat transfer characteristics which permit the substantially uninterrupted flow of smoke-appearing vapor (82) from the tube outlet (52).

Abstract: Multi-passage heat exchange element which includes an elongated central first fluid passage for passage of a first fluid of a heat exchanger, a plurality of substantially helically convoluted second fluid passages for a second fluid of a heat exchanger, the second fluid passages substantially helically surrounding at least a portion of the elongated central passage, and a plurality of substantially helically convoluted first fluid passages for passage of the first fluid of a heat exchanger, the first fluid passages substantially surrounding at least a portion of the second fluid passages.

Abstract: The present invention relates to one or more ground tubes connected and channelized to provide a counter-flow heat exchanger with an annular space to permit water injection into the subsurface water table.

Abstract: A single port, internal liquid heat exchange assembly for heating domestic water from a free-standing, low pressure wood fired boiler. A threaded manifold fastener retains the assembly in suspension within a single access port of a conventional water heater. An elongated manifold contains first and second coaxial flow columns which terminate at exposed inlet and outlet ports and communicate with each other within the manifold. Constructions are disclosed having concentric flow columns, convolute and expandable manifold walls, internal bypass ports, vibration dampeners, multi-ported flow transition zones and which may include a sacrificial anode.

Abstract: A gas trap apparatus is disclosed for trapping gaseous fraction of mixtures. The apparatus includes a gas column chamber into which a tubular column, such as a capillary tube, may extend. A cooling chamber is provided into which a coolant may be introduced for solidifying or liquefying a gas sample. A heating element in surrounding relationship to the cooling chamber is used for vaporizing the solidified/liquified gas. A Dewar flask surrounds the gas trap apparatus to prevent thermal leakage to the atmosphere.

Abstract: A sanitary concentric tube heat exchanger for cooling or heating flowable or pumpable products is disclosed. In one embodiment, two concentric tubes are sealed together with inlet and outlet openings. The product is allowed to flow through the outer of the two tubes while the heating or cooling medium flows through the inner tube. In another embodiment, a third concentric tube surrounds the product tube and is used for the flow of additional heating or cooling medium. A securing clamp open on one end of the product tube secures the product tube to the outer surface of the inner tube and can be easily dismantled for cleaning purposes. A seal assembly secures the other end of the product tube to the outer surface of the inner tube and permits relative movement between the inner tube and the product tube for accommodation of thermal effects during operation, and also to allow the asembly to be easily dismantled for cleaning or inspection.

Abstract: A heat exchanger suitable for processing fruits, vegetables and other agricultural products and particularly tomatoes. Agricultural products to be heated are first triturated, cut, mashed or otherwise crushed and then passed through one or more product passageways in the heat exchanger. Steam is passed through one or more heating fluid passageways separated from, but in close heat exchange relationship with the product passageway. In order to attain high heat transfer from the steam to the agricultural product, the distance from the heating fluid passageway to the product in the product passageway is kept to a practical minimum. The product passageways are configured to accommodate large foreign objects such as twigs, pieces of plant, weeds and the like which are frequently included in the stream of triturated agricultural product.

Abstract: An end manifold (2) for a concentric tube heat exchanger, the end manifold being especially suitable for treatment of viscous fluids. The end manifold has an obliquely oriented shoulder (38) which serves to direct the viscous fluid into an outlet port (30) so as to avoid stagnant regions of the viscous fluid which would be otherwise subjected to overheating. The same manifold can be used at the inlet end as well as for cooling purposes and allows for more effective cleaning when a cleaning fluid is circulated therethrough.

Abstract: An improved air dryer for pneumatic systems (10). The improved air dryer (10) employs air-to-air and an air-to-refrigerant heat exchanger portions (12-14) that are substantially parallel and coextensive. Each heat exchanger portion (12-14) is made up of a plurality of tube units (16-52), each tube unit (16-52) having three concentric tubes (22-24-26-58-60-68). The intermediate tube (60) of the air-to-refrigerant portion (14) includes a helically deformed central portion (66) to increase surface area and create turbulence within adjacent passageways (70-74). The tubes (16-52) terminate at each end in separate header units (34-40-46-80-86-92). Incoming air is passed co-currently, then countercurrently, in the-air-to-air portion (12) with air that has been dried, whereupon a pre-cooling stage is achieved. This pre-cooled air is then passed counter-currently, then co-currently, to refrigerant in the air-to-refrigerant portion (14) for causing condensation of moisture therein.

Abstract: A double pass tandem cooling aerosol condenser apparatus for receiving aerosol from a liquid solution for a specimen sample which has been prepared for injection into an inductively coupled plasma associated with an emission spectra or mass spectrometer comprises inner and outer compartments for circulating a coolant therethrough. The aerosol, comprising solvent and analyte particles, is passed through compartments of the condenser which are interposed between the inner and outer coolant compartment. The temperature of the aerosol compartment is adjusted and controlled such that the solvent particles, which would otherwise quench the inductively coupled plasma, are condensed and stripped from the aerosol leaving a relatively stable, dry aerosol containing the desolvated analyte particles for spectrometric analysis.

Abstract: A heat exchanger with two concentrically disposed corrugated tubes nested one within the other for the flow of two separated fluids through the exchanger. Each tube has convolutions, and fluid openings or passageways exist for directing flow completely through each convolution of each tube for optimum heat exchange. Endplates are provided on the exchanger for assembly, and also for ease of repair and cleaning of the exchanger. The arrangement of the convolutions and openings is such that a cardioid flow pattern is obtained for the maximum efficiency of heat exchange.

Abstract: A heat exchanger for an internal combustion engine includes a first conduit, a second conduit positioned outside of the first conduit, a third conduit positioned inside of the first conduit, a first annular passage formed between the first and second conduits, and a second annular passage formed between the first and third conduits. Heat exchange is performed between a first fluid flowing through the first annular passage and the inside of the third conduit and a second fluid flowing through the second annular passage.

Abstract: A corrosive and errosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is conveyed through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium.

Abstract: A plurality of coaxially arranged, nested tubes (1, 2, 3, 4) are retained between distributor heads (8, 45). The heads and the outermost tube (1) are coupled to one another in a media-tight manner by fitting flanges to provide releasable axial connections. Each distributor head (9, 45) has two walls (9, 10, 46, 47) concentric to one another as well as one end chamber (17, 50) communicating with an annular chamber (11, 48, 49) formed between the walls. The outer wall (9) is joined to the outer tube (1), and the second tube (2), located inside the outer tube, is inserted into the inner wall (10) against an axial stop (24). A sleeve (26, 58, 59) is connected to a third, inner tube (3) located inside the second tube (2). The sleeve (26) is also braced against an axial stop (28) of the inner wall (10) close to the end chamber. The interior (34) of the sleeve communicates via an opening (19, 55) with the end chamber (17, 50).

Abstract: The heat exchanger, which forms a part of the fluid treatment apparatus of this invention, includes an insulated tubular having concentric telescopically nested spaced tubes, wherein the space between the tubes is sealed and filled with an inert gas. The surfaces of the tubes are coated with a hydrogen permeation barrier preferably comprising an aluminum-iron alloy, nickel or copper which limits atomic hydrogen permeation into the space between the tubes, which would combine to form hydrogen gas and result in heat loss. The insulated tubular is telescopically nested in a pipe, forming a fluid heat exchanger and the heat exchanger is telescopically nested in fluid waste circulation pipes, forming the fluid treatment apparatus of this invention. The preferred fluid heat exchanger is a vertically extending deep well reactor suitable for wet oxidation reaction of fluid wastes including municipal sludge.

Abstract: A solar energy system for heating water. The system comprises a solar collector, a heat exchanger, and hot water storage tank along with necessary interconnecting conduits, circulating pump and controls. The system is characterized by a double-walled fluid heating conduit within the solar collector and by a triple-walled heat exchanger housing enclosing three concentric liquid passageways. Liquid heated by the solar collector is circulated through the outermost and innermost heat exchanger passages while water to be heated is circulated in countercurrent flow through an intermediate passageway sandwiched between the other passageways.

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

Abstract: A heat exchanger for heating air supplied to a burner is described. The heat exchanger includes two passages. One of the passages provides a channel through which combustion gas is exhausted from the burner while the other passage provides a channel through which air is supplied to the burner. The two passages are arranged to transfer heat from the combustion gas to the combustion air. Each of the passages includes a helical guide baffle for directing fluid through each respective passage substantially along a helical flow path. The helical guide baffles of the passages each exhibits a variable pitch which changes at a predetermined rate to maintain the pressure and velocity of the fluid in the respective passages within predetermined limits.

Abstract: The present invention relates to a heat exchanger which is specifically adapted for use in connection with blood oxygenators, particularly bubble oxygenators. The core of the heat exchanger is generally cylindrical and closed at both ends. The cylinder is made of thin walled material with good heat exchange properties such as aluminum. The portion of the heat exchanger core which will be exposed to blood is coated with a biocompatible material such as tetrafluoroethylene. The heat exchanger may be connected to a source of heat exchange medium, such as water, through couplings in the top portion of the heat exchanger core. The heat exchange medium is then circulated through the core providing heating or cooling which is capable of heating or cooling blood within a bubble oxygenator. The heat exchanger core is then nested within a suitable receiver.

Abstract: Disclosed is an apparatus for extruding thermoplastic compositions comprising an extruder, a die, and a cooling device positioned between the extruder and the die for cooling the heat plastified resinous composition exiting from the extruder to a uniform temperature desired for extrusion through the extrusion die. The cooling device includes at least one enclosed flow path for conveying the resinous composition from the inlet of the cooling device to the outlet of the cooling device, structure for circulating a cooling medium about the entire circumference of each of the resin flow paths, and flow control orifices at the inlet and the outlet of the cooling means across the entire cross-section of each of the resin flow paths.

Abstract: A method and apparatus for drying and/or pre-heating in particular scrap metal with the aid of waste gases deriving from an electric arc furnace. The waste-gases are passed from the electric arc furnace through a line (1,2,3) which is arranged between an external, outwardly insulated container (6) and an inner container (4) for accommodating the scrap metal, with a gap (7,8) located between the waste-gas line and the containers. Air is drawn in through the gap (7,8) and absorbs heat from the wall (3) of the waste-gas line, whereafter the heated air is caused to pass through the scrap (5) in the inner container (4) and to deliver heat to the scrap.

Abstract: A heat exchanger for exchanging heat between two different temperature fluids. The heat exchanger includes a sealed housing having first and second pairs of inlets and outlets. A first conduit is disposed within the housing. A second conduit is concentrically disposed within and spaced from the first conduit to define a first flow path between the spaced wall surfaces thereof which is disposed in fluid flow communication with the first inlet and first outlet for flow of a first fluid in a first direction through the housing. A second fluid flow path including first and second serially connected sections is provided for directing a second fluid between the second inlet and the second outlet over the exterior wall surface of the first conduit and through the second conduit in a second direction opposite to the direction of flow of the first fluid. In a preferred embodiment, a sealed chamber is formed interiorly within the housing about the first conduit.

Abstract: A heat exchanger includes elongated inner and outer tubular members defining an elongated generally annular passage therebetween. A burner mounted adjacent one end of the tubular members discharges hot gases into the inner tubular member for axial flow therealong and entry into the annular passage adjacent the ends of the tubular members remote from the burner. The gases then flow back through the annular passage for discharge through a lateral exhaust outlet in the outer tubular member adjacent the one end thereof. The annular passage has a varying cross-sectional shape along its length such that a major portion of the gases enter the annular passage at a location diagonally opposite from the exhaust outlet and then flow both longitudinally and circumferentially along the annular passage toward the exhaust outlet. The heat exchanger is particularly useful in heating diesel engine coolant to facilitate more rapid engine starting.

Abstract: A heat extractor for picking up waste heat from flue gases is disclosed. The extractor attaches to the stove pipe of a furnace or stove. Air is introduced into the extractor in a spiral flow pattern which is reversed after the air is heated. Air flows into the room from the extractor in a 360.degree. pattern.

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: Disclosed is an apparatus for extruding thermoplastic compositions, comprising an extruder; a cooling device positioned downstream of the extruder for cooling the heat plastified thermoplastic resinous composition exiting from the extruder to a uniform temperature desired for extrusion through an extrusion die, the cooling device including at least one enclosed flow path for conveying the resinous composition from the inlet of the cooling device to the outlet of the cooling device, structure for circulating a cooling medium about the entire circumference of each of the resin flow paths and a device for maintaining a hydraulic balance between the inlet and the outlet of the cooling means across the entire cross-section of each of the resin flow paths; and an extrusion die positioned downstream of the cooling device.

Abstract: A heat recapture device for attachment to a furnace or fireplace exhaust flue is disclosed. Duct work in the device allows ambient air to be warmed by combustion exhaust gases. Air thus heated may be used to heat the surrounding living space. Additional duct work causes circulation of fresh air into the room and serves as a heat insulating shield around the periphery of the device.

Abstract: Apparatus for saving heat which is otherwise wasted particularly in multi-story buildings. The apparatus in one form includes first, second, and third elongated hollow members which are disposed for at least an axial section in coaxial relationship. The first or central elongated member carries smoke and waste heat away from a heating apparatus such as a furnace. The second and third elongated members are in fluid communication with each other. The second elongated member in one form of the invention is also in fluid communication with an air inlet disposed on one floor of the associated house. The third elongated member is also in fluid communication with another floor of the associated house.

Abstract: A heat exchanging apparatus for reducing the temperature of a heating fluid prior to thermal communication with a heated fluid. The apparatus includes an integral pre-cooling heat exchanger located within a main heat exchanger. The pre-cooling heat exchanger brings the heating fluid into thermal communication with the heating fluid circulating in the main heat exchanger so that the heated fluid is prevented from departing from nucleate boiling in the main heat exchanger.

Abstract: A heat exchanger has a modular construction to create uniformity among several of its components. The heat exchanger utilizes concentric tubes, with one fluid flowing through the inner tube, and the other fluid flowing through the annular space in the outer tube. The inner tube fluid flows back over the outer tube, further exchanging heat, as it is discharged. The heat exchanger includes four cup-shaped modules that nest or slide together. Each module includes a sleeve with a port for one of the fluids. Each module also has a convex portion that slides sealingly into an adjacent module and contains holes for the tubes. The tubes are sealed into the holes in the convex portions, causing each module to define one of the four manifolds necessary for the operation of the heat exchanger.

Abstract: Worm extruder assembly includes an extruder worm, a steam dome formed as a cylindrical tube disposed transversely to the worm axis, a condenser surrounding the cylindrical tube, a steam outlet line extending from the steam dome to the condenser, and means defining an annular gap connecting the condenser to the cylindrical tube.

Abstract: An auxiliary heater device comprises a tubular combustion chamber surrounded by a heat exchanger 50 as to define a gap therebetween. The peripheral wall of the combustion chamber is provided with a plurality of circumferential projections that extend into the gap in a manner that reduces direct contact heat exchange between the combustion gases flowing through the gap and the peripheral wall by blocking axial flow of the gases along the wall in contact therewith and by deflecting these gases toward the heat exchanger pipe.

Abstract: This invention is a heat exchanger device which is an improvement on U.S. Pat. No. 3,612,002, Liquid-Heating Apparatus by the same inventor. The invention is a heating or cooling apparatus for liquids which lends itself to quick disassembly and reassembly and which contains a hollow double flange inlet for the introduction of heating medium, a double helix to lead the heating medium inside of hollow concentric cylinders, and a hollow flange with two chambers for the introduction of fluid. In addition, the apparatus is modified by rounding its internal structure to allow coating of its internal surface with a corrosion resistant film such as glass, plastic or the like. A further modification of the invention comprises the construction of cylindrical elements with spiral paths therethrough.

Abstract: A water cooled material additive chute for introducing fluxing material into a furnace including water cooled inlet and outlet chambers meeting at a tip or nose portion, a local coolant water injection pipe extending through one of the chambers and into the tip region to augment the cooling efficiency of the water coolant, and a pipe structure which accommodates thermal expansion.

Abstract: A built-in oil cooler, comprising an outer tube and an inner tube, the latter tube is provided with a plurality of dent and projection portions alternately formed on its surface in axial direction thereof. Said inner tube is inserted in said outer tube to keep its outside face having no dent portion in contact with inside face of said outer tube, forming oil space between both of said tubes. Oil within said oil space flows zigzag to assure very good heat transfer rate.