Abstract: A ceramic recuperator (18) for a recuperator burner (1) is provided, in its heat exchanger region, with a plurality of radially inward- and outward-extending teeth. On the otherwise hollow-cylindrical recuperator (18), the teeth (19) are arranged in groups, e.g., in rings; the teeth of one ring are each offset from the teeth of an adjacent ring. Alternatively, it is possible to arrange the teeth on a single- or multi-start helical line. The recuperator can be produced economically by the slip-casting method.

Abstract: The present invention relates to the formation and use of catalytic materials as a part of or in association with heat exchangers such as automotive radiators and air conditioning condensers. The catalytic material involves a metal substrate with a porous anodic oxide coating and metallic nodules which are electrodeposited in the pores and extend above the surface of the anodic oxide coating. The nodules are either formed of the catalytic metal or formed of other metals and then coated with the catalyst metal. The catalytic stock material is then formed into heat exchanger fins and mounted on the heat exchanger tubes. In the alternative, the catalytic stock material may be formed into a separate catalytic structure which is then mounted in an air flow stream and preferably in air-flow relationship to the heat exchanger.

Abstract: The present invention provides a coating composition for hydrophilization comprising (A) a water-soluble or water-dispersible organic resin, (B) organic resin fine particles described below and (C) a crosslinking agent, and a method for hydrophilization of heat exchanger fins by coating said fins with the above composition. The organic resin fine particles (B) are fine particles having a weight-average particle diameter/number-average particle diameter ratio of 1.2 or less and an average primary particle diameter of 0.1-1.0 .mu.m, which are obtained by dispersion-polymerizing 100 parts by weight of a monomer mixture consisting of 0.1-10.0% by weight of (a) at least one monomer selected from a polyoxyalkylene chain-containing (meth)acrylate and a (meth)acrylamide, 15.0-45.0% by weight of (b) divinylbenzene, 45.0-84.9% by weight of (c) styrene and 0-39.9% by weight of (d) (meth)acrylic acid, in the presence of 40 parts by weight of a poly(meth)acrylic acid in a lower alcohol.

Abstract: An absorption refrigerator uses water as a refrigerant and a halogen compound as an absorption solution, and is characterized in that an oxide film of thickness of 0.02-5.0 .mu.m is formed on a surface of at least one of a heat exchanger and a high temperature regenerator. And a production method of the absorption refrigerator is characterized by oxidizing a surface of at least one of a heat exchanger and a high temperature regenerator at a temperature of 200.degree.-800.degree. C., and adjusting a heating temperature and a heating retaining time so that a value of parameter(P), obtained according to P=T (5+log t) is 3.5-6.0.times.10.sup.3, wherein T represents heating temperature (.degree.K), and t heating retaining time (minute).

Abstract: A heat exchanger, in which a plurality of fins formed on either an internal or an external face of a heat transfer tube, wherein each of the plurality of fins has a first portion including a fin top and a second portion including a fin root, and wherein the first portion has a ridgeline formed in a raised and recessed shape, or in a wave-like or corrugated shape, and the second portion has a substantially straight outline in a fin longitudinal direction in a cross section parallel to either the internal or the external face on which the plurality of fins are formed.

Abstract: A stack type evaporator includes tubular elements 1 each having a plurality of inwardly protruding recessed ribs 7 which extend from an upper header portion 1a of the element to a lower header portion 1b, with the ribs serving as straight drainage canals 7a of specified width and area. A hydrophilic resin coating of a specific composition covers the outer surfaces of the tubular elements 1 and fins 2 each interposed between two adjacent tubular elements. The combination of straight drainage canals, the specified width and area thereof and the specific hydrophilic resin coating is effective to facilitate the drainage of condensed water so that the waterdrop is substantially prevented from flying out of the evaporator, and the hydrophilic coating itself does not emit any unpleasant smell.

Abstract: A heat exchanger, such as a condenser, for use in a automobile air conditioning system includes a plurality of flat tubes for conducting the refrigerant and a plurality of corrugated outer fins fixedly sandwiched between the flat tubes. First and second header pipes are fixedly and hermetically connected to the flat tubes and, thereby, communicate with the interior of the tubes. A plurality of diagonally arranged projected stripes are formed on inner surfaces of the flat tubes. First portions of the projected stripes project from a lower inner surface of the flat tubes, and second portions of the projected stripes project from an upper inner surface of the flat tubes. The first and second portions of the projected stripes are in contact with one another at the points of intersection therebetween.

Abstract: The present invention has the object of increasing the heat exchanging performance of heat transfer tubes having grooved inner surfaces. In order to achieve this object, the heat transfer tubes having grooved inner surfaces according to the present invention have fins which are formed consecutively in a circumferential direction on the inner surface of a metallic tube. The inner surface of the metallic tube is divided into regions R1.about.R4 in the circumferential direction. The inclination angle .alpha. with respect to the axis of the heat transfer tube of the fins 2 in odd-numbered regions when counting from one of the regions is 10.degree..about.25.degree., and the inclination angle .beta. with respect to the axis of the heat transfer tube of the fins 2 in even-numbered regions when counting from the region is -10.degree..about.-25.degree.. The pitch of the fins 2 is 0.3.about.0.4 mm, the height of the fins from the inner circumferential surface of the metallic tube is 0.15.about.0.

Abstract: The invention relates to a metallic heat-exchanger tube (1) with fins (2) which annularly or helically extend or rather extend in axial direction on the outside of the tube for condensing of vapor from pure substances or mixtures on the outside of the tube. To improve the condensation performance by effecting a thinning of a liquid film, the invention includes a making of the fins so that they have a constant fin height H throughout, with the fin flanks (4) being structured by spaced-apart depressions.

Abstract: A heat exchanger assembly including at least one aluminum based tube having an internal surface and an external surface, an aluminum based lithium-magnesium composition cladding applied to either one of the internal surface and external surface of the tube, and at least one aluminum based component disposed adjacent the cladding, a modified aluminum brazing flux applied to a joint between the surface and one component. The modified aluminum brazing flux comprises cesium fluoride, lithium fluoride, or both. Preferably, the cladding further comprises cesium. To manufacture the heat exchanger assembly, the tube and component are joined together with flux applied in the area of the joint using a controlled atmosphere brazing (CAB) process.

Abstract: A heat radiating board and a method for cooling by utilizing the same based on a novel principle of heat gradient. The heat radiating board, which is disposed between a high temperature zone and a low temperature zone, consists of a metal plate and a heat gradient-forming layer laminated on the surface thereof facing the low temperature zone, this heat gradient-forming layer being formed from a heat conductive material having a heat volume and an absorption of heat of radiation smaller than the metal plate.

Abstract: A heat exchanger assembly includes at least one tube having an internal surface and an external surface, a composition cladding having at least lithium and magnesium applied to either one of the internal surface and external surface of the tube, and at least one component disposed adjacent the composition cladding, whereby the tube and component are joined together during a controlled atmosphere brazing process.

Abstract: A method of brazing is described, the method comprising the steps of applying a layer of particles of an aluminum alloy filler material said particles having a coating of a flux-type material selected from the group comprising a compound of potassium fluoride and aluminum fluoride together, or other inorganic flux-type material, to at least one of said articles such that said particles are retained at or adjacent at least a part of the joint between said articles; heating to cause the flux-type material and said aluminum alloy filler material to melt and form a brazed joint.

Abstract: A thermal cycling reaction apparatus comprises a reactor having a reactor body made of a thin heat-conductive plate having a cavity as a reaction chamber with an opening of the chamber sealed with a transparent heat-resistant sheet. The apparatus further includes, delivery rollers for delivering the reactor along a delivery path and stopping it at stopping positions in a predetermined order; plural temperature-controlling blocks having respectively a temperature-controlling surface to be brought into contact with a heat-transfer face of the reactor and being placed at the stopping positions separately so as not to thermally affect each other; and a temperature-controlling mechanism for keeping the fixed temperature-controlling surfaces respectively at prescribed temperatures.

Abstract: Inconsistent and costly corrosion protection with prior art heat exchangers are eliminated in a heat exchanger (10) formed of an aluminum fin (16) clad with an Al--Si--Zn braze clad compound (18), an aluminum tube (14) brazed to the fin (16), and bonded thereto by the braze clad compound (18) with zinc diffused into the tube, whereby the aluminum tube (14) is corrosion resistant by reason of the presence of sacrificial zinc therein.

Abstract: A laminated type heat exchanger includes a plurality of refrigerant passages which are formed by pairs of core plates. Each core plate comprises an outer covering layer, a core layer, and an inner covering layer. The outer covering layer is made of a brazing material of which electric potential is more negative than the core layer while the inner covering layer is made of a brazing material of which electric potential is equal to or more positive than the core layer. The refrigerant passages are formed by brazing only the adjacent two of the inner covering layer. The outer covering layer works as a sacrificial corrosive material with respect to the inner covering layer and the core layer. Leakage of refrigerant from the brazed portions of the core plates is prevented, whereby the corrosion resistance of the laminated type heat exchanger is improved.

Abstract: To prevent with certainty corrosion by mercury even in nonoperating of plant facilities, plate fins 1 and flat plates 2 of flow passage members constituting cooled fluid passages and refrigerant passages are formed by an aluminum alloy and on surfaces of the plate fins 1 and the flat plates 2, an oxide film formed by a reaction between the aluminum alloy and an oxidizing component in an oxidizing gas is formed, or a hydroxide film formed by a reaction between the aluminum alloy and an alkaline component in an alkaline aqueous solution is formed.

Abstract: A heat exchanger having corrosion resistant resin-coated plates and pipes. The heat exchanger is easily constructed using the corrosion resistant resin-coated plates and the pipes. The heat exchanger does not require heat treatments or large constructing sections. In the heat exchanger according to the present invention, a gas is supplied to the outside of pipes, and air and/or water are passed through the pipes. As a result, heat change is accomplished. A pipe plate and a side wall of the heat exchanger are coated with Teflon or a heat resistant resin. In the feed water pre-heater for heating water, pipes are formed as metal pipes coated with a resin for maintaining the strength of the pipes. Thereafter, the pipes are individually welded and fabricated. In the feed air pre-heater, the heat exchanger has side walls, a pipe plate and pipes. The side walls and the pipe plate have essentially the same structure. The pipes are made of resin. The pipe plate and pipes are united by a metal assembling member.

Abstract: Metallic tubes (10,10') for boiling have an outer surface (12) for contacting a refrigerant and an inner surface (14) for contacting a liquid heat transfer medium to be chilled. The outer surface (12) has a plurality of radially outwardly extending helical fins (18); the tube inner surface (14) has a plurality of helical ridges (16). The fins (18) of the outer surface are notched to provide nucleate boiling cavities having pores (30). The fins (18) and notches (N) are so spaced that the pores (30) have an average area less than 0.00009 square inches and a pore density of at least 2000 per square inch on the tube outer surface. The helical ridges (16) on the inner surface have a predetermined ridge height and pitch and are positioned at a predetermined helix angle, the inner surface having a severity factor .PHI. in the range of 0.006 to 0.008.

Abstract: A heat exchanger inner spiral-ribbed tube made of a hard metal such as stainless steel, titanium, or an iron-nickel alloy, and method of manufacture therefor for use in making a heat exchanger. The tube has an annular wall having an inner ribbed surface and an outer waved surface. The inner surface has a plurality of inner spiral ribs, each having a spiral angle. The spiral angle is about 18 degrees in the described embodiment. The tube-making method includes multiple steps in forming the outer waves and inner ribs simultaneously, progressively increasing the rib height while continuously pulling the tube in an axial direction.

Abstract: A heat exchanger tube having a smooth outer surface and a textured inner surface. The inner surface is composed of parallel ribs which run at an angle deviating from 90.degree. relative to the longitudinal axis of the exchanger tube. The ribs further have inclined flanks, channels delimited on the sides by the ribs, and depressions formed in the ribs, which may run crosswise at a distance from the bottom of the channels. The depressions are formed so as to follow a sine-shaped progression, in longitudinal cross-section of the ribs, which are provided with a surface micro-roughness and which are rounded on the top. The center longitudinal planes of the depressions are arranged at an angle deviating from 90.degree. relative to the longitudinal axis of the exchanger tube. The opposite flanks of adjacent ribs are connected by means of rounded channel bottoms. The micro-roughness of the rib surfaces is produced by corundum blasting or laser beams.

Abstract: An evaporator heat transfer tube (10) for use in a heat exchanger where heat is transferred between a fluid flowing through the tube and a fluid flowing around the exterior of the tube and where the fluid external to the tube boils during the heat exchange process. The tube has a plurality of helical fins (20) extending around its external surface (13). A pattern of notches (30) extends at an oblique angle (.alpha.) across the fins at intervals about the circumference of the tube. A spike (22) having a flattened distal tip (23) is formed between each pair of adjacent notches. The maximum width (W.sub.t) of the spike at its tip is greater than the width (W.sub.r) of the base portion of the fin and is of a width sufficient to overlap with and contact the distal tips of spikes in adjacent fins on both sides thereof, thus forming reentrant cavities between the adjacent fins and under the overlapping tips.

Abstract: An improved radiant heat transfer tube with internal fins is provided. Optimum design characteristics for the number of fins, the height or length of the fins and the twist of the fins is provided to enhance convective and radiant heat transfer from combustion gases inside the tube to the inside surface of the tube. The fin design applies to tubes fabricated from high temperature metal alloys, monolithic ceramics, metal matrix composites or ceramic matrix composites.

Abstract: A heat transfer tube for use in a refrigeration evaporator. This tube includes an outer surface with axially spaced bent fins which form and enclose annular tunnels. The bent fins have top edge portions which have peripherally spaced sets of notches of different sizes on the same fin convolution and refill gaps for fluid flow to the tunnels for heat transfer through the annular wall. The concept of placing different pore sizes next to each other on the same fin allows a more efficient use of the tube's surface area for evaporative heat transfer.

Abstract: A heat exchanger, such as a condenser, for use in a automobile air conditioning system includes a plurality of flat tubes for conducting the refrigerant and a plurality of corrugated outer fins fixedly sandwiched between the flat tubes. First and second header pipes are fixedly and hermetically connected to the flat tubes and, thereby, communicate with the interior of the tubes. A plurality of diagonally arranged projected stripes are formed on inner surfaces of the flat tubes. First portions of the projected stripes project from a lower inner surface of the flat tubes, and second portions of the projected stripes project from an upper inner surface of the flat tubes. The first and second portions of the projected stripes are in contact with one another at the points of intersection therebetween.

Abstract: A copper heat exchanger unit for operating in a harsh environment wherein the exposed surfaces of the unit are first provided with a black oxide layer and then electrocoated with a protective acrylic barrier.

Abstract: Heat exchanger has a first surface on which a first fluid flows and a second surface on which a second fluid flows, at least one of the first and second surfaces has at least two projections and a bottom therebetween, and an imaginary line on the bottom along a shortest distance between the projections adjacent to each other is prevented from extending along an imaginary face substantially parallel to a main flow direction of one of the first and second fluids which flows over the bottom.

Abstract: A composite parting sheet is disclosed for separating hot and cold layers in a heat exchanger core. Known parting sheets being primarily aluminum are subject to leakage due to corrosion and failure resulting from thermal fatigue stress. The composite sheet of the present invention includes a first aluminum outer layer, a second aluminum outer layer and a central metallic layer between and in contact with the first and second aluminum outer layers so that the central metallic layer comprises a continuous, uninterrupted layer between the first and second outer layers, and the central metallic layer is a metal that is more noble than aluminum, such as nickel. Corrosion penetrating either of the outer layers to produce a pin hole preferentially corrodes aluminum over the central metallic layer. Therefore, the corrosion expands sideways upon contact with the central metallic layer, and the pin hole does not penetrate the layer or the parting sheet, thereby inhibiting corrosion induced leakage.

Abstract: Heat exchangers for a thermoelectric cooling (TEC) device. A heat dissipation assembly comprises an array of foil corrugations disposed in generally parallel spaced relationship with the heat dissipation plate of the TEC. The array of foil corrugations includes at least an inner and an outer bank of foil corrugations and at least one plate sandwiched therebetween and secured thereto by vacuum brazing thereacross. In this manner, heat conductivity is maximized for transfer of heat thereacross and from the TEC to the outer bank. A heat absorption assembly for use with the TEC comprises a thermal transfer plate having a teflon coated, serpentine fluid conduit therein facilitating the flow of a variety of fluids to be cooled therethrough without contamination thereof.

Abstract: Optionally antimicrobial, hydrophilic coatings having reduced or low solids contents are provided. Such coatings are extremely useful for coating heat transfer surfaces of condensing heat exchangers to provide wetting and wicking and optionally to provide microbial growth inhibition where such coatings have improved coating properties and are, upon cure, less prone to cracking, flaking and particle generation.

Abstract: The present invention provides a heat exchanger having a coating with durability which causes neither adhesion of sludge nor separation of the coating within a short time. The surface of the heat exchanger is coated with a fluororesin having excellent chemical resistance and characteristics in that the hardness is R96 or more, the taper abrasion is less than 8.7 mg, the linear expansion coefficient is 7.5 to 8.0.times.10.sup.-5 /.degree.C., and the elongation is 223 to 280%. The fluororesin is preferably poly chloro tri fluoro ethylene with 1-2 weight percent cobalt.

Abstract: Interior surfaces of an air handler unit are coated with a dense, non-porous material, which discourages and prohibits growth of mold, spores, algae, bacteria, germs, viruses and other organisms and microorganisms and allergens. Air is drawn into the air handler unit through a return duct and one or more filters, through a heat exchanger and into a blower within the air handler unit. The blower draws and discharges air through highly reflective, interiorly coated chambers, where the air is bathed with direct and reflected ultraviolet light. The clean, conditioned air is then delivered through main distribution and supply ducts.

Abstract: A ceramic composite is provided comprising ceramic fibers and microparticles bound together as a porous matrix with a ceramic binder. The ceramic composite is particularly useful for transporting cryogenic fluids.

Abstract: Microextruded tubes each having two side surfaces, front and trailing edge surfaces and two ends are provided for insertion into aligned slots in headers to complete a heat exchanger assembly. The tubes each include a first coating composition containing an adhesive binder vehicle, flux material and brazing alloy deposited on the side surfaces adjacent the ends of the tube. The first coating composition is structurally arranged and applied to engage the aligned slots in the headers upon the insertion of the ends of the tubes into the header. The side surfaces of the microextruded tube include a second surface coating containing an adhesive binder vehicle, flux material, zinc and silicon extending the length of side tube between the deposited first coatings. The front and trailing edge surfaces of the tube include a third surface coating composition containing adhesive binder vehicle, flux material and zinc. A method of manufacturing parallel flow-type heat exchangers is disclosed.

Abstract: A hydrophilic coating for aluminum comprising a substantially chromium-free treatment including phosphoric acid, boric acid and optionally molybdic acid.

Abstract: A reactor arrangement and process for indirectly contacting a reactant stream with a heat exchange stream uses multiple passes of the heat exchange stream in a transverse flow arrangement to control temperature conditions over the width and length of channels through which the reactant passes. The heat transfer coefficient may be varied by changing the number and/or the arrangement of the corrugations along the plates or adding a heat adjustment plate to a channel containing the heat exchange fluid. The reactor arrangement and process of this invention may be used to operate a reactor under isothermal or other controlled temperature conditions. The variation in corrugation arrangements within a single heat exchange section is highly useful in maintaining a desired temperature profile in an arrangement having a cross-flow of heat exchange medium relative to reactants. The corrugations arrangement eliminates or minimizes the typical step-wise approach to isothermal conditions.

Abstract: An aluminum-containing metal composite material useful for heat exchangers having a satisfactory hydrophilic property, water-resistance and resistance to swelling with water and an enhanced durability is produced by coating an aluminum-containing metal substrate with an undercoat chemical conversion layer and then with an uppercoat resinous layer formed from a cross-linking reaction product of a polymeric compound (a) having a reactive amide, hydroxyl or carboxyl group with a cross-linking agent (b), in the presence of a water-soluble polymeric compound (c) having a sulfonic or sulfonate group, and in the cross-linking reaction product, the cross-linked molecules of the polymeric compound (a) form water-insoluble, three-dimensional network structures, and the molecules of the polymeric compound (c) are held in the network structures and thereby exhibit substantially no eluting property in water.

Abstract: A composition containing an antimicrobial and a silicone-based emulsion is disclosed for treating heat exchange surfaces. The liquid formulation retards microbial growth and prevents debris from adhering to the surfaces, thus minimizing fouling. The composition does not form a film on the treated surfaces, but rather clings via ionic interaction; thus the heat transfer characteristics of the system are not substantially altered. In addition, the composition does not contain any volatile organic compounds, which can be harmful to a building's occupants. An application method is further disclosed that entails spraying the composition into the cooling coils to be treated, drawing the composition across the heat exchange surfaces in an air stream, and drying the surfaces. This method results in the formation of a low-friction antimicrobial deposit that will resist fouling and microbial growth.

Abstract: A heat exchanger for use in applications with high temperatures and rapidly changing thermal gradients. The heat exchanger has a shell, a head, a tubesheet, a tubesheet skirt, and a tube bundle. The tubesheet has a peripheral diameter smaller than the inner diameter of the interior of the head and is coupled to the head by the tubesheet skirt. The gap between the tubesheet and the head is sufficient to allow the removal of the tubesheet from the head after the tubesheet suffers typical thermal deformation. In a preferred embodiment, the head defines a chamber having a combined spherical-cylindrical geometry.

Abstract: A heat exchanger wall for the transfer of heat from one first medium on one side of the wall to a second medium to be evaporated on the other side of the wall, with this other side having integral, aligned distributor grooves for distributing the liquid phase of the second medium. Good distribution of the liquid on the surface of the heat exchanger wall and simultaneous good vaporization characteristics are guaranteed according to the invention by the following characteristics:a) the distributor grooves cross channels having a pitch t, which channels lie below the distributor grooves,b) the distributor grooves are formed by laterally displaced material of the channel walls, with the depth T of the distributor grooves lying approximately between 30% and 90% of the channel height h, andc) the distributor grooves are connected to the channels through flared segments and/or openings in the distributor grooves.

Abstract: A stack type evaporator including tubular elements 1 each having a plurality of inwardly protruding recessed ribs 7 which extend from an upper header portion 1a of the element to a lower header portion 1b, with the ribs serving as straight drain canals 7a. A hydrophilic resin coating of a specific composition covers the outer surfaces of the tubular elements 1 and fins 2 each interposed between two adjacent tubular elements. The combination of straight drain canals with the specific hydrophilic resin coating is effective to facilitate the drainage of condensed water so that the waterdrops are perfectly prevented from flying out of the evaporator, and that any stinking mold or mildew is not permitted to grow within a reduced amount of remaining adherent water. Also, the hydrophilic coating itself does not emit any unpleasant smell which has been inevitable to the prior art water glass coating, thus an air-conditioned environment always remains comfortable.

Abstract: A nonabrasive, corrosion-resistant, hydrophilic coating on aluminum sheet such as fin stock, produced by applying to the sheet surface a coating material containing, in an aqueous vehicle, effective amounts of nitrilotrismethylenetriphosphonic acid, phosphoric acid, and borate material of the group consisting of zinc borate and sodium borate, and essentially free of silica, alumina and precursors thereof, and heating the surface to establish the coating thereon. The coating formulation may also contains up to about 1 wt. % of polyacrylic acid and a surfactant to aid in application.

Abstract: Water based silicone coating compositions are provided offer superior coating properties, durability and resistance to high temperatures and to the effects of corrosive environments. These coating compositions are especially useful for coating the external and intricate internal surfaces of high temperature aluminum heat exchangers.

Abstract: A stack type evaporator includes tubular elements 1 each having a plurality of inwardly protruding recessed ribs 7 which extend from an upper header portion 1a of the element to a lower header portion 1b, with the ribs serving as straight drainage canals 7a of specified width and area. A hydrophilic resin coating of a specific composition covers the outer surfaces of the tubular elements 1 and fins 2 each interposed between two adjacent tubular elements. The combination of straight drainage canals, the specified width and area thereof and the specific hydrophilic resin coating is effective to facilitate the drainage of condensed water so that the waterdrop is substantially prevented from flying out of the evaporator, and the hydrophilic coating itself does not emit any unpleasant smell.

Abstract: A heat transfer tube having an internal surface that enhances the heat transfer performance of the tube. Helical ribs project from the internal surface of the tube. The ribs have a pattern of parallel notches intersecting and impressed into them at a small angle of inclination with respect to the longitudinal axis. The pattern of ribs and notches increase the total internal surface area of the tube and also promote conditions for the flow of refrigerant within the tube that increase heat transfer performance. The tube is suitable for use in both refrigerant evaporators and condensers.

Abstract: A method of applying a surface hydrophilic treatment to a heat-transfer tube with a good productivity, which obtains an excellent surface hydrophilic property not deteriorated for a long term. The method includes the steps of: heating a copper or copper alloy heat-transfer tube for 5 to 10 min at a temperature ranging from 250.degree. to 350.degree. C. in an atmosphere mainly containing an inert gas; and applying corona discharge or plasma discharge to the copper or copper alloy heat-transfer tube. To prevent the coloring, the atmosphere preferably contains O.sub.2 in a concentration of 3% or less and CO in a concentration of 1 to 5%, the balance being an inert gas.

Abstract: A heat dissipating plate having rows of upright radiating rods and rows of V-shaped radiating fins alternatively aligned at the top of a flat base thereof, each two adjacent V-shaped radiating fins of the same row defining an air passage for letting heat be quickly carried away by air.

Abstract: An alternating-flow heat exchanger and method of forming is disclosed, in which a substrate is provided having open-ended, straight passageways therethrough, and at least one end cap for diverting flow in said passageways into primary and secondary flow paths. The ceramic substrate is coated with a desirable coating. The end cap is then applied to the substrate to direct flow from the passages in first and second flow paths.

Abstract: There is provided heat exchange tube formed from a ductile metal strip which is formed into a generally circular configuration with the opposing longitudinal edges of the strip welded together. Both surfaces of the strip are enhanced. On one surface, the enhancement constitutes parallel rows of vertical fins separated by channels. Conduits which run along the channels and are located at the base of one side of the fins facilitate bending of the fins about the fin base to form a nucleate boiling surface. On the opposing surface of the tube, the enhancement constitutes parallel rows of protrusions separated by a distance effective to generate turbulence in a fluid passing along the second surface. In a preferred embodiment, the protrusions are in the form of truncated cones.

Abstract: A black liquor process for paper pulping uses a nucleic boiling surface in a series of multi-effective evaporators. The nucleic boiling surface may be used to retube all effects or a single effect.