Abstract: An evaporator surface structure of a circulating fluidized bed boiler having a furnace that is enclosed by sidewalls and has a bottom and a ceiling. The evaporator surface structure includes at least one vertical and separate evaporator surface unit that is spaced apart from the sidewalls of the furnace. The at least one evaporator surface unit (i) is formed of planar water tube panels that extend from the bottom of the furnace to the ceiling of the furnace, and (ii) consists of two cross-wise joined vertical water tube panels.

Abstract: A method of fabricating boiler water walls that includes the steps of forming a subpanel formed of at least one fin and one tube by laser arc welding the at least one fin to the one tube and then laser arc welding a predetermined plurality of subpanels together in a two-dimensional plane by laser arc welding an additional joining element between respective subpanels to form the water wall.

Abstract: A water heater includes a water pipe form by bending a pipe. The entire water pipe leans related to a vertical plane to expose all the section to a burner thereunder. All the sections of the water pipe lean downwards related to a horizontal plane. It will make the water in the water in the water pipe flows backwards when no water is supplied to the water heater. Therefore, there will never be water remaining in the water pipe to get rid of the jam problem.

Abstract: A steam generation boiler having a reaction chamber formed by a bottom portion in a lower portion, a roof portion at an upper portion, and walls extending vertically between the bottom portion and the roof portion. The walls include vertical end walls having a tapering wall section that tapers symmetrically with respect to its middle axis towards the bottom portion, in which (i) a first group of steam pipes in the tapering wall section including steam pipes on both sides of the middle axis, pass at an angle with respect to the middle axis in a wall plane of the tapering wall section, and from the wall plane into the reaction chamber, and (ii) a second group of steam pipes arranged to pass to the bottom portion along the wall plane.

Abstract: A steam boiler includes a boiler housing. A helical coil for boiling water and superheating the wet steam is disposed within the boiler housing. A burner emits combustion gases which heat a heat emitter which is disposed in the inner space of the helical coil. Combustion gases from the burner enter the internal cavity of the heat emitter and then pass through perforations in the heat emitter before contacting the helical coil. As such, the heat emitter is heated by the combustion gases and serves as a radiant heat source for the helical coil.

Abstract: A continuous steam generator with a combustion chamber having a number of burners for fossil fuel and an outside wall composed of steam generator pipes that are welded to each other gas-tight is provided. A vertical gas flue is connected downstream of the combustion chamber on the hot gas side in an upper area via a horizontal gas flue, wherein a part of the outside wall facing the vertical gas flue and below the horizontal gas flue is inclined inward and thus forms a nose projecting into the combustion chamber with the bottom of the adjacent horizontal gas flue. Support pipes are connected downstream of at least one part of the steam generator pipes of the nose at the upper end thereof on the flow medium side, wherein the support pipes are guided substantially vertically to the lower end of the nose.

Abstract: A heat exchanger A1 includes: a case 2 surrounding a heat transfer tube 4; and a guide member 5 for guiding heating gas entering the case 2 through an intake vent 21 to a first space region 24A and then to a second space region 24B, the guide member 5, together with a wall portion 20b, defining therebetween a gap 25b in communication with a gap 25a between the wall portion 20b and the heat transfer tube 4 for allowing part of the heating gas having been guided to the first space region 24A to proceed into the second space region 24B through the gaps 25a and 25b. This arrangement performs efficient heat recovery from the heating gas by effectively utilizing the entire heat transfer tube 4 while alleviating a problem that the case 2 is partially heated to elevated temperatures.

Abstract: A furnace of a boiler for a power plant includes an outer water tube section adapted to receive water from the outside and heat the water into hot water (including steam); and an inner water tube section adapted to receive water from the outside and heat the water into hot water (including steam) while allowing the water to be moved upwardly. The outer water tube section is formed in a shape gradually increasing or substantially uniform in diameter from the bottom toward the middle portion M, and gradually decreasing, increasing and decreasing again in diameter from the middle portion M toward the top, and the inner water tube section is formed in a shape gradually decreasing and increasing in diameter from the bottom toward the middle portion M, and gradually decreasing, increasing and decreasing again in diameter from the middle portion M toward the top.

Abstract: A steam generator is provided. The steam generator has a combustion chamber having a peripheral wall formed at least partially from gas-proof, welded steam generator pipes, at least two additional inner walls formed at least partially from additional steam generator pipes which are arranged inside the combustion chamber. The inner walls are connected one behind the other on the flow medium side by an intermediate collector. The steam generator has a high service life and is reliable. The flow medium on the inlet of the inner wall upstream of the intermediate collector has a lower temperature than that of the flow medium on an inlet of the peripheral wall.

Abstract: A spiral heat exchanger for producing heating and/or sanitary use hot water, specifically designed for condensation applications, characterized in that said spiral heat exchanger comprises a duct, preferably though not exclusively made of a thermally conductive material and having a contoured cross-section, called outer duct, inside which can be either arranged or not a second duct, preferably though not exclusive made of a thermally conductive material, called inner duct; the geometrical construction of said outer duct being defined as a resultant obtained by joining two different diameter circumferences, said circumferences being spaced from one another by a constant or variable radius junction pattern; the thus obtained single or double duct being coiled or spiral wound on a diameter substantially larger than the size of said duct thereby providing a hollow cylinder.

Abstract: Bent-out wall in the region of a substantially rectangular burner opening (2), wherein the bent-out wall (1) is formed by tube walls (3) and the tube walls (3) consist of tube-fin-tube combinations welded in a gastight manner and the tubes (5) thereof are flowed through by a cooling medium, wherein at least part of the bent-out wall (1) along the two longitudinal sides (7) of the rectangular burner opening (2) is formed by means of prefabricated tube wall segments (4) and wherein the prefabricated tube wall segments (4) are machine-welded in the planar state at the workshop and are subsequently bent at the workshop to a wall bending radius (R) of 70-140 mm and a wall bending angle (W) of 110°-150°.

Abstract: A fluid heater constructed of rectangular tubing through which fluid to be heated is circulated in a circuitous path. The floor and walls of a combustion chamber of the heater are constructed of the rectangular tubing. A tubular coil stack is positioned over the combustion chamber and surrounded by coil stack chamber walls constructed of the rectangular tubing. Consequently, all surfaces of the fluid heater exposed directly to flame are constantly cooled by the fluid to be heated. A combustion unit of the fluid heater is removable to facilitate maintenance.

Abstract: A furnace tube arrangement for a steam generator is described. A plurality of furnace tubes disposed longitudinally form a generally planar wall structure into which burner throats are let at least two longitudinally spaced levels in familiar manner. Burner throats at the respective levels are so disposed that a vertical mid-line of each throat at a first level is laterally offset from a vertical mid line of a corresponding throat at a second level.

Abstract: Disclosed is a boiler for providing hot water to a heating system of a building and for simultaneously producing hot domestic water. This boiler comprises a heating tank provided with a water inlet and a water outlet through which water for use in the heating system circulates and an adjacent chamber annexed to the heating tank. This adjacent chamber is in direct communication with the heating tank and containing means for heating the water. The boiler also comprises a heat exchanger provided with a water inlet and a water outlet through which circulates the domestic water. This heat exchanger is made of a plurality of tubular coils of helicoidal shape that are located within the heating tank in order to allow heat transfer between the hot water within the heating tank and the domestic water that circulates within the tubular coils.

Abstract: A water tube WT of a heat exchanger B includes a helical tube body 5 which includes a plurality of loops 50 arranged in the axial direction. At least one of the loops 50 includes an inclined tube portion which is inclined with respect to the axial direction and a non-inclined tube portion extending perpendicularly to the axial direction. The inclined tube portion is provided at each of opposite end regions s2a and s2b in a width direction crossing the axial direction, whereas the non-inclined tube portion is provided at an intermediate region S1 in the width direction. With this structure, the pitch p2 of the loops 50 is reduced. Therefore, by increasing the number of loops 50, high heat exchange efficiency is achieved without considerably increasing the size of the helical tube body 5.

Abstract: A steam generation boiler includes a bottom portion and a roof portion, as well as walls that extend vertically between the bottom portion and the roof portion, thus forming a reaction chamber of the steam generation boiler, the walls of which reaction chamber embody a structure that includes steam generator pipes. The steam generation boiler includes, in its lower portion, at least one wall section tapering towards the bottom portion. A first group of steam pipes in the tapering wall section is arranged to pass from the wall plane into the reaction chamber and to extend from the wall plane to the bottom portion of the steam generation boiler on the side of the reaction chamber forming a wall in the reaction chamber, and a second group of steam pipes is arranged to pass to the bottom portion along the wall plane.

Abstract: A boiler furnace avoids NOx and increases thermal efficiency with a small boiler. The boiler furnace has a outer water walls and inner water walls. All of the water walls contain water which absorb heat from the flame and cool the water tube which act as a container, passage, evaporator of water and water walls with membrane that connect water tubes to each other. The spaces between outer water walls and inner water walls makes a cylindrical space which contain fires and avoids making a fire that produces nitrogen oxides due to high temperature induced from a concentrated flame.

Abstract: A steam boiler, comprising a boiler body accommodating water and steam therein and a burner throwing flames toward a central through-hole of the boiler body and water pipes formed to cross the inside of the central through-hole of the boiler body, and directly heated by the flames of the burner and an internal cylinder formed to cover the outside of the boiler body so as to form a space between the internal cylinder and the outer wall surface of the boiler body where burned discharge gas flows from the lower side to the upper side and an external cylinder formed to cover the outside of the internal cylinder so as to form a space between the external cylinder and the outer wall surface of the internal cylinder where air for combustion flow such that heat exchange between the air for combustion and the discharge gas is performed.

Abstract: A combustion apparatus includes a cylindrical combustion chamber surrounded by an inner wall. A cooling chamber comprises an intermediate wall spaced from the inner wall. Cooling water flows in and out lower and upper sides of the intermediate wall, to cool the inner wall by the cooling water that flows into a space formed between the inner and intermediate walls of the cooling chamber. A lateral combustion air supply chamber comprises an outer wall spaced from an outer side of the intermediate wall. Combustion air is supplied at an upper side of the outer wall to thereby make the air in a tangential direction with respect to the cylindrical outer wall turn and fall in a space formed between the intermediate wall and the outer wall, so that the combustion air is supplied to the combustion chamber via an opened lower portion of the lateral combustion air supply chamber.

Abstract: Apparatuses and methods for producing steam are provided. A steam boiler system may include a steam boiler. The steam boiler may comprise an enclosure with a burner, first and second fluid conveyance members, and one or more radiants therein. The burner produces hot combustion gases which warm the fluid conveyance members and thereby the fluid therein. The radiants are also heated by the combustion gases, and they thereby emit radiation which is absorbed by the fluid conveyance members and/or the fluid therein. The boiler system may additionally comprise a steam separator which separates out a steam component. The steam component can be directed back through the enclosure in a third fluid conveyance member to expand the steam before being fed to a steam engine to produce power.

Abstract: Disclosed herein is a once-through boiler capable of achieving a steep increase in temperature of steam via reheating of the steam within a combustion chamber, thereby improving heat and energy efficiency. The boiler comprises a body (110), a steam supply unit (120), and a heating unit (130). The body includes a housing (111), a cover (112), and a guide pipe (113). The steam supply unit includes an annular water tank (122) in a lower region of the body, a steam supply chamber (124) in an uppermost region of the body, water pipes (121) amounted on the water tank, a low-temperature steam inlet pipe (125) and a high-temperature steam outlet pipe (127) mounted at opposite sides of the water pipes, and a steam heating pipe (126) to communicate the inlet pipe with the outlet pipe. The heating unit includes a burner (131), and a combustion chamber (132).

Abstract: A high-efficiency hot-water boiler for a heating system of a building is provided. The boiler includes a boiler enclosure that contains a furnace area compartment within an insulated sealed casing, a first watertube compartment within a sealed casing, a second watertube compartment within a sealed casing, and an air-to-air preheat exchanger within a sealed casing. A plurality of separate, closely-spaced watertubes extends within each of the compartments and provides paths for working fluid to flow through the compartments for purposes of transferring heat to the working fluid. A burner is located within the furnace area compartment for combusting an air/gas mixture.

Abstract: An integral pressurized water nuclear reactor for the production of steam utilizing a helical coil steam generator, a plurality of internal circulation pumps, and an internal control rod drive mechanism structure.

Abstract: A fluid heater constructed of rectangular tubing through which fluid to be heated is circulated in a circuitous path. The floor and walls of a combustion chamber of the heater are constructed of the rectangular tubing. A tubular coil stack is positioned over the combustion chamber and surrounded by coil stack chamber walls constructed of the rectangular tubing. Consequently, all surfaces of the fluid heater exposed directly to flame are constantly cooled by the fluid to be heated. A combustion unit of the fluid heater is removable to facilitate maintenance.

Abstract: A heat transfer system having a a radiant source, a first heat exchanger configured to permit a first fluid to flow therethrough, and a thermal shield configured to provide controlled radiative heat from the radiant source to the first exchanger. The radiant source is a flame. The thermal shield is a second heat exchanger configured to permit a second fluid to flow therethrough or a non-contact thermal shield fabricated from a material arranged to provide controlled radiative heat exposure from the radiant source to the first exchanger. Oxy/coal combustion systems are also disclosed.

Abstract: A furnace of a boiler for a power plant includes an outer water tube section adapted to receive water from the outside and heat the water into hot water (including steam); and an inner water tube section adapted to receive water from the outside and heat the water into hot water (including steam) while allowing the water to be moved upwardly. The outer water tube section is formed in a shape gradually increasing or substantially uniform in diameter from the bottom toward the middle portion M, and gradually decreasing, increasing and decreasing again in diameter from the middle portion M toward the top, and the inner water tube section is formed in a shape gradually decreasing and increasing in diameter from the bottom toward the middle portion M, and gradually decreasing, increasing and decreasing again in diameter from the middle portion M toward the top.

Abstract: An economizer for a heat recovery steam generator utilized to improve the efficiency of the Rankine cycle by preheating the water that flows to the evaporator section. The economizer multi-pass sections include up-flow tubes only. This arrangement greatly reduces thermal stresses on the tubes by ensuring that each individual tube in any fluid-flow pass operates at the same or similar temperature. The design of the invention does this by causing all tubes in any fluid-flow pass to have the same upwards fluid flow direction and similar fluid flow velocity. No unstable backflow (i.e. flow in the reverse direction) occurs in any of the tubes. Heated down-flow tube sections are totally eliminated in this design. Respective jumper pipes are provided to conduct the water from the top of an economizer panel to the bottom of an adjacent panel.

Abstract: In a steam generator, a flow resistance adjusting unit for a primary cooling water is provided in an inlet nozzle provided at an incoming water chamber or an outlet nozzle provided at an outgoing water chamber.

Abstract: A boiler furnace avoids NOx and increases thermal efficiency with a small boiler. The boiler furnace has an outer water wall and an inner water wall with flared top and bottom portions.

Abstract: The present invention relates to a heating, sterilizing and drying appliance using a superheated steam generator, comprising: a saturated steam distributor 10 adapted to selectively distribute saturated steam which is produced by a boiler 11 and then is separated from condensed water while passing through a separator 12 in the process of opening a valve assembly 13; a superheated steam generator 20 adapted to allow streams of the steam supplied thereto from the saturated steam distributor to generate vortices while passing through a plurality of disc-like interval-maintaining means 23 stackingly arranged on top of one another longitudinally in a combustion chamber 21 thereof and adapted to heat the vortex-generating steam through a plurality of superheated steam heating means 22 penetratingly mounted vertically in the plurality of interval-maintaining means to thereby produce superheated steam; and a superheated steam supply line 30 adapted to inject the superheated steam which is produced by the superheated

Abstract: The present invention relates to an instantaneous steam boiler generating steam in a steam cleaner, a steam-vacuum cleaner, a steam iron, etc. The instantaneous steam boiler has a substantially short traveling path of water against the formation of fur by insertedly molding a separate flow tube while being in contact with a U-shaped heater.

Abstract: A gravity feed, natural circulation boiler for an SAGD process using low quality feedwater for carbonatious material recovery, has a large diameter steam drum with downcomers. A furnace of the boiler has individually replaceable membrane wall modules, each with upper and lower headers and membrane roof, wall and floor parts connected to the drum and defining a fire box having an inlet end and an outlet end. The furnace includes a membrane front wall connected to the drum with a windbox upstream of the front wall. Burners at the inlet end of the firebox heat the firebox and riser pipes are connected between the steam drum and the upper header for supplying steam to the steam drum when the firebox in heated, the downcomer pipes being connected to the lower header for supplying water from the stream drum under gravity feed so that each module defines a single circuit.

Abstract: The invention relates to a pipe assembly (102) for use in a boiler. The pipe assembly (102) comprises a pipe (104) having an outer wall (106) adapted for heat exchange. The pipe (104) having heat sensing means (116) located in a recess section of the outer wall (106) thereof, wherein an internal bore (108) of the pipe (104) has a substantially constant cross section in the region of the heat sensing means (116).

Abstract: Disclosed is a steam generator pipe which can be produced in a simple and economical manner and which has a particularly good heat transitional behavior having a large band width with various operational conditions. According to the invention, at least one insert is arranged in the inner chamber of the pipe in order to form a swirl-generating inner profile. The insert comprises a plurality of wires which wind, in a screw-like manner, along the inner wall of the pipe in the form of a multi-path thread.

Abstract: A water tube WT of a heat exchanger B includes a helical tube body 5 which includes a plurality of loops 50 arranged in the axial direction. At least one of the loops 50 includes an inclined tube portion which is inclined with respect to the axial direction and a non-inclined tube portion extending perpendicularly to the axial direction. The inclined tube portion is provided at each of opposite end regions s2a and s2b in a width direction crossing the axial direction, whereas the non-inclined tube portion is provided at an intermediate region S1 in the width direction. With this structure, the pitch p2 of the loops 50 is reduced. Therefore, by increasing the number of loops 50, high heat exchange efficiency is achieved without considerably increasing the size of the helical tube body 5.

Abstract: Provided is a boiler including: a plurality of heat transfer tubes arranged to form a cylindrical shape between an upper header and a lower header to constitute a heat transfer tube row; and a plurality of longitudinal fins provided to close gaps between the heat transfer tubes without connecting the adjacent heat transfer tubes, the plurality of longitudinal fins being provided to a portion other than one of one end in a vertical direction of the heat transfer tube row and a part in a peripheral direction thereof.

Abstract: The present invention relates to an instantaneous steam boiler generating steam in a steam cleaner, a steam-vacuum cleaner, a steam iron, etc. The instantaneous steam boiler includes a U-shaped heater and a separate flow tube arranged in parallel and contact with said heater. The flow tube may be arranged orthogonally or at a 180 degree opposite direction and may include a circular or square-shaped end with rounded edges, thereby increasing the heating/vaporization efficiency of the device.

Abstract: A boiler is described comprising a housing with a flue gas inlet for receiving a hot gas flame and an outlet for venting a hot gas produced by the hot gas flame, and a tube assembly mounted within the housing. The tube assembly comprises a lower manifold for receiving a liquid, an upper manifold for receiving a heated version of the liquid; and, a plurality of tubes disposed between the lower and upper manifolds. Each tube is shaped to provide a hot gas pathway that travels in a parallel fashion along at least a lower portion of the longitudinal extent of each tube in the tube assembly to the outlet, whereby the liquid introduced into the lower manifold travels in the plurality of tubes and receives heat from the hot gas along the extent of the hot gas pathway.

Abstract: A steam generator has a continuous heating surface located in a fuel gas channel that can be traversed in an approximately horizontal fuel gas directions. The continuous heating surface has a plurality of steam generator pipes that are connected in parallel for the passage of a flow medium and is designed in such a way that a steam generator pipe, which is heated to a greater extent than another steam generator pipe of the same continuous heating surface, has a higher throughput of the flow medium than the other steam generator pipe. The aim is to produce a low-cost steam generator with a particularly high level of mechanical stability, even when subjected to different thermal stresses.

Abstract: A boiler (10) in which a liquid medium is heated and steam is generated. The boiler (10) includes a housing (12), and a burner (25) for generating hot combustion gases within the housing (12). The boiler also includes a lower drum (30) for receiving the liquid medium, and an upper drum (36) for receiving steam which is generated. A plurality of first tube banks (44) are disposed on both sides of the upper drum (36). The first tube banks (44) including a plurality of first fluid tubes (42) for establishing fluid communications between the lower and upper drums (30, 36), with each first fluid tube defining at least one inwardly extending portion (52). Also provided are a plurality of second tube banks (46) disposed on both sides of the upper drum (36), with the second tube banks (46) being disposed substantially opposite the first tube bank (44).

Abstract: A support plate for retaining tube array spacing within a heat exchanger tube and shell structure. The support plate having a plurality of individual tube receiving aperture formed therein. Each apertures has at least three inwardly protruding members and bights are formed therebetween when the tube associated therewith is lodged in place to establish secondary fluid flow through the support plate. The inwardly protruding members terminate in flat lands that restrain but do not all contact the outer surface of the respective tube. These flat lands minimize fretting wear and eliminate potential gouging of the outer wall of the tube. The plate wall forming each aperture has an hourglass configuration which, inter alia, reduces pressure drop, turbulence and local deposition of magnetite and other particulates on the support plates.

Abstract: A convection pass enclosure for a boiler comprising a front wall having a gas inlet for receiving gases from the boiler; right and left side walls connected to the front wall; a rear wall having a gas outlet, the rear wall being connected between the right and left side walls; and a roof, at least one of the front wall, right side wall, left side wall and rear side wall having a heat exchanger surface in the form of a horizontal spiral tube assembly.

Abstract: A vaporizer includes a pump for pumping liquid stored in a liquid store tank, a helical vaporizing tube, and a control system connected to two ends of the vaporizing tube for functioning to make the vaporizing tube produce high temperature so as to heat up swiftly liquid flowing through the helical vaporizing tube and finally vaporize liquid at the outlet end of the vaporizing tube, with the liquid in the helical vaporizing tube never reversely flowing back to the pump owing to low temperature of liquid at the inlet end of the helical vaporizing tube.

Abstract: A steam generator system incorporates multiple processes, either in series or independently and with each process having a process fluid associated therewith, to transfer heat between a common working fluid and the process fluids in order to generate steam from the working fluid. The heat transfer may be controlled by controlling the flow of the working fluid to further regulate and control the generation of steam and/or the individual processes themselves. The generator system includes a vessel and may optionally have baffles located within the vessel to separate the flow of working fluid into a recirculation system to facilitate in the overall operation of the system. The working fluid must be capable of forming steam and preferably consists essentially of water. Straight tubes, plate-type heat exchange surfaces having a common boiling fluid stream, U-tubes, helical tubes, and/or curved tubes may be used as heat exchange means for transferring heat between the working fluid and the process fluids.

Abstract: A gas-fired humidifier includes a heat exchanger with a plurality of generally upwardly extending tubes. These are connected at their lower ends to a source of water and at their upper ends to a steam header. A gas-fired burner is arranged to direct heat to the exterior of the tubes so as to cause water therein to boil and form steam in the steam header.

Abstract: A steam generator system incorporates multiple processes, either in series or independently and with each process having a process fluid associated therewith, to transfer heat between a common working fluid and the process fluids in order to generate steam from the working fluid. The heat transfer may be controlled by controlling the flow of the working fluid to further regulate and control the generation of steam and/or the individual processes themselves. The generator system includes a vessel and may optionally have baffles located within the vessel to separate the flow of working fluid into a recirculation system to facilitate in the overall operation of the system. The working fluid must be capable of forming steam and preferably consists essentially of water. Straight tubes, plate-type heat exchange surfaces having a common boiling fluid stream, U-tubes, helical tubes, and/or curved tubes may be used as heat exchange means for transferring heat between the working fluid and the process fluids.

Abstract: The invention provides a water-tube boiler which allows further NOx reduction and CO reduction with a simple construction of the boiler body and the burner itself. The water-tube boiler includes a first water tube array made up of a plurality of first water tubes arranged into an annular shape, a combustion chamber defined inside the first water tube array, a first opening defined at part of the first water tube array, a cooling water tube array made up of a plurality of cooling water tubes arranged into an annular shape in a zone within the combustion chamber where burning-reaction ongoing gas is present, gaps provided between adjacent cooling water tubes so as to permit the burning-reaction ongoing gas to flow through, and a burning-reaction continuing zone, where burning reaction is continuously effected, provided between the cooling water tube array and the first water tube array, whereby the burning-reaction ongoing gas generally uniformly contacts the individual cooling water tubes.

Abstract: A water-tube boiler which allows further NOx reduction and CO reduction to be implemented with an uncomplicated construction of the boiler body itself, and which is improved in boiler efficiency. The water-tube boiler includes a first water tube array made up of a plurality of first water tubes arranged into an annular shape and a combustion chamber inside the first water tube array.

Abstract: Refinery process furnaces are disclosed that have horizontal-helical radiant coils and/or improved ladder-type supports for the horizontal tubes. The coils have a tubeside fluid flow path from an inlet pipe section through an alternating series of straight horizontal pipe sections and wide sweep return bends to an outlet pipe section. The horizontal pipe sections are arranged in at least two vertical banks that are parallel and horizontally spaced apart. The bent pipe sweep return bends are arranged in vertical banks at either end of the straight pipe banks. Each bend connects a pair of straight pipe sections in adjacent vertical banks, and each return bend is sloped between horizontal and vertical so that one of the straight pipe sections in the connected pair thereof is elevated with respect to the other. The ladder supports have two opposing columns with a number of vertically spaced support members each having a generally horizontal upper engagement surface.