Abstract: A shell-and-plate heat exchanger includes: a shell forming an internal space; and a plate stack, disposed in the internal space, including heat transfer plates that are stacked and joined together. The shell-and-plate heat exchanger is configured to allow a refrigerant that has flowed into the internal space to evaporate. The plate stack forms: refrigerant channels that communicate with the internal space and through which a refrigerant flows; and heating medium channels that are blocked from the internal space and through which a heating medium flows. Each of the refrigerant channels is adjacent to an associated one of the heating medium channels with one of the heat transfer plates interposed therebetween. The shell-and-plate heat exchanger further includes one or more supply structures that supply the refrigerant to the refrigerant channels such that the refrigerant flows downward.

Abstract: A separator and distributor assembly for a falling film evaporator housed within the evaporator shell includes a housing defining a separation volume, a refrigerant inlet configured to admit a liquid and vapor refrigerant flow into the separation volume and one or more refrigerant gutters extending along a lengthwise axis of the housing. The refrigerant gutter has a gutter inlet at a bottom of the separation volume, and the one or more refrigerant gutters are configured to receive separated liquid refrigerant from the separation volume. One or more sparge channels are in fluid communication with the refrigerant gutters. The sparge channel includes one or more sparge openings at a top of the sparge channel vertically below the gutter inlet. The one or more sparge openings are configured to flow liquid refrigerant therefrom.

Abstract: A suction duct is disposed within a shell and tube heat exchanger. The suction duct is located relatively high and above the tube bundle so as to not entrain liquid or droplets that may be splashing and spraying upward. The suction duct is configured with an area schedule in fluid communication with a flow path inside the suction duct. The flow path is in fluid communication with an outlet of the shell. This is advantageous relative to traditional top of the shell outlets which generally have higher vertical footprints. The area schedule of the suction duct can facilitate and/or maintain relatively smooth vapor flow within the shell. The area schedule can achieve vapor flows that have some uniformity along the length of the shell, which can manage and/or avoid localized vapor flow and/or local currents, such as where high velocity may be present and where entrainment can result.

Abstract: A heat exchanger includes multiple aluminum heat transfer tubes through which a heat medium flows, and multiple aluminum connection pipes brazed to end portions of the heat transfer tubes. A heat equalizing member formed of a heat conductor is disposed to be in contact with at least two of the connection pipes and be capable of transferring heat therebetween. A method for producing the heat exchanger includes brazing the heat transfer tubes to the connection pipes in a state where the heat equalizing member is in contact with the at least two of the connection pipes.

Abstract: A falling film evaporator includes a plurality of evaporator tubes through which a volume of thermal energy transfer medium is flowed and a separator to separate a flow of liquid refrigerant from a vapor and liquid refrigerant mixture. A distributor distributes a flow of liquid refrigerant over the plurality of evaporator tubes. One or more vents stacks direct a flow of vapor refrigerant from the separator to a vent stack outlet in proximity to a refrigerant pool of the evaporator.

Abstract: A storage tank includes a condenser, a tank body having a storage space for storing a liquid phase working fluid, and a condenser core disposed in an interior of the tank body, wherein the tank body includes an upper body and a lower body, wherein a support plate is horizontally arranged within the upper body, wherein the condenser core includes a plurality of core elements, wherein each of the plurality of core elements includes upper end coupled to the upper body, lower end coupled to the support plate, and rear end coupled to a support member, wherein the support member extends to cross the upper body in a widthwise direction of the upper body.

Abstract: Heat exchange devices, including aseptic cooler devices, and systems including same are provided. Methods of using heat exchange device are also provided. In a general embodiment, the present disclosure provides heat exchangers having an open chamber configuration and including a first section containing a cooling or heating media and a second section containing a food product. The first section includes a level detecting device that is configured to maintain a level of cooling or heating media in the first section, while preventing the cooling or heating media from pressurizing the first section. The open chamber configuration provides an air break at a top portion of the first section that ensures that the cooling or heating media entering the first section is at, or close to, atmospheric pressure.

Abstract: A heat sink (100) for an electronic device comprising a first plate (102), a second plate (104) and a pipe (106). One side of the first plate (102) is in thermal contact with the electronic device. The second plate (104) is in thermal contact with the other side of the first plate (102). Further, the second plate (104) includes a hole and placed such that, a gap for airflow maintained between the first plate (102) and the second plate (104). One end the pipe (106) thermally coupled to the second plate (104). Thus facilitating the air flowing into the pipe (106) through the other end escapes the heat sink through the gap maintained between the first plate (102) and the second plate (104) via the hole on the second plate (104).

Abstract: A falling film evaporator for a heating ventilation and air conditioning (HVAC) system includes an evaporator housing and a plurality of evaporator tubes located in the evaporator housing and arranged into one or more tube bundles. A volume of thermal energy transfer medium is flowed through the plurality of evaporator tubes. One or more support sheets located along a length of the plurality of evaporator tubes to position and support the plurality of evaporator tubes in the housing, the one or more support sheets including one or more vapor flow passages to allow flow of vapor refrigerant along a length of the evaporator.

Abstract: The present invention relates to a method of producing multiple channels for use in a device for exchange of solutes between at least two fluid flows. The invention further relates to such a device. At least a first and a second sheet are comprised. The method comprises the steps of providing at least one of the first and second sheets with at least one profiled surface and joining the first and second sheets together with the profiled surfaces facing against each other. Channels are formed by the shape of the profiled surfaces.

Abstract: A heat exchanger includes a shell, a refrigerant distribution assembly and a heat transferring unit. The refrigerant distribution assembly includes a first tray part and second tray parts. The first tray part continuously extends generally parallel to the longitudinal center axis of the shell to receive a refrigerant that enters the shell. The second tray parts are disposed below the first tray part to receive the refrigerant discharged from first discharge apertures such that the refrigerant accumulated in the second tray parts does not communicate between the second tray parts. The second tray parts are aligned along a direction generally parallel to the longitudinal center axis of the shell. The heat transferring unit is disposed below the second tray parts so that the refrigerant discharged from second discharge apertures of the second tray parts is supplied to the heat transferring unit.

Abstract: An evaporator and a turbo chiller including the evaporator are provided. The evaporator may be a falling film evaporator which may distribute refrigerant to a heat pipe uniformly and which may also control two-phase flow by lowering dynamic pressures of gas refrigerant and liquid refrigerant, and separate the liquid refrigerant and the gas refrigerant from each other to enhance heat exchange efficiency.

Abstract: A vehicle includes axle housing, a differential and a ring gear, a scraper port, and a reservoir. The housing has a cover forming a heat exchanger having a coolant side and a lubricant side. The differential and ring gear are configured to pump a lubricating fluid. The scraper port is disposed at a bottom of the heat exchanger adjacent to the ring gear and is configured to direct the lubricating fluid through the lubricant side of the heat exchanger. The reservoir is disposed at a top of the heat exchanger and is configured to receive and store the lubricating fluid from the lubricant side of the heat exchanger.

Abstract: The present disclosure is directed to heat exchangers with flow distribution manifolds divided into an inlet section and a distribution section by a distributor. The inlet section may have a relatively small cross-sectional area that promotes mixed phase flow of liquid and vapor refrigerant. The manifolds may be used with multichannel tubes with flow path inlet sections that allow refrigerant to enter the flow paths through an outer wall of the tubes. In certain embodiments, a portion of the outer wall is removed to expose the flow paths to a distribution chamber within the inlet manifold. The multichannel tubes extend into the distribution section to partition the distribution section into a series of distribution chambers defined by a pair of adjacent tubes, the distributor, and the inlet manifold. Within each distribution chamber, the refrigerant may be directed into the multichannel tubes through the inlet sections of the multichannel tubes.

Abstract: A compact evaporator including a suction baffle system is provided for use in a refrigeration system. The suction baffle system includes a suction baffle and a passageway. The suction baffle includes a plurality of walls and is adjacent to the interior wall of shell. The passageway extends below one of the walls of the suction baffle toward the lower portion of the shell and is adjacent to the interior wall of the shell. A suction tube having an inlet is attached to the evaporator shell and the inlet is adjacent to the passageway and located partially below the suction baffle. The passageway minimizes the possibility of liquid carry-over in the suction tube that feeds into the compressor.

Abstract: This invention relates to an internal jet impingement type shell and tube heat exchanger in which the jet cooling tubes and the heating tubes in shell and tube heat exchanger are formed either as a staggered tube bundle or as a square tube bundle, and the orifices on each jet cooling tube are provided according to the arrangement of tube bundle. Thus, the heat transfer performance of jet impingement type shell and tube heat exchanger is remarkably enhanced.

Abstract: This invention relates to an internal jet impingement type shell and tube heat exchanger in which the jet cooling tubes and the heating tubes in shell and tube heat exchanger are formed either as a staggered tube bundle or as a square tube bundle, and the orifices on each jet cooling tube are provided according to the arrangement of tube bundle. Thus, the heat transfer performance of jet impingement type shell and tube heat exchanger is remarkably enhanced.

Abstract: Cooling performance of a cooler for pre-cooling humid gas supplied to a gas turbine power generation plant, etc. is improved by increasing heat transfer efficiency between the humid gas and cooling liquid flowing in heat exchanger tubes with utilization of condensed liquid generated due to the cooling of the humid gas. In a heat exchanger for cooling humid gas a flowing surrounding heat exchanger tubes 8 of the tube groups 9a and 9b by flowing cooling liquid r in the tubes, the liquid droplets cl generated by condensation of moisture contained in the humid gas are gathered and sprinkled or fallen in drops on a part of the heat exchanger tube group 9b, which results in increased heat exchange efficiency.

Abstract: The present invention provides a method and apparatus for using light emitting diodes for curing and various solid state lighting applications. The method includes a novel method for cooling the light emitting diodes and mounting the same on heat pipe in a manner which delivers ultra high power in UV, visible and IR regions. Furthermore, the unique LED packaging technology of the present invention utilizes heat pipes that perform very efficiently in very compact space. Much more closely spaced LEDs operating at higher power levels and brightness are possible because the thermal energy is transported in an axial direction down the heat pipe and away from the light-emitting direction rather than a radial direction in nearly the same plane as the “p-n” junction.

Abstract: A heat exchanger including a housing having a base and defining an interior. A plurality of coils are located in the interior of the housing and are arranged to extend upwardly from the base to define a coil depth. A blower is adapted to move air through the plurality of coils in a direction of the coil depth. A water distribution system is preferably located around a circumferential periphery of the plurality of coils to spray water on an outer surface of the plurality of coils along substantially the entire coil depth thereof. At least one air inlet opening is located in the housing to allow airflow across the plurality of coils. Additional embodiments of improved heat exchangers are disclosed herein.

Abstract: Ribbed heat exchange tubes in which the aspect ratio of the ribs is less than 5, provide greater indirect heat exchange than conventional heat exchange tubes with or without fins, when used in a slurry comprising a liquid phase, in which is dispersed flowing gas bubbles or particulate solids and flowing gas bubbles. The ribs, and typically also the longitudinal axis of the heat exchange tubes, are aligned in a direction parallel to, or spirally along the gas bubble flow direction. This is useful to increase either (i) the productivity of a slurry Fischer-Tropsch hydrocarbon synthesis reactor without an increase in the temperature in the reactor or (ii) increasing the production of higher molecular weight hydrocarbons by reducing the reaction temperature at a given feed conversion.

Abstract: In a driven axle assembly (12) for a motor vehicle that includes a differential housing located substantially in the center of the axle and tubes (16, 17) extending laterally from the differential, surrounding axle shafts (20) and opening into a lubricant reservoir (60) in the differential housing, a system for circulating and cooling axle lubricant includes a cover (26) for closing and sealing the housing having a first aperture into the housing where a ring gear rotates through the lubricant reservoir. The aperture in the cover opens to a chamber that holds lubricant carried through the aperture by the rotating ring gear. Conduit (72) connected by a hydraulic fitting to the chamber has its opposite end connected to an oil cooler mounted on the axle tube. Conduit (78) returns the lubricant to the reservoir in the differential housing.

Abstract: An evaporative heat exchanger of a medium condenser of a air/conditioning system with less cooling fins or even without cooling fins. The evaporative heat exchanger is composed of a plurality of streamline cross sectional tubes used instead of conventional round tubes for providing an evaporative efficiency, and being easy to clean and maintain.

Abstract: An evaporative heat exchanger of a medium condenser of a air condition system with less cooling fins even without cooling fins which a novel coil assembly composed of a plurality of streamline cross sectional tubes is used to instead of conventional round tubes for providing an ultra high evaporative efficiency therefore, and having the further improvement of easy to clean and convenient for maintenance.

Abstract: An apparatus for use in a counter flow heat exchange assembly that provides increased heat exchange. The apparatus includes a plurality of adjacently spaced arrays, each array having a plurality of cooling conduits that are connected to one another through the utilization of connector portions. The adjacent vertical arrays have a centerline-to-centerline distance extending between them that is greater than the diameter of each of the conduits employed. In addition, the apparatus includes a vertical partition that extends between some or all conduits of each array.

Abstract: A heater exchanger used to condense a refrigerant in a refrigeration system. The heat exchanger is designed to perform a heat exchanging operation by the use of latent heat of water vaporization, thus having improved heat exchanging efficiency as well as a reduced size.

Abstract: A method of exchanging heat is disclosed. Process fluid is passed through a dry indirect contact heat exchange section while a main air stream is also passed through that section. The process fluid is passed through a second indirect contact heat exchange section while a second air stream is passed through that section. A third air stream is passed through a direct contact heat exchange section and mixed with the second air stream to define the main air stream. Evaporative liquid is selectively distributed over the second indirect contact heat exchange section and over the direct heat exchange section. The distribution of evaporative liquid over one section is independent of the distribution of evaporative liquid over the other section.

Abstract: A method of exchanging heat is disclosed. Process fluid is passed through a dry indirect contact heat exchange section while a main air stream is also passed through that section. The process fluid is passed through a second indirect contact heat exchange section while a second air stream is passed through that section. A third air stream is passed through a direct contact heat exchange section and mixed with the second air stream to define the main air stream. Evaporative liquid is selectively distributed over the second indirect contact heat exchange section and over the direct heat exchange section. The distribution of evaporative liquid over one section is independent of the distribution of evaporative liquid over the other section.

Abstract: A system and method of exchanging heat are disclosed. Three heat exchange sections are used: a dry indirect contact heat exchange section, a second indirect contact heat exchange section that is operable in either a wet or dry mode, and a direct contact heat exchange section. The three sections are next to each other in an apparatus to reduce the overall height of the apparatus. The dry and second indirect contact heat exchange sections receive a process fluid in series or in parallel. Separate ambient air streams pass through the second indirect and direct contact heat exchange sections before mixing and entering the dry indirect contact heat exchange section. Another ambient air stream is mixed in upstream of the dry indirect contact heat exchange section when the system is operated in the dry mode. Two independent evaporative liquid distribution systems are included. One selectively distributes evaporative liquid over the second indirect contact heat exchange section.

Abstract: A system and methods of extracting heat are disclosed. The system may be arranged as a fluid cooler or as a fluid condenser. Three heat exchange sections are provided: a dry indirect contact heat exchange section; a second indirect contact heat exchange section that is operable in either a wet or dry mode; and a direct contact heat exchange section. As a fluid cooler, a connecting flow path connects the dry indirect contact heat exchange section to the second indirect contact heat exchange section. A bypass flow path extends from the dry indirect contact heat exchange section to the process fluid outlet.

Abstract: A compound condensing device to be used in an air conditioner having at least two condensing stages, one behind another, along the blowing direction of a common air blower to reduce the temperature and pressure of the refrigerant in the coiled pipe extending from the exiting end of the compressor and input end of the expanding device. In both condensing stages, coiled pipe sections are arranged in an up-and-down array, and evaporative cooling liquid droplets are distributed over the coiled pipe to extract heat from the refrigerant in the coiled pipe. Furthermore, fins and water-retaining material wrapping around the coiled pipe are used to increase the efficiency of evaporation. With the arrangement of two or more condensing stages, the exiting air from the compound condensing device has a temperature of about 28.5.degree. C.

Abstract: A multistage condensing structure using a liquid dispensing means to transfer droplets of evaporative cooling liquid onto an air-cooled condenser, taking advantage of the conventional air-cooled condensing method and the evaporation method using a liquid coolant. To further increase the efficiency of the air conditioner, two or more condensing units can be arranged in tandem along the blowing direction of a common air blower. With two or more condensing units arranged in tandem, the contacting area between the evaporation surfaces and the air flow can be enlarged to increase the evaporation efficiency without significantly increasing the size of the air conditioner. The multistage condensing structure, with its continuous heat-exchange along the flow of the refrigerant in the coiled pipe, causes an increase in the subcooling condition in the refrigerant. This condensing structure can, therefore, achieve a much higher E.E.R. than the known method of air cooling.

Abstract: A vapor compression refrigeration system for cooling a liquid in which there is a spray dispenser for distributing liquid refrigerant over the tubes in a shell-and-tube type evaporator. The differential pressure in the refrigerant flow loop across the evaporator is the sole means of producing a flow through the spray dispenser. The evaporator is operated as a hybrid falling film heat exchanger, that is, in a semi-flooded condition. The lower portion of the evaporator shell is flooded with liquid refrigerant to wet the lower tubes in the tube bundle while the tubes in the upper portion are wetted only by refrigerant spray from the spray dispenser. The system is operated in a steady state condition whereby at least twenty-five percent (25%) of the tubes in the evaporator operate in a flooded heat transfer mode. The system allows a reduction in the amount of refrigerant charge in the system while at the same time avoiding the use of a recirculating system and pump.

Abstract: A heat exchange apparatus is provided with an indirect evaporative heat exchange section and a direct evaporative heat exchange section. A uniform temperature evaporative liquid is downwardly sprayed into the indirect section to indirectly exchange sensible heat with a hot fluid stream flowing within a series of enclosed circuits which comprise the indirect evaporative heat exchange section. After the evaporative fluid descends through the entire indirect heat exchange section and absorbs heat, it is distributed across fill media within the direct evaporative heat exchange section for cooling. Separate streams of ambient cooling air are simultaneously drawn into each of the heat exchange sections crosscurrently to evaporatively cool the evaporative liquid flowing within each section. The water cooled in the direct heat exchange section is then collected in a sump where it is allowed to mix and resultantly become uniform in temperature before being redistributed.

Abstract: A liquid refrigerant distributor for use within a heat exchanger having a body of heat exchange tubes. The distributor comprises a mesh screen and a liquid refrigerant sprayer. The liquid refrigerant sprayer is adapted to spray refrigerant on the mesh screen. The mesh screen being adapted to pass liquid and vaporous refrigerant but also to direct liquid refrigerant onto the heat exchange tubes.

Abstract: A heat pipe includes: a pipe barrel; and a large number of fins disposed on the peripheral surface of the pipe barrel at least on either a heat collecting section side or a radiating section side, each of the fins is attached to the pipe barrel on a plane perpendicular to the axis of the pipe barrel, and each of the fins is composed of a metal plate and net-like material adhered to both surfaces of the metal plate.A heat exchanger of gas-liquid contacting plate type includes: a plurality of heat transfer plates, disposed vertically at certain intervals, defining air flow passages therebetween which allow air to rise, and each of the plates has a heat medium flowing passage thereinside for allowing a heat medium to flow therethrough while the side surfaces of each of the heat transfer plates, which define the air flow passages, are adhered with nets for allowing a liquid to flow downward along the nets and plates.

Abstract: Compression refrigeration apparatus for removing heat from a heat load using a falling film evaporator, operated with an azeotropic refrigerant and utilizing a spray tree distribution system that distributes a refrigerant film on a heat exchange surface by spraying liquid refrigerant onto a surface and allowing the refrigerant to drip onto the primary heat exchange surface. The apparatus allows for efficient recovery of lubricant deposited in the evaporator without redistributing the lubricant within the evaporator. In an alternative embodiment, liquid refrigerant is sprayed onto a mesh screen where it drips onto the primary heat exchange surface.

Abstract: Compression refrigeration apparatus for removing heat from a heat load using a falling film evaporator, operated with an azeotropic refrigerant and utilizing a vapor-liquid separator, preferably inside the evaporator vessel. In one embodiment, two types of heat exchange surfaces are utilized--one for maximizing the axial distribution of refrigerant film on a heat exchange surface, the other for encouraging liquid refrigerant in contact with a heat exchange surface to boil and evaporate. The apparatus allows for efficient recovery of lubricant deposited in the evaporator without redistributing the lubricant within the evaporator.

Abstract: A heat exchange apparatus is provided with an indirect evaporative heat exchange section and a direct evaporative heat exchange section. A uniform temperature evaporative liquid is downwardly sprayed into the indirect section to indirectly exchange sensible heat with a hot fluid stream flowing within a series of enclosed circuits which comprise the indirect evaporative heat exchange section. After the evaporative fluid descends through the entire indirect heat exchange section and absorbs heat, it is distributed across fill media within the direct evaporative heat exchange section for cooling. Separate streams of ambient cooling air are simultaneously drawn into each of the heat exchange sections to evaporatively cool the evaporative liquid flowing within each section. The water cooled in the direct heat exchange section is then collected in a sump where it is allowed to mix and resultantly become uniform in temperature before being redistributed.

Abstract: A feeder tube (26) for outputting a liquid evenly along its length is formed of an inner tube (40) and an outer tube (42), each having a split (48,50) along at least part of their lengths. The splits (48,50) are positioned away from each other thus allowing liquid in the inner and outer tubes (40,42) through the split (48) in the inner tube (40) and into a gap (44) between the inner and outer tubes (40,42). The liquid is then output from the feeder tube (26) through the split (50) in the outer tuber (42). The feeder tube (26) is incorporated in apparatus for enabling heat transfer between a fluid and an elongate element (22). In the apparatus at least one feeder tube (26) is positioned above and at least in part parallel to the elongate element (22), whereby an even film of the fluid in liquid form is formed on at least a part of the elongate element (22).

Abstract: A heat exchanger for fluids is disclosed having a support assembly for the coil bundle which comprises two vertically spaced-apart support members between which the coil bundle of the exchanger is positioned. The bundle comprises a plurality of vertically spaced tubes each having a number of convolutions which slope upwardly and proceed outwardly to form the bundle. A bridge member having spaced-apart scalloped portions is provided which separate the convolutions of each tube to permit air and water to circulate therebetween. The support members have means for varying the slope of the bridge members depending on the nature of the fluid entering the exchanger.

Abstract: This invention relates to a falling film evaporator which is arranged to cause a liquid film to flow downward to thereby effect heat exchange using evaporation. In a space of an evaporating compartment, a gas-liquid separator is disposed to communicate with a compressor which constitutes a part of a refrigeration cycle.

Abstract: A heat exchange apparatus having a first header for receiving fluid from a source, flexible thin-walled tubular plastic heat exchange elements defining a plurality of passages through a heat exchange zone and second header means for receiving fluid from said plastic heat exchange elements after passing through said heat exchange zone. Support elements are provided, supporting and rigidifying the flexible thin-walled tubular plastic heat exchange member. The plastic heat exchange element defining said plurality of passages is radially expandable by pressure of fluid from said source to avoid scale formation.

Abstract: A heat exchanger comprises a plurality of coil units to form a substantially rectangular prism. Each of the coil units is supported by a pair of supporting frame members through a pair of electrically insulating spacers without direct contact with the supporting frame members.

Abstract: An improved finned heat exchanger tube wherein the upper circumferential portions of the fins are foreshortened to enhance axial movement of liquid introduced onto the top of the finned tube. Accordingly, the liquid can gravitate both axially and circumferentially of the finned tube and thoroughly wet the entire external surface thereof.

Abstract: Set out herein is a solar heating panel adapted to exchange solar heat with fluids, the panel including a translucent upper surface covering the top of a rectangular enclosure, the enclosure further supporting on stand-offs a heat exchange panel. The heat exchange panel is provided with a plurality of tubular segments attached to the exposed surface thereof by which the solar rays received in the panel are reflected repeatedly until absorbed. It is contemplated to convey fluid around the tubular segments, the fluid thus exchanging heat therewith.

Abstract: A cooler for chilling a working fluid used in a manufacturing or production process comprised of a tank having a reservoir in the bottom and one or more cooling coils mounted above the reservoir. A metering plate is inserted in the tank above the cooling coils to distribute the working fluid to be cooled over the refrigerant-containing coil at a predetermined rate. The metering plate has a plurality of tapered metering holes in a circular pattern aligned with each coil of the cooling coils mounted in the tank. The metering holes evenly distribute the hot working fluid over the cooling coils. Distribution and overflow barriers are provided on the metering plate to provide a constant maximum flow of hot working fluid through the cooling tank. Refrigerant is pumped through the cooling coils from the bottom to the top in a counterflow action with respect to the hot working fluid to be cooled.

Abstract: A process for evaporation comprises the step of introducing high-temperature steam successively into separate bundles of horizontal heat-transfer tubes and spraying feed-liquid over the tubes. The number of the tubes in each bundle is smaller than that in the next lower bundle. The steam is first introduced into the tubes of the bottom bundle after cooled by subjection to condensate produced in the tubes of the middle bundle. An evaporator is also disclosed.