JP2015505027A - Modular plate / shell heat exchanger - Google Patents

Abstract

Modular plate-shell heat exchange in which welded heat transfer plate pairs are connected in tandem and spaced in parallel between the inlet and outlet conduits to form a heat transfer assembly vessel. A heat transfer assembly is disposed within the shell to transfer heat from the secondary fluid to the primary fluid. A module comprising one or more heat transfer plates is removably connected via a gasket to inlet and outlet conduits that connect to the primary fluid inlet nozzle and the primary fluid outlet nozzle. Supporting the heat transfer assembly by a structure on an internal track attached to the shell facilitates removal of the heat transfer plate. The modular plate-shell heat exchanger has a removable head integral with the shell to allow removal of the heat transfer assembly for inspection, maintenance and replacement purposes. [Selection] Figure 3

Description

This application is a continuation-in-part of US patent application Ser. No. 12 / 432,147, filed Apr. 29, 2009.
The present invention relates to the modularization of heat exchangers, particularly laminated plate heat exchangers.

  In general, water supplied to a steam generator in a nuclear power plant is preheated before being introduced to the secondary side of the steam generator. Similarly, in the case of non-nuclear power plants, water is preheated before being introduced into the boiler. Usually, a feed water heat exchanger is used for this purpose. Conventionally, heat exchangers are roughly classified into plate-type heat exchangers and tube-shell type heat exchangers. The major difference between these two types in terms of structure and heat transfer is that in one side the heat transfer surface is mainly a plate, while the other is a tube.

  Tube-shell type heat exchangers used in many water heaters employ cylindrical shells that are hemispherical or flat at both ends and are arranged horizontally or vertically. The interior of the horizontal shell is divided by a tube sheet perpendicular to the axis of the shell. More specifically, a water chamber portion including a water injection chamber having a water injection port and a water discharge chamber having a water discharge port is defined on one side of a tube plate at one end of the shell. In the U-shaped tube-shell type heat exchanger, a plurality of heat transfer tubes extending along the axis of the shell from the other side of the tube sheet are bent into a U shape at the respective central portions. Both ends of these heat transfer tubes are fixed to the tube plate, and one end of each heat transfer tube opens into the water injection chamber and the other end opens into the drainage chamber. Another type of tube-shell type heat exchanger uses straight pipes, with a water injection chamber and a drainage chamber at opposite ends. The heat transfer tubes are supported by a plurality of heat transfer tube support plates arranged at an appropriate pitch in the longitudinal direction. A steam inlet / outlet and a drain inlet / outlet are formed in the shell portion where the heat transfer tubes are arranged.

  During operation, the feed water flowing into the feed water heater from the water injection chamber flows in the U-shaped heat transfer tube, thereby absorbing heat from the heated steam flowing into the feed water heater from the steam inlet and condensing the steam. Condensate is collected at the bottom of the shell and discharged outside through the drain at the bottom of the shell. Since the shell and the heat transfer tube are cylindrical, the structure is suitable as a pressure vessel. Therefore, the tube-shell type heat exchanger has been used for ultra-high pressure.

  The biggest drawback of the tube-shell type heat exchanger is that it is heavier than the surface area of the heat transfer surface. Therefore, the tube-shell type heat exchanger is usually large. In addition, it is not easy to design and manufacture a tube / shell type heat exchanger in consideration of heat transfer efficiency, flow rate characteristics, and cost.

  A typical plate heat exchanger is a plate in which rectangular plates with ridges or grooves are pressed against each other by an end plate, and the end plate is fastened to the end of the laminated plate via a fastening screw or a fastening rod. The gap between the plates is closed and sealed by a belt-like seal provided on the outer periphery, but such a seal is also used for the flow path. Since the bearing strength of the supple plate is low, the groove strength of the adjacent plates intersects to increase the bearing strength, while the groove flanges support each other to strengthen the pressure resistance of the structure. . However, the more important point is the significance of the presence of grooves in heat transfer, and the groove shape and the angle of the groove to the flow affect the heat transfer and pressure loss. In a conventional plate heat exchanger, the heat supply medium flows in every other gap between the plates, and the heat receiving medium flows in the remaining gap. Between every other pair of plates, flow is induced through holes provided near the corners of each plate. Each gap between every other pair of plates is without exception two holes surrounded by a closed rim, as well as two holes that serve as inlet and outlet channels for the gap between the plates. including. When a small and lightweight structure is desired, the plate heat exchanger is generally composed of a relatively thin plate. Since the plate can be shaped as required, the heat transfer characteristics can be adapted for almost any application. The greatest weakness of the conventional plate heat exchanger is a seal that restricts the pressure resistance and heat resistance of the heat exchanger. That is, there are cases where the combined use with a corrosive heat supply medium or heat receiving medium is restricted.

  There have been attempts to improve plate heat exchangers by eliminating all seals and employing solder joints or weld seams instead. Plate type heat exchangers manufactured by solder joints or welded joints are almost the same as plate type heat exchangers that employ seals. The most noticeable difference is that there are no fastening screws between the ends. However, with a soldered or welded structure, it is difficult, if not impossible, to disassemble the plate heat exchanger non-destructively for cleaning.

  Attempts have been made to develop heat exchangers that combine the advantages of tube-shell heat exchangers and plate heat exchangers, some of which are similar in both basic types. One of them is disclosed in US Pat. No. 5,088,552, in which circular or polygonal plates are stacked and supported by end plates. The plate laminate is surrounded by a shell provided with inlet and outlet channels for the heat supply medium and the heat receiving medium on both sides. Unlike conventional plate heat exchangers, all fluid into the plate gap flows from the outside of the plate. If the heat exchanger disclosed in this publication is closed by welding, it is possible to obtain the same pressure as in the case of using the tube / shell type heat exchanger, together with the heat transfer performance of the plate type heat exchanger.

  International Publication No. WO91 / 09262 relates to the improvement of the invention of the above publication and states that the features of both the plate-type heat exchanger and the tube-shell type heat exchanger can be exhibited more clearly. The circular plates are laminated in pairs by welding through the rims of the holes that form the inlet and outlet channels. A closed circuit for flowing one heat transfer medium is obtained by collectively welding the plate pairs obtained in the above-described manner along the outer peripheral edge of the plate. Unlike a conventional plate heat exchanger, this structure is welded and only two holes are formed in the plate. The other heat transfer medium is directed through the shell surrounding the plate stack to all other gaps between the plates. A seal is employed to prevent flow from flowing between the plate stack and the shell, but this seal is primarily used as a deflector for the flow. Obviously, pressure resistance is not required for this deflector. It is difficult to employ a seal because of the structure of the plate laminate. For example, it may be appropriate to use an elastic rubber gasket instead of a seal so that the heat exchanger can be disassembled for cleaning.

  A common design problem with shell-and-tube heat exchangers currently used by nuclear power plants is that if the tubes deteriorate, the only option is to plug the damaged tubes to minimize leakage. As a result, the thermal duty may be reduced. Lowering the thermal duty in the water supply system is costly for nuclear power plants and eventually requires replacement of the shell-and-tube water heater. Another problem with the shell-and-tube heat exchanger design is that it is difficult to detect corrosion / erosion / damage because shell-side inspection is often limited to small hand holes and inspection ports. Significant corrosion / erosion can occur in the internal baffle, resulting in (1) degradation of flow bypass and thermal performance, and (2) tube wear due to vibrations caused by flow. Significant corrosion / erosion has also been observed on the shell inner surface of the shell-and-tube water heater.

  In light of this situation, the design of a novel water heater that can maintain the thermal duty over a long period of time and maintain the soundness of structural components over a long period of time compared to existing shell / tube type water heaters. desired. It would be desirable to be able to maintain the thermal duty over a long period of time without replacing the heat transfer surface, if necessary, by replacing or repairing the heat transfer surface. Furthermore, it is desirable to be able to increase the heat transfer capacity of the feedwater heater without replacing the entire feedwater heater in order to cope with improved efficiency of the power plant.

  The above objects are achieved in a nuclear power plant by a modular plate-shell water heater with a pair of heat transfer plates welded in the shell to transfer heat from drain flow and extracted steam to the feed water. Heat transfer plate pairs, or groups of heat transfer plate pairs joined by welding or other means, i.e. modules of the heat transfer plate pairs are arranged in tandem and at least some of the modules are connected via gaskets, And a common inlet conduit and outlet conduit connected in parallel to the outlet nozzle, respectively. Preferably, the heat transfer assembly formed by the inlet conduit, outlet conduit and heat transfer plate pair is mounted on an internal track mounted within the shell and supported by a structure movable along the track. This facilitates the removal of the heat transfer plate. The modular plate-shell water heater has a removable head integral with the shell for removing the heat transfer plate for inspection, repair or replacement purposes. It is preferable that the inlet and outlet nozzles are inserted and sealed through the removable lid.

  The heat exchanger described herein preferably includes means for improving the heat transfer capacity after a certain period of time in order to improve the performance of the power plant in which the heat exchanger is installed. In one embodiment, the inlet and outlet conduits include a number of supplemental attachment points for a pair of heat transfer plates that are initially sealed. In another embodiment, the inlet and outlet conduits can be expanded by adding heat transfer plate pairs or modules. In the latter embodiment, initially, a spacer module with little or no heat transfer capability is supported in tandem with the heat transfer plate module of the heat exchanger. At a later date, the heat transfer capability of the heat exchanger can be improved by replacing the spacer module with a heat transfer plate module. It is desirable that repair or replacement be facilitated by making at least a part of the connecting portion between the heat transfer plate pairs or modules formed by joining the heat transfer plate pairs detachable. Preferably, the modules are connected by tie rods, but in embodiments where the inlet and outlet conduits extend between the modules, compressing force is applied by the tie rods to press the interface between the conduit segments of the facing modules, Form a liquid tight seal.

  Preferably, the heat transfer assembly can be removed from the removable shell of the head. Alternatively, the shell is provided with a manway for accessing the interior of the shell to disconnect the feed inlet nozzle from the feed inlet conduit and the feed outlet conduit from the feed outlet nozzle. Alternatively, both of these options may be provided.

  Desirably, there is a support panel at each end of the module and a tie rod extends between the support panels. The heat transfer plate pair is sandwiched between support panels, and in one embodiment, a primary fluid inlet conduit and a primary fluid outlet conduit pass through the module. The support panel is preferably thicker than the heat transfer plate. In one embodiment, the heat transfer plates between the support panels are welded to each other and to the support panels so that adjacent support panels are mechanically connected to each other.

  The present invention also provides a method for cleaning or repairing a feedwater heater comprising the following steps: accessing the interior of the pressure vessel shell; removing at least one pair of heat transfer plates from the assembly of heat transfer plates; Clean, repair or replace the plate pair; reconnect the cleaned, repaired or replaced heat transfer plate pair to the heat transfer assembly. Preferably, the removable head is removed in the step of accessing the pressure vessel, and the pair of heat transfer plates is removed from the feed water inlet conduit and the feed water outlet conduit in the step of removing the at least one heat transfer plate pair.

  The present invention also includes a method for repairing, inspecting, cleaning or improving the performance of a water heater having a pressure vessel with a removable head. The method includes the following steps: With the heat transfer assembly present in the pressure vessel, the removable head is removed or otherwise accessed inside the pressure vessel; a feed inlet conduit and a feed outlet conduit Separate from the water inlet nozzle and water outlet nozzle respectively. The method further includes exchanging defective heat transfer plate pairs and increasing the number of heat transfer plate pairs in order to improve the performance of the heat exchanger after the heat exchanger is operated.

  The details of the invention will now be described by way of example with reference to the accompanying drawings.

It is an elevation view which shows the water heater of one embodiment of this invention.

It is a top view of the water heater of this invention shown in FIG.

It is a perspective view which shows another embodiment of the water heater of this invention which decomposed | disassembled the heat-transfer assembly into the module and removed some from the shell.

FIG. 4 is a perspective view showing one of the end heat transfer plate pair modules of the embodiment shown in FIG. 3.

It is a perspective view which notches and shows a part of heat-transfer assembly shown to FIG.

It is a flow schematic diagram of the primary fluid which passes along the feed water heater of the embodiment shown to FIGS. 3-5.

It is a side view of a heat-transfer plate pair.

1 is a schematic view of one embodiment of a heat transfer plate module. FIG.

It is a schematic diagram of the 2nd embodiment of a heat-transfer plate module.

It is sectional drawing of a spacer module.

FIG. 5 is a partial cross-sectional side view of a segment of a tie rod used to connect two heat transfer plate modules.

  The water heater designed by the nuclear power plant currently uses a shell-and-tube heat exchanger. Another common type of heat exchanger that has been in use since 1923 is the plate frame type heat exchanger. The latter is characterized by a compact design, high heat transfer coefficient, high fluid pressure drop in the plate, and is generally limited to low pressure fluids. The embodiment described herein is an optimized combination of the characteristics of a plate-frame heat exchanger and a conventional shell-and-tube heat exchanger, which facilitates maintenance and inspection, and provides heat transfer capability as desired. Provided is a plate / shell type water heater which can be easily and relatively inexpensively changed in design.

  A water heater 10 according to an embodiment of the present invention is shown in an elevation view in FIG. 1 and a top view in FIG. The two heat transfer plates 12 and 14 are welded so as to form a weld plate pair 16 in which a flow path of the water supply fluid is formed between the plates as in the conventional plate heat exchanger. In one embodiment, the heat transfer plate pair 16 is in fluid communication with one end at the inlet header pipe 22, the other end at the outlet header pipe 24, and the inlet and outlet header pipes 22, 24, respectively. For example, it is detachably connected via a gasket 18 and a bolted flange joint 20. A number of such welded heat transfer plate pairs 16 are arranged in tandem at spaced intervals, each connected between an inlet header and an outlet header to form a heat transfer assembly having parallel flow paths. Such a configuration is shown in FIG. A number of heat transfer plate pairs 16 may be connected in series, and both ends of this series configuration may be detachably attached to the inlet header pipe 22 and the outlet header pipe 24, respectively, as in the above configuration. In either embodiment, the ends of the heat transfer plate pair 16 are directly or indirectly connected to the inlet header pipe 22 and the outlet header pipe 24. The inlet header pipe 22 and outlet header pipe 24 are preferably bolted, preferably including a gasket, similar to the previously described embodiment that removably secures the heat transfer plate pair 16 to the inlet and outlet header pipes 22,24. It is connected to the water supply inlet nozzle and the water supply outlet nozzles 26 and 28, respectively. However, other detachable connecting means can be used.

  In the embodiment shown in FIGS. 1 and 2, the header pipes 22, 24 are supported by a frame structure 30 mounted on an inner track 32 attached to the lower portion of the cylindrical shell 34, and the cylindrical shell Forms a pressure vessel surrounding the heat transfer plate assembly 36. The wheels 32 on the track 32 and the frame structure 30 facilitate the task of removing the heat transfer plate assembly from the shell for repair, cleaning or capacity enhancement. In one embodiment, the shell has a hemispherical end 38 integral therewith on one side and a removable hemispherical head 40 at the other end, and the cylindrical shell 34, hemispherical end 38 and removable. The heat transfer assembly 36 is completely enclosed and sealed within the pressure vessel formed by the flexible head 40. In utilizing the present invention, both end portions are not necessarily hemispherical, but it is preferable that both end portions be hemispherical when handling high pressure. As shown in FIGS. 1 and 2, the water supply inlet nozzle 26 and the water supply outlet nozzle 28 penetrate the removable head 40. Alternatively, the hemispherical end 38 can be removed instead of the head 40 or the hemispherical end 38 to facilitate access to the interior of the shell 34 for repairing the heat transfer plate assembly 36. It is also possible to connect both the head 40 and the head 40 to the shell 34 by bolting the flange. Also attached to the shell 34 are an extraction steam inlet 42, drainage inlets 44, 46 and drainage outlets 48, 50.

  In operation, incoming feed water is fed through an inlet nozzle 26, an inlet header pipe 22, welded heat transfer plate pair 16, outlet header pipe 24 and outlet nozzle 28 where the feed water is heated by drain flow and extraction steam. pass. As the extraction steam enters the feedwater heater from the extraction steam inlet 42, it is distributed by the steam buffer plate 52 and mixes with the drain flow flowing from the drain flow inlet nozzles 44, 46 while passing through the upper shell region. The extracted steam and drain flow then pass between the welded heat transfer plate pair 16, cooled by the feed water, condensed and flow to the lower region of the shell and discharged from the drain flow outlet nozzles 48, 50. .

  During the power plant outage, the heat transfer plate and the inner surface of the shell can be inspected using the following steps. First, the bolt of the flange 54 is loosened and the shell end 38 is removed. The header pipes 22, 24 are then removed from the inlet and outlet nozzles 26, 28. A manway 56 provided on the head 40 provides access to the connection between the inlet and outlet header pipes 22, 24 and the inlet and outlet nozzles 26, 28. When the head 40 is removed at the position of the flange 58, the inlet and outlet headers 22 and 24 and the feed water inlet and outlet nozzles are moved by sliding the heat transfer assembly 36 on the track 32 and moving the head 40 outward. 26 and 28 can be accessed. Prior to moving the head 40, spool piping (not shown) must be removed from the inlet and outlet nozzles 26,28. Next, the heat transfer plate assembly 36 is moved as a unit along the track 32 provided at the bottom of the shell 34 to a position where damage inside the individual heat transfer plates 12 and 14 and the shell 34 can be inspected. Thus, individual heat transfer plate pairs 16 can be cleaned and repaired or replaced if necessary. If repair or replacement is required, remove problematic heat transfer plate pair 16 from inlet header pipe 22 and outlet header pipe 24 and replace with new or repaired heat transfer plate pair 16 and bolt in place do it. One or more separate openings 60 are provided in the outlet header pipe 24 and the inlet header pipe 26 and are initially sealed with plugs. If these other openings are unsealed, they become openings for attaching another heat transfer plate pair 16 in the future when performance needs to be improved.

  By designing the plate to be removable, the heat transfer surface can be replaced and the heat transfer plate and gasket can be mass-produced, resulting in cost reduction of important spare parts. By adopting this design, the number of plates, and hence the heat transfer area, can be expanded to cope with the improvement in output and further enhance the inspection related to the shell.

  While specific embodiments of the invention have been described in detail, it will be apparent to those skilled in the art that various changes and alternatives can be made in the details in light of the entire disclosure. For example, while the embodiment shown in FIGS. 1 and 2 discloses a configuration in which the inlet and outlet header pipes or conduits are separated, other structures that perform similar functions without departing from the spirit of the present invention are employed. be able to. For example, in the embodiment shown in FIGS. 3, 4, and 5, the segments of inlet conduit 22 and outlet conduit 24 of heat transfer assembly 36 are integral with heat transfer plate pair 16. 3, 4, and 5, constituent elements corresponding to those shown in FIGS. 1 and 2 are denoted by the same reference numerals. In the embodiment shown in FIGS. 3, 4 and 5, the heat transfer assembly 36 is constituted by a number of heat transfer plate modules 17. FIG. 5 shows four such heat transfer plate modules 17. The module 17 includes a plurality of heat transfer plate pairs 16 that are spaced apart from each other in the vertical direction, and these heat transfer plate pairs are joined to form an integral unit. Each of the modules 17 shown in FIGS. 3, 4 and 5 has about 10 such heat transfer plate pairs 16. Here, the number of heat transfer plate pairs may be arbitrary, but it should be recognized that the module replacement cost increases as the number of heat transfer plate pairs per module increases. However, as the number of modules increases, the cost required for gaskets and sealing devices increases. The optimal number of plates per module should be determined for each application from an economic point of view. The number of modules 17 in the heat transfer assembly 36 may also vary depending on the number of heat transfer plate pairs 16 per module and the heat transfer requirements depending on the heat exchanger application.

  In the embodiment shown in FIGS. 3, 4, and 5, two openings are provided on the outer surface (ie, front and back) of each heat transfer plate pair 16. Corresponding apertures are substantially aligned, and incremental segments of inlet and outlet conduits 22, 24 are joined to the apertures by welding, brazing, or other suitable method, between the heat transfer plate pairs 16. This portion also forms a substantially rigid and durable joint that is substantially impermeable to fluid flowing in and around the inlet and outlet conduits 22,24. Incremental segments of the inlet and outlet conduits 22, 24 extending between the heat transfer plate pair 16 and the outer surface of the adjacent heat transfer plate pair 16 provide flow paths for extraction steam and drain flow between the heat transfer plate pairs 16. I will provide a. It is preferred to provide flanges at the outer ends of the inlet and outlet conduits 22, 24 through each module 17, on which the corresponding flanges of the segments 23 of adjacent heat transfer plate modules, preferably between the flanges. Press-fit the gasket to connect. The outer segment 23 of each module 17 is then attached to the corresponding outer segment of the adjacent module using a tie rod 64 shown in FIGS. However, other mechanical attachment means may be used in place of the tie rod. In the embodiment shown in FIGS. 3, 4, 5, the module 17 is held in place by pulling the front and back frames or plates 62 together by tie rods 64. The surface plate 62 of the heat transfer plate assembly has openings for inlet and outlet conduits 22, 24 so that the flanges of the outer segment 23 can be attached to the inlet nozzle 26 and outlet nozzle 28 (shown in FIG. 2), respectively. . The inlet and outlet on the outer heat transfer plate 36 at the end 80 of the heat transfer assembly 36 is sealed to close the feed flow loop or the inlet and outlet holes in the rear heat transfer plate. Do not provide.

  Although the heat transfer plate assembly of the embodiment described above has parallel flow paths through the heat transfer plate pair 16, FIG. 6 schematically illustrates the flow of primary fluid through the heat transfer plate assembly. FIG. 7 shows the configuration of the heat transfer plate pair. As shown in FIG. 7, a weld bead 66 extends around each incremental segment 23 of the inlet conduit 22 at a corresponding opening in the heat transfer plates 12, 14 to form a fluid seal at the interface. Similarly, the weld bead 68 extends around the incremental segment 23 of the outlet conduit 24 at a corresponding opening in the heat transfer plate 12, 14 to form a fluid seal at the interface. Further, the girth welded portion 70 extends over the entire periphery of the heat transfer plate pair 16. As shown in FIG. 7, the primary fluid flows into the inlet 72 of the inlet conduit 22 that connects each heat transfer plate pair 16 to an adjacent heat transfer plate pair or support plate. Part of the primary fluid flows down between the heat transfer plates 12, 14 where it absorbs heat from the extracted steam and drain flow that flows outside the heat transfer plate pair and then flows out of the outlet 78 to the outlet conduit 24. Then, it merges with the flow of the primary fluid that has entered the heat transfer plate pair 16 from the inlet 76 of the outlet conduit and goes upstream from the other heat transfer plate pair. Except for the last heat transfer plate pair 16 at the end 80 (FIG. 5) of the heat transfer assembly 36, it entered through the inlet 72 of a given heat transfer plate pair 16 but did not flow between the heat transfer plates 12,14. The remaining primary fluid flows from the inlet conduit outlet 74 to the adjacent heat transfer plate pair 16. Any primary fluid that passes through the inlet conduit and reaches the end 80 of the heat transfer assembly 36 flows between the last pair of heat transfer plates 12, 14 and then exits the outlet conduit 24 as shown in FIG. To do. If the flow is from the inlet conduit 22 to the outlet conduit 24, the water flowing through the heat transfer plate pair 16 is upward (as shown in FIG. 6), downward (as described herein), or sideways. Even that is not important.

  FIG. 8 is a schematic view of one embodiment of the heat transfer plate module 17. Although the illustrated module 17 includes four heat transfer plate pairs 16, as described above, the number of heat transfer plate pairs 16 may be changed. The heat transfer plates 12 and 14 on the outer side of the heat transfer plate pair 16 are relatively thin compared to the support plate 82, so that the outer support plate 82 is thicker than the inner heat transfer plate pair 16. Support plate 82 is the longest of what is referred to as a support plate, and is long enough to receive the tie rods shown in FIGS. This embodiment is slightly different from the embodiments shown in FIGS. However, although the method for fixing the modules to each other is the same, other fixing means, for example, a rod or bolt having a continuous thread can be used. The inner heat transfer plates are welded together so that the incremental segment 23 of the conduit (shown in FIG. 4) extends between them, but around the circular openings of the incremental segments of the inlet and outlet conduits 22, 24. However, the outer peripheral plate-like welded portion 70 extends to the outer edge portion. A gasket groove 84 is provided around the openings of the inlet and outlet conduits 22, 24 of the support plate 82 so that the gasket seals the opening at the interface with the engaging support plate 82 of the adjacent module 17.

  FIG. 9 shows a second embodiment of the heat transfer plate pair module 17. The embodiment shown in FIG. 9 is very similar to that described with respect to FIG. 8, except that there is a gasket retaining ring 86 around the opening of the inlet and outlet conduits 22, 24 of the outer heat transfer plate. A single support plate is inserted between the module 17 and the gasket on the retaining ring 86 to seal the openings 22, 24 between each support plate and the heat transfer plate. Or you may provide the groove | channel which hold | maintains a gasket in the one side or both sides of a support plate.

  In the future, if it is necessary to increase the heat transfer capacity of the existing shell to improve the performance of the power plant where the heat exchanger is installed, the spacer module 88 may be used instead of the heat transfer plate pair module 17. By inserting, you may make it ensure the space for adding another heat-transfer plate pair 17 module at a later date. One embodiment of such a spacer module 88 is shown in FIG. Preferably, the spacer module 88 is the same size as the standard heat transfer plate pair 17 module of the heat exchange unit 10 employed. The spacer module of this embodiment has two support plates 82 with gasket grooves 84 as described above, which support plates include an upper support 96 and a lower support 98 having a secondary fluid drain 94. Separated by The upper support 96 and lower support 98 may be part of one continuous support cylinder (although it is not essential). Assuming that the embodiment shown in FIG. 10 is inserted between the heat transfer plate pair module 17, the pipe 90 is welded at its interface with each support plate to form a hermetic seal. The pipe 90 forms part of the inlet conduit 22 and carries the primary fluid between the heat transfer plate pair module 17 to which the pipe connects. Similarly, a pipe 92 welded to the support plate 82 of the spacer module 88 connects between the support plates and carries the primary fluid through the outlet conduit 24. When a spacer is used at the end 80 of the heat transfer plate assembly 36, no opening is required in the spacer module support plate 82.

  FIG. 11 shows one embodiment of a tie rod that can be used to pull modules 17 and 88 together. The tie rods 64 are designed to extend between the support plates 82 as well as between the support frames 62 shown in FIG. In the embodiment shown in FIG. 11, one end of the tie rod 64 is reduced in diameter and a screw 104 is cut on the peripheral surface. The supporting surface 106 where the peripheral surface screw 104 terminates is sized to abut on the periphery of the hole provided on the side surface of the peripheral portion of the module support plate, but the screw 104 is sized to protrude through the hole to the opposite side. An internal thread 100 is provided at the opposite end of the tie rod 64 and is sized to be screwed with the external thread 104 of the adjacent tie rod 64 that passes through a corresponding hole in the adjacent support plate 82. The outline of the outer peripheral portion 102 on the side having the female thread 100 of the tie rod is preferably square or hexagonal so that torque can be easily applied.

  As described above, the heat transfer plate assembly 36 includes the wheels 33 placed on the track 32 in order to facilitate maintenance and inspection. The maintenance of this embodiment is similar to that shown in FIG. 1 except that the spacer module 88 is removed and another heat transfer plate module 17 is connected instead to improve the performance of the heat transfer plate assembly. 2 is the same as the embodiment shown in FIG.

Moreover, although the preferable embodiment for water heaters has been described, beneficial results can be obtained even when the present invention is applied to various other types of heat exchangers. Accordingly, the specific embodiments disclosed above are for illustrative purposes only and are not intended to limit the scope of the invention, which is limited by the appended patentability and equivalents thereof. It is determined by.

Claims (20)

A heat exchanger (10),
Removable lid (40) provided at one end of the axial dimension, primary fluid inlet (26), primary fluid outlet (28), secondary fluid inlet (42, 44, 46), drain outlet (48 50) and an elongated pressure vessel shell (34) having a heat transfer assembly (36),
The heat transfer assembly (36)
A primary fluid inlet conduit (22) extending from the primary fluid inlet (26) into the pressure vessel (34);
A primary fluid outlet conduit (24) extending from the primary fluid outlet (28) into the pressure vessel (34);
Each pair is sealed (70) along the periphery to define a primary fluid flow path between the first and second plates (12, 14) and directly to the primary fluid inlet conduit (22). Or tandemly supported, having an opening in the heat transfer plate inlet (72) connected indirectly and an opening in the heat transfer plate outlet (78) connected directly or indirectly to the primary fluid outlet conduit. A plurality of heat transfer plate pairs (16),
The plurality of heat transfer plate pairs (16) are arranged in units of modules (17), and at least one of the modules is connected to adjacent modules, primary fluid inlets, non-destructively removable mechanical connections (84), Or a heat exchanger (10) connected in cascade with the primary fluid outlet.   The heat exchanger (10) of claim 1, wherein at least some of the modules (17) include a plurality of heat transfer plate pairs (16).   The heat exchanger (10) of claim 1, wherein the heat transfer assembly is accessed via a removable lid (40) for maintenance.   The heat exchanger (10) of claim 3, wherein the heat transfer assembly (36) can be removed from the pressure vessel shell (34) by opening the removable lid (40).   The heat exchanger (10) according to claim 4, wherein when the removable cover (40) is opened, the heat transfer assembly (36) can be slid out of the pressure vessel shell (34).   As a unit from the pressure vessel by moving the heat transfer assembly along the track by movably supporting the heat transfer assembly (36) on a track (32) attached to the pressure vessel (34). The heat exchanger (10) according to claim 1, wherein the heat exchanger (10) can be taken out via the one end (40).   The heat exchanger (10) according to claim 6, wherein the heat transfer assembly (36) is supported on wheels (33) mounted on the track (32).   The heat exchanger according to claim 1, wherein the primary fluid inlet (26) and the primary fluid outlet (28) extend from a removable lid (40).   The heat exchanger (10) of claim 1, including means for extending the heat transfer capacity of the heat transfer assembly (36).   The heat transfer assembly (36) was provided with an extra connection (60) for attaching to another heat transfer plate pair (16), and initially the extra connection was sealed and the heat exchanger was operated. The heat transfer capacity of the heat exchanger according to claim 9, wherein it is possible to improve the heat transfer capacity of the heat exchanger by opening at least some of the extra connecting parts and attaching another heat transfer plate thereto. Exchanger (10).   The heat exchanger (10) of claim 9, wherein the means for extending the heat transfer capacity of the heat transfer assembly (36) comprises a spacer module (88) in cascade with a module (17) of heat transfer plate pairs. ).   The heat exchanger (10) according to claim 1, wherein the pressure vessel shell (34) is cylindrical and has hemispherical ends (40, 38). A method for cleaning or repairing a heat exchanger (10) according to claim 1, comprising:
Accessing the interior of the pressure vessel shell (34);
Removing at least one pair of heat transfer plates (16) from the heat transfer assembly (36);
Clean, repair or replace the removed pair or pairs of heat transfer plates (16);
A method for cleaning or repairing a heat exchanger (10) comprising the step of reconnecting a pair or pairs of heat transfer plates (16) cleaned, repaired or replaced to a heat transfer assembly (36).   In the step of accessing the interior of the pressure vessel shell (34), the removable lid (40) is removed from said one end or the pressure vessel shell manway (56) is opened to provide at least one pair of heat transfer plates The heat exchanger (10) cleaning or removal according to claim 13, wherein in the step (16) of removing, at least one pair of heat transfer plates is removed from the primary fluid inlet conduit (22) and the primary fluid outlet conduit (24). Repair method. A method of repairing, checking, cleaning or improving the performance of the heat exchanger (10) according to claim 1,
Accessing the interior of the pressure vessel shell (34);
Removing the primary fluid inlet conduit (22) and the primary fluid outlet conduit (24) from the primary fluid inlet (26) and the primary fluid outlet (28), respectively.   14. The method according to claim 13, comprising the step of replacing the defective heat transfer plate pair (16).   16. The method of claim 15, further comprising increasing the number of heat transfer plate pairs (16) in the heat transfer assembly (36) to increase the performance of the heat exchanger after operating the heat exchanger (10). the method of.   The heat exchanger (10) according to claim 1, wherein at least some of the modules (17) comprise a plurality of heat transfer plate pairs (16), each pair in the module being connected in cascade by a weld joint (23). .   At least some of the modules (17) have support plates (82) at first and second ends sandwiching a heat transfer plate (12, 14) therebetween, the support plate being thicker than the heat transfer plate. The heat exchanger (10) according to 1. The heat exchanger (10) according to claim 1, wherein the modules (17) are supported in tandem by tie rods (64).

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