JP5690532B2 - Shell and plate heat exchanger - Google Patents

Description

  The present invention relates to a shell-and-plate heat exchanger which is suitable for being applied to an evaporator of a refrigeration apparatus constituting a refrigeration cycle and has a plate end shape suitable for plasma arc welding.

In a refrigeration system in which an evaporator, a compressor, a condenser, and an expansion device are interposed in a refrigerant circulation path to constitute a refrigeration cycle, NH ₃ and CO that are natural refrigerants are used from the viewpoint of ozone layer destruction and global warming prevention. ₂ etc. are attracting attention. In particular, since NH ₃ has a large refrigerating capacity, it is often used for a large-sized refrigerating apparatus. However, since NH ₃ is toxic, a refrigeration apparatus that combines a secondary refrigerant system that uses CO ₂ as a secondary refrigerant on the cooling load side is often used for refrigeration cycle components that use NH ₃ . . Such NH ₃ / CO ₂ refrigeration apparatuses are disclosed in, for example, Patent Document 1 and Patent Document 2.

In the NH ₃ / CO ₂ refrigeration apparatus, the size of the CO ₂ liquefier used as a cascade condenser increases in the longitudinal direction, and the size of the refrigeration unit must be increased accordingly. Therefore, the CO ₂ liquefier may not be placed on an elevator such as a refrigerated warehouse at the time of carry-in / installation, which may hinder the carry-in / installation.

  On the other hand, the shell-and-plate heat exchanger forms a geometrical flow path on the front and back surfaces by alternately stacking a large number of plates having specific uneven patterns on the front and back surfaces. Thereby, the flow paths of the two heat exchange fluids are alternately formed on the front and back surfaces of the plate, and heat is exchanged between the two heat exchange fluids via the plate. In the flow path, a strong turbulent flow of the flowing fluid is formed. Therefore, the shell-and-plate heat exchanger has the advantages of being able to obtain excellent heat exchange efficiency, shortening the size in the longitudinal direction, and reducing the installation space, and is often used for evaporators and condensers of refrigeration equipment. It has been. Hereinafter, a configuration example of the shell and plate heat exchanger disclosed in Patent Document 3 (FIG. 4) will be described with reference to FIG.

  In FIG. 12, the shell and plate heat exchanger 100 includes a plate polymer 104 accommodated in a hollow container 102. The plate polymer 104 is configured by overlapping a plurality of plates 106 which are heat transfer elements. Between the plates, a passage A opened to the internal space s1 of the hollow container 102 and a passage B closed to the internal space s1 are alternately formed. The first heat exchange fluid a flows into the internal space s1 from the inlet pipe 108 provided at the bottom of the hollow container 102, passes through the passage A, and is discharged from the outlet pipe 110 to the outside of the hollow container 102.

  Each plate 106 is provided with two holes 112 and 114 at positions that are 180 degrees out of phase with respect to the center point in the vicinity of the outer periphery of the plate, and through the holes, 2 holes 2 in a direction penetrating the plate polymer 104. A book channel is formed. An inlet pipe 116 is provided on the side wall of the hollow container 102 at a position opposite to the hole 112, and an outlet pipe 118 is provided on the side wall opposite to the inlet pipe 116 and at a position opposite to the hole 114. The second heat exchange fluid b flows from the inlet pipe 116, and the second heat exchange fluid b reaches the hole 114 from the hole 112 through the passage B and flows out from the outlet pipe 118.

When the first heat exchange fluid a flows through the passage A, the first heat exchange fluid a exchanges heat with the second heat exchange fluid b, and a part thereof is vaporized. The first heat exchange fluid a in the gas-liquid two-phase state is a separator. Gas-liquid separation is performed at 120. When the second heat exchange fluid b flows through the passage B, the second heat exchange fluid b exchanges heat with the first heat exchange fluid a and condenses, and is separated into a condensate and a noncondensable gas by the aftercooler 122. Note that the outer shape of the plate 106 is usually rectangular or circular.

  FIG. 13 shows a structural example of a plate polymer using a circular plate. In FIG. 13, the circular plate 130 is formed with linear corrugated irregularities 132 having corrugated cross sections. In the plate 130, two holes 134 and 134 having a phase difference of 180 degrees with respect to the center are formed in the vicinity of the plate outer peripheral edge 136. The outer peripheral edge 136 of the plate 130 and the inner peripheral edge 138 of the hole 134 are formed on a narrow annular flat surface connected to the corrugated irregularities 132. The plate-like body forming the flat surface of the outer peripheral edge 136 and the plate-like body forming the flat surface of the inner peripheral edge 138 are provided with a height difference corresponding to the level difference between the peaks and valleys of the corrugated unevenness 132.

  The two plates 130 are overlapped with their back surfaces facing each other (with the concavo-convex pattern back to back), and the inner peripheral edges 138 of the holes 134 in contact with each other are circumferentially welded as indicated by the arrow u, The plate 140 is manufactured. At this time, a gap s is formed between the outer peripheral edges 136 of the plate 130 that is twice the level difference between the peaks and valleys of the corrugated irregularities 132 formed on the plate 130. Next, a large number of pair plates 140 are overlaid, the outer peripheral edges 136 of each pair plate 140 are brought into contact with each other, and the contact surfaces are circumferentially welded as indicated by arrows v. Thus, the plate polymer 142 is formed. The plate polymer 142 is fixed inside the hollow container by a support.

  Thus, the outer periphery 136 of the plate 130 and the inner periphery 138 of the hole 134 are selectively welded to the plate polymer 142. That is, the outer peripheral edge and the inner peripheral edge are alternately welded in the polymerization direction. As a result, the first flow path opened to the internal space of the hollow container and the internal space of the hollow container are blocked between the plates and communicated with the hole 134, and from the hole 134 to the outside of the hollow container. A second flow path communicating with is formed. And two heat exchange fluids which flow through the 1st channel and the 2nd channel are heat-exchanged via a plate.

Japanese Patent No. 4188971 Japanese Patent No. 4465686 JP-A-64-88099 (FIG. 4)

As described above, there is a problem that the size of the CO ₂ liquefier incorporated in the NH ₃ / CO ₂ refrigeration apparatus increases in the longitudinal direction, and the size of the refrigeration unit is restricted by this and cannot be reduced. For this reason, when the CO ₂ liquefier is carried in and installed, it may not be put on an elevator such as a refrigerated warehouse, which may hinder the carrying in and installation.

  In order to solve this problem, it is preferable to use a shell-and-plate heat exchanger that has a short size in the longitudinal direction and can reduce installation space. However, the shell-and-plate heat exchanger has many welding locations where the plates constituting the plate polymer are welded, and the number of welding steps increases. For this reason, if a welding failure occurs at any welding location, leakage of the heat exchange fluid occurs, so care must be taken not to generate a welding failure during welding.

  However, since the plate is press-molded into a complicated shape, distortion is likely to occur after press-molding, and the deformation caused by this distortion may reduce the rigidity of the plate polymer. Further, a springback may occur, causing reverse warping in the plate-like bodies forming the outer peripheral edge of the plate or the inner peripheral edge of the plate, and there is a possibility that a gap is generated between the plate-like bodies. When a gap is generated between the plate-like bodies, when arc welding or the like is performed, heat input to the material by the arc becomes unstable, and there is a possibility that poor welding occurs.

  Further, stainless steel having corrosion resistance is usually used as a material for the plate. However, when TIG welding or the like is used, TIG welding is not so good in heat concentration and has a large amount of heat input. Therefore, depending on the material, the base material of the plate may be altered, or thermal deterioration, thermal distortion, and thermal stress may occur. It may occur and the strength of the plate polymer may decrease.

  In view of the problems of the prior art, the present invention, when manufacturing a shell-and-plate heat exchanger, has poor welding due to distortion after plate press forming, springback, etc., and deterioration due to alteration of the plate base material. The purpose is to improve the strength of the plate polymer.

In order to achieve this object, the present invention provides:
Inside the hollow container (12) having a cylindrical shape is provided with a plate polymer (14 ) in which a large number of plates having corrugated cross-sections formed in parallel on the front and back surfaces are superimposed,
Each plate (16) constituting the plate polymer (14) is in a position facing an adjacent plate, and each plate (16) includes a plate outer peripheral edge (16a) and the plate polymer (14). And the inner peripheral edge (22a, 24a) forming the outer peripheral edge (16a) and the hole (22, 24) are flat annular plates. The region excluding these is formed of a plate-like body on which corrugated irregularities (16b) are formed,
The plate-like body is formed so as to have tapered surfaces (46, 48) inclined in a direction approaching each other toward the end side of the outer periphery of the plate and the inner periphery of the plate forming the hole. The plate outer peripheral edge of adjacent plates and the tapered surface end side w of the inner peripheral edge of the plate are fixed by plasma arc welding,
A nozzle tube (36) is arranged in the longitudinal direction of the hollow container (12) in the upper region of the hollow container above the plate polymer (14) in the internal space of the hollow container (12), and the nozzle tube (36) The second refrigerant is jetted toward the plate polymer from a number of nozzle ports (38) arranged in the longitudinal direction and opened downward in the lower part, and the nozzle port (38) is located outside the hollow container (12). The second refrigerant liquid pipe (42) is connected to the pipe line (40) led to, and the second refrigerant liquid circulates between the nozzle pipes (36).
On the other hand, a first channel (26) and a second channel (28) are formed in the direction penetrating the plate polymer (14 ) by the holes (22, 24) , and the first side wall of the hollow container The inlet pipe (30) into which the first refrigerant flows in a position opposite to the flow path (26), and the outlet pipe from which the first refrigerant liquid flows out to a position opposite to the second flow path (28). (32) is provided. Preferably, the outlet pipe (32) penetrates the partition wall of the hollow container (12) as described in claim 2. The shell and plate heat exchanger according to claim 1, wherein the shell and plate heat exchanger is configured to be connected to the second flow path (28).

  In the device of the present invention, the plate-like bodies forming the outer peripheral edge and the inner peripheral edge of the plate are provided with tapered surfaces in a direction approaching each other toward the end side, and the end sides reliably come into contact with each other when fixed on the end side, and They are pressed together. As a result, the distortion generated in the plate can be suppressed, and the reverse warp of the plate-like body due to the spring back or the like can be eliminated. Therefore, welding defects can be eliminated, and the rigidity of the plate polymer can be increased by making the plate-like body a tapered surface, compared to the case where the plate-like body is a parallel surface.

  In the device of the present invention, the taper angle of the taper surface of the plate-like body is 1.5 to 2.0 degrees with respect to the plate surface at the outer peripheral edge of the plate, and the taper angle of the taper surface of the plate-like body is the plate inner peripheral edge. It is good to be 1.0 degree or less with respect to the surface. By setting the taper angle of the plate-like body to 1.5 to 2.0 degrees at the outer peripheral edge of the plate, the effect of preventing reverse warpage generated in the plate-like body is great, and the rigidity imparting effect of the plate polymer is also great. On the other hand, when the taper angle exceeds 2.0 degrees, it is necessary to press the plate-like body with an overload when fixing the plate-like body using a holding jig during welding. For this reason, defective fixing is likely to occur, and residual stress due to incompatible deformation is likely to occur.

  The inner peripheral edge of the plate has a short peripheral length, and it is considered that there is little distortion around the inner peripheral edge of the plate, and only prevention of reverse warping should be considered. Therefore, reverse warping can be effectively prevented by setting the taper angle of the plate-like body to 1.0 ° or less, and the rigidity of the plate polymer can be increased by giving the taper angle to the plate-like body. If the reverse warp does not occur, the taper angle may be zero degrees. However, in order to reliably prevent the reverse warp, the taper angle is preferably set to 0.1 to 1.0 degree. On the other hand, when the taper angle of the plate-like body exceeds 1.0 degree at the inner peripheral edge of the plate, the same problem as the outer peripheral edge of the plate occurs.

  In the apparatus of the present invention, the plate radial width of the plate-like body is 2 mm or more at the outer periphery of the plate, and the dimensional ratio of the plate radial width to the plate diameter (plate radial width / plate diameter) is 0.004 to 0. .009. By setting the width in the radial direction of the plate to 2 mm or more and the dimensional ratio ≧ 0.004, the plate body can be provided with the strength and fixing performance necessary for fixing the outer periphery of the plate, and the rigidity of the plate polymer can be increased. Can be increased. On the other hand, in terms of the fixing strength and fixing performance of the outer periphery of the plate, it is not necessary to set the dimensional ratio> 0.009. Conversely, if it exceeds 0.009, the formation area of the corrugated irregularities formed between the plates is small. As a result, the heat transfer performance between fluids decreases.

  In the apparatus of the present invention, the plate outer peripheral edge and the end of the plate inner peripheral edge of the plate may be fixed by plasma arc welding. Plasma arc welding has higher arc directivity than TIG welding and the like, and the arc can be concentrated at a pinpoint. Therefore, since the bead width is narrow and the heat concentration is good, welding failure does not occur and high-speed welding is possible. Further, there is an advantage that welding distortion is small. Since the plate polymer has a large number of welding points, plasma arc welding is used and high-speed welding is possible, which has the advantage that the manufacturing period of the plate polymer can be shortened.

  Further, since the plate is forged into a complicated shape, distortion occurs. Therefore, it is possible to eliminate the accumulation of strain by adopting plasma arc welding with less generation of welding strain. Furthermore, since plasma arc welding has a smaller amount of heat input than TIG welding or the like, there is an advantage that generation of thermal strain and thermal stress of the base material, alteration and deterioration can be reduced.

In the apparatus of the present invention, the first fluid is a liquid, the first fluid is stored in the internal space of the hollow container, and the lower part of the plate polymer is disposed so as to be immersed in the first fluid. A spray nozzle for spraying at least a part of the first fluid toward the plate polymer may be disposed above the plate polymer. By providing this spray nozzle, the heat transfer performance between the first fluid and the second fluid can be enhanced.
Thereby, the filling amount of the first fluid into the hollow container can be reduced. Further, in the device of the present invention, since the taper angle is given to the outer peripheral edge of the plate, it becomes easy to form the wet surface of the first fluid on the plate surface, thereby further improving the heat transfer performance.

In the apparatus of the present invention, the first fluid is a refrigerant liquid, and a compressor, a condenser, a pressure reducing device, and an evaporator are interposed in the refrigerant circulation path, and the full liquid evaporator is installed in the refrigeration apparatus constituting the refrigeration cycle. It is good to be incorporated as. Since the shell-and-plate heat exchanger of the present invention can improve the heat transfer performance, the COP of the refrigeration apparatus can be improved if it is used as a full liquid evaporator in the refrigeration apparatus constituting the refrigeration cycle.
Further, since the full-liquid evaporator sends the saturated refrigerant gas to the compressor, the superheat degree adjustment of the refrigerant on the evaporator outlet side is not required. Therefore, it is not necessary to provide an automatic expansion valve such as a temperature expansion valve, and the equipment cost can be reduced.

In the refrigeration apparatus, the refrigerant liquid may be NH ₃ . NH ₃ has a specific heat ratio κ (= c _p / c _v ) of 1.31, which is larger than that of other refrigerants. Therefore, when heated, the NH ₃ expands and the circulation weight per unit volume decreases. Therefore, the cooling performance is reduced. However, in a refrigeration apparatus equipped with a full liquid evaporator, NH ₃ is not overheated on the outlet side of the full liquid evaporator, so that NH ₃ does not deteriorate. Further, if the apparatus of the present invention is used, even if the circulation amount of NH ₃ is reduced, the heat transfer performance can be maintained high, so that the influence of a decrease in the circulation amount of NH ₃ can be suppressed.

  According to the apparatus of the present invention, a hollow container and a plate polymer disposed inside the hollow container and overlaid with a large number of plates having flow path forming irregularities on the front and back surfaces, the same part of each plate A flow path penetrating the plate polymer is formed by the holes drilled in the plate, and the outer periphery of the plate and the inner periphery of the plate forming the hole are selectively joined between the plates and communicated with the internal space of the hollow container. A first fluid passage and a second fluid passage which is closed with respect to the internal space and communicates with the through-flow passage are alternately formed between the plates, and the first fluid passage is formed from the internal space of the hollow container. A shell-and-plate heat exchanger in which heat exchange is performed between the first fluid passing through the second fluid passage and the second fluid passing through the second fluid passage from the through flow path through the plate. The inner periphery is The plate-shaped body that is composed of a flat annular plate body integrated with the portion where the unevenness for forming the flow path is formed, is formed on the adjacent plate and is opposed to each other, toward the end side. It is formed to have tapered surfaces that are inclined in the direction of approaching each other, and the end sides of the plate-like body are fixed to each other, so that the end sides are reliably welded and pressed together when the end sides are fixed. Thus, distortion and residual stress generated during press forming of the plate can be suppressed, and reverse warping of the plate-like body can be eliminated. Therefore, it is possible to always fix the end portions of the plate-like body without any problem, and it is possible to increase the rigidity of the plate polymer by giving the plate-like body a taper angle.

It is front sectional drawing of the shell and plate type heat exchanger which concerns on one Embodiment of this invention apparatus. It is a side view sectional view of the shell and plate type heat exchanger. It is sectional drawing which shows the plate outer periphery of the said shell and plate type heat exchanger. It is sectional drawing which shows the plate inner periphery of the said shell and plate type heat exchanger. It is explanatory drawing which shows the welding procedure of a plate outer periphery or a plate inner periphery. It is explanatory drawing which shows the state which the reverse warp generate | occur | produced at the welding end of the plate. It is explanatory drawing which shows the case where the taper angle of a plate outer periphery or a plate inner periphery is excessive. It is a diagram which shows the experimental data of the plate outer periphery of the said shell and plate type heat exchanger. It is a diagram which shows the experimental data of the plate inner periphery of the said shell and plate type heat exchanger. It is a diagram which shows another experimental data of the said shell and plate type heat exchanger. It is a diagram which shows another experimental data of the said shell and plate type heat exchanger. It is sectional drawing which shows the example of 1 structure of the conventional shell and plate type heat exchanger. It is explanatory drawing which shows the manufacture procedure of a plate polymer.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

One embodiment in which the device of the present invention is applied to a CO ₂ liquefier of an NH ₃ / CO ₂ refrigerating apparatus will be described with reference to FIGS. First, the configuration of the CO ₂ liquefier 10 according to the present embodiment will be described with reference to FIGS. 1 and 2. The CO ₂ liquefier 10 is incorporated as a full liquid evaporator (cascade condenser) in the NH ₃ / CO ₂ refrigeration apparatus. In the CO ₂ liquefier 10, NH ₃ as a primary refrigerant and CO _{2 as a} secondary refrigerant are heat-exchanged, and NH ₃ absorbs heat and evaporates, while CO ₂ is liquefied.

1 and 2, a plate polymer 14 is accommodated in a hollow container 12 having a cylindrical shape. The plate polymer 14 is formed in a cylindrical shape by superposing a large number of disk-like plates 16. An inlet pipe 18 into which the NH ₃ refrigerant liquid flows is provided at the bottom of the hollow container 12, and an outlet pipe 20 through which the vaporized NH ₃ refrigerant gas flows out is provided at the top of the hollow container 12.

  Like the plate 130 shown in FIG. 13, the external shape of the plate 16 is circular, and linear unevenness | corrugation which has a waveform cross section is formed in parallel. The plate 16 has holes 22 and 24 in the vicinity of the outer peripheral edge 16a and at a position 180 degrees out of phase with the center point. The outer peripheral edge 16a of each plate 16 and the inner peripheral edges 22a and 24a of the holes 22 and 24 are formed in a flat annular plate-like body, and corrugated irregularities 16b are formed in the areas excluding these. The plate polymer 14 is configured by polymerizing a large number of such plates 16.

Since holes 22 and 24 are formed in the same part of each plate 16 and inner peripheral edges 22a and 24a of these holes are joined to each other, a flow path 26 is provided in the plate polymer 14 in a direction penetrating the plate polymer 14. And 28 are formed. In the side wall of the hollow container 12, an inlet pipe 30 into which CO ₂ refrigerant flows is provided at a position opposite to the hole 22, and the inlet pipe 30 passes through the side wall of the hollow container 12 and is directly connected to the through channel 26. Has been. Further, an outlet pipe 32 through which the CO ₂ refrigerant liquid flows out is provided at a position opposite to the hole 24, and the outlet pipe 32 passes through the partition wall of the hollow container 12 and is connected to the through-flow passage 28. The plate polymer 14 is fixed inside the hollow container 14 by a support (not shown).

  Similar to the plate polymer 142 in FIG. 13, between each plate 16, the passage opened to the internal space s <b> 1 of the hollow container 12, and the inlet pipe 30 through the through flow passages 26 and 28 to the outlet pipe 32, The passages closed with respect to the internal space s1 are alternately formed.

In the upper region of the internal space s1 of the hollow container 14, a nozzle tube 36 is disposed in the longitudinal direction of the hollow container 12, and a plurality of nozzle ports 38 that are disposed in the longitudinal direction and open downward in the lower portion of the nozzle tube 36. Is drilled. An NH ₃ refrigerant liquid pipe 42 is connected to the pipe line 40 through which the nozzle port 38 is led out of the hollow container 12. Further, an NH ₃ refrigerant liquid pipe 44 connecting the inlet pipe 18 and the NH ₃ refrigerant liquid pipe 42 is provided.

In such a configuration, the NH ₃ refrigerant liquid exiting from the condenser of the NH ₃ / CO ₂ refrigeration apparatus (not shown) is supplied to the nozzle pipe 36 via the NH ₃ refrigerant liquid pipe 42 and the conduit 40. In the case of a refrigeration apparatus in which an intermediate cooler or an economizer cooler is provided in the NH ₃ refrigerant circulation path downstream of the condenser, the NH ₃ refrigerant liquid discharged from these coolers is converted into an NH ₃ refrigerant liquid pipe. It is supplied to the nozzle tube 36 through 42. The NH ₃ refrigerant liquid is temporarily supplied to the internal space s1 of the hollow container 12 through the NH ₃ refrigerant liquid pipe 44, and the NH ₃ refrigerant liquid N stored in the lower region of the internal space s1 is supplied to the NH ₃ refrigerant liquid pipe 44. And 42 may be circulated to the nozzle tube 36. The NH ₃ refrigerant liquid supplied to the nozzle tube 36 is sprayed onto the plate polymer 14 from the nozzle port 38.

The NH ₃ refrigerant liquid sprayed on the plate polymer 14 from the nozzle port 38 passes through a passage between the plates 16 opened to the internal space s1. On the other hand, the CO ₂ refrigerant flows into the through channel 26 from the inlet pipe 30, passes through the passage between the plates 16 closed with respect to the internal space s 1, and flows out from the outlet pipe 32 through the through channel 28. The NH ₃ refrigerant liquid and the CO ₂ refrigerant exchange heat with each other via the plate 16, and the NH ₃ refrigerant liquid absorbs heat and vaporizes, and flows out from the outlet pipe 20. On the other hand, the CO ₂ refrigerant liquefies and flows out from the outlet pipe 32.

  Next, the configuration of the plate polymer 14 will be described with reference to FIGS. 3 and 4. FIG. 3 shows the outer peripheral edge 16a of the plate 16 whose tips are welded together. The outer peripheral edge 16a forms a flat annular plate that is integral with the corrugated irregularities 16b. The plate-like body forms tapered surfaces 46 that approach each other toward the outside of the plate. The taper surface 46 has a taper angle α with respect to a surface h parallel to the plate surface.

  FIG. 4 shows the inner peripheral edge 22a or 24a of the plate 16 whose tips are joined together. The inner peripheral edge 22a or 24a forms a flat annular plate body integrated with the corrugated irregularities 16b, and forms a tapered surface 48 that approaches each other toward the hole 22 or 24 side. The tapered surface 48 has a taper angle β with respect to a surface h parallel to the plate surface.

  In FIG. 5, the welding procedure of the outer periphery 16a or the inner periphery 22a, 24a is shown. In FIG. 5, the outer peripheral edge 16a or the inner peripheral edges 22a, 24a to be joined to each other are sandwiched and pressed by plate pressing jigs 50, 50 from both sides. And the edge part w of a plate-shaped object is welded by plasma arc welding in the state which contacted and fixed taper surfaces 46 and 46 or taper surfaces 48 and 48.

  Plasma arc welding has higher arc directivity than TIG welding and the like, and the arc can be concentrated at a pinpoint. Therefore, since the bead width is narrow and the heat concentration is good, there is no welding failure, high-speed welding is possible, and welding with less distortion is possible. Since the plate polymer 14 has a large number of welding locations, plasma arc welding is used and high-speed welding is possible, which has the advantage that the manufacturing period of the plate polymer 14 can be shortened.

  Further, since the plate 16 is forged into a complicated shape, distortion is likely to occur. Therefore, there is an advantage that distortion can be reduced by adopting plasma arc welding in which welding distortion hardly occurs. Furthermore, since plasma arc welding has a smaller amount of heat input than TIG welding or the like, there is an advantage that generation of thermal strain and thermal stress of the base material, alteration and deterioration can be reduced.

Conventionally, as shown in FIG. 6, the plate 16 sometimes has a reverse warp 52 in the plate-like body due to distortion, springback, or the like that occurs after press molding, and a gap may be generated between the plate-like bodies. In the plasma arc welding, since the arc is concentrated at a pin point, if the reverse warp 52 occurs, heat input to the material by the arc becomes unstable, and a welding failure is likely to occur.
In the present embodiment, the outer peripheral edge 16a or the inner peripheral edge 22a, 24a of the plate is a tapered surface 46 or 48, and during welding, the plate pressing jigs 50, 50 are pressed from both sides so that the ends w come into contact with and press each other. Therefore, the reverse warp 52 can be eliminated.

  That is, at the plate outer peripheral edge 16a, the plate body has a taper angle α of 1.5 degrees or more to ensure contact between the plate-like body end portions w of the outer peripheral edge 16a and to prevent the reverse warp 52 reliably. it can. Thereby, welding defects can be eliminated. Further, by forming the tapered surface 46, the rigidity of the plate polymer 14 can be increased as compared with the parallel surface.

  As shown in FIG. 7, when the taper angle α exceeds 2.0 degrees, it is necessary to press the plate-like body in advance with an overload by the plate pressing jigs 50 and 50 during welding. At this time, the pressing and fixing of the plate-like body becomes defective, which may result in poor adhesion or residual stress due to incompatible deformation. Therefore, the taper angle α is preferably set to 1.5 to 2.0 degrees.

  In addition, a plate radial direction width W of the tapered surface 46 is secured at least 2 mm, and a dimension ratio P of the plate radial direction width W to the plate surface diameter (plate radial direction width W / plate diameter) is P = 0.004-0. .009 is set. By setting the plate radial direction width W to 2 mm or more and P ≧ 0.004, the strength necessary for welding the plate outer peripheral edge 16a and good adhesion by welding can be provided, and the plate polymer 14 Stiffness can be increased. On the other hand, in terms of the strength of the outer peripheral edge 16a, it is not necessary to set P> 0.009. Conversely, if P> 0.009, the region of the refrigerant passage formed between the plates becomes small, so The heat transfer performance of is reduced.

  The inner peripheral edges 22a and 24a of the plate 16 have a short peripheral length, and there is little distortion after forming the plate. Therefore, by setting the taper angle β of the tapered surface 48 to 1.0 ° or less, the reverse warp 52 during welding can be eliminated. If the reverse warp 52 does not occur, the taper angle β = 0 may be used. However, considering the distortion after plate forming, the taper angle β is preferably set to 0.1 or more in order to eliminate the reverse warp 52 with certainty. Further, when the taper angle β exceeds 1,0 degrees, the above-described problems occur as in the outer peripheral edge 16a. Therefore, it is preferable that the taper angle β ≦ 1.0.

Further, in the present embodiment, the hollow container 12 in the interior space s1, since so as to jetted from the nozzle orifice 38 the NH ₃ refrigerant liquid to the plate polymer 14, the NH ₃ refrigerant liquid N of the hollow vessel 12 The heat exchange efficiency between the NH ₃ refrigerant liquid and the CO ₂ refrigerant can be improved by the method of only storing in the internal space s1. Further, in this embodiment, since the tapered surface 46 is formed on the outer peripheral edge 16a of the plate 16, it is easier to form a wet surface of the NH ₃ refrigerant liquid on the plate 16 than in the case of a parallel surface, and the adhesion time is reduced. Can be extended. Therefore, the heat exchange efficiency between the NH ₃ refrigerant liquid and the CO ₂ refrigerant can be further improved.

In the present embodiment, NH ₃ is used as a primary refrigerant, and the CO ₂ liquefier 10 is a full liquid evaporator. The full-liquid evaporator does not require adjustment of the superheat degree of the refrigerant on the outlet side of the evaporator because the saturated refrigerant gas is sent to the compressor. Therefore, it is not necessary to provide an automatic expansion valve such as a temperature expansion valve, and the equipment cost can be reduced.

NH ₃ has a specific heat ratio κ (= c _p / c _v ) of 1.31, which is larger than that of other refrigerants. Therefore, when NH ₃ is overheated, it expands, the circulation weight per unit volume decreases, and the cooling performance decreases. In this embodiment, since the CO ₂ liquefier 10 is a full liquid type, NH ₃ is not overheated. Therefore, the NH ₃ refrigerant does not deteriorate. Further, as described above, even if the circulation weight of the NH ₃ refrigerant is reduced, the heat transfer performance can be maintained high, so that the influence of the reduction in the circulation amount of the NH ₃ refrigerant can be suppressed.

Example 1
The plate 16 is made of stainless steel (SUS316L), the diameter of the plate 16 is 500 mm, the diameter of the through-flow passages 26 and 28 is 100 mm, and the thickness is 0.8 mm. The results of measuring the incidence are shown in FIGS. FIG. 8 shows the measurement result of the outer periphery of the plate, and FIG. 9 shows the measurement detection result of the inner periphery of the plate.

  In FIGS. 8 and 9, the curve A indicates the reverse warp occurrence rate, and the curve B indicates the welding failure occurrence rate. In FIG. 8, when the taper angle α is 1.8 degrees or less, the reverse warpage occurrence rate and the welding failure occurrence rate decrease as the taper angle α increases, but when the taper angle α is 1.8 degrees or more, the welding is reduced. The defect rate is starting to increase. The reason for this is considered to be that when the taper angle α is large, a defect occurs in fixing the plate-like body by the plate pressing jig 50 during welding, which leads to an increase in the incidence of welding defects. From FIG. 8, it can be seen that when the taper angle α is 1.5 to 2.0 degrees, the welding failure occurrence rate can be reduced most.

  FIG. 9 shows the same tendency as FIG. That is, when the taper angle β is 0.6 degrees or less, the reverse warpage occurrence rate and the weld failure occurrence rate decrease as the taper angle β increases, but when the taper angle β is 0.6 degrees or more, welding failure occurs. The rate is starting to increase. The reason is considered to be substantially the same as the case of the outer periphery of the plate. From FIG. 9, it can be seen that when the taper angle β = 0.1 to 1.0 °, the welding failure occurrence rate can be reduced most.

(Example 2)
FIG. 10 shows the relationship between the value of the dimension ratio P (plate radial direction width W / plate diameter D) and the rigidity of the plate polymer 14 manufactured using this plate using the same plate as in Example 1. It is a diagram which shows the result. In this experimental data, the filling amount of NH ₃ refrigerant liquid is 60 kg, PN (compatible oil) is used as the lubricating oil, the evaporation temperature is −12 to −13 ° C., the condensation temperature is 33 to 35 ° C., and the continuous 30 The average value of the minute operation is obtained.

As shown in FIG. 3, the rigidity was obtained by applying a load F from both sides of the pair plate and using the value of the force F measured when the corrugated ridges m contact each other as an index of rigidity.
FIG. 10 shows that the rigidity and heat transfer performance of the plate polymer 14 are both excellent when the dimensional ratio P = 0.004 to 0.009.

(Example 3)
FIG. 11 shows the result of measuring the amount of heat transfer in the full liquid CO ₂ liquefier of the NH ₃ / CO ₂ refrigeration apparatus. In FIG. 11, a straight line C is a case where the lower liquid supply and the upper spraying of the NH ₃ refrigerant liquid are used together as in the present embodiment, and the straight line D shows a case where only the lower liquid supply is used.
From the figure, the difference in the required refrigerant charge weight when the heat transfer performance is the same is obtained. For example, when the heat transfer amount K value is a certain amount K ₁ (w / m ² k), the required refrigerant filling weight is 57 kg when the upper spraying is used together and 60 kg when only the lower liquid supply is used. Therefore, as in this embodiment, in the case of combined use with upper spraying, the refrigerant charging weight can be reduced by 5%.
In FIG. 2, X indicates the refrigerant liquid level when the filling weight of the NH ₃ refrigerant liquid is 60 kg, and Y indicates the refrigerant liquid level when the filling weight is 50 kg.

  According to the present invention, it is possible to realize a shell-and-plate heat exchanger that eliminates poor welding and has increased rigidity, and is particularly suitable for application to an evaporator, a condenser, or the like of a refrigeration apparatus that constitutes a refrigeration cycle.

10, 100 CO ₂ liquefier 12, 102 Hollow container 14, 104, 142 Plate polymer 16, 106, 130 Plate 16a, 136 Plate outer peripheral edge 16b, 132 Corrugated irregularities 18, 30, 108, 116 Inlet tube 20, 32, 110, 118 Outlet pipe 22, 24, 112, 114, 134 Holes 22a, 24a, 138 Plate inner peripheral edge 26, 28 Through flow path 36 Nozzle pipe 38 Nozzle port 40 Pipe line 42, 44 NH ₃ refrigerant liquid pipe 46, 48 Taper Surface 50 Plate holding jig 52 Reverse warp 120 Separator 122 After cooler 140 Pair plate F Load N NH ₃ Refrigerant liquid P Size ratio X, Y NH ₃ Refrigerant liquid level W Tapered surface width a First heat exchange fluid b Second heat Exchange fluid m Mountain s Clearance w Plate body edge

Claims (5)

Inside the hollow container (12) having a cylindrical shape is provided with a plate polymer (14 ) in which a large number of plates having corrugated cross-sections formed in parallel on the front and back surfaces are superimposed,
Each plate (16) constituting the plate polymer (14) is in a position facing an adjacent plate, and each plate (16) includes a plate outer peripheral edge (16a) and the plate polymer (14). And the inner peripheral edge (22a, 24a) forming the outer peripheral edge (16a) and the hole (22, 24) are flat annular plates. The region excluding these is formed of a plate-like body on which corrugated irregularities (16b) are formed,
The plate-like body is formed so as to have tapered surfaces (46, 48) inclined in a direction approaching each other toward an end side of the outer peripheral edge of the plate and the inner peripheral edge (22a, 24a) of the plate. The plate outer peripheral edge of adjacent plates and the tapered surface end side w of the inner peripheral edge of the plate are fixed by plasma arc welding,
A nozzle tube (36) is arranged in the longitudinal direction of the hollow container (12) in the upper region of the hollow container above the plate polymer (14) in the internal space of the hollow container (12), and the nozzle tube (36) The second refrigerant is jetted toward the plate polymer from a number of nozzle ports (38) arranged in the longitudinal direction and opened downward in the lower part, and the nozzle port (38) is located outside the hollow container (12). The second refrigerant liquid pipe (42) is connected to the pipe line (40) led to, and the second refrigerant liquid circulates between the nozzle pipes (36).
On the other hand, a first channel (26) and a second channel (28) are formed in the direction penetrating the plate polymer (14 ) by the holes (22, 24) , and the first side wall of the hollow container The inlet pipe (30) into which the first refrigerant flows in a position opposite to the flow path (26), and the outlet pipe from which the first refrigerant liquid flows out to a position opposite to the second flow path (28). (32) A shell and plate type heat exchanger characterized by being provided. The shell-and-plate heat exchanger according to claim 1, wherein the outlet pipe (32) is configured to pass through a partition wall of the hollow container (12) and be connected to the second flow path (28). The taper angle of the tapered surface of the plate-shaped body at the outer peripheral edge of the plate is 1.5 to 2.0 degrees with respect to the plate surface, and the inner peripheral edges (22a, 24a) of the plate-shaped body are the taper angles of the tapered surface of the plate-shaped body. The shell and plate heat exchanger according to claim 1, wherein the angle is 1.0 degrees or less with respect to the plate surface.   The plate radial width of the plate-like body is 2 mm or more at the outer peripheral edge of the plate, and the dimensional ratio of the plate radial width to the plate diameter is 0.004 to 0.009. The shell-and-plate heat exchanger described. The first refrigerant is a CO2 refrigerant, while a compressor, a condenser, a decompression device, and an evaporator are interposed in a refrigerant circulation path of an NH3 refrigerant that functions as a second refrigerant, to form a refrigeration apparatus that constitutes a refrigeration cycle. The shell and plate heat exchanger according to claim 1, wherein the shell and plate heat exchanger is incorporated as a full liquid evaporator.

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