JP6442639B1 - Multi-coil heat exchanger - Google Patents

Abstract

A multi-coil heat exchanger that can perform uniform heat exchange between an outer peripheral side and an inner peripheral side in a shell and obtain high heat exchange efficiency as a whole.
A plurality of heat transfer tubes 4 wound in a coil shape in a shell 1 are arranged inside and outside, and each heat transfer tube 4 is connected to an inlet header 3A and an outlet header 3B at both ends. A multi-coil type that exchanges heat between the first fluid L1 that flows in a distributed manner from the header 3A to each heat transfer tube 4 and the second fluid L2 that flows from the inlet port 11 into the shell internal space 10 and travels toward the outlet port 12. In the heat exchanger, at least the outer layer side of the heat exchanging part 20 made of multiple coils has a plurality of coiled coil parts 2A to 2C in which a plurality of heat transfer tubes 4 are wound with the same winding diameter, and the heat exchanging part By reducing the number of coil turns of each heat transfer tube 4 from the inside to the outside of 20, the length of each heat transfer tube 4 is equalized in the entire heat exchange unit 20.
[Selection] Figure 1

Description

  The present invention relates to a multi-coil heat exchanger in which a plurality of heat transfer tubes wound in a coil shape in a shell are arranged inside and outside.

  2. Description of the Related Art Conventionally, a coil-type heat exchanger in which a heat transfer coil in which a heat transfer tube is wound in a coil shape is arranged in a cylindrical shell is known as one form of a shell-and-tube heat exchanger. In such a coil-type heat exchanger, generally, between the first fluid flowing in one direction of the shell as a whole through the tube of the heat transfer coil and the second fluid flowing in the opposite direction in the space in the shell. In order to increase the heat exchange efficiency, heat transfer areas for heat exchange are arranged by concentrically arranging two or more heat transfer coils with different winding diameters at the same winding pitch. Is used widely (for example, Patent Documents 1 to 4).

Japanese Patent Laid-Open No. 7-305976 Special table 2005-509125 gazette JP 2009-127971 A JP 2013-40706 A

  However, in the conventional coil type heat exchanger in which the heat transfer coils having the same winding pitch and different winding diameters are arranged concentrically in a double or triple layer, the length of the heat transfer tube due to the difference in the winding diameter is different. The outer heat transfer coil has a larger pressure loss than the inner heat transfer coil, and the flow rate of the first fluid is reduced accordingly. Therefore, the heat exchange between the outer peripheral side and the inner peripheral side in the shell becomes uneven. However, there is a problem that the overall heat exchange efficiency cannot be increased.

  In view of the above-described circumstances, the present invention provides an outer peripheral side and an inner peripheral side in a shell as a multiple coil type heat exchanger in which a plurality of heat transfer tubes wound in a coil shape in a shell are arranged in an inner and outer multiple. It is an object of the present invention to provide a heat exchanger that can perform uniform heat exchange and obtain high heat exchange efficiency as a whole.

If the means for achieving the above object is shown with reference numerals in the drawings, the invention of claim 1 is that a plurality of heat transfer tubes 4 wound in a coil shape in the shell 1 are arranged in an inner and outer multiple. Then, the heat transfer tubes 4 are connected to both the inlet header 3A and the outlet header 3B for the first fluid isolated from the inner space 10 at both ends, and are distributed to the heat transfer tubes 4 from the inlet header 3A. In the multi-coil heat exchanger that exchanges heat between the first fluid L1 and the second fluid L2 that flows into the shell inner space 10 from the introduction port 11 and travels toward the outlet port 12, the heat exchanging unit 20 formed of multiple coils. At least on the outer layer side, the plurality of wound coil portions 2A to 2C (heat transfer tube groups Z2, Z3) in which a plurality of heat transfer tubes 4 are wound with the same winding diameter are provided, and from the inside of the heat exchange portion 20 Each transmission towards the outside By reducing the number of coil turns of the heat tube 4, the length of each heat transfer tube 4 is equalized in the entire heat exchanging unit 20 ,
And the heat exchanging part 20 is divided into a plurality of inner and outer heat transfer tube groups Z1 to Z3, and the number of tube sections of each coil part in the inner heat transfer tube group is different from that of each coil part in the outer heat transfer tube group. As the number of tubes increases, the number of coil turns of the heat transfer tube 4 decreases from the inner coil portion to the outer coil portion in each of the heat transfer tube groups Z1 to Z3.

  According to a second aspect of the present invention, in the multi-coil heat exchanger of the first aspect, the interval between the heat transfer tubes 4 and 4 adjacent to each other in the heat exchanging portion 20 is set to be substantially equal to or less than the tube outer diameter. Yes.

  The invention of claim 3 is the multi-coil heat exchanger according to claim 1 or 2, wherein the heat exchange part 20 comprising the inner and outer triple coil parts 2A to 2C is provided in the long cylindrical shell 1. The number of windings of the heat transfer tube 4 is increased sequentially from the inner coil portion 2A to the outer coil portions 2B and 2C.

Next, effects of the present invention will be described with reference numerals in the drawings. First, according to the multiple-coil heat exchanger according to the first aspect of the present invention, a plurality of strips in which a plurality of heat transfer tubes 4 are wound at the same winding diameter on at least the outer layer side of the heat exchanging section 20 made of multiple coils. The number of coil turns of each heat transfer tube 4 from the inside to the outside of the heat exchanging portion 20 while having a wound coil portion (3 winding coil portion 2A, 4 winding coil portion 2B, 5 winding coil portion 2C). Since the length of each heat transfer tube 4 is equalized in the whole heat exchange part 5 by reducing, the pressure loss in each heat transfer tube 4 becomes uniform, and each heat transfer tube 4 is made into the heat exchange part 20 whole. In addition to equalizing the flow velocity and flow rate of the first fluid L1 passing therethrough, even if the number of turns of each heat transfer tube 4 decreases toward the outside of the heat exchanging portion 20, the tube arrangement density can be increased by multiple windings. , The entire heat exchanging unit 20 High heat exchange efficiency due to uniform heat exchange can be accomplished.
In particular, according to the present invention, particularly in a large-sized multiple coil heat exchanger in which the heat exchanging section 20 is 10 or more, the heat exchanging section 20 is divided into a plurality of heat transfer tube groups Z1 to Z3 inside and outside. The number of tube strips in each coil portion in the outer heat transfer tube group increases with respect to the number of tube strips in each coil portion in the heat transfer tube group, and the outside from the inner coil portion in each heat transfer tube group Z1 to Z3. Since the number of coil turns of the heat transfer tube is reduced toward the coil portion, the lengths of the multiple heat transfer tubes 4 constituting the heat exchanging portion 20 are equalized. Moreover, when the space | interval of the adjacent heat exchanger tubes 4 and 4 is substantially equal, the coil winding number of each heat exchanger tube 4 reduces toward the outer side from the inner side of the heat exchanger part 20, and the outer side of this heat exchanger part 20 is carried out. The coil width becomes narrower, but the outermost coil width in the inner heat transfer tube group is increased because the number of tubes in each coil portion in the outer heat transfer tube group increases with respect to the inner heat transfer tube group. On the other hand, the innermost coil portion width in the outer heat transfer tube group is widened, whereby a sufficient coil portion width can be secured for the heat exchange portion 20 as a whole, and high heat exchange efficiency can be obtained.

  According to the invention of claim 2, the interval between the heat transfer tubes 4 and 4 adjacent to each other in the heat exchange section 20 is set to be approximately equal to or less than the tube outer diameter and approximately equal to or less than the tube outer diameter. Since the tube arrangement density of 20 is equalized and the degree of contact of the second fluid L2 with respect to each heat transfer tube 4 is sufficiently increased, there is an advantage that uniform and high heat exchange is performed by the entire heat exchange section 20.

  According to invention of Claim 3, the heat exchange part 20 which consists of the coil parts 2A-2C of the inner and outer triple layers or more is provided in the long cylindrical shell 1, and the outer coil parts 2B, 2C from the inner coil part 2A. Since the number of windings of the heat transfer tube 4 increases sequentially, the number of heat transfer tubes in the entire heat exchanging unit 20 is relatively reduced, and the length of the inner and outer heat transfer tubes 4 is reduced. Can provide an equalized version.

It is a vertical side view of the coil type heat exchanger which concerns on 1st embodiment of this invention. It is a front view of the heat exchanger. It is a front view in the state where the header cover of the heat exchanger was removed. It is a vertical front view in the longitudinal direction intermediate part of the heat exchanger. It is a model longitudinal cross-sectional side view of the coil type heat exchanger which concerns on 2nd embodiment of this invention.

  Embodiments of a multi-coil heat exchanger according to the present invention will be specifically described below with reference to the drawings.

  As shown in FIGS. 1 to 4, in the multi-coil heat exchanger according to the first embodiment, three coil portions 2 </ b> A to 2 </ b> C having different winding diameters at the same winding pitch are concentric in a long cylindrical shell 1. The heat exchange part 20 is comprised by arrange | positioning. The shell 1 includes a body 1a made of a hard synthetic resin such as PVC (polyvinyl chloride) or stainless steel, and end plates 1b and 1b made of a hard synthetic resin such as PVC that seals the opening at both ends. In addition, an inlet header 3A for the first fluid L1 and an outlet 12 for the second fluid L2 are provided on one end side, and an outlet header 3B for the first fluid L1 and an outlet header for the second fluid L2 are provided on the other end side. A supply port 11 is provided. Further, L-shaped frame-shaped mounting legs 13 and 13 made of hard synthetic resin or stainless steel are fixed to the lower end of the outer periphery of the shell portion 1a of the shell 1 near both ends thereof.

  Both the inlet header 3A and the outlet header 3B for the first fluid L1 form a space isolated from the shell inner space 10 between the end plate 1b of the shell 1 and the header cover 31 bolted to the outer surface thereof. The header cover 31 is provided with a connection port 32 for external piping (not shown). A disc-shaped seal plate 7 made of a fluororesin such as PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) is interposed between the end plate 1b and the header cover 31. The header cover 31 has a liner 31b made of PTFE (polytetrafluoroethylene) or the like attached to the inner surface of a cover main body 31a made of a hard synthetic resin molded product such as PVC.

  The supply port 11 and the discharge port 12 for the second fluid communicate with the shell internal space 10 and are shown up and down for easy understanding in FIG. 1, but in actuality the shell 1 as shown in FIGS. Projected to the left and right of

  Each of the three coil portions 2A to 2C of the heat exchanging portion 20 is formed by winding a plurality of heat transfer tubes 4 made of a soft thermoplastic fluororesin such as PFA in a parallel spiral shape. The number is different. That is, the number of tubes is three for the inner coil portion 2A having a small winding diameter, four for the middle coil portion 2B, and five for the outer coil portion 2C having a large winding diameter. And all the heat-transfer tubes 4 of these coil parts 2A-2C are a thing of the same length. In FIG. 1, only one of the plurality of heat transfer tubes 4 constituting each of the coil portions 2 </ b> A to 2 </ b> C is hatched.

  As shown in FIGS. 1 and 4, each heat transfer tube 4 is passed through a number of tube insertion portions 6 a provided on both sides in the width direction of the belt-like support plate 6, thereby providing a constant winding pitch in the shell axis direction. And it is hold | maintained at the state wound by the parallel spiral shape with the winding diameter. The support plate 6 has a width substantially equal to the inner diameter of the shell 1, and a screw rod-like support shaft 61 is provided in the center in the width direction at both ends thereof, and the width direction without the tube insertion portion 6 a is provided. A plurality of (in this case, two) disk-shaped baffles 5 are fitted and fixed at a predetermined interval in the longitudinal direction of the shell at the center. In addition, the tube insertion portion 6a of the support plate 6 includes a rear circular cutout shape that opens outward in the outer row corresponding to the outer coil portion 2C, the inner row corresponding to the inner and middle coil portions 2A and 2B, and The middle row has a round hole shape. Thus, each support shaft 61 has a length substantially equal to the inner diameter of the shell 1, and the support plate 6 is sandwiched between the nut members 62 and 62 screwed from both sides. Further, the baffle 5 projects in a semicircular shape on both sides of the support plate 6. The support plate 6, the support shaft 61, the nut member 62, and the baffle 5 are made of a hard fluororesin molded product such as PTFE.

  The support plate 4 wound and held with the heat transfer tube 4 is loaded in the shell inner space 10 with the plate surface along the shell axis direction, and both side edges and both ends of the support shafts 61 are connected to the shell 1. By being in contact with or close to the inner periphery of the shell 1, the shell 1 is held in a state free from rattling. And each baffle 5 is arrange | positioned in the center part 10a surrounded by 2 A of inner coil parts in the space 10 in a shell.

  As shown in FIGS. 1 and 3, both end portions of each heat transfer tube 4 are inserted into the through-holes 14 connected to the end plate 1 b of the shell 1 and the seal plate 32, so that the inlet header 3 </ b> A and the outlet are provided. The peripheral edge slightly protruding into the header 3B is welded (welded and fixed) 4a to the seal plate 7 so as to communicate with the inlet header 3A and the outlet header 3B. As shown in FIG. 1, a tubular male connector 8 made of a thermoplastic fluororesin such as PFA is interposed in the insertion portion of the heat transfer tube 4 from the inside to each insertion portion 14 of the end plate 1b. Yes.

  In the multi-coil heat exchanger configured as described above, the first fluid L1 is introduced into the inlet header 3A, while the second fluid L2 is supplied to the supply port 11, whereby the first fluid L1 is transferred from the inlet header 3A to the coil portion 2A. In the course of passing through the heat transfer tubes 4 in a spiral manner, the heat is exchanged with the second fluid L2 flowing in the opposite direction in the shell inner space 10, and the outlet header. While joining at 3B and flowing out, the second fluid L2 that has passed through the in-shell space 10 is discharged from the discharge port 12 to the outside.

  In this multi-coil heat exchanger, the winding diameter of the heat transfer tube 4 increases toward the outer side such as the coil portion 2A <coil portion 2B <coil portion 2C, but the heat transfer tube 4 constituting these coil portions 2A to 2C Since all have the same length, the first fluid L1 passing through any of the heat transfer tubes 4 receives equal pressure loss and does not cause a difference in flow velocity, and thus the heat transfer tubes 4 perform uniform heat exchange. Further, the outer coil unit has a longer circumferential length due to the difference in winding diameter, but the number of heat transfer tubes is three in the inner coil portion 2A, four in the middle coil portion 2B, and five in the outer coil portion 2C. By increasing the number of the book and the outer side, the arrangement density of the heat transfer tubes 4 in the circumferential direction is also equalized from the inner side to the outer side, and the difference in heat exchange amount per unit area between the inner peripheral side and the outer peripheral side is less likely to occur. High heat exchange efficiency can be obtained in the entire exchange section.

  In the multiple coil heat exchanger of the first embodiment, the second fluid L2 flowing into the shell inner space 10 from the supply port 11 also fills the central portion 10a surrounded by the inner coil portion 2A. Since the central portion 10a has baffles 5 at a plurality of locations in the longitudinal direction of the shell, the second fluid filled in the central portion 10a does not go to the discharge port 12 as it is, and the coil portions 2A are adjacent to each baffle 5. Since ~ 2C is guided to the peripheral side where it is disposed and passes between the wound heat transfer tubes 4 group, high heat exchange efficiency can be ensured.

  In the multi-coil heat exchanger according to the first embodiment, each heat transfer tube 4 is wound in a parallel spiral shape through the tube insertion portion 6 a of the support plate 6, so that the coil portions 2 </ b> A to 2 </ b> C are within the shell 1. A stable winding state is maintained. Further, when the coil portions 2A to 2C are constructed, it is possible to easily set a constant winding diameter at the same winding pitch only by sequentially passing the heat transfer tubes 4 through the tube insertion portions 6a of the support plate 6. Furthermore, when the heat exchanger is assembled, the coil portions 2A to 2C can be disposed in the shell 1 simply by inserting the support plate 6 around which the heat transfer tube 4 is wound and held into the body portion 1a of the shell 1. Easy operation and high work efficiency.

  The multi-coil heat exchanger of the present invention has a coil portion of a plurality of windings in which a plurality of heat transfer tubes 4 are wound with the same winding diameter on at least the outer layer side of the heat exchanging portion 20 formed of a multi-coil, As long as the number of coil turns of each heat transfer tube 4 decreases from the inside to the outside of the heat exchange unit 20, the length of each heat transfer tube 4 may be equalized throughout the heat exchange unit 20, It includes not only those having triple coil portions 2A to 2C as in the embodiment, but also those having double or quadruple or more coil portions having different winding diameters.

  In a large multiple coil heat exchanger having a large number of internal and external coils such as 10 or more layers, the heat exchange unit 20 is composed of multiple coil units each having the same number of windings as in the second embodiment shown in FIG. It is divided into a plurality of inner and outer (three in the figure) heat transfer tube groups Z1 to Z3, and the number of windings of the outer heat transfer tube group is increased with respect to the number of windings of the inner heat transfer tube group, In the multiple coil portions of the heat transfer tube groups Z1 to Z3, by reducing the number of coil turns per tube of the outer coil portion with respect to the adjacent inner coil portion by about 1 to 2, heat transfer of the entire heat exchange portion 20 What is necessary is just to set it as the structure which equalized the length of the tube 4. FIG. In addition, about the innermost heat-transfer tube group Z1, you may form each coil part only with the one heat-transfer tube 4 (one roll). Thus, in each heat transfer tube group Z1 to Z3, the number of coil turns per tube of the outer coil portion is reduced with respect to the adjacent inner coil portion, with the tube interval of the coil portion being constant. As shown by the enclosed imaginary line, the vertical width is shorter toward the outside.

  The multi-coil heat exchanger of the second embodiment shown in FIG. 5 is intended for the case where the second fluid L2 is a liquid such as a high temperature liquid to be processed, and has a bottomed cylindrical shape with the shell 1 opened upward. The tank 1c and the cover plate 1d are provided with an overflow cylinder 15 standing in the center of the inside thereof, and an intermediate cylinder 16 concentrically surrounding the overflow cylinder 15 is disposed. 16 divides the inner space 10 into a central portion 10a and an outer annular portion 10b. A plurality of support plates 6 are attached in a radial arrangement on the outer periphery of the intermediate cylinder 16, and a large number of heat transfer tubes 4 are wound in multiple coils through tube insertion portions (not shown) provided on the support plates 6. And the heat exchange part 20 which consists of heat-transfer tube group Z1-Z3 is comprised by the annular part 10b. In addition, the inlet header 3A and the inlet header 3B of the first fluid L1 and the supply port 11 of the second fluid L2 are provided on the lid plate 1d, and the lower end of the overflow cylinder 15 is the drain at the center of the bottom of the tank body 1c. A liquid circulation part 10c that communicates with the outlet 12 and communicates the central part 10a of the inner space 10 and the annular part 10b between the lower edge of the intermediate cylinder 16 and the bottom of the tank body 1c. . Each heat transfer tube 4 is disposed below the heat exchange section 20 through a gap d formed between the inlet header 3A and the heat transfer tube groups Z1 and Z2 and between the heat transfer tube groups Z2 and Z3. The upper part of 20 is connected to the outlet header 3B.

  In the multi-coil heat exchanger of the second embodiment, the second fluid L2 (liquid to be treated) supplied from the supply port 11 is in the process of descending the annular portion 10b of the inner space 10 of the shell, After exchanging heat with the second fluid (usually cooling water) that flows upward in a spiral manner in the numerous heat transfer tubes 4, the fluid flows from the liquid circulation part 10 c to the central part 10 a and rises, 15 flows down to the outside and is discharged to the outside through the discharge port 12. However, since the lengths of the multiple heat transfer tubes 4 constituting the heat exchanging section 20 are equalized, the inside of each heat transfer tube 4 is The first fluid L1 that passes through is subjected to equal pressure loss and does not cause a difference in flow velocity, so that uniform heat exchange is performed in each heat transfer tube 4, so that high heat exchange efficiency is obtained as a whole. In addition, each of the heat transfer tube groups Z1 to Z3 is configured such that the number of coil turns of the heat transfer tube 4 of each coil portion decreases from the inner side toward the outer side, as indicated by the phantom line in the drawing, The coil portion width becomes narrower toward the outer side of 20, but the number of tubes in each coil portion in the outer heat transfer tube group increases with respect to the inner heat transfer tube group. With respect to the coil part width, the innermost coil part width in the outer heat transfer tube group is widened, whereby a sufficient coil part width can be secured for the heat exchange part 20 as a whole, and high heat exchange efficiency is obtained.

  The coil-type heat exchanger of the present invention can be modified in various ways other than those exemplified in the first and second embodiments with respect to the detailed configuration such as the form and arrangement position of each component and the coupling structure between members. On the other hand, there is no restriction | limiting about the kind of the 1st fluid L1 and the 2nd fluid L2 which are heat-exchanged, and a liquid and gas are included.

DESCRIPTION OF SYMBOLS 1 Shell 10 Shell inner space 11 Supply port for 2nd fluid 12 Discharge port for 2nd fluid 2A Inner coil part 2B Middle coil part 2C Outer coil part 20 Heat exchange part 3A Inlet header 3B Outlet header 4 Heat transfer Tube L1 1st fluid L2 2nd fluid Z1-Z3 Heat transfer tube group

Claims (3)

A plurality of heat transfer tubes wound in a coil shape in the shell are arranged inside and outside, and each heat transfer tube communicates at both ends to the inlet header and outlet header for the first fluid isolated from the space in the shell Multi-coil heat exchange that exchanges heat between the first fluid that is connected and flows distributed from the inlet header to each heat transfer tube and the second fluid that flows into the inner space of the shell from the inlet and heads toward the outlet. In the vessel
At least the outer layer side of the heat exchanging portion made of multiple coils has a plurality of wound coil portions in which a plurality of heat transfer tubes are wound with the same winding diameter, and each heat transfer from the inside to the outside of the heat exchanging portion By reducing the number of coil turns of the tube, the length of each heat transfer tube is equalized throughout the heat exchange section ,
And the said heat exchanging part is fractionated into a plurality of inner and outer heat transfer tube groups, and the number of tube strips of each coil part in the outer heat transfer tube group with respect to the number of tube sections of each coil portion in the inner heat transfer tube group And a multi-coil heat exchanger configured such that the number of coil turns of the heat transfer tube decreases from the inner coil portion to the outer coil portion in each heat transfer tube group .   The multi-coil heat exchanger according to claim 1, wherein intervals between adjacent heat transfer tubes having the same winding diameter in the heat exchange section are set to be approximately equal to or less than the tube outer diameter. A heat exchange part consisting of three or more inner and outer coil parts is provided in a long cylindrical shell, and the number of windings of the heat transfer tube is increased sequentially from the inner coil part to the outer coil part. The multi-coil heat exchanger according to claim 1 or 2.

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