JP2002350090A - Heat exchanger and method for fixing synthetic resin- made tube to heat-exchanger tube plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide (1) a heat exchanger, in which troubles of complicated works in fixing synthetic tubes to tube plates is eliminated, and cost is reduced, and further provide (2) a method of fixing the tubes thereto. SOLUTION: In the heat exchanger, a peripheral wall of an open end of the tube is clamped with the inside wall of a hole made in the tube plate and the outside peripheral surface of the hole of the hollow tubular part of a joint. In the method for fixing with a joint the tube in the hole made in a tube plate, the tube open-end is thrust through the hole in the tube plate to the other side. The hollow tubular part of the joint is thrust through the open end to the opposite side. The hollow tubular part of the joint is inserted in the hole of the tube. Thus, the synthetic resin-made tube is fixedly clamped with the inside wall of the hole and the outside peripheral surface of the hollow tubular part of the joint.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger and a method for fixing a synthetic resin tube to a tube plate of the heat exchanger. More specifically, a heat exchanger mainly used as a hot water supply device of a waste heat utilization system, and a step of fixing a synthetic resin tube to a tube plate of the heat exchanger, a fixing method that significantly reduces the number of parts About.

[0002]

2. Description of the Related Art Conventionally, in the field of handling a heat medium, a heat exchanger for exchanging heat between two kinds of mediums having different temperatures through partition walls has been used in order to effectively utilize heat. The heat exchangers used differ in the scale and structure of the apparatus and the type of the medium according to the application.For example, as relatively small heat exchangers, evaporators / condensers in various heat pump systems, floor heating systems And a radiator for cooling an engine of an automobile.

A typical example of the structure of the above heat exchanger is a shell and tube structure. The shell-and-tube heat exchanger is, for example, a heat exchanger 10 as shown in FIG. In this heat exchanger 10, a substantially rectangular parallelepiped shell 1 is provided.
1 (outer shell) is provided with one tube sheet 12 to form two narrow and wide closed spaces (11a, 11b). The tube sheet 12 has a U-shaped tube 14 on the side of the wide closed space 11a. (Heat transfer tubes) are connected and fixed in a large number, and the closed space 11 is narrow.
On the b side, a partition 16 is provided to separate the medium immediately before flowing into the tube 14 from the medium immediately after flowing out of the tube 14.

In the above heat exchanger 10, the shell 11
A medium that flows into the large closed space 11a and immerses the outside of the tube 14 (hereinafter, may be referred to as an “out-of-tube medium”) and a medium that passes through the inside of the tube 14 (hereinafter, referred to as
Heat exchange with the “medium in the tube”.

When the tube of the shell-and-tube heat exchanger is made of metal, the metal tube is often connected to the tube sheet by welding. There was a drawback that it gradually corroded when exposed. As an example of a technique for solving this drawback, a metal foil having a corrosion resistance is laminated on the inner wall surface of a metal tube, and a specially shaped tubular insert prepared from a metal material having a corrosion resistance is provided at the open end of the metal tube. A technique has been proposed in which the metal tube is inserted and fixed inside to prevent corrosion of the inner wall surface and the open end of the metal tube (Japanese Utility Model Laid-Open No. 58-128392).

According to the above proposed technique, the inner wall surface of the metal tube is protected by a corrosion-resistant metal foil, and the inside of the open end of the metal tube is protected by the tubular insert. The outer wall of
There is a disadvantage that the corrosive medium outside the tube corrodes over time. In addition, the steps of preparing the tubular insert and laminating the metal foil with a metal material having corrosion resistance are complicated and costly. Therefore, in order to solve these drawbacks, a shell-and-tube heat exchanger employing a synthetic resin tube instead of a metal tube has been proposed.

In the shell-and-tube type heat exchanger employing the above-mentioned synthetic resin tube, a metal joint is interposed between the tube sheet and the synthetic resin tube, and the synthetic resin tube is attached to the tube sheet. Often connected. FIG. 4 shows an example of the structure of the connection portion connected by this method.
As an example of a procedure until the structure shown in FIG. 4 is obtained, (1) a hole 13 is formed in the tube sheet 12, and (2) a hole 1 of this tube sheet is formed.
3 is provided with a female screw 13 ', (3) a sealing tape 50 is interposed between the male screw 41 of the metal joint 40, and (4) the male screw 41 of the metal joint 40 is inserted into the hole 13 of the tube sheet. Female screw 13 '
The metal joint 40 is screwed into the tube sheet 12
And (5) connecting and fixing the synthetic resin tube 14 to the metal joint 40 using the band 60 or the like.

However, according to the above-described method of connecting the synthetic resin tube to the tube plate of the heat exchanger, the connection operation is complicated since many steps are required, and especially the heat exchanger is small in size. In some cases, there is a drawback that the work becomes more difficult because a sufficient space for the work cannot be secured. In addition, there is also a disadvantage that the cost is increased because a large number of connecting parts such as a sealing tape and a band are required. Further, there is a disadvantage that the joint itself is corroded due to the pH in contact with the metal and the joint, and the service life is shortened.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present inventors have intensively studied to provide a heat exchanger which has solved the above-mentioned disadvantages and a method of fixing a synthetic resin tube to a tube plate of the heat exchanger. As a result, the present invention has been completed. The objects of the present invention are as follows. 1. To provide a heat exchanger in which the number of steps for fixing a synthetic resin tube to a tube sheet is greatly reduced, and the complexity of fixing work is largely eliminated. 2. To provide a heat exchanger that significantly reduces the number of parts required for fixing a synthetic resin tube to a tube sheet and greatly reduces costs. 3. A method of fixing a synthetic resin tube to a tube sheet of the heat exchanger. 4. To provide a heat exchanger with a long service life, in which the joint itself is not easily corroded.

[0010]

In order to solve the above-mentioned problems, according to the first invention of the present invention, a short hollow cylindrical shape having a flange at one end is provided in a plurality of holes formed in a tube sheet. In a heat exchanger in which a synthetic resin tube is fixed by a joint, the diameter of the tube plate hole is approximately equal to the outer diameter of the synthetic resin tube, and the outer diameter of the joint flange is the diameter of the tube sheet hole. The maximum diameter of the hollow cylindrical portion of the joint is slightly larger than the inner diameter of the synthetic resin tube, and the peripheral wall of the open end of the synthetic resin tube is formed between the inner wall of the hole in the tube sheet and the hollow cylindrical portion of the joint. A heat exchanger characterized by being sandwiched and fixed by an outer peripheral surface of a heat exchanger.

According to a second aspect of the present invention, a synthetic resin tube is provided by using a short hollow cylindrical joint having a flange at one end in a plurality of holes formed in a tube plate of a heat exchanger. In the method of fixing the diameter of the hole of the tube sheet is substantially equal to the outer diameter of the synthetic resin tube, the outer diameter of the flange of the joint is larger than the diameter of the hole of the tube sheet, the hollow cylindrical portion of the joint The maximum diameter is made slightly larger than the inner diameter of the synthetic resin tube, and the open end of the synthetic resin tube on one side of the tube sheet passes through the hole of the tube sheet and protrudes to the other side of the tube sheet. The hollow cylindrical portion of the above-described joint is fitted inside the open end of the resin tube, and the open end of the synthetic resin tube in a state where the joint is fitted is pushed into the hole of the tube sheet, thereby opening the open end of the synthetic resin tube. Between the inner wall of the hole in the tube sheet and the outer peripheral surface of the hollow cylindrical part of the joint. Characterized in that it provides a method of fixing the synthetic resin tube of the heat exchanger tube sheet.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The heat exchanger according to the first invention of the present invention is a so-called shell and tube heat exchanger having the above-described structure.
The size and shape of the shell that is the outer shell of the heat exchanger can be appropriately determined according to the type and flow rate of each of the above media, the place where the medium is installed, the application, and the like.
The shape may be a rectangular parallelepiped. One of the outer tube medium and the inner tube medium is a heated (or cooled) fluid and the other is a heated (or cooled) fluid, and heat exchange is performed between these media in the shell of the heat exchanger. To do.

Inside the heat exchanger, a tube sheet for separating the two kinds of mediums for heat exchange is fixed, and a tube made of a synthetic resin described later is fixed to this tube sheet. The number of the tube sheets is one or two. In the case of a single tube sheet, for example, the tube sheet can be arranged and fixed near one longitudinal end of the cylindrical shell at right angles to the longitudinal direction of the shell. In this case, the partition can be divided into two sections by a partition provided on the tube sheet, and one open end of the U-shaped synthetic resin tube is fixed to one section side of the tube sheet to fix the medium inlet in the tube. Then, the other open end of the U-shaped synthetic resin tube is fixed to the other partition side to serve as a medium outlet in the tube.

In the case where there are two tube sheets, for example, the tube sheets can be fixed to each other in the vicinity of both longitudinal ends of the shell at right angles to the longitudinal direction of the shell so as to face each other. In this case, one open end of the straight synthetic resin tube is fixed to one tube sheet to serve as a medium inlet in the tube, and the other open end of the synthetic resin tube is fixed to the other tube sheet. To be the medium outlet in the tube.

The tube sheet is made of a metal such as copper, copper alloy, aluminum, aluminum alloy, stainless steel, or glass fiber reinforced resin, and the thickness of the tube sheet is the same as that of the entire heat exchanger. It can be determined as appropriate according to the type and flow rate of the medium. The tube sheet is provided with a plurality of holes. The opening end of the synthetic resin tube is connected and fixed to the hole. The holes are formed as a pair of a hole for the medium in the tube and a hole for the medium in the tube. Therefore, as described above, when one tube sheet is used, holes having twice the number of synthetic resin tubes are perforated in this tube sheet. When two tube sheets are used, each tube is used. Drill the same number of holes in the plate as the number of synthetic resin tubes.

The diameter of the hole in the tube sheet is substantially equal to the outer diameter of the synthetic resin tube. The reason for this is that the open end of the synthetic resin tube passes through the hole of this tube sheet, projects to the opposite side of the tube sheet, and the hollow cylindrical portion of the joint is fitted into the open end of the synthetic resin tube. It is. In the present invention, “substantially equivalent” means a diameter that is the same as the outer diameter of the synthetic resin tube or a diameter that is approximately 5 to 30% larger than the outer diameter of the synthetic resin tube.

The joint has a short hollow cylindrical shape having a flange at one end, and is used for fixing a synthetic resin tube to a tube sheet. The outer diameter of the flange of the joint is made larger than the diameter of the hole in the tubesheet. When the hollow cylindrical portion of the joint is fitted inside the open end of the synthetic resin tube, the flange portion functions as a grip portion when the synthetic resin tube in which the joint is fitted is pushed into the hole of the tube sheet. Further, when the synthetic resin tube with the joint fitted therein is pushed into the hole of the tube sheet, the joint member does not come out of the hole of the tube sheet to the opposite side.

The hollow cylindrical portion of the joint is a portion fitted inside the open end of the synthetic resin tube. The outer peripheral surface of the hollow cylindrical portion can be a cylinder having no irregularities on the surface. In this case, the hollow cylindrical portion has a tapered shape whose outer diameter is gradually reduced from the vicinity of the distal end to the distal end or has the same diameter, so that the hollow cylindrical portion is easily fitted inside the open end of the synthetic resin tube. Is preferred. The maximum diameter of the hollow cylindrical portion is slightly larger than the outer diameter of the synthetic resin tube,
In particular, it is preferable that the diameter be 5 to 30% larger than the outer diameter of the synthetic resin tube.

It is preferable to provide at least one convex ring on the outer peripheral surface of the hollow cylindrical portion of the joint. This convex ring
The outer shape of the cross section when cut in the length direction so as to pass through the shaft center of the joint can be a trapezoidal shape that widens from the distal end side to the flange side of the hollow cylindrical portion of the joint. With such a trapezoidal shape, it becomes easy to fit the hollow cylindrical portion of the joint inside the open end of the synthetic resin tube, and after the fitting, the top of the trapezoidal convex ring is formed of the synthetic resin tube. The joint is difficult to come off because it gets into the inner wall surface. The number of the convex rings can be selected in the range of 1 to 4. The maximum diameter of this convex ring is 5 to 30% of the inner diameter of the synthetic resin tube.
Preferably, it is increased.

The synthetic resin tube is fixed to the tube sheet by the above-mentioned joint and functions as a heat transfer tube. The number of the synthetic resin tubes can be appropriately determined according to the size of the heat exchanger, the type of the medium to be heat-exchanged, the diameter, and the like. Generally, the area for heat exchange is increased. Examples of the synthetic resin constituting the synthetic resin tube include crosslinked polyethylene, polybutene, and polypropylene. The outer diameter and the inner diameter of the synthetic resin tube can be appropriately determined according to the size of the heat exchanger, the type of the synthetic resin, the type and flow rate of the medium passing through the tube, the number of the tubes, and the like.

Hereinafter, a method for fixing the synthetic resin tube to the tube sheet of the heat exchanger according to the second invention of the present invention will be described. First, the open end of the synthetic resin tube on one side of the tube sheet is passed through a hole in the tube sheet and protrudes to the other side of the tube sheet. Next, the hollow cylindrical portion of the joint is fitted inside the open end of the protruding synthetic resin tube. At this time, since the maximum diameter of the hollow cylindrical portion of the joint is slightly larger than the inner diameter of the synthetic resin tube, the inner wall surface of the synthetic resin tube is slightly expanded to the outside. Next, the open end of the synthetic resin tube in a state where the hollow cylindrical portion of the joint is fitted is pushed into the hole of the tube sheet, and the peripheral wall of the open end of the synthetic resin tube is
The tube is fixed between the inner wall surface of the hole of the tube sheet and the outer peripheral surface of the hollow cylindrical portion of the joint.

According to the method of the present invention, the synthetic resin tube is fixed to the tube plate of the heat exchanger because the hollow cylindrical portion of the joint is fitted into the open end of the synthetic resin tube that protrudes through the hole of the tube plate. In this state, by forcibly pushing the tube into the hole of the tube sheet, the wall surface of the synthetic resin tube is compressed and pinched between the inner wall surface of the hole of the tube sheet and the outer peripheral surface of the hollow cylindrical portion of the joint. Because it is In particular, when the above-mentioned convex ring is provided on the outer peripheral surface of the hollow cylindrical portion of the joint, the outer peripheral surface of the hollow cylindrical portion of the joint is made of synthetic resin because the top portion of the convex ring enters the inner wall surface of the synthetic resin tube. It is as described above that the joint is firmly locked to the inner wall surface of the tube and the joint is difficult to come off.

The heat exchanger according to the present invention can be used mainly in the hot water supply field. Specifically, it is used as a heater in a hot water supply system of an apartment house or a general house, a hot water supplier in a floor heating system, a warmer in a hot water system such as a hot spring, a hot water pool, and an aquarium for aquaculture. In addition, in this heat exchanger, warm wastewater generated by the time of operation of various factories and power plants can be used as a medium outside the tube.

【Example】

Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following description unless it departs from the gist.

FIG. 1 is a partially cutaway plan view of an example of a heat exchanger according to the present invention, and FIG. 2 is used for fixing a synthetic resin tube to a tube plate of the heat exchanger of FIG. It is a partially cutaway side view of an example of a joint. FIG. 3 is an example of a process diagram when a synthetic resin tube is fixed to a tube plate of a heat exchanger by the method of the present invention. FIG. 4 is a partially cutaway side view showing an example of a state in which a synthetic resin tube is fixed to a tube plate of a heat exchanger by a conventional fixing method.

FIG. 1 is a partially cutaway plan view of a heat exchanger 10 according to the first invention of the present invention. This heat exchanger 10
Is a so-called shell and tube heat exchanger,
The medium outside the tube is heated oil (heated fluid), and the medium in the tube is warm water (heated fluid) for floor heating. In this heat exchanger 10, one tube sheet 12 is fixed inside a substantially rectangular parallelepiped shell 11, and a hole 13
The two open ends of the U-shaped synthetic resin tube 14 are connected and connected to each other. The shell 11 includes a tube sheet 12
A large closed space 11a and a narrow closed space 11
b is formed, a support plate 15 for supporting the synthetic resin tube 14 is provided in the wide closed space 11a, and a partition 16 for separating hot water before heat exchange and hot water after heat exchange is provided in the narrow closed space 11b. Are provided.

In this heat exchanger 10, the hot water flowing from the medium inlet 17 in the tube passes through the synthetic resin tube 14 and is discharged from the medium outlet 17 ′ in the tube. The heated oil that has flowed into the large closed space 11a in the shell 11 is immersed in the outside of the synthetic resin tube 14 and then discharged from the tube outside medium outlet 18 '. At this time, the hot water is heated by the heat exchange with the heating oil, and at the same time, the temperature of the heating oil is lowered by the heat exchange with the hot water.

FIG. 2 is a partially cutaway side view of a joint 20 used for fixing the synthetic resin tube 14 to the tube sheet 12 of the heat exchanger 10. The joint 20 has a short hollow cylindrical shape provided with a flange portion 21 at one end, and three convex rings 23 are provided on the outer peripheral surface of the hollow cylindrical portion 22 of the joint 20. The convex ring 23 has a cross-section whose outer shape when cut in the longitudinal direction so as to pass through the axis of the hollow cylindrical portion 22 of the joint 20 has a divergent base extending from the distal end side of the hollow cylindrical portion 22 to the flange portion 21 side. It is shaped.

FIG. 3 shows a process chart when the synthetic resin tube 14 is fixed to the tube sheet 12 of the heat exchanger according to the method of the present invention. First, as shown in FIG.
2, a hole 13 having a diameter substantially equal to the outer diameter of the synthetic resin tube 14 is formed. Next, as shown in FIG.
One end of the synthetic resin tube 14 on one side of the tube sheet 12 projects through the hole 13 of the tube sheet to the other side of the tube sheet 12 and has a maximum diameter slightly larger than the inner diameter of the synthetic resin tube 14, Short hollow cylindrical joint 2 provided with flange 21 at one end
No. 0 hollow cylindrical portion 22 is fitted inside the synthetic resin tube 14. Next, as shown in FIG.
4 is pushed into the hole 13 of the tube sheet, and the peripheral wall of one end of the synthetic resin tube 14 is connected to the inner wall of the hole 13 of the tube sheet with the joint 2.
0 and is fixed between the outer peripheral surface of the hollow cylindrical portion 22.

[0030]

As described in detail above, the present invention has the following particularly advantageous effects, and its industrial value is extremely large. 1. In the heat exchanger according to the first aspect of the present invention, the peripheral wall of the synthetic resin tube is fixed by being sandwiched between the inner wall of the hole of the tube plate having the specific diameter and the outer peripheral surface of the hollow cylindrical portion of the joint having the specific shape. Therefore, the number of steps for fixing the synthetic resin tube to the tube sheet can be greatly reduced, and the complexity of the fixing operation can be greatly reduced. 2. In the heat exchanger according to the first aspect of the present invention, the peripheral wall of the synthetic resin tube is fixed by being sandwiched between the inner wall of the hole of the tube plate having the specific diameter and the outer peripheral surface of the hollow cylindrical portion of the joint having the specific shape. Therefore, the number of parts for fixing the synthetic resin tube to the tube sheet can be greatly reduced, and the cost can be greatly reduced. 3. In the heat exchanger according to the first aspect of the present invention, since the joint is not directly exposed to the medium outside the tube, the service life of the joint is not shortened even when the medium outside the tube is corrosive. 4. According to the method for fixing a synthetic resin tube to the tube plate of the heat exchanger according to the second invention of the present invention, the peripheral wall of the synthetic resin tube is joined to the inner wall of the hole of the tube plate having a specific diameter by a joint having a specific shape. Since it is sandwiched between the outer peripheral surface of the hollow cylindrical portion and fixed, the process of fixing the synthetic resin tube to the tube sheet can be greatly reduced, and therefore, the complexity of the fixing operation can be largely eliminated. . 5. According to the method for fixing a synthetic resin tube to a tube plate of a heat exchanger according to the second invention of the present invention, the peripheral wall of the synthetic resin tube is hollow with the inner wall of a hole of a tube plate having a specific diameter and a joint of a specific shape. Since it is fixed by sandwiching it with the outer peripheral surface of the cylindrical portion, the number of parts for fixing the synthetic resin tube to the tube sheet can be greatly reduced, and thus the cost can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a partially cutaway plan view of an example of a heat exchanger according to the present invention.

FIG. 2 is a partially cutaway side view of an example of a joint used for fixing a synthetic resin tube to a tube plate of the heat exchanger of FIG.

FIG. 3 is an example of a process diagram when a synthetic resin tube is fixed to a tube plate of a heat exchanger according to the method of the present invention.

FIG. 4 is a partially cutaway side view of an example of a state in which a synthetic resin tube is fixed to a tube plate of a heat exchanger by a conventional method.

[Explanation of symbols]

 10: Heat exchanger 11: Shell 11a: Wide closed space 11b: Narrow closed space 12: Tube plate 13: Hole in tube plate 13 ': Female screw 14: Tube made of synthetic resin 15: Support plate 16: Partition wall 17: Inside tube Medium inlet 17 ': Medium outlet inside tube 18: Medium inlet outside tube 18': Medium outlet outside tube 20: Metal joint 21: Flange 22: Hollow cylindrical part 23: Convex ring 40: Conventional metal joint 41: Male screw 50: Sealing tape 60: Band

Claims (4)

[Claims] 1. A heat exchanger comprising a synthetic resin tube fixed to a plurality of holes formed in a tube sheet by a short hollow cylindrical joint having a flange at one end. Diameter is almost equal to the outer diameter of the synthetic resin tube,
The outer diameter of the flange of the joint is made larger than the diameter of the hole in the tube sheet,
The maximum diameter of the hollow cylindrical portion of the joint is slightly larger than the inner diameter of the synthetic resin tube, and the peripheral wall of the open end of the synthetic resin tube is formed by the inner wall of the hole in the tube sheet and the outer peripheral surface of the hollow cylindrical portion of the joint. A heat exchanger characterized by being sandwiched and fixed. 2. The joint according to claim 1, wherein the maximum diameter of the hollow cylindrical portion is larger than the outer diameter of the synthetic resin tube by 5 to 30%.
The heat exchanger according to claim 1. 3. At least one convex ring is provided on the outer peripheral surface of the hollow cylindrical portion of the joint, and the maximum diameter of the convex ring is 5 to 30% larger than the inner diameter of the synthetic resin tube. The heat exchanger according to claim 1. 4. A method of fixing a synthetic resin tube to a plurality of holes formed in a tube plate of a heat exchanger using a short hollow cylindrical joint having a flange at one end. The diameter of the hole is approximately equal to the outer diameter of the synthetic resin tube, the outer diameter of the flange of the joint is larger than the diameter of the hole of the tube sheet, and the maximum diameter of the hollow cylindrical portion of the joint is the Slightly larger than the inner diameter, the opening end of the synthetic resin tube on one side of the tube sheet passes through the hole of the tube sheet and protrudes to the other side of the tube sheet. The hollow cylindrical portion of the joint is fitted inside, and the open end of the synthetic resin tube in a state where the joint is fitted is pushed into the hole of the tube sheet. Characterized by being sandwiched and fixed between the inner wall of the joint and the outer peripheral surface of the hollow cylindrical portion of the joint. How to fix a synthetic resin tube to the tube plate of the heat exchanger.