JP2001324284A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure pressure strength of a first tube 221 constituted of two sheets of planar material 221b, 221c. SOLUTION: A first tube 221 passing a first fluid and a second tube 222 passing a second fluid are jointed while being aligned in the longitudinal direction wherein the first tube 221 is constituted by sticking two sheets of planar material 221b, 221c while holding an inner fin 221a. End parts of the inner fin 221a are projected into tank parts 221d formed at the opposite ends of the first tube 221. Since a force at the tank part 221d inflating with the inner pressure is received at point D at the end part of joint face on the bending face of the tank part 221d, stress being applied to the planar materials 221b, 221c is lessened and pressure strength is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for exchanging heat between fluids flowing through tubes by joining two types of tubes formed of different materials. The present invention relates to a tube structure formed by laminating two plate members.

[0002]

2. Description of the Related Art In Japanese Patent Application Laid-Open No. Hei 5-196377, two flat tubes having a plurality of fluid passages therein are thermally joined to each other by means such as brazing or soldering over the entire area in the longitudinal direction. Thus, a heat exchanger has been proposed that transfers heat from a fluid (for example, a refrigerant) flowing in a plurality of fluid passages of one flat tube to a fluid (for example, water) flowing in a plurality of fluid passages of the other flat tube. ing.

[0003]

However, in the integrally extruded tube having a plurality of flow passages as described in the above publication, the area inside the flow passage section is reduced in order to secure the pressure resistance and improve the heat exchange efficiency. Is set to As a result, when water is used as the fluid, clogging is liable to occur due to precipitation of specific components, accumulation of corrosion products on the flow path partition walls, and the like, and the heat exchange capacity is reduced.

Accordingly, the present inventors have paid attention to the fact that the tube is formed of two plates instead of the extruded product as described in the above publication. However, when using a plate material, it is important to ensure the pressure resistance.

According to the research by the present inventors, for example, FIG.
As shown in (a), when a tank portion 221d is provided at the end of a tube 221 formed of two plate materials 221b and 221c, the tank portion 221d tries to expand by internal pressure, and the force is applied to both plate materials 221b and 221c. And inner fin 221
It has been found that stress is concentrated at point C, which is the end of the joining surface with a, and that there is a high possibility that cracks or the like will occur on the joining surface or the plate material and the pressure resistance will be reduced.

In addition to the above example, when the fluid passage is constituted by two plates, it is difficult to secure the pressure resistance unless a special structure is added.

[0007] The present invention has been made in view of the above points, and has as its object to provide a heat exchanger capable of ensuring the pressure resistance of a tube formed of two plates.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, the first tube (221) is provided.
Has a structure in which two plate members (221b, 221c) are bonded together, an inner fin (221a) is provided therein, and ends of the inner fin (221a) are formed at both ends of the first tube (221). Tank part (22
1d).

As a result, the force that causes the tank portion 221d to expand due to the internal pressure is received at the end of the joint surface of the bent portion with the tank portion 221d, and the plate members 221b and 221c are received.
Is reduced and the pressure resistance is improved.

According to the second aspect of the present invention, the two plate members (2
21b, 221c), the two plate members (221b, 221c) partially cut out at a portion (P) serving as an internal partition that divides the inside of the flow passage.
It is characterized in that a caulking portion (K) for fixing the space is provided and temporarily fixed.

As a result, the portion P serving as the internal partition is brought into a sufficiently close contact state by the temporary assembly, and a uniform brazing surface is provided to ensure pressure resistance. This can also prevent the occurrence of internal leak and ensure heat exchange capability.

[0012] According to a third aspect of the present invention, the first tube (221) is made of stainless steel or copper. Thereby, even when the heat exchanger uses water as the fluid, it is possible to ensure the corrosion resistance.

Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings.

In the present embodiment, the heat exchanger according to the present invention is applied to a household water heater, and FIG.
FIG. 2 is a schematic view of the water heater 100. FIG. In FIG. 2, reference numeral 200 (enclosed by a two-dot chain line) denotes a supercritical heat pump cycle (hereinafter, abbreviated as a heat pump) that heats hot water and generates hot water having a high temperature (about 85 ° C. in the present embodiment). .

The supercritical heat pump cycle is
A heat pump cycle in which the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure of the refrigerant, for example, a heat pump cycle using carbon dioxide, ethylene, ethane, nitrogen oxide, or the like as a refrigerant.

Reference numeral 300 denotes a plurality of heat retention tanks for keeping the hot water heated by the heat pump 200 warm and stored. Each of the heat retention tanks 300 is arranged in parallel with the flow of the hot water (hot water). ing.

In FIG. 2, reference numeral 210 denotes a compressor for sucking and compressing a refrigerant (carbon dioxide in this embodiment).
Reference numeral 10 denotes an electric compressor in which a compression mechanism (not shown) for sucking and compressing the refrigerant and an electric motor (not shown) for driving the compression mechanism are integrated.

Reference numeral 220 denotes a water heat exchanger (radiator) to which the heat exchanger according to the present embodiment is applied, which exchanges heat between the refrigerant discharged from the compressor 210 and hot water. FIG. 3 (a)
The plan view of the water heat exchanger in one embodiment of the present invention,
(B) is a side sectional view.

In the water heat exchanger 220, a first tube 221 through which hot water (water) flows and a plurality of second tubes 222 through which a refrigerant flows are brought into contact with each other so that the refrigerant flow and the hot water flow are opposed to each other. Is a counter-flow type heat exchanger.

Reference numeral 225 denotes a first header tank for distributing and supplying the refrigerant to the second tube 222.

Reference numeral 226 denotes a pipe material, and the first tube 2
A flow path is communicated from one side to the other of the two second tubes 222 arranged corresponding to the 21 reciprocating water passages.
Reference numeral 227 denotes a second header tank that collects and collects the refrigerant that has reciprocated in the second tube 222.

The first tube 221 and the second tube 222
Is formed flat. Then, the first tube 22
Reference numeral 1 denotes a brazed inner fin 221a and plate members 221b and 221c such that the inner fin 221a made of stainless steel and formed in a wavy shape is sandwiched between stainless steel plate members 221b and 221c.

The second tube 222 is made of aluminum and is formed by extrusion or drawing. By the way, both tubes 221 and 222 are
They are brazed so that their longitudinal directions coincide with each other.

By the way, in FIG. 2, 230 is the water heat exchanger 2
Reference numeral 240 denotes an electric expansion valve (decompressor) for reducing the pressure of the refrigerant flowing out of the refrigerant 20. An evaporator that absorbs the refrigerant and discharges the refrigerant toward an accumulator 250 (a suction side of the compressor 210) described later.

The reference numeral 250 designates a refrigerant which is separated from the refrigerant flowing out of the evaporator 240 into a gaseous refrigerant and a liquid refrigerant.
10 and the heat pump 200
It is an accumulator that stores excess refrigerant inside.

Reference numeral 260 denotes a blower (blowing amount adjusting means) which blows air (outside air) to the evaporator 240 and can adjust the blowing amount. The blower 260, the compressor 210 and the expansion valve 230 are described later. Is controlled by an electronic control unit (ECU) 270 based on the detection signals of the respective sensors.

Reference numeral 271 denotes a refrigerant temperature sensor (refrigerant temperature detecting means) for detecting the temperature of the refrigerant flowing out of the water heat exchanger 220, and 272 detects the temperature of hot water flowing into the water heat exchanger 220. It is a first hot water temperature sensor (first hot water temperature detecting means).

Reference numeral 273 denotes a refrigerant pressure sensor (refrigerant pressure detecting means) for detecting the pressure of the refrigerant flowing out of the water heat exchanger 220 (the refrigerant pressure on the high pressure side).
It is a second hot water temperature sensor (second hot water temperature detecting means) for detecting the temperature of hot water flowing out of the water heater 20. The detection signals of the sensors 271 to 274 are input to the ECU 270.

Here, the refrigerant pressure on the high pressure side refers to the compressor 2
10 refers to the pressure of the refrigerant present in the refrigerant passage from the discharge side of the expansion valve 230 to the inflow side of the expansion valve 230.
It is substantially equal to 0 discharge pressure (the internal pressure of the water heat exchanger 220). On the other hand, the refrigerant pressure on the low pressure side refers to the pressure of the refrigerant present in the refrigerant passage from the outlet side of the expansion valve 230 to the suction side of the compressor 210, and the pressure is the suction pressure of the compressor 210 (evaporator 240 Internal pressure).

Reference numeral 400 denotes an electric water pump (hereinafter, abbreviated as a pump) for supplying (circulating) hot water to the water heat exchanger 220 and adjusting the amount of hot water. This is a shut-off valve for preventing tap water supplied from a not-shown) from flowing into the water heat exchanger 220. The pump 400 and the shut-off valve 410 are also EC
It is controlled by U270.

Next, the water heat exchanger 220 according to the present embodiment
An outline of the manufacturing method of the present invention will be described.

First, the inner fin 2 is placed on the plate 221b.
The plate 21a and the plate 221c are set, and as shown in FIG. 4B, the nail N provided on the edge of the plate 221b is bent, and the end of the plate 221c is sandwiched and swaged. Further, as shown in FIG. 5, a crimping portion K provided at a portion P serving as an internal partition in a bonded portion of the two plate members 221b and 221c.
The first tube 221 is temporarily assembled (tube temporary assembling step). The caulking portion K has a burring portion set up on the plate member 221c, and when setting the plate member 221b,
The burring portion of the plate member 221c is expanded and crushed after fitting into the hole portion 1b, thereby performing the swaging. Also, when this temporary assembly is performed, the plate members 221b, 221c
A copper brazing material foil having a thickness of about 50 μm is inserted between the bonding surface and the inner fin 221a.

This is heated in a furnace for a predetermined time while applying a load by sandwiching it between two jigs, and they are integrally joined by brazing (copper brazing step).

Next, the first tube 221 brazed
On the second tube 222 and the header tanks 225, 2
After temporarily assembling parts such as 27 and the pipe member 226 sequentially, these parts are temporarily fixed by a temporary fixing jig such as a wire (heat exchanger temporary assembling step). At this time, the first tube 2
A thin aluminum brazing foil is inserted between 21 and the second tube 222.

Next, the heat exchanger 220 assembled in the temporary assembling step is heated for a predetermined time in a furnace by a Nocolok brazing method or a vacuum brazing method, and these are integrally joined (aluminum brazing step). .

In this embodiment, a foil is used as the brazing material. However, the brazing material may be coated (cladded) or coated or sprayed. In addition, aluminum and stainless steel may be joined using a high heat conductive adhesive.

Next, the features of this embodiment will be described.

FIG. 4B shows a cross section of the first tube 221 in one embodiment of the present invention. Inner fin 22
The end of 1a protrudes into the tank 221d.
As a result, the force that causes the tank portion 221d to expand due to the internal pressure is received at the point D at the end of the joint surface at the bent surface with the tank portion 221d, the stress applied to the plate members 221b and 221c is reduced, and the pressure resistance is reduced. improves.

Incidentally, the dimension d at which the end of the inner fin 221a protrudes into the tank portion 221d may be a dimension protruding from the end D of the joining surface even if various variations are taken into consideration.

As another feature of the present embodiment, the portion P serving as an internal partition is brought into a sufficiently close contact state by being caulked with a temporary assembly, and has a uniform brazing surface to secure pressure resistance. This can also prevent the occurrence of internal leak and ensure heat exchange capability.

(Other Embodiments) In the above embodiment, the present invention is applied to a water heat exchanger for exchanging heat between a refrigerant and hot water, but the heat exchanger according to the present invention is not limited to this. The present invention can also be applied to other heat exchangers such as a radiator for exchanging heat between water and air, a radiator for exchanging heat between refrigerant and air, and a gas cooler.

In the above embodiment, the plate member 221b,
221c is swaged, but the swaging type is not limited to this. Also, the bonded portion on the outer periphery may have the same caulking structure.

[Brief description of the drawings]

FIG. 1 is an external view of a water heater according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a water heater according to one embodiment of the present invention.

FIG. 3A is a plan view of a water heat exchanger according to an embodiment of the present invention, and FIG. 3B is a side sectional view.

FIGS. 4A and 4B show details of a portion A in FIG. 3B, wherein FIG. 4A is a cross-sectional view of a tube in an early stage of trial production, and FIG. 4B is a cross-sectional view of a tube according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of a tube according to an embodiment of the present invention, showing details of a BB cross section in FIG. 3A.

[Explanation of symbols]

 221 First tube 221a Inner fin 221b Plate (plate material) 221c Plate (plate material) 221d Tank part 222 Second tube P Internal partition part K Caulking part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Ken Yamamoto 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Inside Denso Corporation (72) Inventor Norihide Kawachi 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Inside Denso Corporation (72) Inventor Go Okinoya 1-1 1-1 Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Tomoaki Kobayakawa 1-1-3 Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Company (72) Inventor Kazutoshi Kusakari 1-1-3 Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Company (72) Inventor Michiyuki Saikawa 2-6-1 Nagasaka, Yokosuka City, Kanagawa Prefecture Yokosuka Research, Central Electricity Research Institute In-house F-term (reference) 3L036 AA01 AE34 3L103 AA11 BB42 CC02 CC28 DD10 DD32 DD33 DD42 DD70 DD82

Claims (3)

[Claims] A first tube (22) through which a first fluid flows.
1) and a second tube (222) formed of a different material from the first tube (221), through which the second fluid flows.
2) are joined so that their longitudinal directions coincide with each other, and further, the first tube (221) is formed by bonding two plate members (221b, 221c) to form a flow passage for the first fluid. And has an inner fin (221a) in the flow passage, and the inner fin (221a).
A heat exchanger characterized in that the end of (a) protrudes into tank portions (221d) formed at both ends of the first tube (221). 2. A first tube (22) through which a first fluid flows.
1) and a second tube (222) formed of a different material from the first tube (221), through which the second fluid flows.
2) are joined so that their longitudinal directions coincide with each other, and further, the first tube (221) is formed by bonding two plate members (221b, 221c) to form a flow passage for the first fluid. And the two plate members (221)
b, 221c), a caulking portion (K) for fixing between the two plate materials (221b, 221c) cut out at a portion (P) serving as an internal partition that divides the inside of the flow passage is provided. A heat exchanger characterized by being temporarily fixed. 3. The heat exchanger according to claim 2, wherein the first tube is made of stainless steel or copper.