JPH1068596A - Heat exchanger for water and aqueous solutions - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger for water and aqueous solutions which can facilitate a working, can cope with a heat cycle having a great temperature difference and can reduce a manufacturing cost. SOLUTION: In the heat exchanger, since a water tube 39 is made of copper or an iron alloy, the water tube 39 which works as a heat receiving body is stable against water and aqueous solutions. Since fins 43 are made of an iron alloy, the fins 43 have an excellent workability. Namely, protrusions and walls can be readily formed so that the heat exchanging characteristics can be enhanced. Furthermore, plating and a surface treatment are facilitated so that the durability of the heat exchanger is enhanced and the heat exchanger can withstand a heat cycle having a great temperature difference. Still furthermore, since they are made of the iron alloy, they are inexpensive and contributed to a reduction of manufacturing cost in the production of heat exchangers.

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 heat-exchanging water or an aqueous solution, and more particularly to a heat exchanger formed by inserting a water pipe for flowing water or an aqueous solution into a number of fins.

[0002]

2. Description of the Related Art A heat exchanger is generally known in which a pipe through which a fluid flows is inserted into a large number of fins.
In such a heat exchanger, it is common to flow gas or liquid as a heat-exchange medium in a tube and flow a gas or liquid fluid as a heat medium between the fins. In this type of heat exchanger, a tube and a fin are used. Uses a copper or aluminum material having excellent thermal conductivity.

For example, in a heat exchanger for flowing a refrigerant such as a cooler (air conditioner) or a refrigerator, an aluminum material is generally used for a tube and a fin through which the refrigerant flows, and water such as a water heater is used. Is heated using a copper water tube, and the fins are made of a copper material.

[0004]

However, copper or aluminum has the characteristics of low mechanical strength and high expansion coefficient. For this reason, when a fin using a copper or aluminum material is used for a heat cycle having a large temperature difference, there is a disadvantage that deformation and cracks are easily generated.

[0005] Copper and aluminum are also inferior in terms of workability. For example, in order to improve heat exchange characteristics with respect to fins using these materials, protrusions for forming flow paths and increase in surface area are provided. There is a problem that it is difficult to form protrusions and folds. That is, as shown in FIG. 8, in the conventional heat exchanger for a water heater, the fins 103 are flat with respect to the water pipe 101, or a slight cut end formed by punching out even if a projection is formed. Although the protrusion 105 can be easily formed, it is difficult to form a protrusion having a large surface area, and the degree of freedom in forming is small. Also,
Copper, which is a fin material, is inferior in surface stability and has a problem that it is difficult to perform surface treatment such as plating and painting.

Further, copper and aluminum are expensive and there is a problem that the manufacturing cost of the heat exchanger is high.

[0007] Therefore, an object of the present invention is to facilitate molding and adapt to a heat cycle having a large temperature difference.
Another object of the present invention is to provide a heat exchanger for water or an aqueous solution that can reduce costs.

[0008]

In order to achieve the above object, the invention according to claim 1 comprises a plurality of fins arranged with a gap therebetween, and a water pipe inserted into these fins and through which water or an aqueous solution flows. Wherein the water tube is made of a copper material or an iron alloy, and the fins are made of an iron alloy.

[0009] In this specification, the copper material means a material containing a copper alloy in addition to high-purity copper. In addition, the term “iron alloy” refers to a material containing steel or special steel in addition to high-purity iron.

According to the first aspect of the present invention, since the water pipe is made of a copper material or an iron alloy, it is stable against water or an aqueous solution as a heat exchange target, and is a water pipe for clean water. Can also be used. Further, since an iron alloy is used for the fins, the workability is good and the projections and folds can be easily formed, so that the heat exchange characteristics can be improved. Further, plating and surface treatment are easy, and the durability of the heat exchanger is improved, and the heat exchanger can be adapted to a heat cycle having a large temperature difference. In addition, since an iron alloy is used as the material of the fin, it is inexpensive, and the manufacturing cost for manufacturing the heat exchanger can be reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, the heat exchanger is a gas-liquid heat exchanger that passes a gas as a heat exchange medium between the fins. The fin has a large number of protrusions formed by overhangs or notches formed thereon.

According to the second aspect of the present invention, since the fin is formed with the protrusion due to the overhang or the protrusion due to the notch, the gas as the heat exchange medium passes through the fin when the heat exchange medium passes therethrough. The area can be increased and the flow path of the heat exchange medium can be efficiently formed.

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
In the invention described in (1), the iron alloy used for the fin is a steel material or a special steel material.

In the present specification, steel means iron containing 0.035 to 1.7% by weight of carbon (C) in iron, and nickel (Ni), manganese ( Mn), chromium (Cr) or the like as a component.

According to the third aspect of the present invention, by using a steel material or a special steel material as the iron alloy, it is possible to select a material according to environmental characteristics such as use in a heat cycle having a large temperature difference. it can.

The invention described in claim 4 is the first to third aspects of the present invention.
In the invention described in (1), water such as tap water or tap water is circulated through the water pipe, and a gas heated by a burner is passed between the fins to heat the water.

The invention according to claim 4 is used for supplying hot water or circulating tap water or circulating tap water to a water pipe or for heating a bath, and heating by a burner.
Even when the temperature difference in such a heat cycle is large, the fin is unlikely to be deformed or cracked. Generally, a steel material has about twice the mechanical strength as compared with a copper material, has an expansion rate of 2/3, and is excellent in heat resistance. In addition, the surface treatment can be easily performed when the surface such as plating is processed as required.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG.
An embodiment of the present invention will be described in detail with reference to FIG. The heat exchanger 1 according to the embodiment of the present invention will be described by taking as an example a case where the heat exchanger 1 is used for a gas water heater 3 for heating tap water with a gas.

As shown in FIG. 1, the gas water heater 3 generally comprises a water supply pipe 5 to which clean water is supplied, a heat exchanger 1 for introducing water from the water supply pipe 5 and exchanging heat, and a heat exchanger. 1 comprises a heating section 7 for blowing heated gas and a hot water supply pipe 9 for supplying hot water after heat exchange.

The water supply pipe 5 is connected to an inlet of a water pipe (described later) 17 of the heat exchanger 1 via a water filter 9, a water input thermistor 13, and a water quantity sensor 15. A hot water supply pipe 9 is connected to an outlet of the water pipe 17, and is connected to a pipe for supplying hot water to a washroom or a kitchen via a tapping thermistor 19, a water quantity thermistor 21, and a drain valve 23. still,
Reference numeral 24 denotes a bypass passage.

The heating section 7 is disposed below the heat exchanger 1 and includes a gas burner 25 for burning gas, a spark plug 27 for igniting the gas burner, and a combustion fan. The heating section 7 ignites the gas introduced from the gas pipe 29. Then, a high-temperature gas is supplied to the heat exchanger. The heating unit 7 includes an outside air thermistor 31, a gas solenoid valve 33, a gas proportional valve 35,
A source gas solenoid valve 37 is provided to adjust the combustion state by the gas.

Here, referring also to FIG. 2, the heat exchanger 1 is housed in a case 41, and a plurality of fins 43 arranged at intervals, and these fins 43 are fitted and inserted. And a water pipe 17.

The water pipe 17 surrounds the outside of the case 41 and is arranged in a meandering manner inside the case, thereby improving the heat exchange efficiency.

In this case 41, heated air heated by gas combustion is introduced from the bottom up, and after passing through a heat exchanger, the exhausted combustion gas is exhausted from an exhaust pipe 45. I have.

The water pipe 17 is made of a copper material and is stable to tap water, and thus is used as a water pipe for tap water. Also, by using copper material,
It has excellent thermal conductivity and good heat exchange characteristics.

As the copper material, in addition to high-purity copper, brass (copper alloy) obtained by adding zinc to copper is used.
In addition, alloys of copper and other metals are used. In the case of these alloys, their components are not particularly specified.

The water pipe 17 may be made of a steel material (steel). When a steel material is used, the mechanical strength is high and the coefficient of thermal expansion is low as compared with copper and aluminum, so that it is also excellent in heat resistance.

As shown in FIG. 3, the fins 43 are formed by pressing or punching a substantially rectangular steel material. Examples of the steel material include JIS SS33O, SS400, SS490 containing 0.050% by weight or less of phosphorus (P) and 0.050% by weight of sulfur (S), 0.30% by weight of carbon (C), A JIS SS54O steel material containing 1.60% by weight or less of manganese (Mn), 0.040% by weight or less of phosphorus (P), and 0.040% by weight or less of sulfur (S) is used. In addition, various things can be used according to a use.

The fin 43 is provided with three water pipe holes 47 into which the water pipe 17 is to be inserted, in each of the upper and lower rows. Above each water pipe hole 47, a brazing hole 49 into which a brazing material is inserted is formed. As the brazing material, rod-shaped copper brazing or nickel brazing is used, and is eluted in a furnace at the time of manufacturing, and the water pipe 17 is connected to the fin 43.

The fin 43 has a projection 5
As shown by an arrow A in FIG. 3, the heat gas flow guides the flow path of the heating gas closer to the water pipe 17 and makes the flow path meander or generates a turbulent flow to increase the heat exchange efficiency. I have. As shown in FIG. 4, the protrusions 51 and 53 project the surface of the fin, form a flow path of the heating gas, and increase the surface area of the fin by swelling.
The heat exchange area has been increased. Note that FIG.
Although only the protrusion 51 is shown, a similar protrusion is formed for the protrusion 51. The projection 53 is cut out on both sides to protrude, bulges into a convex shape as shown by reference numeral 53a in FIG. 4, or has a truncated cone shape with an upper base punched out as shown by reference numeral 53b. There may be. That is, since the steel material has a high degree of freedom in forming, various projections can be easily formed.

Next, the operation of the present embodiment will be described. During the hot water supply operation, water is introduced from the water supply pipe 9 into the water pipe 17 of the heat exchanger 1. On the other hand, when the gas is ignited in the heating unit 7, the combustion gas passes between the fins 43 of the heat exchanger 1 and heats the water in the water pipe 17.

In the heat exchanger 1, the heating gas flows as shown by the arrow A in FIG. 3, but the heating gas from the heating unit 7 directly passes through the lower water pipe 17. Then the heated gas is projected 5
It is guided around the water pipe 17 of the upper stage by 3 and 51, and passes between the fins 43. The surface of the fin 43 is in contact with the heating gas to receive heat conduction.
3, 51 are swelled as shown in FIG.
Since the surface area of the fin 43 is practically large and the heat exchange surface is large, it is possible to receive much heat from the heating gas.

In the water heater 3, the temperature of the flame formed in the heating section 7 is 1500 ° C. to 1800 ° C., and the heating gas formed there is also a high temperature of about 1000 ° C. Therefore, deformation and cracks are less likely to occur due to high thermal expansion and mechanical strength against such high heat, durability in a heat cycle having a large temperature difference is excellent, and life can be extended.

At the time of manufacturing, since a steel material is used, such a bulging projection can be easily formed by press working or the like.
In addition, since steel is superior in surface stability as compared with metals such as copper, surface treatment is easily performed. Therefore, in order to impart corrosion resistance at high temperatures, painting and plating can be easily performed.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention. For example, as shown in FIG. 5, the projections 53 (or 51) may alternately protrude on both sides of the fin 43, or cut out and protrude, and as shown in FIG. However, the same effect as in the above-described embodiment can be obtained.

Further, as shown in FIG. 7, a configuration may be adopted in which unevenness 57 is formed on the entire fin 43 to increase the surface area.

Further, in the above-described embodiment, the description has been made by using a water heater as an example. However, the present invention is not limited to this, and it is also possible to perform heating and cooling by cooling water, flowing an acidic aqueous solution or an alkaline aqueous solution through a water pipe. A similar effect can be obtained.

[0038]

According to the first aspect of the present invention, in a heat exchanger for water or an aqueous solution for exchanging heat in a water pipe, the water pipe is made of a copper material or an iron alloy.
The water tube is stable against water or an aqueous solution flowing through the tube. Since the fin is made of an iron alloy, it has good workability, can easily form protrusions and folds, and can improve heat exchange characteristics. Further, plating and surface treatment are easy, and the durability of the heat exchanger is improved, and the heat exchanger can be adapted to a heat cycle having a large temperature difference. Further, iron alloys used for the fins, for example, steel and special steel are inexpensive as compared with copper and aluminum, so that manufacturing costs can be reduced.

According to the invention described in claim 2, according to claim 1
In addition to the invention described in (1), the fins are formed with protrusions such as overhangs, protrusions, and notches, so that the heat exchange area can be increased and the flow path of the heat exchange medium can be efficiently formed.

According to the third aspect of the present invention, since a steel material or a special steel material is used as the iron alloy used as the fin material, it is particularly suitable for environmental characteristics such as use in a heat cycle having a large temperature difference. The material can be selected.

The invention according to claim 4 is characterized in that the fins can be used even when the temperature difference in the heat cycle is large, such as when the water pipe is used for hot water supply or circulation of hot water or hot water in a bath. , Deformation and cracks hardly occur. Further, if necessary, surface treatment such as plating can be easily performed to prevent corrosion.

[0042]

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a water heater according to an embodiment of the present invention.

FIG. 2 is a perspective view of a heat exchanger used in the water heater shown in FIG.

FIG. 3 is a plan view of a fin.

FIG. 4 is a cross-sectional view showing a part of the heat exchanger.

FIG. 5 is a cross-sectional view of a fin according to another embodiment.

FIG. 6 is a cross-sectional view of a fin according to another embodiment.

FIG. 7 is a cross-sectional view illustrating a part of a heat exchanger according to another embodiment.

FIG. 8 is a cross-sectional view showing a part of a conventional heat exchanger.

[Explanation of symbols]

 Reference Signs List 1 heat exchanger 39 water pipe 43 fin 51, 53 projection 57 unevenness (projection or fold)

Claims (4)

[Claims] A plurality of fins spaced apart from each other;
A water pipe fitted with these fins and through which water or an aqueous solution flows, and a heat exchanger for water or an aqueous solution for exchanging heat in the water pipe, wherein the water pipe is made of a copper material or an iron alloy; The heat exchanger for water or an aqueous solution, wherein the fin is made of an iron alloy. 2. The heat exchanger is a gas-liquid heat exchanger formed by passing a gas as a heat exchange medium between the fins,
The heat exchanger for water or aqueous solution according to claim 1, wherein the fin has a large number of protrusions formed by overhangs or notches. 3. The heat exchanger for water or aqueous solution according to claim 1, wherein the iron alloy used for the fin is a steel material or a special steel material. 4. The water pipe according to claim 1, wherein water such as tap water or tap water is circulated through the water pipe, and gas heated by a burner is passed between the fins to heat the water. A heat exchanger for water or an aqueous solution according to claim 1.