JP2001183087A - Heat exchanger of combustion equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means capable of attaining a uniform coating by a stable manufacturing method and having a superior environmental safety characteristic through means replacing with a lead dipping process in order to improve anti- corrosion characteristic of a heat exchanger used in a combustion device. SOLUTION: In a heat exchanger of combustion equipment in which it is made of copper material (a copper plate, and a copper pipe), a heat accepting pipe is inserted into and a passed through through-pass holes of plate fins arranged in rows in a casing, opening ends of the heat accepting pie are connected by a U-shaped pipe, a water flow passage extending from a water supplying inlet to a hot water supplying outlet is formed and assembled, wherein the assembled passage is fed into an electrical furnace and desired connecting portions are brazed, either a nickel plating or a tin plating is applied after the brazing step to form a film with a thickness of several μ to several tens μon the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger incorporated in a combustion appliance such as a water heater or a water heater.

[0002]

2. Description of the Related Art A heat exchanger of a combustion appliance is formed by joining a large number of plate fins at predetermined intervals on an outer periphery of a heat receiving tube through which water flows in a tube, and is formed in a through hole of the plate fins arranged in a box. Insert the heat receiving tube, connect the open end of the heat receiving tube with a U-shaped tube, form a water passage from the water supply inlet to the hot water supply outlet, assemble it, put it into the electric furnace, plate fin and heat receiving tube, It is manufactured by brazing the open end of the heat receiving tube and the U-shaped tube. Generally, a copper material (copper plate, copper tube) is used as a material of such a heat exchanger. However, in a burning appliance using a fuel containing a sulfur component such as kerosene or a production gas, the sulfur component in the exhaust gas and the surface of the heat exchanger are combined. There is a risk that sulfuric acid components generated by a chemical reaction with attached dew condensation water will erode the copper material, causing fin defects and holes. To prevent this, lead dipping is performed after the brazing step, and the surfaces of plate fins, heat receiving tubes, and the like are coated to improve corrosion resistance.

[0003]

However, such a lead-dip coating has a non-uniform treated surface,
The workability is inferior, for example, a removal operation for removing the partial pool after the treatment is required, and the use of lead is not a preferable means from the viewpoint of environmental safety.

An object of the present invention is to solve these problems. In order to improve the corrosion resistance of a heat exchanger used for a burning appliance, a uniform production method is provided by means instead of a lead dipping treatment. It is an object of the present invention to provide a means for obtaining a coating which is excellent in environmental safety. Also, in a combustion appliance using a clean fuel such as natural gas, when used as a latent heat recovery heat exchanger incorporated for recovering latent heat in exhaust gas for the purpose of energy saving, nitric acid adhering to the heat exchanger surface It is an object of the present invention to provide a heat exchanger having a sufficient corrosion resistance even to dewed water in a system.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention has been made using a copper material (copper plate, copper tube),
The heat receiving tube is inserted into the through holes of the plate fins arranged in the box, the open end of the heat receiving tube is connected with a U-shaped tube, and a water passage from the water supply inlet to the hot water supply outlet is formed and assembled. In a heat exchanger of a combustion appliance, which is manufactured by brazing required joints, a nickel plating is applied after the brazing process to form a film having a thickness of several μ to several tens of microns on the surface. It is a feature.

[0006] The heat exchanger for a combustion appliance according to the present invention comprises:
Instead of the nickel plating, tin plating can be applied. Hereinafter, the configuration of the present invention will be specifically described with reference to the embodiments of the drawings.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an embodiment of the present invention showing a heat exchanger incorporated in a gas-fired appliance. In the figure, a plate fin 12 having a plurality of through holes formed therein is formed in a box 10.
Are arranged in a predetermined number, the heat receiving tubes 13 are inserted into the aligned through holes, the open ends of the heat receiving tubes 13 are connected by a U-shaped tube 14, and the heat receiving tubes 13 A pipe 16 is wound, and the end of the peripheral pipe 16 is connected to the heat receiving pipe 13 to form a water passage from a water supply inlet 17 to a hot water supply outlet 18. As a material of these members, a copper material (copper plate, copper tube) is used.

After assembling the heat exchanger in this manner, a brazing material is placed at a predetermined position and charged into an electric furnace, where the heat receiving tube 13 and the plate fins 12, the end of the heat receiving tube 13 and the U Required joints such as the pipe 14, the inner body 11 and the peripheral pipe 16 are brazed.

[0009] The present invention, after such a brazing step,
Instead of the conventional lead dipping treatment, the surface of the heat exchanger is subjected to electroplating by nickel plating or tin plating. This plating process is performed on the surfaces of the heat exchanger except for the pipe ends forming the water supply inlet 17 and the hot water supply outlet 18, ie, the inner and outer peripheral surfaces of the box 10 and the inner body 11, the heat receiving tube 13, the U-shaped tube 14, and the like. And on the entire exposed surface such as the outer peripheral surface of the peripheral pipe 16 and both side surfaces of the plate fin 12. FIG.
Next, a state where both side surfaces of the plate fin 12 are covered with the plating layer 20 by such plating treatment is shown. The thickness of the plating layer 20 is several μm to several tens μm.

The heat exchanger of the present invention is completed through a plating process, and the manufacturing process is shown in FIG. The heat exchanger completed in this way is installed in the equipment and piped, the supply water from the water supply inlet 17 is heated, and the hot water supply outlet 1 is heated.
Take water from 8.

[0011]

As described above, according to the present invention, after the brazing step, the surface is subjected to nickel plating or tin plating to form a coating having a thickness of several μ to several tens of microns. It is possible to provide a heat exchanger in which the entire exposed surface of the exchanger is coated and has sufficient corrosion resistance to sulfuric acid and nitric acid components.

Further, since the material of the member is a copper material, the plating layer 20 is excellent in adhesion and a uniform coating can be obtained by plating, so that the workability is improved as compared with the conventional lead dipping. This is a preferable means from the viewpoint of environmental safety because it can be used and lead is not used.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of an embodiment of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is an enlarged sectional view showing a state where both side surfaces of a plate fin are covered with a plating layer.

FIG. 4 is a flowchart showing a process of manufacturing a heat exchanger according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Box 12 Plate fin 13 Heat receiving pipe 14 U-shaped pipe 17 Water supply inlet 18 Hot water supply outlet

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F28F 19/06 F28F 19/06 C

Claims (2)

[Claims] 1. A heat receiving tube 13 is manufactured by using a copper material (copper plate, copper tube), and is inserted into a through hole of a plate fin 12 aligned in a box 10, and an opening end of the heat receiving tube 13 is U-shaped. In a heat exchanger of a combustion appliance, which is connected by a pipe 14, forms a water passage from a water supply inlet 17 to a hot water supply outlet 18 and assembles it, puts it into an electric furnace, and brazes necessary joints to produce the same. A heat exchanger for a combustion appliance, wherein a nickel coating is applied after the brazing step to form a coating having a thickness of several μm to several tens of microns on the surface. 2. The heat exchanger for a combustion appliance according to claim 1, wherein tin plating is applied instead of nickel plating.