JPS58123096A - Heat exchanger - Google Patents

Abstract

PURPOSE:To improve a heat exchanging characteristic, as well as to enhance resistance to heat and to corrosion, and to largely increase durability, by applying heat-resistant paint, containing ultrafine metallic powder, to the surface of a base material, in a heat exchanger used for a water heater and others. CONSTITUTION:A heat exchanger is composed in such a manner that a heat absorbing part (fins) 3 is provided to the top of a heating shell 2 which forms a combustion chamber, and heat exchanging pipes 4 are wound up around the outside of the heating shell 2, being inserted into the fins 3. A paint, which is heat- resistant and acid-resistant, and into which ultrafine metallic powder is dispersed, with inorganic polymer being used as a binder, is applied to the surface of a base material of heat exchanger, to form a coating layer by baking. With such an arrangement, heat exchanging ability is increased, because ultrafine metallic powder is included the coating layer, together with resistance to heat, resistance to corrosion, and durability being enhanced in the heat exchanger.

Description

[Detailed Description of the Invention] The present invention relates to a heat exchanger used in water heaters, instantaneous water heaters, etc., and particularly aims to provide a heat exchanger with excellent corrosion resistance and heat exchange characteristics. It is.

Heat exchangers used in conventional water heaters, instantaneous water heaters, and the like are generally made of copper or the like, with lead hot-dip plated on the surface.

The role of this plating layer is to dissolve and condense sulfur oxides and nitrogen oxides in the combustion gas into dew water, creating H2SO4 and HN.
O, which prevents corrosion of the base material of the heat exchanger, improves the adhesion between the heating cylinder that forms the combustion chamber and the pipe wrapped around this heating cylinder, and increases heat absorption. be.

However, with hot-dip lead plating, it is impossible to avoid some pinholes from forming in the plating layer.

The base material oxidizes through these pinholes and suffers from acid attack, shortening the lifespan of the heat exchanger.

Also, Go, CO2, NOx contained in combustion gas
The surface of the lead plating becomes lead carbonate, basic lead carbonate, −
It becomes lead oxide and accumulates significantly on the heat absorption fins, which are the main part of the heat exchanger, obstructing the flow of combustion gas, causing incomplete combustion, or falling in the form of powder, making it unhygienic. It was also not favorable.

The above-mentioned drawbacks of the conventional heat exchanger are solved by coating the base material surface of the heat exchanger of the present invention with a heat-resistant paint whose binder is an inorganic polymer in which ultrafine metal powder is dispersed, and then baking it to form a coating layer. be.

An embodiment of the present invention will be described below based on the drawings.

In the figure, 1 is a main body of a heat exchanger, and within this main body 1 is provided a heating device 2 that forms a combustion chamber. 3 is a fin used as a heat absorption part, and is provided on the -F side of the heating part 2. 4 is a heat exchange pipe.

It is wrapped around the outer periphery of the heating member 2 and inserted through the fins 3.

The entire surface of the base material of the heat exchanger constructed in this way is coated with a heat-resistant, acid-resistant paint that uses an inorganic polymer as a binder in which ultrafine metal powder is dispersed. For example, Sumiceram from Sumitomo Chemical Co., Ltd. is used as the paint, and ultrafine metal powder from Shinku Yakiniku Co., Ltd. is used as the ultrafine metal powder. These are dispersed and mixed using a ball mill, attritor, etc. for a predetermined period of time, and then a solvent is added to stabilize the mixture. Adjust the viscosity to make it into a paint. Then, the base material of the heat exchanger is degreased, and this paint is applied by spraying or dipping, and then baked to coat the entire surface of the heat exchanger.

By configuring the heat exchanger in this way, the burner (not shown) disposed at the bottom of the combustion chamber can absorb combustion products such as Go, CO2, sulfur dioxide, and NO.
x etc. do not come into direct contact with the base material of the heat exchanger,
Also, H2SO4, HN, which is dissolved and condensed in dew water,
Corrosion of the base material can also be prevented from O3 and the like.

Furthermore, since the coating film has excellent heat resistance and acid resistance, it is possible to improve the durability of the heat exchanger.

Furthermore, since the ultrafine metal powder has an extremely fine particle size of 300 to 700, the metal powder is uniformly dispersed in the paint, and the Muq, Muα, and Qu contained therein have excellent thermal conductivity. Therefore, it is possible to improve heat exchange characteristics.

In addition, the coating film of the heat exchanger in this example was heated to 500°C.
It can withstand moderately high temperatures and heats up.

Even after repeated cooling cycles, the coating remains firmly attached to the base material without peeling or falling off.
There will be no deterioration or cracking of the base material.

Furthermore, unlike lead plating, no corrosion products are produced, making the heat exchanger excellent in terms of hygiene.

As is clear from the above description, the heat exchanger of the present invention is.

(1) Since it has excellent heat resistance and corrosion resistance, the durability of the heat exchanger can be greatly extended.

(2) Since ultrafine metal powder is uniformly dispersed in the heat-resistant paint, heat exchange characteristics can be improved.

(3) Since the paint coated on the surface of the heat exchanger has excellent acid resistance, it is hygienic even when used in water heaters and instant water boilers without being attacked by acids contained in dew water.

(4) Since the work of coating the heat-resistant paint on the surface of the heat exchanger can be done by a general coating or impregnation method, it has advantages such as excellent workability and mass production, and it is possible to reduce costs. It will be done.

[Brief explanation of the drawing]

The figure is a perspective view of a heat exchanger showing one embodiment of the present invention. 1... Main body, 2... For heating, 3...
...Fin (heat absorption part), 4...Heat exchange pipe.

Claims (1)

[Claims] A heat-absorbing section is provided on the top of the heating cylinder that forms the combustion chamber to form a heat exchanger, and the surface of the base material of this heat exchanger is coated with a heat-resistant paint whose binder is an inorganic polymer in which ultrafine metal powder is dispersed. Heat exchanger.