JPS60134199A - Heat exchanger - Google Patents

Abstract

PURPOSE:To raise the durability and performance of a heat exchanger by preventing the lowering of heat exchanging efficiency as well as the occurrence of corrosion (generation of blue-color water) for long periods of time by a method in which a specific composition of coating layer 2 is formed on the surface of the copper heating part being in contact with water. CONSTITUTION:A paint, prepared by mixing a binder or a mixture of an acrylic resin, melamine resin, and an epoxy resin, any one or mixture of SiC powder and Al2O3 powder, and any one glass powder of Na2O.SiO2, Li2O.SiO2, and K2O.SiO2, is coated on the surface to be touched by water of a copper heating part 1 and hardened by heating to form a coating layer 2. A binder composed of a mixture of acrylic resin, melamine resin, and epoxy resin is further coated on the surface of the coating layer 2 in which the powder 2a of SiC and Al2O3 and the glass powder 2b are uniformly dispersed and then hardened by heating to form a coating layer 3.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is useful for copper heat transfer parts used in hot water supply equipment, heating equipment, etc. This relates to a heat exchanger.

Conventional configuration and its problems.

Conventionally, copper, which has good workability and thermal conductivity, and is resistant to corrosion by ordinary tap water, has often been used for the heat transfer part of this insert heat exchanger. However, in a water environment such as groundwater where the pH (hydrogen ion degree) is 7 or less and there are large amounts of anions such as free carbonate (carbon dioxide gas dissolved in water), chlorine ions, and nitrate ions, 111J copper or Jfd. eaten. 'Copper ions eluted by corrosion react with fatty acids such as soap to form blue copper complex salts, which discolor water blue, and the copper complex salts adsorb onto towels used in baths, turning the towels blue. There were problems such as discoloration.

One way to prevent corrosion of copper is to add a rust inhibitor such as a silicate or phosphate polymer to water and form a protective film of the rust inhibitor component on the copper surface. Since the coating deteriorates and peels off in a short period of time, it is necessary to periodically add a rust preventive agent, which is difficult to manage in general households.

1. The method of plating metals such as nickel and tin on the copper surface is in the highly corrosive acidic water environment mentioned above. Therefore, the plating layer corroded in a short period of time, and due to peeling and wear of the plating layer, there was a problem that copper corrosion occurred frequently.

Furthermore, when coating with an organic or ζj1ξ mechanical binder, there are many pinholes in the coating layer itself, and copper corrodes through these pinholes, so the coating layer needs to be as thick as 100 μm or more.
This configuration has problems such as poor thermal conductivity and extremely low heat exchange efficiency.

The present invention, which is the first aspect of the invention, solves all such problems and lasts for a long time! l
The purpose is to prevent water corrosion (generation of blue water) of heat exchangers made of copper heat transfer members, prevent a decrease in heat exchange efficiency, and fully improve the durability and performance of the equipment.

Structure of the Invention The present invention provides a binder made of acrylic resin, melamine resin, and epoxy resin on the surface of a copper heat transfer part that comes into contact with water, and a binder made of SiC, At203 (Q at least 1A, !1).
More than 1! A coating layer is formed with a paint made by dispersing and mixing powder ll, any one of l'Ja2○, Li2O, and 2○, and glass powder made of SiC2, and on top of this, acrylic resin, melamine resin, and epoxy resin are applied. The coach ink layer is formed using a different binder.

With this configuration, even if the heat exchanger is used in a highly corrosive water environment such as groundwater, two layers of coordinog are formed on the surface of the copper heat transfer part that comes into contact with water. Direct contact between water and copper heat transfer jGfs material is +H
B+i (Along with the pinhole of the 1st riverbed layer) Even if 1 acidic I94 in the water is received through Lyf, it is neutralized by the glass powder in the coating layer, so the corrosivity disappears. It is possible to prevent corrosion of the copper heat transfer member, prevent water and towels from turning blue due to JN corrosion of copper, and improve the durability of the heat exchanger. In addition, since the coating layer contains a powder having excellent thermal conductivity, it is possible to completely reduce the heat exchange efficiency.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The figure is a partial sectional view of a heat exchanger showing an embodiment of the present invention. In the figure, 1 is a copper heat transfer member, and a mixture of acrylic resin, melamine resin, and epoxy resin is used as a binder on the surface of the copper heat transfer member 1 that comes into contact with water.
This is combined with either SiC powder or At203 powder, especially a mixture of these, and Na2○, SiO2, Li2O.
・Sio2. The coating layer 2 is formed by adding any one type of glass powder of 20.5i02 to the glass, applying a dispersed mixture, and curing by heating. In this coating layer 2, powder 2a made of Sic and At203 and glass powder 2b are uniformly dispersed.

Furthermore, the surface of the coating layer 20 is a mixture of acrylic resin, melamine resin, and epoxy resin! A coating layer 3 is formed by dispersing a binder fc and curing it by heating.

In this configuration, the acrylic resin, melamine resin, and epoxy resin used as binders in the coating layers 2 and 3 are heat-cured to form a three-dimensional dense network structure, which reduces the permeation of water molecules and acidic corrosion factors. Moreover, since the glass transition point is low, the wettability to the copper heat transfer member 1 is improved, and the pinhole/L in the coating layer is improved.
By forming these coating layers 2 and 3, it is possible to largely prevent the infiltration of acidic corrosion factors that exist in large quantities in ground water, etc. Attack f13 of the acidic food factor r on the heating member 1 can be almost completely prevented. On the other hand, since it is impossible to completely remove coating layers 2 and 3 (pinholes), the acidic corrosion factor slightly enters through these pinholes, but it is dispersed in coating layer 2. Na2O+ L contained in the glass powder 2b
i 20 , the acidic corrosion factor is consumed within the coating layer 2 to cause a summation reaction with the 771/force of K2O. Therefore, corrosion on the copper heat transfer part side 1 is completely prevented, and copper ions are no longer eluted into the water, causing corrosion of copper. It is possible to prevent discoloration of water, towels, etc. caused by nitrogen and severe corrosion of heat exchangers. - A coating layer 3 is formed on the second part of the coaching ink layer 3, and since this coaching ink layer 3 is only a binder, the number of pinholes in the coaching ink layer 3 is extremely small (9), which prevents the infiltration of the acidic corrosion factor. is a small amount, so the consumption of the alkali content of Na2O, Li 2○, and 2○ necessary for the neutralization reaction of the glass powder 2b present in the coating material 2 is small, and the neutralization is carried out over a long period of time. function can be maintained.

1. The coating layer 2 is made of SiC with good thermal conductivity.
Since the fraction 2a of AA2○3 is dispersed, the excellent thermal conductivity of copper is not impaired, resulting in excellent copper heat transfer 7) 3B efficiency 1
It has heat transfer from water to water, and high heat exchange efficiency can be achieved.

Furthermore, since epoxy resin gold is used as one of the binders in Coating 1, 2 and 3, it is possible to achieve excellent adhesion to the base, and prevent peeling between the layers over a long period of time. can.

Effects of Investigation The heat exchanger of the present invention has a two-layer coping ink layer with excellent corrosion resistance and thermal conductivity formed on the surface of the copper heat transfer member. Since certain copper corrosion is eliminated, the elution of copper ions into water can be prevented, and water and towels can be prevented from turning blue.

(2) Damage to the heat exchanger due to corrosion can be completely prevented, and durability can be greatly improved.

(3) Since the excellent thermal conductivity of copper is not impaired, it is possible to completely prevent a decrease in heat exchange efficiency.

It has the following effects.

[Brief explanation of drawings]

The figure shows an embodiment of the present invention, a heat exchanger, 7 parts, 1υ1
This is a diagram. 2...Coachings So, 3...Coating J So, 2a...Sic, At20
3 powder, 2b...Glass powder book.

Claims (1)

[Claims] A binder consisting of acrylic resin, melamine resin, and epoxy resin is applied to the surface of the copper heat transfer part that comes into contact with water.
A coating layer is formed with a paint obtained by dispersing and mixing a powder made of at least one of iC, At203, one of l'J a2○, Li2O, and a glass powder made of SiO2, and then a coating layer is formed on the coating layer. A heat exchanger with a coating layer formed with a binder made of acrylic resin, melamine resin, and epoxy resin.