JPS589982A - Enamelled vessel body - Google Patents

Abstract

PURPOSE:To provide an enameled vessel body having superior hot water resistance by forming the 1st enamel layer contg. SiO2, B2O3 and other contg. compds. on the inside surface of a steel plate constituting the vessel body and further forming the 2nd enamel layer contg. SiO2 and other inorg. compds. thereon. CONSTITUTION:The 1st enamel layer 7 constituted of the glaze contg. 30-40% SiO2, 10-20% B2O3 and other inorg. compds. is formed on the inside surface of a steel plate 6 constituting a vessel body 1 for electric water heater. The 2nd enamel layer 8 constituted of the glaze contg. no B2O3 at all and contg. 60- 70% SiO2 and other inorg. compds. is further formed on said layer 7 on the inside surface of the steel plate 6 in the part upper than the heater 2 of the body 1. As a result, the layer 8 develops higher resistance force to hot water than the layer 7 and contributes to the marked prolongation of the life of the body 1 itself. Here, 3 in the figure denotes a hot water feed port, 4 a water feed port, and 5 an electrode bar for electrolytic protection.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an enameled can body whose inner surface is enameled.

Generally, the inner surface of a hot water supply can such as an electric water heater is treated with enamel, which is sanitary in light of its intended use and has excellent corrosion resistance.

Furthermore, in order to reduce the number of pinholes, conventionally, as shown in FIG.
4 ochi, form the first enameled layer 12 composed of a glaze containing 10-20% B203 and other inorganic compounds, and further form the first enameled layer 12 with the same glaze as the first enameled layer 12. A second hollow layer 13 was formed. However, this hollow layer is 12.1
No. 3 has the problem that the enamel can melts in a short period of time in the high-temperature part of the electric water heater, exposing the iron material and causing red rust. To solve this problem, the conventional method was to add a sacrificial anode rod or cathodic protection electrode to the high-temperature part of the enamel can to prevent red rust on the tank. However, the anticorrosion current is 6 to 20 mAβ in a normal enamel can, and this is the limit considering the economical efficiency of constant energization. Therefore, there was a limit to the ability to significantly extend the life of the can body by exposing the iron fabric.

This book 11' is an attempt to solve the above-mentioned conventional problems by improving the glaze that forms the enamel layer.Hereinafter, this bisho will be explained based on a drawing showing one embodiment thereof.

In Figure 1, 1 is the can of an electric water heater;
A heater 2 is provided inside and below. 3 is can body 1
4 is a water supply port provided on the upper side wall of the can body 1; 6 is a water supply port located above the heater 2;
This is a cathodic protection electrode rod attached to the side wall of the

FIG. 2 shows a cutaway portion of the can body 1 located below the heater 2 in FIG. 1, where 6 is a steel plate;
The inner surface of this steel plate 6 contains SiO230~40, B2
A first hollow layer 7 is formed of a glaze containing 10 to 2o% of O3 and other inorganic compounds. FIG. 3 is a cutaway view of the portion of the can body 1 located above the heater 2 in FIG. So, this second
The hollow layer 8 is provided to improve the hot water resistance of the high temperature section. And this 20th hollow layer 8 contains no B2O3 and has Si0260~7
It is composed of a glaze containing Ochi and other inorganic compounds.

FIG. 4 shows the glaze in the first hollow layer 7 and the second layer.
This test shows the results of a test conducted to compare the cumulative loss of glaze dissolution in Enamel One Layer 8.
Pure water was continuously boiled and the amount dissolved was measured at regular intervals. As is clear from Fig. 41, the second hollow layer 8 exhibits stronger resistance to hot water than the first hollow hollow layer 7, and as a result, the life of the can body itself is greatly extended. be able to.

As described above, according to the present invention, a first hollow layer made of a glaze containing 30% to 40% SiO, 1% to 20% B2O, and other inorganic compounds is formed on the inner surface of the steel plate constituting the can body. , further on top of the first hollow layer, S 1
Since the second enamel layer is formed of a glaze containing 0260 to 7o and other inorganic compounds, it is possible to provide an enamel can body with unprecedented hot water resistance.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an electric water heater having an enamel can according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of the part of the can located below the force 6 heat heater, and Fig. 3 is the same. FIG. 4 is a graph showing the test results of cumulative weight loss by melting, and FIG. 6 is a cross-sectional view of a conventional enamel can body. 1... Hoe a-can body, 2... Heater (heating source), 7... First enamel layer, 8...
...Second hollow layer. Name of agent: Patent attorney Toshio Nakao &? i-ka11
Famous school Figure 1 Figure 2 Figure 13

Claims (2)

[Claims] (1) 810230-40 on the inner surface of the steel plate that makes up the can body
%, 820310 to 20% and other inorganic compounds, and on top of the first enameled layer, a glaze containing 5io260 to 70% and other inorganic compounds. An enamel can body characterized by forming a single layer of second enamel. (2) The enameled can body according to claim 1, wherein the second enameled single layer is formed only above the heating source of the can body having a heating source.