JPH0224050Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a corrosion protection device for electric water heaters, heat storage tanks, and other hot water tanks that are widely used for general household and commercial purposes.

Structure and Problems of Conventional Example A conventional electric water heater, for example, shown in FIG. In order to prevent corrosion of the sheathed heater 2, an externally powered corrosion protection device having only one electrode 3 was provided near the sheathed heater 2. 4 is a power supply, 4a is a rectifier, 4b is a smoothing capacitor, 4c
is a resistor, 5 is a water tap, and 6 is a hot water tap. However, there was a problem in that the glass lining was self-depleted by the hot water over time, increasing the amount of exposed iron and corroding the inner surface of the tank. In order to solve this problem, attempts have been made to add an electrode 3a as shown in FIG. 2 to uniformly protect the inner surface of the tank from corrosion. However, this device skips the glass lining because the current is too large compared to a single electrode.
This has the disadvantage that it actually promotes the exposure of iron and accelerates the progress of corrosion.

Purpose of the invention The purpose of the invention is to eliminate these conventional drawbacks, and to provide a corrosion protection device for a hot water tank that can more effectively prevent corrosion on the inner surface of the hot water tank.

Structure of the invention This invention consists of a first electrode installed in a hot water tank whose inner surface is glass-lined and to which a voltage is applied, and a second electrode installed in the hot water tank.
an electrode, a sensing element that is installed in the hot water tank and generates an electric signal when it comes into contact with the hot water due to wear of its own glass-lined surface, and a voltage is applied to the second electrode by the electric signal of this sensing element. It is equipped with a driving means for

According to the configuration of this invention, the sensing surface of the sensing element is glass-lined, and in the initial stage of use, the glass-lining surface is not worn out and is in a non-conducting state, so that the second electrode is No voltage applied. When the glass lining surface wears out over time and the conductive portion of the sensing element comes into contact with hot water and generates an electrical signal, a voltage is applied to the second electrode. At this time, the glass lining on the inner surface of the tank is also worn out, and the exposed portion of the tank body is increasing, so that corrosion can be more effectively prevented by allowing current to flow through the second electrode. On the other hand, in the initial state, only the first electrode is conductive, so overcurrent can be prevented, and a more effective corrosion protection device can be provided with less acceleration of deterioration of the unused glass lining. .

DESCRIPTION OF EMBODIMENTS An embodiment of this invention is shown in FIG. That is, 7a is a first electrode for corrosion protection provided below the hot water tank 1, 7b is a second electrode for corrosion protection provided above the hot water tank 7b, and 8 is a detection sensor whose surface is glass-lined. The other elements are the same as those shown in FIG. 2, except that 9 is a driving transistor, 10 is a relay, and 11 is a relay contact.

When the tank is filled with water, a current flows through the first electrode 7a to prevent pitting and corrosion of the sheathed heater 2 and the like. On the other hand, at the initial stage of use, the surface of the sensing element 8 that comes into contact with water is glass-lined, so it does not come into contact with water, so the transistor 9 and relay 10 do not operate and the contact 11 is open. When the glass lining deteriorates and wears out over time, the conductive part of the sensing element 8 comes into contact with hot water, causing a signal current to flow to the base of the transistor 9. This causes current to flow through the transistor 9, which activates the relay 10 and closes the contact 11. It is closed, voltage is applied to the second electrode 7b, and current flows. At this time, the glass lining on the inner surface of the upper tank has also begun to deteriorate and wear out, and the anticorrosion current flows from the second electrode 7b in a timely manner, making it possible to effectively protect the inner surface of the tank from corrosion. In this way, corrosion protection on the inner surface of the hot water tank can be made more effective.

Effects of the invention The anti-corrosion device for a hot water tank of this invention can automatically increase the current even if the glass lining deteriorates and wears out during long-term use, improving the anti-corrosion effect and extending the life of the tank. Furthermore, since corrosion is prevented from the initial stage of use without passing an excessive current, there is no cracking of the glass lining due to hydrogen generation, and deterioration can be suppressed.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams showing a conventional corrosion protection device for a hot water tank, and FIG. 3 is a schematic diagram of an embodiment of this invention. 1...Hot water tank, 2...Sheathed heater, 4...
...Power source, 7a...First electrode, 7b...Second electrode, 8...Detection element, 9...Transistor, 10
...Relay, 11...Contact.

Claims (1)

[Scope of utility model registration request] a first electrode installed in a hot water tank whose inner surface is glass-lined and to which a voltage is applied;
a second electrode installed in the hot water tank; a sensing element installed in the hot water tank that generates an electrical signal when it comes into contact with hot water due to wear of its own glass-lined surface; and an electric signal of the sensing element. A corrosion protection device for a hot water tank, comprising: a drive means for applying a voltage to the second electrode in response to a signal.