JPS62294913A - Water level alarm - Google Patents

Abstract

PURPOSE:To detect that a water level is a definite value or less to display the same, by providing a temp. switch having predetermined operational temp. for detecting the water temp. in the communication pipe having a heat insulating structure provided to a container in close vicinity of the bottom part thereof to constitute a combination structure of said switch and a display lamp. CONSTITUTION:A communication pipe 6 is formed by connecting L-shaped pipes 7, 7 respectively comprising heat insulating material to the upper and lower communication holes of an inner container 1 and connecting a heat conductive straight pipe 8 between said L-shaped pipes 7, 7. When the water in the inner container 1 holds a water level A or more before heating, a temp. switch 9 is closed and a display device 11 lights but, after a current is supplied to a heater, water temp. exceeds the operation point of the temp. switch 9 within a short time to put out lights. When several min is further elapsed, the water temp. reaches set temp. When the quantity of water in the inner container 1 is reduced because of the use of hot water to reach the water level A or less, the straight pipe 8 is not contacted with hot water to be cooled rapidly and the temp. thereof becomes lower than the operation point of the temp. switch 9. By this mechanism, the temp. switch 9 is closed and the display device 11 lights to display that the quantity of water in the inner container 1 becomes lower than the water level A.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) This invention relates to a water level alarm, and in particular to a water level alarm suitable for containers containing high temperature liquids such as electric heating pots. Regarding.

(Prior art) Conventionally, the amount of water in the inner container of an electric heating pot was measured by providing communication pipes made of glass or the like that communicated with the inner container at the top and bottom, and by observing the height of the water level in the communication pipes through the outer container. I'm checking it out. Furthermore, since it is difficult to confirm the height of the water surface in a transparent communication pipe, a background board with a striped pattern or the like is installed behind the communication pipe to make it easier to confirm the water surface.

(Problems to be Solved by the Invention) However, this communication pipe has a drawback that it is difficult to determine which water volume is empty or nearly full. For this reason, a mistake may occur in which a nearly empty state is judged as a full water state and electricity is turned on without supplying water. Of course, abnormal overheating in an empty state can be prevented by a temperature switch, but if you are not aware of it, the problem remains that the necessary amount of hot water is not stored when you need it.

An object of the present invention is to provide a water level alarm that can detect and display that the water level is below a certain level (for example, an empty or nearly empty water level) using a temperature switch.

(Means and effects for solving the problem) The water level alarm according to the present invention is provided with a communicating pipe near the bottom of the container with a heat insulating structure that blocks heat conduction from the container, and the communicating pipe has a A temperature switch with a predetermined operating temperature is installed to detect the water temperature inside the pipe.

The present invention is characterized in that a combination of the temperature switch and an indicator lamp can indicate that the water level in the container has decreased.

In other words, the water level alarm device according to the present invention is characterized in that the temperature switch acts to detect the water level, and uses a normally closed type (or normally open type) as the temperature switch, and uses an indicator lamp for these. By combining them in series or parallel, the water level drop is indicated by the closing operation of the temperature switch in the case of series, and by the opening operation of the temperature switch in the case of parallel.

(Embodiment) FIG. 1 shows an embodiment of the present invention, which is an example applied to an electric heat-retaining pot. This electric thermal insulation kit is.

, a vacuum insulation layer is formed between the inner container 1 and the outer container 2. The inner container 1 is provided with a transparent communication pipe 3 that communicates with the upper and lower parts of the inner container 1, and the water level in this communication pipe 3 is controlled by the outer container 2.
It is possible to visually see it through. At the bottom of the inner container 1 is a heating temperature switch 4 that energizes a heater (not shown) until the water temperature in the container 1 reaches a set value after the power switch is turned on.

A temperature switch 5 for heat retention control is provided to maintain the hot water at a temperature slightly lower than the set value once it has reached the set value. The above configuration is the same as the conventional one.

The present invention is characterized by the structure described below.

A communication pipe 6 is provided near the bottom of the inner container 1 in addition to the communication pipe 3. This communication pipe 6 has a heat insulating structure in which L-shaped pipes 7, 7 made of a thermally insulating material (for example, rubber) are connected to the upper and lower communication holes with the inner container 1, respectively, to block heat conduction from the inner container 1 body. A connecting passage is created, and a straight pipe 8 made of a thermally conductive material (for example, stainless steel, copper, alumina, etc.) is connected between these L-shaped pipes 7, 7. This direct switch 9 is thermally isolated from the inner container 1, so it will not operate due to heat conduction from the inner container 1, but if hot water enters the straight pipe 8 of the communication pipe 6. The temperature of the water, that is, the temperature of the water in the inner container 1 can be detected. Such a temperature switch includes, for example, a combination of a temperature-sensitive magnetic material, a magnet, and a reed switch.

A display 11 (a light emitting diode in the figure) is inserted into a hole at the lower front of the outer container 2 .

The temperature switch 9 and the display 11 are as shown in FIG.
Connected in series to the power supply.

In this way, it is the arthropod that has been exposed to the air, starting from A.

When the water level in the inner container 1 is above A and is not heated, the temperature switch 9 is closed and the indicator 11 lights up, but after the heater is energized, the water temperature exceeds the operating point of the temperature switch 9 and the light goes out in a short time. Furthermore, the water temperature reaches the set temperature after a few minutes.

When the amount of water in the inner container 1 decreases due to the use of hot water and becomes lower than the water level A, the straight pipe 8 does not come into contact with the hot water, so it quickly cools down, and the temperature drops below the operating point of the temperature switch 9 and becomes almost the same as room temperature. Become. This brings the temperature switch 9 into a closed state. Therefore, the 9 indicator 11 lights up to indicate that the amount of water in the inner container 1 has fallen below the water level A. Note that an alarm device such as a buzzer may be connected together with the display device 11.

FIG. 3 shows another example of the connection circuit between the temperature switch 9 and the display 11. That is, a normally open type temperature switch 9 is used and connected in parallel to the two display devices 11.

According to this circuit, as shown in FIG. 1, the water temperature is low immediately after water is supplied to the inner container 1, but when the power switch is turned on and the heater is energized and the water temperature rises, the temperature switch 9 is switched to closed, and the indicator is displayed. 11 is not lit. However, when the water level drops below A in FIG. 1 due to the use of hot water, the temperature switch 9 is opened and the 2nd indicator 11 is released from the short circuit and lights up. In this way, you will be notified of a drop in the water level.

Note that if the power supply to the electric heat-retaining pot is restarted when the amount of water in the inner container 1 is empty or below the water level A, the indicator 11 will not turn off even if the water temperature becomes high.

Heating by the heater continues until the temperature of the inner container 1 itself or the water temperature reaches the operating point of the heating temperature switch 4, but the overheating state does not continue.

In the example, the case of an electric heating pot was explained, but 9
It goes without saying that the present invention is not limited to this and can be applied to various containers. However, the communication pipe 6 may be provided horizontally instead of vertically as in the embodiment.

(Effects of the Invention) As described above, according to the present invention, it is possible to reliably detect and notify that the hot water level is below a certain level using an inexpensive temperature switch.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of an electric heat-retaining pot showing an embodiment of the present invention, and FIGS. 2 and 3 are circuit diagrams showing examples of electric circuits for indicating a drop in water level. 1: Inner container, 2: Outer container, 6: Communication pipe, 9: Temperature switch, 11: Display.

Claims (1)

[Claims] 1. A communicating pipe is provided near the bottom of the container with an insulating structure that blocks heat conduction from the container, and the communicating pipe has a predetermined operating temperature for detecting the water temperature in the communicating pipe. A water level alarm, comprising a temperature switch, and a combination of the temperature switch and an indicator lamp to indicate that the water level in the container has decreased. 2. In the water level alarm according to claim 1,
The water level alarm uses a normally closed type temperature switch, and the temperature switch and the indicator lamp are connected in series to a power source. 3. In the water level alarm according to claim 1,
The water level alarm uses a normally open type temperature switch and connects the temperature switch in parallel to the indicator lamp.