JPH10220706A - Water level abnormality detector for steam generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable quick detection of abnormality in water level by detecting the temperature of heat sent from an electric heater to examine the abnormality in water level from changes in the detected temperature. SOLUTION: A temperature detector 3 detects temperature above an electric heater 2. The temperature detected does not rise above a fixed value while the detector detects only the temperature of water in a heating water tank 1. But when the electric heater 2 overheats as water vanishes surrounding the electric heater 2, the temperature of heat transmitted by radiation rises above the temperature of water. Therefore, when the temperature detected by the temperature detector 3 is higher (for example, 120 deg.C) than the temperature of the water, abnormality in water level is determined to occur and a controller 5 works to stop the electric energization of the electric heater 2. As the temperature detector 3 is installed closer to the upper surface of a heat generator 4, the water level abnormality can be detected even if only the top part of the electric heater 2 is exposed from the surface of water. Thus, the detection of the water level abnormality is possible before the water level falls below the position of the electric heater 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water level abnormality detection device for a steam generator for generating steam by heating water in a heating water tank with an electric heater.

[0002]

2. Description of the Related Art As a steam generator for supplying steam to a steamer or the like, a hole for an electric heater is formed in a side wall of a heated water tank in which water is stored, and a screw is formed so that a heating portion of the electric heater is located in the heated water tank. There is used a steam generator of a type in which an electric heater cut off is screwed and fixed, and water is heated by the electric heater to generate steam. In the case of the steam generator, when the steam is generated, the water level in the heating water tank is reduced. Therefore, the water level is maintained by supplying water according to the water level. When the amount of water in the heating water tank is sufficient and the electric heater is completely submerged, the heat generated by the electric heater is transferred to the water, so that the electric heater does not overheat. If the electric heater is exposed to an abnormal water level above the water surface, i.e., becomes empty, the heat generated by the electric heater does not move to the water but is accumulated in the electric heater, so that the electric heater is overheated and damaged.

[0003] When the water level in the heating water tank becomes abnormal, it is necessary to immediately stop the heating of the electric heater. When the electric heater is overheated and the temperature of the electric heater detected by the overheat detecting device becomes equal to or higher than a predetermined temperature, it is determined that a water level abnormality has occurred and the heating of the electric heater is stopped. Had been By the way, the overheating of the electric heater starts from the upper part of the electric heater which is exposed from the water surface most quickly. When the overheating detecting device is provided at the lower part of the electric heater, the detection becomes slow. Since the electric heater is provided on the surface of the heater and rotates when the electric heater is screwed and fixed, the overheat detecting device cannot be limited to the upper part of the electric heater. Also,
Since the overheat detection device in the case of the above device must operate normally even when the electric heater overheats, which may be extremely high, a special overheat detection device that can perform temperature detection at a high temperature is provided. Had to be used.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a steam generator that heats water with a submerged electric heater, which can quickly detect an abnormal water level and perform temperature measurement in a high temperature range. A special temperature detection device is to provide an unnecessary water level abnormality detection device.

[0005]

SUMMARY OF THE INVENTION In a steam generator having a heated water tank for storing water to be evaporated and an electric heater submerged in the heated water tank, temperature detection for detecting the temperature of heat sent from the electric heater. A device is provided above the electric heater independently of the electric heater, and a water level abnormality is detected by a change in temperature detected by a temperature detecting device.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. The steam generator 4 includes a heating water tank 1 for storing water and generating steam, an electric heater 2 for fixing the lower part of the heating water tank by screwing it from the side of the heating water tank, and a temperature sensing part approaching the upper surface of the electric heater 2. A temperature detecting device 3, an electric heater 2, and a control device 5 that is connected to the temperature detecting device 3 by a signal line and controls energization to the electric heater 2.
Water supply line 6 for supplying water to the heated water tank 1, water supply line 6
It comprises a water supply solenoid valve 7 provided in the middle, a steam line 8 for taking out steam generated in the heating water tank 1, and a steam solenoid valve 9 provided in the middle of the steam line 8, and is connected to the steamer 10 by the steam line 8.

The temperature detecting device 3 is provided separately from the electric heater 2. When the temperature detecting device 3 is attached to the electric heater 2, when the electric heater 2 is fixed by screwing, the temperature detecting device 3 is located below the electric heater 2. However, the temperature detector 3 can always be provided above the electric heater 2 by providing the temperature detector 3 separately. In addition, the temperature detecting device 3 has a temperature of 120 ° C.
A general thermometer can be used as long as it can detect the temperature of the order.

When generating steam, the controller 5 energizes the electric heater 2 and the electric heater 2 generates heat. The heat generated by the electric heater 2 moves to the water surrounding the electric heater 2 and generates steam by heating the water. Since the temperature detector 3 and the electric heater 2 are not in contact with each other, the temperature detected by the temperature detector 3 in this case does not directly receive the heat from the electric heater 2 but detects the temperature of the water being heated. It will be. When the steam solenoid valve 9 was opened, the steam generated in the heating water tank 1 was sent to the steamer 10 through the steam line 8 to heat the food in the steamer 10, and was used to heat the food from the top of the steamer 10. The later exhaust steam is exhausted, and the drain where the steam cools and condenses is drained from the lower part of the steamer 10. When the water level drops due to evaporation of the water in the heated water tank 1, the water supply solenoid valve 7 is opened to supply water through the water supply line 6.

The water level in the heating water tank 1 is controlled so as to be kept constant. However, when the water level is lowered for some reason and the electric heater 2 is exposed on the water surface, the exposed portion of the electric heater 2 from the water surface is reduced. Since there is no water around, the heat generated by the electric heater cannot be transferred to the water. In this case, the cooling by the contacting air is slight, and the heat generated at the exposed portion of the electric heater 2 from the water surface is transmitted through the air by radiation or accumulated inside the electric heater 2. The temperature detecting device 3 detects the temperature above the electric heater 2, and when the electric heater 2 is exposed above the water surface, directly detects the radiant heat from the electric heater 2 instead of the water temperature. Becomes The temperature detected by the temperature detecting device does not rise above a certain temperature while the water temperature in the heating water tank 1 is detected, but when the water around the electric heater 2 runs out and the electric heater 2 is overheated, The temperature of the heat transmitted by the radiation is higher than the temperature of the water. Temperature detector 3
When the temperature detected by the controller becomes higher than the temperature in the case of water (for example, 120 ° C.), it can be determined that the water level is abnormal. Stop energization. Since the temperature detector 3 is provided close to the upper surface of the steam generator 4,
The water level abnormality can be detected even when only the upper part of the electric heater 2 is exposed from the water surface, and the water level abnormality can be detected before the water level drops below the electric heater 2.

[0010]

According to the present invention, it is possible to detect a water level abnormality even when only the upper part of the electric heater is out of the water surface. In addition, since the temperature range detected by the temperature detector is low, there is no need to use a special temperature detector that detects temperature at high temperatures, and water level abnormalities are detected using a general temperature detector such as a bimetal thermometer. can do.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a steam generator according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating water tank 2 Electric heater 3 Temperature detection device 4 Steam generation device 5 Control device 6 Water supply line 7 Water supply solenoid valve 8 Steam line 9 Steam solenoid valve

Claims (1)

[Claims] 1. A heated water tank for storing water to be evaporated,
Detects the temperature of heat sent from an electric heater in a steam generator that has an electric heater submerged in a heated water tank and is connected to a water supply line for supplying water and a steam line for extracting steam in the heated water tank. A water level abnormality detection device for a steam generator, wherein a temperature detection device is provided above the electric heater with a gap from the electric heater.