JPS591350Y2 - Heater overheating prevention structure - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a structure for preventing overheating of a heater in a heating tank in which liquid in a container is heated by a rod-shaped heater disposed at the bottom of the container.

An example of this type of heating tank is a hot water heating case.

This case is used to sell products such as bottled milk in a heated state, especially during the winter.
Structurally, the water filled in the case is heated by a rod-shaped electric heater placed at the bottom of the case, and the water temperature can be maintained at a constant temperature by controlling the power supply to this heater with a water temperature detection thermostat, etc. There is.

In addition, such hot water heating equipment has a means to prevent the water temperature detection thermostat from malfunctioning and the heater from being energized and overheating even though the water has evaporated and the water has not been replenished. This is usually done by installing a thermal switch at the bottom of the case so that the temperature sensing surface is in contact with the water, and the switch is activated when the water evaporates and the temperature exceeds 100°C. This is achieved by cutting off power to the heater during operation.

However, in reality, it is inevitable that a rod-shaped heater will have a gap between it and the bottom of the case, and when the water level drops below the heater part due to evaporation, the heater exposed above the water surface will overheat. Since water still remains in the thermal switch area, the operating temperature may not be reached, and the insulation may deteriorate in the heater until the water evaporates and reaches the operating temperature, or in the worst case There is also a risk that the heater may become punctured.

The present invention attempts to solve these drawbacks with a simple structure.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross-sectional view of a top-opening hot water heating case to which the present invention is applied.

In the figure, a rod-shaped electric heater 2 is disposed at the bottom of a case made up of a heat-insulating box 1, and a net stand 3 for placing milk bottles and the like is installed above the rod-shaped electric heater 2.

4 is a thermal switch that operates to cut off the power to the heater 2 when there is no water at the bottom of the case and the temperature reaches around 100℃, and it is installed so that a part of it is exposed from the bottom of the case so that it comes into contact with the water. Ru.

This case is filled with water up to a predetermined value, and a water temperature detector (not shown) such as a thermostat, which is separate from the thermal switch, controls the supply of electricity to the heater 2 on and off to maintain the predetermined temperature.

By the way, in the present invention, the heater 2 is covered with a wire mesh 5 having a predetermined mesh, and the wire mesh 5 is brought into contact with the bottom surface of the case.

Even if the water level drops below the heater 2, this wire mesh 5 functions to suck up the remaining water to the surface of the heater 2 by capillary action, and as a result, the heater 2 remains exposed until the water in the case disappears. It can prevent continuous empty heating like this.

The wire mesh 5, which is a distant relative of this, preferably has about 150 meshes.

Of course, if the water evaporates and runs out without being replenished, the heater 2 will overheat, but the thermal switch 4 will immediately turn off.
Since the heater 2 operates when the ambient temperature reaches a temperature exceeding 100° C., the power supply to the heater 2 is immediately cut off.

Therefore, even if the water temperature detection thermostat malfunctions and the water in the case disappears due to evaporation, the present invention can prevent the heater 2 from continuing to overheat with a very simple structure. Not only damage caused by the high temperature of the bottom part but also deterioration of the insulation properties of the heater 2 can be avoided.

Of course, the present invention is not limited to the case of structure and application as shown in the drawings, but is applicable to any heating tank.

[Brief explanation of drawings]

FIG. 1 shows a sectional view of a hot water heating case to which the present invention is applied. 1: Insulation box, 2: Heater, 3: Mesh stand, 4: Thermal switch, 5: Wire mesh.

Claims (1)

[Scope of utility model registration request] In a heating tank in which the liquid in the container is heated by a rod-shaped heater disposed at the bottom of the container, the heater is covered with a wire gauze with a small mesh and brought into contact with the bottom of the container, so that the liquid in the container disappears. The heater overheating prevention structure prevents the heater from overheating until the thermal switch installed at the bottom of the container is activated.