JPS5826474Y2 - Safety device for sheathed heater type humidifier - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a humidifier, and more specifically, to a safety device for a sheathed heater type humidifier.

In conventional sheathed heater type humidifiers, in order to prevent combustion due to dry firing, a double safety device such as a thermostat or temperature fuse, etc., is installed by shifting either one of the thermostat or the temperature fuse, or by changing the temperature setting, to prevent abnormalities. The structure was designed to prevent temperature rise during

However, the above-mentioned thermostat is accurate over a considerable temperature range, making it very suitable as a safety device. The reliability is low in adverse environments (such as inside an air conditioner) because the thermostat's performance decreases, so a configuration that automatically returns to 0N is often used, but even if the cause of the thermostat's operation is not resolved, it will return to 0N-
Since it is repeatedly turned off, there are safety and longevity issues.

Also, a device with a large capacity that interrupts the main circuit is extremely expensive and has a large size.

On the other hand, temperature fuses are widely used because they are very cheap and small, but they have the disadvantages of long blowing times (poor sensitivity) and lack of reliability, and they have a large capacity.
It is difficult to use when there is a lot of residual heat.

In addition, reliability can be improved by connecting both the thermostat and the temperature fuse in series so that the temperature fuse blows when the thermostat is short-circuited, or by placing the temperature fuse in the main power circuit so that it operates in the same way. Even if the temperature is increased, it takes time for the temperature fuse to blow, so when the temperature fuse blows, the temperature of each part will rise too high, resulting in safety and safety issues.
There is a problem with the lifespan.

The purpose of this invention is to eliminate the above-mentioned drawbacks.The operating temperature of the sheathed heater overheat prevention thermostat and the melting temperature of the temperature fuse are set to be almost the same, and the thermostat is connected to the control circuit, and the temperature fuse is are inserted into the power supply circuit, and the temperature fuse is arranged at the terminal part of the sheathed heater, and even after the control circuit is turned off by the operation of the thermostat, the residual heat of the sheathed heater is added to the temperature fuse. The present invention provides a safety device for a sheathed heater type humidifier, which is characterized in that it is configured to reliably blow out a temperature fuse.

An embodiment of this invention shown in the drawings will be described in detail below.

Figure 1 is a cross-sectional view of a sheathed heater type humidifier implementing this invention, in which 1 is an evaporation water tank (not shown) to which water is automatically supplied as the amount of water inside decreases, and 2 is a water tank of the water tank. The sheathed heater 4, which is installed in the aquarium via a heat-resistant heater mounting flange 3 attached to the side surface, is connected to the contacts r11. of the sheathed heater and the main power switch relay, as shown in FIG. A temperature fuse 5 connected to the power supply in series with r12 is arranged so as to be in contact with the heater terminal section which is the outside of the flange which is the surface of the heat generating part of the sheathed heater or its vicinity, and as shown in FIG. This thermostat is connected to the control circuit in series with the main power switching relay RL and the humidity controller 6 described above.

Here, the operating temperature and fusing temperature of the thermostat 5 and the temperature fuse 4 are set to almost the same temperature, slightly higher than 100°C, as shown in Figure 3, and the surface temperature of the sheathed heater 2 is constant at about 100°C during normal operation. However, if the water in the evaporation water tank 1 runs out and the water cutoff switch (not shown) (switch that turns off the control circuit in the event of a water cutoff) fails, that is, if it becomes a dry firing state, the surface temperature of the sheath top 220 will return to the above state. (varies depending on current density)
The temperature rises rapidly, and first the thermostat 5 operates and the control circuit turns off.

When this thermostat 5 operates and the control circuit turns off,
Power switch relay RL becomes inoperable and its contacts r1□, r
12 is opened and the power is cut off.

However, the terminal part of the sheathed heater is far away from the heat generating part, and as shown in the temperature curve at the bottom of Figure 3, the temperature rises with a delay due to the residual heat of the sheathed heater, and the slope is gentle, so the temperature rise is small. However, the temperature and time are sufficient to blow the temperature fuse.

Since the temperature fuse 4 is reliably blown out in this manner, when this fuse is replaced, it can be determined that the water cutoff switch is malfunctioning, and the fault in the water cutoff switch attached to the humidifier can be known.

As described above, this invention sets the operating temperature of the sheathed heater overheat prevention thermostat and the melting temperature of the temperature fuse to be almost the same, and connects the thermostat to the control circuit.
Inserting each of the temperature fuses into a power supply circuit, and arranging the temperature fuse at a terminal portion of a sheathed heater,
Even after the control circuit is turned off by the operation of the thermostat, the residual heat from the sheathed heater is applied to the temperature fuse to ensure that the temperature fuse is blown, so the thermostat operates and the power supply circuit is disconnected. After the temperature fuse is heated, the residual heat of the sheathed heater inevitably causes the temperature fuse to melt after a certain period of time, which significantly improves safety reliability.Replacing the fuse also prevents water cutoff switch failure, which is one of the causes of dry firing. Since discovery can also be made, it is very advantageous in terms of maintenance, does not require the use of particularly expensive safety devices, and has advantages such as being able to be miniaturized.

[Brief explanation of the drawing]

Each of the figures shows an embodiment of this invention. Fig. 1 is a cross-sectional view of a sheathed heater type humidifier equipped with a safety device of this invention, Fig. 2 is an electrical wiring diagram of the humidifier, and Fig. 3 is an electrical wiring diagram of the humidifier. It is an explanatory diagram of the operation of the safety device of this invention. 1...Evaporation water tank, 2...Sheathed heater, 3.
...Heater is mounted on flange, 4...Temperature fuse, 5...Thermostat, 6...
・Humidity controller, RL...Power on/off switch, r
lo, r12... Contact.

Claims (1)

[Scope of utility model registration request] The operating temperature of the sheathed heater overheat prevention thermostat is set to be approximately the same as the fusing temperature of the fuse, the thermostat is inserted into the control circuit, the temperature fuse is inserted into the power supply circuit, and the temperature fuse is connected to the terminal section of the sheathed heater. Even after the control circuit is turned off by the operation of the thermostat, the residual heat of the sheathed heater is applied to the temperature fuse to ensure that the temperature fuse is blown out. Safety device for sheathed heater type humidifier.