JPH027399Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Purpose of the Invention" (Field of Industrial Application) The present invention relates to an overheating prevention device that is attached to a hot water tank of a hot water washing device, an electric water heater, or the like.

(Prior Art) FIG. 3 is a partially cutaway perspective view showing a hot water washing device 3 installed in a Western-style toilet bowl 2 (indicated by a two-dot chain line). The hot water washing device 3 is a device in which a washing nozzle 4 extends into the toilet bowl by operating a switch 2b arranged on the side of the toilet seat 2a, and sprays warm water onto the anus and the like after defecating. . An electric heater (not shown) is provided in the hot water tank 1 of the hot water washing device 3, and is used to heat and keep the stored water warm.

By the way, since the water stored in the tank is sprayed directly onto the human body as mentioned above, it is extremely dangerous for the water to rise above the specified temperature (approximately 40°C) during storage, so preventive measures must be taken at all costs. must be. In the conventional hot water tank 1, a liquid expansion type temperature control thermostat 5 is installed in the tank to control the supply of electricity to the heater intermittently, thereby stabilizing the stored water temperature (particularly preventing the temperature from rising to an abnormally high temperature). ) was planned. In addition, in case the temperature control thermostat 5 breaks down, a bimetallic safety thermostat 6 and a temperature fuse 7 are connected in series and interposed in the heater circuit. Double safety measures were taken to disconnect the circuit. Furthermore, a float switch (not shown) may be provided to prevent the hot water tank 1 from running dry when all of the temperature control thermostat 5, safety thermostat 6, and temperature fuse 7 are out of order. It was hot. As described above, the conventional hot water tank 1 is equipped with various safety devices in multiple layers.

(Problems to be Solved by the Invention) In the conventional hot water tank 1, safety devices other than the temperature control thermostat 5 were attached to the outside of the tank for waterproofing purposes. Therefore, these safety devices have the disadvantage of being easily influenced by the environmental temperature outside the tank. That is, especially in cold regions, when the temperature control thermostat 5 malfunctions, it cannot necessarily be said that the safety thermostat 6 and the temperature fuse 7 will function accurately. In this case, no matter how many layers of safety equipment are installed, it will only serve as a supplementary measure.

The present invention was developed in view of the above-mentioned circumstances, and when the waterproofing temperature inside the hot water tank exceeds a predetermined temperature, the inside of the hot water tank is reliably sealed without being affected by the environmental temperature outside the tank. The object of the present invention is to provide a new and safe overheating prevention device (hereinafter referred to as the proposed device) that can stop the power supply to the heater.

"Structure of the invention" (Means for solving the problem) The gist of the proposed device is an overheating prevention device attached to a hot water tank, which works in conjunction with a float that moves up and down in response to changes in the water level of the stored water. It is equipped with a float switch for preventing dry firing that interrupts the supply of electricity to the heater, and a shape memory alloy part that recovers its shape due to the abnormally high temperature of the atmosphere or stored water in the tank and forcibly lowers the float of the float switch against buoyancy. It consists of a floating device.

(Function) The floating device includes a shape memory alloy part.
In other words, when the atmospheric temperature or storage water temperature in the tank rises to a high temperature higher than the set value, the overall shape of the shape memory alloy part deforms (shape recovery behavior).
do. By deforming the shape memory alloy part, the floating device forcibly lowers the float of the float switch, which is originally used to prevent dry firing. Therefore,
Temporarily, even if the water stored in the tank is full, if the atmospheric temperature inside the tank or the stored water temperature reaches an abnormally high temperature, the float of the float switch will be lifted by the floating device regardless of the environmental temperature surrounding the hot water tank. It resists buoyancy and is submerged in water.
Therefore, since the power to the heater is immediately cut off by the float switch, the water stored in the tank will not be overheated. In addition, even if the float of the float switch gets caught on the tank ceiling wall and cannot be lowered, the deformation of the float lowering device ensures that it can be forced down, making it extremely safe. It is.

(Example) The present invention will be described below based on drawings showing examples thereof.

FIG. 1 is a side sectional view showing a hot water tank 1 equipped with the present device. The proposed device consists of a float switch 8 and a floating device 9.

The float switch 8 is vertically installed on the tank ceiling wall 1a, and consists of a track shaft portion 8a and a float 8b that can be raised and lowered along the track shaft portion 8a. The float switch 8 is used to prevent the hot water tank 1 from running dry, and operates in conjunction with the lowering of the float 8b when the water level in the tank falls below a predetermined water level. (not shown).

The floating device 9 is inserted through the track shaft portion 8a of the float switch 8, and placed on the float 8b. The floating and descending tool 9 is made up of two bowl-shaped pieces 9a, 9a that are connected so as to face each other, and its outer shape is similar to an abacus ball.
The bowl-shaped piece 9a is entirely made of a shape memory alloy. The composition of the shape memory alloy is set so that it recovers its shape when the atmospheric temperature inside the tank increases to exceed a predetermined temperature. Therefore, the bowl-shaped pieces 9a, 9a like abacus beads
After the combined shape is restored, it deforms like a long lantern, as shown in FIG. 2, and its overall height increases. For this reason, the float 8 of the float switch 8
Even if the inside of the tank is full of water, the item b can be submerged into the stored water against its buoyancy.

Shape memory alloys have the characteristics of two types: those that recover their shape at a certain temperature and then return to their original shape when the temperature drops below a certain level, so-called bidirectional ones, and those that recover their original shape even when the temperature falls below a certain level. There are some that do not return to their shape, so-called unidirectional ones.
In the present device, it is preferable to use one that exhibits unidirectional characteristics. The reason for this is that once the floating device 9 recovers its shape, maintenance (replacement of the floating device) by a specialist is necessary, and the cause of the accident will be investigated during maintenance. Therefore, future accidents due to the same cause can be prevented from occurring. However, the present invention is not limited in this respect, and a shape memory alloy exhibiting bidirectional properties may also be used.

(Study of Alternative Embodiments) Only a portion of the floating device may be formed of a shape memory alloy. Further, the outer shape of the floating device may be arbitrary, such as a coil spring shape, a pantograph shape, or a solid three-dimensional shape. For example, although not shown in the drawings, the floating device is formed into a shape similar to an upright pincushion, and the upper and lower end brim-shaped disk portions are made of general metal material, resin material, etc., and only the central body portion is formed. It is also possible to use the shape memory alloy part as a shape memory alloy part, and the shaft hole provided in the center of the body part to be used as an insertion hole for the raceway shaft part of the float switch. Of course, the shape memory alloy part in this case must be designed so that the shape recovery behavior is such that the body increases in the longitudinal direction. Alternatively, the floating device may be attached to the bottom wall of the tank, etc., and the float of the float switch may be pulled down by directly sensing the temperature of the stored water. Furthermore, the float switch may have a structure in which the float is supported in a lever-like manner through the swing point, such as a ball tap in a low tank, and the float lowering device may be installed in the middle of the float lever so as to face downward. . In this way, the configuration and shape of the present device can be changed as appropriate depending on the mode of implementation.

"Effect of the invention" As is clear from the above explanation, according to the overheating prevention device for a hot water tank according to the invention, the temperature of the water stored in the hot water tank will not rise to a high temperature higher than a predetermined temperature. , there is no danger of burns or other dangers to users of hot water cleaning equipment, etc. Furthermore, since the floating device is installed inside the tank and is not affected by the environmental temperature surrounding the tank, there is no risk of malfunction. Furthermore, even if the float of the float switch gets caught on the tank ceiling wall etc. for some reason, if the atmospheric temperature inside the tank rises, the float and lowering device can assist the float switch. Since it will now be in operation and will also act as a safety device to prevent dry firing, you can have extremely high confidence in its safety. Furthermore, with the proposed device, conventional safety thermostats and temperature fuses can also be replaced.
This will provide value as a dedicated protection device for electrical circuits. In addition, some hot water washing devices and electric water heaters are equipped with a float switch to prevent dry heating, but for such devices, it is only necessary to add a floating device. It has many excellent advantages, such as being able to implement the proposed device easily and at extremely low cost even in an existing hot water tank.

[Brief explanation of drawings]

Figure 1 is a side sectional view showing a hot water tank equipped with the proposed device, Figure 2 is a side sectional view showing the operating status of the proposed device, and Figure 3 is a hot water washing device installed in a Western-style toilet (conventional hot water tank). ) is a perspective view showing the. 1...Hot water tank, 3...Hot water cleaning device, 8...
...Float switch, 8b...Float, 9...Float descending device.

Claims (1)

[Scope of utility model registration request] This is an overheating prevention device installed in a hot water tank, and includes a float switch that works with a float that rises and lowers in response to changes in the water level of the stored water to cut off power to the heater, and a float switch to prevent overheating. 1. An overheating prevention device for a hot water tank, comprising a float lowering device comprising a shape memory alloy part that recovers its shape and forcibly lowers the float of the float switch against buoyancy.