JPH0624111Y2 - Level switch - Google Patents

Description

[Detailed Description of the Invention] Industrial field of application The present invention relates to a water level switch installed in a hot water tank used for a water heater, a washing type hot water valve seat, etc. It also prevents abnormal heating of hot water.

Conventional technology Conventionally, water is poured into the tank, and after reaching a certain level, the heater inside the tank is turned on to turn it into warm water. If the water level drops when the hot water is taken out, the level switch operates and the power is turned off. This type of level switch has a built-in magnetic switch at a fixed position in the cylindrical shaft, and a float having magnetic force is provided on the outer periphery of the level switch, and the magnetic switch in the cylindrical shaft is activated by the vertical movement of the float. It was

Problems to be Solved by the Invention According to the above configuration, the upward movement of the float is caused by the buoyancy of the float, and the downward movement is caused by the weight of the float. The float uses a fairly light material to extract buoyancy. Therefore, even if a small amount of foreign matter adheres between the cylindrical shaft and the float, the float cannot move up and down. Especially when the water temperature is kept around 40 ° C, microbial deposits may attach and significantly hinder it. As a result, even if the water level drops, the heater power will remain ON, and the tank and heater will be damaged due to baking or abnormal heating, resulting in a dangerous situation.

Means for Solving the Problems The present invention has been made to prevent the above-mentioned drawbacks. A concave chamber is provided in the center of the float, and a hole is formed in a part of the wall of the concave chamber. That is, a coil panel made of a shape memory alloy is provided in the recessed chamber so as to extend at a predetermined temperature.

Action With the above configuration, when the ambient temperature near the level switch is increased and the temperature rises above the predetermined temperature stored in the shape memory, the coil spring set above the center of the float expands and its repulsion The float is pushed down by force to activate the magnetic switch and turn off the heater power. At this time, the hot water in the concave chamber can be properly captured by the convection movement with the hot water outside through the hole of the concave chamber. Such an action can prevent an abnormal temperature rise.

Embodiment As an embodiment of the present invention, a level switch installed in a hot water tank used for a toilet seat with hot water washing will be described with reference to the drawings. A magnetic switch 2 is built in a fixed position inside a cylindrical shaft 1. This cylindrical shaft 1 is fixed to the upper wall of the water tank using a fixed nut 3 and a movable nut 4. Next, a float 5 that moves up and down along the cylinder axis 1 is attached. A magnet 9 is fixed to the lower part of the float 5, and when it is located above, the magnetic switch 2 is turned on, and when it is located below If it does, turn it off. Further, in the center of the upper portion of the float 5, there are provided a recessed chamber 7 and water passage holes 1 to 4 in which a part of the wall of the recessed chamber is cut into a width of about 3 mm in order to improve the flow of hot water in the recessed chamber 7. Provide it in a place. Inside the recessed chamber 7, there is provided a coil spring 6 centered on the cylindrical shaft 1 and vertically movable with respect to the float 5. The coil spring 6 is a shape memory alloy spring that remembers its shape so as to expand at a predetermined temperature or higher. Finally, in order to prevent the float 5 from coming off, a stopper is attached to the lower end of the cylindrical shaft 1.
Install 10.

The operation is to fill the water tank with water and stop pouring water when the water is full. At that time, the float 5 is located above, the magnetic switch 2 is turned on, the heater is energized to make hot water, and the temperature is kept at 40 ° C. by the temperature controller. If hot water is used for cleaning, the water level drops, but the float 5 also drops at the same time to activate the magnetic switch 2 and turn off the heater power. When the hot water is used up, new water is injected and the water becomes full again, the float 5 rises, and the heater power is turned on. This is repeated.

However, since the temperature of the water in the tank is kept at 40 ° C. here, it is possible that microbial propagation materials are deposited on the surface of the level switch and hinder the float 5 from moving up and down. as a result,
Even if the water level drops, the float 5 does not go down, so the magnetic switch 2 remains in the ON state, and the temperature rises abnormally. When the temperature reaches 55 to 60 ° C., the coil panel 6 made of the shape memory alloy in the recess 7 provided in the upper part of the float 5 transforms from the martensite crystal to the austenite crystal and extends, and at the same time, the repulsive force of the spring increases. . Therefore, the upper end of the coil spring 6 hits the fixed nut 3 and pushes down the float 5 that is being pulled. As a result, the magnetic switch 2 is actuated to turn off the heater power supply and prevent an abnormal temperature rise.

In addition, the recessed chamber 7 is inserted through a water passage hole 8 provided in a part of the wall of the recessed chamber 7.
Since the water inside and outside smoothly moves by convection, the temperature difference inside and outside the recessed chamber 7 is small, so that the magnetic switch 2 can be operated at the temperature at which the coil spring 6 of the memory alloy is deformed.

Effect of the Invention As described above, according to the present invention, the coil spring of the shape memory alloy is kept above the predetermined temperature even if the heater cannot be moved up and down because the foreign matter adheres to the surface of the level switch and the float cannot move up and down. It is possible to prevent the abnormal heating by stretching it, pressing down the float and operating the magnetic switch. Further, since the convection of water inside and outside the recess smoothly occurs through the ventilation hole, the temperature difference is small, and the magnetic switch can be operated at a predetermined temperature at which the coil spring extends, so that a highly safe level switch can be provided.

[Brief description of drawings]

 The drawings are cross-sectional views of the essential parts of the present invention. In the figure 1. … Cylindrical axis, 2. … Magnetic switch, 5. … Float, 6. … Coil springs, 7. … Recessed chamber, 8. ... water holes.

Claims (1)

[Scope of utility model registration request] 1. A float (5) having magnetic force is provided on the outer circumference of a cylindrical shaft (1) containing a magnetic switch (2), and the magnetic switch (2) is operated by moving the float (5) up and down. In the level switch, a recess chamber (7) is provided in the center of the upper part of the float (5), and a water passage hole (8) is provided in the wall of the recess chamber (7).
A coil spring (6) is inserted into the (7) along the outer circumference of the cylindrical shaft (1), and the coil spring (6) is made of a shape memory alloy that recovers to an elongated shape at a predetermined temperature, and the float (5) A level switch that moves up and down together with.