Automatic temperature and humidity regulation – Thermostatic – In fluid controlled
Patent
1997-05-29
1999-03-09
Tapolcai, William E.
Automatic temperature and humidity regulation
Thermostatic
In fluid controlled
137509, 236101D, 251212, G05D 2302
Patent
active
058789499
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a temperature-actuated valve device for preventing the delivery of hot water having a temperature higher than the optimum temperature of use, for example, in a shower device, and a flow passage switching valve using such temperature-actuated valve device.
BACKGROUND ART
For example, as a shower device in a bath room, there has been generally used a type of shower device with the hot water having an appropriate temperature being sprayed from a shower head connected to a hot and cold water mixing valve by means of a hose. In such shower device, the temperature of sprayed water is set by adjusting the valve opening degree at the cold water side and hot water side of the hot and cold water mixing valve by means of a wide variety of mechanisms.
In the operation of a shower, the case has actually occurred where the temperature of sprayed water becomes higher and lower than the set value due to a sudden change in the supply pressure of the cold water and hot water and some other causes. In this case, since the sprayed water has an extremely high temperature, some danger is involved, and so provision of a temperature-actuated valve is effective, such valve being so constituted that, if the temperature of hot water which flows toward the shower head exceeds a certain level, the supply of such hot water is shut-off.
Such temperature-actuated valve is described, for example, in JPB Hei-3-64751, the outline of which is shown in FIG. 50.
This temperature-actuated valve comprises a valve seat 251 incorporated into the internal flow passage of a body 250, a lift valve type of valve body 252 which is adapted to be brought into a seating engagement with the valve seat 251, and a damper spring 253 and a coil spring 254 made of a shape-memory alloy arranged so as to hold therebetween a shift ring 252a provided on the valve body 252.
The coil spring 254 maintains a contracted shape up to a certain temperature, so that the valve body 252 is maintained in the position where it is shifted downward in the drawing, and the seating surface of the valve body 252 is brought out of engagement with the valve seat 251 to thereby open the flow passage. When the temperature exceeds a certain temperature, the coil spring 254 expands due to its shape-memory property and the valve body 252 is brought into a seating engagement with the valve seat 251 to close the flow passage, so that supply of the hot water having a high temperature is shut-off.
Further, there is another construction described, for example, in JPU Sho-61-41500, in which a valve body is provided in the direction of traversing the section of a flow passage, and a coil-like temperature sensing expansion body made of a shape-memory alloy is linked coaxially to the moving direction of the valve body. When the temperature of hot water passing therethrough exceeds the set temperature (for example, 50 degrees centigrade), the valve body is shifted due to the coil-like temperature sensing expansion body to thereby close the flow passage.
The lift valve type of valve body 252 has a considerably large flow resistance, since the valve is closed in a way to gradually narrow the flow passage between the valve body 252 and the valve seat 251. This requires an elastic reaction force of the coil spring 254 made of a shape-memory alloy to be made large, in order that the coil spring 254 shifts the valve body 252 in the direction of closing the valve body 252.
However, although the elastic reaction force of the coil spring 254 depends on the quality of material and the heat treatment of a wire rod, it is also proportional to the size of the outer diameter of the wire rod and, therefore, in order to drive the valve body 252 of the above-described lift valve type, it is necessary to make the wire rod of the coil spring 254 thick. If the coil spring 254 is made large in this way, an influence on the aspect of cost cannot be ignored because the raw material thereof is an expensive shape-memory alloy.
Moreover, if the outer diameter of the wire rod of t
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Enoki Masatoshi
Kato Tsutomu
Masatake Tetsuo
Matsui Hideyuki
Ooshima Toshiyuki
Piolax Inc.
Tapolcai William E.
Toto Ltd.
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