Automatic temperature and humidity regulation – Mixing fluid of dissimilar temperature – Having oscillating or reciprocating valve
Reexamination Certificate
2000-06-22
2001-11-20
Tapolcai, William E. (Department: 3744)
Automatic temperature and humidity regulation
Mixing fluid of dissimilar temperature
Having oscillating or reciprocating valve
Reexamination Certificate
active
06318638
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a hot and cold water mixing device, and more particularly to a hot and cold water mixing device of a thermostatic type in which a movable valve element is pressed from both sides by a bias spring and a temperature-sensitive spring made of shape memory material.
In addition, the present invention relates to a control mechanism for hot and cold water mixing device which can control in such a manner that, in a low-temperature range where the spring constant of a temperature-sensitive spring made of a shape memory alloy is extremely reduced, a bias spring functions as a member for softening the operation force acting on a valve element for closing the valve after the valve element is seated and that the valve element is biased in a direction of closing a hot water port by a regulating member so that the hot water port can be forcedly closed for discharging only cold water.
DESCRIPTION OF THE RELATED ART
As a hot and cold water mixing device of thermostatic type, a device employing a temperature-sensitive spring made of a shape memory material such as a shape memory alloy is publicly known. As disclosed in Japanese patent application H06-147333, a hot and cold water mixing device of this type comprises a cylindrical valve body in which a cold water valve seat and a hot water valve seat are arranged, a valve element which can reciprocate in an axial direction of the valve body and is allowed to come in contact with the cold water valve seat and the hot water valve seat, a temperature-sensitive spring for biasing the valve element in a direction toward the hot water valve seat, a bias spring for biasing the valve element in a direction toward the cold water valve seat, and a temperature regulating handle for moving the bias spring.
By selectively turning the temperature regulating handle, the bias spring is moved in forward and rearward axial directions so as to vary the force applied by the bias spring biasing the valve element, thereby changing the preset target temperature of water mixture.
That is, the rearward movement of the bias spring reduces the force applied by the bias spring so that the valve element comes closer to the hot water valve seat and moves apart from the cold water valve seat, thereby lowering the preset target temperature. To the contrary, the forward movement of the bias spring increases the force applied by the bias spring so that the valve element moves apart from the hot water valve seat and comes closer to the cold water valve seat, thereby rising the preset target temperature. When the temperature of water mixture becomes different from the preset target temperature due to a variation in the temperature of supplied hot water and/or a fluctuation of the supply pressure of hot water in a state where water mixture of a preset target temperature is discharged, the temperature-sensitive spring expands or contracts to shift the valve element so that the temperature of water mixture is automatically recovered to a preset target temperature.
In the conventional hot and cold water mixing device, the relation between the turning angle of the temperature regulating handle and the travel of the valve element is substantially straight and is represented by a broken line in FIG.
4
. That is, for example, the travel of the valve element per a unit turning angle of the temperature regulating handle is substantially uniform in any of a low-temperature range below 30° C., a medium-temperature range from 30° C. to 50° C., and a high-temperature range above 50° C. The relation between the turning angle of the temperature regulating handle and the temperature of water mixture to be discharged is substantially straight in the overall range from the low-temperature range to the high-temperature range.
In general, a faucet with a hot and cold water mixing device is desired to have a wider indication range for the medium-temperature range from 30° C. to 50° C., as shown in
FIG. 5
a
, allowing the fine control for water mixture in the medium-temperature range from 30° C. to 50° C., particularly, from 35° C. to 45° C. For this, the slope of a line (the slope of the line in
FIG. 4
) representing the relation between the turning angle of the temperature regulating handle and the temperature of water mixture in the medium-temperature range from 30° C. to 50° C. should be gentle. However, to make the slope simply entirely gentle, a signficantly large turning range of the temperature regulating handle is required for allowing the temperature control from the low-temperature range to the high-temperature range. In case of the temperature-regulating handle of a turning-type, the turning range of the handle (C-H: when the handle is at C, only cold water through a cold water supply pipe is discharged, while when the handle is at H, only hot water through a hot water supply pipe is discharged) should be 360° or less (normally, 270° or less). Accordingly, making the slope simply entirely gentle as mentioned above can not be employed actually (because the range C-H should be over 360°). This is the reason why the conventional faucet has a small indication range for the medium-temperature range from 30° C. to 50° C., as shown in
FIG. 5
b.
The present invention is made taking such a technical problem into consideration and a first object of the present invention is therefore to provide a hot and cold water mixing device in which the slope in the medium-temperature range is gentle and the slope in the low-temperature range and the high-temperature range is steep, so that a faucet with this hot and cold water mixing device has a wide indication range for the medium-temperature range.
A control mechanism of the conventional hot and cold water mixing device will be described with reference to
FIG. 20. A
valve casing
801
has an inner cavity
802
passing through the center of the valve casing
801
for forming flow passages, and a hot water port
803
and a cold water port
804
formed in a circumferential wall of the valve casing
801
. A spool valve element
805
is fitted slidably in the axial direction of the valve casing
801
for defining the flow rates of hot water and cold water by controlling the ratio of opening areas of the ports
803
and
804
. The spool valve element
805
comprises a hot water valve element
805
a
and a cold water valve element
805
b
integrally connected and is biased by a temperature-sensitive spring
806
made of a shape memory alloy in a rightward direction and biased by a bias spring
807
in a leftward direction in this figure. The rightward and leftward directions are opposite to each other so that the spool valve element
805
is stopped at a position where the springs
806
and
807
balance with each other. One end of the bias spring
807
is supported by a plug member
808
so that the biasing forces of the springs
806
and
807
can be varied by moving the plug member
808
in the axial direction. According to the varied biasing forces of the springs
806
and
807
, the position of the spool valve element
805
is changed and the flowing rate between hot water and cold water are thus changed, thereby changing the temperature of water mixture.
For instance, in a state that the spool valve element
805
is stopped at a preset position where the springs
806
and
807
balance, the supply pressure of hot water or cold water fluctuates so that the flowing ratio between hot water and cold water relative to the same opening area is varied, changing the temperature of obtained water mixture. The temperature-sensitive spring
806
senses such variation and works. That is, the temperature-sensitive spring
806
works as an automatically temperature regulating function by changing its biasing force corresponding to the temperature of obtained water mixture in such a manner as to move the spool valve element
805
in such a direction of correcting the temperature.
Normally in a hot and cold water mixing device with an automatically temperature regulating function, when only cold water is discharged
Banno Michio
Hashimoto Mamoru
Kawachi Toshio
Inax Corporation
Kanesaka & Takeuchi
Tapolcai William E.
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