| 摘要 |
PURPOSE:To obtain an anti-freezing valve by which water can be drained accurately by an automatic manner by providing the body of the valve with an actuator made of shape memory alloy of which the transformation temperature is set to adjacent freezing temperature of liquid. CONSTITUTION:A bias spring 3 presses a valve body 2 in the closing direction thereof while a coiled spring 4 made of a shape memory alloy presses the valve body 2 in the closing direction thereof. When temperature of the coiled spring 4 is higher than the transformation temperature, the spring is elongated to close the valve against the resilient force of the bias spring 3. However, if the temperature of the spring is lower than the transformation temperature, the spring is contracted so that the valve is opened because the resilient force of the bias spring 3 concurs the resilient force of the coiled spring 4. If temperature of liquid is reduced to adjacent point of freezing, the valve is automatically opened so that water deposited inside a pipe can be discharged.
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