APPARATUS FOR ADJUSTING SHAPE MEMORY ALLOY TRANSITION TEMPERATURES TO TRACK SLOWLY CHANGING AMBIENT TEMPERATURE

摘要

A valve actuator, valve, and method of actuation of a valve are disclosed. The valve actuator includes a shape memory alloy element attachable to a valve body, capable of use with a valve to cause movement of the valve between first and second positions at a predetermined temperature and responsive to at least a threshold amount of temperature change of the shape memory alloy element. The valve actuator further includes an expansion element attached to the shape memory alloy element, the expansion element responsive to temperature changes at a rate lower than a rate of change of temperature indicative of a valve leak, the expansion element adjusting tension on the shape memory alloy element, thereby changing the predetermined temperature.

主权项

1. A valve actuator comprising:
a shape memory alloy element attachable to a valve body, the shape memory alloy element capable of use with a valve to cause movement of the valve between first and second positions at a predetermined temperature and responsive to at least a threshold amount of temperature change of the shape memory alloy element; and an expansion element attached to the shape memory alloy element, the expansion element responsive to temperature changes at a rate lower than a rate of change of temperature indicative of a valve leak, the expansion element adjusting tension on the shape memory alloy element, thereby changing the predetermined temperature.