Patent ID: 8356792

Claim:
A sub sea actuator, comprising: an actuator housing, an activating element movably arranged between activating and deactivating positions, a return spring supported in the actuator housing to move the activating element into the deactivating position, and at least two SMA elements supported in the housing and comprising a temperature elevator configured to control a temperature of the SMA elements, wherein the SMA elements act on the activating element to move the activating element into the activating position against a force of the return spring as a result of a rise in the temperature of the SMA elements, wherein the SMA elements have an axial extension between a first end and a second end, and wherein the SMA elements comprise a number of individual SMA element members reaching from the first end to the second end, defining between the first end and the second end a number of passages for heated fluid to pass between the individual SMA element members, wherein the SMA elements are arranged to be operated alternately and in opposite directions in order to provide a reciprocal motion to the actuating element, and wherein the activating element comprises a slider journalled for reciprocal motion in an actuator housing, each respective end of the slider being connected to an SMA element effecting displacement of the slider upon release of a locking mechanism, and each respective end of the slider being associated with a locking mechanism comprising a lock release SMA element and a lock return spring.