Shape memory alloy lifting tubes and shape memory alloy actuators including the same

A shape memory alloy (SMA) actuator, comprising:

• an SMA lifting tube that includes and extends between a first end and a second end and that is configured to be in thermal communication with a process fluid during operative use of the SMA actuator;
• wherein the SMA actuator is configured to assume a conformation among a plurality of conformations defined between and including a first conformation and a second conformation;
• wherein the conformation of the SMA actuator is based, at least in part, on a temperature of the process fluid that is in thermal communication with the SMA lifting tube during operative use of the SMA actuator;
• wherein the SMA lifting tube is configured such that the second end translates relative to the first end at least partially along a lateral direction that is at least substantially perpendicular to at least a portion of the SMA lifting tube between the first end and the second end as the SMA actuator transitions between the first conformation and the second conformation;
• wherein one of the first end and the second end is an upstream end of the SMA lifting tube;
• wherein the other of the first end and the second end is a downstream end of the SMA lifting tube;
• wherein the SMA actuator is configured such that the process fluid flows through the SMA lifting tube from the upstream end to the downstream end during operative use of the SMA actuator;
• wherein the SMA lifting tube includes an SMA coil;
• wherein at least 75% of the SMA coil extends within a coil plane when the SMA actuator is in one of the first conformation and the second conformation;
• and wherein the lateral direction is at least substantially perpendicular to the coil plane.