Heat exchanger for friction stir welding apparatus and associated system and method

A self-reacting friction stir welding system, comprising:

• a self-reacting friction stir welding apparatus, comprising:
• a crown shoulder rotatable relative to a workpiece;
• a pin comprising a stirring section and is coupled to the crown shoulder, is co-rotatable with the crown shoulder, and is translationally moveable relative to the crown shoulder;
• a root shoulder coupled to the pin so that the root shoulder is co-rotatable with the pin and translationally co-moveable with the pin;
• and
• wherein a gap is defined between the crown shoulder and the root shoulder, the gap is equal to a thickness of the workpiece, and the stirring section of the pin is positioned within the gap;
• and
• a heat exchanger, comprising:
• a collar secured to and co-rotatable with the root shoulder, wherein the collar is made of a thermally conductive material and comprises a collar flow inlet, a collar flow outlet, and an internal conduit fluidically coupling the collar flow inlet and the collar flow outlet;
• a rotary union comprising a first rotary-union flow outlet fluidically coupled with the collar flow inlet, a first rotary-union flow inlet fluidically coupled with the collar flow outlet, a second rotary-union flow inlet, and a second rotary-union flow outlet, wherein the rotary union is coupled to the collar such that the rotary union is co-rotatable with the collar;
• and
• a manifold comprising a first manifold flow outlet fluidically coupled with the second rotary-union flow inlet and a first manifold flow inlet fluidically coupled with the second rotary-union flow outlet, wherein the manifold is coupled to the rotary union such that the rotary union is rotatable relative to the manifold.

A method of friction stir welding together parts of a workpiece along a joint between the parts of the workpiece, the method comprising:

• co-rotating, relative to the workpiece, a crown shoulder, a pin coupled to the crown shoulder, a root shoulder coupled to the pin, a collar secured to the root shoulder, and a rotary union coupled with the collar;
• when co-rotating the crown shoulder, the pin, the root shoulder, the collar, and the rotary union, translationally moving the pin, the root shoulder, the collar, the rotary union, and a manifold, coupled with the rotary union, along the joint when the workpiece is positioned within a gap defined between the crown shoulder and the root shoulder;
• when translationally moving the pin, the root shoulder, the collar, the rotary union, and the manifold along the joint, stirring together material of the parts of the workpiece with a stirring portion of the pin located within the gap;
• when stirring together the material, transferring heat from the root shoulder to the collar and from the collar to a fluid flowing through the collar;
• supplying the fluid to the collar via the rotary union and the manifold;
• and
• retrieving the fluid from the collar via the rotary union and the manifold.