Abstract: A double wall twist tube is formed from at least two tubular blanks with a smaller tubular blank forming the inner wall and a larger tubular blank forming the outer wall. The smaller tubular blank is located within the larger tubular blank and the tubular blanks are each impressed with at least one indentation near one end. Sleeves are inserted into ends of the smaller tubular blank and a mandrel is inserted through the sleeves. Clamping chuck jaws or other clamping devices are provided on a longitudinally movably non-rotatable tail stock squeeze the indented end of the larger tubular blank, securing it to the indented end of the smaller tubular blank and simultaneously securing the tubular blanks to the tail stock. Clamping chuck jaws or other clamping devices are provided on a rotatable head stock squeeze the opposite end of the larger tubular blank, securing it to the opposite end of the smaller tubular blank and simultaneously securing the tubular blanks to the head stock.

Abstract: An improved heat exchanger tube is provided in which the tube has one or more paralleled integral spirals formed in the tube wall providing on the exterior surface one or more convoluted spiral recesses of selected pitch, and fin members affixed to the spiral tube providing a tube having greatly increased external surface area, per unit of length and a convoluted, laminar flow breaking, interior surface.

Abstract: A header and tube assembly for use in a shell-and-tube type heat exchanger formed of a header plate having a plurality of spaced apart openings therethrough, each opening having a large cross-sectional area in the portion adjacent the header outer surface than the cross-sectional area adjacent the inner surface, a tube received in each of the openings, each tube having an outer end extending at least even with the header outer surface, and a sealer filling each of the openings in the header and surrounding the tube in the openings to thereby secure each tube in a leak-proof arrangement. In one embodiment, each opening in the header is of conical cross-sectional configuration, and in another embodiment, each opening in the header has a smaller cross-sectional portion adjacent the header inner surface dimensioned to snugly receive the tube and a larger cross-sectional portion adjacent the header outer surface to receive the sealer therein.

Abstract: A heat pipe for providing enhanced thermal conductivity for transfering heat from a heat sink, such as the earth, to a separate medium, including an elongated, generally vertical, tube closed at each end and having a heat absorption portion adjacent the lower end and a heat dissipation portion adjacent the upper end, the wall of the tube having an integral spiraled groove therein forming internal spiraled valleys and ridges, a refrigerant within the tube having a liquid and a vapor phase wherein the refrigerant is converted to vapor in the heat absorption portion and the vapor is converted to liquid in the heat dissipation portion, the vapor being free to rise within the interior of the tube, the condensed liquid refrigerant flowing downwardly in the tube interior spiraled valleys.

Abstract: A method of manufacturing a spiral tube including the steps of positioning an elongated mandrel within a tube, grasping the ends of the tube, forming a point of reduced resistance to torsional force in the wall of the tube, rotating one end of the tube while the other end is held stationary to cause the formation of a spiral groove in the tube, the mandrel defining the minimum interior diameter of the spiral tube so formed, and advancing the means grasping the tube towards each other to compensate for the reduction of length of the tube as the spiral groove therein is formed, and maintaining at least the area of the tube at which the spiral groove is being formed at an elevated temperature.

Abstract: An automated apparatus for forming helical corrugations in a cylindrical tube and comprising a tail stock movable in alternate forward and reverse directions, a head stock disposed in spaced relation with respect to the tail stock whereby the tube may be supported therebetween in a manner for rotating one end of the tube about its own longitudinal axis while holding the opposite end against rotation for twisting the wall of the tube to form the corrugations, a sensor device for detecting the progression of the corrugations along the length of the tube whereby forward movement of the tail stock and forward rotation of the head stock is stopped in accordance with a predetermined position in the twisting operation and the tail stock and head stock are actuated in reverse directions for a controlled unwinding and stretching of the twisted tube, a first sensor device responsive to the reverse movement of the tail stock for releasing the engagement of the twisted tube for permitting removal of the tube from the app