Finned tubing

Claim 1

FINNED TUBING CONSTRUCTION INCLUDING A METAL TUBE HAVING AN OUTER SURFACE, GENERALLY L-SHAPED CROSS-SECTION STRIP-LIKE METAL FIN MEANS HAVING SUBSTANTIALLY CONTINUOUS FIN PORTIONS AND CONNECTED FOOT PORTIONS, THE FIN MEANS FOOT PORTIONS HAVING CONNECTED ENDS AT THE FIN PORTIONS AND FREE ENDS SPACED FROM THE FIN PORTIONS, THE FIN MEANS BEING POSITIONED LENGTHWISE OF THE FIN PORTIONS ON THE TUBE OUTER SURFACE WITH THE FOOT PORTIONS EXTENDING OVER AT LEAST A PART OF SAID TUBE OUTER SURFACE AND THE FIN PORTIONS EXTENDING FROM SAID TUBE OUTER SURFACE, THE TUBE HAVING GROOVE MEANS EXTENDING INWARDLY FROM SAID TUBE OUTER SURFACE AND OPENING OUTWARDLY AT SAID TUBE OUTER SURFACE, SAID GROOVE MEANS BEING FORMED SO THAT CERTAIN PORTIONS OF THE TUBE METAL OUTWARDLY OVERLIE PARTS OF SAID GROOVE MEANS SUBSTANTIALLY THROUGHOUT THE EXTENT OF SAID GROOVE MEANS, THE GROOVE MEANS BEING LOCATED UNDERLYING A PART OF SAID FIN MEANS FOOT PORTIONS INTERMEDIATE SAID FIN PORTIONS AND SAID FOOT PORTION FREE ENDS AND EXTENDING SUBSTANTIALLY THROUGHOUT THE LENGTH OF SAID FIN MEANS FIN PORTIONS, AND PARTS OF THE FIN MEANS FOOT PORTIONS BEING EMBEDDED IN THE TUBE GROOVE MEANS AT LEAST PARTIALLY INWARDLY UNDERLYING SAID TUBE METAL CERTAIN PORTIONS SO THAT SAID FIN MEANS FOOT PORTIONS ARE INTERLOCKED WITH THE TUBE WITHIN SAID TUBE GROOVE MEANS SUBSTANTIALLY THROUGHOUT THE LENGTH OF THE FIN PORTIONS FORMING A METAL-TO-METAL INTERLOCK AND HEAT TRANSFER BOND BETWEEN THE TUBE METAL AND FIN MEANS METAL RESISTING SEPARATION DESPITE SUBJECTION TO SEVERE TEMPERATURE GRADIENTS.