Method of removing malleable cores from metallic tubular members

Claim 1

IN A PROCESS OF MAKING ELONGATED METAL CANNULAE INCLUDING THE STEPS OF PROVIDING A LENGTH OF METAL TUBING FORMED ABOUT A SMALL DIAMETER MALLEABLE METAL CORE HAVINGAN EXPOSED SURFACE AREA SUBSTANTIALLY LESS THAN SAID TUBING WITHIN WHICH SAID CORE IS DISPOSED AND HAVING DIFFERENT CHEMICAL PROPERTIES FROM THAT OF THE SAID TUBING, AND REMOVING SAID METAL CORE FROM SAID TUBING BY CHEMICALLY TREATING SAID TUBING AND CORE WITH A CORROSIVE SOLITION CAUSING A GASEOUS REACTION PRODUCT HAVING LIMITED SOLUBILITY IN SAID SOLUTION TO BE FORMED WITHIN SAID TUBING WITH SAID GASEOUS REACTION PRODUCT TENDING TO REMAIN WITHIN SAID CORROSIVE SOLUTION AND SAID METAL CORE, THE IMPROVEMENT COMPRISING; IMMERSING A PLURALITY OF SAID ELONGATED METAL CANNULAE EACH HAVING A MALLEABLE METAL CORE IN A CORROSIVE SOLUTION FOR SAID METAL CORE WITHIN A PRESSURE CHAMBER AND HEATING SAID CORROSIVE SOLUTION IN SAID CHAMBER, EFFECTING WITHIN SAID CHAMBER PERIODIC VARIATIONS IN PRESSURE BY CLOSING SAID CHAMBER AGAINST CONTACT WITH THE SURROUNDING ATMOSPHERE, CONNECTING THE INTERIOR OF SAID CHAMBER WITH A SOURCE OF SUPER-ATMOSPHERIC PRESSURE THROUGH A PRESSURE REGULATING MEANS TO PROVIDE WITHIN THE INTERIOR OF SAID CHAMBER A PREDETERMINED SUPERATMOSPHERIC PRESSURE AND MAINTAINING SAID PREDETERMINED SUPER-ATMOSPHERIC PRESSURE WITHIN SAID CHAMBER FOR A PREDETERMINED PERIOD, DISCONNECTING THE INTERIOR OF SAID CHAMBER FROM SAID SOURCE OF SUPER-ATMOSPHERIC PRESSURE WHEREUPON THE PRESSURE IN SAID CHAMBER RETURNS TO NORMAL ATMOSPHERIC PRESSURE AND REMAINS AT NORMAL ATMOSPHERIC PRESSURE UNTIL A SUPER-ATMOSPHERIC PRESSSURE IS AGAIN APPLIED, AND PERIODICALLY CONVEYING FROM SAID CHAMBER WHILE SAID CHAMBER REMAINS AT NORMAL ATMOSPHERIC PRESSURE AN ACCUMULATION OF GASES FORMED THEREIN, AND SUCCESSIVELY REPEATING SAID VARIATIONS IN PRESSURE WITH INTERMITTENT REMOVAL OF ACCUMULATION OF SAID GASES; THEREBY EFFECTING REMOVAL OF THE METAL CORE FROM AN ELONGATED LENGTH OF METAL TUBING AT AN ACCELERATED RATE TO PROVIDE A SMALL DIAMTER PASSAGE THROUGH SAID ELONGATED METAL TUBING.