Manufacture of seamed metallic tubing

Claim 1

THE PROCESS OF MANUFACTURING A SEAMED METAL TUBE, COMPRISING CLEANING AND CURLING A METAL STRIP TO FORM A TUBE HAVING AN OPEN SLIT THEREIN, MOVING THE SLIT IN ONE DIRECTION PAST A LATERAL SEAM-GUIDING MEMBER IN THE SLIT AND LATERALLY INTO THE BITE FORMED BY CONJUGATE GROOVES IN THE MARGINS OF SQUEEZE ROLLS, SAID ROLLS HAVING AT LEAST ONE PAIR OF LATERAL SHOULDERS FLANKING THEIR GROOVES, THE GUIDING MEMBER DIRECTING THE OPEN SLIT INTO THE GROOVES ADJACENTLY TO SAID SHOULDERS, SQUEEZING THE TUBE WITHIN THE BITE TO FORCE TOGETHER THE EDGES OF THE SLIT TO GREENBOND THEM IN THE GROOVES ADJACENT SAID PAIR OF SHOULDERS, DIRECTING A FLOW OF SCAVENGING PROTECTIVE GAS INTO THE SLIT AT THE POINT AT WHICH ITS EDGES CONTACT ONE ANOTHER IMMEDIATELY BEFORE LATERALLY ENTERING THE BITE, THE GENERAL DIRECTION OF SAID FLOW OF GAS AT SAID POINT BEING OPPOSITE TO THE DIRECTION OF THE MOVEMENT OF THE TUBE TOWARD THE BITE, THEREBY TO SWEEP AWAY FROM THE BITE AND THE CONTACTING EDGES OF THE SLIT ANY CLOUD OF CONTAMINATING GASES DIFFUSING FROM THE METAL OF THE TUBE THAT MIGHT OTHERWISE CONTAMINATE SAID EDGES AS THEY ENGAGE.