Apparatus for coating tubes

Claim 1

APPARATUS FOR APPLYING A COATING TO THE INTERIOR OF A TUBE COMPRISING, IN COMBINATION, (A) A FIRST CONDUIT FOR LIQUID SOLIDIFIABLE COATING MATERIAL HAVING (1) A CONNECTION TO A SOURCE OF LIQUIFIED COATING MATERIAL, (2) AND AN OPEN END PORTION, (B) A SECOND CONDUIT FOR GAS POSITIONED WITHIN SAID FIRST CONDUIT, SAID SECOND CONDUIT HAVING (1) CENTERING MEANS THEREON FOR MAINTAINING SAID SECOND CONDUIT COAXIAL WITH SAID FIRST CONDUIT, (2) A CONNECTION TO A SOURCE OF GAS, (3) AND AN OPEN END PORTION, (C) SAID END PORTIONS OF SAID CONDUITS FORMING AN ANNULAR EXTRUSION ORIFICE THEREBETWEEN FOR THE PASSAGE OF COATING LIQUID AROUND THE OPEN END OF THE SECOND CONDUIT, (D) SUPPORT MEANS POSITIONING THE FIRST CONDUIT RELATIVE TO THE TUBE (1) WITH ASSOCIATED MEANS FOR ADHERINGLY APPLYING A BUBBLE OF THE COATING MATERIAL EXTRUDED THROUGH THE ORIFICE FIRST TO THE INTERIOR OF ONE END OF THE TUBE AND THEN PROGRESSIVELY DOWN THE REMAINDER OF THE INTERIOR SURFACE OF THE TUBE WHILE LIQUID COATING MATERIAL IS CONTINUOUSLY EXTRUDED THROUGH THE ORIFICE TO EXPAND THE BUBBLE ALONG THE LENGTH OF THE TUBE (E) AND CONTROL MEANS ADJUSTABLY CONNECTING THE CONDUITS FOR VARYING THE WIDTH OF THE ANNULAR EXTRUSION ORIFICE BETWEEN THE ENDS OF THE CONDUITS.