The utility model provides a RIC stick sheathed tube falls to bore device, includes tail pipe sealing device and air feeder, tail pipe sealing device includes a metal cap that matees with the tail pipe, rubber circle that chassis that has three evenly distributed's a metal clip and one and tail pipe top section size are mated, and metal clip was taken in the embedding in the recess that the tail pipe was opened chassis presss from both sides tight metal cap through the metal clip on the chassis and seals up the tail pipe with rubber circle on the section of tail pipe top, be equipped with in the metal cap with external communicating air feed passageway, and air feed passageway and tail pipe communicate with each other, air feeder inserts gaseously and gaseous mass flow controller including external, the air feed passageway that air feeder leads to in air through tube and the metal cap communicates with each other, and the gaseous mass flow that control let in is big or small.