Double cannula is to drawing screw rod device

The utility model discloses a double cannula is to drawing screw rod device, include drawing screw rod, first sleeve pipe, second sleeve pipe and two airtight circles of stereotyping, wherein, intraductal to drawing the screw rod to set up in first cover, first sleeve pipe sets up in the second cover intraductally, and first sheathed tube length is greater than second sheathed tube length, the airtight circle of stereotyping equals second sheathed tube external diameter including the airtight circle and the base that interconnect, the internal diameter of airtight circle, and just second sleeve pipe both ends are arranged in to airtight snare, and the base is the ring form, and middle hollow position sets up airtight circle, the ring plane and template contact of base during the use, and the second sleeve pipe passes the wall body. The utility model discloses a simple process, feasibility are strong, can show improvement concrete appearance quality, gain good economic benefits, especially have fine applicatio