Device and method for strengthening thin-walled straight pipe

A device for strengthening a straight pipe, comprising:

• a first positioning mold;
• a second positioning mold;
• at least two split molds;
• a rounding mold;
• and
• a sealing assembly;
• wherein the first positioning mold and the second positioning mold are coaxially arranged and are respectively provided with a first through hole and a second through hole configured to allow a pipe to pass through;
• the at least two split molds are arranged between the first positioning mold and the second positioning mold and slidable with respect to the first positioning mold and the second positioning mold along a direction which is perpendicular to an axis of the first positioning mold;
• adjacent split molds of the at least two split molds abut against each other to form a ring;
• a side of each of the at least two split molds facing the axis of the first positioning mold has a convex surface;
• a minimum inner diameter of the ring formed by the at least two split molds is smaller than an inner diameter of the first positioning mold;
• the rounding mold is arranged downstream of the at least two split molds along a transportation direction of the pipe, and abuts against the second positioning mold;
• the rounding mold is provided with a third through hole configured to allow the pipe to pass through;
• an inner diameter of the rounding mold matches with an outer diameter of the pipe;
• the sealing assembly comprises a first sealing ring, a second sealing ring and a third sealing ring;
• the first sealing ring, the second sealing ring and the third sealing ring are able to enter an inner cavity of the pipe;
• the first sealing ring and the second sealing ring form a first cavity with an inner wall of the pipe;
• the second sealing ring and the third sealing ring form a second cavity with the inner wall of the pipe;
• and the first cavity is communicated with an external environment, and the second cavity is communicated with the external environment.