PLUG MEMBER AND ATTACHMENT/DETACHMENT DEVICE FOR THE SAME

摘要

A plug member can be mounted to the end of a pipe and removed therefrom by automated operation. A mounting and dismounting device 21 for mounting and dismounting a plug member 11 with respect to an oil country tubular good P. The plug member 11 comprises an outer tube 12 having seal portions 16a and 16b and a circumferential groove 12a, a shuttle 13, a cap 14, and a shuttle biasing spring 15 secured to the cap 14 and the shuttle 13. The mounting and dismounting device 21 comprises a tubular holding body 22, a rod 23 which has a conical end portion 23a and which is disposed so as to move inside the tubular holding body 22, and moving means 24 and 25 which allow the tubular holding body 22 and the rod 23 to independently move. The tubular holding body 22 has ball-receiving holes 22a into which fit balls 26 which engage with the circumferential groove 12a. The tubular holding body 22 is inserted into the outer tube 12 through the proximal end of the tube so as to make its tip contact the end surface of the shuttle on the side of the proximal end, and the rod 23 is moved relative to the tubular holding body 22 so as to contact its end portion 23a with the balls 26 to make the balls 26 engage with the circumferential groove 12a, thereby connecting the tubular holding body 22 and the outer tube 12. The rod is moved relative to the tubular holding body 22 to retract the end portion 23a, thereby releasing the connection between the tubular holding body 22 and the outer tube 12.