Patent ID: 9670741
Date: 2017-06-06
CPC Classifications: E21B,F16L

Claim:
1. A threaded connection having a straight central axis, the connection comprising: a pin having an external pin seal surface and an internal pin seal surface, the external and internal pin seal surfaces separated by a run-in pin thread portion, a perfect pin thread portion, and a run-out pin thread portion, each pin thread portion having a plurality of pin threads, each pin thread having a root, a crest, a stab flank, and a load flank, the depth of each pin thread determined by the distance between the root and the crest, and the width of each pin thread determined by the distance between the stab flank and the load flank, wherein each stab flank is angled between 9° and 20° relative to a plane perpendicular to the straight central axis and toward the external pin seal surface, wherein each load flank is angled between −4° to −9° relative to the plane perpendicular to the straight central axis and toward the external pin seal surface, and wherein for each pin thread an absolute value of the angle of the stab flank is greater than an absolute value of the angle of the load flank; a box having an internal box seal surface and an external box seal surface, the external and internal box seal surfaces separated by a run-in box thread portion, a perfect box thread portion, and a run-out box thread portion, each box thread portion having a plurality of box threads, each box thread having a root, a crest, a stab flank, and a load flank, the depth of each box thread determined by the distance between the root and the crest, and the width between each box thread determined by the distance between the stab flank and the load flank of adjacent box threads; the pin threads and the box threads arranged so that when the connection is fully made up, the threads of the run-in pin thread portion engage the threads of the run-out box thread portion, the threads of the perfect pin thread portion engage the threads of the perfect box thread portion, the threads of the run-out box thread portion engage the threads of the run-in pin thread portion, the external pin seal surface sealingly engages the external box seal surface, and the internal pin seal surface sealingly engages the internal box seal surface; and the width of the pin threads is slightly greater than the width between corresponding box threads, so that as the pin threads engage with the box threads, an interference fit is created between the pin threads and the box threads to limit axial movement in the connection under tension and compression and reduce deformation of the seals during full compression.