| 摘要 |
<p>1,220,856. Pipe joints. MANNESMANN A.G. 11 April, 1968 [28 April, 1967], No. 17553/68. Heading F2G. A gastight joint between pipes, e.g. for drilling, consists of a tapered thread 3 and an abutment between the concave conical end 5 of the inner pipe and a convex mating shoulder 5 in the outer pipe which produces an expanding force 10 on the inner pipe tending to counteract the compressive force 9 due to the thread. Preferably but not necessarily, the angle a of the cone is larger than the angle of friction of the pipe material. Between the thread and the abutment there is a spherical seal head portion 4 which mates with a tapered surface 8 in the outer pipe. Due to the balance between forces 9 and 10 the sealing pressure at point 12 is adequate without producing fretting.</p> |
