Patent ID: 9746110
Date: 2017-08-29
CPC Classifications: E21B,F16L

Claim:
1. A gas-tight pipe screw connection assembly having a longitudinal axis along its length and a normal axis perpendicular to the longitudinal axis, comprising: an inner pipe part having a first part being a first press fit surface, a second part being a first stop surface, and a transition surface extending between the first press fit surface and the first stop surface, and an outer pipe part having an interior wall, an outer collar, a second press fit surface having a first angle relative to the longitudinal axis and extending from a radius away from the first stop surface along the length of the outer pipe part, a second stop surface having a second angle relative to the normal axis and being different from the first angle, and an annular recess in said interior wall having a tapered region with a third angle relative to the longitudinal axis different than the first angle and second angle, the tapered region having a greater diameter extending radially outward into the outer pipe part than the radius, and the tapered region extending from the radius to a smooth, continuous, curved, concave portion, wherein the concave portion extends from the tapered region to the second stop surface, such that the annular recess encircles the longitudinal axis, protrudes outward from the longitudinal axis, and extends radially outward beyond the second press fit surface, wherein, when the outer pipe part is joined with the first inner pipe part and the second inner pipe part, connected by contact-pressing and insert-pressing, to form a connection region, the connection region is established from three regions configured to preserve the seal of the pipe connection for superimposed tension, pressure and, in particular, bending stresses of the pipe string, comprising: wherein the quotient of the length of the transition region to the length of the press fit region is from 0.4 to 1.7, wherein second press fit surface is inclined at a ratio of substantially 1:10 relative to the diameter, wherein the first and second press fit surfaces and/or the first and second stop surfaces feature a surface roughness of between Ra=3.2 μm and Ra=0.4 μm, and wherein the second stop surface is angled from between 10° to 20°, relative to the normal axis.