Patent ID: 8505981
Filing Date: 2013-08-13
Classification: F16L,F23J

Abstract:
1. A double-walled vent pipe section, comprising: a first cylindrical structure having: said first outer wall having a first coupling feature on a first end of the first cylindrical structure and a second coupling feature on a second end of the first cylindrical structure, a second cylindrical structure having: said second outer wall having a first coupling feature on a first end of the second cylindrical structure and a second coupling feature on a second end of the second cylindrical structure; said first coupling feature of the first cylindrical structure adapted to mate with the second coupling feature on the second end of the second cylindrical structure, and said first inner wall having an annular ridge formed therein at a spaced distance apart from said end of the first inner wall, the annular ridge having a height above the outer cylindrical surface and extending into the first annular region, wherein the first end of the first cylindrical structure including the annular ridge is inserted into the second cylindrical structure so that the outer cylindrical surface mates with the inner cylindrical surface along the first and second lengths and the annular ridge engages with the inner cylindrical surface at a spaced distance apart from the end of the second inner wall within the second length.