On-site fabrication of elbows from pre-made bent pipes
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On long-distance pipelines, bends with random angles such as 7 degrees, 16 degrees, 32 degrees, 31 degrees, and so on are often encountered. I’ve seen pipefitters cut bends of smaller angles from 90-degree bends of 5D or 10D sizes. Does anyone know how this is done? It can be accomplished simply by using a tape measure for cutting
This post was last edited by Sammy_Wang on 2015-9-21 at 16:13. Knowing the radius and angle to calculate the length of an arc of a sector – is that what it means? That is, the inner and outer arc lengths of the pipe near the center of the bending radius. Alternatively, and more simply, divide the curved pipe into 90 equal segments; each segment represents 1 degree. To find out how many degrees there are, measure the length of that many segments.
More or less. I think he just used the radius and angle to calculate the arc length, but there are straight sections at the ends as well as pipes with a diameter of 219. Is the radius referred to as the center of the pipe at the elbow, or rather to the inner or outer arc?
This d, to the pipeline centerline, is neither the inner arc nor the outer arc. For the straight pipe section, was its length indicated when it arrived? Alternatively, use a ruler to press it against; the point where gaps begin to appear is considered the starting point of the arc. Even if there is a slight deviation in the material cutting, it can be adjusted by trimming the edges during pipe alignment.
On-site construction won’t be that precise; generally, it’s not necessary either – adjustments can be made during assembly. I remember that when I went to the site for the first time, the first problem that needed to be solved was that the installation dimensions did not match. When I went to the site, it seemed to me that the position of this pipe was incorrect – it was at least over 1 meter off. It was only after the construction team carefully examined the drawings that they realized it was their mistake in determining the dimensions: L
Well, it seems you do understand. By the way, he calculated the corresponding outer arc length using angles, then used a tape measure to mark the line for cutting. I noticed that the inner and outer arcs of the cut elbow weren’t of equal length; how did he determine the length of the inner arc?
Not entirely clear: 1. Calculate the inner arc length by placing a tape measure against the inner curved side of the pipe； 2. Calculate the bending radius by using a tape measure to measure right above the bent pipe.
Maybe just wrap a measuring tape around that point on the outer arc, and that’s it
With experienced craftsmen on site, nothing is needed – the cutting is accurate right from the start