供热直埋管道小折角弯管水平投影角度替代空间角度的误差分析

如果把大地看做一个大平面,由于坡度的存在,供热弯管在这个平面上的投影角度与实际的空间角度并不相等。如果按照平面角度选择弯管角度会产生一定的误差,在小折角的情况下这种误差不容忽视。施工时按照施工图给定的坐标和高程开槽安装管道,按照平面角度选择的弯管的一端与直管段精确组对焊接后,由于平面角度与空间角度误差的存在,另一端与直管段的焊接处势必会产生一个单缝焊接小折角。当锚固段供热管道可视为直管段的最大折角为0°和0.1°时,按照平面角度去选择弯管,由于空间角度误差产生的折角处可能会发生疲劳破坏。本文通过推导弯管空间角度的计算公式,计算出不同平面角度的弯管,在不同坡度下的空间角度,并给出了必须考虑空间角度的条件。

Error Analysis of Horizontal Projection Angle Replacing Space Angle for Small Bend Angle Elbow of Direct Buried Heating Pipeline

If the earth is regarded as a large plane, the projection angle of the heating elbow on this plane is not equal to the actual space angle due to the existence of slope.If the elbow angle is chosen according to the plane angle, there will be some errors, which can not be ignored in the case of small bend angle. When installing pipes according to the coordinates and elevation slotted in the construction drawing, one end of the elbow selected according to the plane angle is welded with the straight pipe section accurately. Because of the errors of the plane angle and the space angle, the weld of the other end and the straight pipe section will inevitably produce a fold angle. When the maximum bending angle of the anchored heating pipeline is 0 and 0.1 in the straight section, the bending pipe can be selected according to the plane angle, and fatigue damage may occur at the bending angle caused by the space angle error. In this paper, by deducing the formula for calculating the spatial angle of the elbow, the spatial angle of the elbow with different plane angles and different gradients is calculated, and the conditions that must consider the spatial angle are given.