弯头或弯头有各种半径，可以方便地改变方向，用管道标称尺寸表示，单位为英寸。弯头或弯头有三个半径。一个长半径弯头（半径= 1.5D）在需要将摩擦流体压力损失降至最低的情况下最常使用，有足够的空间和体积以允许更宽的转弯并产生更小的压降。
Elbows or elbows have various radii and can be easily oriented, expressed in inches by the nominal size of the pipe. Elbows or elbows have three radii. A long radius elbow (radius = 1.5D) is most often used when the friction fluid pressure loss needs to be minimized, with enough space and volume to allow wider turns and produce a smaller pressure drop.
湾 长半径弯头（半径> 1.5D）有时用于输送高粘度流体的特定应用，如泥浆，低聚物等。对于半径超过1.5D的管道弯曲通常使用，这些可以制成任何半径。但是，3D和5D弯管是最常用的弯短半径弯头（半径= 1.0D）仅用于空间不允许使用长径肘的位置，并且需要降低弯头的成本。在夹套管道中，短半径弯头用于芯管。
Bay long radius elbows (radius > 1.5D) are sometimes used to transport high viscosity fluids for specific applications, such as slurries, oligomers, etc. For pipe bends with a radius greater than 1.5D, these are usually used and can be made to any radius. However, 3D and 5D elbows are the most commonly used elbows with short radius (radius = 1.0d), which are only used in places where long radius elbows are not allowed in space, and the cost of elbows needs to be reduced. In jacketed pipes, short radius elbows are used for core pipes.
这里D是标称管道尺寸，单位为英寸。
Here D is the nominal pipe size in inches.
有三个主要参数决定了肘部的半径选择。空间可用性，成本和压力下降。在压降是主要考虑因素的情况下，管弯头是优选的。
There are three main parameters that determine the selection of elbow radius. Reduced space availability, cost and pressure. When the pressure drop is the main consideration, the pipe elbow is preferred.
应尽可能避免使用短半径弯头，因为方向突然变化会导致高压降。
The use of short radius bends should be avoided as far as possible, as sudden changes in direction can cause a high pressure drop.