Many people do not understand the measurement method from the center of the pipe elbow to the end of the pipe. JIZHONG will explain it in detail. The following will tell you the common calculation methods in the pipeline system, especially in the manufacture and installation of elbows to ensure that the correct size is ordered.
The first step is to determine the elbow type:
Both 45° and 90° elbows are standard elbows, and the distance from the center of the elbow to the end of the pipe can generally be found in the product size table. However, for other customized angles, we need to cut on the standard 45° and 90° elbows during production.
The calculation formula for the distance from the center to the end of the 90° elbow is: Elbow length in mm = Tan(Elbow Angle/2)Elbow Radius in mm
For 90° long radius elbows, the center-to-end size given in the ASME B16.9 size table is the same as the elbow radius. This is because Tan(90/2) or Tan 45 is 1. Typically, custom elbow angles from 45 to 90 degrees are cut from a 90 degree standard elbow. But for custom elbow angles less than 45 degrees, the elbow is usually cut from an existing standard 45 degree elbow. The center to end dimension given in the 45 degree elbow size table must be divided by Tan(22.5) to get the elbow radius for a standard 45 degree elbow. We can then use the above formula to get the custom degree elbow angle.
Calculate elbow center to end dimension for 2 inch nominal pipe diameter elbow at 30 degree angle, cut from 45 degree LR elbow.
From ASME B16.9, the center to elbow dimension for 2 inch 45 degree elbow is 35 mm.
Radius of elbow = 35/Tan(22.5)
Radius of elbow = 35/0.4142 = 84.5 mm
Length = 0.26795 X 84.5= 22.64 i.e. 23 mm Approx.
This method applies to typical commercial pipe fittings like those you're involved in with PVC, CPVC, and malleable iron fittings.
If you need help measuring the centerline radius of an existing elbow, it's best to talk to an elbow manufacturing specialist to ensure you get the right measurements and the best solution for your needs.
At JIZHONG, we won't sell you anything you don't need - we'll sell you the elbow that's best for your individual system. Contact us today to find the right solution for you.
