What is a Centerline Radius and How is it Measured?

The centerline radius, commonly known as the CLR, is the distance from the exact center of an elbow’s curve to the centerline (axis) of the pipe.

This is more clear if you look at the image below. The CLR is expressed as a number multiplied by the pipe or tube size.

Image expressing the center line radius of the elbow

How to Measure Your Centerline Radius

To calculate your centerline radius, measure from the center of the elbow at the centerpoint of the bend to where the ‘degrees of bend’ lines intersect (see image above). In fact, taking this measurement from anywhere on the elbow will give you the CLR. The distance from the intersecting points to the elbow’s center is your CLR.

The centerline radius is only one measurement on your elbow. You may also need to know the degree, line size, and tangential points in order to measure your elbow. Watch our video on how to measure a pneumatic conveying elbow for everything you need to know:


Why You Need to Know What Your CLR Is

If the elbows in your pneumatic conveying system need to be replaced due to wear or abrasion or if you’re designing a new layout for your system, correctly measuring your existing elbows to ensure you order the right size is key.

The reason you need to know your centerline radius is so that you know the space your new elbow needs to fit into - a 36-inch centerline is a lot smaller than a 48-inch CL, for example. In order to know what’s going to fit, you need to know the size of the space and the size of the elbow you’re replacing.

Other than the line size and making sure that you have the right degree, there are only two variables that affect the size of an elbow: one is the CLR and the other is the length of the tangent, or the straight part of the elbow that comes off the curve. Basically, if you don’t know the CLR, you don’t know how long your elbow is. 

That’s why knowing your centerline radius is so important, because if you get it wrong and don’t get the correct elbow fit for your pneumatic conveying system, it can be an expensive mistake in terms of both money and time. 

If you need help in measuring the centerline radius of an existing elbow, it’s best to talk with an expert in pneumatic conveying elbows so you can ensure you get the correct measurements and a solution that best suits your needs. 

At Progressive Products, we won’t sell you anything you don’t need – we’ll sell you the best elbow that’s right for your individual system. Contact us today to find the right solution for you.


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