How to prevent wear on your PE pipeline's bends

by Advanced Piping Systems
on March 10, 2020
in

HDPE, Poly Pipe

When it comes to wear prevention, the approach that you take will vary from someone else's. It comes down to the use case for your particular pipeline. If your pipeline is transporting slurry, or tailings, for example, you will have a very different approach from someone whose pipeline is simply carrying water.

However, polyethylene pipe is more durable than steel, even in situations where your pipeline is transporting fine silica sand, sharp or lumpy media, or highly corrosive, treated water.

Besides scheduling a planned shutdown at regular intervals to maintain your pipeline, it pays to think about wear prevention when it comes to new sections of pipe or new fittings.

Where does it make the most sense to think about wear prevention on your pipeline?

The low-hanging fruit is on the bends of your pipeline.

What to look for in high-wear pipe components

There are a number of ways to approach the bends in your pipe. In a maintenance situation, look for a consistent wall thickness in your pipe materials and components.

Even though it's generally not possible, imagine grabbing and bending a piece of pipe. Doing this stretches the back of it, because something has to give in order to create the bend. When bends are created in pipe, what actually happens is that the rear wall thickness reduces.

The 1.5D Sweep Bends that we sell solve this problem because the pipe wall has a consistent thickness around the back of the bend. What it does is give you a greater wear surface at the back of the bend, which means it's not going to wear out so quickly.

In high-wear situations, you have some different options: Even the 1.5D isn’t going to help you!

The options you have are:

  1. A hardback bend
  2. A blocked-off T-junction.

Both of these allow the media in your pipeline to create a wear pad from itself. The major benefit of both methods is that the media runs past itself, instead of the inside of your pipe.

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Benefits of a hardback bend

A hardback bend has been through a process in which there is an extra wall thickness at the back of the bend. This enables the fail-point of the bend to work to your advantage.

In a low-pressure slurry line, for instance, hardbacking a bend allows the slurry to create a pocket of its own media once the inside of the pipe wears through. The slurry, pumped through the pipeline, wears a pocket in the back of the bend, then fills that space itself.

Eventually, the slurry is running against a wear pad of its own construction: The slurry runs past itself instead of your pipe.

Benefits of a blocked-off T-junction

Putting a T-junction on the pipe, and then blocking off one end of the T, is a short-cut to a similar situation.

The blocked-off T will quickly fill with the media carried by your pipeline. It creates a big plug of itself, so instead of your media continuing through the main line of the T, it will simply start turning on its own wear pad.

Please note:  If you’re going to use this method, be aware that your pipeline’s media has to be heavy for this to work. If it isn’t, the T will just create a turbulence, which will wear out your polyethylene line really quickly! If you do have heavy media, it’s a simple and effective way of preventing wear.   Also, a blind plate needs to be fitted as this can block especially when the media is inconsistent.

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