How to get the best performance on bends

1 November 2020

Training

When considering performance fittings for piping systems, the suitability and type of bend used on a project is essential to its functionality.

In this article we consider bends that are of high-performance for slurries and media applications, and the quality required for a high-performance sweeping bend.

Best practice bends 

When it comes to the best types of bends for piping projects, we would recommend using either short radius bends, multibends, or sweep bends, as they each have a gentle curved radius which keeps the flow moving with minimal disturbance. 

As the space and dimensional limitations of bends are often too tight for larger sweeping bends, APS provides many options of smaller radius performance poly pipe bends that will fit into more restricted spaces. 

For extra high-wear and mining slurry applications APS can reinforce the back of any sweep bend using a hard backed section of HDPE. This doubles the durability of the most impacted area of the bend, while still ensuring you get all of the added advantages of using a poly pipe product.

Getting optimal performance from bends

When it comes to slurries, an important design feature is to minimise turbulence, so that the particles stay suspended in the liquid. To achieve this, the best performing bend will be a long radius bend.

It’s important to select the most appropriate bend radius for your application, either 1D, 1.5D or 3D, depending on the pressure, velocity and coarseness of the medium you are working with. 

If sweep bends are the best solution for you, make sure they have been manufactured to the highest-quality, with a constant, unrestricted bore size that matches the type of pipe you are using. 

Quality sweep bends are not easy to manufacture. As a result, it’s important to keep in mind that many 3D sweep bends on the market have been made in a very basic way.

You should be able to measure the quality of a sweep bend by checking that:

  • the ID of a performance sweep is constant;
  • it has no ovality and wall thinning; and
  • has no moulding divots.

At APS, our sweeps are manufactured to a stringent high-quality standard. This allows the sweep bend to be cut in half (or anywhere on the radius) while also ensuring that the pipe remains within tolerance.

A true performance fitting, such as those we supply at APS, will give you an incredible advantage if you are unsure of the angle you require, it will also save you maintenance and pumping costs down the track.

What fittings should you use on bends?

Short bends will require knife or short fitting clamps, although it takes a high-level of experience to master these specific types of fittings.

Experienced fabricators prefer using short radius bends as they make very tidy fabrications, and the welding beads are also easier to remove, further maximising performance.

Short radius bends are also available in a range of sizes up to 500mm, which Advanced Piping Systems can cut to the angle required, covering most process piping systems.

Due to their elongated spigot lengths, multibends and sweep bends can be welded by either butt fusion or electrofusion methods.

Materials to avoid on bends

Sharps elbows are better suited to pressure water, and gas utilities and services, and should only be used for these applications.

Elbows shouldn’t be used for slurry or gravity non-pressure applications, as the media can settle and block. Elbows also tend to create unnecessary turbulence.