Valves for abrasive materials

What’s the Best Slide Gate or Diverter Valve for Handling Coal, Frac Sand, and Fly Ash?

Many of our customers come from industries where conveying abrasive material is a recurring challenge.  Configuring the right slide gates and diverter valves for those customers is a challenge in its own right. In this article, we’ll take a look at some of the key factors that influence the decision of which slide gate or diverter valve works best for handling these abrasive materials.

Different Level of Material Hardness Cause Different Levels of Wear

Abrasion occurs where the metal components of a valve are worn down through friction as the material handled impacts those components. Prior to considering what type of gate or diverter is required, special consideration has to be given to the characteristics of the material and how it is being conveyed.

Minerals are categorized into a Mohs hardness scale. The scale characterizes the scratch resistance of various minerals by how a harder material can scratch a softer material. Softer materials like talc have a hardness rating of 1, while harder materials like diamonds have a hardness rating of 10. When selecting metal valve components, it’s best to select the proper construction materials that match the hardness of the material handled.

Material Shape Has an Impact on the Effects of Abrasion

The shape of the material being handled is another important consideration. Sand can have a Mohs hardness rating of 7. Sand exists in a variety of shapes. Some sand particles can be round while others can be angular. An angular particle will abrade valve components much faster than a rounded one.

How the material is handled is yet another consideration. For example, is the material being gravity fed through the valve or is the material being conveyed pneumatically through a conveying system at 3,000 feet per minute? Talc, one of the softest minerals, can eventually chisel its way through a substantial metal plate if given a small exit hole and considerable force behind it.

Hard Metal Wear Liners can Alleviate Component Breakdown

Utilizing hard metals or metal alloys for the wear areas is always a consideration. Valves may be manufactured incorporating abrasion resistant plates, chromium carbide overlays, or metals like Hastelloy® to reduce wear from abrasion. Diverters may be manufactured with replaceable wear liners that are constructed of the above-mentioned materials.

Replaceable Abrasion Resistant LinersOver time, worn liners may be replaced with new ones to extend the life cycle costs to the valves. In some instances, an added feature as simple as an interior rock box might be added to address abrasion and prolong valve life. A rock box is an area within the valve that is designed to trap a small amount of the material handled. Subsequent material traveling through the valve impacts on the trapped material as opposed to abrading a liner or plate. When cross contamination of the material is not an issue, this feature is extremely effective.

Manufacturing Experience with Abrasives is Critical

Companies that deal with abrasive products are cognizant of the fact that new equipment begins to wear out starting day one. Equipment installed in these environments needs to be continually maintained. Sourcing valves from an established supplier with the ability to provide support after the installation can help lift the burden of dealing with challenging applications. Their expertise can address the many factors experienced in a particular application and assure the purchase of the best slide gate or diverter valve for handling abrasive materials.