Are classifying tanks playing a bigger role in today’s plants?
Bennington: Yes. For example, when I started my career, most of the material extracted in the Upper Midwest was glacial till. If you ran that across a screen and washed the dirt off, you had C33 sand.
But that material is mostly gone. Now, producers are digging into older alluvial deposits with much more variability and clay content, which means more processing.
Just for fun, would you give the third dealer who calls you with the definition of “alluvial material” a $100 Cabela’s gift card?
Bennington: Absolutely! I'm standing by...
Let’s talk hydrocyclones and classifying tanks specifically. Where does each solution broadly apply?
Natural sand deposits usually follow a bell-curve gradation, from coarse +4 mesh down to fine -100 mesh and pan material. Your equipment choice comes down to where the excess material shows up in that curve.
- If there’s too much +4 or +8 mesh, you’re in screening territory.
- If there’s too much -100 mesh, you need screws or cyclones.
- If the excess sits in the 30s, 50s, or 100 mesh, that’s the classifying tank zone.
Some manufacturers claim a cyclone can replace a tank in every situation, but it can’t.
A cyclone makes a single cut, coarse one way and fines the other. If the feed varies, the products will vary right along with it, because you can’t tune a cyclone to tighten specs as the material changes. In consistent deposits, a cyclone-only setup can work. In variable natural sand, classifying tanks give you the control cyclones simply can’t.
How Does a Classifying Tank Work?
What should dealers know about cost and maintenance?
Classifying tanks are simple machines with little upkeep. The valves and elbows are made of urethane and can last up to 10 years. Electronics eventually need attention, but those can be swapped out in minutes.
Screws and cyclone-based plants carry a similar cost per ton, but the timing of those costs is different.
Screws have small, steady annual expenses like oil, wear shoes, and bearings.
Meanwhile, Spirit® Sand Plants with cyclones and dewatering screens have lighter routine wear. The cyclone apex is inexpensive and dewatering screens run for years. The pump is the major long-term cost, and it typically comes due every four to five years.
What about upfront cost? How is that steering end users these days?
Classifying tanks are expensive, but it's not a fair comparison to screws or cyclone plants. You either need a tank, or you don’t.
There is no substitute.
