Plant & Equipment

Vibrating screen boosts production at sand and gravel plant

Before installing the Premier ES303 screen from Metso, Woodlands Sand & Gravel Plant had experienced declining reliability and costly, time-consuming downtime to replace screening media on its old vibrating equipment.

The ES303 screen, in operation since early 2015, is functioning smoothly and helping to boost production and efficiency at the plant.

The Woodlands plant is located in Conroe, Texas, about 64km north of Houston. It is owned and operated by Lehigh Hanson, which operates more than 200 aggregates plants in the USA, and whose parent company is HeidelbergCement, one of the largest aggregates producers worldwide.

New screening solution

The Woodlands plant is on the west fork of the San Jacinto River, where, according to plant manager Jay Jackson, an electric dredge is used to mine natural sand and gravel.

Material is pumped from the dredge to the plant through a pipeline, where it enters a velocity box, or tank, which separates the gravel from the sand. The sand is then pumped in below the screen, while the clay and gravel are processed through the screen.

“The gravel goes across the Metso screen,” Jackson said,” and that’s what we’re using the Metso screen for – the natural washed gravel.”

The Premier ES303 uses urethane screening media on all three decks. The top deck screens the clay, the middle deck is used for mid-size gravel and the bottom deck is for the extra fine gravel that drops through the bottom of the screen. The ES303 also features three water spray bars, to spray the gravel and remove the clay.

The choice of vibrating screen came as Lehigh Hanson identified a need to modernise its production capabilities at the Woodlands plant, requiring an efficient screen that could produce gravel to its specifications and reduce maintenance and downtime.

The new vibrating screen would replace a 6m x 2m incline screen, which had reached the end of its useful life. In addition, replacing screening media on the old screen was labour intensive and time consuming.

After a thorough review of vibrating screen brands on the market, Lehigh Hanson contacted Crisp Industries, Metso’s crushing and screening distributor in Texas. Crisp Industries recommended the Premier ES303 screen.

This design for horizontal screens does not rely on shafts timed with gears to create an elliptical motion, and therefore has fewer parts to contend with.

In addition, when a bearing change is required, the quick changeout for Metso’s modular vibrator mechanism requires less downtime than a traditional horizontal screen.

Lehigh Hanson felt these were important benefits for its operation.

Greg Venghaus, territory salesman at Crisp, assessed the situation at the Woodlands plant and suggested replacing the old incline screen with the ES303.

“They liked the new technology,” Venghaus said, “and were willing to be the first to adopt it.”

Enhanced screening efficiency

The Metso Premier ES303 is a high energy horizontal screen designed to deliver up to 25 per cent more screening capacity compared with conventional screens of the same size.

The two unbalanced shaft lines in the screen rotate in opposite directions, generating a high energy elliptical motion.

This aggressive screening action enables the Premier ES to separate materials with consistency and accuracy, even in damp and sticky conditions. Jackson said the screen fit into the same footprint as the old screen, requiring only minor modifications.

“We just pulled the old one out and put this one in,” he said. “Crisp Industries provided project management and installation services for the ES303 screen under the direction of Doug Swoveland, operations manager at the company’s branch in Seguin, Texas.

“Although improving reliability and reducing downtime were the primary goals with the new screen, increasing production and efficiency were strong factors as well. I think it’s done very well, and it has increased both production and efficiency,” Jackson concluded.

Chad Miraglia, Woodlands Plant’s operations manager, said: “With rock and clay we are probably doing an average of 100 tonnes per hour (tph). I’ve seen it do 160 to 170 tph of rock production at its highest.”

Metso Premier ES screens are also designed for optimal durability and maintenance. Screen media changes are quick and easy.

“It’s absolutely wonderful the way we change out screening media,” Miraglia said. “The old screen had the big metal screens that were very difficult to install, very time consuming. Now if we want to make a screen change, it’s very fast, very efficient. It does a very good job.”

The ES303 screen has proven a big hit with the team at the Woodlands plant.

“I can tell from my employees’ standpoint that they absolutely love it,” Miraglia said. “They rave about it. In every respect – whether that’s time saving or cost-effectiveness – it’s exceeded our expectations so far.” 

Source: Metso

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