by Jon M. Casey and Pat McBroom, Murrysville Machinery Company

Derry Stone & Lime Company, near Blairsville, PA, has continued to expand and grow by reacting to new and growing markets, like Pennsylvania’s State approved Anti-skid market. Owner Dave Herrholtz said that in the past several years they have continued to make improvements and upgrades to their operation, to meet the increasing demand for quality material and to meet their customer’s needs. One of these markets is the State approved Anti-skid market. “We were already supplying some of that market, but we needed to increase our volume and tonnage,” he said.

As a part of that process, Dave and his team went to CONEXPO-CON/AGG 2014 in Las Vegas to research many screen options available. Ultimately, he went with the KPI/JCI/AMS PTSC2618VM High Frequency screen. He found that the quality of construction, the way it was engineered and the machine’s production capabilities and functionality made it the unit he needed. More importantly, the reliable dealer support he has had through Murrysville Machinery Company, made the PTSC2618VM the perfect fit.

According to Don Cunningham, quarry superintendent, the PTSC2618 has been one of the best investments they have made at the Quarry. “This screen has more than doubled our tonnage of antiskid chips and given us a quality finished spec product. The screen is extremely easy to service and maintain. We can change screens, and make adjustments to the hydraulic flow to compensate for changes in moisture or environmental conditions much easier than with other screens.”

While we toured the plant with Don, we could see how the addition of this new technology added considerable tonnage to their daily production. With the primary geology being a Benwood limestone and sandstone formation, and the company’s most desirable products being anti-skid and limestone dust for agricultural application and coal mining water treatment applications, the ability to increase daily production of these two important products was the motivation for finding a workable solution.

As shot rock is dumped into the primary crusher, a Pioneer 3055 jaw crusher, it is crushed and then goes over a scalping screen making two cuts of the material. The R4 goes to the surge pile to feed the secondary, a Nordberg HP300 cone crusher while the 3s and 2A material go to their respective stockpiles. Material is conveyed from beneath the surge pile to the secondary and then once crushed; it is screened over a Nordberg triple deck screen that sizes the material as 1B, 2B, anti-skid and Dust. From there, the remaining smalls go to the new AMS unit for final screening. Don strongly recommends the purchase of the optional vinyl cover for the screen, which has allowed them to run year round, in rain, sleet, snow, wind and hail.

The PTSC 2618VM is a PEP Duo-Vibe High Frequency screen manufactured in Sterling IL. It is offered as chassis mounted for transport and ease of setup, as track mounted unit for mobility at the site, or inline on a stand or structure.

Astec Mobile Screens’ High Frequency screens are engineered to provide higher production capabilities and more efficient sizing compared to conventional screens. High frequency screens feature aggressive vibration applied directly to the screen cloth that allows for the greatest amount of fines removal in the market. The screen features include a double deck or triple deck unit. The double deck model features a 6’ x 18’ top deck and a 6’ x 12’ bottom deck. Triple deck units have two 6’ x 18’ decks and a 6’ x 12’ bottom deck. Eleven hydraulic vibrators drive the screen action, running at ranges from 3600 RPM to 4200 RPM.

What is most noticeable is that the screen angle is hydraulically adjustable to ranges from 36 degree to 42 degrees. This steep incline, plus the selection of the appropriate screen media for the work at hand, gives this technology the distinct advantage for dry fines screening. Don said that when the material passes over the screen, it’s as though the dust is being sucked right through the screen. The anti-skid keeps moving to the discharge and onto the conveyor. With the screen set up correctly “tweaked” as Don said, there’s no screen blinding and the unit operates flawlessly.

Typical applications for these advanced, high-tech screeners are: asphalt chips: ¾” to ¼”; manufactured sand: ¼” to 20 mesh; concrete stone: 3/8” to 20 mesh; Ag Lime and Gypsum: 12 to 30 mesh; and recycled asphalt (RAP): ¾” to 3/16” to 20 mesh.

Murrysville Machinery Company

Murrysville Machinery Company specializes in crushing, screening, conveying, and recycling equipment and technology and is located in Westmoreland County, Pa. Murrysville Machinery Co. has sold, serviced and supported, several of these high frequency screens since their introduction. Pat McBroom, the Murrysville Machinery Company representative for Derry’s area was one of the added reasons that Derry Stone and Lime went with this new unit.

“Having a local dealer like Murrysville Machinery which is very service minded and knowledgeable of the products they sell, was also a key factor in the decision,” said Cunningham. “Murrysville and KPI/JCI/AMS were very helpful with the training, setup, service and dial in of the screener.” For additional information, please contact Murrysville Machinery at 724-863-7000 or email: sam@murrysvillemachinery.com or pat@murrysvillemachinery.com