by Jon M. Casey

For wood waste recyclers who are looking for the latest in horizontal wood grinders, the Vermeer HG6800TX could be the answer. Introduced at CONEXPO-CON/AGG 2017, this impressive grinder is engineered to produce large volumes of ground material. Boasting either a CAT C27 Tier 2 or a CAT C27 Tier 4 Final power plant, each rated at 950 horsepower, the HG6800TX features an all new design with a number of production improving features.

According to Brad Van Rheenen, Vermeer application specialist, the improvements on the HG6800TX begin at the in-feed table where the sidewalls have been lowered and are flared out to aid in the grinding of whole trees. It also helps reduce the number of times the loader operator needs to handle the material. Additionally, the in-feed table is sloped at an uphill angle to the mill. This slight angle helps improve the flow of material into the mill, while improving the cutting angle at the mill. This design improvement helps to prevent “power feeding” which leads to material wrapping itself around the mill.

A closer look at the new Series III duplex drum design reveals improvements in the ease of replacing worn hammers. The drum is now hard faced for greater wear as well. There are still two screens in this new unit, similar to the two screen design of the HG6000. These however have added surface area for additional throughput. The anvil is easier to install and replace than previous models. An exterior control allows the operator to adjust the distance between the anvil and the cutter tips.

“The feed roller has been greatly upgraded,” said Van Rheenen. “Made of AR-400 steel, and featuring 4-inch cleats, this heavier duty design is more durable than in the past. We have hydraulic planetary motors on each side of the roller. This gives us double the pulling force of previous models. The geometry of the hydraulic cylinders on the exterior of the feed roller gives this unit increased crushing power. In our testing phases, we fine-tuned the crushing power for optimum results.”

“The mill lid opening is 38 inches. The feed roller itself goes up to 50-inches. The mill strike-off point is set back so that material can move closer in to the mill which helps allow for larger material to pass into the mill if it is rolled around and is repositioned,” he said.

DT-6 and more adjustable discharge

Moving to the rear of the unit, Van Rheenen noted that the discharge conveyor can now be positioned horizontally, giving operators greater serviceability of the conveyor.

“The radiator sits 90 degrees to the machine rather than on the side of the engine. This helps conserve space, making the grinder more compact. The addition of a shield atop the discharge conveyor helps prevent excess dust from collecting in the radiator fins.”

The HG6800TX also features the optional DT-6 dolly transport system, a removable unit that can be integrated onto the grinder, giving it roadworthy transportability between job sites. While the TX model grinder is so noted because if its independent tracked capabilities, by attaching the DT-6 to the discharge end of the grinder, a conventional truck/tractor can hook up to the front end. Once the onboard air bags are inflated to lift the machine to give it additional ground clearance beneath the tracks, and the air brake lines are connected, the unit can be roadworthy in a matter of a few minutes. When not in use, the DT-6 dolly can be towed by a smaller vehicle to move it out of the way.

Alongside the machine, Van Rheenen pointed out the grinder’s new belt adjustment capabilities. With the HG6800TX, the operator is able to adjust the belt tension on the V-style belts by pumping up a hydraulic idler that maintains the proper tension on the belts. With this belt tensioning system, there are transducers that “look at” hydraulic PSI and send that number to the control panel and the operator’s remote. The operator can then monitor this number. These sensors are not necessarily waiting for the belt to slip to give any kind of a warning. “Loose belts cause a lot of problems,” he said. “This feature is a ‘really big deal!’”

Damage Defense

Van Rheenen said that one of the unique features of the HG6800TX is the new Damage Defense monitoring system. “This system can help detect when there’s been a metal contaminant entering the system,” he said. “The Damage Defense system has a sensor on the mill bearing and one on the anvil. When the cutter tips ‘tick’ the contaminant, the system feels it and automatically idles the engine down and reverses the infeed chain to allow for removing the object.”

Accordingly, if the operator desires, the Damage Defense system can be regulated to allow a certain amount of metal to pass through it so it doesn’t cause nuisance tripping of the grinder. For example, if a recycler is grinding wood with staples or nails in it and a bolt or other heavier metal item comes into the mill, Damage Defense can be fine tuned to help reject the larger items while allowing the smaller ones to pass through.

“With this system the operator has a quick and easy way to get the machine running again, after a contaminant has been detected,” he said. “You would need to set the sensitivity for each application. This doesn’t eliminate damage, but it is designed to help.”

Finally, there is a new style remote control that controls everything except turning the key in the ignition! “The remote control is a new, more user friendly design than with previous models,” he said. “The control panel on the machine is now equipped with weather proof switches for better performance and reliability.”

“We are planning regional demonstrations during 2017 to give dealers and customers a closer look at this new product.” For more information about Vermeer, visit www.vermeer.com .