From countries adopting policies to help reduce greenhouse gases to people looking for more natural, sustainable solutions for heating their homes and feeding their plants, quality processed wood material is in high demand. Capitalizing on the growing number of revenue streams for wood chips requires more than just a connection with customers — forestry and logging companies also have to be able to produce a variety of material sizes to meet the needs of the end user.
A common issue forestry companies face is not having the ability to produce the appropriate size of material to meet the needs of their wide variety of customers. For example, the biomass industry usually prefers smaller or micro-sized wood chips to accommodate pellet stoves, wood burning plants and so on, but the chippers that crews use in the field are not able to produce the appropriate size, resulting in the need to regrind material. Regrinding material multiple times can significantly impact a business and requires additional equipment.
Manufacturers like Vermeer have recognized the market demand for wood chips of varying sizes and have developed equipment that delivers more sizing options.
According to Vermeer applications specialist for Recycling and Forestry Brad Van Rheenen, the design of Vermeer whole tree chippers gives contractors the ability to produce a broader range of chip sizes. “We offer two different drum options on Vermeer whole tree chippers — a microchip drum to produce a range of smaller sized chips, and a macrochip drum that can also be easily adjusted to produce different, larger sizes of chips,” he explained.
Two drum options
The main difference between the Vermeer microchip and macrochip drum options is the number of pockets. “The microchip drum has two full width pockets, while the macrochip drum only has two,” Van Rheenen said. “Producing smaller chips requires more cuts per revolution, so by doubling the pockets and knives on the microchip drum, we are able to produce smaller chips in one pass.”
Operators can add spacers under the knives for each drum size to make additional sizing adjustments. “Whether a company selects the microchip drum or a macrochip drum, the ability to make quick adjustments between jobs or in the field is important,” Van Rheenen added. “Making a few small adjustments can help reduce the amount of regrinding that has to be done to fill an order with different material size requirements.”
Selecting the right drum
The Vermeer microchip drum produces chip sizes between 1/8” (3.2 mm) to 5/8” (15.9 mm), which is suited for producing wood pellets for residential and wood fuel plants, as well as chips for landscaping, gardening, animal bedding, composting and playground applications. The macrochip drum can produce chip sizes between 5/8” (15.9 mm) and 11/4” (31.8 mm). Applications for wood chips in that size range include silt socks, erosion control, capping landfills, mulch, wood fuel plants and land clearing.
To determine which chipper drum is right for a company, Van Rheenen recommends contractors evaluate how the processed material is being used and which markets are they being sold to. “If the chips are simply going back to the forest floor as part of a land clearing project, it may be more efficient to use a macrochip drum and a large depth of cut,” he said. “Larger chips will not decompose as rapidly as smaller ones. However, if a company is selling the chips to an end user, the drum type will depend on the needs of customers. The goal should be to create a size that most closely matches the needs of the customer.”
Making adjustments
While having different drum types provides companies with a lot of flexibility, the ability to easily make size adjustments to the drum is equally important. On many chippers, making adjustments or performing routine maintenance can be time-consuming and labor-intensive because the process of babbitting requires working with molten lead. Vermeer developed an innovative approach with its patented pusher bolt knife design.
“Knives on Vermeer whole tree chippers can be positioned quickly with just a wrench,” Van Rheenen said. “We use threaded holes in the end of the knives where pusher bolts take the place of babbit. This design makes it much easier to make adjustments and sharpen knives. Our unique pusher bolt system helps prevent knives from sliding outward toward the shear bar.
“Another unique feature of the Vermeer microchip and macrochip drums is that they are completely threadless,” Van Rheenen added. “Instead, we use a replicable hex nut for knife retention, which makes it much easier to replace a knife if it gets damaged.”
The design of Vermeer chipper drums makes it easier to efficiently make adjustments, which is beneficial for forestry and logging operations that cater to a wide range of customers. It also helps reduce the need for regrinding.
Growing demand
As more and more countries, communities and individuals discover the advantages associated with using natural and renewable wood chips, markets will continue to grow, and new ones will emerge. To create chip sizes for a broad range of applications and help minimize operation costs, choose wood processing equipment that can be quickly and easily adjusted.
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