No One Answer

Wood recyclers approach their jobs from many different angles and with widely differing materials to process. Fortunately, equipment makers offer an increasing variety of machines to turn this assorted feedstock into marketable products.

With a stream of feedstock ranging from railroad ties and hefty timbers to thin dimensional lumber and pliable green waste, it is unlikely that any one machine can dominate the wood recycling market.

Manufacturers are finding, though, that grinding and separating machines that can perform multiple functions often have a waiting audience in one or more niches of the wood recycling industry.

Setting a Volume Target

Equipment manufacturers have increased the volume range of wood grinding and chipping machines available at both ends of the spectrum. Massive machines are now available to process large volumes around the clock, while smaller portable units are also welcomed by some recyclers.

CMI Corp., Oklahoma City, Okla., has a series of grinders under the BioGrind and MaxiGrind names in a range of sizes. The BioGrind 500 is a horizontal grinder with an accompanying knuckle-boom loader. “The operator runs the loader and has controls to the grinder,” notes CMI product manager Mike Rodriguez. “The set-up allows for open-end feeding and gives the operator an unobstructed view of the infeed conveyor.”

Rodriguez calls the clear view “invaluable” in C&D applications, since it gives an operator the chance to remove ungrindable objects such as structural steel or high-PSI concrete.

Demand seems to have increased for the higher volume wood processing machines, according to Rodriguez and other equipment manufacturers and vendors. “It seems like there is a lot of interest in starting to shift away from portable to fixed-site installations,” says Mark Lyman, president of West Salem Machinery, Salem, Ore.

Lyman notes that several West Salem equipment buyers have opted for fixed site grinders powered by electric drives rather than diesel engines. “There are a lot of operators doing this in large, metropolitan areas—areas where they can command money either on the front end as tipping fees or on the back end with a product that can be sold,” he says. “A lot of recyclers are selling the colored mulch material, which is opening up the market for clean wood.”

But not all the action is at high-volume stationary facilities. Grinding on-site with a mobile machine can still be the most affordable way to process wood construction, demolition and land clearing debris in many instances.

Packer Industries, Mableton, Ga., has introduced its 750 model marketed toward the residential construction market. “It’s small enough that it can be pulled by a pickup truck and can be used by builders on a single lot or within subdivisions,” says Packer Industries president Ken Patterson. Among the materials the portable machine can grind are scrap dimensional lumber, plywood, gypsum, sheetrock and even blocks and bricks, according to Patterson.

He says the small horizontal grinder can be used by builders (or a clean-up service provider) during all three phases of the residential construction process. Ideally, clean wood could be processed during the framing phase, creating a landscaping product that could be used on-site.

During the second phase when drywall or sheetrock is added, the gypsum scrap could be ground to create a calcium soil additive product that also can be used on site.

Finally, any scrap brick or block can be processed by the machine to create a powder that can be spread across the yard. Using the grinder in this way can save a builder from one quarter to one half of the customary disposal costs, or about $500 per house, says Patterson.

John Heekin, president of Fecon Inc., Cincinnati, says 90% of the horizontal wood grinders sold by his company are diesel-powered mobile units.

Peterson Pacific Corp., Eugene, Ore., offers a grinder mounted on tracks that can range about at larger sites. “They like the mobility of the tracked machine, particularly for off-road use,” says Peterson Pacific marketing manager Dave Benton of the HC 2410 model.

“One is being used at a housing development where trees are being cleared, de-limbed and the merchantable timber is set aside for shipment to lumber mills. The track-mounted grinder grinds the rest,” says Benton.

Handling an Assortment

Although grinders are made and marketed to process wood, in many C&D applications, a wider assortment of material is likely to find its way into the machine.

As noted in respect to the residential clean-up task with its gypsum, brick and block, construction and demolition contractors and recyclers are not always dealing with a stream consisting of wood only.

For a number of recyclers, wood is just one material of several that they process and from which they create a marketable material.

Ed Kramer, a sales engineer with American Pulverizer Co., St. Louis, says his company’s model SRS 36-156 auger-style machine has found favor with recycles of railroad ties, who are processing a stubborn material that often contains a healthy portion of attached metal objects.

The company’s auger-style machines “can take large, long pieces of material” and can work as pre-breakers before the material leaving the auger heads for a more conventional shredder.

According to Kramer, the SRS 3-156 auger-style machine can be configured with a belt magnet to pick up steel tie plates and spikes, leaving railroad tie processors “with metal they can sell” and with a clean wood stream that “they can further reduce to two-inch chips that can go into the boiler fuel market.”

The American Pulverizer model “eats whatever we throw into there,” says Kramer, who adds that the machine’s large hopper can be fed with a front end loader or a hydraulic handler with a grapple attachment.

It is an example of a machine that can be used to process not just wood, but also other materials making up the overall C&D debris stream.

Grinding that takes place on the job site will almost certainly involve a mixture of materials. “A lot of portable machinery is used to process the nastier stuff and a wide variety of stuff,” says West Salem Machinery’s Lyman. “Operators can be confronted with piles of material they are not familiar with.”

The Beast Recycler made by Bandit Industries, Remus, Mich., is a machine that has been adapted to recycle not only a variety of wood types, but also other C&D materials such as asphalt roofing shingles.

“The only unique maintenance procedure is the use of an asphalt solvent that is sprayed in the radiator the night before being pressure washed,” says Eric Yonke, president of an Ontario paving company using the Bandit to process shingles.

CMI Corp.’s MaxiGrind machines use “an automatic hydraulic push ramp designed to feed extremely heavy materials such as asphalt or brick and block,” says Rodriguez, who calls the MaxiGrind “one of the most popular C&D machines in its price class” due in part to its ability to handle a variety of materials.

Some wood markets, however, ultimately require a machine that will create a wood chip or mulch product that meets consistent specifications. Often, operators are best off having a machine dedicated to this specific wood grinding activity.

“It really depends on what type of customers you’re selling to,” says Rodriguez. “A contract grinder or C&D grinder may want high-volume reduction, and not necessarily a tight product specification. But decorative mulch end markets put size precision over high-volume production at the top of their list.”

Configuring a sys

Not every wood recycler needs to think in terms of setting up a wood recycling system. For those handling green waste, a reliable chipper or tub grinder may accomplish what needs to be done in one step.

But for many other operators, several steps involving material handling, separating, size reduction and end markets preparation may need to be set up in tandem to create an overall recycling system.

“Vertical machines may be preferred by some operators because they fit better in a system, or as a component of a system,” says West Salem Machinery’s Lyman.

Screening machines designed to separate wood pieces by size either before or after grinding have become an established part of many wood recycling operations. Screens can be configured using discs, rods known as “fingers,” grates with different sized openings, or as cylindrical trommels with grates that turn.

“We have been supplying a lot of C&D operations with our disc screens,” says Lyman. “They are high-volume classifiers that work well at the front end of the mixed C&D process to remove dirt and small fractional-sized materials. It basically cleans the material.”

Processors of pallets or demolition wood, in particular, will need to configure one or more magnets into their systems to remove nails and other fasteners.

Coloring systems have been well received by wood recyclers making products to sell into the landscaping market. Adding green or wood-toned dye to shredded waste wood allows the often faded or graying material to compete with landscape products made from green waste.

Fecon’s John Heekin says the mulch colorizing systems introduced by his company are selling at a 300% better pace than they were three or four years ago.

He says the company’s two systems—a batch colorizer for smaller volumes and a continuous system for larger production—are used by recylcers to produce mulch sold to landscape and garden supply wholesalers, while others bag the product for sale by retailers such as Home Depot.

“Mulch colorizing offers the most lucrative option for recycled wood markets,” says Heekin. “The machines can probably generate close to $2,000 per hour in gross profits,” he remarks.

Safe and Sound

Whether operators are running large grinders and a comprehensive system or just chipping modest amounts of wood, safety and reliability are uniform requirements.

Peterson Pacific’s Benton says his companies line of horizontal grinders—ranging in size up to the 7400 model with a 1,000 horsepower engine—have always been designed with safety in mind.

While tub grinders might throw debris within a defined circumference of the operation, well-designed enclosed horizontal grinders can eliminate many aspects of the problem.

Even smaller models, such as Brush Bandit chippers from Bandit Industries, can be configured to include safety features such as an engine disable switch, a wooden push-paddle and an infeed chute pull-cord stop.

Business owners also demand reliability, with the avoidance or minimization of downtime being a primary goal. “The key for C&D operators is to have a durable machine,” says Benton. “It’s got to be able to withstand the impact of some of the non-crushable material that might enter.”

CMI Corp. grinders feature a patented hydraulically shock-protected grinding chamber, with cylinders that allow the grinding chamber to be flexible when an “ungrindable” enters the chamber. Rodriguez says the chamber will flex or pivot rather than being held in place and creating a dent.

Many CMI models also feature steel infeed conveyors, which Rodriguez says are more durable and “ideal for applications like C&D where metal and brick are part of what comes in.”

Larger fixed-site machines are often adaptations of “mill-duty” machinery, says West Salem’s Lyman, so they are engineered and designed “to go 24 hours a day, seven days a week. Our focus is non-stop grinding—that’s our tag line. In larger facilities, it’s important to minimize downtime.”

Whether part of a larger in-place system or part of a job site “hit and run” mission, the search for reliable processing equipment is likely to always be foremost in the minds of wood processing equipment buyers. C&D

(The author is editor of C&D Recycler magazine.)