If used in the right soil conditions with the correct scraper train and scraper tractor, a pull scraper system promises to move material faster with less initial investment, less support equipment, fewer operators and lower operating costs compared to conventional methods.
Mike McCrory, Eastern regional sales manager, Miskin Scraper Works, says the biggest advantage comes from the system's ability to work without support equipment. "It loads itself with no help from a crawler dozer and unloads itself while dumping on grade, negating the need for a crawler dozer to smooth out the dump area," he points out.
But you really have to know what you're doing to realize the savings. Bennington Equipment, a John Deere dealer, made the decision several years ago to get into the scraper business. "Basically, we jumped in with both feet, and a lot of the things we tried didn't work," says Brad League, scraper product specialist. "They cost us a lot of money. It took a period of years to learn everything."
This experience now cuts the learning curve for Bennington Equipment's customers. "Now that we have that experience, we try to set up customers properly," says League.
When exploring pull scraper systems, look for a supplier that can provide practical jobsite experience. Sometimes small mistakes in the setup result in an unfavorable experience. "Maybe if you used a different tire or a different scraper, you may have been satisfied," League notes.
Pull scrapers have evolved. "They are tending to get a little easier to load and a lot less maintenance," says Allan Clark, president, Clark Bros. Inc., Dos Palos, CA, a construction and land leveling company that constructs building pads, drains and canals, etc. Its equipment fleet includes both motor wheel scrapers and pull scraper systems.
Clark feels today's pull scrapers have become more durable. "We had a lot of trouble with bending them in really hardpan conditions," he notes. "We don't have as much problem today as we did."
Pull scraper systems are also overcoming one of their traditional drawbacks - top speed limitations of the scraper tractors. "In some cases, when the haul is longer than one mile, the contractor may opt to use excavators or conventional scrapers," says James Hausner, vice president of marketing, Reynolds International. "However, many opt for pulling up to three units per tractor. As far as speed and gradeability, motor wheel scrapers can run as fast as 30+ mph, whereas tractors average around 23 mph, with some exceptions."
Those exceptions include industrial tractors that are capable of pulling scrapers at speeds comparable to a motor wheel scraper. "With the introduction of the new high-speed industrial tractors, the haul distance is no longer a factor," says McCrory. "The two most prevalent trends are the use of higher capacity pull scrapers, and the use of industrial tractors specially built for pull scrapers."
Mission Paving Co., Mission, TX, has found pull scraper systems a highly effective way to move soil. The site work contractor owns four self-propelled elevator scrapers, plus three tandem Reynolds 12C scraper rigs and a tandem 17C scraper rig - all pulled by 8000 Series John Deere tractors.
"The elevator scrapers are used in applications where we need to pick up dirt that has either been moved or handled by another machine, or to clean up an area and move the dirt," says David Valadez. "The elevator scrapers are very high maintenance in comparison and the annual expenditures are quite a bit more vs. the pull scrapers."
This is reflected in the usage. "We probably run between 300 to 500 hours a year on each of our elevated scrapers, where we run 1,500 to 2,500 hours with each of our tractors [with scrapers]," says Valadez.
The pull scrapers have proven to be high-production tools. Soil conditions on jobsites vary from heavy clays to sandy soils, and most cuts are done at between 3.5 and 4.5 mph. Given a 300-yd. haul distance, Valadez reports he can move 2,000 yds. a day with the 12-yd. tandem pull scraper rigs, and 3,000 yds. a day with the tandem 17-yd. scraper rigs.