Excavators frequently are used by demolition contractors and C&D recyclers to move material around a job site or recycling yard. Material handlers can offer greater efficiency through better lifting capabilities, longer reach and increased power, but investing in one may not always be the right move.
Construction & Demolition Recycling magazine spoke with Steve Stonehocker, product and application specialist for the Material Handlers division of Caterpillar Inc., Peoria, Ill., to help identify when it is time to time to put the brakes on the excavator and bring in a purpose-built machine.
Construction & Demolition Recycling (C&DR): When moving materials around a job site or at a C&D recycling facility, when does it make sense to bring in a purpose-built material handler?
Steve Stonehocker (SS): Typically material handlers move material within the reach of the machine. Even wheeled material handlers will most often work with the outriggers deployed rather than in a load and carry type of application. There are a few exceptions to that, but if you are planning to move material beyond the reach of the machine, wheel loaders or other pieces of equipment may be a better choice depending on the application.
The concept of a material handler denotes that the machine was designed for a specialized application. Using a standard excavator in any type of material handling application inherently means the machine will be used for something other than what it was specifically designed for, i.e., moving dirt. Using an excavator in a material handling application is a compromise at best and will generally not be the best solution over the long haul.
So, to answer the question, if the application requires moving material within the reach of the material handler, the material handler will be a better choice than a dirt digging excavator. Keep in mind that the machine still needs to be configured for the application, i.e., the right size, the right boom and stick lengths and the right tool.
C&DR: What advantages are there to using a purpose-built material handler at a job site versus using a retrofitted excavator or other type of machine not specifically designed for lifting and carrying?
SS: Advantages are as follows:
- Longer reach. A retrofitted excavator may be fitted with a longer material handling front similar to the purpose-built material handler but will generally not have as much reach as the purpose-built machine.
- Greater lift. A purpose-built material handler typically has as much as 40 percent more counterweight than a standard excavator. This provides the stability to be able to lift greater loads. A retrofitted excavator may have added counterweight to provide similar stability and lift capability but the frame of the machine was not designed for this additional weight nor for the increased lifting loads. So this will result in decreased structural life of the base machine.
- Increased productivity. The engine power, hydraulic design, and machine configuration were designed to work together on the purpose-built material handler. This provides reduced cycle times, maximum payload, and overall improved efficiency which will result in greater productivity.
- Operator comfort and visibility. Purpose-built material handlers are designed with cab risers that provide stability as well as improved visibility. This allows an operator to work the entire day in a comfortable position without being jolted and bounced around.
- Improved engine and hydraulic cooling. Purpose-built material handlers typically have a cooling system that is designed to work in applications with substantial amounts of airborne debris. Debris screens, additional seals, and an automatic reversing fan help to protect the cooling system and keep the engine and hydraulic system operating within reasonable temperature ranges. These systems are also designed to better facilitate cleaning when they do plug. Overall this reduces maintenance and repair costs and keeps the machine running longer.
- Greater resale value. A purpose-built machine will always carry a higher resale value than a machine that has been retrofitted to fit an application.
C&DR: What are some signs that an excavator is no longer the right machine to perform the material handling necessary at a job site or recycling facility?
SS: When the material handling application becomes more than just an incidental operation, it is generally time to consider making the change to a purpose-built machine. Delaying the decision to purchase a purpose-built machine will nearly always result in increased operating costs, especially in repairs to the current machine. Typical issues include cracked structures (boom, stick, and frame), clogged cooling systems, and component failures from either overheated or overstressed engine and hydraulic system.
C&DR: Which tasks does a material handler excel at?
SS: Material handlers, as their name implies, excel at moving material. Most of the time we think of material handlers working in scrap yards moving steel scrap or possibly loading and unloading barges. Caterpillar also builds Waste Handlers which are derivatives of material handlers. These are material handlers that are purpose-built for handling waste, either MSW (municipal solid waste) or C&D. Designed with additional guarding, a heavy counterweight, reinforced frame, enhanced cooling system, additional filtration both for the engine and operator, and heavy duty booms and sticks, these machines work extremely well in transfer station applications.
C&DR: Are there any benefits to retrofitting an excavator to lift and carry material as opposed to bringing in a material handler to do the job?
SS: Depending on the extent of the retrofit, initial cost may be lower. If it’s a small job of short duration, this may make sense. However, some dealers are placing material handlers in their rental fleets so a rental may be more cost effective for that short-term need.
C&DR: How can an excavator work in tandem with a material handler?
SS: In many material handling applications, material must be processed (reduced) prior to loading it out. An excavator can often be used as a tool-carrier for processing material. One example would be an excavator equipped with a boom-mounted shear used to process steel beams prior to loading out for shipment. Other examples might be excavators equipped with hammers or crusher buckets to process stone and aggregates. Another application might be using a material handler with a clamshell bucket to dredge a pond and using an excavator to load out the dredged sand and gravel into trucks to haul away.
C&DR: In what situations might a material handler be less efficient than an excavator?
SS: When digging dirt. Essentially, anytime a machine is mis-applied, it will be less efficient. If a material handler with a long front is placed inside a building with a low ceiling height, it will be inefficient. Bottom line is that the machine has to be matched to the application it will be used for.
C&DR: What recommendations do you have for contractors or C&D recyclers interested in upgrading their equipment to include a purpose-built material handler?
SS: Consult the experts, ask a lot of questions and find out what your options are. Purchasing a material handler is a significant investment. There are a lot of things to consider. First, identify the task or application at hand using the 80/20 rule. Then, determine what tool is needed for your application, i.e. clamshell bucket, orange-peel grapple, magnet, etc. Then look at your site and determine the machine requirements. How much reach do I need? Is there a height limit (ceiling) to consider? What are my surface conditions? Do I need tracks or wheels? How much lift capacity do I need for the tool and payload I selected? Do I have a minimum production target I have to meet? Is there airborne debris to consider? Is this a long-term investment or should I rent or lease a machine for the near term? After selecting the tool and the machine, investigate the dealer. Will parts and support be available to support you with this new machine? These are specialized machines designed and built for your application and you want to make sure the dealer can take care of it.
C&DR: How might lifting capacity vary between a purpose-built material handler and a modified excavator?
SS: A purpose-built material handler will typically have 40 percent more counterweight than a standard excavator. This provides the stability for the material handler to lift substantially more than the excavator. Many times modified excavators will also have additional counterweight. Most of the time, this will be less than a purpose-built material handler and the result is that it will lift less. If more counterweight is added to increase the lift capability of the excavator, it is possible it will be able to lift as much as a purpose-built material handler. But in this case, the frame will not have been designed to handle this additional weight. Even if the frame is reinforced, it will not be sufficient and the result will be a potentially unstable machine with a weak frame.
C&DR: How might hydraulics vary between an excavator and material handler?
SS: Historically, excavators have been designed to dig dirt [and thus] equipped with boom, stick and bucket controls. In the last few years, this trend has changed to use excavators more and more as tool carriers. It is common to find excavators equipped with auxiliary hydraulic circuits including one- or two-way, one- or two-pump flow. Material handlers generally have two circuits, grapple or bucket open/close and grapple/bucket rotate (medium pressure). The medium pressure circuit is often used for a hydraulic cab riser as well.
Steve Stonehocker is product and application specialist for Material Handlers for Caterpillar Inc., Peoria, Ill.