A Keen Eye and a Steady Hand

Why Use Tippers and Live Floors in the First Place? 

Upon arrival at the landfill, waste has to be deposited on the current working face. Lacking any specialized off-loading equipment, the simplest method is just to let waste trucks self-unload at a designated part of the working face. Upon arrival at the entrance to the working face, the truck continues to drive off of the current temporary access road to a location designated by a spotter. As the spotter guides the truck, he ensures that the truck's movements are synced with the other trucks entering and leaving the work face as well as the heavy equipment spreading and compacting the waste in place. This ensures both maximum operational efficiency and operational safety. The mechanisms used for self-unloading are well-established hydraulic technology. 

So, while this traditional method of waste disposal and placement is sufficient, it can be far from optimum. And a landfill, like any other business, is in business to make money. Operational efficiency is the key to achieving high profitability as much of the capital costs of construction are already baked into the landfill’s permitted design. Only by being move efficient (handling more waste per hour and compacting it as densely as possible) can a landfill operator significantly increase his profitability. 

One potential substitute for truck bed hydraulic jacks is the live floor that allows for horizontal offloading. Horizontal unloading with live floor transfer trailers is needed due to the speed and safety of unloading bulk material like municipal waste. 

What are the advantages offered by a live floor versus standard raised truck bed dumping? Keeping all of the off-loading movement within the body of the truck, instead of moving a large part of the truck body itself, improves both operational flexibility and onsite safety. Live floors are also a relatively inexpensive hack. It is not necessary to buy a brand-new truck to achieve this capability as most existing trucks can be retro-fitted with a walking floor system. The savings in productivity are easy to measure and compare to the capital costs associated with this retrofit. This allows an operator to make an easy apple-to-apples comparison of these costs to see if a live load system is an economically sound choice. In addition to cost savings and efficient productivity, the live load system offers a simple operating system as it does not require a fixed site operating mechanism for the offloading of waste, allowing the truck to go where it needs to go without constraint or delay.

In addition to the two internal truck offloading options (tipped floor and live floor), there is an external mechanism option. These are pre-sighted tipper facilities installed at strategic locations in and around the landfill. The ability to offload large amounts of bulk waste quickly more than compensates for the up-front capital costs required to install a tipper system. 

Tipper systems come in various sizes, from large fixed tippers exerting large amounts of hydraulic force to less powerful (but more operationally flexible) mobile systems. Mobile tippers can be hauled around the landfill and positioned as needed relative to the location of the current working face. And while the capital costs of such a large mechanism may seem prohibitive, in situations where rapid offloading is a necessity the acquisition of a single tipper can be much more cost-effective than out lifting every truck in the hauling fleet with its hydraulic off-loading system. 

So which system is best? According to Charlie Benton, Product Manager for Refuse Trailers of East Manufacturing Corporation, there are no one-size-fits-all solutions: “Generally, the moving floor is ideal for areas where self-unloading is preferred, areas not dependent on a separate means of unloading. The primary advantage of the moving floor is its ability to unload the load anywhere. It is more important than ever when you’re spec’ing your refuse trailer, you’re properly spec’ing the right moving floor to meet your application. First, we need to determine what type of materials you will be hauling. These considerations will help you determine the floor configuration.” 

Each system has its pros and cons. Fixed tippers have the highest overall productivity, but also the highest up-front capital costs (per unit). But they can result in reduced operation flexibility and lower overall site productivity if they are not properly sited or sized. Ironically, their greatest cost savings potential is not at the landfill but within the truck hauling fleet itself by reducing hauling weight loads and eliminating the cost of un-truck hydraulic off-loading systems. 

Live floors, on the other hand, improve safety and operational flexibility, while being more efficient than standard hydraulic jack systems. This avoids the potential for truck queues and indirect improvement in disposal efficiencies as they can place the waste where it is currently needed at the working face. They are also ideal for non-landfill operations such as transfer stations and materials recovery facilities (MRFs) that are enclosed in buildings that don’t allow extensive vertical space. But as with all hydraulic systems, there will be additional maintenance costs required.

Improving Off-Loading Productivity and Safety with Technology  

Safety is not just a result of operation and movement. Leakage of fluids and liquids is also a serious safety concern. In addition to leaks of the hydraulic working fluid itself, municipal solid waste is often inherently wet. MSW, therefore, provides challenges regarding contaminants and hazardous liquids in the trailers. Leak-resistant and leak-proof live floor designs are revolutionizing the industry today. A true leak-proof system must have the working hydraulic drive unit outside of the trailer interior to make for simpler maintenance and longevity of the hydraulic system. 

The next evolution in safety will come from the operator interface perspective. Automated doors, load sensing systems for volumetric measuring, and automated remote controls are going to change the way the live floor trailers operate within the landfill. Keeping drivers safely away from the waste loads unloading is going to become a key focus. The use of automated rear doors, electronic controls, and video systems will change the way a driver controls the unloading of their trailer. Like the system in collection trucks today, transfer trailers will need to be updated to keep up with the demand. Keeping the drivers in the cab is the safest method.  

The more regulations that focus on organic diversion from the wastestream, the greater the demand for leak-proof and leak-resistant trailers will be. The transportation of organics poses a unique challenge for trailer and component manufacturers with regards to containing potential pathogens or acidic liquids during transportation. A drive system located outside the trailer body and above the bottom of the trailer will be the most advantageous to combat this harsh environment. 

Major Suppliers

East Manufacturing Corporation (Randolph, OH), is a leading manufacturer of a full line of aluminum platform, dump and refuse trailers, and steel dump trailers and dump bodies, for the commercial vehicle, construction, agricultural, and refuse markets.

Their standard floors are recommended for solid waste and recyclables. Thicker floors provide the support required for heavier loads like C&D, bulky items, and crushed car scrap. Hauling a combination of solid waste and C&D would require upgrading to a thicker floor. Bulk commodities are best carried in moving floor trailers equipped to maximize the volume of materials being hauled and the ease of unloading over uneven terrain. Moving floor trailers built to be forklift compatible can also be utilized for hauling palletized loads, Gaylord boxes, and super sacks. Moving floors are being used for their backhaul ability. Recyclables and wood products are a typical backhaul load for these trailers. 

Retrofitting the floor requires several steps. The tractor will require a dual-line hydraulic wet kit to operate the moving floor. Durability in the floor depends on its strength, and East Manufacturing provides high-strength floor systems. Many waste haulers specify thicker walls and floors at the last 4 feet of the trailer, providing the best wear factor. It is more important than ever that when specifying a refuse trailer, the right moving floor is specified to meet the application. 

The most critical point in securing East trailer strength is in the advanced wall-to-floor construction—the welded union of cross members, floor plates, and sidewalls. The cross members and floor plates interlock into the bottom rub rail, forming a pocket to accept the sidewall panels, which provides a super-strong floor-to-wall attachment joint. East goes a step further by putting braces on each side of the drive unit for extra strength to prevent bowing of the bottom rails. The result is East provides more profitability with the combination of light weight, strength, and high payload ratings. Also, a driver-side access hole in the bulkhead provides easy access to the stainless-steel tubing. This gives the technicians plenty of space to work on the hydraulics.

Since 1976, Hallco Industries Inc. has been a manufacturer of live floors (a.k.a. “The Original Live Floor TM System”) that allows for the safe and efficient unloading of bulk loads under low overhangs and on uneven or soft ground. Their system allows for the movement of virtually any allowable load weight with a wide variety of widths and lengths. Their live floor can move whole container loads at speeds up to 11 feet per minute. The patented Accelerator Technology on every Hallco I-Series Drive allows for the reconfiguring of a three-step process to a two-step process, speeding up the unload time for most products by up to 30%. Hallco offers a wide array of slat options which can be reconfigured for various products while spreading out the load to form a complete cover over the entire floor and thus limit the potential for load bridging.

Unloading times are determined by the flow of hydraulic oil in gallons per minute (GPM). The optimal system design will utilize 30 GPM at 3,000 psi. Pushing more oil to the system will create a jackhammer effect on the equipment and cause slippage of the floor under the materials being unloaded, diminishing the return of overworking the hydraulic pump on the truck. Instead, look for a system that can utilize a mechanical switch to go from a three-step system to a two-step system, like the Hallco Accelerator technology. 

Design specifics include standard wide slat widths (available with 3 and 5/8-, 3 and 7/8-, or 4-inch-wide slats), with overall decks as wide as the inside dimension of the trailer allows. Most commonly used widths are 82-inch, 87 and 3/4-inch, or 93 and 3/4-inch. Common deck lengths are anything up to 53 feet. Floor thicknesses range from 1/2-inch to 7/8-inch with greater thick decks that are best suited for the solid waste industry to accommodate and withstand the impacts of top-loading of transfer trailers, compactor loading, and high-speed unloading at landfill sites. 1/8-inch or 3/16-inch-thick decks are best for lighter duty applications such as agriculture or wood products. 

Below the slats is an integral feature of the live floor: the subdeck. The Hallco subdeck is available in steel, aluminum tubing, or Hallco’s six-point aluminum extruded profile, 2 inches wide by 1 inch high by .065-inch minimum thickness. Hallco’s 2-inch-wide subdeck provides a 31% improvement of impact strength and gives the bearings and slats ample support, allowing the deck slats to move easily without rocking side to side under the load. 

Keith Manufacturing makes the industry-standard KEITH WALKING FLOOR. In 1973, Keith Manufacturing Co. introduced the first commercially viable moving floor unloading system under the WALKING FLOOR brand name. 

The system serves as the flooring of the trailer and consists of a series of floor slats hydraulically operated by a drive unit underneath the trailer. As the floor slats cycle through a four-phase process, the material is “walked” out of the rear of the trailer. The trailers are not as susceptible to unloading interruptio