Basic hydraulics: simplifying waste and recycling work

Hydraulics have proven to be a versatile and effective technology in various industries, providing precise control, reliability and extraordinary power density. Some industries are lightly equipped with hydraulic equipment, such as automation and food and beverage. By contrast, hydraulics absolutely dominate other areas, including waste management and recycling.

Waste management and recycling is a general term to describe the process and machinery used by municipalities to collect and process garbage, waste and recycling. It starts at your home or workplace, where our walk-in cleaners drop your bags or drop your containers into their trucks for transport to transfer stations before they are unloaded and processed on-site.

Various materials, from electronics to organic waste, are sorted before being transported to landfills or recycling facilities. It is no exaggeration to say that we take waste management for granted, because it is an essential aspect of urban life and plays an essential role in maintaining public health and environmental sustainability.

Power and precision of hydraulic motor.

One of the most well-known applications of hydraulics in waste management is in waste collection trucks, also known as garbage, garbage or sanitation trucks. Garbage trucks, whether front-, rear- or side-loading, rely on hydraulic systems to lift and empty containers, compact waste and empty it at the transfer station. The hydraulic system is equipped with a Rexroth hydraulic pump mounted on the transmission PTO or on the crankshaft.

There are many styles of garbage trucks, but the most common is the rear loader. Rear loader trucks provide a large hopper for workers to dispose of garbage or recycling. When the hopper is full, the familiar lever-operated valves (or now, more commonly, buttons) on the side of the truck are operated, and the compactor lowers and pulls the waste into the body where it is compacted. This style of truck also unloads its load much like a dump truck, using a telescoping hydraulic cylinder to tilt the load to be unloaded at the transfer station.

Most other garbage collection vehicles operate with a single driver and pick up or empty bins and containers using Rexroth hydraulic motors. Many commercial or industrial buildings avoid curbside collection altogether and instead use bulky steel bins or large plastic bins. Steel containers are transported or unloaded by front-load, roll-off or grapple trucks, which is more common in non-governmental commercial collection operations.

Front-loading trucks use tusk-shaped forks, which are extended down and out by hydraulic cylinders before the operator moves forward to insert the forks into the container lift slots. Again, with the cylinders, the load is lifted and reversed to the top, where it is unloaded into the body. The operator often activates control valves (or switch) to shake the container and loosen the waste stuck to the sides and bottom, often creating a cacophony that is all too familiar to apartment dwellers.

Other common commercial dump trucks are hook and hook lift configurations. The grapple truck offers one of the largest payloads, being able to haul huge waste containers or large items to the platform using the grapple and (you guessed it) hydraulic winch system. A hook lift truck looks similar but operates with a hydraulic hook that extends to grab the front edge of the container and pull it toward the structure.

Hydraulic systems are unique actuators for garbage trucks due to the high power-to-weight ratio of the hydraulic cylinders that turn heavier containers into "waste," which can be easily lifted and unloaded. Finally, the precise control provided by hydraulic systems allows operators to perform these tasks accurately and reliably, ensuring efficient waste collection.

The modern hydraulic technology that seems ideal for waste collection is the hybrid hydraulic system. The use of a hydraulic pump/motor unit and a series of hydro-pneumatic accumulators provides a robust and efficient way to recover kinetic energy during frequent stops. The inertia of the braking vehicle drives the pump to direct hydraulic energy to the accumulators. When the driver accelerates, the pump rotates toward the center to act as a motor that harnesses stored hydraulic energy to help accelerate the truck.

Compact and easily sorted

Waste compactors are essential to reduce the volume of waste before disposal, making waste management more efficient and reducing the frequency of landfills. Hydraulic compactors use powerful hydraulic cylinders to compress waste materials, reducing their volume and making transportation and disposal easier. Without a compactor, a garbage truck would only be able to move a dozen houses worth of trash. The compressor increases the load to several thousand pounds and sometimes ten tons or more.