Horizontal grinders and tub grinders each offer unique advantages based on a variety of factors, including feedstocks and end product requirements. Learn more about each type below to find out which option is right for your grinding operation!
Types of Tub Grinders
Agricultural tub grinders are designed to process baled and bulk agricultural feedstocks for use as animal feed and animal bedding. Generally smaller and lighter than industrial tub grinders, agricultural tub grinders are typically powered by a tractor PTO or an on-board diesel engine. The basic design has been in use for decades. Industrial tub grinders are designed for wood waste, yard waste, and other feedstocks that need to be reduced in size for use as compost and other products.
Finished Product Control
Industrial tub grinders are mainly used for primary grinding of raw materials and are not capable of efficiently achieving finished product specs from many forms of wood fiber and other raw materials.
Horizontal grinders provide much more control and allow operators to more efficiently achieve small particle sizes required for landscape mulch, animal bedding, and other finished products.
“Perfect In One Pass”
Rotochopper horizontal grinders are widely recognized for superior particle size control. Our commitment to “Perfect In One Pass” innovation allows operators to transform diverse feedstocks into premium colored and natural landscape mulch, animal bedding, and many other uniformly size products.
Tub grinders rely on the force of gravity and tub rotation to regulate feed rates, which means that efficiency can vary drastically based on the consistency of feedstocks. For example, tub grinders can have difficulty feeding lighter materials, like tree limbs, slabs, and corn cobs, which may “float” above the rotor without sufficient weight to force them into the rotor teeth. Subsequently, heavier feedstocks, like bark, dense round bales, and compost, can feed too quickly, causing rotor lugging or even plugging. Because the rotor in a tub grinder is constantly exposed to oncoming feed material, with nothing to hold the material back from the rotor, feedstock can be pulled into the grinding chamber too quickly. Tub grinders may experience extreme fluctuations in horsepower efficiency, as feed material alternates between floating above the rotor and being sucked into the grinding chamber.
Horizontal grinders, however, provide better control over feeding rates because feedstock is delivered into the grinding chamber at a steady speed. The powerfeed drum (feed roll) of a horizontal grinder digs into feed material to provide a level of feed rate control much greater than a tub grinder can achieve. If raw material feeds too quickly, the powerfeed drum and infeed conveyor can be reversed to allow the engine or electric motor to recover.
Rotochopper horizontal grinders feature the most aggressive powerfeed drum design in the industry, providing controlled feed rates for forestry slash, wood chips, pallets, slabs, and a wide range of other feedstocks. Our patented slab ramp allows operators to efficiently process pliable feedstocks that can instantly plug other grinders, such as palm fronds and tomato vines. When equipped with our unique bale pre-processing system, our horizontal grinders offer unmatched efficiency for grinding round bales.
Tub grinders are notorious for hurling objects long distances at considerable speeds. Because the rotor is exposed at the bottom of the tub, a tub grinder can easily throw objects unless the tub is packed with raw material. Some tub grinders incorporate covers or deflectors to minimize the hazard posed by flying debris and thrown objects, yet the occurrence of thrown objects is still greater for tub grinders than other grinding systems.
Horizontal grinders also have inherent safety concerns, including the possibilities of thrown objects. Like tub grinders, horizontal grinders require conscientious, trained operators who always follow safety policies. Horizontal grinders, however, allow operators to more conveniently manage their safety policies by confining the thrown object hazard zone to a much smaller space that extends forward and slightly outward from the feed opening. A horizontal grinder generally will not throw objects nearly as high or far as a tub grinder can because the top portion of the rotor is not exposed, as it is in a tub grinder.
Rotochopper horizontal grinders feature a down-cut rotor design, further limiting the distance that thrown objects may travel. As with all high-speed grinding equipment, the thrown object hazard zone for a Rotochopper grinder requires safety precautions, including the use of enclosed cab loading equipment and personal protective equipment.
As one of the first kinds of equipment capable of processing wood waste and other forms of waste, tub grinders have helped advance the recycling industry. But since the development of horizontal grinders in the early 1990s, tub grinders have been steadily replaced by horizontal grinders because of their superior efficiency, finished product control and increased safety. The “Perfect In One Pass” Rotochopper advantage optimizes these inherent benefits by delivering the results you need from your raw materials at low operating costs.