Learn what is important when appraising the valuing your used size reduction machinery – be it for selling used granulator systems or just to current attain base value. Our guide is designed to help you identify the key components of the appraisal process, as they pertain to your specific granulator machine.
Understanding the Important Specifications for Granulators
Our size reduction machinery experts check a variety of equipment specifications and machine capabilities when appraising used plastics granulators.
Chamber Dimensions: This is the size of the cutting area of the granulator. Not to be confused with the hopper opening, although usually they are the same size, there can be a difference.
Rotor Design: An open rotor has spaces for material to flow through the cutting chamber. This design better suited for thin walled and bulky parts. The open rotor design allows for more cutting action and airflow. Throughput can be greatly increased.
A closed rotor means that the rotor is solid. There is no space between the rotor for material to fall through. You cannot see the screen from the top of the rotor. This rotor design is typically used for tough materials and thick-walled parts such as HDPE pipe.
A staggered or hog-style rotor is typically has a closed design. The helical design allows for more cuts, but with a smaller engagement area between the knives. This is suited best for the thickest material or purge.
Number of Fly and Bed Knives: The number of fly knives refers to the rotating knives. The more rotating knives the more cuts per revolution, however the more knives you have, the less space there is and may inhibit part feeding.
The Bed Knives refer to the number of stationary blades. Most machines with have 2 bed knives, some 3 or more. Same as above, the more knives, the more cuts, but the less space for parts to drop into the bite zone.
Chamber Shape: A tangential granulator chamber is used to allow more space for large parts to enter the cutting area. Tangential granulators are typically used in the blow molding industries, for bottles, or other bulky parts
A direct fed is used typically for thicker parts. The advantage to this type of feed is that it limits the amount of part that will be cut at one time.
Screen Size: The size of the screen will determine the finished partial size of the regrind. Typical screen sizes in a granulator system are .25”-1” with the most common being 3/8”. The smaller the screen size the less output the system will have.
Serviceability Features: Hopper tilt is one of the most common granulator features. This allows the user to tilt back the hopper without having to completely unbolt and remove in order to service the granulator blades. Most often granulator hopper tilt has an arm that in pneumatically actuated or with a screw jack.
On larger machines the screen cradle or chamber itself can also have this type of feature to make it easier to service.
Discharge Type: There a few ways to get the material out of the granulator.
Airveyor (with blower and cyclone) - This always continuous evacuation. Material is pulled through the blower into a cyclone and then drops into a gaylord. Dust collection can be integrated into this system.
Bin Discharge - The material is collected in a bin under the granulator. In low output operations the bin is just removed and dumped when full. In high output operations the bin can be connected to a vacuum system to be evacuated.
Ready for An Appraisal of Your Used Granulator?
When you’re ready to sell your granulator, or simply for appraised value, contact us to learn more about our valuation process or to schedule an appraisal. You can begin by collecting equipment specifications pertinent to your specific granulator with our Granulator Specs Form.