Packaging waste shredding is necessary to reduce the volume of packaging or to carry out operations to separate the heterogeneous materials that make up the packaging.
Crushing and volumetric reduction of packaging is achieved by the use of:
-Double-shaft shredders capable of performing a primary shredding of materials. These are industrial shredders made with two shafts on which are mounted rotating blades. The twin-shaft, primary shredders have no classifier screen and the size of the output material is determined by the thickness of the cutting blades. The main purpose of the double-shaft shredder is to operate a first volumetric reduction so the control of the output size is a secondary element. The two-shaft shredders are very efficient in the volumetric reduction of bulky packaging such as drums, jars of different sizes, generic and similar containers. The double shaft shredders for bulky waste are generally made with electric traction system and equipped with two motors with power ranging from 11 to over 150 kw. All industrial twin-shaft shredders are made with a pair of independent gearboxes to avoid overloading the reduction systems and to allow the variation of the speed of the axes as a function of the materials to be treated.
-Single-shaft shredders are used for the second size reduction after twin-shaft shredder. The single-shaft shredders are designed to equip with a classifier screen of different sizes for an effective control of the size of the output material. The use of the primary single-shaft shredders is particularly suitable in cases where the materials in output, of the desired size, They shall be initiated into subsequent separation operations by mechanical systems such as densimetric separation table or vibrating sieves.
-Packaging granulation is useful when a reduction in the poly-coupled materials that are used for food packaging such as Tetra Pak ( source: http://www.thyristorcyclo.it/come-and-done/ )"Tetra Pak containers are suitable for the storage of both fresh foods that require refrigeration and long-life foods, thanks to aseptic packaging. Containers suitable for short-term storage of fresh or pasteurised products, which must be stored refrigerated, shall consist only of paper and polyethylene. The long-life products, thanks to aseptic packaging can be kept for a long time at room temperature, without the need for preservatives". Tetra Pak consists of 74% paper, 21% polyethylene and 5% aluminium. For a separation of the materials that make up the polycoupled granulation must be very fine to allow the separation of heterogeneous parts that will then be separated with the use of densimetric tables, vibrating sieves or electrostatic separators.
The following is a classification of packaging as indicated by the National Packaging Consortium
Source Conai https://www.conai.org/imprese/cosa-e-packaging/
a. packaging means the product, consisting of materials of all kinds, intended to contain certain goods, from raw materials to finished products, to protect them, to enable them to be handled and delivered by the producer to the consumer or user, to ensure their presentation, as well as disposable items used for the same purpose;
b. sales packaging or primary packaging means packaging designed to constitute, at the point of sale, a sales unit for the end user or consumer;
c. Multiple or secondary packaging: packaging which is designed to constitute, at the point of sale, the grouping together of a number of sales units, irrespective of whether it is sold as such to the end-user or to the consumer, or that only serves to facilitate the supply of shelves at the point of sale. It may be removed from the product without altering its characteristics;
d. transport packaging or tertiary packaging: packaging designed to facilitate the handling and transport of goods, from raw materials to finished products, a number of sales units or multiple packages to prevent their handling and transport related damage, excluding road, rail, sea and air containers".
The double-shaft shredders and single-shaft shredders of the Stokkermill series are able to shred bulky packaging waste. Below is a list of some of the possible applications.