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Ballistic Separator

The ballistic separator performs an effective separation of waste according to different physical characteristics. This separation, known as gravimetric, is one of the main tasks before sending the waste to the manual/automatic sorting phase. The ballistic separator classifies the flow of material into three fractions: heavy and rolling fraction (called 3D), flat and light fraction (called 2D) and the sieved fraction (or underscreen fine fraction).

The types of waste that can be screened with the ballistic separator are numerous: lightweight packaging, paper/cardboard, foil and plastic containers, commercial and industrial waste (C&I), municipal solid waste (MSW), waste from construction and demolition (C&D)… Hence, the output flows of a ballistic separator are:

  • heavy and rolling fraction, 3D: flacons and plastic bottles (PET and polyethylene HD), cans, wood, stones…
  • flat and light fraction, 2D: envelopes, trays and plastic film (polyethylene LD), textiles, paper and cardboard…
  • sieved fraction: depending on the size of the holes of the grids on the screening paddles it possible to classify different sizes of underscreen fraction. This fraction, typically not recoverable, has dimensions approximately of 40-50 mm and it contains soil, sand, organic waste and small pieces of recyclables.

Our Company, with the experience of more than 90 machines installed around the world, has over time refined the design and the construction system of  the ballistic separator, integrating it with accessories such as rear fans and automatic variation of the inclination, that allow to reach very high separation efficiencies. All components of the ballistic separator of Parini srl, from shafts made with CNC machines to carpentry, are manufactured and assembled in our workshop in Albinea (RE). All the commercial components of the ballistic separator, from the bearings to the gear-motors, are of the highest quality, made by reliable European manufacturers with service centers all over the world. The main key strengths of the Parini srl ballistic separator are:


Waste separation efficiency higher than 95%

High shaking of waste leads to separation of grouped materials

Settings “on-the-fly”, without stopping the machine and the line

Ratio between maintenance costs and tons of selected material (€/t) among the lowest in the market


Retractable walkways for easy cleaning and maintenance in safety conditions

Heavy series roller bearings of the highest quality

Comfortable, easy to access and protected from dirt greasing points

No vibrations thanks to the use of rubber silent block


Crankshafts in operation for over 30,000 hours

Robust modular eccentric shaft made of hardened high-alloy steel

Each module of the shaft (1 every 4 paddles) weighs 300 kg

High quality Europeans commercial components


Standardized and modular components and parts

Spare parts always available on stock

Constant technical support from design to start-up to operation

Technical team always available for immediate interventions to minimize downtime

Working Principle

The ballistic separator, or ballistic sieve, is composed of a series of parallel paddles (from 4 to 16, depending on the flow of the incoming material), with orbital motion, arranged with a variable angle with respect to the horizontal (from 11° to 20°).

The multiple paddles submit the mass of the incoming waste to a strong shaking, more than solutions with a single screen deck, making the waste separation more effective. The materials feeded into the ballistic separator, having different physical characteristics (weight, shape, surface…), assume different trajectories following the orbital movement of the paddles. Are thus conveyed towards the top of the ballistic separator lightweight and flat materials (2D), while towards the bottom converge the heavy and rolling materials (3D). Along the way, thanks to the continuous shaking of the material, you also get a screening of the powders and the fine fraction through the perforated surface of the paddles. The perforated part of the blade is interchangeable and sized according to the desired sizes of the sieved fraction.

working principle of ballistic separator

A rapid adjustment of the angle of incidence of the paddles allows to increase the amount of the heavy or light fraction sieved in case of change of the processed material. In our ballistic separator only the set of blades tilts, while the chassis and the underlying hoppers remain fixed. This prevents dispersion of dust that other systems are not able to avoid.


The ballistic separators are divided according to the number of paddles, which determines the screening surface and the flow of material processed from the separator.

  • 4 Paddles: is the smallest model of ballistic separator produced by Parini srl. It can be used in small plants or, in combination with the air separator, to increase the quality of the selection.
  • 8 Paddles: intermediate model that can also be supplied in the version with the oversized paddles, to increase the screening surface while keeping the same number of paddles and slightly increasing the overall dimensions. The functions that this machine can perform  are many, from the selection of cardboard > A4 to the separation between bottles (3D) and film (2D) in the plastic flow.
  • 12 Paddles: model designed to meet the needs of waste sorting plants with considerable flow rates; available both with standard and oversized paddlese, the latter leads to a machine with an internal working width ≈ 4300 mm and a screening surface of ≈ 24 m2.
  • 16 Paddles: is the largest model of ballistic separator produced by Parini srl and one of the largest ballistic separators in the world market. To meet the demands of systems with increasing flow rates (50+ t/h sorting lines), Parini srl provides a ballistic separator with 16 oversized paddles, a separator with an internal width of almost 6 meters and a screening area of ≈ 32 m2.

For a first indication of most suitable model for each application, the following table may help; knowing the input flow rate and the density of the material to be treated, the table returns the ballistic separator model most suitable for the application.

Parini srl Ballistic Separator Models

ballistic separator models
*1 L = length of the machine body, without fans or winches. This measure can be changed, by changing the 2D discharge hopper, according to the maximum size of the light fraction (large cardoards, plastic films).
W = width of the machine body, without motor or winches. This measure can not be changed, since it is linked to the construction of the crankshaft.
H = height of the machine body, feeding hopper included. This measure may be changed, depending on the feeding system chosen. Usually it ranges from 3.000 to 3.800 mm.
*2 The power installed is referred to the main motor, connected with the crankshaft.
*3 These are indicative figures. Higher or lower production rates might be obtained depending on the density of the materials to be screened and on the way of feeding the machine.
*4 These models can be transported mounted on trucks. In this way the installation time on site is drastically reduced.

Equipment and Accessories

The ballistic separator Parini srl, in all models, is always equipped with the following standard equipment:

  • automatic tilting system that allows to change the inclination of the screen surface by means of an electric motor, also during operation, in order to adapt the degree of separation at the input material;
  • automatic control of the degree of inclination, to avoid to exceed the allowable range (usually 11-20°);
  • two (or three, depending on the model) variable speed rear fans that help the light fraction (2D) to advance on the screening surface, increasing the productivity;
  • two inspection and maintenance walkways operated by winches: thanks to these two moving walkways the area of the crankshafts is within easy and safe reach for cleaning and maintenance;
  • commercial components (from the gearbox to the bearings) of the highest quality, reliable European manufacturers with service centers around the world;
  • top cover in bolted plates or in retractable fireproof PVC tarpaulin;
  • two doors with sight glass, one in front and one on the rear.

Since the phases of 3D design, construction and assembly of the ballistic separator are entirely carried out in our workshop, accessories/changes that we can offer are several. Below is a partial list of the main ones:

  • motorized inspection walkways instead of manual winch, an electric motor is used to lift/lower walkways automatically;
  • realization of customized screening surface (with grid, with angular, adjustable grid, anti-wear …);
  • top cover sliding doors;
  • interior lighting system;
  • mechanical torque limiter;
  • longer sieving paddles: allowing a greater permanence of the material on the paddles, is possible to reach a better degree of sieving with equal hourly production;
  • shipping of the machine fully assembled: thanks to the compact design the lateral dimensions of the machine are under 3 m (for ballistic separators up to 8 blades). In this way the installation of the machine is reduced to the placement and the electrical connection (a few hours);
  • inverters and electrical panel;
  • changes to the front/rear walls according to the interfacing of the ballistic separator with machines upstream and downstream;
  • conveyors for loading and unloading the ballistic separator and related hoppers;
  • support steel structure, perimeter walkways and stairs;
  • greasing kit: in order to speed up the periodic operation of greasing we can supply air operated pumps complete with the grease drum.
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