Horizontal balers with automatic binding or so-called channel presses are designed to reduce the volume of various materials. All considerations about the performance of this equipment must be made from the perspective of the specific weight of the packaged materials and the amount of material to be compacted in the unit of time. If for bulk PET bottle waste we are talking about a specific weight of 25-35 kg / m3, paper waste has a specific weight of 100-150 kg / m3 and urban solid waste has a specific weight of 250-350 kg / m3. Therefore a 40 m3 container contains 1-1.2 t of PET or 10-14 t of urban solid waste. In an operating cycle, the ram of such equipment has a fixed round trip, so it compacts the same volume. For proper operation, this volume must be optimal “filled” with the material to be compacted. Filling this volume is done in most cases with belt or chain conveyors. It is obvious that the performance of a baler is directly influenced by the ability of the feed conveyor to optimally “fill” the bunker of the press it serves. To make sure that the “filling” of this equipment is optimal, some manufacturers of horizontal balers with automatic binding, such as Macpresse, are also manufacturers of feeding conveyors in a sufficient range to meet customer needs.

We should actually talk about an ensemble: the baler – the feeding conveyor. Returning to performance: the baler-feeding conveyor assembly must ensure a high degree of compaction of the bales (high specific weight), a high productivity (high number of bales per unit of time), a high reliability (especially in the case of in which they are part of an automatic sorting line), low operational costs (low energy consumption per ton baled, maintenance and repairs planned, long service life), maintaining performance over time, to provide information on the state of operation, production , consumables etc. It is important to keep in mind that a press that is integrated into an operating line, such as waste sorting stations, must have higher performance (reliability, speed, easy maintenance, performance retention over time, information provided) by a supermarket press.

In the case of waste sorting stations with a high degree of automation, the performances required of the baler-feed conveyor assembly are even higher. Also, urban solid waste balers are special presses, different from recyclable waste balers.

For example, a Macpresse Mac 110L press (Fig.1), which has a baling capacity of 35 t/hour of urban solid waste, produces bales of 1.1 × 1.1 × 2 m of 2 t, reducing them 4 times the volume. The costs are also reduced by the considerable decrease of the handling / loading / unloading time which, both at the baling place and at the landfill. To increase the service life, Macpresse shields the press chamber with HARDOX wear-resistant alloy plates, easy to replace. For special applications (for example, baling combustible waste), Macpresse has the option of tying bales with plastic wire, not just metal wire. Binding with plastic wire has the advantages that: it does not rust, the plastic wire is combustible, the bale unfolds easily by cutting the plastic wire, it consumes less than the metal wire, the rollers are easier to handle. After baling, there is the option of automatically wrapping the bales in plastic foil. The bales can be wrapped in plastic wrap with a Rotowrap wrapper, from PTF Häusser Germany (Fig. 2).

The advantages of wrapping the bales in plastic foil are: the sealing is hermetic, the putrefaction processes being interrupted and the bale can be reopened after a period of time in order to sort the valuable materials; the transport is done with normal means of transport (not specialized for the transport of urban solid waste); the bales do not emit an unpleasant odor; they no longer attract birds.

Macpresse Italia offers balers with automatic binding with a capacity of up to 60 t / h. The MAC 106 press (Fig. 3) is an example of a very versatile press. It can be used both in recyclable waste collection centers and in urban solid waste sorting stations. MAC 106 has HARDOX armor, has HxL channel section of 750 × 1100 mm, power hopper section of 1700 × 1020 mm, 4 connections, main engine power 45 kW, pressing force 75 tf, 6 cycles per minute, capacity 508 m3 / hour, productivity for material with a specific weight of 35 kg / m3 of 8.5 t / hour.