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Custom Baling of
Industrial and Recycled Material

Discussion

The following contains material that requires more critical analysis but is a starting point for discussion.

Reasons why I believe that this technique will in time, lead a reduced cost per ton to bale.

Potential output from realistic improvements to the loading, tieing and bale extraction techniques. The resulting costs reflect the difference in volume from less than a days work to several days work.

Product
No. bales / hour
Avg kg / bale
Tons / hour
Cost / T
@ $200 / hour
Cost / T
@ $150 / hour
Newsprint
6
1400
8.4
24
18
Cardboard
4
1250
5
40
30
Soft plastic
4
1300
5.2
38.5
29
Tyres
3
2000
6
33
25
 

This is based on current hydraulic speeds. Increased hydraulic speed is quite basic but to benefit would require improved loading techniques that are at this stage quite difficult to envisage.

Other reasons leading to reduced cost.

Reduced energy requirement because pressure peaks on average just two times per bale ie. one pressure peak per 600kg.

Squeezing from both ends introduces significant new pressures over and above the friction losses of pressing from one end.

In a large centralized stationery baling operation, the cost of delivering and operating the facility could be as much as the baling cost.

 

Compacting tyres
The red area compacted to just 12 bales

 

Discussion

To appreciate the advantage of this technique, you need to understand what happens with the traditional technique with the plunger and either, the friction chamber or fixed chamber. As the feed rate increases, (speed/slice size) there is a disproportionate increase in energy requirement, maintenance requirement as well as reduced density performance.

With the X Press technique of squeezing from both ends, we can see that maximum initial pressures reaching the opposing platen are at best 60-65% but often as low as 40-50% but more importantly what we also see is a time factor. Even in the most crushable materials like cardboard, through the final stages of density increase, there is increasing resistance to speed.

Static pressure (sustained pressure) is more effective in all materials (to varying degrees) than the more dynamic and indirect pressures of the traditional plunger and friction chamber.

I have no hard evidence to support whether speed is a big effect or a small effect. The greater the direct pressure, the greater the indirect pressure via chamber friction. It is particularly noticeable on a bale that has been left in over night.

Bigger slice size means more opportunity for material to move into areas of less resistance during the compression period. Generally, if material is compressed lengthways only;

  1. Density will be more even.
  2. The bale will only want to grow lengthways
  3. There will be fewer bulges.

However, this will be dependent on initial material having a relatively mixed orientation (ie not stratified / layers) this will always be a problem and simply requires better preparation.

Reduced maintenance/increased life expectancy has more to do with the stresses resulting from pressure increase/decrease on hydraulic equipment and construction than any other connection to output.

 

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