A recycler in Poland called me about a shredder that was “underperforming.” They were feeding 200-litre HDPE drums and getting about a third of the throughput the brochure promised. They wanted to know if the motor was undersized.
I asked two questions. How much does one of those drums weigh? He said about nine kilos. Second question: how many can you fit in the hopper at once? He said two, maybe three.
There was the answer. Nine kilos per drum, three in the hopper — that is 27 kg of plastic in a machine sized to move hundreds of kilos an hour. The motor was fine. The machine was spending most of its time waiting for the next barrel to fall in.
The short answer
Drums and barrels are not a hardness problem. They are a volume problem. A 200 L drum is mostly air. It fills the hopper, weighs almost nothing, and on impact it can bounce instead of being grabbed. So the number that matters is not kilograms per hour — it is how many drums you can get into the chamber per hour, and that is set by hopper size and feed opening, not motor power.
Two things decide whether a machine can take whole barrels:
- Hopper opening — can the barrel physically go in?
- Feed width at the rotor — can the rotor actually grab it once it is in?
Most people check neither. They check kilowatts.
The drum is mostly air
This is the part that misleads everyone.
| Container | Typical size | Empty weight | Material per unit volume |
|---|---|---|---|
| 20–25 L jerrycan | ~290 × 250 × 400 mm | 1.2–1.5 kg | Bajo |
| 60 L drum | ~Ø400 × 650 mm | 3–4 kg | Bajo |
| 200 L HDPE drum | ~Ø580 × 900 mm | 8–10.5 kg | Muy bajo |
| 1000 L IBC tote | 1200 × 1000 × 1150 mm | 55–65 kg | Very low (metal cage excepted) |
A 200 L drum has a wall thickness around 2–4 mm. Cut it open and flatten it and you have a sheet maybe 900 × 1800 mm — a few kilos of HDPE spread over a lot of area. The drum is a container, not a lump of plastic.
That is why the throughput in kg/h looks so poor when someone tests your machine with barrels. The machine is doing exactly what it was built to do. You are feeding it air with a thin skin of plastic around it.
On hollow parts, the hopper is the bottleneck, not the rotor. Count containers per hour, not kilos.
Does the barrel actually fit? Two numbers to check
This is where I see machines get bought wrong. There are two separate openings and both have to work.
1. Hopper opening
The opening has to accept the barrel in whatever orientation it will actually land in. Our SC series hoppers are:
| Modelo | Hopper opening |
|---|---|
| SC600 | 800 × 500 mm |
| SC800 | 850 × 630 mm |
A 200 L drum is about Ø580 mm. Against a 500 mm dimension on the SC600, it does not fit in either orientation — 580 mm is bigger than 500 mm whether you stand it up or lay it down. On the SC800 the 630 mm dimension clears 580 mm, so a whole drum goes in.
2. Feed width at the rotor
The rotor has a working width, and the usable intake is roughly rotor width minus 100 mm. From the S Series:
| Modelo | Rotor width | Usable intake |
|---|---|---|
| S600 | 600 mm | ~500 mm |
| S800 | 820 mm | ~720 mm |
| S1000 | 1030 mm | ~930 mm |
| S1200 | 1230 mm | ~1130 mm |
| S1400 | 1450 mm | ~1350 mm |
| S1600 | 1650 mm | ~1550 mm |
| S1800 | 1850 mm | ~1750 mm |
Same conclusion from the other direction. A Ø580 mm drum against an S600 with ~500 mm of usable intake will not be grabbed cleanly. Move to the S800 with ~720 mm and it drops straight in.
Both numbers point at the same answer, which is what makes it trustworthy. If you are feeding 200 L drums, the SC600 and S600 are the wrong size and the SC800 / S800 class is the starting point. If you are feeding IBC totes at 1200 × 1000 × 1150 mm, no standard single shaft shredder takes that whole — those get dismantled first.
The safety step people skip
Sealed drums can hold pressure, liquid, or both. Putting one into a shredding chamber is how people get hurt, and it is also how you destroy a set of knives.
Before a drum goes anywhere near a rotor:
- Check what was in it. Not what the label says — what is actually in there. Pharmaceutical, agrochemical and solvent residues are the ones that bite.
- Drain it. Completely. Residual liquid turns your shred into hazardous waste and ruins the regrind.
- Vent or open it. A sealed container that gets crushed by a rotor at 73 rpm with tens of kilowatts behind it will let go. Cut or puncture it first.
- Strip the metal. IBC cages, drum lid clamp rings, and steel handles. Steel in a shredder does not get shredded — it takes a chunk out of your rotor knives.
That fourth one is the expensive one. A lid clamp ring is cheap to remove by hand and very expensive to remove from a rotor.
I should also say plainly: if the contents are unknown and you cannot verify them, do not shred it. There is no throughput target that justifies guessing.
Why barrels bounce, and what the pusher is for
A solid lump gets bitten by the rotor on the first pass. A hollow drum often does not. It lands, the rotor hits it, and because there is nothing behind the wall to resist, the whole drum skitters across the top of the rotor instead of being drawn down.
This is exactly what the hydraulic pusher on a single shaft shredder exists to solve. It is not a convenience feature. On hollow parts it is the thing that makes the machine work at all.
Our S Series carries a hydraulic unit at 5.5 kW up to 7.5 kW depending on model, and that is what drives the pusher. When someone tells me their shredder “won’t take drums,” the pusher cycle and its pressure setting is the first thing I look at — before the motor, before the blades.
Related: hollow parts are also the loudest thing you can feed. A sealed drum failing inside the chamber is an impact event, not a cut, and those push a machine from 75–85 dB(A) up past 100 dB(A). If you are running drums, read the noise and dust article — the hopper lid and lined discharge matter more on this material than on any other.
Single shaft or double shaft for drums?
Both work, and they suit different operations.
| Single shaft + pusher | Double shaft | |
|---|---|---|
| How it takes a drum | Pusher forces it onto the rotor | Two rotors grab and pull it through |
| Resultado | More uniform, sized by screen | Coarser, more variable |
| Best for | Barrels you want to size for a crusher or wash line | Very bulky, mixed, or contaminated feed |
| Hollow-part behaviour | Needs pusher pressure set right | Grabs hollow parts more naturally |
| Downstream | Feeds a crusher cleanly | Often needs a second stage |
If you already have, or plan to buy, a crusher for the second stage, the single shaft is the cleaner choice — the screen gives you a predictable ceiling and the crusher does the sizing. If the feed is mixed bulky scrap where drums are one item among many, a double shaft is more forgiving. We wrote that comparison properly in the single vs double shaft article and in the double shaft guide.
What comes out, and why it jams your next machine
Drums shred into curved, springy pieces. They do not pack down. They bridge.
Two consequences worth planning for:
- Bulk density is poor. A bin of shredded drum weighs far less than the same bin of shredded purgings. If your downstream is a conveyor or a metering feeder sized by weight, it will run starved.
- Pieces bridge in hoppers and chutes. Curved fragments interlock and form arches over an outlet. This is the most common cause of “my crusher keeps starving” on a drum line.
The fix on both is to get the material through a second sizing stage rather than trying to handle it as-is. That is where screen choice matters — on hollow parts, running a screen that is too small just re-cuts material that is already small enough, which is the whole argument in the shredder screen size article.
How to estimate throughput on barrels
Do not start from the brochure kg/h figure. Start from the container.
Containers per hour ≈ (chamber intakes per hour) × (containers per intake)
- Containers per intake is set by hopper volume and barrel size — usually 1 to 3 for 200 L drums.
- Chamber intakes per hour is what you have to measure, because it depends on pusher cycle time and how cleanly the rotor grabs. On hollow parts this is where the time goes.
Then sanity-check the result against the machine’s power. If your estimate implies far more kg/h than the motor can process, your intake count is too optimistic. If it implies far less, the hopper or the pusher is your constraint, not the rotor.
That second case is almost always what is happening when someone reports a drum line running slow. The capacity article goes through the same arithmetic in more detail if you want the full method.
Before you buy: seven checks
- Measure your largest container, not the average one. Diameter, height, and whether it still has a lid ring.
- Check the hopper opening against that dimension in both orientations.
- Check rotor width minus 100 mm — that is the usable intake.
- Decide whether whole containers go in, or you pre-cut. Pre-cutting costs labour but lets a smaller machine do the job.
- Confirm what the containers held, and whether they will be drained and vented before they reach you.
- Ask about the metal. Cages, rings, handles. Plan for removal.
- Plan the second stage now. Shredded drum does not flow well; a crusher after the shredder solves bulk density and bridging at the same time.
And if siting is still open, the installation requirements article covers floor space, power and foundation — worth reading before you commit to a machine size.
PREGUNTAS FRECUENTES
Can a plastic shredder take whole 200 L drums?
Yes, if the machine is big enough. A 200 L drum is around Ø580 mm, so you need a hopper opening and a rotor intake comfortably above that. On our range that means the SC800 / S800 class and up; the SC600 and S600 are too small for whole drums.
Why is my shredder slow on barrels?
Almost always hopper volume or pusher behaviour, not motor power. Barrels are mostly air, so the machine waits for material instead of being limited by cutting force.
Do I need to drain drums before shredding?
Yes. Residual liquid contaminates the regrind and can make the output hazardous waste. A sealed container can also fail violently when the rotor crushes it, so drain and vent it first.
Can I shred IBC totes whole?
Not in a standard single shaft shredder. A 1000 L IBC is around 1200 × 1000 × 1150 mm with a steel cage. Remove the cage and cut the bottle down first.
What screen should I use for drums?
Bigger than you think. Hollow parts produce springy, curved pieces, and a small screen just re-cuts material that is already small enough. See the screen size article for how to pick it from the downstream machine.
Single shaft or double shaft for barrels?
Single shaft with a pusher if you want sized output feeding a crusher or wash line. Double shaft if the feed is mixed and bulky and you care less about uniform size.
How much does a shredded drum weigh?
A 200 L HDPE drum is roughly 8–10.5 kg empty. That is the number to plan around, not the 200 litre volume.
Where to go from here
If you are still choosing a machine, start with how to spec a single shaft shredder — hopper opening and rotor width are two of the inputs, and this article is the one that explains why they dominate on hollow feed. For pipe and other long hollow sections, the P Series pipe shredder is built around the same problem.
SLECOTECH (Streamline Eco Tech) designs and manufactures industrial shredders, granulators, washing lines, and complete plastic recycling systems. The company is based in Yuyao, Zhejiang, China, and exports to more than 30 countries. If you send us the container type, its dimensions, what it held and how many per hour you need, we can tell you which model actually takes it — and whether pre-cutting would let you buy a smaller machine.
See the single shaft shredder range or the SC Series integrated unit if you want the shredding and crushing stages on one frame.