Two Ways to Remove Water, in a Fixed Order

A washing line does not dry flakes; it washes them, and then two different machines remove the water. The first is mechanical: spin the water off by centrifugal force or squeeze it out by screw pressure. This costs a few kilowatts and no heat. The second is thermal: a dryer that evaporates whatever the mechanical stage left behind, and pays for every kilogram of that water in energy.

The published order matters because the dryer's load is not a property of the material — it is a property of the machine upstream of it. The dewatering page states the link directly: less water carried into the dryer means lower energy cost and higher drying stability. A dryer that receives flake at 3% outlet moisture has a different job, and a different energy bill, from one receiving the same flake at 8%.

So when output moisture runs high, the honest diagnostic sequence starts at the dewatering stage: which structure is installed, what it is published to reach, and whether the material matches the structure. Only then does the dryer enter the conversation.

Two Structures, Because Two Materials Behave Differently

The published dewatering machine range is built around a split that has nothing to do with capacity and everything to do with material form. Rigid flakes and PET regrind behave one way in a spinning chamber; film, woven bags and agricultural film behave in a completely different way.

Vertical (VD) — centrifugal. For PET flakes and rigid regrind, the machine spins the water off at drum speeds published from 1,000 to 1,500 rpm, and reports its performance as a dewatering rate: 95% or higher across the series.

Horizontal (HD) — screw press. For PE/PP film, woven bags and agricultural film, a screw squeezes the water out under pressure, and reports performance as outlet moisture: 3-15% depending on model. The wider band is not a weakness — it reflects a material that carries water in ways a spin drum cannot grip.

The published FAQ answers the obvious follow-up plainly: can one machine do both? It can, but efficiency drops. That is why the split exists. Our earlier post on vertical versus horizontal dewatering walks the structural comparison; the point here is the consequence: putting film through a centrifuge, or flakes through a screw press sized for film, moves moisture problems downstream that were created upstream.

Published Model Data, Both Series

Both series are published model by model. Note that the two tables do not share a column: vertical machines are rated by dewatering rate, horizontal machines by outlet moisture, which rises with throughput on the same model.

Vertical centrifugal — VD series

Horizontal screw press — HD series

Two things are worth reading out of the tables together. First, the horizontal machines' outlet moisture climbs as the model gets bigger and faster: the HD-300 is published at 3-5% while the HD-800 is published at 8-15%. Throughput and dryness trade against each other inside one structure, which is exactly why the dryer must be sized per project rather than assumed. Second, the vertical series holds its ≥95% dewatering rate across the whole capacity range — the physics of spinning rigid flakes scales more cleanly than the physics of squeezing film.

For heavily wetted or irregular material, the page also publishes an inclined configuration to avoid blocking — a reminder that feed behaviour, not just target moisture, shapes the selection.

How the Dryer Gets Sized — and Why Upstream Decides It

The published guidance for when a dryer is needed is unambiguous: if the granulator or the end customer needs moisture below what mechanical dewatering reaches, the dryer is part of the line, and it is sized on the outlet moisture of the dewatering machine. That makes the dewaterer's model choice a dryer-cost decision made months before the dryer is quoted.

On a PET bottle washing line, the published sequence puts dewatering and drying as the final two stages, and the published line data carries outlet moisture as a first-class column next to total power. Flake quality targets such as residual moisture are confirmed after a wash trial on the customer's bales — because the moisture that arrives at the dewaterer depends on the wash, and the wash depends on the bale.

The same logic runs through film lines. A friction washer leaves material wetter than a float tank does; a PP/PE rigid line and a film line do not dry the same way; and every one of those differences lands, eventually, as either mechanical load on the screw press or thermal load in the dryer. The line is a moisture budget, and the dewatering stage is where most of it is spent or saved.

Four Mistakes That Show Up in Moisture Troubleshooting

• Upgrading the dryer before checking the dewaterer. If the installed structure does not match the material — film on a centrifuge, flakes on a screw press — the published efficiency drop lands downstream as wetter feed, and no dryer resize fixes an upstream mismatch economically.
• Reading the two rating systems as one number. A ≥95% dewatering rate and a 3-15% outlet moisture are different metrics for different structures. Comparing them directly, or expecting a screw press to match a centrifuge's dryness on film, misreads both tables.
• Ignoring the throughput-moisture trade on horizontal machines. The same HD series is published from 3-5% to 8-15% outlet moisture as capacity rises. Pushing an HD-300's duty onto an HD-800 does not just change capacity — it changes the moisture the dryer inherits.
• Setting a dryer target below what the material trial supports. The published PET line guidance is explicit that residual moisture targets are confirmed after a wash trial on the customer's bales. Targets set from a brochure instead of a trial tend to be re-negotiated at commissioning.

A fifth case sits between the machines: the wash itself. Water carried out of the wash stage — its temperature, its chemistry, how much clings to the flake surface — is the input the dewatering stage never chose. When moisture runs high, the honest sequence is wash, then dewater, then dryer, in that order.

What to Send With the Enquiry

Both the dewatering page and the washing-line pages close with the same request: send the material and the target. Four inputs turn a moisture complaint into a line specification:

• Material form — rigid flakes, regrind, film, woven bags, agricultural film. This picks the structure before any model number is discussed.
• Throughput — kilograms per hour, honestly stated, because the horizontal tables trade outlet moisture against capacity.
• Target moisture — what the granulator or end customer actually accepts, since that decides whether a dryer exists in the line at all.
• What comes before — wash type and upstream equipment, because the dryer is sized on the dewaterer's outlet, and the dewaterer's load starts in the wash.

Send those four and the published tables do most of the work: VD series where rigid flakes spin dry at ≥95%, HD series where film squeezes down to its published band, and a dryer sized on real outlet moisture instead of guesswork. For everything else, a wash trial on your own material replaces the catalogue ranges with numbers for your yard.

Frequently Asked Questions