One Envelope, Four Different Lines

Here is the published series, reproduced as it appears on the PET bottle washing line page.

Identical rows appear on the film and flexible plastic line, the PP food container line and the appliance plastics line. That is not lazy publishing. It is a statement about what the figures mean: the utility envelope is indexed to capacity, not to polymer. A 1,000 kg/h line needs its transformer, its water main and its drain regardless of whether the feed is bottles, film or shredded housings.

What changes between those pages is the sequence and the machines inside the budget. The PET page puts de-labeling ahead of crushing so glue never reaches the wash bath. The film page replaces the crusher with wet size reduction and adds anti-wrapping feed and squeezing. The appliance page adds metal removal ahead of crushing as standard. Same four rows, different invoices. The film page also notes that film is sized by wet throughput, so the same model handles fewer kilograms than of rigid scrap — the envelope holds, the capacity column shifts down.

Installed Power Is Not Running Load

Take the 120-180 kW row. It is the sum of the nameplates of every motor on that line: the crusher rotor, the friction washer, the dewatering machine, spray pumps, the air-separator fan, conveyors and controls. It is a connection figure, the number your electrician needs to size cable, switchgear and transformer. It is not a meter reading, and treating it as one is the most common error in plant planning.

Three things separate the two. Simultaneous full load is rare: the crusher draws according to what is in its chamber, the dewatering machine follows the flake it receives, and the air-separator fan runs against dampers rather than wide open. The easiest stage to modulate is the FW series, where rotation speed is adjustable by frequency converter on every model. And motors are selected with margin: a motor at part load draws part load.

The consequence runs both ways. Size the supply from the installed figure with a documented diversity factor, or you trip on a cold start with a full chamber. Do not size the operating budget from it, or your cost model overstates electricity and understates everything else. Ask for the motor list: model, kW, and which ones start together.

Auditing the Total Against the Machines Inside

The published machine tables let you check the envelope yourself. Take a conventional rigid-plastic sequence — size reduction, crushing, washing, dewatering — and add the published kW of models that fit the same capacity:

The sums are arithmetic on published cells, and the point is that they land inside the envelope rather than near it. On WL-500 the four machines take 66.5 of the 80-120 kW, leaving room for spray pumps, the air-separator fan and conveyors. On WL-2000 the train takes 215 kW and leaves up to 35 kW for auxiliaries and the dryer. On WL-5000 the same four machines consume the entire 250 kW floor of a 250-300 kW envelope, which is a useful warning: at that size, if the feed needs primary shredding in scope, the auxiliary budget is gone and a different configuration or a larger row is the answer.

This is why the column is worth checking against a quotation. If a supplier quotes 180-250 kW for a 2,000 kg/h line and hands you a motor list summing 320 kW, one of the two numbers is wrong — either the envelope belongs to a smaller row, or the list includes something the envelope never covered. The same logic works on capacity, the interface our crusher-to-washer article treats in detail.

What a Kilowatt-Hour Buys Per Kilogram

Divide the two columns across the range and something useful appears. On WL-500, 80-120 kW over 500-800 kg/h works out to roughly 0.10-0.24 kWh per kilogram. On WL-5000, 250-300 kW over 3,000-5,000 kg/h works out to roughly 0.05-0.10. Specific energy falls by half to two-thirds as the line grows, while the envelope grows only about threefold.

The reason is structural: a large share of a washing line's installed power is not proportional to throughput at all. Pumps, fans, controls, the spray circuit and the water treatment plant are sized to the line, not to the tonnage moving through it, so their cost per kilogram drops as tonnage rises. This is the quiet argument for one 2,000 kg/h line over three 600 kg/h lines, and it is worth stating plainly in a business case that otherwise compares only machine prices.

The counterweight: electricity is usually not the largest operating line, and the avoidable share sits in drying. A line that reaches the dryer carrying water pays twice. The 2% outlet moisture in the same table is a line result, not a dryer guarantee — our moisture article covers where that water is actually removed, and our energy cost article covers the wider levers.

Water: 3 to 20 Tonnes an Hour, and Where It Goes

The water column runs from 3-5 t/h on WL-500 to 12-20 t/h on WL-5000, and the friction washer alone accounts for 2-4 t/h on FW-500 up to 8-12 t/h on FW-1200 — the spray bars that rinse off what friction has just lifted. Expressed per kilogram of product, the smaller line spends roughly 3.75-10 litres per kilogram and the largest roughly 2.4-6.7, so water efficiency improves with scale for the same structural reason as electricity.

Two design consequences follow. The PET page's own FAQ states that the series runs a closed-loop water system including treatment, so the t/h figure sizes your supply, circulation and treatment capacity rather than your mains consumption — a distinction that changes the plant's water permit conversation entirely. And water and air are coupled: the WX air separator page notes that moisture above roughly 10% makes particles stick and reduces separation efficiency. A dewatering stage that is undersized does not only cost drying energy; it degrades the dry separation downstream, which is a utilities problem showing up as a sorting complaint.

What the Envelope Does Not Cover

Read the two published columns as the electrical and hydraulic envelope of the mechanical line. Four loads sit outside them and each one has to be brought in deliberately.

Heat. The PP food container page states that hot-wash temperature, dosing and odour-control scope are set per project and remain to be confirmed until material is tested. Thermal energy is not in the electrical column and cannot be estimated from a polymer name.

Drying. Outlet moisture of 2% or lower is the line target after dewatering and drying; where the thermal stage sits in the sequence and what it draws is fixed with the project, not read from the row.

Site loads. Compressed air, lighting, water treatment and civil loads are separate budgets, and in a small plant they are not trivial against a 120 kW line.

Site conditions. Altitude, ambient temperature and supply voltage derate motors and change starting arrangements. These belong in the electrical design, not in a table cell.

The Numbers to Hand Your Electrician

Before any of this becomes a purchase order, five items should be on one page:

• Installed power and the motor list. Not just the row total: every motor, its kW, and which ones start simultaneously.
• Diversity and starting method. What the supplier assumes about simultaneous load, and which motors are on frequency converters or soft starters.
• The water figure split into supply, circulation and make-up. Closed loop with treatment changes the permit and the pump sizing, not just the bill.
• Heat and drying scope in writing. Whether hot wash and thermal drying are inside the quoted envelope or quoted separately; the line table does not decide this.
• Which machines the envelope assumes. One crushing stage or two, primary shredding in scope or not. That single question moved the WL-5000 audit to the ceiling of its row.

Answer those and the table becomes a design document: the row you choose tells your electrician what to build, your water engineer what to supply, and your accountant what the line costs per tonne — three conversations much cheaper before the concrete is poured.

Frequently Asked Questions