Pellet retention system, slotted bucket C3, Ø 395 mm at 575 mm depth

The wide form at full depth

C3 is the widest bucket in the range at Ø 395 mm and uses close to the full depth at 575 mm. It suits gully pots that were built generously in both directions, which on industrial sites usually means a main yard drain or a gully on a route that takes heavy vehicles.

The wide diameter does something worth naming: it spreads the inflow over a larger textile area. For a given volume of water, a wider insert loads more evenly than a narrow deep one, and even loading is what keeps a textile filter passing water.

C3 or D1? Same diameter, different depth

The other comparison in this family, and this one is a genuine choice rather than a fitting constraint.

Both fit the same pot diameter. Where the pot has 575 mm of clear depth, C3 gives you 75 per cent more capacity for the same footprint. Where it does not, or where the weight of a full bucket at extraction is a concern, D1 is the sensible form.

Technical data

Regulatory context. EU Regulation 2025/2365 sets obligations for operators handling plastic pellets, and Operation Clean Sweep is a voluntary industry programme. A retention system can support the measures a site puts in place. It does not, on its own, make a site compliant with either, and WINKLER does not certify compliance. What a scheme achieves depends on the full set of measures, the maintenance regime and the documentation behind it. Background is set out in the guide.

Questions about the C3 form

How do I choose between C3 and A4?

By what fits. Both hold around 70 l. C3 is 10 mm wider and 25 mm shorter. Measure the pot.

Does the wide diameter help with flow?

It spreads the inflow over more textile area, which helps the insert load evenly. It is not a throughput guarantee: flow through any of these systems falls as the insert loads.

What is the weight of a full bucket?

That depends entirely on what is in it. Pellets are light, wet sediment is not. Where a gully collects both, plan the extraction method for the sediment case rather than the pellet case.