Centrifuge Filter Bag, 25 Micron, for Finer Solids Retention

When a finer centrifuge filter bag is the right answer

The trigger is usually the same. Solids are turning up in the filtrate that should have stayed in the basket. Either they block downstream equipment, or they are lost product.

That is what this version is for. As an industrial centrifuge filter bag at the finer end of this range, it retains smaller solids than the high-throughput version does.

The price for that is the usual one. A denser filter medium lets liquid through more slowly. If your bottleneck is cycle time rather than retention, this direction will not help.

What the 25 micron figure means

The 25 micron describes the grade of the filter material fitted. It is not a tested separation limit for the finished assembly in a running process.

What is actually retained depends as well on particle shape, particle distribution, the medium, the load, the speed, and on whether a solids layer builds up in the basket. That layer starts filtering in its own right after a short time and usually separates finer than the fabric underneath it.

The same part appears in enquiries under several names. A 25 micron centrifuge liner, a basket centrifuge filter bag, a centrifuge basket liner and a filter bag for a centrifuge all mean this component; basket liner is simply the more common word where the bag is understood as lining the basket rather than filtering on its own.

One term needs care in English. A centrifuge bag on its own also returns blood bag centrifugation, which is a different field with its own regulation. Everything on this page refers to industrial solid-liquid separation in a basket centrifuge.

Form, drawstring and how the liner sits in the basket

The bag is cylindrical, is placed into the basket you already have and is positioned by a drawstring at the top edge.

A good fit matters more than it first appears. A bag that is too large throws folds; at a fold the material does not lie evenly, is loaded unevenly and can wear sooner in those places. A bag that is too small sits under tension and can distort as it fills.

What a good fit does not deliver is a guaranteed seal at the rim. Whether liquid runs past the top edge depends on basket geometry, fastening, fill level and the way the machine is run as well.

The four standard sizes

The four sizes cover a range from small baskets to medium industrial ones. Worth noticing: the height does not grow evenly with the diameter. Between size 2 and size 3 only the diameter changes and the height stays at 200 mm. If you are selecting by working height, the next size up is not automatically the right one.

Measure the inside diameter of the basket and the usable depth. If no size fits, we make to measure.

A note on the two centrifuge versions, which often settles the choice on its own: their standard sizes do not overlap. This page covers Ø 200 to 420 mm, the high-throughput version Ø 400 to 480 mm.

Custom centrifuge filter bag: four ways that all work

For basket geometries outside the standard grid there are four routes to a made to measure centrifuge bag, and you only need one of them.

To drawing. The clearest route. A centrifuge filter bag to drawing needs diameter, height, rim detail and fastening, and it can be quoted without follow-up questions.

To dimensions. Where no drawing exists, the inside diameter, the usable depth, the rim form, the base form and the type of fastening are usually enough, together with photographs of the installation.

To a sample. Send us the existing liner, cleaned. We take the dimensions and agree the specification before production.

To a basket you send in. For unusual geometries this is the safest route. The basket comes to us and the custom centrifuge liner is fitted to it.

Centrifuge filter bag replacement: what to keep and what to measure

Centrifuge liners are wear parts. They are changed after a certain number of batches because the material is worked mechanically, blinds off, or gives way at the seams and the rim.

For a centrifuge filter bag replacement the question is therefore less about the grade than about the fit. The single most useful thing you can do is keep the old part: a cleaned used liner is a more reliable basis for a replacement centrifuge basket liner than any measurement taken later on an installed basket.

If the old part is gone, we need the inside diameter, the usable depth, the rim and base form, the fastening and a photograph of the installation. Material, medium, temperature and speed belong with it, because they decide whether the same specification is still the right one.

Technical data

The material line is deliberately left open. The live page names polypropylene, polyester and polyamide without assigning them to the four orderable sizes, and we would rather leave a marked gap than publish a figure we cannot evidence. It is the one point that holds up this page.

25 micron or high throughput

Frequently asked questions about the 25 micron centrifuge filter bag

The questions we get concern the grade, the fit, the material and the difference to the high-throughput version.

Is 25 micron a guaranteed separation limit?

No. The figure describes the grade of the filter material fitted. Actual retention depends as well on particle shape, medium, load, speed and the solids layer that builds up during the run.

Will the liner fit my centrifuge basket?

Four standard sizes cover Ø 200 × 180 to 420 × 250 mm. Measure the inside diameter and the usable depth. For a different geometry we make to measure.

Which material is used?

The standard version is shown in the technical data table. Polyester and polyamide are available as special materials on request, for instance at raised temperature or with abrasive media. The choice follows from medium, temperature and mechanical load.

What is the difference to the high-throughput version?

This version retains finer solids. The high-throughput version is built for quick drainage and for handling components, uses two differently constructed fabrics and has straps instead of a drawstring.

Is the liner released for my centrifuge?

There is no blanket release for every centrifuge. Basket dimensions, rim form, fastening, speed, load and medium all have to suit. For safety-relevant applications the machine manufacturer belongs in the assessment.

How is the liner held in the basket?

By the drawstring at the top edge. Whether that fastening suits your machine depends on the basket rim and the fitting already there. For different fastenings we make to measure.

Can you copy an existing liner?

Yes. Send us the cleaned old part or send in the basket. Either route gives a fitting result without you having to measure anything.