Process filters

Buying guide

Matching a process filter to the stream it runs

What settles a process filter purchase is rarely a single catalogue figure. It is the match between the filter and the stream it has to handle: the volume, the viscosity, the particle or molecule being removed, and whether the duty is clarification, concentration or final sterile filtration. A tangential flow filtration system sized for a 500 litre batch is the wrong tool for a 2 litre laboratory prep, and a 0.2 micron sterilising-grade cartridge does nothing useful where the target is a 50 kilodalton protein. So the first question is the separation itself, membrane cut-off or resin chemistry, flow area, and the pressure the housing is rated to hold. Read these from the part number and the datasheet, not from the listing title, because a housing and the element inside it are often sold and priced separately.

On a used filter, the element and the hardware have different lives. Stainless housings, skids and pumps tolerate age well and can be requalified. Membranes, cassettes and resins degrade, foul and carry a cleaning history that a photograph will not show, so verify whether a unit is offered with fresh consumables or as hardware only. Where an integrity tester is in scope, confirm the model still holds calibration and that the test program matches the membranes you intend to run. Ask what service the unit last had and whether any wetted parts were replaced; a filter integrity tester with an expired calibration is a maintenance item, not a ready instrument.

Price follows that split closely. What a filter costs here ranges from EUR 2 for a bare consumable to EUR 236.745 for an assembled bioprocessing filtration system, with an average near EUR 5.809. A modest budget buys resins, replacement cassettes and smaller benchtop rigs; the upper band covers skid-mounted tangential flow systems from the established makers. The brands that fill the catalogue, Millipore, Acros Organics, Pall, Sartorius, Repligen, set that spread, and refurbished units listed for sale sit below the price of equivalent new hardware. Warranty is arranged in consultation for the specific listing, so where the choice between new and used is close, the individual listing is where that question is answered.

Types of Process filters

Which process filter types are listed?

Among the listings that specify a type, six recur. Tangential flow filtration systems, also called crossflow systems, pass the feed parallel to the membrane so retained material sweeps clear rather than blinding the surface; they concentrate and diafilter proteins, cells and viral particles and are a mainstay of bioprocessing and protein purification. Ion-exchange resins, listed under both the hyphenated and open spellings, are packed beds that bind charged species and release them on elution, the working medium of chromatography-scale separation in molecular biology and biomanufacturing. Bioprocessing equipment covers the housings, holders and skids that carry membranes at production volume. Filter integrity testers are the instruments that confirm a sterilising membrane is intact before and after a run, the gate every aseptic process depends on. Sample preparation resins serve smaller-scale cleanup ahead of analysis.

The work these do reaches across the life sciences. Tangential flow filtration is how a monoclonal antibody is concentrated in biomanufacturing, and a tangential flow filtration system for protein purification is a routine line item in a downstream suite. Ion exchange resin sits at the heart of ion exchange chromatography for protein purification, and the same chemistry clarifies buffers for cell culture and immunoassay work. Integrity testing underpins sterile filtration for bioprocessing, from vaccine fill to media preparation. These filters are also used for clarifying fermentation broth and for endotoxin reduction in biomanufacturing.

The brands behind the process filter listings

The catalogue is led by Millipore, Acros Organics, Pall, Sartorius, Repligen. For a buyer this matters in practical terms: the membrane and cartridge makers among them use defined connection standards and published part numbers, so a cassette or element can be matched to an existing housing and a replacement sourced with confidence. Parts can be sourced via Questpair where a listing covers hardware alone. Their dominance also makes models easy to compare across listings, because the same series recurs under several of the 14 suppliers.

What a used process filter costs here

The condition mix runs 80 percent used. Prices range from EUR 2 to EUR 236.745. That spread covers everything from a single resin charge to a fully plumbed filtration skid, which is why the average near EUR 5.809 says less than the range itself. Catalog listings mark condition per unit, so the gap between a bare consumable and an assembled system is visible on each.