If you're looking at filtration separation for your shop, the first question isn't which name to look for-it's whether you need to filter particles out of a liquid stream or keep machine coolant free of floating oil. These two products answer that question from opposite ends of the workflow.
Quick verdict
Pick the Duda Energy Industrial Filter Sock Bags if you already have a filter bag housing and need a fresh supply of fine bags for water, oil, WVO, or fuel. Pick the PreAsion Oil Water Separator if your machine tools use cutting fluid and you want floating oil skimmed away continuously.
At a glance
| Duda Energy Filter Sock Bags | PreAsion Oil Water Separator | |
|---|---|---|
| Price | USD 327.83 for a lot of 50 | USD 1,703.84 |
| Format | Size #4 4" x 14" bags with plastic ring flange | 208-240V 3PH cutting fluid skimmer |
| Filtration job | Fine particle removal from liquids | Floating oil separation from cutting fluid |
| Power needed | None | 3-phase 208-240V supply |
| Best for | Filter bag housing users | Machine tool coolant maintenance |
Where each product wins
Where Duda Energy wins
The case for the Duda Energy bags is recurring filtration. Instead of a single machine, you're stocking up on a disposable filter that drops into an existing housing. That fits shops that know exactly what they're filtering and want to standardize on one bag size.
Where PreAsion wins
The case for the PreAsion separator is automation. It runs continuously to pull floating oil off the cutting fluid surface, which a passive filter bag can't do. That makes it the better system-level answer for machine tool coolant maintenance.
Product notes
Duda Energy Welded Industrial Filter Sock Bags
This lot of 50 welded filter bags is a straightforward consumable for liquid filtration. Each bag is Size #4, 4" x 14", with a plastic ring flange, and the 0.5-micron rating puts it on the fine side of filtration. The welded construction eliminates needle holes and thread contamination, which is a real benefit when you're filtering fluids that need to stay clean. At $327.83 for 50 bags, the per-bag price is about $6.56. The limitation is that these bags are media, not a standalone machine: they need a compatible 4-inch flange filter bag housing to do their job. If that housing is already in place, this lot gives you a practical supply of replacement bags for water, liquid oil, WVO, or fuel.
PreAsion Oil Water Separator
This is a powered oil water separator built for machine tool cutting fluid. It uses a skimmer to pull floating oil off the coolant surface, with oil drainage that lets you recover and reuse the separated oil. The intended effect is a longer cutting fluid life, more consistent machining accuracy, and a cleaner working environment. It runs on 208-240V three-phase power, so it belongs in a shop with that electrical supply already available. The price is $1,703.84, which makes it the far larger investment compared with the filter sock lot. The limitation is that it's not a universal add-on: you need a three-phase 208-240V machine tool setup, and the unit is focused on cutting fluid oil separation rather than general particle filtration. For a shop running machine tools, this is the equipment-level solution.
Final choice by use case
For particle removal through an existing housing, the Duda Energy filter sock bags are the practical purchase. For oil removal in a cutting fluid system, the PreAsion oil water separator is the equipment that addresses the cause.
