AXEON FST and FSD Series — Single and Multi-Stage Cartridge Filtration

A pressure vessel containing a replaceable filter cartridge inline within a water treatment system. The housing maintains system pressure, directs flow through the cartridge media, and allows cartridge removal and replacement without breaking the pipe connection. The housing is the permanent component; the cartridge is the consumable.

What Is the Difference Between a Single and Multi-Stage Housing?

Sizing rule: always size for peak flow, not average flow. A system averaging 8 GPM that spikes to 20 GPM during filling cycles or CIP events points toward an FSD-200 rather than an FST — the peak exceeds the FST's 15 GPM ceiling, though final selection should also account for media type and allowable pressure drop.

FSD Technical Specifications

Housing Construction

• Housing body and caps: Polypropylene (HFPP)
• O-ring material: Buna-N
• Port connections: 3/4" FNPT or 1" FNPT (specified at order)
• Includes AXEON 0–100 PSI pressure gauges

Operating Parameters

• Minimum / maximum operating pressure: 45 PSI / 85 PSI (75 PSI recommended regulator setting)
• Temperature range: 40°F to 100°F
• Maximum rated flow: 30 GPM

Cartridges are sold separately and are compatible with any standard cartridge in the correct diameter and length for the FSD series — contact LibertyCES for cartridge selection by application.

What Flow Rate Can a 10-Inch Housing Handle?

Both series are available in 10-inch and 20-inch cartridge configurations. Cartridge length primarily affects media volume, pressure drop, and service interval; final flow performance depends on cartridge media type and allowable differential pressure. 10-inch cartridges carry lower media volume, higher pressure drop at equivalent flow, and shorter service intervals — appropriate for lower-volume applications or light sediment load. 20-inch cartridges provide greater media area, generally lower pressure drop at equivalent flow, and extend service life under the same contamination load — preferred when differential pressure rise, not a fixed schedule, is the replacement trigger.

When to Replace Industrial Filter Cartridges — The Differential Pressure Rule →

What Are the Best Housing Options for Industrial Applications?

The right housing depends on three variables: peak flow, operating temperature, and whether the application requires certified materials in the wetted path. For commercial and light-industrial water treatment within standard operating conditions, AXEON FST and FSD systems are well-suited to sediment pre-treatment, carbon block filtration, and multi-stage pre-treatment skids — the FSD series' polypropylene housing with FNPT connections, rated to 100°F and 85 PSI maximum, fits RO pre-treatment trains, point-of-use filtration, and light commercial process water within that service range.

For applications requiring stainless steel construction, elevated temperature service, or sanitary-rated wetted surfaces — food-grade sanitary service, high-temperature process lines — FSD polypropylene housings with FNPT connections are not the right specification. LibertyCES sources and specifies stainless steel housing alternatives separately for those environments.

Food and Beverage Process Water Filtration — NSF and FDA Compliant →

When Should I Specify a Dual or Triple Cartridge Housing?

1. Peak flow exceeds 15 GPM. Above the FST's listed ceiling, differential pressure rises and cartridge service life shortens under load the housing wasn't rated for.
2. A multi-stage sequence is required. Sediment pre-filtration followed by carbon block — a common pre-treatment train ahead of RO — fits in a single FSD-200 or FSD-300 frame rather than separate housings plumbed in series.
3. The design calls for staging from the start. Pressure drop and service life across each stage still depend on cartridge media type and contaminant loading — FSD provides the configuration; final performance depends on how it's specified and loaded.
4. The system is planned around a defined multi-stage layout. Starting with an FST and later needing additional stages typically means adding or replumbing housings rather than converting the original into a staged assembly.

How to Size a Cartridge Filter Housing for Peak Flow →

Related Resources

Frequently Asked Questions