AXEON FST and FSD Series — Single and Multi-Stage Cartridge Filtration Systems for Commercial Flow Rates
Housing selection is a flow decision, not a catalog decision. The AXEON FST handles up to 15 GPM in a single-housing configuration. The FSD scales to 30 GPM across single-, dual-, and triple-stage configurations. Getting that call wrong at specification sets up cartridge bypass, premature loading, and shortened service life under peak demand.
What Is a Cartridge Filter Housing?
A cartridge filter housing is the pressure vessel that holds a replaceable filter cartridge in-line on a water treatment system. The housing maintains system pressure, channels 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. Sizing the housing correctly for flow rate and operating conditions determines whether the cartridge performs to its rated specification — or bypasses, loads prematurely, or fails to meet its reduction claim at peak demand.
AXEON FST and FSD are commercial-grade cartridge filtration systems designed for water treatment applications from sediment pre-treatment to carbon block polishing and RO pre-filtration.
What Is the Difference Between a Single and Dual Cartridge Housing?
The FST and FSD represent different filtration system configurations — and the distinction is fundamentally a flow rate and staging decision.
AXEON FST — Single Cartridge Housing
AXEON lists the FST as a single cartridge filter housing available in 10-inch and 20-inch sizes, with flow rates up to 15 GPM. Single-housing configurations are appropriate when:
- System peak flow stays at or below 15 GPM
- Pre-treatment position is ahead of a single RO unit or smaller skid
- Filtration sequence requires only one media stage
AXEON FSD — Multi-Stage Cartridge Filtration System
The FSD series is designed for higher flow and multi-stage filtration sequences. Available configurations:
- FSD-100 Series: Single-stage (FSD-110 for 10" cartridges, FSD-120 for 20")
- FSD-200 Series: Dual-stage (FSD-210, FSD-220)
- FSD-300 Series: Triple-stage (FSD-310, FSD-320)
Maximum rated flow for the FSD is 30 GPM. Specify FSD when system peak flow exceeds the FST ceiling, when the initial design calls for multiple filtration stages in sequence, or when the system is planned around a defined multi-stage configuration.
The sizing rule: always size for peak flow, not average flow. A system running at 8 GPM average 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 listed 15 GPM ceiling, though final selection should account for media type and allowable pressure drop.
See also: How to Size a Cartridge Filter Housing for Peak FlowWhat Flow Rate Can a 10-Inch Cartridge Housing Handle?
Both FST and FSD series are available in 10-inch and 20-inch cartridge length configurations. AXEON lists the FST and FSD flow ceilings by series; cartridge length primarily affects media volume, pressure drop, and service interval. Final flow performance depends on cartridge media type and the allowable differential pressure for the application.
10-Inch Cartridges
- Lower total media volume for a given media type
- Higher pressure drop at equivalent flow relative to a longer cartridge of the same media
- Shorter service interval at equivalent flow and contaminant loading
- Appropriate for lower-volume applications or positions where sediment load is light
20-Inch Cartridges
- Greater media area in the same housing diameter
- Generally lower pressure drop at equivalent flow relative to the 10-inch version of the same cartridge type
- A 20-inch cartridge generally provides more media and surface area than a 10-inch cartridge of the same type, which can extend service life under the same contaminant load
- Preferred when differential pressure rise — not a timed schedule — is the replacement trigger
Confirm Your Housing Configuration Before the Purchase Order
Use the Industrial Cartridge Filtration Spec Check to verify housing model, stage count, and cartridge selection against your system's peak flow requirements.
Download the Free Spec CheckAXEON FSD Series — Technical Specifications
Model Configurations
| Series | Configuration | 10" Model | 20" Model |
|---|---|---|---|
| FSD-100 | Single-stage | FSD-110 | FSD-120 |
| FSD-200 | Dual-stage | FSD-210 | FSD-220 |
| FSD-300 | Triple-stage | FSD-310 | FSD-320 |
Housing Construction
| Specification | FSD Series Detail |
|---|---|
| Housing body | Polypropylene |
| Cap construction | Polypropylene (HFPP) |
| O-ring material | Buna-N |
| Port connections | 3/4" FNPT or 1" FNPT (specified at order) |
| Included | AXEON 0-100 PSI pressure gauges |
Operating Parameters
| Parameter | FSD Series Rating |
|---|---|
| Minimum operating pressure | 45 PSI |
| Maximum operating pressure | 85 PSI |
| Recommended regulator setting | 75 PSI |
| Minimum temperature | 40°F |
| Maximum temperature | 100°F |
| Maximum rated flow | 30 GPM |
Dimensions (W × D × H)
| Series | 10" Cartridge | 20" Cartridge |
|---|---|---|
| FSD-100 (single-stage) | 8 × 7.5 × 17.5" | 8 × 7.5 × 27.5" |
| FSD-200 (dual-stage) | 8 × 15 × 17.5" | 8 × 15 × 27.5" |
| FSD-300 (triple-stage) | 8 × 22.5 × 17.5" | 8 × 22.5 × 27.5" |
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.
AXEON FST Series — Technical Specifications
| Specification | FST Series Detail |
|---|---|
| Configuration | Single cartridge housing |
| Available sizes | 10-inch cartridge length; 20-inch cartridge length |
| Maximum rated flow | 15 GPM |
| Full data sheet | Contact LibertyCES directly for complete FST dimensional specifications, materials, and cartridge compatibility data. |
For complete FST dimensional specifications, materials, and cartridge compatibility data, contact LibertyCES directly. We source through AXEON and can pull the full data sheet for your application before you specify or purchase.
James Riggins — james@libertyces.com | sales@libertyces.com | (559) 395-5500 | libertyces.com
What Are the Best Filter 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 used in sediment pre-treatment, carbon block filtration, and multi-stage pre-treatment skids. The FSD series — polypropylene housing with FNPT connections, rated to 100°F maximum and 85 PSI maximum — is well-suited for RO pre-treatment trains, point-of-use filtration, and light commercial process water applications that fall within the polypropylene service range.
For applications requiring stainless steel construction, elevated temperature service, or sanitary-rated wetted surfaces:
FSD polypropylene housings with FNPT connections are not the right specification for those environments. For food-grade sanitary service, high-temperature process lines, or applications requiring stainless steel wetted surfaces — LibertyCES sources and specifies stainless steel housing alternatives separately.
When Should I Specify a Dual Cartridge Housing?
Specify an FSD multi-stage configuration over an FST single-housing when any of the following apply:
- Peak flow exceeds 15 GPM. The FST is listed at a 15 GPM maximum. At higher peak demand, the system operates above the FST's ceiling — differential pressure rises, cartridge service life shortens, and filtration performance at rated specification cannot be assumed.
- Multi-stage filtration sequence is required. If the application calls for sediment pre-filtration followed by carbon block — a common pre-treatment train ahead of RO — an FSD-200 or FSD-300 handles both stages in a single frame rather than separate housings in series.
- The design calls for a multi-stage configuration from the start. FSD configurations give a higher listed system flow ceiling than FST and support multi-stage treatment sequences. Pressure drop and service life across each stage still depend on cartridge media type, contaminant loading, and how stages are arranged — the FSD series provides the configuration; final system performance depends on how it's specified and loaded.
- The system is being designed for a defined multi-stage layout. Starting with an FST and later needing additional stages may require adding or replumbing additional housings rather than simply converting the original FST into a staged assembly.
Related Technical Resources
-
Industrial Cartridge Filtration Systems
Full specification authority page: housing selection, cartridge types, flow sizing, and system design.
https://libertyces.com/industrial-cartridge-filtration-systems -
Food and Beverage Process Water Filtration
NSF/ANSI 61 and FDA 21 CFR requirements when cartridge filtration is in the food-grade process water path.
https://libertyces.com/food-beverage-process-water-filtration-nsf-fda -
Carbon Block Cartridges — NSF Chlorine Removal and RO Protection
Matching carbon block flow rating to system peak flow.
https://libertyces.com/carbon-block-cartridges-chlorine-removal-ro-protection -
How to Size a Cartridge Filter Housing for Peak Flow
Step-by-step housing sizing for variable-flow systems.
https://libertyces.com/how-to-size-cartridge-filter-housing-peak-flow -
When to Replace Industrial Filter Cartridges — The Differential Pressure Rule
DP-based replacement decisions for commercial and industrial cartridge systems.
https://libertyces.com/when-to-replace-industrial-filter-cartridges-differential-pressure -
RO Pre-Treatment Filtration — Specifying 5-Micron Protection
Pre-treatment filtration requirements ahead of reverse osmosis membrane arrays.
https://libertyces.com/ro-pre-treatment-filtration-5-micron-protection
Specify or Source AXEON Cartridge Filter Housings Through LibertyCES
Questions on housing model selection, FSD stage count, cartridge compatibility, or FST data sheet requests for your application — we source directly through AXEON and can get you to the right spec before the purchase order.
James Riggins — james@libertyces.com
Phone: (559) 395-5500
Sales: sales@libertyces.com
Website: libertyces.com
LinkedIn: LibertyCES