If you’ve ever worked around industrial conveying systems, you’ve probably heard the phrase “metal detector conveyor section” (or “metal-free conveyor section”). It sounds simple, but it solves a very specific problem: metal detectors can be overly sensitive to nearby metal parts of the conveyor, which can cause nuisance trips, inconsistent performance, or reduced sensitivity.
That’s where fiberglass composite (FRP) conveyor sections come in. They’re not a “cool material trend” — they’re a practical way to make inspection equipment behave the way it’s supposed to.
What is a “metal detector conveyor section”?
A metal detector conveyor section is a portion of a conveyor — usually the frame, side rails, guards, and sometimes bed supports — that’s intentionally built from non-metallic, non-magnetic materials so the detector can operate with:
- fewer false positives (“nuisance rejects”)
- more stable calibration
- improved sensitivity (especially when chasing very small contaminants)
In most plants, it’s not that the entire conveyor is a problem. It’s the conveyor components inside or near the detector’s field that can interfere.
Why fiberglass composites are a good fit
Fiberglass reinforced polymer (FRP) is commonly used here because it hits a rare combo of traits:
1) Non-metallic and non-magnetic
That’s the whole point — it reduces the “background noise” the detector has to fight through.
2) Corrosion resistance
Conveyors often live in harsh places: washdown areas, food plants, chemical environments, humid rooms, outdoor exposure. FRP handles corrosion well compared with carbon steel and avoids rust-related maintenance.
3) Strength-to-weight
FRP can be plenty strong while staying relatively lightweight, which helps in installations where you’re swapping sections or adding inspection equipment.
4) Electrical insulation
In certain environments, insulation is a helpful safety and reliability feature (though grounding and ESD considerations still matter depending on the process).
Where these sections show up most often
You’ll most commonly see FRP metal detector conveyor sections in:
- Food processing & packaging (where detection and sanitation are major priorities)
- Bulk material handling where product purity matters
- Plastics, rubber, or composites manufacturing
- Chemical plants where corrosion resistance is a constant concern
- Recycling sorting lines (sometimes paired with other sensing equipment)
What’s typically included in an FRP detector section
This varies by line and detector type, but common components are:
- Conveyor frame / side rails
- Stringers / supports
- Guarding and covers
- Mounting brackets or transition plates (often designed carefully to avoid metal inside the detection zone)
Some setups keep the belt and rollers standard while making the surrounding structure metal-free; others go further depending on sensitivity requirements.
“How do we make sure it actually works with our detector?”
This is the part people sometimes underestimate: metal detectors aren’t all the same, and the detector’s field geometry matters.
A good detector section design starts with:
- detector make/model and aperture size (or tunnel dimensions)
- how the detector is mounted relative to the conveyor
- target sensitivity and product type (wet/salty products behave differently than dry ones)
- where metal must be avoided (the detector’s “keep-out zone”)
That’s why “metal-free” usually means metal-free in the right places, not necessarily zero metal anywhere on the machine.
Maintenance and durability considerations
FRP holds up well, but smart design choices help a lot:
- Wear points: areas that rub (guides, bed supports) may need wear strips or replaceable parts.
- Fasteners: sometimes you can use non-metal fasteners; sometimes you’ll still use metal fasteners but keep them outside the detector zone.
- Cleaning: for washdown, edge sealing and smooth surfaces can reduce grime traps.
- Impact protection: if the line sees pallet hits or forklift traffic, consider guards or sacrificial bumpers.
Practical takeaways
If you’re fighting metal detector nuisance trips or need higher sensitivity, a fiberglass detector section is often one of the cleanest mechanical fixes. It’s not about “upgrading materials” — it’s about making the inspection equipment’s environment predictable.
We at Custom Fiberglass Products Inc. build fiberglass metal detector conveyor sections—frames, rails, guarding, and the odd custom transition pieces that make the install behave the way it should. Typically, it’s not about replacing an entire conveyor; it’s about creating a stable, low-interference zone around the detector so sensitivity and uptime are easier to maintain.