Free-fall Metal Detector | Gravity Metal Separator for Powders & Granules
Eliminate Fe & SUS contamination from free-flowing powders and granules. Our vertical free-fall metal detector uses a 304 SS detection tube, millisecond flap-valve rejection, and capacities up to 10 t/h — ideal for plastics, food ingredients, chemicals and pharma raw materials.
Free-fall Metal Detector | Gravity Metal Separator for Powders & Granules
Unlike belt-fed systems that carry packaged or formed goods, the Free-fall Metal Detector is purpose-built for loose, dry, free-flowing materials — powders, flakes, pellets and granules that move under gravity rather than on a conveyor. Material drops vertically from a hopper, silo or dosing pipe, accelerates through a precision-machined detection tube, and is scanned in mid-air by a high-frequency electromagnetic coil. The moment a ferrous or stainless particle is identified, an ultra-fast diverter flap ejects the contaminated fraction within milliseconds, while clean product continues its downward path uninterrupted.
Available in three tube diameters (75 / 100 / 150 mm) and throughputs from 3 to 10 tons per hour, the unit mounts directly into existing vertical pipelines — no extra floor space, no horizontal transfer, no product deformation. It is the preferred contamination-control choice wherever bulk ingredients are metered, blended or bagged: plastic compounding, food ingredient dosing, chemical powder handling and pharmaceutical raw-material intake.
Application Industries
The free-fall configuration excels wherever material is conveyed by gravity in a dry, dispersed state:
Plastics & Polymer Compounding
Inspects virgin and regrind pellets, masterbatch, and engineering resins before they reach the extruder or injection barrel, protecting screws and molds from costly metal-induced damage.
Food Ingredient Dosing
Screens flour, starch, sugar, milk powder, spice blends, cocoa and additive premixes as they fall into mixers or filling heads, safeguarding HACCP-controlled lines.
Chemical & Pigment Powders
Monitors titanium dioxide, fillers, catalysts and colorant granules where even a tiny ferrous speck can ruin a batch or catalyze an unwanted reaction.
Pharmaceutical Raw Materials
Verifies API powders, excipients and granulated intermediates prior to tableting or encapsulation, supporting GMP traceability.
Animal Feed & Grain Processing
Removes tramp metal from milled grain, protein meals and pellet premixes in high-volume vertical chutes.
Industry Pain Points & Professional Solutions
Bulk powder and granule lines face a distinct set of failure modes that belt detectors simply cannot address. Each is met here with a dedicated engineering response.
Challenge — Product bridging and tube blockage. Fine or slightly humid powders tend to arch inside narrow passages, halting flow. Response:The detection tube features a polished, large-radius internal profile and an optional vibratory collar that keeps material in a steady free-fall curtain, preventing hang-up without compacting the stream.
Challenge — The “product effect” of moist or conductive powders. Damp ingredients generate a false signal that mimics metal. Response:Multi-frequency phase analysis separates the conductive moisture signature from genuine metal response, auto-tuning the baseline for each recipe and cutting nuisance trips dramatically.
Challenge — Limited vertical headroom in retrofits. Plants rarely have space to add a horizontal inspection station. Response:The compact in-line frame slips between an existing hopper outlet and the downstream pipe, adding only a short vertical segment — no layout redesign required.
Challenge — Slow rejection losing good product. A sluggish diverter discards kilograms of clean material with every fault. Response:A pneumatically actuated flap valve (0.5 MPa) flips in milliseconds, isolating only the contaminated pocket and returning instantly to the open position, minimizing giveaway.
Challenge — Dust ingress into electronics. Airborne fines destroy conventional control cabinets. Response:The control head is fully sealed and physically separated from the product zone, with gasketed cable glands rated for dusty environments, ensuring long-term reliability in milling and blending rooms.
Core Product Features & Technical Advantages
True Gravity-Flow Architecture
No belt, no rollers, no product contact surfaces to wear or clean. Material moves purely by gravity, eliminating mechanical contamination sources and slashing sanitation time between batches.
High-Speed Flap-Valve Rejection
The integrated diverter reacts in a fraction of a second, ejecting metal-bearing material into a locked collection port while preserving the integrity and quantity of accepted product.
Calibrated Sensitivity per Tube Size
Detection thresholds are matched to aperture: Fe from 0.5 mm and SUS from 1.0 mm on the 75 mm tube, scaling to Fe 0.7 mm / SUS 2.0 mm on the 150 mm tube — verified at idle and maintained under load through continuous auto-balance.
Throughput Matched to Your Line
Three capacity tiers (3 / 5 / 10 t/h) let you right-size the detector to your dosing rate, avoiding both bottlenecking and overspending on unused headroom.
Hygienic 304 Stainless Construction
The entire product-wetted frame and tube are fabricated from food-grade 304 stainless steel with smooth, crevice-free welds — compatible with dry cleaning and washdown protocols.
Plug-in Pipeline Integration
Standard flange and clamp connections let the unit bolt straight into vertical ducting, with the control panel positioned for easy operator access and the reject bin placed for safe, tool-free emptying.
Technical Specifications
Parameter
TYA-MDP75
TYA-MDP100
TYA-MDP150
Detecting Tube Size
75 mm
100 mm
150 mm
Detecting Sensitivity
0.5 mm (Fe) / 1.0 mm (SUS)
0.6 mm (Fe) / 1.2 mm (SUS)
0.7 mm (Fe) / 2.0 mm (SUS)
Detecting Capacity
3 ton/h
5 ton/h
10 ton/h
Material of Machine Frame
Stainless steel 304
Stainless steel 304
Stainless steel 304
Power Supply
AC 220V 50Hz
AC 220V 50Hz
AC 220V 50Hz
Air Pressure
0.5 MPa
0.5 MPa
0.5 MPa
FAQ
Q: Will slightly damp or sticky powders clog the detection tube?
The tube’s polished, large-radius bore resists build-up, and an optional vibratory collar keeps the stream in free fall. For highly hygroscopic materials we recommend pairing the unit with upstream dehumidified conveying.
Q: How fast is the reject flap, and how much good product is lost per fault?
The pneumatic flap actuates in milliseconds at 0.5 MPa, isolating only the contaminated pocket. In practice, giveaway per event is measured in grams, not kilograms.
Q: Can the detector be installed into my existing silo discharge pipe?
Yes. Standard flange/clamp interfaces allow drop-in mounting between a hopper outlet and the downstream line, adding minimal vertical height and requiring no horizontal conveyor.
Q: Does airborne dust affect the electronics?
No. The control head is sealed and mounted away from the product zone, with gasketed cable entries designed for dusty milling and blending environments.
Q: Which model should I choose for plastic regrind pellets?
Selection depends on pellet size and hourly rate: the 75 mm tube suits fine granules at lower rates, while the 100–150 mm tubes handle coarser regrind at 5–10 t/h. Share your pellet diameter and throughput and we will size it precisely.
Contact Us
Engineering a gravity-fed inspection point into your powder or granule line?
Our application team will size the correct tube, sensitivity and reject mechanism for your material.
Product Description
Submit Your Requirements
Please submit your requirement form, and we will customize the most suitable solution according to your needs.
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