Product Details
At a Glance
A magnetic rod is the working element inside PML's grills and filters, also sold individually for building or retrofitting a magnetic separation system. PML's rods are hard ferrite ceramic or high-intensity rare-earth magnets encased in seamless Stainless Steel 304 or 316 tube, running 100mm to 600mm in length at 25mm diameter.
The magnetic rod is the working element inside almost every PML grill and filter — and it's also sold on its own, for anyone building or retrofitting a magnetic separation system. Each rod is a hard ferrite ceramic or high-intensity rare-earth magnet, fitted inside a seamless drawn, heat-treated SS 304L tube, sized and finished to extract maximum holding strength from the magnet inside.
Choosing the Right Intensity
| Grade | Field Strength | Best For | Model Series |
| Low-Intensity | 2,500 ± 500 Gauss | Nuts, bolts, screws, broken washers — larger pieces from a distance | LMR 10–LMR 60 |
| Medium-Intensity | 6,000 ± 500 Gauss | Granule-size contamination, 1–4mm | MMR 10–MMR 60 |
| High-Intensity | 11,000 ± 500 Gauss | Fine ferrous particles down to 1 micron | HMR 10–HMR 60 |
All three grades run 100mm to 600mm in length, 25mm diameter, in SS 304 or SS 316 — the same rods that build up our grills and filters can be ordered individually for a custom rig or as replacements for an existing installation.
Key Advantages
- Precision-Built Tubes
Seamless drawn, heat-treated SS 304L tube, wall thickness optimised for maximum field strength at the surface.
- Three Intensity Grades
2,500 to 11,000 Gauss, matched to your contamination size.
- Standard Lengths
100mm to 600mm in 50mm steps — drop-in replacements for existing grills, or building blocks for a custom rig.
- Food and Pharma Ready
SS 304/316 construction throughout, suitable for hygienic processing environments.
Where It's Used
Plastics, food processing (wheat, sugar, coffee, tea, grains, pulses, flour, spices, milk), pharmaceutical, chemical, ceramic, colours and paints, pigments, ink and refractory industries.
Frequently Asked Questions
Can I order rods to fit my existing grill?
Yes — tell us the length and diameter of your current rods and we'll match or upgrade the intensity grade.
What's the difference between the three grades?
It's the size of contamination each one is designed to catch — low-intensity for larger tramp metal, medium for granule-size particles, high-intensity for fine fines down to 1 micron.
SS 304 or SS 316 — which should I choose?
SS 316 offers better corrosion resistance for aggressive or wet environments; SS 304 is standard for general dry-material use.
What lengths are available?
100mm to 600mm in 50mm steps, at 25mm diameter, across all three intensity grades.
Can rods be bought individually, or only as part of a grill or filter?
Individually — the same rods used inside our own grills and filters can be ordered on their own for a custom rig or as replacements for an existing installation.
Why Buy From PML
- 65+ years of magnetic separation engineering — the same rods used inside our own grill and filter product lines.
- Made and tested in-house — every rod is manufactured and checked to its stated Gauss rating.
- Precision tube construction — seamless drawn SS 304L, optimised for magnetic efficiency.
- Magnetic calibration and audit services available to verify field strength over time.
Need a custom length, diameter or intensity? Enquire now and our engineering team will match the right rod to your system.
Why Magnetic Strength Drops in Ferrous Separators (and When to Replace)
Separation efficiency falls as magnetic strength decreases. Below are the most common causes of reduced field strength in NdFeB (neodymium) magnetic separation equipment, along with the warning signs that indicate a magnet or separator needs replacing.
Causes of Reduced Magnetic Strength
- Thermal demagnetization: Standard Neodymium-Iron-Boron (NdFeB) grades lose magnetic strength when exposed to temperatures above their rating — often starting at 80°C / 176°F for standard grades. Exceeding these limits causes a permanent loss of magnetic flux.
- Corrosion and core oxidation: NdFeB is highly iron-rich and oxidizes quickly. If moisture, washdown liquids, or corrosive chemicals breach the outer stainless steel cladding, the magnet swells, crumbles, and loses field strength.
- Mechanical damage and internal cracking: NdFeB is brittle. Dropping magnetic tubes during cleaning, or subjecting them to heavy equipment vibration, causes internal micro-fractures that break the continuous magnetic circuit.
- Strong opposing magnetic fields: A sufficiently strong opposing field can overcome a material's coercivity and flip or randomize its magnetic domain polarity. High alternating current (AC) electric fields, in particular, create powerful local alternating magnetic fields that rapidly scramble domain alignment.
- Material buildup ("air gap" effect): Accumulated fine iron on the surface acts as a barrier, pushing the active magnetic field further away from incoming material. Because magnetic force decays exponentially with distance, even a few millimetres of buildup severely reduces capture rates.
- Increased process velocity or burden depth: Running material too fast, or in overly thick layers, prevents fine ferrous particles from spending enough time in the peak magnetic field zone to be pulled out of the flow.
Signs an NdFeB Magnet or Separator Needs Replacing
- Drop in gauss rating: Annual or semi-annual gauss testing shows a permanent drop of 10–15% or more from the baseline specification.
- Bulging or "pillow" swelling: The protective stainless steel tube cladding looks warped, swollen, or cracked — a sign of internal oxidation where rust has expanded inside the shell.
- Dead spots along the field: Measuring with a gauss meter reveals localised spots with zero or drastically lower magnetic pull across the grid or tube surface.
- Downstream metal contamination: Ferrous fines or tramp iron start showing up in final product testing or downstream machinery detectors despite the separator being clean.
- Structural casing punctures: Scratches, gouges, or pinhole leaks in the stainless steel jacket expose the internal magnetic circuit to moisture and process fluids.
Regular gauss testing (at least annually) is the most reliable way to catch strength loss before it affects downstream product purity — PML's own range of Gaussmeters and magnetic field meters covers this. If you're seeing any of the signs above, talk to our team about testing or replacing your separator.
