PML
Magnetic Rota Grid Separator
Magnetic Rota Grid Separator
Starting from Rs.78,618
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Product Details
At a Glance
A magnetic rota grid separator is a magnetic grill with rotating rods that continuously reorient through the material stream, preventing the bridging and blockages that sticky or moist powders cause in a fixed grill. PML's rota grid separators are rated up to 11,000 Gauss for continuous operation up to 80°C.
Sticky, moist powders don't behave in a fixed grill — they form lumps that bridge across the rod grid and block the flow entirely. The PML Magnetic Rota Grid Separator solves this the way its name suggests: the magnetic rod assembly rotates continuously, so material never gets the chance to lump or bridge, even when it's damp or naturally sticky. It's built for exactly the materials that defeat a static grill — widely used in food, chemical and pharmaceutical processing.
How It Works
The magnetic assembly is a Rota Grid — magnetic rods arranged around the periphery of a shaft, coaxially mounted and driven by a gear motor outside the housing. As the shaft rotates, the grid continuously reorients through the material stream, capturing ferrous contamination while preventing the powder from settling and bridging across it. All powders and granular materials, sticky or free-flowing, can be processed effectively through the same unit.
Standard Range — High-Intensity, 11,000 ± 500 Gauss, Max. Operating Temp. 80°C
| Model No. | Inlet/Outlet Dia. (mm) | Total Height (mm) | Drive (kW) | Magnetic Elements |
| MRGS-1 | 150 | 400 | 0.37 | 5 |
| MRGS-2 | 200 | 450 | 0.37 | 6 |
| MRGS-3 | 250 | 500 | 0.37 | 7 |
| MRGS-4 | 300 | 550 | 0.37 | 9 |
| MRGS-5 | 350 | 600 | 0.37 | 10 |
| MRGS-6 | 400 | 650 | 0.37 | 13 |
Key Advantages
- No Bridging
The rotating grid keeps sticky or moist powders moving instead of forming lumps that block flow.
- Handles What Fixed Grids Can't
Effective on both sticky, moisture-laden material and standard free-flowing powders and granules, in the same unit.
- High-Intensity Capture
11,000 ± 500 Gauss removes fine ferrous contamination reliably.
- Sealed, Geared Drive
The gear drive sits outside the housing, keeping the product-contact area clean and simple to maintain.
Where It's Used
Food, chemical and pharmaceutical processing lines handling sticky, moist or lump-prone powders and granules — anywhere a standard fixed magnetic grid risks bridging and blocking flow. See a real case study on our removing iron from food powders & ingredients page, or how this fits pharmaceutical processing on our pharmaceutical processing page.
Frequently Asked Questions
How is this different from a standard magnetic grill?
A standard grill uses a fixed rod bed, which can bridge and block when material is sticky or moist. The Rota Grid's rods rotate continuously, so lumping material can't build up and block the flow.
What drives the rotation?
A gear motor mounted outside the housing, directly coupled to the rota grid shaft — standard units run on a 0.37kW drive.
Can it handle both sticky and free-flowing material?
Yes — the rotating design handles both without needing different equipment for each.
What size range is available?
Six standard sizes, 150mm to 400mm inlet/outlet diameter, with 5 to 13 magnetic elements depending on size.
What Gauss rating does it use?
11,000 ± 500 Gauss, with a maximum operating temperature of 80°C.
Case Study: Where PML Magnetic Rota Grids Are Already at Work
Vidhi Specialty Food Ingredients Limited
- Problem
- Vidhi was facing repeated rejections from international buyers. An inspection found the cause: a static magnetic grill being used on a sticky food colouring powder. The powder built up on the rods, forming a layer that let contamination pass through without ever touching the magnet.
- Solution
- PML recommended replacing the static grill with a Magnetic Rota Grid Separator, whose rods rotate continuously so sticky powder can't build up and block the field.
- Result
- Vidhi's overseas customers approved samples and passed quality checks immediately, protecting the export business. The results were strong enough that Vidhi is now rolling the Rota Grid out across the entire plant.
Why Buy From PML
- 65+ years of magnetic separation engineering — purpose-built solutions for the materials that defeat standard grills.
- Made and tested in-house — every unit is manufactured and checked to its stated Gauss rating.
- Engineered for difficult materials — sticky, moist and lump-prone powders processed reliably.
- Magnetic calibration and audit services available to verify field strength over time.
Handling a material that keeps bridging your current separator? Enquire now and our engineering team will size the right Rota Grid for your process.
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.
