Overview of Tube Magnets

Tube Magnets—industry-standard components often referred to as magnetic rods or bars—serve as the foundational elements of modern magnetic separation systems.

While externally simple, these units encapsulate a precision-engineered magnetic circuit within a seamless, fully sealed SS304 or SS316L housing. We customize this internal core to match specific operational demands: utilizing Neodymium (NdFeB) for maximum field intensity, Samarium Cobalt (SmCo) for extreme thermal resilience, or ferrite for economical durability.

This optimized array projects a powerful magnetic field through the stainless steel casing, creating a continuous force designed to securely capture ferrous contaminants from the product stream. Deployable as standalone units or integrated into grate magnets, drawer magnets, or magnetic liquid traps, they efficiently extract iron from free-flowing powders and liquids—ensuring product purity and protecting equipment.

Tube Magnets

Internal Construction & Operating Principle of Tube Magnets

To ensure long-term performance in demanding environments, our tube magnets are built within a fully welded and hermetically sealed SS304 or SS316 housing. This protective shell encloses a high-density magnetic circuit, which is meticulously assembled from a stack of permanent magnets and conductive steel pole pieces. For flexible installation, we offer multiple end configurations, allowing you to choose between tapped holes, threaded studs, or handles based on your facility’s specific mounting needs.

In the magnetic separation industry, surface gauss is commonly utilized as the primary metric for quality acceptance. Users often rely on Gauss meters to verify specified ratings—ranging from standard 6,000 Gs units to ultra-high intensity 15,000 Gs models—as a standard part of their procurement process.

Internal Construction of Tube Magnets-New
Magnetic Circuit-Tube Magnets

However, while achieving a high surface gauss is a necessary starting point, it is not the only factor that determines performance. For the successful capture of weakly magnetic particles or fine dust in fast-moving streams, the magnetic gradient is the decisive factor. This gradient creates a “snap effect” that pulls contaminants toward the tube surface, preventing them from being swept away by the product flow.

To achieve the ideal balance of high surface gauss and intense gradient, the tube magnets utilize a repelling pole configuration (N-N, S-S). By forcing identical poles against each other, this design triggers magnetic compression, which prevents magnetic flux lines from remaining within the magnet mass. Instead, the flux is driven outward and concentrated into the conductive steel pole pieces. This creates high-intensity pole peaks across the tube surface, maximizing the capture efficiency for even the most challenging ferrous contaminants.

Tube Magnets Performance Fe vs. Non-Fe Separation

Housing Material & Geometric Profiles

Stainless Steel Housing Options

The integrity of the magnetic circuit is protected by a precision-finished stainless steel “skin,” available in two primary grades:

  • SS304 (Industrial Standard): Engineered for non-corrosive environments such as plastics and recycling. It provides high durability and abrasion resistance for general industrial use.

  • SS316L (Sanitary Grade): The prerequisite for high-hygiene sectors, including dairy and pharmaceuticals. This grade offers superior resilience against chlorides and acidic cleaning agents.

  • Surface Finish: For sanitary applications, tubes are polished to Ra ≤ 0.4μm. This mirror-like finish eliminates microscopic crevices, ensuring compliance with global food safety standards.

Geometric Engineering for Flow Dynamics

While the round rod is the industry standard, specialized profiles are available to solve specific flow challenges:

  • Square Profile: Utilized for specialized rectangular chutes or installations requiring secure, non-rotating mounting.

  • Teardrop Profile (Anti-Bridging Design):

    • Flow Optimization: Designed for cohesive powders (e.g., flour, starch) prone to “bridging.” The tapered leading edge slices through the material stream to prevent accumulation.

    • Enhanced Capture: The streamlined profile creates a controlled turbulence zone, redirecting particles back into the high-intensity magnetic field without restricting flow.

Fabrication & Inspection Standards

To ensure long-term durability and contamination control, tube magnets follow a standardized fabrication sequence. This process ensures that every component, from the internal magnetic circuit to the external housing, meets rigorous industrial performance requirements.

Magnetic Core Assembly

The process begins with rigorous material preparation and precision alignment of the internal magnetic circuit to ensure strict adherence to the specified magnet pitch. Pre-encapsulation verification is performed to confirm the alignment of the magnets and conductive steel pole pieces before the final assembly stage.

Hermetic Sealing & Surface Finishing

In place of adhesive-based assembly, end caps are fully welded to the housing to create a hermetic seal. Following the welding process, the stainless steel surface is finished to suit the specific application environment. A standard industrial smooth finish is provided for general material handling to ensure ease of cleaning and material flow. For specialized high-hygiene sectors, an optional precision polish reaching Ra ≤ 0.4μm is available to meet stringent sanitary standards.

Structural Integrity & Leak Verification

Once the surface finishing is complete, the structural integrity is verified through rigorous waterproof and airtightness testing. To guarantee the tube magnets remain physically impenetrable to liquids, units undergo hot water immersion (bubble tests) or hydrostatic pressure testing upon request. Performing these tests after polishing ensures that any potential micro-defects at the weld points are identified before the product is cleared for operation.

Magnetic Performance Verification

A final flux density scan is conducted across the entire length of every unit to guarantee performance consistency. This inspection confirms that the surface gauss meets the exact specifications required for effective particle capture and high-intensity extraction during heavy-duty operations.

Ready to Optimize Your Separation Process?

Because every material stream is unique, we engineer diameters and magnetic circuits specifically for your material flow rates to ensure maximum capture efficiency. Consult with our engineers.