Top Mounted Agitators
Top Mounted Agitators
Top Mounted Agitators (TMAi/TMAe)
Solving the Geometric Puzzle
When Bottom-Entry is Not an Option
The Exception to the Rule. At Liquitec, we believe the bottom-mounted magnetic agitator is the gold standard for sterile mixing. It is the most hygienic, stable, and ergonomic solution for 90% of pharmaceutical applications. However, process reality does not always follow the rules.
Engineered for Constraints. When your tank geometry, complex piping layout, or specific process chemistry makes a bottom entry impossible, we deploy our Top-Mounted Series. We do not position this as a competitor to our standard BMA line, but as a specialized, high-performance tool for specific engineering challenges. Whether you are retrofitting a legacy vessel or designing a skid with zero ground clearance, the Top-Mounted series brings hermetic magnetic safety to the top flange.
Advantages
Engineered for the Exception
In processes requiring absolute drainage or complex bottom piping, a bottom-mounted mixer can be a physical obstacle.
- The Constraint: Bottom magnets and their weld-in flanges occupy valuable space on the tank floor and can interfere with drain valves or sumps in small vessels.
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The Solution: The TMA moves the drive train to the roof. This leaves the tank bottom completely free, allowing for optimized, center-drain geometries and simplifying the layout of harvest piping.
In crystallization or suspension processes, heavy solids settle and pack at the tank bottom.
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The Risk: Starting a bottom-mounted mixer while the bearing is buried in abrasive "sludge" can lead to rapid ceramic wear or failure.
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The Solution: With a Top-Mounted drive, the bearings are located safely in the headspace, far from the sediment zone. The impeller hangs down and, upon startup, lifts the solids away from the floor without the bearing ever grinding against the particulates.
The industry is filled with legacy vessels operating with leaking mechanical seals on top flanges.
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The Challenge: Cutting a hole in the bottom of a certified pressure vessel to install a bottom mixer is often a regulatory and financial impossibility.
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The Fix: We engineer magnetic drive units that fit your existing DIN or ANSI top flange patterns. This allows you to upgrade from a mechanical seal to a hermetic magnetic drive using the existing vessel interface—preserving your tank's pressure certification.
Top-mounting a magnetic shaft without a bottom support introduces specific physics: deflection and thermal expansion.
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The Liquitec Standard: We calculate the critical speed and shaft diameter for every unit. We are transparent about the limits: without a Lower Bearing Support (LBS), the shaft length is physically limited by the critical speed. We engineer within these safe limits to ensure the shaft remains stable without whipping.
Options
Adapting to Your Geometry.
Power Density (Torque Range)
We size the magnetic coupling to the viscosity and volume of your specific process, ensuring you never pay for unneeded weight on your top flange.
- The Range: From micro-scale 30 Ncm drives for pilot reactors up to 2,500 Ncm for industrial blending.
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The Benefit: This wide granularity allows us to match the drive train to the shaft length, minimizing the "pendulum weight" on the top nozzle.
The Interface: Plug-In Simplicity
We have standardized the most versatile interface for top-mounted applications.
- The Solution (F2 - Plug-In Can): Our standard design utilizes a Plug-In Containment Shell.
- The Advantage: This design allows the hermetic shell to be inserted through the nozzle and bolted to the existing DIN or ANSI flange. It eliminates the need for welding, making it the perfect "Drop-In" retrofit for upgrading legacy vessels from mechanical seals to magnetic drives.
Impeller & Connection Logic
We adapt the mixing element to the process goal, but mechanics dictates the assembly.
- The Geometry: Whether you require Low-Shear Suspension (Marine Propeller) or Gas Dispersion (Rushton Turbine), we calculate the optimal impeller diameter based on your process data.
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The Connection: The method of attaching the impeller to the shaft (Welded vs. Detachable) is not a simple catalog choice. It is strictly limited by the shaft dimensions and the nozzle diameter. Our engineering team determines the viable connection type to ensure mechanical stability and installation feasibility.
Drive Technology (The Headroom Solvers).
When top-mounting, vertical clearance is often the enemy. We offer a range of drive architectures to solve your specific layout constraints:
- Low-Profile Solutions: For skids with limited ceiling height, we can deploy compact planetary gear systems that significantly reduce the vertical footprint compared to standard worm gears.
- Cleanroom & Safety: For open cleanrooms or hazardous zones, we configure the drive with Stainless Steel housings or Pneumatic motors for explosion-proof safety. Consult our engineering team to define the exact drive architecture for your zone.
Surface Perfection as Standard
Because top-mounted shafts are difficult to inspect manually, the surface finish must be flawless.
- The Standard: We do not compromise on the finish. All wetted parts are supplied with a surface roughness of Ra < 0.4 µm, finished with Electropolishing (E2). This ensures maximum cleanability and corrosion resistance for the long, suspended shaft.