High-Capacity Magnetic Stirrer

What is the High-Capacity Magnetic Stirrer?

A high-capacity magnetic stirrer uses a larger magnet drive and a bigger work plate to mix up to 20 L of liquid in a single vessel. It is used for preparing buffers, media and reagents in bulk where a standard benchtop stirrer would decouple.

Overview

High-capacity stirrers use stronger magnets, a larger magnetic coupling area and a more powerful motor than standard models. Work plates are typically 250 to 300 mm in diameter, which accommodates large round-bottom flasks, carboys and stainless-steel tanks. Maximum stirring volume reaches 20 L of water-like liquid and some designs use long stir bars of 100 to 150 mm to maintain coupling. Speed ranges from about 100 to 1,500 rpm and closed-loop control keeps rpm stable across the load. Because large vessels are heavy, units have a reinforced top plate and rubber feet, and mass of the stirrer is higher, typically 5 to 10 kg. For media and buffer production in bioprocess development or large-batch solution preparation, this format avoids the need for overhead stirring equipment.

How does it work?

A magnetic stirrer contains a motor-driven permanent magnet, or a set of electromagnets, beneath a flat work surface. As the magnetic field rotates, it couples to a PTFE- or glass-coated stir bar placed in the vessel and pulls the bar into synchronous rotation, which creates a vortex and mixes the liquid. Speed is set by varying motor voltage or by pulse-width modulation, and digital models add a tachometer feedback loop to hold rpm constant. If the load or viscosity is too high, the bar decouples from the field and spins erratically. Bar shape, length and surface finish influence mixing efficiency, and larger bars couple better at high volumes. The work surface may be aluminum, stainless steel or glass-ceramic, chosen for chemical resistance and cleanability.

What are the key features?

• Large magnetic coupling for volumes up to 20 L
• Reinforced work plate supports heavy carboys and tanks
• Closed-loop speed control keeps rpm stable under load
• Long stir bars of 100–150 mm maintain strong coupling
• Stall detection alarm warns of stir bar decoupling
• Non-slip feet and robust housing for heavy-duty use

What are the technical specifications?

A typical high-capacity magnetic stirrer configuration offers speed range of 100–1,500 rpm, max stirring volume (water) of 20 L, work plate diameter of 250–300 mm, max stir bar length of 100–150 mm, speed control of Closed-loop digital and max load on plate of 25–30 kg. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The High-Capacity Magnetic Stirrer is used in bulk buffer and media preparation, large-volume reagent dissolution, bioprocess development solution prep, environmental sample homogenization and mixing in carboys and tanks. Across the wider Magnetic Stirrers class, laboratories also deploy it for buffer and reagent preparation, titration sample mixing and cell culture media preparation.

Which standards and certifications apply?

Relevant standards and methods include IEC 61010-1, IEC 61010-2-010, IEC 61326-1, GB 4793.1 and ISO 9001. Certification candidates for this model are CE, RoHS and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Place the stirrer on a level, vibration-free surface and keep liquids away from the vents. Start at low speed and increase gradually so the bar does not decouple and strike the vessel wall. Clean PTFE bars and plates after use, and inspect bars for chips or contamination that might carry over between runs. Magnetic fields can affect pacemakers, magnetic media and sensitive electronics, so set safe distances. Periodically verify rpm with a tachometer and record the result in the equipment log. For regulated work, include the unit in the preventive maintenance and qualification program, and check that electrical safety testing complies with IEC 61010-1 and your local requirements.

How do I select the right High-Capacity Magnetic Stirrer?

Select a high-capacity unit when batches reach 5–20 L of low-viscosity liquid and an overhead stirrer is impractical. For viscosity above about 1,000 mPa·s or volumes beyond 20 L use an overhead stirrer. Specify vessel diameter, total mass, fluid viscosity and required speed in your RFQ.

How does it compare with other Magnetic Stirrers variants?

Decide first on maximum liquid volume and viscosity, because these set the magnet strength and the largest bar that will stay coupled. Then choose between analog control, which is economical and adequate for routine mixing, and digital control with a rpm display and closed-loop regulation, which is preferred when repeatability matters. A slim profile helps where space is tight or when stirring inside hoods, while a submersible format suits incubators and cold rooms. Check speed range, particularly the low end for gentle mixing of cell cultures, plus the working surface material, IP rating of the housing and ambient temperature limits. For sensitive samples, verify that the motor does not transmit significant heat to the vessel. Specify voltage, plug type and any required explosion-protection features in your RFQ.