Magnetic Stirrer Product

Overview

A magnetic stirrer mixes a liquid by spinning a small magnet inside the vessel instead of putting a paddle into the sample. A coated PTFE Stir Bar dropped into the flask follows a magnet that turns just under the bench-top surface, so the contents are stirred without anything touching them through the glass. The hotplate version adds a heated Top Plate, letting one instrument both mix and heat a reaction.

Everything sits in a cast Chassis heavy enough to keep the unit from walking across the bench while the magnet spins. The aluminium base carries the drive, the heater, and the electronics; a molded shell closes it up and recesses the front for the controls. The operator sets a target speed and temperature on the Display Panel, drops a vessel and a PTFE stir bar onto the plate, and the controller holds both setpoints on its own.

How it works

Stirring is magnetic coupling. The Stirring Drive turns a two-pole magnet bar on a BLDC motor a few millimetres below the plate. Its field passes straight through the non-magnetic aluminium and grips the stir bar in the flask, dragging it around at the same speed. A Hall sensor feeds rotor position back to the board so the controller can lock the rpm and ramp gently — start too fast and the bar loses sync and rattles instead of spinning.

Heat comes from a resistive Heating Element clamped under the plate, switched by the Control Board. A PT100 sensor reads the plate temperature and the microcontroller drives a triac to hold the setpoint; plug a probe into the front jack and it regulates the liquid itself rather than the surface. Two independent safety layers guard against runaway heat: a resettable over-temp limiter trips first, and a one-shot Thermal Fuse cuts mains power for good if the plate ever exceeds its ceiling. The control board ties the loops together — one MCU runs the motor driver and the heater stage at once, so speed and temperature stay independent of each other.