A magnetic stirrer with an enclosed cast aluminium hotplate, independent speed and temperature controls and PTFE stir bars for mixing and heating liquids in laboratory glassware.
This magnetic stirrer with heating mixes liquid substances in chemical glassware: a rotating magnetic stir bar is placed in the vessel with the liquid, the drive of the instrument keeps it turning, and when required the sample is heated at the same time. The instrument is used in chemical laboratories, research institutions and medical and pharmaceutical establishments to prepare solutions, dilute reagents, carry out extraction and run other processes that need heating and stirring to be combined.
The instrument has two independent rotary controls, one for the rotation speed of the stir bar and one for the temperature of the heating surface, which reaches a maximum of 280 °C. The heating surface is made of cast aluminium alloy in an enclosed design that withstands reagents spilled on it, and the height of the working plate is adjusted by a lifting knob that is locked with a catch. The rotation speed is adjustable from 0 to 1600 rpm and the stir bar turns smoothly, without splashing the liquid and without vibration, with a working vessel volume of 1 litre. The operating state is shown by an indicator light or a display depending on the version, with separate indication for the stirring mode and the heating mode, and the shape of the housing prevents accidental contact with the hot surface. A removable stand holder about 300 mm long is attached to the housing, and a thermometer or a pH probe is fixed in its clamp so that the temperature of the liquid is measured directly in the vessel. The instrument is powered from a 220 V, 50/60 Hz mains supply through an earthed socket, and the housing is metal with a resistant coating and may be wiped with a dry or slightly damp cloth. Operating conditions are an air temperature of +5 to +40 °C and a relative humidity of 40 to 60 % without condensation. The service life is 5 years and the warranty period is 12 months.
The set includes the magnetic stirrer with heater — 1 pc, a set of magnetic stir bars — 3 pcs of different sizes, namely C5/B6 by 15 mm, C6/B7 by 20 mm and C6/B8 by 25 mm, all made of PTFE fluoroplastic for chemical resistance, a removable stand with a holder for a thermometer or a pH probe — 1 pc, a power cord with a plug — 1 pc, the passport with the warranty card — 1 pc, and individual transport packaging — 1 pc. The instrument is supplied assembled and needs no setting up before use, and additional stir bars compatible with the model may be purchased separately; the stir bars are taken out of the vessel for washing without dismantling the instrument.
Before work the instrument is placed on a horizontal, stable, vibration-free table surface at a safe distance from the edge, the working plate is set to the convenient height by turning the lifting knob and locked with the catch, a stir bar of the size matching the volume and type of the liquid is chosen, the vessel with the liquid is put in the centre of the working plate and the stir bar is placed in the centre of its bottom. The power cord is then connected to an earthed socket and the power switch is set to the on position, at which the indicator lamp lights and the position of the stir bar is checked so that it does not touch the walls of the vessel. The STIR knob sets the rotation speed, starting from a low speed and increasing gradually to the value required, with a maximum rotation speed of 1600 rpm, and the stirring indicator is lit during operation. The HEAT knob sets the temperature to a maximum of 280 °C and is pressed in fully to activate heating, which is shown by a red indicator, after which several minutes are allowed for the liquid to reach the temperature required. A thermometer or a pH probe fixed in the holder of the removable stand is immersed in the liquid so that its temperature is read directly, and the position of the HEAT knob is corrected according to the readings.
At the end of the work the rotation speed is reduced slowly to zero, heating is switched off, the power switch is set to the off position, the instrument is left to cool to a safe temperature before anything is dismantled, and the stir bar is taken out of the vessel and washed. The instrument is used by people who have been given the appropriate labour safety instruction and is not left unattended while it is running or while it is connected to the mains. It is never switched on without a stir bar in the vessel, is not operated outside the range of 0 to 1600 rpm or above the stated liquid volume, is not carried while it is heating, is not dismantled or modified, and liquid is not poured onto the housing or the plate. The working plate becomes hot during operation and direct contact with it is avoided, open flame and flammable materials are kept away from the instrument, and the mains voltage and frequency are checked against the passport data before connection. The base and the cable are never immersed in water, the plug and cable are not touched with wet hands, and a damaged cable is a reason to switch the instrument off at once. The housing is wiped with a dry or damp soft cloth, the stir bars are washed in warm water with a neutral detergent and dried, abrasive materials are not used, the contacts of the stir bar and the socket are cleaned regularly, and the cord and plug are checked once a month; apart from cleaning the instrument needs no lubrication or other maintenance.
