Hotplate Safety

Total Lab Supplies offer a wide range of hotplates and hotplate/stirrers.  The Stuart range is well known in laboratories and they offer some good advice on the operation of these units.

• Do not use hotplates to heat inflammable liquids.
• Never lift or carry a hotplate until it has been switched off and allowed to cool for at least 30 minutes. A hot warning light will give guidance.
• A hotplate should be carried using both hands with the fingers under the side edges.
• Never move or carry a unit with containers on the top plate or while still connected to the mains supply.
• There is a danger of liquid spillage if containers are over-filled and stirred at high speed. Always build stirrer speed slowly and never stir more rapidly than necessary
• NEVER place a cold glass vessel onto a hotplate which is already hot.

When using a ceramic hotplates like the Stuart UC152 at temperatures over 180ºC, the base of any equipment used must not make contact with the ceramic plate outside the Hot Zone or heated plate area.

The use of a Stuart SCT1 temperature controller allows accurate temperature control of aqueous and oil based samples in the laboratory and can be used in two different modes, as a precise temperature controller from 20 to 200°C or as a digital thermometer from -4 to 325°C.

Care when preparing media

Take particular care when heating liquids having a high viscosity. Viscous liquids can act as thermal insulators and can cause thermal breakage of the glassware. This is very important with media solutions as the viscosity will usually increase as the temperature rises.

• Check that the stirring action is sufficient to agitate the whole of the liquid.  Unstirred areas in the liquid can result in uneven heat transfer and “hot spots” in the glassware. This can induce thermal stress and so cause failure.
• Check the stirring action regularly to ensure that it remains adequate as the viscosity of the solution increases.
• Always use the largest magnetic follower possible and if necessary, use a mechanical overhead stirrer.
• Do not use glass vessels with thick walls, e.g. Pyrex Heavy Duty Ware or standard beakers and flasks having capacities of 5 litres or greater.
• NEVER heat glass bottles on a hotplate.
• Ensure that the heat is built up slowly to avoid localised overheating.
• Ensure the glassware is completely free from scratches or other defects.
• Place the hotplate in a tray large enough to contain the liquid in the event of glassware failure.
• Wear the appropriate safety clothing e.g. gloves, goggles, protective apron etc.

Following these guidelines using a stirrer/hotplate should ensure trouble free use.

 For all your hotplate/stirrer needs please get in touch