OHAUS Guardian 5000 heating plates and stirrers

OHAUS Guardian 5000 hotplates and stirrers

The OHAUS Guardian 5000 hotplates and stirrers are modern laboratory components that are ideal for the safe and precise heating and intensive or gentle stirring of samples. Their clear unique selling point compared to similar devices is the versatile safety concept, which combines several protective functions to prevent both temperature overshoot and accidental dry running. In addition, three different temperature control modes enable fast or precise heat control, so that demanding applications in chemistry, biotechnology and industry can be carried out safely.

Powerful and versatile laboratory helpers

This next generation of heating and stirring systems impresses with its robust design and innovative sensor technology. The solid metal housing offers stability and is designed for a long service life. Certain models with ceramic plates (18 x 18 cm or 26 x 26 cm) and versions with an aluminium plate and ceramic coating (13.5 cm, round) are available for heating. Depending on the model, temperatures from 5 °C above room temperature up to a maximum of 550 °C can be reached. Thanks to the powerful SMCO magnet, the stirrer models ensure stirring speeds of up to 1800 rpm and impress with constant speed control (+/-2 %).

Integrated functions such as SafetyHeat, SmartHeat and an extended dry-running protection system prevent unintentional overheating or damage to the appliance. The digital control with backlit LCD display also allows clear reading of set and actual values so that operators are always informed about the running processes. The appliances are equipped with an RS232 interface, making it easy to transfer or extract heating and stirring parameters. Another major plus point is the ease with which the compact, rounded surface can be washed off, which is essential for hygienic laboratory environments.

The main technical features can be summarised as follows - Maximum temperature up to 550 °C (depending on model)
- Speed range from 50 to 1800 rpm (for stirring functions)
- Capacities up to 22 litres depending on version
- Intuitive LCD display with precise status indicators and warning function
- IP32 protection and optional splash guard attachments
- Various temperature and speed calibration points for improved accuracy
- CE and TÜV certification for compliance with strict safety guidelines

A unique feature is the programmable timer, which can be set from one minute to 99 hours 59 minutes. This means that plannable processes such as endothermic reactions or long-term test series can be carried out flexibly and safely. The devices also stand out thanks to the improved SmartRate system, which allows heating and stirring to be very finely controlled: from rapid heating phases for quickly reaching higher temperatures to documented and precise temperature maintenance for sensitive samples.

The integrated acoustic alarm and a visible yellow warning indicator provide additional safety when the set temperature is reached or the set time has elapsed. This is a considerable advantage, especially for complex test series, as there is no need for time-consuming checks and laboratory safety remains high. Fine adjustment via Pt100 or Pt1000 sensors also allows direct measurement of the medium temperature, which is an important precision criterion in many areas such as pH optimisation, denaturation of organic materials or acid-base titration.

Certifications and standards

All relevant model variants comply with CE and TÜV guidelines. They are also subjected to strict DIN and safety tests, guaranteeing reliability and standard-compliant operation. The robust design, combined with advanced safety systems, provides an optimal basis for regulated laboratory applications.

Application examples

- Preparation of temperature-sensitive reagents: Thanks to precise temperature control, dissolving and heating buffer solutions is much safer.
- Sterilisation of media: Fast heating allows rapid heat treatment for germ reduction tests.
- Sample analysis in biology: Slow stirring functions guarantee homogeneous mixing of cell culture media and sensitive proteins.
- pH optimisation and titrations: The precise speed and temperature combination ensures reproducible results for endothermic reactions with acids and bases.

FAQ

How is the temperature set?

The temperature and heating rates can be set precisely using the digital control panel. Three different modes (e.g. fast rise or low overshoot) allow customisation to the application.

Can the rotation speed be calibrated?

Yes, the stirring speed can be checked and calibrated using the digital display. Deviations of +/-2 % in the speed control ensure precise mixing processes.

What happens if the limit temperature is accidentally exceeded?

The SafetyHeat and SmartHeat functions switch off the appliance or reduce the power as soon as critical temperature thresholds are exceeded. This prevents damage to the appliance and sample.

How can I prevent samples from boiling out or vaporising

?

The timer with switch-off function and an acoustic alarm signalise in good time when a process has reached its end time or temperature. This effectively prevents unintentional boiling out.

Are the appliances suitable for aggressive chemicals?

The ceramic-coated plates and robust metal housing are easy to clean and can withstand many chemicals. Nevertheless, all standard laboratory safety routines and compatibility tests should be observed.

Conclusion

These heating and stirring systems combine precise temperature control, robust construction and a high level of safety in a single device. Generous capacities, different sized and coated plates as well as intelligent protection and control functions make them a universal tool for laboratories in research, education and production. With easy-to-clean surfaces, intuitive controls and precise measurement via external sensors, they are predestined for demanding users who require reliability, flexibility and safety in all process steps.