Before beginning any laboratory application, it is essential to properly prepare samples to make your work more efficient and help ensure accurate results. Sample preparation step may require heating and/or stirring to combine all mixture ingredients or shaking when extraction of an analyte is an inevitable step.
This preliminary preparation is equally important for all sample types in a wide range of applications, including chemical, food, pharmaceutical, and other industries.
Therefore, proper sample preparation requires the right laboratory equipment like centrifuges, shakers, mixers, and stirrers. OHAUS offers a wide range of instruments to support your sample preparation efforts, including our industry leading Hotplates Stirrers.
For Hotplate Stirrers that deliver effective stirring with precise temperature control and essential safety features, researchers and scientists all over the world trust OHAUS. The OHAUS Guardian Series of Hotplate Stirrers combine heating and stirring functionalities to streamline your sample preparation.
OHAUS provides an extensive selection of Hotplate Stirrers designed to address a wide array of laboratory needs.
One of the key considerations when choosing a hotplate stirrer is the material, shape and size of the plate. Different materials, such as ceramic and aluminum, offer distinct advantages: ceramic and ceramic-coated plates have better chemical resistance and are safer when working with corrosive chemicals. They can withstand higher temperatures up to 550 °C and can be wiped clean. The white surface of a ceramic or ceramic-coated steel-top plate is preferable for quantitative chemical analysis or other work where clear visibility of the sample color is required.
Alternatively, aluminum offers better heat distribution and will not crack or chip and will withstand accidental handling. Ceramic-coated steel also provides more uniform temperature across the heating surface with a white surface to easily view the sample. These materials have a lower maximum temperature than the full ceramic top plates.
The durable, chemical-resistant resin top plate on stir-only models provides a bright white surface for clear visibility. This long-lasting resin material will not chip or crack if mishandled.
In terms of shape preference, round-top models are ideal for biochemistry and chemistry labs that conduct complex heating and stirring applications due to their advantage of ideal heat distribution and suitability for round-bottomed glassware while saving valuable bench space.
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Round-top models also accept a wide range of aluminum block accessories that can accommodate standard vials and test tubes, especially useful for example, in organic synthesis labs. Square surfaces accommodate a larger range of container shapes and volumes. The shape choice will be indicated by the specific needs of the laboratory. Choosing the best-suited size and shape of hotplate ensures performance and adaptability to the lab’s unique experiments and uses.
The choice of plate size depends on the volume of samples to be heated and stirred, ensuring efficient mixing and temperature control. OHAUS Guardian Hot Plate Stirrers can heat and mix from 15L up to 22L, while single function specialty stirrers offer greater capacity from 25L up to 200L. Labs needing to stir multiple samples at once can choose multi-position stirrers with either 4 x 1L or 9 x 250mL options for synchronized and uniform mixing.
Other characteristics to consider when choosing the right Hotplate Stirrers are safety, ease-of-use and advanced functionality.
The flagship model
Guardian 7000 offers the most advanced safety features that maximize protection for users, labs, and samples. Guardian 7000 includes temperature probe and SmartHeat™ to allow users to limit the maximum temperature of the hotplate stirrer preventing overheating of sensitive samples - keeping the user and samples safe. These top line Hotplate Stirrers offer unique features like SmartPresence™ and SmartLink™ that protect your lab by automatically shutting off the heater if no one is detected after a user’s set “time out” period has passed or the *The Bluetooth
® link between a paired mobile device is broken. SmartRate enables fast or slow temperature and speed ramp rates for customized performances and precise applications.
The innovative Guardian 7000 was recognized with the Bronze A’Design Award at the 2022 International Design Academy awards, acknowledging OHAUS’ achievement in designing quality products of innovative design that support the scientific community.
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The new Guardian 5000 is expertly engineered with premium safety and versatility for everyday use. The Guardian 5000 models feature a large LCD display and are available with a top plate size from round top up to 10 x 10. Guardian 5000 provides a software-controlled ramp rate, ensuring secure magnetic coupling for viscous applications. You can choose whether you need a hotplate stirrer, a stirrer or a hotplate with enhanced properties from the Guardian 5000 models.
If you’re willing to sacrifice a few advanced features for cost savings, OHAUS offers the standard Guardian 3000 Hotplate Stirrers that are more than sufficient for most applications.
The Guardian 3000 includes numerous safety features, including a prominent hot top indicator, intuitive icons, and a bright LCD display with large temperature and speed settings– all designed to quickly and easily monitor performance from across the lab. The
Guardian 3000 includes numerous safety features, including a prominent hot top indicator, intuitive icons, and a bright LCD display with large temperature and speed settings– all designed to quickly and easily monitor performance from across the lab.
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For general purpose heating and stirring at an economical price the sturdy
Guardian 2000 is a reliable analog model. It is built to last with rugged metal housing, a spill-resistant design, and a smooth, chemical-resistant top plate (available in ceramic, ceramic coated steel, and resin for stir-only models) for easy cleanup.
Safety First
One of the most critical aspects of working with Hotplate Stirrers is safety. Operating at temperatures of up to 550°C requires robust safety features to prevent accidents and ensure the well-being of laboratory personnel. Guardian Hotplate Stirrers incorporate numerous innovative safety features.
All Guardian models have a hot top indicator light to protect users in the lab. This 13 mm hot top indicator light is prominently featured on all models from the Guardian 2000 to the Guardian 7000 and provides a visual reminder of the residual heat, reducing the risk of accidental contact with hot surfaces. Once the Guardian’s heater reaches 40°C, the indicator light turns on and will stay illuminated even when the Guardian power switch is turned off. Only when the Guardian’s heater temperature drops below 40°C will the indicator light shut off.
SmartHousing™ technology helps prevent accidents by minimizing the surface temperature of the housing. This helps prevent burns and ensures a safe working environment, even when the plate reaches high temperatures.
More advanced Guardian 3000/5000/7000 models include the unique SafetyHeat™ feature, an early detection system that uses two independent safety controls to monitor the electronics and stop heating before overtemperature occurs.
These safeguards, along with the previously mentioned SmartPresence™ and SmartLink™ features, position the Guardian series as a reliable and secure option for sample preparation in various laboratory settings.
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Appropriate and Optimal Usage
OHAUS Hotplate Stirrers cater to a diverse range of industries, each benefiting from specific features tailored to their requirements. For added versatility, a variety of accessories are available from OHAUS, including sectional blocks and uniblocks. With an added sectional block, an advanced OHAUS Hotplate Stirrer becomes a 3-in-1 instrument that can not only heat and stir
, but also act as a heating block.
Additional available accessories include temperature probes, clamps, stir bars, spinbars, and in-use covers.
In addition to laboratory, academic, and pharmaceutical usage, Guardian Hotplate Stirrers are also suitable for industrial settings with durable construction built to withstand heavy usage. With top plates made of ceramic and aluminum, bodies made of chemical-resistant plastic or metal, and displays of hardened glass, Guardian Hotplate Stirrers are able to stand up to frequent usage, as well as spills, drops, and most other laboratory mishaps.
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Elevate Your Lab Experience
When it comes to selecting the right hotplate stirrer for your laboratory needs, OHAUS Guardian Hotplate Stirrers emerge as the optimal choice. Combining reliability, versatility, and uncompromising safety features, these Hotplate Stirrers are engineered to enhance laboratory processes across various industries.
For more information about OHAUS Guardian Hotplate Stirrers,
contact your regional OHAUS representative.