Laboratory Equipment

What are Laboratory Hot Plates? 

Hot plates are one of the most useful pieces of equipment in a lab. They are used for uniformly heating and stirring samples. The hard part is choosing which hot plate to purchase or use when there are so many models to choose from. The key is choosing the hot plate that will be most suitable for your application. Here are some things to consider that will help you zone in on ‘the one’.

Size & Capacity

One of the first things to consider when choosing a hot plate is the volume of your sample. Hot plates come in a wide array of sizes and configurations. There’s the Pro Circular-top LCD Digital Hotplate Stirrer that holds up to a 3L sample, the LCD Digital Magnetic Hotplate Stirrer that holds up to a 5L sample, the Oxford BenchMate Hotplate Stirrer that holds up to a 10L sample, and another Oxford BenchMate Hotplate Stirrer that holds up to a 20L sample.

Viscosity

Viscosity refers to the thickness of the sample. When working with viscous samples, the focus should be on the stir bar. You don’t want your stir bar to become uncoupled. There’s more of a risk of this happening with more viscous samples where there is more resistance than with less viscous samples.

When stirring viscous samples, there are three things to keep in mind. These include sample size, type of stir bar, and stirring speed. When stirring more viscous samples, you want to make sure the device has a strong magnetic coupling like the Pro Circular-top LCD Digital Hotplate Stirrer.

Hot plates also come with different speeds. The Digital Hot Plate/Magnetic Stirrer has a maximum stir speed of 1500 RPM while the Analog Hot Plate Magnetic Stirrer has a maximum stir speed of 1600 RPM.

Accuracy

When choosing a stirrer, you can either go the digital route or the analog route. Ultimately, this is going to determine the accuracy of the process and for certain applications, accuracy is extremely important. Analog stirrers are generally less accurate than digital stirrers. Digital stirrers maintain a constant speed at all times, even when there is a change in the load, making the accuracy more consistent.

Temperature

There are two things to keep in mind when considering the temperature. One is the range and the other is the uniformity. Plate material affects uniformity. Aluminum plates result in better uniformity, however, ceramic plates offer better chemical resistance. If you combine the two by having a plate made from aluminum but covered in ceramic, you can have the best of both.

For hotplate stirrers, you need to make sure the temperature reaches the desired degree for your application. The Yamato MH-520 Stirrer With Hot Plate reaches a maximum hot plate temperature of 325°C while the Yamato MH-800 Stirrer With Hot Plate only reaches a maximum temperature of 250°C. 

Safety

With any lab equipment, safety is a primary concern. That’s especially true with hot plates since they can rise to such high temperatures. Some safety features to look for when choosing a hot plate include the following:

• PT sensor
• Thermally insulated housing
• Adjustable safety cutoff range
• Hot top indicator
• End of cycle alarm

The Hot Plate Magnetic Stirrer has a PT sensor to safely control the temperature. The thermally insulated housing keeps the device relatively cool to the touch. It also has an adjustable safety cutoff range and a hot top indicator. Some even have an end-of-cycle alarm like the Digital Hot Plate/Magnetic Stirrer for safety purposes or when there is little or no supervision.

Other Features

There are other features outside of safety that you will find on hot plates. Some hot plates will have all of these features and some will only have a few. Some of these features include the following:

• Backlit LED display
• Digital speed control
• PC Control with software
• Single or multi heat/stir function
• Electronic speed control
• Cycle time setting

The Pro Circular-top LCD Digital Hotplate Stirrer comes with a backlit LED display showing temperature and speed. The speed is controlled electronically for constant and consistent speed even during changes in the load. This hotplate can also be controlled using a personal computer and includes the software. The single or multi-feature allows for the use of heat only, stir only, or heat and stir together.

Conclusion

When choosing a hot plate, you want to make sure you choose one that is the most compatible with your application. Other criteria to consider include size & capacity, viscosity, accuracy, temperature, safety, and additional features.

Lab Pro offers a large variety of hot plates for all types of applications. For over 40 years, Lab Pro Inc. has been committed to delivering the highest quality chemicals, lab equipment, distance learning kits, lab supplies, and cleanroom PPE apparel to medical device companies and laboratories worldwide. To learn more, visit the biggest Lab Supply showroom in California, or contact us online or at 888-452-2776.