The hot plate, either analog hot plates or digital hot plates, are crucial, portable, table-top devices for specific lab processes that call for heating samples. Hot plates feature an internal heating system and a flat surface. A variety of low-boiling solvents, including diethyl ether, pentane, hexane, acetone, and low-boiling petroleum ether, can be ignited by the device at temperatures up to 350 °C. Therefore, it is never advisable to heat these chemicals on a hot plate, especially in an open vessel.

A magnetic stirrer is included with some hot plates, which makes it simpler for the heated liquid to whirl continually and create a homogeneous mixture. In student laboratories, hot plates are preferred to hot tubs since the latter can overheat, spill, or catch fire. Additionally, it requires pricey mantles, takes longer to cool, and isn't compatible with all flask sizes.

Different Types of Hot Plates

Based on the design, hot plates are divided into three types:

Stirring Hot Plate

Standard Hot Plate

Magnetic Stirrer with Hot Plates  

Based on the material, hot plates are of the following types:

Polypropylene Hot Plates

Ceramic Hot Plates

Stainless Steel Hot Plates

Aluminum Hot Plates

Things to Consider When Purchasing Lab Hot Plates

Size of the Hot Plate

Hot plates come in multiple shapes and sizes. Although there are several effective mini-hotplate stirrers available for purchase, it is advised to choose a plate larger than the vessel's size you will be working with. A larger plate, however, consumes a lot of electricity and needs a three-phase power source. As a result, consider your lab's amenities while making the instrument purchase.  

Capacity

When buying a hot plate, the sample subject's heating capacity is crucial. The device's marketable capacity ranges from 20 liters to 200 liters 

Temperature Control

Hot plates have two different ways to regulate the temperature:

When temperature accuracy is not crucial, choose a hot plate with an analog thermostat.

With a digital temperature control system, you can regulate the temperature precisely and choose from various settings for the heating rate and timer.

Required Temperature

The range of temperatures for the various hot plates on the market is between 250 and 550 °C. But it's always advised to pick an instrument whose temperature range exceeds that needed to heat the sample.  

Sample Viscosity

Buy hot plates with strong drive magnets if you're working with viscous samples. Keep in mind that a larger hot plate cannot accommodate a sample with a high viscosity. A magnetically connected device lessens the possibility of the stir bar spinning out.

Safety Features

Safety is the top priority when using tools like hot plates such as analog hot plates. The device offers numerous safety features, including:

Current limit protection

Speed ramping

High-temperature setting

Safety shield

Hot top warning indicator

Probe protection

Temperature Uniformity

Buy a digital hot plate with a stirrer if you want your temperatures to be consistent. They do a fantastic job of heat distribution. A temperature meter and a surface tracker can be used to check the temperature uniformity.

Conclusion