IT’S ALL A MATTER OF STIRRING: TIPS AND TRICKS TO CHOOSE THE BEST STIRRERS FOR YOUR LABORATORY

30/09/2021

Learn about stirring applications and the lab equipment solutions provided by VELP that meet your needs and laboratory requirements.

IT’S ALL A MATTER OF STIRRING: TIPS AND TRICKS TO CHOOSE THE BEST STIRRERS FOR YOUR LABORATORY

Several applications in the laboratory require stirring and many different types of lab equipment are available to perform stirring and mixing tasks.

Sample and solution preparation, water/oil bath preparation, dissolving buffers and reagents, dispersion, emulsion, homogenization. These are just some of the applications supported by various stirrers for laboratories in the food and beverage, cosmetics, pharmaceutical, chemical, paint and coatings, glue and adhesive, plastics/polymer and construction industries.

Which is the right one for your application and lab?

The variables involved when choosing the proper stirring equipment

Viscosity
Viscosity is a measure of the fluid’s resistance to flow or change in shape due to internal friction between the molecules and it is important in relation to the effort required to stir the medium. Water-like samples are perfectly stirred by magnetic stirrers, while higher viscosity mixing requires the use of overhead stirrers. This is especially true for applications where the sample’s viscosity increases as the stirring progresses, such as lotions or polymerizations. The more viscous the sample to be stirred, the more torque is required. Viscosity and torque specifications are critical when choosing the right overhead stirrer.

Volume
Magnetic stirrers are perfect to stir water-like volumes up to 20 liters for standard bench models or up to 50 liters for higher volumes. Overhead stirrers instead are able to stir up to 100 liters.

Speed
Magnetic stirrers’ speed ranges from 30 rpm up to 1700 to support challenging chemical, pharmaceutical applications. However, the highest speeds might sometimes lead to decoupling and unsatisfactory stirring performance. When very low or very high speed is required to stir the sample, overhead stirrers offer more options as their speed setting can range from 6 up to 2000 rpm.

Heating requirements
Several models of magnetic stirrers feature a hot plate that enables heating of the sample during the mixing process. Overhead stirrers require separate equipment for heating.

Application based approach: the best stirring solution for your needs

While magnetic stirrers and hot plate stirrers perform low shear mixing tasks and rely on the vortex produced with the magnetic stir bar to mix liquids, overhead stirrers come with a wide range of stirring shafts that support both low and high shear stirring and different mixing motions, vortex or no vortex.

Applications that imply vigorous emulsion mixing and stirring of medium or highly viscous substances like polymers are well supported by overhead stirrers. Such equipment is suitable to replicate the conditions of production mixing to test samples intended for a larger production scale.

Magnetic stirrers and heating magnetic stirrers are usually used in the laboratory to perform several applications requiring precise and constant control of the medium’s temperature and the stirring speed.

For instance, hot plate stirrers are the most suitable solution for oil baths and chemical synthesis applications. By means of a probe, the temperature is measured within the sample, increasing control over the reaction and ensuring the unit delivers heating when necessary, avoiding overheating. The hemispheric bowl increases surface on round bottom flask leading to heat transfer efficiency.

Accessories make the difference allowing you to customize your stirring equipment based on the various tasks and applications to be performed.

High volume magnetic stirrers are designed for low-viscosity laboratory stirring applications, especially in the pharmaceutical industry:

High volumes preparations
Buffer solution preparations
Buffer preparation and WFI (Water for Injection) especially in the Downstream department
Vaccine manufacturing

Vortex mixers are commonly used to mix small vials of liquid, reagents of an assay or an experimental sample and a dilutant leveraging the orbital movement of the rubber cup.

Browse VELP wide range of solutions

The purpose of the mixing task, the related parameters and the environment drive the selection and final choice of the most suitable equipment for your application and laboratory.

VELP manufactures a wide range of solutions that meet any requirements, even the most diverse and challenging ones:

Explore the laboratory equipment line products and look for the one that helps you achieve the mixing results that you need!

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