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1. BV Certificate ISO 9001
2. Over 20 years experience
3. Accept O/A payment.
4.Various Shapes
5.Customized

StirBars

    Magnetic stir bars are coated magnets used to stir liquids in asealed container. They can stir fluids without requiring an openingin the container. They are a popular way of stirring liquids inmodestly sized containers. Magnetic stirrers are used in chemistryand biology research, especially in medicine. Home brewers oftenuse them to help make a yeast starter.

 

Whatis a magnetic stir bar?

   A magneticstir bar is a magnet that is encased in material that won’treact with the fluid it is immersed in.  The K&J stir barmagnets included a molded layer of PTFE (a.k.a. Teflon), which isnot reactive for many liquids.

The magnet is placed within a container and made to spin with anexternal magnetic field.  Typically, this is produced by astir-plate, which has another magnet rotating underneath thecontainer.

The chief advantage of this setup is that you can stir the liquidwithout having something stick into the container.  Thecontainer can be completely sealed.  Without a spinning shaftsticking into the container, there are no worries about leaks orlubricants contaminating the fluid.

How doesit work?

A stir bar magnet is placed inside a container, immersed inthe fluid.  A separate magnet (or magnets) is placedunderneath the container, so that it attracts to the stir barmagnet.  The lower magnet is usually attached to a motor thatspins it.  If the magnets are close enough, the stir barmagnet spins inside the container.

 

How strong are thesemagnets?

The most relevant measure of a stir bar’s strength is the maximumtorque you can feel when twisting it.  Stronger torquetranslates to greater stirring ability before the magnet-to-magnetpair "slips."

The actual strength you''ll see depends on a nu

 

mber ofinterrelated factors, which is hard to quantify in a singlenumber.  important factors include:

• The size and strength of the stir bar magnet (bigger magnets arestronger)
• The size of the stir bar magnet (bigger shapes are pushing morewater, which makes them harder to turn)
• The magnets used in the stir-plate (bigger =stronger)
• The configuration of the magnets underneath the container (2magnets at the ends of the stir bar vs. a single longmagnet)
• The distance between the magnets underneath and the stirbar
• The viscosity of the fluid (how hard it is to stir