What is an overhead stirrer? The overhead, or suspended, or mechanical stirrers are composed of a central instrument, placed on a support and of the stirring rod, which can have different stirring blades, depending on the need. These laboratory stirrers are mainly used for mixing large quantities of liquids and samples with high viscosity (mPa*s).
For almost 40 years, VELP has been a leader in the design and development of laboratory technologies and offers a complete range of rod stirrers suitable for every need of viscosity, torque and sample volume.
Velp overhead stirrers cover a wide range of applications, but it is important to choose the right model for the actual use it will have.
No problem, thanks to this guide you will be able to find the cheapest mechanical stirrer for routine mixing or the most advanced overhead stirrer on the market, with wifi connection to have all the data in the cloud.
So, do you need to mix and stirr substances? Dissolving solids in solvents? Shake viscous solutions? Continue reading!
NOTE: in contrast to magnetic stirrers, overhead stirrers are more robust and are mainly used for stirring large quantities and liquids with higher viscosity. They consist not only of stirrers and holders, but also of rods and shovels.
There are several factors to consider before choosing the perfect rod stirrer.
You can see on our 'Overhead Stirrer' category page, how easy it is to filter products by stirring speed, stirring volume, max. torque, max. viscosity. and by control features.
Let's get to know these parameters in more detail:
1. Stirring speed
Single-speed or double-speed stirrer are available. In general, you will find speed ranges between 30-2000 rpm, or double speed between 6-400 and 30-2000 rpm.
RPM stands for 'revolutions per minute' and the meaning is clear.
2. Stirring volume
Stirrers are designed to mix large quantities of sample. Be careful in which vessel you will mix your sample, bearing in mind that it may increase in volume during the reaction.
3.Max. torque
Torque is the rotational force used to turn the mixing rod. The higher the torque, the better the ability of the mechanical stirrer to maintain the rotation speed even with mixtures of high viscosity, which can increases during the reaction. Torque is also important if rods with larger diameters are to be used. A small increase in impeller diameter and speed will result in a large increase in power required for mixing. Keep in mind the equation to calculate the power required: Power = rpm3 x Diameter5.
4. Maximum viscosity
It is important to know the viscosity or resistance strength of the liquids you will be mixing. Beware that the viscosity of some samples, such as lotions or polymerizations, may increase during mixing. Try to stay wide and choose the right stirrer rod to avoid premature wear of the instrument and malfunctions.
STIRRERS FOR SIMPLE APPLICATIONS
In short:
Models:
→ ES: analog; 50...1300rpm; 15 lt; 15 Ncm; 1.000 mPa*s.
→ LS: analog; 50...2000rpm; 25 lt; 40 Ncm; 25.000 mPa*s.
→ DLS: digital; 50...2000rpm; 25 lt; 40 Ncm; 25.000 mPa*s.
→ DLH: digital; 50...2000rpm; 40 lt; 80 Ncm; 50.000 mPa*s.
→ PW: digital; 50...2000rpm; 70 lt; 120 Ncm; 100.000 mPa*s.
Do you need a complete package, with stand, clamps and rod?
→ Systems with LS
→ Sistema con DLS
STIRRERS FOR COMPLEX APPLICATIONS
In short:
Models:
→ OHS 20 Digital: analog; 30...2000rpm; 25 lt; 20 Ncm; 10.000 mPa*s.
→ OHS 40 Digital: analog; 30...2000rpm; 25 lt; 40 Ncm; 25.000 mPa*s.
→ OHS 60 Digital: digital; 30...2000rpm; 40 lt; 60 Ncm; 50.000 mPa*s.
→ OHS 100 Digital: digital; 30...1300rpm; 100 lt; 100 Ncm; 70.000 mPa*s.
→ OHS 200 Digita: digital; 6...400/30...2000 rpm; 100 lt; 200 Ncm; 100.000 mPa*s.
Models with Wifi connection to Cloud Ermes (if you want to know more→):
→ OHS 60 Advance: analog; 30...2000rpm; 40 lt; 60 Ncm; 50.000 mPa*s.
→ OHS 100 Advance: analog; 30...1300rpm; 100 lt; 100 Ncm; 70.000 mPa*s.
→ OHS 200 Advance: digital; 6...400/30...2000 rpm; 100 lt; 200 Ncm; 100.000 mPa*s.
Do you need a complete package, with stand, clamps and rod?
→ System with OHS 60 Digital
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STIRRING RODS
For the most efficient and focused results, carefully choose the stirring rod you will use with your stirrer.
VELP stirring rods are distinguished according to the type of flow (axial, tangential, radial) and stirring speed.
The choice of the stirring rod must take into consideration the power of the stirrer, the volume of the substances to be stirred and their viscosity.
Download the table with the characteristics of the rods available: VELP AGITATION RODS.
ACCESSORIES
A stable and well positioned shaft stirrer in your laboratory is essential to increase productivity and keep the safety level as high as possible.
Velp supports your particular needs with high quality accessories: aluminum and steel stands, suitably treated to resist corrosive chemical agents; clamps, band clamps and universal platforms.
ARE YOU LOOKING FOR A DISPERSER OR A HOMOGENIZER?
OV 625 Velp
Thanks to this powerful digital disperser you will be able to homogenize, emulsify, suspend and mix biological samples, pharmaceutical, cosmetic and food products, treating samples with viscosity up to 5,000 mPa s at a speed from 3,000 to 25,000 rpm.
To find out more, go to the dedicated product page Disperser OV 625 Digital Velp.
