Mixing, Stirring and Vortexing Performance

Microplate Orbital Shakers   

Notes regarding shaker processing...

Most standard 96 wellplates vortex within a few seconds at approximately 1800 RPM. 384 wellplates, including microplates, vortex around 2400 RPM. Viscous liquids require a higher RPM to vortex, sometimes at the upper limit of 3600 RPM.

Particles, pellets and granular powders will mix, and this mixing ability is very dependent on viscosity, particle size and a specific speed. If the speed is too slow, the particles remain packed or do not lift. If the RPM is too fast, the particles only vibrate. At a very specific RPM, all particles of a certain size vortex, and this is a narrow range of about +-150 RPM.

The intelligent shakers HT-91100 and HT-91108 have a special Buzz mode, where the shaker spins in one direction for a few hundred milliseconds at high speed, then instantly reverses direction and repeats. This goes on as long as you command it to. It works like a washing machine, injecting all of the energy into the well in opposite directions over and over, and the sediment or beads just loosen, break up and resuspend.

Deep wellplates vortex in a longer amount of time, nearly 4 times as long as a standard depth well plate.

Flat bottom wells definitely vortex easier than radiused concave wells.

The shakers can handle a surface load of around 200 g, and we can handle loads up to and over 3 lbs. on special orders.

 

FAQs

Are all shakers in the series identical?
Yes, the exact precision mechanism and orbital shaking technique across the product line is the same. Only the intelligent shakers HT-91100 and HT-91108 have the ability to do more than just turn on and off at a preset speed.
 
Are these shakers really that small?
The footprint size of the base of the shaker is the precise size of a standardized SBS wellplate. The shaker base will fit anywhere you put any other wellplate.
 
Where is the control box?
Using miniature electronics, all of the controls, microprocessor, and servo motor driver are built right into each shaker base. There is no external control box of any kind. The electronics are designed to work in extreme temperatures and have been hardened electrically for an industrial machine environment.
 
Where is the model to handle two or more microplates simultaneously?
We have designed the shakers to handle a single microplate at a time. They have been precision engineered to accommodate the dynamics of shaking only a single microplate. If we were to add more microplates, it would disrupt the balance and the processing consistency would be compromised. However, these shakers are so small you can easily put many together in an array very close to each other.
 
Will my liquid splash out of the wells during shaking?
Really hard to determine without a bit of research time. It depends on the fill volume, top RPM speed, square versus round well walls, viscosity of the liquid, and orbital motion size. Check out some of the videos below to see how the liquid clings to the walls and rises upwards as a vortex forms. We have designed the shakers to have almost a zero vertical motion during shaking. We want the shaking motion to be completely planar and horizontal, again, look at the videos to see how flat the shaking is. Any vertical motion causes differences in the shaking and mixing performance in that region, and you won't get consistent process results across the microplate. Our shakers are all about ultra dynamics and precision to ensure perfect and consistent mixing results across every single well in a microplate.
 
What speed RPM am I supposed to use on my liquids?
Again, it depends on all the factors mentioned just above. We can tell you that there is eventually some sweet spot of only a few hundred RPM bandwidth wide where mixing or vortex appears optimum. It usually happens again at some harmonic of the RPM value. An easy way to ensure mixing without a lot of research is to use one of the intelligent shakers to use a 10 second acceleration ramp to a very high RPM speed, and you are likely to hit the right mixing RPM along the way. Generally, mixing or vortexing occurs in less than 250 msec. Check out videos below to see this action, usually within 100 msec of startup.
 
I got the wrong orbit size, now what?
Our shakers are designed to accommodate a 0.5, 1 or 2 mm eccentric. There is no price difference between them. We have a policy to exchange the orbit sizes for you if you find a different eccentric might work better. Simply send us an email of what size you want, send the shaker back to us, and we will exchange it out and send it back at no further cost to you.
 
Where is the 3 mm orbit model?
These are very high speed shakers, with a top speed of 3570 RPM. With a 2 mm orbital motion and running to top speed, there is a huge amount of G's inserted into each well. We haven't really found an application yet that requires a 3 mm orbit, that the 1 or 2 mm orbit won't handle. The goal is to put as much energy into each well as possible, within the spatial confines of each individual well. The 2 mm orbit fits nicely within the confines of 96 wells in a microplate. You might find a 3 mm orbit on other mixers that need to do a slow mixing for large tubes or flasks, sometimes for multiple media at the same time. Our shakers are for precision vortexing at high speeds, and a 3 mm orbit just won't work here. 
 
How accurate and reliable is the homing?
Homing works by using an optical sensor looking at an index mark on the spinning motor body. When homing is commanded, usually automatically at the completion of Stop command, the motor now runs two complete turns at a very specific set speed so we know the stopping inertia will be the same every time. Only then do we look for the rising edge of the index mark, where the motor is commanded to immediately stop. This results in an exceedingly accurate X-Y planar stop position, our specs are +-0.001" (+-1 mil, +-0.0254mm), but reality is much tighter at around +-0.0002" (+-0.2 mils, +-0.0051mm). This allows you to set up accurate pipetting from high-volume well-count microplates. We have had OEM customers test just the homing cycling for millions of cycles over years, with multiple shakers, so the reliability is extreme. The homing feature is only available for the intelligent shakers, models HT-91100 and HT-91108.
 

Slow-motion video clips of various media and liquid combinations

We have done extensive research studies on various wellplates and media to show you how mixing and vortexing works. Most of these clips represent the activity in the first 100 msec of beginning shaking.

video 1


Shaker:  0-1500 RPM, 2 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, standard SBS height, round well walls, round bottom

Liquid: H2O, 0.10ml to 0.15ml volume, injected red vegetable dye

Notes: mixes good
 
 
video 2


Shaker: 0-2000 RPM, 2 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, standard SBS height, round well walls, round bottom

Liquid: H2O, 0.10ml volume, injected red vegetable dye

Notes: mixes instantly, vortexes
 
 
video 3


Shaker: 0-1000 RPM, 2 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, standard SBS height, round well walls, round bottom

Liquid: H2O, 0.10ml volume, injected red vegetable dye

Notes: does not mix
 
 
video 4


Shaker: 0-1000 RPM, 2 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, standard SBS height, round well walls, flat bottom

Liquid: H2O, 0.15ml to 0.20ml volume, injected green vegetable dye

Notes: does not mix
 
 
video 5


Shaker: 0-1500 RPM, 2 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, standard SBS height, round well walls, flat bottom

Liquid: H2O, 0.15ml to 0.20ml volume, injected green vegetable dye

Notes: mixes good
 
 
video 6


Shaker: 0-2000 RPM, 2 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, standard SBS height, round well walls, flat bottom

Liquid: H2O, 0.15ml to 0.20ml volume, injected green vegetable dye

Notes: mixes instantly, vortexes
 
 
video 7


Shaker: 0-2000 RPM, 2 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, standard SBS height, round well walls, V shape bottom

Liquid: H2O, 0.10ml to 0.15ml volume, injected blue vegetable dye

Notes: mixes instantly, vortexes
 
 
video 8


Shaker: 0-1000 RPM, 2 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, standard SBS height, round well walls, V shape bottom

Liquid: H2O, 0.10ml to 0.15mlvolume, injected blue vegetable dye

Notes: does not mix
 
 
video 9


Shaker: 0-1500 RPM, 2 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: special tube rack holding 30 tube vials, tubes have round bottoms

Liquid: H2O, 1ml volume, red vegetable dye

Notes: mixes instantly, vortexes
 
 
video 10


Shaker: 0-1500 RPM, 1 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, standard SBS height, round well walls, round bottom

Liquid: H2O, 0.10ml to 0.15ml volume, injected red vegetable dye

Notes: mixes good
 
 
video 11


Shaker: 0-2000 RPM, 1 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, tall height, square well walls, round bottom

Liquid: H2O, 0.5ml volume, various color vegetable dye

Notes: mixes instantly, vortexes
 
 
video 12


Shaker: 0-2000 RPM, 1 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, tall height, round well walls, round bottom

Liquid: H2O, 0.5ml volume, various color vegetable dye

Notes: mixes instantly, vortexes
 
 
video 13


Shaker: 0-2000 RPM, 1 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, tall height, square well walls, round bottom

Liquid: H2O, 0.3ml to 0.5ml volume, red vegetable dye

Notes: mixes instantly, vortexes. note how volume eventually rises in all wells
 
 
video 14


Shaker: 0-2000 RPM, 1 mm orbital motion, 30 durometer isolators

View: side, 600 FPS capture

Wellplate: 96 well, standard SBS height, round well walls, flat bottom

Liquid: H2O, 0.15ml to 0.20ml volume, green vegetable dye

Notes: mixes instantly, vortexes, liquid rises in all wells
 
 
video 15


Shaker: 1600 RPM, 2 mm orbital motion, 60 durometer isolators

View: end, 600 FPS capture

Wellplate: special heavy tube rack holding 30 tube vials, round bottoms

Liquid: H2O, 1ml volume

Notes: violent sloshing inside tubes
 

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