Rotary mixer SB2/SB3

Quick Answer: The Rotary mixer SB2/SB3 is a disc-type tube rotator: tubes are clipped around a vertical disc that turns slowly on a compact base, inverting each tube end over end to mix blood samples, suspensions and reagents.

SB2 and SB3 Explained

SB2 and SB3 are model names from Stuart’s rotator range, and the product photo shows a Stuart unit with a disc crowded with capped tubes radiating from the centre. In that range the SB2 is generally described as the fixed-speed rotator and the SB3 as the variable-speed version, so the model ordered decides whether the speed can be adjusted. That choice is worth settling when the order is placed.

A fixed-speed rotator suits routine jobs where the same gentle inversion is used every time, such as keeping blood tubes mixed. A variable-speed model is useful when different protocols call for different rates, for example a slow rotation for bead binding and a faster one for resuspending a pellet.

Both designs clip tubes around a single disc turning in a vertical plane, so the tubes pass through upright and inverted positions on every revolution. The compact base also fits on a shelf in a cold room, where rotators are often used for overnight incubations.

Specifications

Applications

• Keeping anticoagulated blood tubes mixed during haematology practicals
• Overnight antibody or bead binding in a cold room
• Resuspending cell pellets gently without vortexing
• Mixing buffer and sample tubes during protein or nucleic acid preparation

Care & Handling

• Clip tubes symmetrically so the disc runs smoothly.
• Seal tubes containing biological material and check them for leaks before a long run.
• Clean the disc with a mild detergent or disinfectant and dry it before use.
• Keep liquids away from the switch and the base vents.

Why Choose LabEquip

Blood-science teaching labs and research groups choose a compact disc rotator like this for routine tube mixing, deciding between SB2 and SB3 by whether speed adjustment is needed. For bottles and larger vessels, the Rotary mixer STR4 takes interchangeable holders; both sit in General Lab Products, and model questions can go to the contact page.

Frequently Asked Questions

What is the difference between the SB2 and the SB3?

In the Stuart range the SB2 is sold as a fixed-speed rotator and the SB3 as a variable-speed rotator. Both use a disc turning in a vertical plane; choose the SB3 if your protocols need different mixing rates.

Which tubes can the disc hold?

The photo shows a disc fitted with many capped tubes. Discs are made for particular tube diameters, so match the disc to the tubes you use, such as blood collection tubes or microtubes, before ordering.

Can the rotator be used in a cold room?

Disc rotators of this size are commonly run in cold rooms for overnight binding steps. Allow the unit to dry and warm up before switching it on after bringing it back to room temperature.

Does the disc need to be fully loaded?

No, but the load should be balanced. Place tubes opposite each other and add water-filled tubes where needed so the disc turns without wobbling.

Why use a rotator rather than inverting tubes by hand?

A rotator gives every tube the same number of gentle inversions for as long as needed, frees the operator, and avoids the inconsistency of hand mixing across a large batch.

How should the rotator be cleaned?

Switch off and unplug it, remove the tubes and wipe the disc and base with a mild detergent or a suitable disinfectant. Avoid pouring liquid over the unit and let it dry fully before reuse.

Last Updated: September 2026