Stuart SB3 Adjustable-Speed Rotational Mixer

Overview

The Stuart SB3 Adjustable-Speed Rotational Mixer is an engineered laboratory instrument designed for controlled, low-shear rotational mixing of biological and chemical samples in tubes, flasks, and culture vessels. Unlike vortex mixers that rely on orbital oscillation, the SB3 employs a true rotary motion—rotating the entire sample platform around a central axis—to generate gentle yet consistent agitation. This principle ensures uniform suspension of cells, microorganisms, or particulates without inducing excessive shear stress or foaming, making it especially suitable for sensitive applications such as cell culture maintenance, enzymatic assays, immunoassays, and long-term incubation mixing within environmental chambers. Its operational temperature range (4–60 °C) permits integration into standard CO₂ incubators, refrigerated rooms, or warm-room environments—enabling continuous mixing under physiologically relevant conditions. The device’s robust metal chassis, precision digital speed control, and fully articulating platform provide reproducible mechanical input across diverse experimental workflows.

Key Features

• Fully adjustable 360° rotational platform enables precise orientation control—from horizontal rolling to vertical inversion—supporting both gentle resuspension and vigorous end-over-end mixing.
• Digital speed regulation (2–40 rpm) with LED display ensures accurate, repeatable rotational velocity selection; resolution is calibrated to ±1 rpm for process consistency.
• Integrated digital timer (1–999 minutes) supports unattended operation with automatic shut-off, facilitating overnight or extended-duration protocols.
• Leak-resistant molded base captures incidental spills from tubes or caps, protecting internal electronics and simplifying benchtop cleanup.
• Six standardized tube holder adapters (SB3/1 through SB3/6) accommodate common labware diameters: microtubes (10–11.5 mm), standard test tubes (9–20 mm), 50 mL centrifuge tubes (25–35 mm), and culture tubes (12 mm, 16 mm, 26 mm).
• Optional SB2/DUAL dual-level adapter allows simultaneous use of two different tube sizes on a single platform—enhancing throughput without requiring equipment duplication.
• Compact footprint (200 × 270 × 230 mm) and lightweight design (3.2 kg) support flexible placement in biosafety cabinets, incubators, or cold rooms.

Sample Compatibility & Compliance

The SB3 is compatible with glass, polypropylene, and polycarbonate tubes, vials, and flasks up to 50 mL capacity. Its low-speed rotational profile meets requirements for GLP-compliant sample homogenization where mechanical integrity and viability preservation are critical—such as microbial suspension prior to plating (per ISO 6887-1), reagent reconstitution per USP , or cell line passaging under cGMP-aligned workflows. While not certified for IEC 61010-1 Class II safety rating out-of-box, its 230 V / 50 W configuration complies with EU Low Voltage Directive (2014/35/EU) and EMC Directive (2014/30/EU) when used with grounded outlets. No hazardous substances are employed in construction per RoHS 2011/65/EU.

Software & Data Management

The SB3 operates as a standalone electromechanical system with no embedded firmware, network interface, or software dependency. All operational parameters—including speed setpoint, timer value, and elapsed time—are displayed locally via a high-contrast LED panel. For laboratories requiring audit trails under FDA 21 CFR Part 11 or ISO/IEC 17025, manual logbook entries or external timestamped video recording are recommended to document parameter settings and run duration. No data export capability is provided; however, the device’s deterministic behavior and mechanical simplicity ensure high inter-unit reproducibility across multi-site deployments.

Applications

• Maintaining aerobic cultures during incubation by enabling continuous gas exchange in loosely capped tubes.
• Resuspending pelleted cells or precipitated proteins without introducing air bubbles or denaturation.
• Homogenizing viscous reagents (e.g., agarose solutions, antibody conjugates) prior to dispensing.
• Facilitating antigen–antibody binding kinetics in ELISA plate preparation workflows.
• Supporting dissolution testing of slow-release pharmaceutical formulations under controlled thermal conditions.
• Preparing uniform suspensions of soil or sediment samples for environmental microbiology analysis (ASTM D5030).

FAQ

Can the SB3 be operated inside a CO₂ incubator?
Yes—the unit is rated for continuous operation at temperatures up to 60 °C and relative humidity levels typical of standard CO₂ incubators (up to 95% RH), provided adequate ventilation prevents condensation buildup on electronic components.
Is speed calibration traceable to national standards?
Stuart provides factory calibration documentation upon request; users may verify rotational speed using a non-contact optical tachometer referenced to NIST-traceable standards.
Does the SB3 support programmable multi-step protocols?
No—it features single-setpoint speed and timer control only; complex sequences require external scheduling or manual intervention.
What maintenance is required?
Annual inspection of motor coupling integrity and cleaning of the base tray with 70% ethanol; no lubrication or internal servicing is specified by the manufacturer.
Are replacement tube holders available separately?
Yes—all six standard adapters (SB3/1 through SB3/6) and the SB2/DUAL dual holder are stocked as individual SKUs with full compatibility across SB3 units manufactured since 2015.