Stuart SB3 Inverted Rotational Mixer

Overview

The Stuart SB3 Inverted Rotational Mixer is an engineered solution for gentle yet effective sample agitation in life science and clinical laboratories where suspension stability, gas exchange, and temperature-sensitive handling are critical. Designed around a robust inverted-axis rotational architecture, the SB3 enables continuous orbital or tumbling motion without mechanical coupling to the sample vessel—eliminating vibration transmission and minimizing shear stress on fragile biological suspensions. Its operational envelope spans 4 °C to 60 °C, permitting direct placement inside refrigerated incubators, CO₂ chambers, or heated environmental enclosures—ensuring consistent thermal conditions during prolonged mixing protocols. Unlike conventional horizontal shakers, the SB3’s pivot-mounted platform supports full 360° angular adjustment, allowing users to select motion profiles ranging from low-energy horizontal rocking (ideal for cell culture maintenance) to vigorous end-over-end inversion (optimized for reagent resuspension or immunoassay plate washing). This configurability ensures compatibility with diverse kinetic requirements across microbiology, hematology, molecular diagnostics, and bioprocess development workflows.

Key Features

• Inverted rotational drive mechanism with zero-contact sample support—reducing cross-contamination risk and preserving sample integrity
• Digitally controlled speed range of 2–40 rpm, adjustable in 1-rpm increments for precise protocol replication
• Integrated digital timer (1–999 minutes) with auto-shutdown functionality, supporting unattended overnight operation under GLP-compliant conditions
• Leak-proof polymer base plate with integrated channeling grooves—containing accidental spills from up to 50 mL tube volumes without compromising motor housing integrity
• Tool-free, snap-fit tube holder system enabling rapid changeover between six standardized configurations: 12×15 mm, 8×16 mm, 6×18 mm, 4×25 mm, 2×50 mL conical, and the optional SB3/DUAL dual-position holder for parallel processing
• Compact footprint (200×270×230 mm) and low power draw (50 W) suitable for benchtop use in biosafety cabinets or confined incubator spaces

Sample Compatibility & Compliance

The SB3 accommodates standard borosilicate glass and polypropylene tubes (4–50 mL), microcentrifuge tubes (0.5–2 mL), and flat-bottom assay plates when fitted with appropriate holders. Its sealed electronics and IP20-rated enclosure meet IEC 61010-1 safety standards for laboratory equipment. The device operates within ISO 13485-aligned manufacturing controls as supplied by Bibby Scientific (UK), and its stable rotational output supports adherence to ASTM D4093 (Standard Practice for Mixing Liquids in Laboratory Glassware) and USP environmental agitation requirements. While not intrinsically rated for hazardous locations, the SB3 is routinely deployed in ISO Class 5–7 cleanrooms and GMP-grade QC labs where traceable, repeatable mixing is required for reagent preparation, calibration standard homogenization, or blood bank sample rotation.

Software & Data Management

The SB3 operates as a standalone instrument with no embedded firmware or connectivity interfaces. All operational parameters—including speed setpoint, timer duration, and elapsed time—are displayed via a high-contrast LED panel with tactile button controls. This design prioritizes reliability, electromagnetic immunity, and audit readiness: no software validation is required per FDA 21 CFR Part 11, and all user interactions generate no electronic records—making it suitable for environments requiring minimal computerized system qualification. For laboratories implementing electronic lab notebooks (ELN), manual entry of SB3 parameters into validated platforms (e.g., LabArchives, Benchling) satisfies ALCOA+ data integrity principles when paired with signed, dated run logs.

Applications

• Maintaining uniform suspension of anaerobic bacterial cultures during extended incubation at 37 °C
• Resuspending lyophilized antibodies or recombinant proteins without foaming or denaturation
• Equilibrating temperature-sensitive ELISA reagents prior to plate dispensing
• Rotating whole blood samples pre-centrifugation to prevent clot formation in coagulation studies
• Agitating tissue homogenates during extraction protocols requiring gentle phase separation
• Supporting ASTM E2877-22-compliant mixing of reference materials used in clinical chemistry proficiency testing

FAQ

Can the SB3 be operated inside a CO₂ incubator?
Yes—the unit is rated for continuous operation at 5–60 °C and 95% RH; however, condensation management must be addressed externally per incubator manufacturer guidelines.
Is speed calibration traceable to NIST standards?
Stuart provides factory calibration certificates (optional at time of order) referencing UKAS-accredited torque and rotational speed metrology.
What maintenance is required?
No scheduled maintenance is specified; periodic cleaning of the base plate and holder contacts with 70% ethanol is recommended.
Does the SB3 comply with EU RoHS and WEEE directives?
Yes—Bibby Scientific certifies full compliance with Directive 2011/65/EU (RoHS2) and 2012/19/EU (WEEE).
Can custom tube holders be fabricated?
Third-party mechanical drawings are available under NDA; Stuart does not offer bespoke holder fabrication but supports integration via ISO-standard M4 threaded mounting points.