ROTAX 6.8 Cantilever Stirrer by VELP

Overview

The ROTAX 6.8 Cantilever Stirrer is a precision-engineered laboratory device designed for standardized, reproducible agitation of liquid–solid suspensions under controlled rotational conditions. Developed by VELP Scientifica in Italy, it operates on the principle of low-shear, continuous orbital stirring—ideal for simulating natural mixing dynamics in environmental matrices without inducing particle fragmentation or excessive turbulence. Its cantilevered drive architecture eliminates the need for central support rods or submerged motor housings, minimizing contamination risk and simplifying cleaning between samples. The system is specifically calibrated for compliance with UNI 10802 (Italian standard for leaching tests of solid waste) and DIN 38414 Part 5 (German standard for elutriation and solubility assessment of sediments), making it a validated tool for regulatory environmental testing protocols.

Key Features

• Cantilever-driven stirrer arm with corrosion-resistant polymer-coated stainless steel construction, engineered for long-term exposure to acidic, alkaline, and organic solvent environments.
• Microprocessor-controlled speed regulation from 0 to 30 rpm in 0.1-rpm increments, ensuring precise replication of standardized agitation rates required by EN 12457, EPA Method 1311 (TCLP), and ISO 17512-1.
• Integrated LCD display provides real-time feedback of setpoint and actual rotational speed, supporting audit-ready documentation in GLP-compliant laboratories.
• Automatic stall detection and immediate motor shutdown upon mechanical resistance—prevents gear damage, sample overflow, and operator intervention during unattended operation.
• Modular bottle holder configuration: accommodates either six 2-L Erlenmeyer flasks or eight 1-L bottles using VELP-supplied adapters, enabling parallel batch processing while maintaining uniform angular momentum distribution.
• Low-vibration brushless DC motor and balanced rotor assembly ensure stable operation over extended durations (up to 96 h continuous duty), critical for multi-day leaching studies.

Sample Compatibility & Compliance

The ROTAX 6.8 is optimized for heterogeneous aqueous systems containing suspended solids, sludges, sediments, compost, and municipal/industrial waste matrices. Its open-access design permits direct integration with standard glassware used in standardized leaching procedures—including DIN 38414-S5, CEN/TS 14429, and ASTM D3987. All wetted components comply with EU Regulation (EC) No 1935/2004 for materials in contact with water intended for human consumption, and the unit’s electrical safety conforms to IEC 61010-1:2010 for laboratory equipment. It supports full traceability requirements under ISO/IEC 17025:2017 for testing laboratories, including calibration certificate traceability to national metrology institutes.

Software & Data Management

While the ROTAX 6.8 operates as a stand-alone instrument, its digital control interface is compatible with VELP’s optional PC-based VELP LabSuite software (v3.2+), enabling remote parameter setting, time-stamped logging of speed profiles, and export of CSV-formatted operational logs. The software supports 21 CFR Part 11–compliant user access levels (administrator/operator), electronic signatures, and audit trail generation for FDA-regulated environmental testing workflows. All speed changes and fault events (e.g., stall detection triggers) are timestamped and stored locally in non-volatile memory for post-test forensic review.

Applications

• Determination of pollutant solubility and release kinetics from contaminated soils, dredged sediments, and landfill leachates per ISO 17512-1 and EN 12457 series.
• Standardized agitation in sequential extraction protocols (e.g., BCR method) for fractionation of heavy metals in solid environmental samples.
• Preparation of representative homogenates prior to filtration, centrifugation, or instrumental analysis (ICP-MS, HPLC-ICP-MS, ion chromatography).
• Validation of mixing efficiency in pilot-scale wastewater treatment simulations and sludge dewatering optimization studies.
• Supporting accreditation activities for ISO/IEC 17025 laboratories performing waste characterization according to national transpositions of the EU Waste Framework Directive (2008/98/EC).

FAQ

Is the ROTAX 6.8 suitable for use with aggressive solvents such as acetonitrile or hydrochloric acid solutions?

Yes—the cantilever shaft and clamp assembly are constructed from electropolished stainless steel with PTFE and EPDM seals rated for intermittent contact with pH 1–13 aqueous media and common organic solvents.
Can the stirrer be integrated into an automated lab workflow via RS-232 or USB?

Yes—optional RS-232 and USB-to-serial interfaces are available for bidirectional communication with LIMS or custom automation scripts.
Does VELP provide calibration services traceable to international standards?

Yes—VELP-certified calibration includes speed verification at three points (5, 15, and 30 rpm) with NIST-traceable tachometer validation and a documented uncertainty budget.
What maintenance is required to sustain long-term accuracy?

Annual inspection of bearing preload, belt tension (if applicable), and firmware update verification is recommended; no routine lubrication is required due to sealed motor and maintenance-free bushings.
Is the ROTAX 6.8 compliant with CE marking and RoHS directives?

Yes—it bears the CE mark and complies with Directive 2014/30/EU (EMC), 2014/35/EU (LVD), and 2011/65/EU (RoHS II).