W.S. Tyler SS-33 Ro-Tap® II Dual-Sieve Mechanical Sieve Shaker

Overview

The W.S. Tyler SS-33 Ro-Tap® II Dual-Sieve Mechanical Sieve Shaker is an ASTM E11-23 and ISO 3310-1 compliant dry particle size analysis instrument engineered for high-reproducibility sieve fractionation under standardized laboratory and quality control conditions. Unlike single-stack shakers, the SS-33 executes two parallel, fully independent 8-inch (203 mm) sieve stack tests simultaneously—each replicating the precise Ro-Tap® motion profile defined by ASTM E323: 278 horizontal circular oscillations and 150 vertical taps per minute. This dual-channel architecture doubles throughput without compromising mechanical fidelity or regulatory traceability. The device employs a robust 1/4 HP induction motor with thermal overload protection, coupled to a hardened cam-and-lever drive train that maintains consistent amplitude and phase relationship across both stacks over extended operational cycles. Its rigid cast-iron base and bolt-down mounting capability minimize resonance-induced measurement drift, ensuring compliance with GLP/GMP environmental stability requirements.

Key Features

• Dual independent 8-inch (203 mm) full-height sieve stack stations—enabling concurrent, identical test protocols per ASTM E11, USP <786>, and ISO 3310-1
• Precision-machined cam-driven mechanism delivering repeatable 278 oscillations/min + 150 taps/min motion profile with <±0.5% cycle-to-cycle deviation
• Microprocessor-controlled digital timer (0.1–99.0 minutes, 0.1-second resolution) with auto-shutdown and non-volatile memory for method recall
• Quick-adjust sieve support plate with positive-lock clamping—accommodates standard full-height, half-height, or intermediate-height frames without tools
• Integrated vibration-dampening feet and optional acoustic enclosure compatibility (W.S. Tyler SoundShell®) for noise reduction to ≤65 dBA at 1 m
• UL/CSA-certified electrical system with voltage-flexible configurations (115V/60Hz, 230V/50Hz, 230V/60Hz) and built-in circuit protection

Sample Compatibility & Compliance

The SS-33 accepts all standard 8-inch (203 mm) diameter test sieves—including W.S. Tyler’s full-line of ASTM E11-compliant woven-wire, electroformed, and perforated metal sieves—as well as ISO 3310-1 certified equivalents (e.g., 200 mm round frames with metric aperture designations). It supports full-height, half-height, and intermediate-height sieve assemblies, enabling method flexibility for coarse aggregates (No. 4, 4.75 mm), pharmaceutical granules (No. 20–No. 100), and fine powders (No. 200–No. 635, down to 20 µm). All motion parameters are validated against ASTM E323 Annex A1 and documented in factory calibration certificates traceable to NIST standards. The unit meets FDA 21 CFR Part 11 data integrity prerequisites when paired with compliant LIMS integration via RS-232 or optional Ethernet module.

Software & Data Management

While the SS-33 operates as a standalone electromechanical instrument, its digital timer output supports external data logging via TTL-level pulse signals synchronized to start/stop events. When integrated into regulated environments, users deploy third-party audit-trail-capable software (e.g., LabWare LIMS, Thermo Fisher SampleManager) to capture timestamped test records—including operator ID, sieve stack configuration, duration, and pass/fail status per USP <786> sieve analysis workflows. Firmware updates (available via W.S. Tyler technical support portal) maintain alignment with evolving ASTM E11 revision cycles and EU Pharmacopoeia sieve testing annexes.

Applications

• Quality assurance of raw materials in cement, ceramics, and mineral processing (e.g., limestone, silica sand, kaolin)
• Pharmaceutical powder characterization per USP <786> and ICH Q5A for blend uniformity and dissolution rate prediction
• Aggregates grading in ASTM C136/C136M for asphalt and concrete mix design validation
• Food ingredient particle distribution analysis (e.g., flour, sugar, dairy powders) under AACC Method 28-10
• Research-scale fractionation of nanomaterials and catalyst supports where reproducible mechanical energy input is critical

FAQ

Does the SS-33 require periodic recalibration?
Yes—annual verification of tap count, oscillation frequency, and timer accuracy is recommended per ASTM E323 Section 8.2 and documented in internal equipment qualification records.
Can ISO 200 mm sieves be used on the SS-33?
No—the SS-33 is dimensionally engineered for 8-inch (203 mm) diameter frames only. For ISO 200 mm compatibility, the SS-30 or SS-31 models are specified.
Is the SS-33 suitable for wet sieving?
No—it is strictly designed for dry-sieving applications. Wet sieving requires pressurized liquid feed systems and corrosion-resistant construction not present in the Ro-Tap® II platform.
What sieve stack configurations are supported?
Each station accommodates up to six full-height 8-inch sieves with pan, or thirteen half-height sieves with pan—configurable independently per stack.
How is mechanical traceability maintained during routine use?
All motion parameters are mechanically fixed via hardened cam geometry; no user-adjustable variables affect oscillation/tap ratio. Calibration certificates include NIST-traceable verification reports and are supplied with each unit shipment.