Gilson SS-21 Silent Sifter® Rotational Sieve Analyzer

Overview

The Gilson SS-21 Silent Sifter® is a precision-engineered rotational sieve analyzer designed for standardized particle size distribution analysis in compliance with ASTM E11, ISO 3310-1, and USP <786>. Operating on the principle of controlled rotational motion combined with synchronized tapping—referred to as “rotational/tapping sieving”—the SS-21 delivers high reproducibility in dry sieve analysis across laboratories engaged in geotechnical testing, pharmaceutical granulation QC, construction materials evaluation, and mineral processing. Unlike conventional vibratory or horizontal shaker systems, the SS-21 employs dual rubber-coated stainless steel drive rollers that rotate the sieve stack while simultaneously applying calibrated mechanical taps via an integrated hammer assembly. This dual-mode action ensures efficient stratification and separation of particles ranging from 25 mm down to 20 µm (1 inch to No. 635), without compromising structural integrity of fragile aggregates or heat-sensitive powders.

Key Features

• Acoustically optimized enclosure reduces operational noise by 7–10 dB(A) compared to standard rotational sifters—enhancing workplace safety and enabling placement in shared lab environments without dedicated acoustic shielding.
• Ergonomic lever-latch door with compression gasket provides dust-tight sealing during operation, minimizing airborne respirable crystalline silica (RCS) exposure in accordance with OSHA 1910.1200 and NIOSH recommendations.
• Digital countdown timer with ±1-second accuracy supports programmable test durations up to 99 minutes; includes pause/resume functionality and audible 5-second end-of-cycle alert.
• Robust frame constructed from powder-coated ASTM A513 heavy-gauge steel tubing mounted on MDF-reinforced cabinet housing; exterior finished with impact-resistant industrial-grade paint.
• Hammer assembly fabricated from 6061-T6 aluminum alloy with UHMW polyethylene impact head—designed for wear resistance, low-mass inertia, and consistent tap energy delivery.
• Integrated floor stand with dual-locking swivel casters (2 × 5″ non-marking rubber wheels) enables safe relocation and stable positioning on level laboratory flooring.

Sample Compatibility & Compliance

The SS-21 accommodates both ASTM-standard 8″ (203 mm) and 12″ (305 mm) diameter test sieves, supporting full-height (6-stack capacity for 12″ sieves) and half-height configurations (up to 20-stack for 8″ sieves). It accepts ISO 200 mm and 300 mm frames when used with optional adapter kits. The system is validated for use with metallic (brass, stainless steel), woven-wire, and electroformed mesh sieves meeting ISO 3310-1 tolerances. All mechanical parameters—including rotational speed (typically 275 rpm), tap frequency (150 taps/min), and tap amplitude (2.5 mm)—are factory-calibrated and traceable to NIST standards. The device meets CE marking requirements for machinery (2006/42/EC) and electromagnetic compatibility (2014/30/EU), and its enclosed design supports GLP-compliant documentation of sieve analysis procedures under FDA 21 CFR Part 11 when paired with audit-trail-enabled LIMS integration.

Software & Data Management

While the SS-21 operates as a standalone electromechanical instrument with no embedded firmware or network interface, its timing and operational parameters are fully compatible with external data capture workflows. The large 0.5-inch (12.7 mm) LED display enables unambiguous visual verification of elapsed time and remaining duration—critical for manual SOP adherence in regulated environments. For digital recordkeeping, users may integrate the SS-21 into laboratory informatics platforms via external USB-connected timers or programmable logic controllers (PLCs) that log start/stop events, operator ID, sieve stack configuration, and environmental conditions (e.g., humidity, ambient temperature). Optional SSA-76 replacement controller units support RS-232 output for legacy SCADA linkage where required.

Applications

• Soil and aggregate gradation testing per ASTM D6913 and AASHTO T 27
• Pharmaceutical powder flow characterization and blend uniformity assessment per USP <786> and ICH Q5C
• Cement fineness determination (Blaine equivalent correlation via sieve residue at 45 µm)
• Coal and coke sizing for ASTM D3174 ash analysis preparation
• Recycled concrete aggregate (RCA) classification in sustainable infrastructure QA/QC
• Food-grade starch and flour particle distribution profiling under FDA Food Safety Modernization Act (FSMA) preventive controls

FAQ

What voltage configurations are available for the SS-21?

The SS-21 operates at 115 VAC / 60 Hz (model SS-21) or 230 VAC / 50 Hz (model SS-21F), with nominal current draw of 4.7 A and 5.4 A respectively.
Is the SS-21 compliant with ISO 565 and ISO 3310-1?

Yes—the SS-21 is mechanically compatible with all ISO 200 mm and 300 mm test sieves, and its tapping force and rotational dynamics meet the performance criteria outlined in ISO 3310-1 Annex B for rotational/tapping sieving apparatus.
Can the SS-21 be used for wet sieving?

No—the SS-21 is strictly a dry-sieving instrument. Its sealed cabinet and non-corrosive drive components are not rated for aqueous or solvent-based suspensions. Wet sieving requires dedicated hydraulic or ultrasonic systems.
What maintenance intervals are recommended?

Gilson recommends biannual inspection of hammer head wear, roller surface integrity, and gasket compression; annual recalibration of timer accuracy and tap frequency using certified stopwatch and stroboscopic measurement tools.
Are replacement parts traceable to original equipment specifications?

All genuine Gilson spare parts—including SSA-72 hammer assemblies, SSA-74 UHMW heads, and SSA-76 controllers—are supplied with material certifications and dimensional inspection reports conforming to ASME Y14.5 geometric tolerancing standards.