Cole-Parmer Stir-Pak Universal Benchtop Stirrer (Model 04555-00)

Overview

The Cole-Parmer Stir-Pak Universal Benchtop Stirrer (Model 04555-00) is a precision-engineered, compact electric stirrer designed for reproducible mixing of low-to-moderate viscosity liquids in academic, pharmaceutical, and industrial laboratory settings. Utilizing a brushed DC motor coupled with an analog anodized aluminum potentiometer, this stirrer delivers stable, continuous rotational motion across a wide speed range — from standstill to 4000 rpm — with inherent mechanical simplicity and long-term operational reliability. Its design follows fundamental principles of fluid dynamics for laminar and transitional flow regimes, making it particularly suitable for applications requiring consistent shear input without cavitation or excessive turbulence, such as buffer preparation, reagent dissolution, cell suspension maintenance, and routine QC sample homogenization. The unit operates at 230 V AC, 50/60 Hz, and conforms to UL/CSA safety standards, ensuring compliance with North American electrical safety requirements.

Key Features

• Brushed DC motor with integrated LED status indicator for real-time power-on confirmation
• Anodized aluminum potentiometer offering tactile, wear-resistant speed adjustment and robust on/off switching
• Maximum torque output of 0.07 N·m — optimized for aqueous and near-aqueous systems (viscosity ≤ 100 cP)
• Interchangeable 316 stainless steel stirring shafts (standard: 9.5 × 305 mm) compatible with 8–10 mm impeller bores
• Modular mounting rod (13 × 152 mm) enabling secure attachment to standard lab stands via dual-clamp fixtures (e.g., catalog #08041-22)
• IP23 ingress protection rating — safeguarding against vertically falling droplets and solid objects ≥ 12.5 mm
• Compact footprint (83 × 133 × 165 mm) ideal for space-constrained fume hoods and benchtop workflows
• No internal cooling fan — fully enclosed TENV-style motor housing minimizes particulate generation and simplifies cleaning

Sample Compatibility & Compliance

The Stir-Pak Universal Stirrer is validated for use with non-hazardous, non-explosive liquid samples up to 100 cP viscosity under standard ambient conditions (20–25°C). It supports ASTM D1209 (color measurement), USP (compounding aseptic preparations), and ISO 8573-1 (compressed air purity) sample preparation protocols where gentle, uniform agitation is required. While not intrinsically rated for Class I Div 1 environments, its construction meets general-purpose GLP-compliant laboratory equipment criteria. All wetted components — including the standard 316 SS shaft and impeller — comply with FDA 21 CFR §177.1520 for repeated food-contact use and exhibit excellent resistance to chlorides, dilute acids, and alkaline solutions. For corrosive media, optional PTFE-coated or all-PTFE shaft-and-impeller assemblies are available (e.g., #04449-10).

Software & Data Management

This analog-controlled stirrer does not incorporate digital firmware, embedded software, or data logging capabilities. Its operation remains intentionally hardware-centric to ensure electromagnetic compatibility (EMC) in sensitive instrumentation environments and eliminate potential points of failure associated with microprocessor-based controllers. As such, it requires no software installation, driver updates, or cybersecurity validation. However, its consistent speed repeatability (±2% full-scale accuracy when calibrated per manufacturer guidelines) enables reliable integration into validated workflows governed by FDA 21 CFR Part 11 Annex 11 and EU GMP Annex 11 — provided manual speed settings are recorded contemporaneously in bound lab notebooks or electronic batch records with appropriate audit trails. Optional accessories — such as the #50007-05 speed controller — offer enhanced precision and bidirectional operation for advanced protocol execution.

Applications

• Preparation of calibration standards and reference solutions in analytical chemistry labs
• Homogenization of cell culture suspensions prior to viability assays or flow cytometry
• Mixing of pH buffers, saline solutions, and enzymatic reaction mixtures in molecular biology workflows
• Stirring of polymer precursors during solvent-based casting procedures
• Dispersion of nanoparticles in aqueous colloids for TEM sample preparation
• Supporting ASTM E2913-13 (standard practice for evaluating dispersion stability) through controlled agitation cycles
• Routine quality control testing of raw materials in pharmaceutical manufacturing (non-sterile operations)

FAQ

What is the maximum recommended viscosity for continuous operation with Model 04555-00?
For sustained operation without thermal overload or torque limitation, the unit is rated for liquids up to 100 cP at 25°C. Higher viscosities may be accommodated intermittently using lower speeds (≤1000 rpm), but prolonged use above 100 cP risks motor heating and reduced service life.
Can this stirrer be mounted on third-party lab stands?
Yes — the included 13 mm diameter mounting rod is compatible with universal dual-clamp fixtures (e.g., Cole-Parmer #08041-22) that accept support rods up to 22 mm in diameter. Custom bracket adapters are available upon request.
Is the motor thermally protected?
The brushed DC motor includes built-in thermal cutoff circuitry that interrupts power if internal winding temperature exceeds safe operating limits, preventing irreversible insulation degradation.
Does the stirrer meet RoHS or REACH compliance requirements?
Yes — all structural and electrical components comply with EU Directive 2011/65/EU (RoHS2) and Regulation (EC) No 1907/2006 (REACH), with full material declarations available under NDA upon request.
What maintenance is required for long-term reliability?
Annual inspection of brush wear and commutator cleanliness is recommended. Replacement brushes (#04555-BRUSH) are field-serviceable without disassembly of the motor housing.