TAITEC SDN-B / EXN-B Precision Water Bath Circulator

Overview

The TAITEC SDN-B and EXN-B Precision Water Bath Circulators are compact, high-stability benchtop thermal platforms engineered for reproducible, low-volume incubation tasks in molecular biology, clinical diagnostics, and quality control laboratories. Based on resistive heating with platinum RTD feedback and PID-controlled power modulation, these units maintain precise thermal equilibrium across small liquid volumes—particularly optimized for microcentrifuge tubes (0.2–2.0 mL), PCR strips, and narrow-diameter test tubes placed at minimal immersion depth (as low as 45 mm). Unlike conventional water baths with large thermal mass and sluggish response, the SDN-B/EXN-B series employs a focused internal recirculation jet to ensure uniform temperature distribution within the bath chamber while minimizing evaporation and thermal stratification. Their design prioritizes operational safety under low-fluid conditions—eliminating tube flotation and tipping risks commonly encountered in shallow-water applications such as enzyme kinetics assays, serum inactivation, hybridization protocols, and media pre-warming.

Key Features

• Ultra-low immersion capability: Stable thermal performance at water levels as shallow as 45 mm—ideal for microvolume containers without risk of buoyancy-induced instability.
• Dual-tier precision: SDN-B offers ±0.1–0.3°C stability; EXN-B delivers enhanced accuracy of ±0.02–0.08°C via upgraded Pt1000 sensor integration and adaptive PID tuning.
• Intuitive ten-key digital interface: Enables direct 0.1°C temperature setting and real-time toggling between setpoint and actual bath temperature display.
• Programmable ON/OFF timer (EXN-B only): Adjustable from 1 minute to 99 hours 59 minutes for unattended operation during overnight incubations or scheduled thermal cycles.
• Stainless-steel fluid-contact surfaces: Entire bath chamber, tray B mounting interface, and optional insulation tray B are constructed from corrosion-resistant AISI 304 stainless steel—ensuring long-term integrity and ease of decontamination.
• Integrated safety architecture: Includes dual overheat protection (electromechanical cut-off + electronic thermal limiter), low-water-level detection, RTD fault monitoring, and automatic shutdown upon sensor disconnection or power anomaly.

Sample Compatibility & Compliance

These circulators accommodate standard microcentrifuge tubes (1.5 mL, 2.0 mL), PCR tube strips, flat-bottomed assay plates (up to 96-well format with shallow fill), and small-diameter glass test tubes (≤15 mm OD). The 45 mm minimum water level requirement ensures reliable heat transfer to vessels containing as little as 0.3 mL of solution. Units comply with fundamental electrical safety standards per JIS C 61010-1 (equivalent to IEC 61010-1) and support traceable calibration practices aligned with ISO/IEC 17025. While not inherently 21 CFR Part 11 compliant, their deterministic timer logic, non-volatile setpoint memory, and error-log-capable firmware allow integration into validated workflows where audit trails are maintained externally.

Software & Data Management

The SDN-B and EXN-B operate as standalone instruments with no embedded software stack or network interface. All operational parameters—including set temperature, timer status, and active safety flags—are displayed on a high-contrast LED screen. No proprietary drivers, USB connectivity, or cloud synchronization are provided. For regulated environments, users may document settings and runtime logs manually or integrate external data loggers (e.g., certified thermistor-based recorders) connected via analog output ports (optional accessory). Firmware updates are not field-upgradable; calibration verification is performed using NIST-traceable reference thermometers during annual maintenance.

Applications

• Enzyme activity assays requiring tight thermal control (e.g., restriction digests, ligations, phosphatase treatments).
• Serum and complement inactivation at 56°C for cell culture preparation.
• Pre-warming of agarose gels, electrophoresis buffers, and hybridization solutions prior to blotting procedures.
• In situ hybridization (ISH) incubations using the optional PF-SDM humidifying lid to maintain saturated vapor pressure above the reaction surface.
• QC testing of temperature-sensitive reagents, including lyophilized antibodies and diagnostic enzymes.
• Stability studies of biologics under accelerated thermal stress (within specified range limitations).

FAQ

What is the minimum water volume required for stable operation?
A minimum water depth of 45 mm is required—approximately 1.2 L for the standard bath chamber. This ensures full submersion of microtubes while maintaining thermal homogeneity.
Can the unit be used with oil or other non-aqueous media?
No. These models are specifically designed and validated for deionized or distilled water only. Use of oils, glycols, or organic solvents voids warranty and compromises safety mechanisms.
Is the EXN-B’s ±0.02°C stability achievable across the full temperature range?
The stated ±0.02–0.08°C stability applies primarily between 37°C and 60°C under steady-state, low-disturbance conditions. At extremes near ambient +5°C or +70°C, stability degrades toward ±0.08°C due to increased thermal gradient effects.
Does the unit include a calibration certificate?
No factory-issued calibration certificate is included. Users must perform initial verification using an accredited reference thermometer and document results per internal SOPs.
Can the PF-SDM humidifying lid be used with the SDN-B model?
Yes—the PF-SDM lid is compatible with both SDN-B and EXN-B units and enables closed-chamber humidification for ISH and RNA handling protocols.