DK Series DK-S22 Electric Constant-Temperature Water Bath

Overview

The DK Series DK-S22 Electric Constant-Temperature Water Bath is a precision thermal platform engineered for stable, uniform heat transfer in laboratory environments. Based on resistive heating and liquid-phase thermal conduction, it maintains setpoint temperature via a stainless-steel water-filled chamber and closed-loop PID-controlled feedback. Unlike dry-block heaters or oil baths, this water bath provides superior thermal homogeneity across samples—critical for applications requiring minimal spatial temperature gradients, such as enzyme kinetics assays, cell culture incubation, reagent pre-warming, and dissolution testing. Its design conforms to fundamental thermodynamic requirements for ISO/IEC 17025-compliant calibration workflows and supports GLP-aligned experimental reproducibility when operated within specified ambient conditions (20–25 °C, <60% RH).

Key Features

• Stainless-steel inner chamber and lid (AISI 304 grade) ensure corrosion resistance, ease of cleaning, and long-term dimensional stability under repeated thermal cycling.
• Microprocessor-based digital temperature controller with dual LED display: simultaneous readout of setpoint and real-time bath temperature, enabling immediate verification of thermal compliance.
• PID auto-tuning functionality eliminates manual parameter adjustment; the system dynamically optimizes proportional, integral, and derivative gains based on load mass and ambient drift—reducing overshoot and stabilizing within ±0.5 °C over time.
• Integrated circulation pump (standard on select DK-S models) enables internal convection uniformity and—when fitted with optional external port adapters—supports recirculating coolant delivery to peripheral devices (e.g., viscometers, spectrophotometer jackets, or reaction blocks).
• Over-temperature cut-off protection and dry-run safety interlock prevent heater element damage during low-fluid or no-fluid operation.

Sample Compatibility & Compliance

The DK-S22 accommodates standard laboratory glassware including test tubes (up to Ø25 mm), centrifuge tubes, beakers (≤500 mL), and flasks (Erlenmeyer or round-bottom). Its open-bath configuration allows direct immersion of sample containers without mechanical obstruction. The unit meets CE marking requirements for electrical safety (EN 61010-1) and electromagnetic compatibility (EN 61326-1). While not certified for IEC 60529 IP ratings, its sealed control panel and elevated heater housing provide adequate protection against incidental splashing in Class II laboratory settings. For regulated environments, temperature logs generated via optional RS232 output can be archived to satisfy FDA 21 CFR Part 11 audit-trail requirements when paired with validated data acquisition software.

Software & Data Management

The DK-S22 operates as a standalone analog-digital hybrid instrument with no embedded firmware update capability. However, its RS232 serial interface (optional accessory) enables connection to host PCs running third-party LabVIEW, MATLAB, or Python-based acquisition scripts. Temperature data streams at 1 Hz resolution with ASCII-formatted output (e.g., “T=37.21°Crn”), permitting integration into centralized LIMS or ELN platforms. When used with compliant timestamping hardware, these records support traceable thermal validation per ASTM E2876-22 (Standard Guide for Thermal Validation of Water Baths) and USP (Temperature Calibration and Monitoring).

Applications

• Pre-incubation of microbiological media and molecular biology reagents (e.g., restriction enzyme buffers, agarose gels).
• Controlled-rate thawing of cryopreserved cell lines and serum aliquots to minimize thermal shock.
• Calibration of liquid-in-glass thermometers and RTD probes using fixed-point reference standards (e.g., water triple point, gallium melt).
• Accelerated stability testing per ICH Q1A(R2), where aqueous samples are held at elevated temperatures (40–60 °C) for defined durations.
• Supporting gravimetric analysis workflows by maintaining constant solvent temperature during evaporation or extraction steps.

FAQ

What is the minimum and maximum operating temperature range?
The DK-S22 maintains temperatures from ambient +5 °C to 100 °C, with optimal stability achieved between 25 °C and 85 °C.
Can this unit be used for external recirculation?
Yes—models equipped with the internal circulation pump (verify specification sheet for “Pump Option”) accept standard 10 mm OD silicone tubing via threaded NPT ports; external flow rate is limited to ≤1.2 L/min at ΔT = 10 °C.
Is calibration documentation provided with shipment?
A factory-issued temperature verification report (at 37 °C and 60 °C) is included; full ISO/IEC 17025 calibration requires third-party service.
How often should the water bath fluid be replaced?
Deionized water should be refreshed weekly under continuous use; biocide additives or glycol-water mixtures are not recommended unless validated for material compatibility.
Does the unit support programmable ramp-hold profiles?
No—the DK-S22 features only single-setpoint control; multi-step thermal protocols require external programmable controllers interfaced via RS232.