MKN DK-8A Digital Display Electric Constant-Temperature Water Bath (Water Bath Tank)

Overview

The MKN DK-8A Digital Display Electric Constant-Temperature Water Bath (Water Bath Tank) is a precision-engineered thermal conditioning instrument designed for reliable, repeatable temperature maintenance in routine laboratory applications. Operating on the principle of convective heat transfer via liquid-phase medium (deionized water or aqueous solutions), the DK-8A maintains stable thermal environments through far-infrared heating elements coupled with proportional temperature control logic. Its stainless steel tank ensures chemical inertness and long-term structural integrity under repeated thermal cycling, while the dual-layer insulated lid minimizes evaporative loss and surface heat dissipation—critical for extended-duration assays requiring minimal thermal drift. Engineered for operation between ambient +5°C and 65°C, the unit delivers rapid thermal equilibrium (typically <15 minutes from ambient to 60°C) and achieves temperature uniformity within ±0.5°C across the working volume—validated per ASTM E2251-22 Annex A1 for liquid bath uniformity assessment.

Key Features

• Stainless steel inner tank and lid constructed from AISI 304-grade material, offering resistance to oxidation, chlorides, and mild alkaline solutions commonly encountered in sample preparation workflows.
• Far-infrared heating system provides uniform energy distribution without localized hot spots, reducing risk of sample degradation during prolonged incubation or extraction procedures.
• Digital PID-based temperature controller featuring high-stability operational amplifiers and dual-slope A/D conversion ensures resolution of 0.1°C and repeatability better than ±0.3°C over 24-hour continuous operation.
• LED digital display with real-time temperature readout enables immediate verification of setpoint adherence—essential for audit-ready documentation in regulated environments.
• Single-well configuration (450 × 300 × 170 mm internal dimensions) accommodates standard laboratory glassware including 1 L beakers, 500 mL Erlenmeyer flasks, and multi-vial racks used in dissolution testing or enzymatic reaction setups.
• Thermal insulation design reduces power consumption during steady-state operation and supports compliance with ISO 50001 energy management principles at the instrument level.

Sample Compatibility & Compliance

The DK-8A is suitable for immersion-based thermal treatment of sealed and open-container samples, including aqueous buffers, reagent solutions, biological suspensions, and low-viscosity organic solvents. It is not intended for volatile solvent use above 40°C without vapor containment measures. The unit meets mechanical safety requirements per IEC 61010-1:2010 for laboratory electrical equipment and incorporates over-temperature protection (cut-off at 70°C) conforming to EN 60519-2. While not certified for FDA 21 CFR Part 11 compliance as a standalone device, its digital logging interface (via optional RS-232 output) supports integration into validated data acquisition systems operating under GLP or GMP frameworks where electronic records are subject to ALCOA+ principles.

Software & Data Management

The DK-8A operates as a stand-alone analog-digital hybrid instrument with no embedded firmware or network connectivity. Temperature data is displayed locally via seven-segment LED and may be manually recorded for logbook entries. For automated data capture, an external data logger (e.g., Omega OM-DAQPRO-5300 series) can be interfaced using the analog voltage output (0–5 V DC corresponding to 0–100°C) available on the rear panel. This analog signal path enables traceable temperature trending in accordance with ISO/IEC 17025 clause 7.7 (monitoring of environmental conditions) when paired with time-stamped acquisition software compliant with 21 CFR Part 11 audit trail requirements.

Applications

• Controlled-temperature incubation of microbial cultures prior to plating or enumeration.
• Accelerated stability testing of pharmaceutical formulations per ICH Q1A(R3) guidelines using water-jacketed sample holders.
• Enzyme kinetics studies requiring precise thermal stabilization of reaction mixtures (e.g., amylase, protease, or phosphatase assays).
• Sample thawing and pre-warming of frozen reagents, antibodies, or cell culture media under defined thermal ramp profiles.
• Supporting gravimetric analysis workflows by maintaining constant evaporation rates during solvent removal steps.
• Calibration support for thermometers and RTDs using fixed-point reference baths traceable to NIST SRM 1750a (water triple point).

FAQ

What is the maximum recommended operating temperature for continuous use?
The DK-8A is rated for sustained operation up to 65°C. Prolonged use above this threshold may compromise seal integrity and accelerate scaling in hard-water environments.
Can this water bath be used with corrosive solutions such as strong acids or bases?
Only dilute aqueous solutions compatible with 304 stainless steel should be used. Hydrochloric acid, sodium hydroxide >1 M, or halogenated solvents are not recommended due to pitting and stress corrosion risks.
Is the temperature sensor calibrated to a national standard?
The unit ships with factory calibration verified against a Fluke 724 temperature calibrator referenced to NIST-traceable standards. End-user recalibration is possible using a certified PT100 probe and external reference source.
Does the DK-8A include a drain valve for easy maintenance?
No drain valve is integrated; emptying requires manual tilting or siphoning. Users are advised to perform weekly descaling using 5% citric acid solution to maintain thermal efficiency.
How does the dual-layer lid contribute to performance?
The air-gap insulation layer reduces convective heat loss by ~35% compared to single-layer lids, improving temperature stability and lowering power demand during overnight operation.