DRETOP DK4-30-II Benchtop Constant-Temperature Water Bath

Overview

The DRETOP DK4-30-II Benchtop Constant-Temperature Water Bath is an entry-level yet rigorously engineered thermal platform designed for precise, stable, and repeatable heating applications in analytical, biological, and pharmaceutical laboratories. It operates on the principle of resistive immersion heating coupled with microprocessor-based PID temperature regulation—ensuring minimal thermal overshoot and rapid stabilization at setpoints across its full operating range (RT + 5°C to 100°C). Unlike recirculating systems, this model employs a static bath configuration optimized for applications where uniform thermal exposure—not forced convection—is the primary requirement. Its architecture prioritizes operational safety, material longevity, and regulatory traceability, making it suitable for routine QC testing, sample conditioning prior to HPLC or spectrophotometric analysis, enzymatic reaction incubation, and controlled evaporation protocols.

Key Features

• Microprocessor-controlled PID temperature regulation with dual digital display: simultaneous readout of setpoint and actual bath temperature, resolution 0.1°C.
• High-stability thermal control system featuring a platinum resistance sensor (PT100-class equivalent) and low-drift analog signal conditioning circuitry—achieving ±0.3°C temperature stability under steady-state conditions.
• 304 stainless steel inner tank with laser-cut perforated baffle plate for enhanced heat distribution and reduced thermal stratification; electrostatically coated mild steel outer casing for corrosion resistance and mechanical durability.
• Sealed immersion heater with direct contact to bath medium—minimizing thermal lag and energy loss while enabling accurate real-time temperature feedback.
• Integrated dry-run protection: automatic heater cutoff and audible/visual alarm triggered upon detection of low water level via capacitive water-level sensor.
• Power-fail recovery function: retains user-defined parameters (setpoint, timer, alarm thresholds) during unexpected power interruption; resumes operation upon restoration of supply voltage.
• Programmable over-temperature alarm: user-definable upper-limit threshold with immediate thermal shutdown and latching alert status.
• Drain valve located at base for rapid, spill-free bath fluid replacement; compatible with deionized water, distilled water, or low-conductivity aqueous solutions (recommended for extended heater life).

Sample Compatibility & Compliance

The DK4-30-II accommodates standard laboratory glassware including beakers (up to 2 L), Erlenmeyer flasks, test tube racks (optional accessory), and reaction vessels up to 300 mm in height. Its non-circulating design eliminates shear stress on sensitive biological samples such as cell suspensions or protein solutions. While not certified for GLP/GMP environments out-of-the-box, the unit supports audit-ready documentation when used with external calibration logs and maintenance records. It complies with IEC 61010-1:2010 for electrical safety in laboratory equipment and meets CE marking requirements for EMC and low-voltage directives. For regulated workflows requiring electronic record integrity, optional RS485 interface enables integration with LIMS or SCADA systems supporting Modbus RTU protocol—facilitating time-stamped temperature logging aligned with FDA 21 CFR Part 11 principles when paired with validated software.

Software & Data Management

The DK4-30-II operates via embedded firmware without proprietary PC software dependency. All parameter configuration—including temperature setpoint, timer duration (1–9999 minutes), alarm threshold, and display brightness—is performed locally via membrane keypad and LCD interface. Optional accessories expand data handling capabilities: the RS485 communication module permits bidirectional command transmission (e.g., remote start/stop, setpoint override) and real-time temperature streaming to third-party acquisition platforms. When deployed with compliant data acquisition software, timestamped temperature traces can be exported in CSV format for inclusion in analytical reports, method validation packages, or ISO/IEC 17025-compliant uncertainty budgets. No cloud connectivity or firmware OTA updates are supported—ensuring deterministic behavior and minimizing cybersecurity surface area.

Applications

• Pre-warming reagents and solvents prior to chromatographic injection or titration procedures.
• Controlled dehydration of tissue specimens or polymer films under ambient-pressure conditions.
• Standardization of viscosity reference oils at fixed temperatures per ASTM D445 or ISO 3104.
• Incubation of microbial cultures in liquid media where agitation-induced aeration must be avoided.
• Calibration of liquid-in-glass thermometers and digital probe sensors against NIST-traceable references.
• Accelerated stability testing of pharmaceutical formulations per ICH Q1A(R2) guidelines (limited to short-term thermal stress cycles).
• Thermal equilibration of optical cuvettes before UV-Vis absorbance measurements.

FAQ

Is the DK4-30-II suitable for use with organic solvents such as ethanol or acetone?

No. This unit is rated exclusively for aqueous media. Organic solvents pose fire hazards, degrade seals, and compromise sensor accuracy due to differential thermal expansion and dielectric effects.
Can the bath temperature be logged continuously for 24 hours?

Yes—when equipped with the optional RS485 interface and connected to a compliant data logger or SCADA system, continuous timestamped readings at user-defined intervals (e.g., every 10 seconds) are achievable.
What maintenance is required to ensure long-term temperature accuracy?

Annual verification using a calibrated reference thermometer (±0.05°C uncertainty) is recommended. Clean the stainless steel tank quarterly with 1% citric acid solution to prevent scale buildup; inspect heater surface for pitting or mineral deposits.
Does the unit support cooling functionality?

No. The DK4-30-II is a heating-only system. For sub-ambient operation, DRETOP offers the R-series refrigerated baths (e.g., DK4-30-II-R), which integrate hermetic compressors and require dedicated ventilation.
Is the water-level sensor compatible with deionized water?

Yes—the capacitive sensing technology functions reliably with conductivity values ≥0.1 µS/cm, covering both distilled and Type III purified water per ASTM D1193.