Zuofei DHG-9023A Benchtop Forced-Air Drying Oven

Overview

The Zuofei DHG-9023A is a precision-engineered benchtop forced-air drying oven designed for routine laboratory thermal processing tasks including moisture removal, sterilization by dry heat, pre- and post-weighing sample conditioning, polymer curing, and stability testing of pharmaceutical excipients and chemical reagents. It operates on the principle of convective heat transfer: an internal centrifugal blower circulates heated air uniformly across the chamber, ensuring rapid thermal equilibration and high spatial temperature uniformity—critical for reproducible drying kinetics and validated thermal decontamination protocols. Unlike natural convection ovens, the forced-air architecture minimizes thermal gradients and significantly reduces process time, particularly for dense or stacked samples. The unit complies with fundamental thermal safety and electromagnetic compatibility requirements per IEC 61010-1 and GB/T 14710 (Chinese national standard for environmental adaptability of medical electrical equipment), making it suitable for ISO/IEC 17025-accredited laboratories performing non-clinical analytical workflows.

Key Features

• Precision microprocessor-based temperature control: Equipped with a high-resolution LCD controller offering 0.1°C setpoint resolution and real-time digital display; PID algorithm ensures stable regulation within ±1.0°C across the full operating range (RT+10°C to 250°C).
• Forced-air circulation system: Integrated rear-mounted centrifugal fan enables adjustable airflow velocity—optimizing heat transfer efficiency without compromising sample integrity or chamber cleanliness.
• Dual independent overtemperature protection: Primary thermostat and secondary mechanical cut-off switch operate in parallel; automatic power interruption occurs if either exceeds preset limit—meeting GLP-aligned safety redundancy requirements.
• Corrosion-resistant mirror-finish stainless steel chamber: SUS304 inner lining resists oxidation and cleaning agent degradation; smooth surface minimizes particle retention and facilitates validation-compliant cleaning procedures.
• Modular shelving design: Two removable, height-adjustable stainless steel trays allow flexible load configuration; tray supports are recessed to avoid airflow obstruction and ensure laminar distribution.
• Comprehensive safety integration: Built-in residual-current circuit breaker (RCCB) provides earth-leakage protection; optional auxiliary temperature controller and RS-485 interface support remote monitoring and audit-trail generation under 21 CFR Part 11 environments.

Sample Compatibility & Compliance

The DHG-9023A accommodates standard laboratory glassware (e.g., weighing bottles, Petri dishes, crucibles), metal sample pans, and inert polymer trays up to 30 cm wide. Its 28 cm chamber depth permits vertical stacking of multiple layers when using low-profile containers. The oven is routinely employed in QC labs for loss-on-drying (LOD) assays per USP , residual solvent analysis preparation (ICH Q2), and microbiological media sterilization via dry-heat depyrogenation (validated at ≥160°C for ≥2 hours). While not certified for Class II biological safety applications, its thermal performance meets ASTM E145-22 Annex A1 criteria for gravity and forced-air laboratory ovens used in materials testing. All electrical components conform to RoHS Directive 2011/65/EU and CE-marked per EMC Directive 2014/30/EU.

Software & Data Management

The base model features embedded firmware with non-volatile timer memory and cycle logging (last 10 run records stored locally). Optional RS-485 Modbus RTU interface enables integration into LabVantage, STARLIMS, or custom SCADA systems for centralized temperature logging, alarm notification, and electronic batch record (EBR) linkage. When paired with compliant data acquisition software, the system supports ALCOA+ principles—ensuring attributable, legible, contemporaneous, original, accurate, complete, consistent, enduring, and available data. Audit trail functionality (including user ID, timestamp, parameter change history) is available with licensed third-party middleware compliant with FDA 21 CFR Part 11 Annex 11 requirements.

Applications

• Moisture content determination in APIs, excipients, and herbal powders (per pharmacopoeial methods)
• Dry-heat sterilization of glassware, stainless steel tools, and powder-filled vials
• Thermal aging studies for packaging materials and adhesives
• Pre-drying of filter membranes prior to gravimetric particulate analysis
• Curing of epoxy-coated substrates and ceramic precursors
• Stabilization of hygroscopic reference standards before calibration

FAQ

What is the maximum validated sterilization temperature and dwell time for this oven?
The DHG-9023A achieves thermal stability up to 250°C; however, dry-heat sterilization validation requires user-performed IQ/OQ/PQ per ISO 17665-1 and must be documented against specific load configuration and thermocouple mapping.
Can the oven maintain ±0.5°C uniformity at 180°C?
Per manufacturer specification, chamber uniformity is rated at ±1.0°C across the working volume; tighter tolerances require chamber mapping and potential recalibration using traceable NIST-certified sensors.
Is the stainless steel interior electropolished or passivated?
The inner chamber uses standard mill-finish SUS304; electropolishing is not included as standard but can be specified for GMP-compliant installations requiring enhanced corrosion resistance.
Does the timer function interrupt power upon completion, or only trigger an audible alert?
The timer initiates automatic power cutoff and activates visual/audible indicators; no manual reset is required to terminate heating.
Are calibration certificates traceable to national standards provided with shipment?
Factory calibration reports (as-built) are included; ISO/IEC 17025-accredited calibration certificates require separate order and on-site verification by authorized metrology service providers.