Yiheng DHG Series Natural Convection Drying Oven

Overview

The Yiheng DHG Series Natural Convection Drying Oven is an entry-level yet rigorously engineered thermal processing instrument designed for routine laboratory drying, baking, sterilization, and moisture removal applications. Unlike forced-air ovens, this model relies exclusively on natural convection—heat transfer driven by buoyancy-induced air movement—eliminating mechanical fans and associated vibration, noise, and particulate disturbance. This passive airflow architecture ensures minimal sample agitation, making it especially suitable for heat-sensitive materials, low-volatility samples, or applications where cross-contamination from recirculated air must be avoided. The oven operates across a stable temperature range of RT+10°C to 200°C, with a certified temperature uniformity of ±0.5°C at setpoint and digital resolution of 0.1°C—performance parameters validated per ISO 17025-accredited internal calibration protocols. Its stainless steel (AISI 304) inner chamber features fully radiused corners and seamless welds, facilitating compliance with cleaning validation requirements in QC/QA environments.

Key Features

• Stainless steel (AISI 304) interior chamber with fully rounded corners for effective cleaning and residue-free maintenance—meets basic hygiene requirements for pharmaceutical and food testing labs.
• Natural convection heating system eliminates fan-driven turbulence, ensuring quiet operation (<25 dB(A)) and preserving sample integrity during prolonged thermal exposure.
• Microprocessor-based P.I.D. temperature controller with digital display, real-time deviation monitoring, and auto-tuning capability for consistent thermal stability.
• Dual-stage overtemperature protection: primary control loop with adjustable upper limit and independent mechanical safety cut-off—compliant with IEC 61010-1 Class II safety standards.
• Standard timer function (up to 9999 minutes) supports unattended batch processing; optional multi-stage programmable controller enables complex thermal profiles (7 programs × 9 steps, max 5999 min/step).
• Optional RS485 serial interface (Modbus RTU protocol) and thermal printer output support data traceability and integration into centralized lab management systems.

Sample Compatibility & Compliance

The DHG oven accommodates standard laboratory glassware (e.g., Petri dishes, weighing boats, crucibles), polymer films, filter papers, and biological tissue specimens requiring gentle dehydration. It is routinely deployed in accordance with ASTM D1654 (coating drying evaluation), ISO 712 (moisture content in cereals), and USP (sterilization by dry heat). While not classified as a GMP-grade sterilizer, its thermal consistency and documentation-ready options (via optional printer or RS485 logging) support audit readiness under FDA 21 CFR Part 11 when paired with validated procedural controls. Chamber volumes (27 L, 56 L, 96 L) are selected based on throughput needs and spatial constraints in ISO Class 7–8 cleanrooms or general-purpose analytical labs.

Software & Data Management

The base unit operates via front-panel keypad navigation with intuitive menu structure. For enhanced traceability, the optional RS485 interface allows connection to PC-based data acquisition software (e.g., LabVIEW-compatible drivers or custom SCADA clients), enabling time-stamped temperature logging, alarm event capture, and export to CSV/PDF formats. When equipped with the programmable controller, all active thermal profiles—including ramp rates, hold durations, and start delays—are stored in non-volatile memory with power-fail recovery. Audit trail functionality (user ID, timestamp, parameter change history) is implemented at firmware level to align with GLP documentation expectations.

Applications

• Residual solvent removal from synthesized organic compounds prior to NMR or HPLC analysis.
• Drying of gravimetric filters in environmental water testing (EPA Method 160.1, APHA Standard Methods 2540B).
• Baking of ceramic substrates and metal oxide precursors in materials science R&D.
• Melting point verification of waxes and polymers using controlled isothermal holds.
• Pre-sterilization conditioning of glassware and stainless steel tools in microbiology support labs.
• Moisture content determination in agricultural feedstock per AOAC 950.46.

FAQ

What is the maximum recommended operating temperature for continuous use?
The DHG series is rated for continuous operation up to 200°C; prolonged exposure above this threshold may accelerate insulation aging and compromise long-term temperature uniformity.
Is calibration certificate included with shipment?
A factory calibration report (traceable to NIM, China) is provided standard; UKAS or ISO/IEC 17025-accredited third-party calibration is available upon request.
Can the oven be used for sterilization of surgical instruments?
While capable of achieving dry-heat sterilization temperatures (e.g., 160°C for 120 min), this model lacks the chamber pressure monitoring, HEPA filtration, and validation ports required for medical device sterilization per ISO 17665; it is intended for lab-scale decontamination only.
Does the natural convection design affect temperature uniformity across the chamber?
Yes—natural convection yields vertical thermal stratification; users should avoid stacking samples and instead utilize single-layer placement on center shelves to maintain ±0.5°C uniformity as specified.
Are replacement parts such as door gaskets or heating elements available?
All critical wear components—including silicone door seals, tubular heating elements, and control board assemblies—are stocked globally and supplied with OEM part numbers for seamless service continuity.