Shanghai Yiheng DHG Series Natural Convection Drying Oven

Overview

The Shanghai 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 series relies on gravity-driven natural convection—heat transfer via buoyancy-induced air movement without mechanical fans. This eliminates airflow turbulence, minimizes particle resuspension, suppresses volatile loss from heat-sensitive samples, and ensures silent operation—critical in shared lab environments or cleanroom-adjacent workflows. The oven’s thermal architecture centers on a high-stability resistive heating system embedded in the chamber walls, coupled with a precisely calibrated P.I.D. temperature controller. Its operational envelope spans ambient +10°C to 200°C, supporting standard protocols for polymer drying, pharmaceutical excipient conditioning, microbiological media preparation, and pre-weighing sample stabilization per ASTM E122 and USP .

Key Features

• Stainless steel (AISI 304) interior chamber with seamless, radius-rounded corners—enhancing cleanability and reducing microbial retention points.
• Gravity convection design ensures laminar, low-velocity air circulation—ideal for powders, granules, filter papers, and coated substrates where mechanical agitation would compromise integrity.
• Microprocessor-based P.I.D. temperature controller with 0.1°C resolution and ±0.5°C stability across the full working range (RT+10°C to 200°C).
• Dual-stage safety architecture: primary P.I.D. control plus independent mechanical overtemperature cutoff (optional), interrupting power if user-defined limits are exceeded—meeting IEC 61010-1 functional safety expectations.
• Integrated timer function (0–9999 minutes) enables unattended batch processing with automatic shutdown.
• Optional RS485 communication interface (Modbus RTU protocol) supports integration into centralized lab monitoring systems for audit-ready temperature logging.
• Optional multi-segment programmable controller allows up to 7 programs × 9 steps each (63 total steps), supporting ramp-soak-hold profiles, delayed start, and staged cooling sequences—enabling compliance with thermal validation SOPs.

Sample Compatibility & Compliance

The DHG Series accommodates standard laboratory ware including porcelain crucibles, glass Petri dishes, aluminum weighing pans, and stainless steel trays. Its gentle thermal environment preserves sample morphology during low-risk dehydration—particularly suited for botanical specimens, ceramic precursors, and inert reference materials. While not certified to UL/CSA or CE for standalone medical device use, the oven conforms to baseline electrical safety (IEC 61010-1) and thermal performance expectations aligned with ISO 17025 clause 6.4.1 (environmental condition control). It is routinely deployed in QC labs performing residual solvent analysis (per USP ), moisture content determination (AOAC 950.46), and stability-indicating assays where thermal history must be documented and traceable.

Software & Data Management

The optional RS485 interface enables real-time temperature streaming and setpoint adjustment via third-party SCADA or LIMS platforms. When paired with compliant data acquisition software, it supports 21 CFR Part 11–aligned features—including electronic signatures, audit trails, and user-access controls—provided the host system implements these functions. The built-in LCD display logs local runtime data (current temp, setpoint, elapsed time), while the optional thermal printer provides hard-copy verification for GLP audits. No proprietary cloud platform or vendor-hosted software is required or bundled—ensuring full data sovereignty and long-term archival compatibility.

Applications

• Moisture content determination in food, feed, and soil samples (ASTM D4442, ISO 11465)
• Drying of filter membranes prior to gravimetric particulate analysis (EPA Method 13A)
• Baking of glassware and metal components before precision weighing
• Melting and solidification studies of waxes and low-melting-point polymers (e.g., paraffin, polyethylene glycols)
• Pre-conditioning of desiccants and silica gel for humidity-controlled storage
• Low-intensity sterilization of non-critical lab tools (e.g., spatulas, scoops) at ≥160°C for ≥2 hours

FAQ

Is this oven suitable for sterilization of surgical instruments?
No. This natural convection oven lacks validated steam saturation, pressure control, and biological indicator compatibility required for medical device sterilization (ISO 17665). It is appropriate only for dry-heat decontamination of non-invasive lab tools.
Can temperature uniformity be verified per ISO 17025 requirements?
Yes. The chamber geometry and thermal mass support mapping with NIST-traceable thermocouples. Users should perform initial qualification (IQ/OQ) using ≥9 probe locations per ASTM E2297–03 guidelines.
Does the optional programmable controller support alarm output signals?
Yes—the controller includes relay outputs configurable for high-temp alerts, door-open warnings, or cycle completion notifications, compatible with PLC input modules.
What is the maximum load weight per shelf?
Each standard stainless steel shelf is rated for 15 kg distributed load. Overloading may impede natural convection and degrade temperature uniformity.
Is calibration documentation included with shipment?
A factory calibration certificate (traceable to CNAS-accredited standards) is available upon request at order stage—not supplied by default.