Yiheng DHG-9000A Natural Convection Drying Oven
| Brand | Yiheng |
|---|---|
| Origin | Shanghai, China |
| Manufacturer Type | Direct Manufacturer |
| Country of Origin | China |
| Instrument Type | General-Purpose Drying Oven |
| Temperature Range | RT+10°C to 200°C |
| Temperature Uniformity | ±0.5°C |
| Temperature Resolution | 0.1°C |
| Interior Material | Stainless Steel (304) |
| Heating Method | Natural Convection (No Forced Air Circulation) |
| Chamber Geometry | Rounded Corner Design (Internal Radius ≥ R15 mm) |
| Control System | Microprocessor-Based P.I.D Controller with Digital Display and Timer Function |
| Optional Features | Independent Over-Temperature Cut-off Protection |
| Max Step Duration | 5999 min) |
Overview
The Yiheng DHG-9000A Natural Convection Drying Oven is an entry-level, precision-engineered thermal processing instrument designed for routine laboratory drying, baking, sterilization, and moisture removal applications where airflow-induced disturbance or sample volatilization must be minimized. Unlike forced-air ovens that rely on fan-driven convection, this model utilizes passive natural convection—heat transfer governed solely by buoyancy-driven air movement within the chamber. This principle eliminates mechanical noise, vibration, and turbulent airflow, making it especially suitable for heat-sensitive biological specimens, powder-based pharmaceutical intermediates, filter papers, gravimetric residue analysis, and archival document drying where dimensional stability and minimal particle displacement are critical. The oven operates across a validated temperature range from ambient +10°C to 200°C, with a certified temperature uniformity of ±0.5°C at setpoint and a resolution of 0.1°C—enabling reproducible thermal exposure in accordance with ISO 17025-compliant calibration practices.
Key Features
- Stainless steel (AISI 304) interior chamber with seamless, radius-rounded corners (R ≥ 15 mm) to prevent dust accumulation and facilitate cleaning under GLP-compliant maintenance protocols.
- Microprocessor-controlled P.I.D temperature regulation system featuring digital LED display, adjustable timer function (up to 9999 minutes), and auto-start capability.
- Natural convection architecture ensures zero fan-generated noise and eliminates cross-contamination risk from recirculated air—critical for low-volatility sample handling per USP & EP drying guidelines.
- Dual-stage thermal safety architecture: primary P.I.D control loop plus optional independent over-temperature cut-off circuit (hardware-limited, non-software-dependent) compliant with IEC 61000-4-2 ESD immunity standards.
- Modular expansion interface supporting RS485 serial communication (Modbus RTU protocol) for integration into centralized lab data acquisition systems or LIMS environments.
- Optional multi-segment programmable controller enabling up to 7 user-defined thermal profiles, each comprising 9 sequential steps with independent temperature setpoints, dwell times (0–5999 min), and ramp rate constraints.
Sample Compatibility & Compliance
The DHG-9000A accommodates standard laboratory glassware (e.g., Petri dishes, weighing boats, crucibles), ceramic trays, stainless steel racks, and porous substrates such as filter membranes and blotting papers. Its natural convection design avoids desiccation artifacts caused by forced airflow—making it appropriate for ASTM D2240 (Shore hardness conditioning), ISO 293 (thermoplastic sheet conditioning), and pharmacopeial drying procedures outlined in USP and Ph. Eur. 2.2.27. All electrical components meet CE marking requirements under Directive 2014/30/EU (EMC) and 2014/35/EU (LVD). Optional printer output supports 21 CFR Part 11–compliant audit trails when paired with validated thermal printer firmware.
Software & Data Management
While the base unit operates via embedded firmware without PC dependency, the RS485 interface enables bidirectional communication with third-party SCADA platforms or custom Python/Node-RED scripts using standard Modbus register mapping. Temperature logging intervals, alarm thresholds, and profile execution status can be remotely queried and archived. When equipped with the optional thermal printer, real-time strip-chart recording of chamber temperature vs. time is generated—serving as raw data evidence for internal QA audits or external regulatory inspections. Firmware updates are performed via USB-to-serial adapter; no cloud connectivity or proprietary software installation is required.
Applications
- Residual solvent removal from polymer films prior to FTIR analysis
- Moisture content determination per AOAC 950.46 (gravimetric method)
- Pre-conditioning of test specimens for tensile strength testing (ASTM D638)
- Drying of microbiological culture plates before colony enumeration
- Stabilization of hygroscopic reference standards in analytical chemistry labs
- Low-temperature annealing of thin-film sensors during R&D prototyping
FAQ
Is forced-air circulation available on this model?
No—the DHG-9000A is strictly a natural convection oven. Forced-air variants are available under the Yiheng DG series.
Can the oven be calibrated internally without external equipment?
Yes—built-in calibration offset adjustment allows users to compensate for sensor drift using a traceable reference thermometer per ISO/IEC 17025 Section 6.5.2.
What is the maximum load capacity for uniform temperature distribution?
Uniformity specifications assume ≤70% chamber volume occupancy; full-load validation requires user-specific mapping per ASTM E2207.
Does the optional programmable controller support ramp-and-soak profiles?
Yes—each of the 7 stored programs supports linear ramp rates between consecutive temperature steps, with dwell times configurable to the minute.
Is the stainless steel interior electropolished or passivated?
Standard configuration uses mechanically polished AISI 304; electropolishing is available as a factory-order option (YIH-DHG-9000A-EP).
