DRETOP EHSW-6500 Precision Temperature and Humidity Controlled Weighing System

Overview

The DRETOP EHSW-6500 Precision Temperature and Humidity Controlled Weighing System is an engineered environmental chamber specifically designed for gravimetric analysis of airborne particulate matter under strictly controlled climatic conditions. It integrates a high-stability incubator enclosure with precision weighing infrastructure to meet the stringent requirements of regulatory weight-based measurement protocols—particularly those defined in HJ 836-2017 (Determination of Low-Concentration Particulate Matter in Fixed Pollution Source Exhaust Gas by Gravimetric Method) and HJ 656 (Technical Specification for Manual Monitoring of Ambient Air PM_2.5 by Gravimetric Method). The system operates on the principle of thermal and hygric equilibration: filter samples are conditioned within the chamber at user-defined temperature and relative humidity setpoints for ≥24 hours prior to weighing, thereby eliminating moisture-related mass drift and ambient thermal interference. Unlike standard incubators, the EHSW-6500 is structurally isolated from mechanical vibration sources—including its dedicated compressor unit—and incorporates acoustic-damping air circulation pathways to prevent airflow-induced micro-vibrations that compromise analytical balance performance.

Key Features

• Air-jacketed heating architecture ensures rapid, uniform thermal response while decoupling heat transfer from internal air movement—minimizing convective disturbance near the weighing pan.
• Compressor-driven refrigeration system operates independently from the heating subsystem, enabling precise bidirectional temperature control across the full 5–60°C range without thermal overshoot or hysteresis.
• Integrated humidification reservoir eliminates external water supply dependencies and reduces maintenance intervals; humidity is actively regulated via PID-controlled ultrasonic mist generation and desiccant-assisted dehumidification.
• Stainless-steel interior chamber (304 grade) and electrostatically coated exterior provide corrosion resistance, cleanability, and long-term dimensional stability under repeated RH cycling.
• Vibration-isolated work surface with multi-stage passive damping mounts accommodates analytical balances up to 30 kg capacity; optional custom sample fixtures support standard 47 mm, 90 mm, and quartz fiber filters, as well as volumetric glassware.
• 7-inch color TFT touchscreen interface displays real-time temperature/humidity values, historical trend curves (up to 30 days), and tabular log data exportable via USB; all parameters are password-protected and audit-trail enabled.

Sample Compatibility & Compliance

The EHSW-6500 supports standardized gravimetric workflows for TSP, PM₁₀, PM_2.5, and low-concentration source emission filters per HJ 836-2017, which mandates conditioning at 20 ± 1°C and 50 ± 5% RH for ≥24 h prior to weighing. Its sealed negative-pressure chamber design prevents cross-contamination between samples and excludes ambient particulates during loading/unloading. The system complies with multiple national and international environmental test standards including GB/T 2423.3–1993 (IEC 60068-2-3, constant damp heat), GB/T 2423.4–1993 (IEC 60068-2-30, cyclic damp heat), GB/T 5170.2–1996 (temperature chamber verification), and GB/T 5170.5–1996 (humidity chamber verification). All safety circuits conform to GB 4793.1–2007 (safety requirements for electrical equipment for measurement, control, and laboratory use), incorporating dual-limit temperature cutoffs, compressor overheat protection, water-level monitoring, and ground-fault interruption.

Software & Data Management

The embedded control firmware records time-stamped temperature and humidity values at 1-minute intervals, storing ≥100,000 data points internally. Logged datasets are exportable in CSV format for integration into LIMS or statistical analysis platforms. Balance communication occurs via RS-232 or optional USB-to-serial interface, supporting native protocol translation for METTLER TOLEDO (XSR/XSE series), SARTORIUS (Entris/Secura), and OHAUS (Explorer Pro) models. Weight readings are timestamped, synchronized with chamber environmental data, and appended to the same dataset—enabling full traceability per GLP and ISO/IEC 17025 requirements. Optional firmware upgrade enables 21 CFR Part 11-compliant electronic signatures, user role-based access control, and automated report generation compliant with HJ/T 373–2007 (Quality Assurance and Quality Control for Environmental Monitoring).

Applications

• Gravimetric quantification of particulate matter collected on quartz, Teflon, or cellulose ester filters in ambient air and stack emission monitoring programs.
• Pre-weighing conditioning of reference materials and calibration standards requiring strict moisture equilibrium.
• Long-term stability testing of hygroscopic pharmaceutical powders, catalysts, and nanomaterials under defined RH profiles.
• Method validation studies supporting EPA Method 201A, ISO 12103-1, and EN 12341 compliance in third-party environmental laboratories.
• Research applications in aerosol science, atmospheric chemistry, and inhalation toxicology where mass stability of deposited particles is critical.

FAQ

What is the minimum recommended equilibration time for filter samples?
Per HJ 836-2017, a minimum of 24 hours at stabilized setpoint (20 ± 1°C / 50 ± 5% RH) is required; the EHSW-6500 achieves thermal/hygrometric stability within ≤30 minutes after door closure.
Does the system support automatic data export to laboratory information management systems (LIMS)?
Yes—CSV exports are natively supported; API-level integration with major LIMS platforms is available via optional Modbus TCP or OPC UA gateway modules.
Can the chamber accommodate large-format filters or non-standard substrates?
The internal volume (287 L) and adjustable shelf configuration permit installation of custom carriers; maximum load footprint is 560 × 790 mm with vertical clearance of 650 mm.
Is the humidification system compatible with deionized water only?
Yes—use of DI water (resistivity ≥5 MΩ·cm) is mandatory to prevent mineral deposition on ultrasonic transducers and maintain long-term RH accuracy.
What balance brands and models are certified for seamless integration?
Factory-tested compatibility includes METTLER TOLEDO XSR205, SARTORIUS Quintix224i, and OHAUS Pioneer PX224; other RS-232–enabled balances may be configured via custom protocol mapping.