Yiheng LHS Series Economical Temperature and Humidity Controlled Chamber

Overview

The Yiheng LHS Series Economical Temperature and Humidity Controlled Chamber is engineered for reliable, repeatable environmental simulation in routine quality control, stability testing, and material conditioning applications. Based on dual-loop PID control architecture, the chamber integrates independent temperature and humidity regulation systems—utilizing a refrigeration circuit with R134a-free compressor (eco-friendly refrigerant), resistive heating elements, and a stainless-steel steam generator for precise moisture delivery. Its design conforms to fundamental operational principles defined in ISO 16770 (environmental test chambers) and supports compliance workflows aligned with ICH Q1A(R2) for pharmaceutical stability studies and ASTM D4332 for conditioning of plastic and packaging materials. The chamber operates within a defined climatic envelope—optimized for non-accelerated, long-term exposure tests where reproducibility across shifts and laboratories is critical.

Key Features

• Energy-efficient, fluorine-free refrigeration system compliant with EU F-Gas Regulation (EC No. 517/2014) and China’s HCFC Phase-out Management Plan.
• Mirror-finish 304 stainless-steel interior with radius-corner construction—resistant to corrosion, easy to sanitize, and compatible with ISO 14644-1 Class 8 cleanroom maintenance protocols.
• Dual-sensor microprocessor controller with real-time display of setpoint, actual temperature, and relative humidity—supports manual ramp-and-soak operation without programming complexity.
• Imported capacitive humidity sensor (not wet-bulb assembly), offering stable calibration over extended service intervals and eliminating periodic wick replacement and water replenishment.
• Independent mechanical overtemperature cut-off circuit—fail-safe hardware limit prevents thermal runaway independent of main controller logic (optional but recommended for GLP-compliant labs).
• Standard 25 mm diameter access port on left chamber wall (excluded on LHS-150SC model) for external probe insertion, gas sampling, or cable routing—sealed with silicone grommet when unused.
• Adjustable shelf support rails allow vertical repositioning of three standard stainless-steel shelves to accommodate varied sample heights and airflow requirements.

Sample Compatibility & Compliance

The LHS series accommodates a broad range of physical sample formats—including Petri dishes, vials, blister packs, textile swatches, polymer coupons, and packaged food specimens—within its uniform airflow zone. Chamber internal geometry ensures ≥90% volume utilization while maintaining ≤±2 °C horizontal/vertical temperature gradient and ≤±8 %RH spatial humidity variation at steady state (per ISO 2859-1 sampling plan verification). It meets basic requirements for USP “Stability Testing” under long-term storage conditions (25 °C/60 %RH), and supports documentation traceability per FDA 21 CFR Part 11 when paired with optional RS485 interface and validated data logging software. Note: For ICH Q5C biologics stability or accelerated testing (e.g., 40 °C/75 %RH), users must verify chamber performance qualification (IQ/OQ/PQ) against site-specific protocols prior to GxP use.

Software & Data Management

While the base unit features standalone analog/digital control, optional RS485 serial interface enables integration with third-party SCADA platforms (e.g., Ignition, WinCC) or custom Python/LabVIEW acquisition scripts using Modbus RTU protocol. Optional embedded thermal printer provides time-stamped hardcopy output of temperature/humidity trends at user-defined intervals (1 min to 24 h). All digital outputs include UTC timestamp, chamber ID, and sensor status flags—supporting audit-ready records for internal quality reviews. Data export is limited to CSV format; no proprietary binary files are generated. Firmware updates are performed via USB-to-serial adapter and require authorized service technician access—ensuring configuration integrity during regulatory inspections.

Applications

• Pharmaceutical: Long-term stability testing of APIs and finished dosage forms per ICH guidelines; excipient compatibility screening; packaging permeability assessment.
• Textiles & Polymers: Conditioning of woven/nonwoven samples prior to tensile, abrasion, or colorfastness testing (ASTM D1776, ISO 139).
• Food & Packaging: Shelf-life modeling under controlled ambient storage conditions; moisture barrier validation of laminated films and pouches.
• Electronics: Pre-conditioning of PCB assemblies before solderability or thermal cycling tests (IPC-TM-650 2.6.25).
• Academic Research: Environmental acclimation of biological specimens; hygrothermal aging of composite materials; calibration reference environment for hygrometer verification.

FAQ

Is this chamber suitable for GMP-regulated stability studies?
Yes—provided full IQ/OQ/PQ documentation is executed per your organization’s validation master plan and maintained alongside equipment logbooks. The LHS series supports 21 CFR Part 11 compliance only when used with validated data acquisition software and electronic signature controls.
What is the typical recalibration interval for the humidity sensor?
Capacitive RH sensors are factory-calibrated and exhibit drift <1.5 %RH/year under normal operating conditions. Annual verification against NIST-traceable hygrometer is recommended for regulated environments.
Can the chamber maintain 40 °C/75 %RH for accelerated testing?
No—the LHS series is rated only up to 45 °C with humidification and 85 %RH maximum. At 40 °C, achievable RH is limited to ~70 %RH due to saturation constraints; consult Yiheng technical support for alternative models (e.g., LHS-XXXHC series) if higher stress conditions are required.
Does the unit include a validation certificate?
No—factory calibration certificates are available upon request at time of order. Installation and operational qualification must be performed on-site by qualified personnel using accredited measurement standards.
How is airflow managed inside the chamber?
A centrifugal blower circulates air vertically through rear-mounted ducts and perforated top/side panels, achieving ≥15 air changes per hour. Air velocity at shelf level remains <0.3 m/s to prevent sample desiccation or vibration-induced artifacts.