WIGGENS 1301–1305 Automated Liquid Nitrogen Level Control System

Overview

The WIGGENS 1301–1305 Automated Liquid Nitrogen Level Control System is an engineered solution for precise, hands-free management of liquid nitrogen (LN₂) levels in open or vented Dewar flasks and biological storage tanks. It operates on a dual-threshold resistive temperature sensing principle: two calibrated PT100 RTD probes—mounted at predefined high- and low-level positions within the Dewar—detect phase-change-induced thermal resistance shifts as LN₂ evaporates or is replenished. When the liquid level falls below the lower threshold, the controller triggers a 24 V DC solenoid valve to initiate LN₂ transfer from a bulk supply tank. Filling halts automatically upon detection of the upper threshold, minimizing overfill risk, boil-off waste, and operator exposure. Designed specifically for unsealed cryogenic vessels, this system avoids pressure buildup while maintaining operational continuity in long-term sample preservation workflows—critical for biobanks, stem cell repositories, and reproductive medicine laboratories where uninterrupted ultra-low-temperature integrity is non-negotiable.

Key Features

• Dual independent PT100 RTD sensors pre-calibrated for −196 °C operation, ensuring stable and repeatable level detection across thermal cycling
• Fail-safe relay + solid-state hybrid output architecture for reliable 24 V solenoid valve control with surge protection and contact lifetime >100,000 cycles
• Integrated visual status display (LED bar graph + color-coded indicators) showing real-time fill state, alarm condition, and valve actuation status
• Configurable acoustic–visual alarm system (85 dB buzzer + flashing red LED) triggered by low-level condition, sensor fault, or valve timeout
• IP65-rated front-panel controller housing with corrosion-resistant enclosure, suitable for humid or cold-room environments (0–40 °C ambient)
• Modular component design: supports field replacement of sensors (1301/1302), valves (1303), and application-specific transfer lines (1304 for Apollo-series; 1305 for ALU/ALU-CD-series tanks)

Sample Compatibility & Compliance

The system is validated for use with standard open-neck liquid nitrogen Dewars (e.g., Taylor-Wharton, MVE, CryoStar) and pressurized but vented biological storage tanks operating under atmospheric equilibrium conditions. It does not support sealed, pressurized systems requiring closed-loop vapor-phase monitoring. All components comply with European electromagnetic compatibility (IEC 61000-6-2/6-4) and low-voltage directive (LVD 2014/35/EU) requirements. The PT100 sensors meet IEC 60751 Class B tolerance (±0.3 °C at 0 °C, extrapolated for cryogenic use). While not inherently 21 CFR Part 11 compliant, audit-ready operation logs can be generated via optional analog output integration with facility SCADA or LIMS platforms supporting GLP/GMP traceability.

Software & Data Management

This is a hardware-integrated, microcontroller-based system with no embedded OS or network stack. Configuration is performed via DIP-switch settings and front-panel push-button interface—ensuring deterministic response time (<500 ms sensor-to-valve activation) and immunity to software crashes. Analog voltage outputs (0–10 V or 4–20 mA) are available on select controller variants for connection to external data loggers or building management systems. No proprietary software installation is required; calibration verification and functional testing follow documented SOPs aligned with ISO/IEC 17025 laboratory quality standards.

Applications

• Automated replenishment of LN₂ in cryopreservation Dewars used for long-term storage of primary human cells, PBMCs, oocytes, and embryos
• Level stabilization in transport Dewars during extended transit or temporary off-site storage (e.g., clinical trial sample logistics)
• Integration into centralized cryo-facility infrastructure where multiple Apollo-, ALU-, or ALU-CD-series tanks require synchronized, low-maintenance fill scheduling
• Reduction of manual intervention in GMP-compliant biomanufacturing cleanrooms, lowering contamination risk and personnel training burden
• Supporting ISO 20387-accredited biobanking operations through consistent LN₂ level maintenance per BBMRI-ERIC best practices

FAQ

Can this system be used with pressurized liquid nitrogen tanks?
No. The 1301–1305 system is designed exclusively for open or vented Dewars and atmospheric-equilibrium storage tanks. It does not monitor headspace pressure or support closed-loop pressurization control.
What is the maximum recommended distance between controller and sensor?
For optimal signal integrity, PT100 lead length should not exceed 10 meters using shielded, twisted-pair cable (AWG 24 minimum). Longer runs require 4-wire RTD configuration and signal conditioning.
Is calibration traceable to national standards?
Yes—WIGGENS provides optional factory calibration certificates traceable to PTB (Physikalisch-Technische Bundesanstalt) upon request, including uncertainty budgets per ISO/IEC 17025.
Does the system support remote monitoring via Ethernet or Wi-Fi?
Not natively. Remote supervision requires integration via its analog output ports into third-party SCADA, BMS, or custom IoT gateways.
Are spare parts and technical documentation available globally?
All components (1301–1305) are stocked by authorized WIGGENS distribution partners in EMEA, North America, and APAC, with English-language operation manuals, wiring schematics, and CE DoC available for download via the official WIGGENS technical portal.