WIGGENS 2760-25 Automated Liquid Nitrogen Level Control System
| Brand | WIGGENS |
|---|---|
| Origin | Germany |
| Model | 2760-25 |
| Application | Cryogenic Sample Immersion & Thermal Contraction Testing |
| Includes | 25 L LN₂ Storage Dewar, Dual Temperature Sensors, Control Unit, Transfer Tubing, Vent Line, Two Sample Supports |
| Power Supply | 24 V DC |
| Valve Type | Solenoid Valve (24 V DC) |
| Sensor Principle | Cryogenic Temperature Threshold Detection |
| Compliance | Designed for GLP-aligned laboratory environments |
Overview
The WIGGENS 2760-25 Automated Liquid Nitrogen Level Control System is an engineered solution for maintaining precise, stable liquid nitrogen (LN₂) levels within cryogenic Dewar vessels during extended low-temperature experiments. It operates on a dual-threshold temperature-sensing principle: two calibrated cryo-resistant temperature sensors—mounted at fixed vertical positions inside the Dewar—function as level proxies. Since liquid nitrogen exhibits a sharp, reproducible boiling point (−195.8 °C at 1 atm), the phase-dependent thermal signature at each sensor location provides unambiguous detection of LN₂ presence or absence. When the liquid level falls below the lower sensor, the control unit activates a 24 V DC solenoid valve integrated into the LN₂ transfer line. This allows pressurized LN₂ from the auxiliary 25 L storage tank to flow via siphon action into the Dewar until the rising meniscus reaches the upper sensor. Upon detection of the characteristic temperature drop at the upper sensor, the controller de-energizes the valve, halting inflow. This closed-loop feedback mechanism ensures continuous immersion of samples—critical for applications such as thermal contraction analysis, cryopreservation validation, and low-temperature material characterization—without manual intervention or risk of overfilling.
Key Features
- Dual-point cryogenic temperature sensing architecture for robust, drift-resistant level monitoring
- Fail-safe 24 V DC solenoid valve with rapid response time and rated for repeated cycling under cryogenic conditions
- Integrated control unit with LED status indicators for valve state, sensor activation, and system readiness
- Modular design compatible with standard WIGGENS cryogenic Dewars (e.g., models with Ø150–200 mm neck diameter)
- No external pressure source required—the system leverages inherent vapor pressure buildup in the 25 L storage Dewar for passive transfer
- Thermally insulated transfer tubing and vent line to minimize heat ingress and ensure stable boil-off management
- Two adjustable sample support racks included for consistent positioning of test specimens within the LN₂ bath
Sample Compatibility & Compliance
The 2760-25 system supports a broad range of solid and encapsulated samples—including metallic components, polymer specimens, biological vials, and calibration standards—provided they fit within the internal dimensions of the supplied Dewar (typical capacity: ~12–15 L working volume). The system does not impose chemical compatibility constraints beyond standard LN₂ handling protocols. All wetted components are constructed from stainless steel (AISI 304/316) and PTFE-lined fittings to resist embrittlement and thermal shock. While not certified to IEC 61000 or ATEX standards, the unit is designed for use in well-ventilated laboratory settings compliant with OSHA 1910.101 (compressed gases) and CGA G-5.5 (liquid nitrogen handling). Its operation aligns with GLP documentation requirements when paired with external data loggers recording valve actuation timestamps and ambient conditions.
Software & Data Management
The 2760-25 operates as a standalone hardware controller without embedded firmware or digital connectivity. However, its analog-compatible sensor outputs (standard 0–5 V or 4–20 mA optional upon request) permit integration with third-party data acquisition systems (e.g., National Instruments DAQ, LabVIEW, or Eurotherm controllers) for time-stamped logging of level events, cycle frequency, and dwell times. Users may configure audit trails for maintenance intervals (e.g., valve inspection every 5,000 cycles), sensor calibration checks (recommended semi-annually per ISO/IEC 17025 guidelines), and LN₂ consumption tracking. Though not FDA 21 CFR Part 11 compliant out-of-the-box, the system supports traceability when used in conjunction with validated electronic lab notebooks (ELNs) that capture operator entries, calibration certificates, and system uptime logs.
Applications
- Automated thermal contraction testing of engineering materials (metals, composites, ceramics) per ASTM E228 and ISO 11359-2
- Cryogenic stability assessment of pharmaceutical formulations and biologics containers
- Calibration of low-temperature thermocouples and RTDs using fixed-point LN₂ baths
- Pre-cooling protocols for superconducting magnet systems and cryo-EM sample preparation
- Long-duration cryostatic holding for metallurgical phase transformation studies
- Validation of vacuum-insulated container performance under dynamic fill conditions
FAQ
Does the 2760-25 require an external power supply for the solenoid valve?
Yes—it operates exclusively on a regulated 24 V DC input, supplied via the included power adapter.
Can the system be retrofitted to non-WIGGENS Dewars?
Yes, provided the Dewar has a minimum neck diameter of 120 mm and accommodates the sensor mounting bracket geometry; custom sensor housings are available upon request.
What is the typical cycle duration between valve activations?
Cycle frequency depends on Dewar insulation quality, ambient temperature, and sample thermal mass—typically ranging from 12 to 45 minutes under standard lab conditions (20 °C, 50% RH).
Is the 25 L LN₂ storage tank pressurized?
No—it relies on natural vapor pressure buildup (≤ 1.5 bar g) for transfer; no external pressurization or compressor is needed.
How often should the temperature sensors be recalibrated?
WIGGENS recommends annual verification against a NIST-traceable cryogenic reference thermometer; field calibration can be performed using a certified dry-well at −196 °C.
