JULABO FT Series Immersion Cooling Circulators

Overview

The JULABO FT Series Immersion Cooling Circulators are precision-engineered cryogenic temperature control systems designed for direct integration into external liquid baths, Dewar flasks, or custom reaction vessels. Unlike conventional recirculating chillers with external heat exchangers, the FT series employs a compact, high-efficiency immersion cooling head—hermetically sealed and constructed from corrosion-resistant AISI 316 stainless steel—that transfers refrigeration directly into the process medium via conductive and convective thermal exchange. This architecture eliminates intermediate fluid loops, minimizing thermal lag and enabling rapid cooldown from ambient to –90 °C or –100 °C (FT100 model) within controlled laboratory environments. The system operates on a two-stage cascade refrigeration cycle, certified for continuous duty at sub-ambient temperatures, and is engineered to maintain stable setpoints under dynamic thermal loads typical of exothermic reactions, low-temperature crystallization, or cryo-spectroscopy sample conditioning.

Key Features

• Wide operational temperature range: –100 °C (FT100) to +30 °C across five models (FT100, FT200, FT400/FT402, FT900/FT902/FT903), supporting applications from deep-cryo synthesis to mild sub-ambient stabilization.
• Digital PID temperature control with 0.1 °C display resolution and stability of ±0.5 °C (FT402) or ±1.0 °C (FT902/FT903) at setpoint—verified per DIN EN ISO 17025 traceable calibration protocols.
• Integrated external PT100 sensor (standard: 200 mm × Ø6 mm probe, 1.5 m PTFE-insulated cable) enables closed-loop feedback directly in the target bath, decoupling control accuracy from immersion depth or vessel geometry.
• Modular cooling head design: Linear lengths from 6 cm to 65 cm and diameters from Ø1.5 mm to Ø5 mm permit customization for narrow-necked glassware, high-aspect-ratio reactors, or vacuum-jacketed Dewars without compromising thermal contact integrity.
• Robust mechanical architecture: Hermetic sealing, oil-free compressors, and reinforced copper-alloy refrigerant circuits ensure long-term reliability under repeated thermal cycling between –100 °C and +30 °C.
• Compatibility with JULABO heating circulators (e.g., F25, HUBER Petite Fleur) enables dual-mode temperature control—extending system capability to full-range programmable ramping (–100 °C → +200 °C) when paired via external communication interface.

Sample Compatibility & Compliance

The FT series accommodates a broad spectrum of sample containers—including standard 1 L to 20 L Dewar flasks, jacketed glass reactors (≤Ø150 mm), and stainless-steel cryo-baths—provided the immersion depth exceeds the active cooling zone length and the medium exhibits adequate thermal conductivity (e.g., ethanol, methanol, liquid nitrogen–ethanol slushes, or silicone oils down to –50 °C). All units comply with IEC 61010-1:2010 for electrical safety in laboratory equipment and carry CE marking under the EU Machinery Directive. Refrigerant charge (R23/R134a blend) adheres to F-Gas Regulation (EU) No 517/2014. Optional documentation packages support GLP/GMP environments, including factory calibration certificates (traceable to DKD/DAkkS), IQ/OQ templates, and audit-ready maintenance logs.

Software & Data Management

FT402, FT902, and FT903 models feature an RS232 interface (standard) and optional Ethernet/USB connectivity for integration into centralized lab infrastructure. JULABO’s WinTherm software (Windows-based) enables remote setpoint programming, real-time temperature logging at 1 Hz resolution, alarm threshold configuration (deviation, sensor fault, overtemperature), and export of .csv/.txt datasets compliant with 21 CFR Part 11 requirements—including electronic signatures, audit trails, and user-access level management. Data timestamps are synchronized via NTP, and all parameter changes are logged with operator ID and timestamp—supporting FDA-regulated QC workflows and ISO/IEC 17025 accreditation.

Applications

• Cryogenic reaction control: Lithium–aluminum hydride reductions, organolithium additions, and Grignard quenching at –78 °C without dry ice handling hazards.
• Low-temperature spectroscopy: Stabilizing FTIR, Raman, or UV-Vis sample cells during kinetic studies below –40 °C.
• Material science testing: Thermal cycling of polymers, composites, or battery electrolytes under controlled sub-zero conditions per ASTM D696 and ISO 11359.
• Pharmaceutical development: Crystallization screening at –20 °C to –80 °C to isolate metastable polymorphs, aligned with ICH Q5A and USP environmental control guidelines.
• Calibration lab support: Providing stable reference temperatures for thermometer validation across –80 °C to +30 °C per ISO/IEC 17025 clause 6.4.10.

FAQ

Can the FT series be used with flammable solvents such as diethyl ether or pentane?
Yes—provided the immersion head remains fully submerged and the solvent vapor concentration in the surrounding atmosphere remains below its lower explosive limit (LEL). Units are not ATEX-certified; operation in Class I Division 1 environments requires additional engineering controls.
Is external chiller water required for condenser cooling?
No—the FT series uses air-cooled condensers with thermostatically regulated fans; no tap water or secondary coolant loop is needed.
What is the minimum recommended bath volume for stable temperature control?
For optimal thermal inertia and stability, a minimum working volume of 2 L is recommended for FT400/FT402 and 5 L for FT900/FT902/FT903 models when operating below –40 °C.
Does JULABO provide validation support for GxP environments?
Yes—IQ/OQ protocols, traceable calibration reports, and 21 CFR Part 11-compliant software validation packages are available upon request through JULABO’s Global Service Division.
How often does the refrigerant require servicing?
Under normal operation and proper installation (level mounting, unobstructed airflow), the sealed refrigeration circuit requires no scheduled refrigerant replenishment over a 10-year service life; annual performance verification is recommended.