JULABO SL-8K / SL-14K High-Precision Temperature Calibration Bath

Overview

The JULABO SL-8K and SL-14K are high-precision temperature calibration baths engineered for metrological traceability in accredited calibration laboratories, pharmaceutical QC environments, and national metrology institutes. These instruments operate on the principle of forced-convection liquid circulation within a thermally insulated bath chamber, utilizing a high-stability heating system coupled with intelligent ICC (Intelligent Control Circuit) and TCF (Temperature Control Function) algorithms to maintain exceptional thermal homogeneity and temporal stability. Designed specifically for primary and secondary temperature sensor calibration—including PRTs, thermistors, liquid-in-glass thermometers, and digital probes—the SL-series achieves ±0.005 °C short-term stability and < ±0.01 °C spatial uniformity across the working volume, meeting the stringent requirements of ISO/IEC 17025:2017 for calibration uncertainty budgets. The overflow tube design ensures laminar flow distribution and minimizes thermal stratification, while the integrated SmartPump dynamically adjusts impeller torque in response to bath fluid viscosity changes—critical when operating across the full +50 °C to +300 °C range with silicone or mineral oils.

Key Features

• VFD + LCD dual-display interface showing real-time bath temperature, setpoint, and external reference probe reading simultaneously
• ATC3 (Automatic Three-Point Calibration) function enabling in-situ verification and correction against certified reference standards
• Integrated Pt100 input channel for direct connection and closed-loop control of external systems or auxiliary sensors
• RS232 serial interface as standard; optional RS485 or Profibus modules support integration into automated calibration workstations and LIMS environments
• Programmable 6×60-step temperature profiles with ramp/soak logic for automated multi-point calibration sequences
• SmartPump technology automatically modulates circulation pressure (0.4–0.7 bar) and flow rate (22–26 L/min) to compensate for fluid density and viscosity shifts at elevated temperatures
• IP65-rated waterproof keypad with tactile feedback for reliable operation in humid or solvent-exposed lab settings
• Dual-stage overtemperature protection: adjustable knob-set limit + hardware-independent thermal cutoff per DIN 12876-1 Class III (FL)
• Low-level detection circuit triggers visual/audible alarm and halts heating before dry-run conditions occur

Sample Compatibility & Compliance

The SL-8K (8 L capacity) and SL-14K (14 L capacity) accommodate a wide range of sensor geometries via standardized multi-hole stainless-steel bath covers (7-port configuration included). Each port accepts probes up to Ø16 mm, supporting simultaneous calibration of up to seven devices under identical thermal conditions—essential for inter-laboratory comparison studies. Both models comply with DIN 12876-1 Class III (FL) for flammable liquid safety, and their thermal performance is validated per ISO 17025 clause 6.4.3 for equipment suitability in accredited calibration. Optional DKD-accredited reference thermometers (traceable to PTB) and CNAS-certified calibration reports from China’s National Institute of Metrology (NIM) are available upon request. All firmware and control logic adhere to IEC 61508 SIL 2 functional safety principles for critical temperature monitoring applications.

Software & Data Management

While standalone operation requires no software, the RS232 interface enables bidirectional communication with JULABO’s optional LabSoft PC software or third-party SCADA platforms compliant with Modbus RTU protocol. Full audit trail functionality—including timestamped setpoint changes, alarm events, and calibration cycle logs—is supported when paired with validated data acquisition modules (e.g., JULABO’s 8 900 100 series). For regulated industries, the system supports 21 CFR Part 11-compliant electronic signatures and user access levels when deployed with validated GxP software environments. Raw temperature data exports in CSV format facilitate statistical process control (SPC) analysis using Minitab or JMP, and all internal memory retains ≥10,000 data points with time stamps at 1-second resolution.

Applications

• Primary calibration of industrial platinum resistance thermometers (PRTs) and SPRTs in metrology labs
• Verification of thermocouple calibrators and handheld digital thermometers per ASTM E220 and IEC 60584
• Stability testing of temperature-sensitive pharmaceutical formulations during accelerated stability protocols (ICH Q1A)
• Validation of sterilization autoclave temperature mapping systems per ISO 13485 and FDA Guidance for Industry
• Thermal validation of environmental chambers and incubators used in GLP-compliant biological testing
• Research-grade studies requiring ultra-stable thermal environments—for example, polymer melt rheology prep or crystal growth kinetics

FAQ

What is the maximum allowable bath fluid temperature for long-term operation?
Continuous operation at +300 °C is permitted only with high-temperature silicone oil (e.g., Dow Corning 200 Fluid, Grade 50000 cSt); mineral oils must be limited to ≤+200 °C.
Can the SL-series perform cooling below ambient temperature?
No—the SL-8K/SL-14K are heating-only systems; for sub-ambient calibration, consider JULABO’s F26 or PRESTO A80 series with integrated refrigeration.
Is DKD accreditation included with the instrument purchase?
DKD certification applies only to optional reference probes—not the bath unit itself; however, factory calibration certificates traceable to PTB are provided as standard.
How often does the system require maintenance?
No scheduled maintenance is required; periodic visual inspection of bath fluid level and cleanliness every 6 months is recommended for optimal thermal performance.
Does the ATC3 function replace the need for external calibration?
ATC3 improves in-use accuracy by compensating for drift but does not eliminate the requirement for periodic third-party calibration per ISO/IEC 17025.