High-temperature calibration bath 6331

low-temperatureultra-low-temperaturefor temperature sensors

Product overview
Fluke Calibration Deep‑Well Compact Baths model series 6331, 7341 and 7381 are laboratory temperature baths designed for precise calibration of long‑stem probes (PRTs, SPRTs) and liquid‑in‑glass (LIG) thermometers. Each unit features an 457 mm (18 in) deep tank with a 120 x 172 mm access opening and an operational fluid volume of approximately 15.9 L, enabling simultaneous calibration of multiple sensors while minimizing fluid usage.

Key features

• Three models covering temperature ranges from −80 °C to 300 °C (model dependent).
• High temperature stability and uniformity (stability as low as ±0.005 °C; uniformity as low as ±0.007 °C at specified points).
• 457 mm immersion depth with only 15.9 L fluid required; optional LIG kit increases usable depth to 482 mm.
• Digital temperature controller with high‑resolution setpoint and automatic refrigeration control.

Models

• 6331 — Deep‑Well Compact Bath, 35 °C to 300 °C.
• 7341 — Deep‑Well Compact Bath, −45 °C to 150 °C.
• 7381 — Deep‑Well Compact Bath, −80 °C to 110 °C.

LIG kit and accessories (optional)
The optional Liquid‑in‑Glass (LIG) calibration kit includes a fluid‑level adapter tube, a carousel for up to 10 LIG thermometers and a front‑mounted magnifier (8X) for meniscus observation. An overflow reservoir captures excess fluid for reuse and a drain facilitates emptying.

Performance and control
The Fluke Calibration controller manages heating and refrigeration automatically, adding cooling when required and disabling refrigeration for rapid heating. For maximum stability, refrigeration levels are balanced to the setpoint. Typical stabilization time is 15–20 minutes; heating and cooling times vary by model (see specifications).

Automation & connectivity
Units can be integrated with Fluke Calibration readouts and MET/TEMP II software for automated probe calibrations. Automation of multi‑sensor calibrations is supported using the 1586A Super‑DAQ or comparable interfaces.

Documentation & handling
Each unit is supplied with a test report including one hour of stability data and verification of setpoint accuracy. Wetted parts are stainless steel 304. Electrical configuration and power ratings depend on model and region; specify required voltage when ordering.

Technical specifications (selected)

• Range: 6331: 35 °C to 300 °C; 7341: −45 °C to 150 °C; 7381: −80 °C to 110 °C.
• Stability examples: 6331: ±0.007 °C at 100 °C (oil 5012); 7341: ±0.005 °C at −45 °C (ethanol); 7381: ±0.005–±0.006 °C at specified points.
• Uniformity examples: 6331: ±0.007 °C at 100 °C; 7341/7381: ±0.007 °C at many reference points.
• Immersion depth: 457 mm (482 mm with LIG kit).
• Access opening: 120 x 172 mm.
• Fluid volume: ~15.9 L.
• Setpoint resolution: 0.01° (0.00018° high‑resolution mode); display resolution 0.01°.
• Typical stabilization time: 15–20 minutes.
• Dimensions (HxWxD): 1067 x 356 x 788 mm (tank access 940 mm from floor).
• Weights: 6331: 41 kg; 7341: 68 kg; 7381: 91 kg.
• Automation: compatible with 1586A Super‑DAQ and MET/TEMP II software.