High-temperature calibration bath Libra 785

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Overview
The Libra 785 stirred liquid calibration bath with a parallel-tube design delivers very high stability (< 1 mK), excellent uniformity and a deep calibration cavity. Models cover temperature ranges from -80°C to 300°C with very low uncertainties (< 1 mK). The design inherits key features from the Neptune 915 generation, providing an economical solution while maintaining physical separation between the heating/cooling zone and the work area.

Key points

• Physical separation between heating/cooling and the work area
• Three models covering -80°C to 300°C (785L / 785M / 785H)
• Excellent uniformity and uncertainties below 1 mK
• Integrated cooling system to reach the lowest temperatures
• Deep calibration cavity (485 mm) while requiring only 8.5 L of fluid

Operation

• Fluid descends into the mixing chamber through a plate with an adjustable flow orifice; flow is set from the control panel.
• The heating/cooling section is cylindrical to ensure optimal flow and uniformity.
• The calibration cavity is separated from the heating/cooling area by parallel tubes.
• The fluid slightly overflows above the bath cover, enabling full immersion of expansion thermometers.
• Fluid circulates through a large expansion area during heating before returning to the bath circuit.
• High-performance thermal insulation.

Delivered as standard

• Cal Notepad software
• Serial communication cable
• User manual

Fluids / oil notes
The bath requires 8.5 L of fluid to fill the cavity. Recommended fluids depend on the temperature range (examples: C10 oil, VH oil, methanol). Specific fluid recommendations are given per model and temperature range.

Technical specifications

• Available models: 785L, 785M, 785H
• Temperature ranges: 785L = -80°C to 125°C; 785M = -40°C to 125°C; 785H = 30°C to 300°C
• Calibration cavity: diameter 98 mm; depth 485 mm (8.5 L)
• Absolute stability: ±0.0025°C (water @ 50°C); ±0.006°C (methanol @ -80°C for 785L, methanol @ -40°C for 785M, C10 oil @ 125°C for 785H)
• Vertical uniformity: < 1 mK
• Heating time: 25°C to 125°C < 50 min (C10 oil); 30°C to 250°C < 150 min (VH oil)
• Cooling time: 0°C to -80°C < 300 min (methanol); 10°C to -40°C < 180 min (methanol)
• Display resolution: 0.01°C
• Liquid height above surface: 3 mm
• Design: parallel tubes (calibration chamber and liquid mixing chamber)
• Dimensions (H x W x D): 485 x 525 x 1150 mm
• Mass: Model L = 78 kg; Model M = 68 kg; Model H = 48 kg
• Power supply: 108 / 130 V or 208 / 240 V, 50/60 Hz
• Power: 785L = 2.8 kW; 785M = 1 kW; 785H = 800 W
• Available accessories: aluminium equalization block (915/01a), copper equalization block (915/01b), glass thermometer holder (915/02), monocular and holder (915/03), calibration tube and equalization block holder (915/05), probe calibration support kit (796-05-03)
• Compatible oils (examples): silicone oil 40°C–180°C (915/07), silicone oil 150°C–250°C (915/08), silicone oil 40°C–288°C (915/09)