High-temperature calibration bath Hydra 798

low-temperaturefor temperature sensorshigh-precision

Summary
The Hydra series calibration baths deliver very high stability (0.01°C) and excellent homogeneity for precision temperature sensor calibration.

Main features

• Deep stirred calibration bath with 300 mm immersion depth
• Three models covering ranges from -80°C to 300°C
• Typical stability: 0.01°C
• Superior uniformity provided by parallel-tube technology

Detailed description
The Hydra stirred calibration bath provides exceptional stability (0.01°C) and uniformity, designed for calibrating precision temperature probes in laboratory and industrial metrology applications. The 300 mm immersion depth complies with BIPM recommendations (approx.15–20 cm for -50°C to 50°C; 200–270 mm immersion for high temperatures). The parallel-tube bath technology ensures superior uniformity: the cylindrical calibration volume requires only 5 litres of fluid (water, alcohol or oil depending on temperature). Models Hydra L and M can be connected to an external cooling source to reduce cool-down time. The parallel-tube flow circulates fluid behind the calibration zone and through the working area, minimizing vertical and axial gradients and thus reducing measurement uncertainty.

Graphs
Temperature rise/fall curves and calibration volume graphs are available in the product datasheet.

Specification table (key)
Model | 798L | 798M | 798H
Temperature range | -80°C to 125°C | -40°C to 125°C | 30°C to 300°C
Volume | Diameter: 150 mm
Depth: 300 mm (5 litres)
Absolute stability | ±0.003°C (Methanol, @-80°C) | ±0.017°C (Methanol, @-40°C) | ±0.015°C (C10 Oil, @125°C)
Vertical uniformity | 0.002°C (oil, @50°C) | 0.002°C (oil, @50°C) | 0.005°C (oil, @200°C)
Heating time | 25°C to 200°C: < 60 min (C10 oil)
Cooling time | 0°C to 80°C: < 130 min (Methanol)

General specifications
Dimensions L x W x H: 405 x 610 x 540 mm
Mass | 59 kg (798L) | 46 kg (798M) | 33 kg (798H)
Power supply | 110 V or 130 V (50/60 Hz)
Power consumption | 2.5 kW (798L) | 1.5 kW (798M) | 800 W (798H)

Accessories and options

• Cover (ref. 798-05-01)
• Aluminium equalizing block (798-05-02) or copper (798-05-02B)
• Support for two fixed-point cells (798-05-03)
• Probe support (798-05-04)
• Probe calibration support kit (796-05-03)
• Recommended silicone oils and fluids (refs 915/07, 915/08, 915/09, ACL5012-01/936-06-07, 580-06-09)

Technical characteristics / specifications

• Commercial model: Hydra 798
• Immersion depth of calibration zone: 300 mm
• Cylindrical calibration volume: 5 litres
• Calibration zone diameter: 150 mm
• Available ranges: -80°C to 125°C (798L), -40°C to 125°C (798M), 30°C to 300°C (798H), EHT version 30°C–300°C
• Stability and uniformity depend on model and fluid (see table above)
• Rise/fall times depend on fluid (e.g. 25°C→200°C <60 min with C10 oil)
• Power supply: 110 V or 130 V (50/60 Hz)
• Mass and power by model (see table above)