STAvesta/HUM-Auto

High-concentration water vapor atmosphere STA (TG-DSC)

A thermal analysis system for easy TG-DSC measurements in a water vapor atmosphere

STAvesta/HUM-Auto combines a thermogravimetric-differential scanning calorimeter with a water vapor generation system to perform TG-DSC measurements in a controlled water vapor atmosphere. By connecting to HUM-Auto, which allows switching between relative humidity control and dew point control, the system automatically controls each temperature according to the set humidity and also supports humidity control synchronized with the temperature program.

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STAvesta/HUM-Auto Overview

For details on the basic performance of STAvesta, please refer to the main STAvesta page.

STAvesta/HUM-Auto is a system that enables TG-DSC measurements under humidity-controlled conditions by connecting a water vapor generation unit to the STA. Its indirectly heated electric furnace designed for the introduction of water vapor and temperature-controlled structure help suppress condensation while creating a stable humidity atmosphere. This makes it possible to evaluate the effects of humidity conditions on sample mass changes and thermal behavior.

HUM-Auto automatically controls the water bath temperature, transfer tube temperature, and circulator temperature according to the set humidity. Users can switch between relative humidity control and dew point control, and the system also supports humidity control synchronized with the temperature program. Because it can be connected to a gas cylinder or similar supply without requiring special utilities, it is easy to introduce into existing measurement environments.

By connecting an automatic sample changer, the system also supports continuous measurements, helping improve measurement efficiency under humidity-controlled conditions.

Like other STA models, the furnace unit is interchangeable with six different types of furnaces, offering wide applicability for various measurement needs.

STAvesta/HUM-Auto Features

Supports TG-DSC measurements in a water vapor atmosphere

TG-DSC measurements can be performed in a water vapor atmosphere of up to 80°C and 90%RH. While controlling humidity conditions, the system can evaluate humidity-related sample mass changes and thermal behavior, including moisture absorption, dehydration, hydrolysis, and thermal decomposition in humid atmospheres.

Stable humidity atmosphere with reduced condensation

The system uses an indirectly heated electric furnace designed for water vapor introduction. By maintaining the furnace and transfer section at controlled temperatures, condensation inside the furnace and tubing is suppressed. This helps maintain a stable water-vapor atmosphere even in high-humidity conditions, and supports highly reproducible measurements.

Automatic humidity condition control with HUM-Auto

HUM-Auto automatically controls the water bath temperature, transfer tube temperature, and circulator temperature according to the target humidity. Simply setting the relative humidity or dew point in the software enables the system to reach the desired humidity condition, reducing the need to individually adjust complex temperature settings.

Humidity display and control suited to the measurement purpose

Users can switch between relative humidity control and dew point control, selecting the appropriate display and control method according to the measurement purpose and sample characteristics. Water vapor concentration can also be set from the measurement and analysis software in synchronization with the temperature program.

Easy installation and support for a wide range of measurements

The system can be connected to an available gas cylinder or similar supply without requiring special equipment such as a compressor. Efficient operation is supported by functions such as introduced gas flow control and the MFC OFF temperature function. It also supports furnace exchange according to the measurement purpose and continuous measurements using an automatic sample changer.

STAvesta/HUM-Auto Specifications

Model name	Thermo plus EVO3 STAvesta/HUM-Auto
Instrument name	High-concentration water vapor atmosphere thermogravimetric-differential scanning calorimeter
Balance type	Horizontal differential thermobalance (TG-DSC)
Measurement temperature range	Room temperature to 1400°C
Heating rate (max)	20°C/min
Sample amount (max)	1 g (90 μL)
TG range	± 500 mg
DSC range	± 600 mW (100°C) ± 1400 mW (1000°C)
DTA range	± 1000 μV
Humidity control range	Room temperature to 80°C, 5 to 90%RH
Wet gas flow rate	200 to 600 mL/min
Transfer tube temperature	Max. 110°C
Water bath temperature	Room temperature to 90°C
Dry gas flow rate	HUM-Auto: 200 to 500 mL/min Balance purge gas: 150 mL/min
Stabilization time after humidity change	Within 10 min (10%RH)
Continuous operation time	60°C 90 %RH, more than 100 hrs 80°C 90 %RH, more than 40 hrs
Variable humidity system	Feedback type humidity control system
Temperature and humidity sensor	Humidity sensor: Polymer-type relative humidity sensor Temperature sensor: Platinum resistance thermometer Calibration accuracy (humidity): ±1.5 %RH (10 to 95 %RH at 25°C) Calibration accuracy (temperature): ±0.3°C
Mass flow controller (built-in)	One unit each for dry gas and wet gas (water bath bubbling gas)
Controlled humidity system	PID control
Humidity stability	± 2 %RH after reaching the set value
Gas type	Dry N₂ gas
Bubbler volume	300 mL
Measurement atmosphere	Humid atmosphere
Options	Automatic sampler changer (samples: 52, references: 3, calibration samples: 5)
Dimensions	STAvesta 　412(W) x 355(H) x 621(D) mm 　412(W) x 705(H) x 621(D) mm with ASC HUM-Auto 　200(W) x 250(H) x 420(D) mm
Mass	STAvesta 　50 kg 　66 kg (with ASC and safety cover) HUM-Auto 　7 kg
Power requirements	STAvesta 　1Ø, AC100-120V/200-240V, 50/60Hz, 15A HUM-Auto 　1Ø, AC100-120V/200-240V, 50/60Hz, 6A