Application
The Sweating Guarded Hotplate is the world’s most advanced, stable, and professional thermal and evaporative resistance testing instrument. It simulates human skin using a specialized test plate, incorporates an automatic water supply system, and features a wind speed stabilization system. The test host and climate chamber are completely separate in design. The height of the hotplate is automatically adjusted based on the thickness of the test sample, ensuring that the wind sensor is positioned 15mm above the hotplate.
The system includes a Windows-based software that connects via Wi-Fi, allowing operators to control and monitor tests remotely from an office.
An advanced temperature and humidity chamber is also included with the machine.
Testing Method
Why We Need the Thermal Resistance Test
When wearing clothing in different climates, the temperature of the fabric, especially when close-fitting, adjusts according to the temperature of the skin. Selecting suitable clothing ensures comfort and protection in adverse weather conditions. Thermal resistance is key in fabric choice: clothing with higher thermal resistance offers better cold protection, while lower thermal resistance fabric provides a cooling effect. Therefore, testing thermal resistance provides essential insights into improving clothing comfort.
Thermal Resistance Test Principle
Our Sweating Guarded Hotplate employs the constant temperature method. The fabric sample is placed on an electric hot plate, which is insulated on all sides, and heat is transferred to it until it reaches a constant temperature. The heat needed to maintain this temperature is then measured. This method is used as the standard in ASTM D1518.
Sweating Guarded Hotplate Test Method
- Assemble the instrument and install the SGHP software.
- Connect the thermal resistance instrument via the network and prepare for testing.
- Perform the RCT0 test to obtain the basic parameter of the machine. This test is crucial after long periods of inactivity or significant environmental changes.
- Cut a 50cm x 50cm sample and pre-treat it according to the standard. Place the sample on the test surface.
- If the sample thickness exceeds 1mm, adjust the wind speed sensor height to maintain 15mm distance from the sample.
- Set the required temperature and humidity based on standards and start the test until the environment stabilizes.
- Record the results and calculate the final RCT values for the sample.
Daily Maintenance
- Keep the Machine Clean: Use a towel to clean the test plate surface and the exhaust grid.
- Post-Test Maintenance: After the Ret test, if another Ret test will be conducted the next day, open the safety cover and conditioning chamber door to allow the water to evaporate and prolong the machine’s lifespan.
- Long-Term Inactivity: If the conditioning chamber is not in use for an extended period, drain the water from the chamber.
Specification
Standards
ISO 11092, ASTM F1868, ASTM D1518, GB/T 11048, JIS L1096
Power
110V/220V 50 Hz
Weight
600 Kg
Dimensions
1600 x 1300 x 1800mm (L x W x H)
Technical Specifications
- (RCT) Thermal Resistance Range: 0.002 – 2.0 m²K/W
- Repeatability: ≤ ±2%
- Resolution: 0.0001 m²K/W
- (Ret) Evaporative Resistance Range: 0 – 1000 m²Pa/W
- Repeatability: ≤ ±2%
- Resolution: 0.001 m²·Pa/W
- Test Temperature Range: 0 – 35°C
- Temperature Control Accuracy: ±0.2°C
- Air Velocity: 0 – 1 m/s
- Air Velocity Accuracy: ±1%
- Sample Platform Lift Range: 0 – 50 mm (automatic lift)
- Sample Thickness: 0 – 50 mm
- Test Plate Area: 254 mm x 254 mm
- Guard Ring Size: 512 mm x 512 mm
- Guard Ring Width: 127 mm
