వివరాలు

The Transient Hot-Wire (THW-L1) Liquid Thermal Conductivity Meter is an advanced measurement system, compliant with ASTM D7896-19, designed for the primary, accurate, and rapid measurement of thermal conductivity, thermal diffusivity, and specific heat in small volumes of liquids, pastes, powders, and PCMs. This instrument prioritizes speed and operational simplicity, achieving a full measurement in just 1 second using a non-stationary approach with rapid test times to effectively limit convective effects across a wide range of sample viscosities. Its core is a 40 mm thin heating wire sensor, which, once fully inserted into the sample, is heated by a constant current source (q); the resulting temperature rise is then tracked by monitoring the change in the wire's electrical resistance. Finally, the thermal conductivity (l) is calculated based on the slope (m) derived from the plot of temperature rise versus the logarithm of time, where a lower slope signifies higher thermal conductivity, and a higher slope indicates lower thermal conductivity.

 

Model and Make

 Thermtest THW-L1, Thermtest Instrument, Canada

Specifications

Key Features:

  • Measurement Capabilities: Thermal conductivity (0.01 to 2 W/m·K), thermal diffusivity, and specific heat
  • Sample Volume: Approximately 20 mL
  • Measurement Time: 1 second
  • Viscosity Range: 0.001 to 10,000,000 cP
  • Accuracy: ±2% for thermal conductivity
  • Repeatability: ±1%
  • Temperature Range: THW-L1: -40°C to 300°C
  • Pressure Capability: Up to 35 bar, enabling measurements above boiling points
  • Standard Compliance: ASTM D7896-19
  • Cooling Options: External circulators available for sub-ambient testing

Applications

  • Liquids: Water, ethylene glycol, isopropanol, heptane
  • Pastes and PCMs: Coconut oil, chocolate chips, paraffin wax
  • Automotive Fluids: Fresh and used engine oils, transmission fluids
  • Powders: Various materials requiring thermal property analysis