HOT DISK Thermal Conductivity Measurement Sensors

Sensors

hotdisk sensors

The Hot Disk sensor, at its core, is an insulated nickel double spiral, which is utilized for both transient heating and precise temperature readings. The insulation material makes the sensor mechanically stable and very durable, and the use of nickel metal in the spiral makes the thermal conductivity measurements very accurate. To accommodate different material types and sample geometries, sensors with radii from 0.5 mm up to 30 mm are available. Furthermore the sensors’ insulation material can be Kapton (polyimide), mica (sheet silicate minerals) or Teflon (polytetrafluoroethylene - PTFE) to tackle different temperature ranges and/or extreme conditions.

hotdisk kapton

Kapton Sensors

The Kapton-insulated sensors are the most versatile in the Hot Disk sensor portfolio. They have a very long lifetime, if handled with care, even when employed at temperatures as high as 300 °C in air. To ensure functionality the sensor should not be ripped or folded. The sensor should also be kept in its protective sheet when not in use.

Kapton sensors for Isotropic, Anisotropic, Slab, One-dimensional and Structural Probe measurements, operating temperature from -196 °C up to 300 °C (400 °C in vacuum):

 

Sensor design: Radius (mm):
7531 * 0.5
7577 * 2.0
7577Q */** 2.0 with extended Kapton
5465 3.2
5465Q ** 3.2 with extended Kapton
5501 6.4
5501Q ** 6.4 with extended Kapton
8563 9.9
4922 14.6
4922L *** 14.6 with extended leads
5599 29.5
5599L *** 29.5 with extended leads

 

* Not for anisotropic measurements.

** For special applications and easier suspension in liquids or melts.

*** Intended for large and very high-conducting samples.

Kapton sensors for thin film measurements, operating temperature from -196 °C up to 300 °C (400 °C in vacuum):

 

Sensor design: Radius (mm):
7854 10.5
7280 14.7
7281 30.0

 

Also available: Specific heat capacity sensor equipped with gold cell sample holder. Ships with low density foam insulation, for use at maximum 150 °C. Maximum sample size in the gold cell: 19 mm diameter and 5 mm thickness.

All Kapton-insulated sensors can be acquired with or without attached cables. Standard cables can be used up to 50 °C while high temperature silicone cables are available for temperatures up to 180 °C. Sensors without cable can be mounted in dedicated sensor holders for use up to 300 °C (400 °C in vacuum or inert atmosphere).

hotdisk mica

Mica Sensors

The mica-insulated sensors are designed for measurements at elevated temperatures, typically above 300 °C and up to a maximum of 1000 °C. Due to the strain exerted on the sensors under these circumstances, the lifetime of mica-insulated sensors is limited and they should be considered disposable.

Sensors for Isotropic, Anisotropic, Slab and One-dimensional measurements, operating temperature from 300 °C up to 1000 °C:

 

Sensor design: Radius (mm):
5465 * 3.2
5082 6.6
4921 9.7
4922 14.6
4922L ** 14.6 with extended leads
5599 29.5
5599L ** 29.5 with extended leads

 

* For applications with thermal conductivity larger than 5 W/(mK), the Cp-value must be known beforehand.

** Intended for large and very high-conducting samples.

The mica-insulated sensors are delivered without cables and the sensors are instead mounted in special sensor holders to which electrical leads are attached.

hotdisk teflon

Teflon Sensors

Teflon-insulated sensors are designed for use in extreme conditions, such as acidic or corroding environments, or with sticky and reactivate samples. These sensors otherwise have features similar to the Kapton sensors.

Teflon sensors for Isotropic, Anisotropic, Slab, One-dimensional and Structural Probe measurements, operating temperature from -196 °C up to 250 °C:

 

Sensor design: Radius (mm):
7577 * 2.0
5465 3.2
5501 6.4

 

* Not for anisotropic measurements.

The Teflon-insulated sensors can be acquired with or without attached cables. Standard cables can be used up to 50 °C, while high-temperature silicone cables are available for temperatures up to 180 °C. Sensors without cable can be mounted in dedicated sensor holders for use up to 250 °C.

Cables

LEMO-cables are often attached to the Kapton and Teflon Hot Disk sensors, allowing rapid and trouble-free interfacing with the TPS units. Cables for ambient, elevated and cryogenic temperatures are available. The standard cables can be used under ambient conditions up to 50 °C, the red silicone cables are designed for use at temperatures up to 180 °C, while thin silicon insulated cables (not shown) are used for the lowest temperature ranges.

For sensors without attached cables several different sensor holders, made from e.g. PEEK, Macor or Al2O3, are offered in combination with cables insulated with glass fibers or ceramic beads, all to suit the application and temperature range in question.

cableWithSensor

Kapton Sensor with standard 50°C cable.

greyIsolationCord

LEMO Connector (for Standard Cable)

redCableWithSensor

Kapton Sensor with silicone cable, for use in temperatures up to 180°C.

redCable2

LEMO-FP Connector (for Silicone Cable).

extensionCordAndRedCord

Kapton Sensor with Silicone 180°C cable, connected to LEMO-to-LEMO-FP Adaptor Cable.

extensionCableConnection

2 m LEMO-to-LEMO extension cable (for use with Standard Cable).

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