When insulating electrical wires in temperature-critical applications Kapton is one of the first choice materials. It can be easily incorporated into traditional wiring designs where single or multi-strand conductors – usually copper – are enclosed within a protective insulating sheath.
In this instance, the insulator is a patented polyimide with links to aeronautics and space exploration, demonstrating extraordinary thermodynamic stability in combination with superior dielectric performance in vacuum conditions.
At Allectra, Kapton-insulated wires are developed in a diverse range of configurations and formats. Besides conventional types for traditional signal transmission, Allectra can provide coaxial cables and flexible ribbon harnesses for the low-loss signal transmission in high-vacuum and ultra-high vacuum (HV/UHV) environments. Allectra’s precision-based Kapton-insulated wire products also accommodate a selection of Kapton thermocouples for temperature-critical vacuum processes.
What are Thermocouples?
A thermocouple is a type of temperature sensor based on a cable made up of two different metallic conductors, which are fused together at one end to create a junction. This junction is exposed to the sensing environment. Thereafter, readings from inside the chamber are transmitted to an external indicator via a hermetically-sealed feedthrough; this allows for continuous, real-time monitoring of in-vacuum temperatures.
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Thermocouples do not directly read temperature. Instead, they calculate process temperatures as a function of charge separation, or electromotive force (EMF) via state-of-the-art software; this is largely dependent upon material combinations. Type K thermocouples are composed of Chromel (90% nickel and 10% chromium alloy) and Alumel (95% nickel, 2% aluminum, 2% manganese and 1% silicon alloy) wires and are among the most commonplace of thermocouple wire pairs.
Type K and Type N Kapton Thermocouples
The alumel-chromel (type K) pairing is widely accepted for various reasons: it is reliable and accurate across a wide range of temperatures and is comparatively inexpensive. Subsequently, type K thermocouples are utilized in a choice of harsh working environments, allowing temperature measurements from -200 °C up to +1250 °C.
Type K thermocouples are well-suited to an array of feedthroughs and measuring instruments, with excellent performance across a large temperature range, they are optimal for temperature sensing in various sectors ranging from research in alternative energy solutions to pioneering surface science.
Type N thermocouple wires provide great stability over time with temperature range measurements from -250 °C up to 1300 °C max.
Allectra supplies Kapton-insulated Type K & N thermocouples for temperature-critical vacuum processing. Note, that Kapton can resist and endure a maximum temperature of +300 °C. Allectra now offers new 301-Type K & N Kapton-insulated thermocouple wires that are UHV compatible as well as radiation hard/resistant.
Kapton is a registered trademark of DuPont.
This information has been sourced, reviewed and adapted from materials provided by Allectra Limited.
For more information on this source, please visit Allectra Limited.