Pepperl+Fuchs Blog

6 Industrial Sensors for High-Temperature Applications

Posted by Zach Steck on Tue, Sep 17, 2013

Many industrial applications require a sensor that can withstand exposure to high temperatures without becoming damaged. We offer a variety of sensing options for harsh environment installations. In this post, we will take a look at the different industrial sensor options available for high-temperature applications.

Industrial Sensors for High Temperatures

Extended temperature inductive proximity sensors

A standard inductive proximity sensor is generally rated up to 70 ºC, but this rating may not be high enough for many industrial applications. This is why extended temperature models were developed for use in environments reaching temperatures up to 100 ºC. Extended temperature range sensors are identified with a T at the end of their model number.

NCN25-F35… Series

We also have a special inductive proximity sensor for extreme temperatures. The NCN25-F35… Series is usable in temperatures reaching 250 ºC. This sensor is unique because the control interface circuits (amplifier) are separated from the coil system (sensing head). The amplifier is a tubular stainless steel housing that must be mounted in the lower temperature zone, while the sensor head is a polytetrafluorethylene (PTFE) housing which is mounted in the high-temperature area. The two sensor components are connected by a PTFE insulated cable which you can order in lengths of 10 meters, 15 meters, or 25 meters.

NAMUR inductive sensors and NAMUR extended temperature

NAMUR output sensors are designed for use in explosion proof applications. A standard NAMUR inductive sensor is rated for temperatures up to 100 ºC. Extended temperature models are also available. An extended temperature NAMUR sensor is rated up to 150 ºC. This rating is achieved by replacing the standard housing material, PTB (Crastin), with temperature-resistant PPS (Ryton). Ryton remains stable up to 200 ºC, making it an ideal choice for high-temperature installations.

Mobile equipment inductive sensors

Inductive sensors designed for mobile equipment applications feature a slightly higher temperature range than a standard inductive. These sensors have a temperature rating of -40 ºC to +85 ºC, since they need to be able to withstand the demanding conditions experienced by service vehicles.

You may notice that all of the options so far have been inductive proximity sensors. What about applications that need a different type of sensor? Let’s take a look at a couple of options from the other sensor families.

Ultrasonic sensors

The temperature ratings of ultrasonic sensors vary by the model, so you will have to refer to the data sheet when selecting a product from this group. You will see a wide range of options from the flat pack housings rated to 50 ºC, the double-sheet detectors at 60 ºC, all the way up to the stainless steel transducer models rated to 80 ºC. In the ultrasonic group, 80 ºC is the highest temperature offered.

Photoelectric sensors

When selecting a photoelectric sensor for use in a high-temperature application, the best option would be fiber optic cables paired with a fiber optic amplifier. The amplifier housing must be mounted outside of the high-temperature area, since the majority of these amplifiers are rated only to 55 ºC. There are a few different options available for fiber optic cables that are capable of withstanding such extreme heat.

  • Glass cable with PVC sheathing - Usable in temperatures up to 120 ºC
  • Glass cable with stainless steel sheathing - Usable in temperatures up to 232 ºC
  • Glass cable for high temperature - Usable in temperatures up to 482 ºC

These fiber optic cables are offered in both diffuse and thru-beam operation, providing further flexibility for high-temperature installations.

Questions about Industrial Sensors?  Get the Quick Select Product Guide

Topics: Inductive Sensors, Applications, Ultrasonic Sensors, Photoelectric Sensors

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