Skin RTD

This is one type of thermocouple used to measure surface temperature of a body.

It's also an excellent phrase for entry into an internet search engine.

I just can't ignore it.

A skin RTD is not a thermocouple, it is a RTD hence the term.

You are correct in saying it is for measuring temperature on the skin.

An RTD attached to the outside of a pipe or vessel not inserted into a thermowell.

A crude method but can be very quickly installed without a system outage.

Kindly give details (manufacturer, type etc.) of any branded skin RTD, THAT YOU HAVE USED/SEEN, for info. of all. I have not, honestly, seen or heard of any skin RTD. To my knowledge: "Typical skin thermocouple assembly comprises of thermocouple, welding pad and strap, intermediate loop (twice pipe diameter), adjustable threaded adapter and heavy duty enclosure etc."

Just to clarify a point no-one has mentioned [because the posters are so familiar with it], RTD means (electrical) Resistance Temperature Detector to an instrument engineer.

It might mean something else, say Arnold Swartzenegger suddenly appearing in nothing but skin in the film "Terminator" - skin Robotic Terminator Delivery = skin RTD.

Joking aside, sometimes, when testing prototype turbines, a skin temperature is got by welding a wire of different metal to the skin and calibrating samples of the wire and skin as a thermocouple [in a furnace] against a standard temperature sensor. Test wires are then welded onto the test prototype skin, using materials from the same wire and skin batches (ingots) as calibrated. The "skin to wire" thermocouple voltage is then logged during the prototype test.

If the skin material has a reliable resistance versus temperature change, one could weld current injection and potential pickup wires onto a skin or product sample and calibrate in an oven as an RTD. Copper comes to mind as reliable material for RTD (short term).

But maybe your description just means a standard RTD is brazed onto the skin to measure its temperature.

Anyhow, with this background, ask the person or organization who used the term what exactly they mean by it. I would!

It is a sensor/probe for surface temperature measurement. Usually it is flat to stick with possibly big area to measuring object. Can be used for example to measure human/animal skin temperature.

Inside it has resistor, whose resistance depends on temperature. Measuring resistance, from Temperature =function(Resistance) calibrated curve You can read/calculate temperature. At -50..150'C..[300'C] Thermistors can be used as sensing resistors. For wider temperature range (-200'C ... +650'C) Platinum Resistors can be used as sensing resistors.

Thermistors are more sensitive but more nonlinear (R(T) curve) than Platinum Resistors.