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I'm looking for a wireless, relatively small (think a quarter dollar size) temperature sensor capable of withstanding and measuring temperatures up to 600 °C (1100 °F). It is going to be located inside a metal mold, and I don't need to receive the data in real time.

Could anybody point me in the right direction?

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    \$\begingroup\$ It will be tough to get the sensor data through a metal mold wirelessly... \$\endgroup\$ – Eugene Sh. May 28 '18 at 21:22
  • \$\begingroup\$ If an antenna is needed, I can drill a hole for it. Would that be an acceptable solution? \$\endgroup\$ – user190081 May 28 '18 at 21:24
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    \$\begingroup\$ Then you can just put a probe in it and run a wire outside. \$\endgroup\$ – Eugene Sh. May 28 '18 at 21:25
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    \$\begingroup\$ Can't you just infer the temperature of the interior based on the temperature of the exterior and the duration of heating? You could aim an IR (contactless) sensor at the mold. \$\endgroup\$ – Reinderien May 28 '18 at 21:53
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    \$\begingroup\$ Or put a thermocouple right in the mold, drill a hole, run heat-resistant wires away from the heating elements and set up a small transceiver in a relatively safe area. \$\endgroup\$ – Reinderien May 28 '18 at 21:58
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I already have pyrometer in place, but I want to know the temperature distribution inside the mold (I have cooling and heating sections).
[from O.P.'s comment under an earlier answer]

and

I'm looking for a wireless, relatively small (think a quarter dollar size) temperature sensor capable of withstanding and measuring temperatures up to 600 °C (1100 °F).

Let's separate the two problems: measuring high temperature, and electronics working at high temperature.

Thermocouples themselves can survive at 600 °C and make measurements. Thermocouples can be made quite small.

You would need to choose between grounded or floating thermocouples (see also discussion here). Grounded thermocouples have a faster response time. Floating thermocouples can work with simpler signal conditioning circuitry.

You would need to insulate the thermocouple wires from each-other and from the metal mold. So, you will need electrical isolating material which can survive 600 °C. Ceramics and glass can do that.

Thermocouples need signal conditioning circuitry to make measurements. Silicon semiconductors will not survive at 600 °C, as it was already mentioned in a previous answer. You will either need to insulate your electronics, or keep the electronics in a cool place and connect it through long thermocouple wires.

A lot of the arrangement would be defined by the mechanics of your casting process. Is the mold spinning? Is it running through a conveyor? And such questions.

The mold is mounted on a rotating machine, and the temperature outside the mold is higher (it is heated by several burners).
[from O.P.'s comment under the question]

Perhaps you might build a thermally insulated path for the thermocouple wires along the axis of rotation of the machine. (If you post more about your mold and the rotating machinery, we might be able to say something more concrete. Pictures usually help.)

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Electronic components in general won't survive 600C. Currently, the top end is 200~260C, depending on component type, which has been driven in part by the geothermal and the oil and gas industries for downhole instrumentation.

For environments that exceed this limit, one method is to package the electronics in a dewar flask, sometimes along with a mass of eutectic metal. This allows the electronics to be immersed in a high temperature environment for a limited time.

There are companies that specialize in developing custom electronics for hot environments. Do a web search for hi temp electronics.

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    \$\begingroup\$ Thermocouples will definitely survive, but basically nothing else will. \$\endgroup\$ – Reinderien May 28 '18 at 21:59
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If what you are wanting to measure the temperature of is spinning (such as hot turbine blades in an aero engine) then one method is to use a pyrometer to optically measure the surface temperature of the spinning object: -

enter image description here

This keeps the electronics static on the machine and importantly away from hot gases/materials. A pyrometer can be used to detect hot-blades inside an engine: -

enter image description here

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  • \$\begingroup\$ Andy, I already have pyrometer in place, but I want to know the temperature distribution inside the mold (I have cooling and heating sections). \$\endgroup\$ – user190081 May 29 '18 at 12:53

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