Cooling system for MOV(motor operated valve)

[nukude]

Dear members,

Hello, I am looking for the solution against hot environments.

The electrical circuit board inserted in MOV has been damaged from hot environments in thermal power plant. Especially the MOV near HRSG can be exposed on extremely high temperature, 65 Celsius.

I was told that one option is using vortex tube method, but new instrument air line is not available at this moment. Another is to change circuit board to stand high temperature. But this is not suitable for me.

I'd higly appreciate it if you could provide me with good advice.

Best regards,
nukude

 

[ScottyUK]

65°C isn't all that hot in terms of electronics. With appropriate choice of components - and specifically capacitors - you should be able to operate well above that temperature.

Why can you not increase the distance between the actuator and the heat source, e.g. use an extended spindle valve? If you have ruled out venturi coolers then you could possibly use a Peltier cooler within the actuator head, or a water-jacket cooler on the actuator body. Both have downsides.

 

[nukude]

Thanks ScottyUK,
I agree 65°C is not high temperature, but the the life time of electronic euqipment could be decreased if it is exposed to hot environment during long time. Anyway, a Peltier cooler is very interesting idea. Have you ever seen or used a Peltier cooler for this kind of application?

 

[LittleInch]

What sort of heat is it getting?

Radiation or ambient air / metal conduction?

Stopping the heat flow is your first point of call - a heat shield can effect temperature reduction of 10+ deg C if the ambient air is low enough.

what does the vendor say? Can you retrofit cooling fans?



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[nukude]

The type of heat is ambient air.
My vendor wants the internal cooling system rather than a heat shield. But the internal cooling system for valve actuator is very challenging issue, and I have never experiences. With external cooling by fan, I think the effiency would be low than internal cooling. If there is a chance to use a peltier cooler within the actuator head, it would be best choice i think.

 

[gerhardl]

I can hardly believe that 65 deg C ambient temperature is the single problem here. A normal, solid and correctly component selected board should withstand this, as commented above. What about shattering and external/internal other heat resources, and (systematic?) fabrication fault of one or several components or the board itself?

As the board has been damaged it must have been changed or repaired. What is the reason that it cannot be checked and strengthened at this point?

The cheapest cooling solution I can think of is a (flexible) tube fetching air from a cooler point and forcefed by a small fan, redundant (two separate fans) if very critical.

 

[LittleInch]

"but new instrument air line is not available at this moment"

So what is available?
electrical power? ( volts, amps)
water?

Also remember that anything cooler than ambient could generate condensation.

for the peltier coolers, you still need to remove the heat via your 65C ambient air. Hence the cooling effect could be quite low (20C?) Is that enough?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[nukude]

Sorry for late response. I had a long business trip.
My client has decided to apply peltier cooler because electrical power(220V) is available.
But exact and detail method are not completed yet. Target temperature is 45 Celsius.
I will post again if we have a good results.
Thank you for your help.