Using a bimetallic coil to turn a pulley

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Discussion Overview

The discussion revolves around the feasibility of using a bimetallic coil to actuate a pulley mechanism. Participants explore the calculation of the thermal "spring constant" of the coil and its potential applications in heavier work compared to traditional uses, such as in thermometers.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about calculating the thermal "spring constant" of a bimetallic coil based on its geometry and material properties.
  • Another participant questions the concept of using a bimetallic coil in a pulley system, comparing it to a metal tape measure.
  • A participant seeks to understand how to calculate the angle of revolution of the pulley as a function of the temperature gradient.
  • There is a reference to existing devices that utilize similar actuation mechanisms, specifically bimetal thermometers.
  • One participant expresses skepticism about the term "spin" in relation to the pulley, suggesting a need for clarity in terminology.
  • Another participant mentions factors such as the number of turns in the coil and the size of the counterweight as potentially relevant to the mechanism's functionality.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the viability of using a bimetallic coil for this application, and multiple competing views remain regarding its effectiveness and the terminology used.

Contextual Notes

Limitations include the lack of specific calculations for the thermal "spring constant" and the dependence on the definitions of terms like "spin" and "rotate." The discussion does not resolve the practical application of the bimetallic coil in this context.

ENgez
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Hello,

I am looking at the possibility of turning a pulley using a bimetallic coil embedded inside.

How can I calculate the thermal "spring constant" of the coil, as a function of geometry and material properties?

Does anyone know of devices with similar actuation mechanisms?

thank you.
 
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ENgez said:
pulley using a bimetallic coil embedded inside.
... and, working against what? Sounds like a metal tape measure, but I can't describe that as a "pulley."
 
I attached an illustration to further clarify.

Will this work? If so, How can i calculate the angle of revolution as a function of temperature gradient?
 

Attachments

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ENgez said:
similar actuation mechanisms?
http://www.coleparmer.com/Brand/Buy_More_Save_More_on_Bimetal_Thermometers/2262?referred_id=20965&gclid=CNvZ9anWx8cCFUGUfgodiFwCdA
 
Thank you for the reply.

I am aware that bimetallic coils are used to drive the needle in a thermometer.

What I am asking is if this concept can be used to do heavier work, like spin a pulley (wheel), and If there are examples of such mechanisms.
 
ENgez said:
like spin a pulley (wheel),
I keep tripping mentally over the word "spin." You say "spin," and I will think "rotate," and we'll proceed. "Carburetor stoves" are controlled by exhaust manifold dampers https://www.google.com/?gws_rd=ssl#q=exhaust+manifold+damper&tbm=shop
Number of turns in coil, plus size of counterweight, plus 90 degree rotation --- enough to go on?
 

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