Paraffin Wax Actuator Design guide???

[quizzical1]

Hi All,

Does anyone know of a good reference book on designing these type of thermal actuators?
I know S. Vernet from his early patents showed examples back in the 1930's - 1950's but was wondering if anyone ever came across a design guide.

TIA

~Q

 

[GregLocock]

Yes, they are used for things like greenhouse windows, and the manufacturers have design guides.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[3DDave]

They are pretty simple - you need to determine the volumetric expansion of wax for the temperature required and figure out how much pressure the external load of actuation will be produced plus the load of the return spring. Other than that it's just a small hydraulic device that has a solid-liquid transition for the working fluid.

https://www.youtube.com/watch?v=B1SScrdAq3g

 

[quizzical1]

Thanks guys, I appreciate your help

 

[btrueblood]

The Vernet company still exists, you can google for them. They have a pretty decent engineering department that can help you out.

FWIW...an electric motor actuator will usually be more efficient than a wax actuator if you are operating at near room temperature (i.e. you apply electrical heating to make the motion you want). Reason being that the motor can move to a position and hold it (with suitable non-slip gearing), but the wax pellet requires constant thermal input to hold a position other than its "cold" position. Places where wax motors work well is in thermal regulation, where operating temperatures are within melting range of wax/oil mixtures.

 

[quizzical1]

Thanks btb!