Talk:Locally manufactured thermostatic valve for water pasteurization
Since this page hasn't been created ill get it started.... If you find a usefull like post it in here so that we can all look at it.
Hey guys! How perfect, I was just about to make this page so I could post an interesting study I found. For whoever was looking into waxes, you can find it through the library website, it's called "Study on Influence Factors of Thermal Hysteresis in Paraffin Actuator". I turns out that waxes expand a lot when they melt. The study is trying to lessen thermal hysteresis which is when a material's properties differ when they heat over a certain temperature range than when they cool over the same range. It's a study that is absolutely applicable to our project, so feel free to check it out. If we were to use melting wax, we would need to use a spring to push the piston back into position, this study looks at different springs effects on paraffin wax's thermal hysteresis. Anyways, that's all I wanted to post. -Sarah
- I found this book on knovel "Engineering with Rubber - How to Design Rubber Components (2nd edition)" In the appendix it talks about the expansion coefficients of different rubbers. Polyisoprene is natural rubber so i think if we did use a rubber it might be that one. Also that wax stuff sounds promising.
- This web site also lists a bunch of thermal expansion constants in 10-6 m/m K. Rubber has 77 10-6 m/m K. Still dont know at what temperatures though.
- This web site will calculate the linear thermal expansion of something if you know the expansion coefficient. If rubber is 1m at 25C and its heater to 75C then it is 1.004m. Im hoping wax will expand more than that. http://www.engineeringtoolbox.com/linear-thermal-expansion-d_1379.html
I think different paraffin waxes should be one of the materials we test for properties. We could fill a piston with different mixtures of paraffin and see which ones expand the most at the temperatures we want. We could also do tests similar to the ones in the study I posted, with different springs to see which ones return the piston to its original position within an acceptable time and temperature range. -Sarah
Great start -- not a lot of activity from the proposal stage. Make your images thumbnails and start collaborating on your design here so that we can all see how it evolves. Think about ways you can magnify the expansion - dont have the wax do the work directly. --Joshua 20:09, 16 March 2009 (UTC)