So far I have only found polyethylene bags in my area. I called every plastic bag supplier in my area.
Here is a request I sent to a Nylon supplier.
I am working on a prototype Stirling engine, that requires sealed pistons. I am looking for thin plastic film material with high temperature strength, fold crack resistance and low cost.
For my initial testing the working temperature will only be 210 degrees F and am building it out of acrylic plastic. This way it will be easy to keep an eye on the seals and to demonstrate the principles. Your Kenylon products seem like a good fit.
My plan is publish the plans for the engine Open Source using standard sized parts, so others could contribute and to speed the development. I will be making sealed piston/cylinder assemblies available as product, since based on my current experience, getting the plastic material with the correct properties and dimensions has not been easy. Each engine would have at least 4 cylinders, I am expecting that there will be a significant failure rate of the seals, so they may have to be replaced after a short period of time, until we can find the proper balance between thickness, pressure and folding life.
I almost have the prototype engine complete, except for the seals.
Right now I am using polyethylene bags, but they don't maintain their shape very well and begin leaking.
I need a stronger material.
The width is somewhat critical, so the bag fits snuggly around the piston which is 1.95" in diameter. A 3" bag is a little snug but should work. I am considering going to 1.90" diameter, because it is standard size for an aluminum tube, which I will switch to for production. In production I am expecting to have to reshape the bags, to different diameters in each section, to make assembly easier. Once the cylinder is under pressure the bag will stretch to fill the gap. So for now it just takes me more time get it fitted over the larger cylinder OD to make the seal.
I need at least 4 pcs of 3" wide nylon tube bags that have seamless sides and a heat sealed bottom. The length is 6" minimum. If I could get then with different thicknesses that would be great, but 4mil is a good start. getting 2 and 6 mil sample bags would be great.
Subscribe to:
Post Comments (Atom)
2 comments:
I wish you luck! I'm just having a hard time envisioning your 'bag' concept for now. I'm still planning on using Teflon bushings, if I can get to that point. I started tooling up for a similar project about a year ago but it wound up on the back burner for a while. I hope to start cutting metal this summer when I am forced to be indoors from the heat. Like yours, its a planned 4 cylinder sterling, but for a solar concentrator and electric generator in my case. I also need a solar tracker and a lot of power electronics as well. So, You'll probably beat me to the finish line, but I'll still have fun trying to keep up. ;) < scoleman (a.t) patriot .dot. net >
As far a bearing go, I have seen high density polyethylene ones at Grainger Industrial Supply.
If you read my recent post, my design should be scalable, sets of 4 cylinder sections can be stacked to any size. The drive shaft is just a straight rod all the way through.
Good luck on your project. We can use all the energy we can get, until hydrogen-boron fusion gets online.
Post a Comment