Neat. This is basically the concept of the traditional chinese corn and rice poppers used by street vendors. The rice or corn is placed in in a round metal device which is rotated rapidly over a fire and then placed in something like a large rubber funnel. A handle through the side of the rubber funnel hooks onto the release mechanism of the cylinder; the vendor kicks the handle, releasing the pressure with a loud bang, and the popped material is collected in the rubber funnel. My wife remembers being fascinated by them as a young girl in China. If you google "traditional chinese rice popper" you should pull up a picture of one.