How much air pressure does old-fashioned popcorn usually need to be crushed?

Old-fashioned popcorn usually takes 0.7 to 0.8 breath to step on it.

China old popcorn machine is an ancient popcorn machine. The loud noise of popcorn is an interesting memory of many China people born in 1970s and 1980s, including old stoves, gourd-shaped pressure cookers and sacks. This old popcorn machine also appeared in the well-known popular science program "mythbusters" of the American Discovery Channel. This video was madly forwarded on Weibo. Many netizens said that they finally knew how raw corn turned into popcorn. Now it is hard to see such a scene.

Extended data:

The old popcorn machine is actually a pressure vessel. Put the processing raw materials (generally corn, rice, broad beans, yellow rice and other common grains) into the machine and cover it. Turn the head screw with the same force as the booster rod and the booster tube to pressurize the sealing cover. Put the popcorn rack on the bracket, heat the lower part with strong fire, and turn the popcorn machine by hand to make the raw materials in the machine soften evenly.

Due to heating, the pressure in the machine gradually increases. When the required pressure is reached (different raw materials need different pressures), stop heating, twist the popcorn machine to one side and cover the machine mouth with a sack. Put the booster on the small elbow, pull the small elbow hard, and loosen the buckle of the big elbow, so that the cover can be opened under the pressure in the machine, and the high-temperature and high-pressure gas in the machine can be ejected together with the processing raw materials. In the process of injection, due to the rapid drop of external pressure, the gas inside the grain expands rapidly and the grain explodes.