Originally Posted By Jack L
im having a little trouble understanding how a simmer ring on a penny alcohol stove is supposed to work. i assumed the idea was to restrict the flow of vapor, reducing the flame. in the past, when ive tried to use a simmer ring, the flames stayed roughly the same, just funneled toward the center, and the simmer ring burned up.

ive also tried reducing the number of jets to make a designated simmer stove, but instead of twelve 1" high flames, i get six 2" or 3" flames.

can any of you helpful folks explain the physics of a simmer ring, or maybe point me in the right direction?


For an "open cup" stove design, the feedback heat that vaporizes the fuel in the reservoir conducts from the flame down through the hot gas vapor and into the throat. Narrowing the throat diameter reduces the cross-sectional area of the conductive pathway, which makes a proportional reduction in feedback wattage. If the flame is in contact with the simmer ring, and the simmer ring can conduct heat to the metal of the fuel reservoir, you will get additional feedback that violates this linear proportionality rule, so the change won't be exactly linear (a proportional % change).

A penny stove is a pressurized stove, not an open cup stove. It conducts heat to the reservoir fuel from the contacts of the flaming jets emerging from the side of the can. I don't how a simmer ring could possibly be used in this instance unless the pressurized stove has an open throat like a Trangia.

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