Why doesn’t the flame from a propane torch travel back to the can and blow it up?

Question

I’ve always been a little embarrassed to ask, but when I have, say, a propane torch, how come the flame doesn’t go back through the line and blow up the can?

In: Engineering

Answer 1

People have answered this for fuel-only torches, but you also have oxyacetylene torches where you supply both oxygen and acetylene. In this case the flame can indeed travel back, known as a flashback. Care and equipment is required to prevent it or at least limit damage.