Mile High wrote:
Actually it provides back pressure on the on the cylinder furthest from the main regulator, to prevent the safety valve from slamming shut if you open it too fast. Didn't used to be an issue until the design of the cylinders changed to the high flow safety shutoff.
They are cheap regulators, and are a hazard greater than what they are trying to overcome - 2 of mine have leaked. I just remove them altogether.
The excess flow shut-off is in the hose......not in propane cylinder.
Propane cylinder does have a spring loaded valve that closes when hose is disconnected. Can not get flow from cylinder without hose attached.