LP regulator at altitude
Does a LP regulator maintain a constant 11"+/- WC pressure as altitude increases? It would seem that as atmospheric pressure decreases that less force would be exerted on the diaphragm thereby changi...
Forum Discussion
Old-Biscuit wrote:joshuajim wrote:
OK, I got my thinking backwards. The spring is augmented by air pressure on the diaphragm as indicated on the attached pic. This would result in decrease in output pressure as you gain altitude, which would be a good thing.
Regulator
Yes there are vents (2 of them) on a 2-stage regulator.
One small on high pressure side and one large on low pressure side.
They do allow for air movement in/out as diaphragm moves.
Spring tension is spring tension regardless of atmospheric pressure.
Spring tension is pre-set based on desired out put.
The vents provide a means for exhausting gas if internal relief valves open OR as 'leak' detector should diaphragms crack
It's exactly the diaphragm vent that allow atmospheric pressure to be exerted on the diaphragm whether it be 14.7 PSI or some lesser amount. On a 2.5" diaphragm that could ne 72# (if the opposing pressure was nil :) .The pressure in the tank has little bearing on the regulatory function until it gets very low.
