Patent ID: 6953045

Claim:
An apparatus comprising: a gas flow line including a motor valve, a control valve, and an outlet regulator, said gas flow line having sufficient volume for stable pressure sensing; a controller for controlling operation of said control valve; an inlet regulator; a first pilot line connecting said inlet regulator to said motor valve; a second pilot line connecting said inlet regulator to said controller; a relief valve connected to said gas flow line at a point downstream of said motor valve and said control valve; said controller being connected via a third line to said gas flow line, and said motor valve being connected via a fourth line to said gas flow line, wherein said third and fourth lines hold gas under pressure in order to sense the pressure in said gas flow line, whereby said controller and said motor valve make adjustments in response to pressure fluctuations via said third and fourth lines to maintain the pressure in said gas flow line at or below a predetermined maximum.