Amico Dome Loaded Manifold NFPA - Manual (Page 20)

20 Amico Pipeline
High pressure gas is provided to the left and right manifold bank inlets via cylinders, pigtails and header assemblies.
Flow of high pressure gas through the left and right side of the manifold is identical, each passing through a master valve
located on the header and then directly to a bank regulator.
Bank regulators reduce incoming cylinder pressures to an intermediate pressure. Bank regulators are referred to as a
“dome loaded” type of regulator. These regulators have an internal adjusting spring manually set at a specific pressure
similar to other diaphragm type pressure regulators. In addition to an internal adjusting spring, bias pressure may be
applied to the dome of the regulator (on the adjusting spring side of diaphragm) thus boosting pressure above what
is manually set by the adjusting spring. This output pressure boost will be approximately equal to the amount of bias
pressure.
For example, if a bank regulator is manually adjusted to 100 psi via the internal adjusting spring, and a dome bias
pressure of 55 psi is applied, the output pressure will increase to approximately 155 psi (100 + 55). When the bias
pressure is removed, the output pressure setting will return to 100 psi.
Outputs of both the left and right bank regulators pass through check valves and connect together upstream of the dual
line regulator assembly. An intermediate relief valve protects components between the bank and line regulators in the
event of a bank regulator seat failure.
The dual line regulator assembly consists of two line regulators plumbed in parallel with upstream and downstream
isolation 1/4” turn ball valves. Output of both the line regulators tee together and exit at the manifold’s main outlet. A line
relief valve along with a line pressure gauge is connected to the manifold’s main outlet.
Outlet pressure is then routed to a dome regulator reducing pressure to 55 psi at the solenoid switch. The solenoid
switches 55 psi (dome bias pressure) to one of the bank regulators. When one bank regulator is supplied bias pressure,
the other bank’s dome regulators are vented to the atmosphere. An electronic circuit board controls the solenoid valve
based upon the input received from the right and left pressure transducer. The solenoid valve directs bias pressure to the
bank designated as primary.
Manifolds designed for 55 psi nominal output pressure do not incorporate a Pilot regulator. Full line pressure (55 psi) is
routed directly to the solenoid valve which is used as dome bias pressure.
Gas Flow Through the Manifold