Amico Dome Loaded Manifold Nema-4 NFPA - Manual (Page 21)

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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 manifold is exactly the same, 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 specifi c pressure
similar to other diaphragm type pressure regulators. In addition to internal adjusting spring, bias pressure may be
applied to the dome of the regulator (adjusting spring side of diaphragm) thus boosting pressure above what is manu-
ally 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 100psi via internal adjusting spring, and a dome bias pressure
of 55psi is applied, the output pressure will increase to approximately 155psi (100 + 55). When the bias pressure is re-
moved, the output pressure setting will return to 100psi.
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. Solenoid switches
55psi (dome bias pressure) to one of the bank regulators. When one bank regulator is supplied bias pressure, the other
bank’s dome regulator’s is 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 55psi nominal output pressure do not incorporate a Pilot regulator. Full line pressure (55psi) is
routed directly to the solenoid valve which is used as dome bias pressure.
Gas Flow Through the Manifold