How the EFV functions
The Powell Flow Limiter prevents catastrophic leakage by automatically
tripping when gas flow exceeds a predetermined rate. When the gas
flow rate reaches the predetermined critical value, the forces on
the ball exceed the opposing force on the spring, thus causing the
ball to seal against the bored diameter. Bleed-by is achieved with
a small notch in the ball seat at the bored diameter.
Powell Flow Limiters are currently available for operation at trip
flow rates of 400, 800, and 1800 SCFH (measured at 10 psig). These
valves are designed to provide dependable maintenance-free operation
for many years. The valve's design and large port area allow particular
matter to pass through without damage or build-up. These excess flow
valves provide extremely consistent trip flow rates and very low pressure
drop across the valve. Carefully controlled bleed-by assures automatic
reset at a pressure differential as low as 1.5 psi. |
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Specifications
(Powell Flow Limiters)
Valve Body ......................360 brass
Spring...............................300 series stainless steel
Ball...................................Precision ground nylon
O-ring...............................Buna-N (Nitrile) |
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