27 / 60
cycles. The benchmark in terms of seat leakage was less
than 3000 ml/min. for a valve of DN 500 mm based on
BS 6364 and a maximum allowable fugitive emission of
≤1.0•10-3 mbar
∙
l
∙
s-1 at any time during the cycles. The
valve was tested with helium at 19 bar (275 psi) test
pressure, whereas the seat leakage and fugitive emission
were measured after 20, 40, 80, 150, 300 and 500 cycles.
After results of the testing were made clear, the test
institute, ITIS BV, certified that the seat leakage never
exceeded a low value of 590 ml/min. and, after 500 cycles,
absolute zero leakage was achieved. Moreover, the
fugitive emission at the bonnet and trunnion gaskets of
the top entry valve never exceeded a value of
≤1.0•10-5 mbar
∙
l
∙
s-1. The round seat and sealing
geometry of QUADAX butterfly valves is a totally friction
free metal-to-metal design. Thanks to this round
geometry, after a couple of hundred cycles, the seat and
sealing ring is literally looped-in, and provides the
greatest level of tightness, even if material is shrinking
and expanding due to extreme temperature differences.
At the conclusion of the testing, which was a
replication of a real life application, and in the
liquefaction and storage process of LNG terminals, where
the valves are critical components at each stage and their
performance and reliability are crucial for environmental
and safety reasons, the results are clear. The QUADAX
quadruple offset butterfly valve outperformed the severe
thermal endurance test and provided evidence of its
quality and reliability in LNG installations.
Additionally, QUADAX top entry butterfly valves fully
satisfied the requirements of the EN 1473-2016
specifications for valves, and are specifically designed for
LNG applications where control and maintenance work
can be performed safely and easily in the installed
position without further risks for the service personnel.
Utilising the new technology of the four offset butterfly
valve, costly downtime, pass through leakage and loss of
product issues can be reduced to a minimum, allowing for
valve maintenance overall to be more easily planned.
For these applications and processes, top entry valves
are preferred since the central top flange can be removed
and all internal components can be easily extracted from
the body. This is not the case for side entry valves
marketed by many valve manufacturers. By exceeding
expectations with the better performing technology and
design, Müller Quadax GmbH has been awarded a large
contract for top entry butterfly valves replacing side entry
valves in an existing LNG installation, including an
upcoming extension with one new LNG terminal. Located
in Europe, this terminal enables access into the
Northwest European gas market, with an initial
throughput capacity of 12 billion m³/yr, which in the
future will be extended to 16 billion m³/yr. This terminal
is also equipped with three loading bays for trucks, and a
dedicated jetty for smaller (bunker) vessels.
Due to the four offset design and remarkable
precision in manufacturing, the QUADAX butterfly valves
have provided evidence of outstanding performance in
cryogenic applications. These attributes perform just as
dramatically in high temperatures, allowing QUADAX to
market in the most extreme applications for all
systems.