| The valve, which is similar to the Fig 245 design, is made
specifically to handle the pipeline medium or is made to customer order. It is
intended that this valve can be customized specifically for services that cannot
be handled by the Fig 245, and a wide range of options are offered for this
purpose.
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As with all 'ATVAL'
knife gate
valves the design incorporates positive sealing where the blade seals in its
face rather than the blade's edge and it uses the pipeline pressure to assist
closure. Wedges cast into the valve body, which acts to properly orientate the
blade during closure, aids closure at low pressures. The wedges also apply a
positive closing force to the blade, even without pipeline pressure assistance
and they also provide structural support for the gate against sudden backflow
conditions such as water hammer or sudden pump isolation.
It is a single seated valve, which is
considered 'Uni-directional' with regard to sealing. All 'ATVAL' single seated knife gate valves are rated for full
reverse pressure in the closed position. Although leakage in the reverse
position may exceed the standard, damages to the valve or substantial leakage
will not occur.
The flow directional arrow cast into the side of the valve body indicates the
direction of the flow. The valve must always be installed with the arrow
pointing in the same direction as the flow stream. |
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