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Instruction Manual
D103551X012
Educational Services
For information on available courses for the Fisher EWNS valve, as well as a variety of other products, contact:
Emerson Automation Solutions
Educational Services - Registration
Phone: 1-641-754-3771 or 1-800-338-8158
E-mail: education@emerson.com
emerson.com/fishervalvetraining
Principle of Operation
EWNS valves are control valves based on the Fisher EW valve product. The valve body and bonnet contain a fluid under
pressure, while the internal valve parts control the flow of the fluid through the valve. The internal parts consist of
gaskets, a cage-seat ring assembly, a plug-stem assembly, and bidirectional seal rings for both cage-seat ring assembly
and plug-stem assembly. The gaskets and cage-seat ring assembly are stationary and held in place inside the valve
body and bonnet by the force applied by the body-to-bonnet bolting. The plug-stem assembly is designed to move up
and down (axially) inside the cage. The stem passes through a hole in the bonnet, and can be moved up and down
(axially) by an external actuator attached to the bonnet. Packing is used between the valve bonnet and plug stem to
prevent the fluid from leaking out of the valve, while still allowing the plug stem to move axially.
Fluid enters one end of the valve. When the stem is pushed down, the plug moves to contact the seat ring, and "closes"
the valve, preventing the fluid from passing through the valve. When the stem is pulled up, the plug disengages from
the seat ring, and slides up through the center of the cage, exposing holes or flow passages in the cage. This allows the
fluid to flow through the seat ring and cage, and exit the valve through the opposite end of the valve which it entered.
By positioning the plug at different "travels" in the cage, the amount of flow through the valve can be controlled.
Lifting Guidelines
WARNING
Failure to follow these lifting guidelines and accepted lifting and rigging practices could result in property damage and
personal injury or death.
All lifting and rigging must be completed in accordance with federal/national/provincial, state and local regulations and
applicable lifting and rigging equipment standards. Only personnel trained in proper lifting and rigging practices shall
perform valve/actuator assembly lifting, rigging and installation. Because each lift will be unique, the method of lifting the
valve assembly, the correct location for attaching and lifting the valve assembly, and what the valve assembly will do when
lifted shall be considered for each lift.
Lifting and rigging equipment used to lift, install or remove a valve assembly or component must be properly selected and
sized for the weight and configuration of the valve assembly or component being lifted. The weight of the complete valve
assembly, including attached accessories, must be taken in consideration for this purpose. The lifting and rigging
equipment must be properly maintained and inspected for damage before each use.
If the valve is supplied with an actuator or handwheel, do not use the actuator or handwheel to lift the complete valve
assembly. Lifting lugs attached to the actuator must not be used to lift the complete valve assembly unless clearly marked
as being rated to support the complete valve assembly weight.
Lifting lugs or other lifting equipment attached to the valve or actuator must never be used to lift or support the weight of
attached piping.
EWNS Valve
March 2022
3
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