sliding stem control valve terminology Flashcards
Actuator
Spring
A spring, or group of springs, enclosed in the yoke or actuator casing that
moves the actuator stem in a direction opposite to that created by diaphragm
pressure
Angle Valve
A valve design in which one port is co-linear with the valve stem or actuator,
and the other port is at a right angle to the valve stem
Actuator Stem
The part that connects the actuator to the valve stem and transmits motion
(force) from the actuator to the valve
Valve Bonnet
The portion of the valve that contains the packing box and stem seal and can
guide the stem. It provides the principal opening to the body cavity for
assembly of internal parts or it can be an integral part of the valve body. It can
also provide for the attachment of the actuator to the valve body
Bushing
A device that supports and/or guides moving parts such as valve stems
Cage
A part of a valve trim that surrounds the closure member and can provide flow
characterization and/or a seating surface. It also provides stability, guiding,
balance, and alignment, and facilitates assembly of other parts of the valve
trim
Closure
Member
Guide
That portion of a closure member that aligns its movement in either a cage,
seat ring, bonnet, bottom flange, or any two of these
Closure
Member
he movable part of the valve that is positioned in the flow path to modify the
rate of flow through the valve
Cylinder
The chamber of a piston actuator in which the piston moves
Diaphragm
A flexible, pressure responsive element that transmits force to the diaphragm
plate and actuator stem.
Diaphragm
Actuator
A fluid powered device in which the fluid acts upon a flexible component, the
diaphragm
Diaphragm
Case
A housing, consisting of top and bottom section, used for supporting a
diaphragm and establishing one or two pressure chambers.
Diaphragm
Plate
A plate concentric with the diaphragm for transmitting force to the actuator
stem
Direct
Actuator
A diaphragm actuator in which the actuator stem extends with increasing
diaphragm pressure
Globe Valve
A valve with a linear motion closure member, one or more ports, and a body
distinguished by a globular shaped cavity around the port region
Packing Box
The part of the bonnet assembly used to seal against leakage around the
closure member stem
Piston
A movable pressure responsive element that transmits force to the piston
actuator stem
Piston Type
Actuator
A fluid powered device in which the fluid acts upon a movable piston to
provide motion
to the actuator stem
Plug
A term frequently used to refer to the closure member
Port
The flow control orifice of a control valve
Reverse
Actuator
A diaphragm actuator in which the actuator stem retracts with increasing
diaphragm pressure
Seat
The area of contact between the closure member and its mating surface that
establishes valve shut-off
Seat Ring
A part of the valve body assembly that provides a seating surface for the
closure member and can provide part of the flow control orifice
Spring
Adjustor
A fitting, usually threaded on the actuator stem or into the yoke, to adjust the
spring compression
Spring Seat
A plate to hold the spring in position and to provide a flat surface for the
spring adjustor to contact
Stem
Connector
The device that connects the actuator stem to the valve stem
Yoke
The structure that rigidly connects the actuator power unit to the valve.
