sliding stem control valve terminology

Question 1

Actuator
Spring

Answer 1

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

Question 2

Angle Valve

Answer 2

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

Question 2

Actuator Stem

Answer 2

The part that connects the actuator to the valve stem and transmits motion
(force) from the actuator to the valve

Question 3

Valve Bonnet

Answer 3

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

Question 4

Bushing

Answer 4

A device that supports and/or guides moving parts such as valve stems

Question 5

Cage

Answer 5

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

Question 6

Closure
Member
Guide

Answer 6

That portion of a closure member that aligns its movement in either a cage,
seat ring, bonnet, bottom flange, or any two of these

Question 7

Closure
Member

Answer 7

he movable part of the valve that is positioned in the flow path to modify the
rate of flow through the valve

Question 8

Cylinder

Answer 8

The chamber of a piston actuator in which the piston moves

Question 9

Diaphragm

Answer 9

A flexible, pressure responsive element that transmits force to the diaphragm
plate and actuator stem.

Question 10

Diaphragm
Actuator

Answer 10

A fluid powered device in which the fluid acts upon a flexible component, the
diaphragm

Question 11

Diaphragm
Case

Answer 11

A housing, consisting of top and bottom section, used for supporting a
diaphragm and establishing one or two pressure chambers.

Question 12

Diaphragm
Plate

Answer 12

A plate concentric with the diaphragm for transmitting force to the actuator
stem

Question 13

Direct
Actuator

Answer 13

A diaphragm actuator in which the actuator stem extends with increasing
diaphragm pressure

Question 14

Globe Valve

Answer 14

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

Question 15

Packing Box

Answer 15

The part of the bonnet assembly used to seal against leakage around the
closure member stem

Question 16

Piston

Answer 16

A movable pressure responsive element that transmits force to the piston
actuator stem

Question 17

Piston Type
Actuator

Answer 17

A fluid powered device in which the fluid acts upon a movable piston to
provide motion
to the actuator stem

Question 18

Plug

Answer 18

A term frequently used to refer to the closure member

Question 19

Port

Answer 19

The flow control orifice of a control valve

Question 20

Reverse
Actuator

Answer 20

A diaphragm actuator in which the actuator stem retracts with increasing
diaphragm pressure

Question 21

Seat

Answer 21

The area of contact between the closure member and its mating surface that
establishes valve shut-off

Question 22

Seat Ring

Answer 22

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

Question 23

Spring
Adjustor

Answer 23

A fitting, usually threaded on the actuator stem or into the yoke, to adjust the
spring compression

Question 24

Spring Seat

Answer 24

A plate to hold the spring in position and to provide a flat surface for the
spring adjustor to contact

Question 25

Stem
Connector

Answer 25

The device that connects the actuator stem to the valve stem

Question 26

Yoke

Answer 26

The structure that rigidly connects the actuator power unit to the valve.