Valve Basics

Question 1

What are the 4 main functions

Answer 1

Starting/stopping flow - block valves

Controlling the flow - control valves

Preventing back flow - check valves

Relieving excess pressure - safety valve

Question 2

Function of valve body

Answer 2

Holds everything together (principle part of valve assembly)

Connects to inlet and outlet piping

Question 3

Describe function of the bonnet

Answer 3

Houses the stem, disk and packing

Question 4

List the valve trim components

Answer 4

Disk
Seat
Stem
Sleeves to guide stem

Question 5

Function of hand wheel

Answer 5

Allows valve to be operated manually

Question 6

Describe function of the yoke and stuffing box

Answer 6

Yoke - attached to top of bonnet, supports the hand wheel

Stuffing box - is a cavity inside the valve bonnet that holds the packing material

Question 7

Describe the function of a gland follower

Answer 7

Fits around stem. On top of packing gland, exerts pressure on the packing gland

Question 8

Function of the Packing gland

Answer 8

Ring shaped piece that fits around stem and compresses packing into the stuffing box

Question 9

What are the two types of motions for a valve trim?

Answer 9

Linear and rotational

Question 10

What is a plug valve?

Answer 10

A wedged shape cyclometer, rotational motion

Question 11

List 3 Trim shapes (globe valves)

Answer 11

Linear, equal percentage, quick opening

Question 12

What is a solenoid?

Answer 12

It is instant. Uses a magnetic field

Question 13

Positioner

Answer 13

Control sends a signal to the positioner

Positioner compares its current placement via the stem linkage and will make adjusts from the controller signal output.

Positioner directs air to the actuator to a more open or closed position to status based on the controler signal.

The Positioner will confirm its new current valve position improving actuator response