Chapter 21 Introduction to Valves

Question 1

Which of the following types of valves is used exclusively for the throttling of steam?

a) Gate
b) Ball
c) Butterfly
d) Globe

Answer 1

d) Globe

Question 2

A ball valve contains a spherical ______ with a passage bored through it to control the fluid flow through the valve body.

THIS IS A SHORT ANSWER QUESTION

Answer 2

Plug

Question 3

The maximum operating temperature for a butterfly valve is:

a) 500 C (932 F)
b) 1200 C (2190 F)
c) 1100 C (2012 F)
d) 1500 C (2730 F)

Answer 3

c) 1100 C (2012 F)

Question 4

Which of the following applications is a plug valve not suitable for?

a) Water treatment plants
b) High pressure steam lines
c) Chemical industries
d) Gas supply lines

Answer 4

b) High pressure steam lines

Question 5

Explain the meaning of 125 SWOG as stamped on a valve body.

THIS IS A SHORT ANSWER QUESTION.

Answer 5

125 SWOG: refers to 125 psi steam, water, oil, or gas, or this rating can be just 125 S: steam only.

Question 6

Explain the meaning of wire drawing in reference to flanges.

THIS IS A SHORT ANSWER QUESTION.

Answer 6

Wire drawing is the forming of deep grooves, running from the centre of the flange to the outside, caused by the scouring action of the escaping fluid.