Book 1 Chapter 18: Introdution 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

The maximum operating temperature for a butterfly valve is:
A) 500ºC (932ºF)
B) 1200ºC (2190ºF)
C) 1100ºC (2012ºF)
D) 1500ºC (2730ºF)

Answer 2

C) 1100ºC (2012ºF)

Question 3

Which of the following applications is a plug valve not suitable for?
A) Water treatment
B) High pressure steam lines
C) Chemical industries
D) Gas supply lines

Answer 3

B) High pressure steam lines

Question 4

Regular inspection of a valve is important and items which require close scrutiny are the:
A) Steam and body
B) Disc and seat
C) Hand wheel and packing
D) Seat and stem
E) Stuffing box and spindle threads

Answer 4

B) Disc and seat

Question 5

The valve that provides very fine flow control is the:
A) Check valve
B) Needle valve
C) Ball valve
D) Butterfly valve
E) Gate valve

Answer 5

B) Needle valve

Question 6

Advantages of Butterfly valves are that they:
1. Are relatively light and easy to operate
2. Are self cleaning
3. Provide negligible pressure drop when fully open
4. Can have the disc lubricated while in operation
5. Are self adjusting so alignment is not required during installation

A) 1,3
B) 1,2,5
C) 1,2,3
D) 2,4
E) 3,4,5

Answer 6

C) 1,2,3

Question 7

The purpose of the non-return valve is to:
A) Drain condensate from the main steam header
B) Prevent water from entering the steam header
C) Regulate the flow of steam from the boiler
D) Prevent the back flow of steam
E) Prevent the safety valve from popping

Answer 7

D) Prevent the back flow of steam

Question 8

A valve which requires specific and routine lubrication is the:
A) Butterfly valve
B) Check valve
C) Pressure reducing valve
D) Tapered plug valve
E) Globe valve

Answer 8

D) Tapered plug valve

Question 9

A check valve is a valve that:
A) Has a locking spindle
B) Allows flow at regular intervals
C) Does not allow any flow at all
D) Allows flow in one direction only
E) Allows flow in two directions

Answer 9

D) Allows flow in one direction only

Question 10

A valve that often contains a dashpot to cushion the action of the valve is the:
A) Lift check valve
B) Needle valve
C) Swing check valve
D) Safety valve
E) Pressure regulating valve

Answer 10

A) Lift check valve

Question 11

A valve having minimum wire drawing and seat erosion is the:
A) Gate valve
B) Plug valve
C) Globe valve
D) Hand valve
E) Wedge gate valve

Answer 11

C) Globe valve

Question 12

A gate valve:
1. Has less restriction in a line than a globe valve
2. Should be operated either fully open or fully closed
3. Is used to throttle flow
4. Is used for different applications than a globe valve

A) 2,3,4
B) 1,2,4
C) 1,3,4
D) 1,2,3,4
E) 2,4

Answer 12

B) 1,2,4

Question 13

A valve that has the greatest capability of handling slurries and fluids with high suspended solids is the:
A) Needle valve
B) Globe valve
C) Plug valve
D) Ball valve
E) Gate valve

Answer 13

D) Ball valve

Question 14

Increasing the spring tension of a pressure regulating valve will:
A) Increase the regulated pressure downstream of the valve
B) Close the valve tight
C) Cause the valve to go to the wide open position
D) Decrease the regulated pressure downstream of the valve
E) Reduce or minimize the cycling or “hunting” of the valve

Answer 14

A) Increase the regulated pressure downstream of the valve

Question 15

Relative to valves, a frequent cause of serious accidents is due to:
A) Inadequate operational training
B) Valves being of the wrong size
C) Wrong materials of construction
D) Manufacturing defects
E) A lack of valve maintenance

Answer 15

C) Wrong materials of construction

Question 16

When valve stem leaks are fixed by tightening the packing gland:
A) Tighten the packing as much as possible to prevent future leaks
B) Valve packing doesn’t require maintenance
C) Use a thicker packing
D) Always tighten up bolts evenly
E) Leave some leakage to lubricate the rotating shafts

Answer 16

D) Always tighten up bolts evenly

Question 17

All valves not properly or clearly identified should be:
A) Used in non critical areas
B) Rejected
C) Sold for scrap
D) Kept for emergency use
E) Used as they are available

Answer 17

B) Rejected

Question 18

On a hot water heating system the stop/balance check valve is also known as a ______ valve.
A) Double duty
B) Triple duty
C) Pressure balancing
D) Non-return
E) Temperature control

Answer 18

B) Triple duty

Question 19

All valves must be properly identified with one of the markings indicating the:
A) Material designation
B) Mass of the valve
C) Type of packing used
D) Type of valve
E) Size of the valve

Answer 19

A) Material designation

Question 20

On a stem system the non-return stop valve is connected to the:
A) Continuous blowdown outlet
B) Steam boiler outlet
C) Blowdown outlet
D) Safety valve outlet
E) Feedwater inlet

Answer 20

B) Steam boiler outlet

Question 21

Ideally with a hot water heating installation the minimum pressure of ______ should be maintained on the highest heating unit in the building.
A) 100kPa (14.5psi)
B) 50kPa (7.3psi)
C) 28kPa (4psi)
D) 20kPa (2.9psi)
E) 10 kPa (1.5psi)

Answer 21

C) 28kPa (4psi)

Question 22

The plug valve consists of a ________ containing a hole that is inserted into the cavity of the valve body.
A) Diaphragm
B) Tapered or straight cylinder
C) Disc
D) Dashpot
E) Ball

Answer 22

B) Tapered or straight cylinder

Question 23

The non-return stop valve is also referred to as a ________ valve.
A) Stop and check
B) Gate and check
C) Globe and stop
D) Ball and stop
E) Stop and gate

Answer 23

A) Stop and check

Question 24

Butterfly valves use a flat disc that can be rotated through ________ from the fully open to the fully closed position.
A) 90º
B) 30º
C) 180º
D) 60º
E) 45º

Answer 24

A) 90º

Question 25

Gate valves are suitable as _______ valves.
A) Control
B) Remote controlled
C) Throttling
D) Diverting
E) Stop (or isolating)

Answer 25

E) Stop (or isolating)

Question 26

Which of the following application is a plug valve not suitable for?
A) Water treatment plants
B) Gas supply lines
C) High pressure steam lines
D) Pulp and paper industries
E) Chemical industries

Answer 26

C) High pressure steam lines