Book 1 Chapter 18: Introdution To Valves Flashcards
Which of the following types of valves is used exclusively for the throttling of steam?
A) Gate
B) Ball
C) Butterfly
D) Globe
D) Globe
The maximum operating temperature for a butterfly valve is:
A) 500ºC (932ºF)
B) 1200ºC (2190ºF)
C) 1100ºC (2012ºF)
D) 1500ºC (2730ºF)
C) 1100ºC (2012ºF)
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
B) High pressure steam lines
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
B) Disc and seat
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
B) Needle valve
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
C) 1,2,3
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
D) Prevent the back flow of steam
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
D) Tapered plug valve
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
D) Allows flow in one direction only
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
A) Lift check valve
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
C) Globe valve
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
B) 1,2,4
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
D) Ball valve
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
A) Increase the regulated pressure downstream of the valve
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
C) Wrong materials of construction
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
D) Always tighten up bolts evenly
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
B) Rejected
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
B) Triple duty
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
A) Material designation
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
B) Steam boiler outlet
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)
C) 28kPa (4psi)
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
B) Tapered or straight cylinder
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
A) Stop and check
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
A) 90º
Gate valves are suitable as _______ valves.
A) Control
B) Remote controlled
C) Throttling
D) Diverting
E) Stop (or isolating)
E) Stop (or isolating)
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
C) High pressure steam lines
