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book 1 - 5th power engineering > chapter 18 > Flashcards

chapter 18 Flashcards

1
Q

An equalizing line is installed around a large gate valve in a steam header because:

a)The valve is difficult to open with pressure on both sides
b)The valve is difficult to close with pressure on one side
c)The valve is difficult to open with pressure on only one side
d)With use of the equalizing line, the valve can be used for throttling

A

c

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2
Q

The tapered plug valve is lubricated because:

a)They must prevent reversal of flow
b)They are commonly used in slurries and with fluids with high-solids content
c)Their rising stem tends to dry out and seize
d)The tapered plug has a tendency to jam in the tapered seat.

A

d

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3
Q

It is easy to determine by sight whether a ball valve is open or closed

True
False
A

true

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4
Q

A check valve:

a)allows flow at regular intervals
b)allows flow in one direction only
c)allows flow in two directions
d)does not allow any flow at all

A

b

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5
Q

The by-pass around a regulating valve should contain a:

a)Non-rising stem gate valve
b)Rising stem gate valve
c)Rising stem globe valve
d)Swing check valve

A

c

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6
Q

The advantage of a rising stem steam stop valve is that:

a)you can tell from a distance if the valve is open or closed
b)It may be easily lubricated
c)The threaded part is not exposed to corrosion by the high temperature steam
d)All of the above

A

d

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7
Q

The butterfly valve:

a)Is among the most expensive types of valve
b)Is a high-pressure drop valve when open
c)Is designed for throttling service
d)Is designed for both full-flow valve and throttling service

A

d

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8
Q

Flow through a swing check valve

a)Controls how fast the check valve closes
b)Changes direction twice
c)Travels in an almost straight line
d)Closes the check valve

A

c

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9
Q

Which style of valve must be installed with attention to direction of flow in the piping system?

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

A

c

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10
Q

A globe valve:

a)is used to throttle flow
b)has a machined centre bore
c)has less restriction in line than a gate valve
d)should be operated either fully open or fully closed

A

a

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11
Q

The needle valve used as a continuous blowdown valve on a boiler is which type of construction:

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

A

c

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12
Q

Plug valves require internal lubrication

True
False
A

true

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13
Q

Non-return valve are used on steam installations only.

True
False
A

false

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14
Q

Ball valves require internal lubrication:

True
False
A

false

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15
Q

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

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

A

a

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16
Q

The butterfly valve:

a) is a quarter-turn valve
b) Is a slow-opening valve
c) Is a safety shut off valve
d) Is a type of plug valve

A

a

17
Q

Non-rising stem valves are:

a) Used where the contents contained in the piping system may corrode or affect the stem
b) Used where headroom is limited
c) Used where it is necessary to determine at a glance whether the valve is open
d) Allowed on hot water systems only

A

b

18
Q

The by-pass around a regulating valve should contain a:

a)Rising stem gate valve
b) Non-rising stem gate valve
c)Swing check valve
d)Rising stem globe valve

A

d

19
Q

A check valve:

a)does not allow any flow at all
b)allows flow in two directions
c) allows flow at regular intervals
d) allows flow in one direction only

A

d

20
Q

which of the following types of valves is used exlusively for the throttling of steam

a. gate
b. ball
c. butterfly
d. globe

A

d

21
Q

a ball valve contains a spherical ________ with a passage bored thorughit to control the fluid flow through the valve body

a. plug
b. ball
c. circle
d. cube

A

a

22
Q

the maximum operating temp for butterfly valve is

a. 500c
b. 1200c
c. 1100c
d. 1500c

A

c

23
Q

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

A

b

24
Q

explain the meaning of 125 SWOG as stamped on a valve body

A

125psi steam water oil or gas

25
Q

What does “wire drawing” refer to in the context of flanges?
A. The process of shaping flanges using a wire.
B. The formation of deep grooves on flanges caused by the scouring action of escaping fluid.
C. A technique for enhancing the strength of flanges.
D. A method for connecting flanges using wire.

A

B

26
Q

All valves not properly or clearly identified should be:

A.Kept for emergency use
B.Rejected
C.Sold for scrap
D.Used in non critical areas
E.Used as they are available

A

b

27
Q

Gate valves consist of a gate-like disc, actuated by a screwed stem and hand wheel that moves _____ the path of flow.

A.Up and down parallel to
B.Perpendicular with
C.Clockwise with
D.Counterclockwise with
E.Up and down at right angles to

A

e

28
Q

The check valve is a valve which prevents _____ in piping.

A.Low flow
B.Reversal of flow
C.Low pressure
D.High pressure
E.High flow

A

b

29
Q

The non-return stop valve is also referred to as a _____ valve.

A.Gate and check
B.Stop and check
C.Globe and stop
D.Ball and stop
E.Stop and gate

A

b

30
Q

The basic type of ball valve requires _____ from the fully open to the fully closed position.

A.One half turn
B.One quarter turn
C.Five turns
D.Two turns
E.One turn

A

b

31
Q

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.Ball
E.Dashpot

A

b

32
Q

Valve packing surrounds the:

A.Disc
B.Bonnet
C.Body
D.Packing gland
E.Stem

A

e

33
Q

Globe valves are ideal for:

A.Remote controlling
B.Isolation valves
C.Reducing flow friction
D.Throttling valves
E.Stop valves

A

d

34
Q

On a steam system the non-return stop valve is connected to the:

A.Continuous blowdown outlet
B.Blowdown outlet
C.Steam boiler outlet
D.Feedwater inlet
E.Safety valve outlet

A

c

35
Q

The valve gland contains the:

A.Disc
B.Wheel
C.Packing
D.Bonnet
E.Body

A

c

book 1 - 5th power engineering (20 decks)

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