Pe - 4Th Class - A2 - Unit 11

Front 1

Valves can be manually operated or have a _______, that may be pneumatically, hydraulically or electrically operated.

Back 1

actuator

Front 2

Gate valves are not suitable for ________.

Back 2

throttled

Front 3

Gate valves are suitable as ______ valves.

Back 3

stop (or isolating)

Front 4

When fully open the resistance is _____ with a gate valve.

Back 4

low

Front 5

Gate valves are prone to wear caused by _____ ________.

Back 5

wire drawing

Front 6

This type of valve is ideal for throttling or regulating flow:

Back 6

globe valve

Front 7

This type of valve has minimal wire drawing and seat erosion.

Back 7

globe valve

Front 8

Single dish globe valves are seldomly used for pipe sizes larger than ____ mm diameter due to

Back 8

305 mm

Front 9

Type of valve that allows for precise flow control.

Back 9

Needle valve

Front 10

Type of valve used extensively for continuous blowoff.

Back 10

needle valve

Front 11

Butterfly valves come in sizes from ____ mm to _______ mm in diameter.

Back 11

25; 3800

Front 12

Butterfly valves are designed for pressure up to:

Back 12

13 800 kPa

Front 13

Butterfly valves are designed for temperatures up to:

Back 13

1100˚C

Front 14

A large butterfly valve often requires a power ________ to position the disk because of the large pressure differential.

Back 14

actuator

Front 15

To open a ball valve in requires a _______ turn.

Back 15

quarter

Front 16

Ball valves require lubrication.

true or false

Back 16

true

Front 17

Larger, high pressure ball valves are constructed with a _______ stem.

Back 17

double

Front 18

Ball valves are manufactured in sizes of ___mm to ________ mm.

Back 18

2 mm; 1000 mm

Front 19

Ball valves are designed for pressures up to:

Back 19

69 000 kPa

Front 20

Ball valves are designed for temperatures from _____˚C to ________˚C.

Back 20

-185˚C to 550˚C

Front 21

This type of valve is suitable for slurries and fluids with high solid content.

Back 21

Ball valve

Front 22

This pressure drop across this valve, in wide open positions, is very low. This valve is also self cleaning.

Back 22

Plug valve

Front 23

This valve prevents the reversal of flow in piping.

Back 23

Check valve

Front 24

Two types of check valves are:

Back 24

• swing check

• life check

Front 25

Check valve which produces a high resistance to flow.

Back 25

swing

Front 26

Check valve which create turbulence.

Back 26

swing

Front 27

To overcome wear and water hammer what can be attached to the disk and what ?

Back 27

a damping mechanism

Front 28

On a lift check valve a __________ can be used to cushion the action of the disk in this design.

Back 28

dashpot

Front 29

If a _______ _______ is used, the lift valve is only suitable for application where a small amoutn of reverse flow is allowed.

Back 29

metal seat

Front 30

Generally a ______ _______ is limited to prevent reverse flow of condensate in steam traps.

Back 30

lift valve

Front 31

The main advantage of a lift valve is its:

Back 31

Simplicity

Front 32

Lift valves are design for use in only ____________ pipelines.

Back 32

Horizontal

Front 33

ASME code, section 1, states that each outlet of a power boiler is to be fitted with a ______ _______ located as close as is practical to the boiler.

Back 33

stop valve

Front 34

Two types of valves commonly used on the steam outlet of a boiler are:

Back 34

gate and globe valve

Front 35

It is recommended to use a stop valve of the outside-screw-and-yoke type with a rising spindle when the outlet is ____ mm pipe size or larger.

Back 35

51 mm

Front 36

A spring-operated reducing valve consists of two main parts separated by a diaphragm. These are:

Back 36

valve housing and the bonnet

Front 37

The main benefit of having an external diaphragm is that it is not affected by the fluid ________. Which results in a lowered lifespan.

Back 37

temperature

Front 38

All reducing valves should be installed with _______ valves on either side.

Back 38

isolating

Front 39

Reducing valves should have a _____ _______ on the low-pressure side.

Back 39

safety valve

Front 40

Which type of valve is preferred for isolating valves?

Back 40

gate

Front 41

By-pass valves should be which type of valve?

Back 41

globe

Front 42

Bronze valves can be used for temperatures up to:

Back 42

280˚C

Front 43

Carbon Steel valves can be used for temperatures up to:

Back 43

425˚C

Front 44

Alloy Steel valves can be used for temperatures up to:

Back 44

650˚C

Front 45

Stainless steel valves can be used for surfaces that are:

Back 45

corrosive

Front 46

Teflon, Teflon impregnated asbestos, graphite asbestos, and semi-metallic are all used as what?

Back 46

Valve packing material

Front 47

3 things required for the ID of valves:

Back 47

• Manufacturers name • Service Designation • Material of Design

Front 48

Stem leaks can be normally fixed by:

Back 48

tightening the packing nut or gland

Front 49

Over tightening valve nuts can cause extra friction resulting in:

Back 49

wear and extra effort closing the valve

Front 50

If tightening the bolts on a bonnet of flange, what should be replaced immediately?

Back 50

the gasket

Front 51

Neglecting to stop leakages on a flange will lead to ________.

Back 51

wiredrawing

Front 52

Valve seats which show deep grooves or damage should be:

Back 52

refaced

Front 53

Slight damage on seats can be refaced with by:

Back 53

grinding the valve disk in on the seat in combination with a grinding compound

Front 54

Extensive damage of the seat should be refaced with a:

Back 54

reseating tool

Front 55

When the valve in equipped with a renewable seat and the disk and seat are both extensively damage, what should be done?

Back 55

Replace both (it's cheaper than repairing)

Front 56

Seating surfaces on gate valves are _______ than those on globe valves.

a) softer b) harder

Back 56

b) harder