Valves, Pipe Fittings and Piping

Question 1

what is the function of a check valve?

Answer 1

to permit the flow of the fluid in one direction only

Question 2

a gate valve is an example of what class of valves?

Answer 2

stop valves

Question 3

what is the most common stop valve?

Answer 3

globe valve

Question 4

what is the purpose of a bridge wall marking on a glove valve?

Answer 4

indicate the direction of flow

Question 5

what type of valve is always open or always closed, and does not regulate fluid flow?

Answer 5

gate valve

Question 6

what is meant by the term rising stem gate valve?

Answer 6

both the gate and the stem move upward when the valve is opened

Question 7

what prevents gate valves used in high pressure steam systems from binding?

Answer 7

flexible gates

Question 8

what are the disks and seats of valves used in high temperature steam systems surfaced with?

Answer 8

satellite

Question 9

what type of valve is shaped to hold a cylindrical or tapered plug?

Answer 9

plug valve

Question 10

what are plug valves commonly used for?

Answer 10

petcocks on auxiliary machinery

Question 11

what type of valve is a combination gate valve and plug valve?

Answer 11

piston valve

Question 12

what determines the tightness of a piston valve?

Answer 12

the closeness of fit between the piston and the inside of the cylinder

Question 13

what type of valve is used to make relatively fine adjustments?

Answer 13

needle valve

Question 14

what is the needle valve installed on an auxiliary turbine used for?

Answer 14

as an overload nozzle

Question 15

what type of valve is light in weight, takes up less space than a gate or globe valve, and is relatively quick acting?

Answer 15

butterfly valve

Question 16

how far must a butterfly valve be rotated to pen or close the valve?

Answer 16

1/4 turn or 90 degrees

Question 17

what type of seat does a butterfly valve have?

Answer 17

resilient

Question 18

what type of check valve, does the disk move up and down in response to changes in the pressure of incoming fluid?

Answer 18

lift check

Question 19

what type of check valve, does the disc move in an arc to open or close the valve?

Answer 19

swing check

Question 20

on a stop check valve, the maximum lift of the disk is controlled by?

Answer 20

the position of the valve stem

Question 21

what type of valve opens automatically when the pressure in the line or in the unit becomes too high?

Answer 21

relief valve

Question 22

what prevents a relief valve from lifting at normal operating pressure?

Answer 22

spring tension

Question 23

how are relief valves set?

Answer 23

by the adjusting screw or adjusting nuts

Question 24

at what pressure does the combination exhaust relief valve lift?

Answer 24

2 psi above auxiliary exhaust line pressure

Question 25

what type of valve, gives an audible warning to the operator, when it lifts?

Answer 25

sentinel valve

Question 26

what are two opposing forces on a spring loaded reducing valve?

Answer 26

the downward force of the spring; the upward force of steam pressure

Question 27

on a spring loaded reducing valve, what determines the position of the auxiliary valve?

Answer 27

position of the controlling diaphragm

Question 28

automatic unloading valves are installed to exhaust to what major components?

Answer 28

main and auxiliary condensers

Question 29

what is the function of an unloading valve?

Answer 29

to discharge steam from the auxiliary exhaust line to the condenser whenever the auxiliary exhaust exceeds 15 psi

Question 30

what comments is used when it is necessary to take suction from one of several sources and discharge to another unit or several units of the same or a separate group?

Answer 30

valve manifold

Question 31

what allows an operator certain valves from distant locations?

Answer 31

remote operating gear

Question 32

what is the cooling source for the inline desuperheater?

Answer 32

feedwater

Question 33

what device is installed in steam lines to drain condensate from the lines without allowing steam to escape?

Answer 33

steam trap

Question 34

what type of steam traps are considered to be mechanical type?

Answer 34

ball float and bucket type

Question 35

how is the operation of a bellows type steam trap controlled?

Answer 35

by the expansion of the vapor of volatile liquid is enclosed in the bellows

Question 36

what type of steam trap operates under the principle that hot water under pressure flashes into steam when the pressure is reduced?

Answer 36

impulse

Question 37

what is the only moving part in an impulse steam trap?

Answer 37

the disk

Question 38

constant flow drain orifices are used in what systems?

Answer 38

150 psi or above where condensate load and pressure remain neat constants

Question 39

what type of steam trap relies on variable density of condenser?

Answer 39

orifice

Question 40

what type of steam trap uses dissimilar metals to operate?

Answer 40

bimetallic

Question 41

where can installations and other information be found pertaining to flange shields?

Answer 41

NSTM 505

Question 42

what are two types of piping expansion joints used onboard ship?

Answer 42

sliding and flexible type

Question 43

what type of piping expansion joint absorbs motion by the movement of a bellows or some similar device?

Answer 43

flexible type

Question 44

what does a valve that has a marking on the body 2000 WOG indicate?

Answer 44

valve is suitable for water, oil and gas service at 2000 psi

Question 45

how is tubing identified in the Navy?

Answer 45

by outside diameter (OD) and by actual measured wall thickness

Question 46

what is the composition of copper nickel alloy tubing used onboard surface ships?

Answer 46

90 percent copper and 10 percent nickel

Question 47

what are two classes of packing and gasket joints?

Answer 47

moving and fixed

Question 48

what type of joint uses gasket material?

Answer 48

fixed

Question 49

what type of joint uses packing material?

Answer 49

moving

Question 50

a fixed joint is identified by the first digit in the symbol number, which would be?

Answer 50

two

Question 51

a moving joint is identified by the first digit in the symbol number, which would be?

Answer 51

one

Question 52

what is used to identify each type or style of packing and gaskets?

Answer 52

symbol number

Question 53

what does the second digit of the symbol number indicate?

Answer 53

packing or gasket composition

Question 54

how can practically all shipboard packing and gasket problems be solved?

Answer 54

by proper selection from the packing and gasket chart

Question 55

low pressure packing must never be used to pack what type of system valves?

Answer 55

high pressure

Question 56

what type of packing is constructed of 100 percent graphite?

Answer 56

Corrugated ribbon packing (CRP)

Question 57

what lubricates the corrugated ribbon packing?

Answer 57

graphite

Question 58

what kind of warning stickers must be affixed to all corrugated ribbon containers?

Answer 58

WARNING: CRP conducts electricity

Question 59

what is the purpose of using graphite filament yarn (GFY) for the first and last packing rings on valves packed with corrugated ribbon?

Answer 59

they are used as anti extrusion rings to prevent the corrugated ribbon packing from being forced out of the stuffing box

Question 60

what systems do not sue corrugated ribbon packing?

Answer 60

fuel oil and lube oil systems

Question 61

how is the outlet temperature of the inline desuperheater controlled?

Answer 61

by thermostatic and diaphragm control valve

Question 62

where can detailed information on the selection of insulation, lagging, and fastening be found?

Answer 62

NSTM 635

Question 63

a tubular product is called pipe if its size is identified by what?

Answer 63

Iron pipe size (IPS) and by reference to wall thickness schedule of piping

Question 64

how are flanges installed in nonferrous systems?

Answer 64

by brazing

Question 65

how are steel flanges installed?

Answer 65

by welding

Question 66

when removing lagging, if you are unsure of what material you are working with, who should you contact immediately?

Answer 66

your supervisor

Question 67

on ships with steam atomization, what is used to lag the atomization piping at the burner front?

Answer 67

epoxy coating

Question 68

what are three positions of the combination exhaust relief valve?

Answer 68

normal, relief and safety

Question 69

what position of the combination relief valve is used, when performing turbine overhaul?

Answer 69

safety position