Jason's questions

Question 1

What is a shroud band

Answer 1

Thin strip of metal holds blades together on the outer edge, used to stiffen the blades against vibration and contains the path of steam through the moving blades

Question 2

2 most important clearances on a turbine

Answer 2

Axial and Radial

Question 3

4 reasons to use a curtis stage

Answer 3

• allows for use of high pressure / high temperature steam
• allows for a high temperature drop
• reduced length of rotor
• less expansion and contraction problems

Question 4

4 trips on a steam turbine

Answer 4

• high vibration
• low lube oil pressure
• high back pressure
• high thrust bearing temperature
• Overspeed trip

Question 5

What causes grooving

Answer 5

AKA Channeling, dissolved gasses in the condensate returns lowers pH and leads to grooving in the return line piping

Question 6

Primary concern of super heater tube failure

Answer 6

Inadequate steam flow through the tubes during start up or low flow conditions leads to overheating of the tubes. Opening the super heater vent valve immediately after lighting off will maintain the necessary steam flow until the boiler is coming online at which the vent valve can be closed

Question 7

How many governors are needed to operate a turbine

Answer 7

2, overspeed or emergency trip and main governor

Question 8

3 types of economizers

Answer 8

Parallel flow, counter flow, or a combination of the two

Question 9

Who can adjust safety valve settings

Answer 9

the manufacturer or his authorized representative

Question 10

Reasons why you would lose vacuum on a condenser and how would you correct

Answer 10

• low cooling water flow rate
• high inlet cooling water temp
• excessive air in leakage
• steam jet air ejector not working ( air removal equipment)
• debris reducing heat transfer and interrupting cooling water circulation

Start another circulating pump, put extra air removal equipment in service, backwash condenser

Question 11

minimum width of bearing surface for manhole gaskets

Answer 11

11/16 in

Question 12

maximum thickness for manholes \ handholes

Answer 12

1/4 in when compressed

Question 13

Water column connections, gage glass connections pipe sizes

Answer 13

water column at least NPS 1’’, gage glass at least NPS 1/2 ‘’

Question 14

what happens to temp, pressure, entropy and enthalpy when steam passes through a prv

Answer 14

steam pressure decreases, temp decreases, entropy increases, enthalpy decreases

Question 15

4 trips on a gas turbine

Answer 15

• overspeed trip
• low lube oil pressure
• steam supply temp and pressure trip
• excessive vibration
• high lube oil temp

Question 16

necessary safety appliances on a boiler

Answer 16

• safety valve
• flame scanners
• lwco
• high water cut out
• fuel SSOV
• tri cocks
• pressure gage
• drum vent

Question 17

What is tensile strength

Answer 17

the amount of force required to pull an object apart

Question 18

what is considered an adequate boiler purge

Answer 18

8 changes of air

Question 19

water level below the glass what should you do

Answer 19

shut off fuel and air but continue to feed boiler with water till nowl is restored

Question 20

proper viscosity when burning oil

Answer 20

100 - 150 ssu

Question 21

boiler indicators and recorders show water level stabilized just below visible range of the glass, what would you do

Answer 21

operation can be maintained providing immediate action is taken to restore the nowl. This should be done with care, caution, and understanding while using all indicators available.

Question 22

water is above the glass what what would you do

Answer 22

shut off the feedwater, fuel and air, in that order. If the water level does not recede into the visible range within 2 minutes, operate the blowdown valve to lower the level

Question 23

some causes of carry over

Answer 23

high drum level, inadequate drum internals, foaming, too small drum for proper separation

Question 24

types of non destructive testing on boilers

Answer 24

• ultrasonic
• radiographic testing (x-ray)
• dye penetrant
• magnetic particle testing
• visual examination
• eddy current
• boroscope

Question 25

most important valve on a boiler, why

Answer 25

safety valve - keeps the steam pressure in the boiler room from exceeding the boilers mawp in order to prevent an explosion

Question 26

list common chemical tests on boiler water

Answer 26

• ph
• conductivity
• alkalinity
• hardness
• phosphate
• sodium sulfite

Question 27

asme stamping

Answer 27

S- power boiler
M - miniature boiler
A - Boiler assembly
V - Safety valve
PP- Pressure piping
U - Unfired pressure vessel
E - Electric boiler
H - Low pressure heating boiler