Homework Flashcards
Charles second law
For a constant volume process, pressure increases as temp increases
Saturated steam
Temp corresponds with pressure
Superheated steam
Temp above corresponding pressure
Charles first law
For a constant pressure process, volume increases as temp increases
Boyles law
Constant temp process, change in pressure causes opposite change in volume
Solid and hollow Staybolts
Hold inner and outer wrapper sheets together. 3/16” telltale hole
Girder stay
Used on crown sheet of scotch marine
Radial stay
Superseded girder stay, more flexible and hold less scale.
Diagonal stay
Above tubes to stay flat portions of heads not supported by tubes
Caustic embrittlement
High alkaline material leads to breakdown and weakening of boiler metal
Dog stay
Used on man and hand holes
Solid through stays
Holds rear and front tube sheets. Nuts on inside and outside of boiler drum
Float feedwater regulator
Float operates off water level and moves a mercury switch
Bhp
33475 btus
One vertical foot water column
.433
Water column pipe requirements
Minimum 1” pipe. 3/4” blowdown.
0-250F cast iron
251-350 malleable iron
351+ steel
Thermodynamic steam trap
Single moving disk. Steam pushes disk down to close discharge and condensate pushes disk up to open.
Blowdown pipe requirements
1” minimum 2.5” max.
Boilers over 100psi require two
How many turns to open slow opening valve
5
Carryover
Small amount of water enters header
Priming
Large amount of water enters header
Hp
33000 ftlbs/min
Float thermostatic steam trap
Ball and float. Rises with condensate level. Thermostatic element opens air vent
Inverted bucket steam trap
Steam flows into an inverted bucket and holds bucket up and closes discharge. When condenses bucket falls and opens discharge.
Blowdown or blowback
Drop in pressure that closes safety valve. Normally 2 to 8 lbs below popping pressure but not more than 4%
When are extra heavy blowdown pipes needed?
Above 125psi
Safety valve pipe requirements
3/4” minimum and 4 1/2” max pipe size
Impulse steam trap
Works on pressure differential
Thermostatic steam trap
Bellows filled with fluid that expands and contracts
Safety valve relieving capability
Must relieve enough pressure to allow boiler to not exceed 6% of the mawp
Hydrostatic test
Pressure brought up to 1.5 times the mawp. Water temp at least 70F
Thermoexpansion feedwater regulator
Thermostat attached to mechanical linkage.
Thermohydraulic feedwater regulator
Tube within a tube. Inner tube connected to water and steam side of boiler. Outer tube filled with distiller water and connected to bellows and valve.
MAWP=
Tensile strength x metal thickness x joint eff. / safety factor x radius of drum in inches
Two or more safety valves needed if
Over 500 sqft heating surface equipped with superheaters one is not of sufficient capacity or if mawp is lowered by inspector
1 gallon of water=lbs
8.33 lbs
1 gallon = cubic inches
231
A therm =
100,000 btu
Matt
Mixture atomization temp time. All needed for complete combustion
Gpms of recip pump
Lane/231
Bituminous coal
Soft coal high volatile matter
Pressure atomizing burner
Fuel oil burner atomizes fuel without using steam or air. Uses mechanical. Tip and plate.
Sulfur dioxide
Byproduct of high sulfur content coal.
Specific gravity
Ratio of any volume of fuel oil @ 60F to the weight of any equal volume of water @ 60F. Measured by a hydrometer.
Stoker
Mechanical coal feeder
Ultimate analysis
NOCASH
Pressure reducing governor
Low pressure gas systems. Reduces to 0lbs
Carbon dioxide
Co2. Not so bad. What plants breath. Byproduct of complete combustion
Carbon monoxide
Co. Byproduct of incomplete combustion. Very bad. Not all fuel burned
Steam atomizing burner
Uses steam at a pressure above 20psi or higher to atomize fuel
1” mecury = psi
.491
Anthracite coal
Hard coal very high carbon content
