"A" Test - 1st Grade Stationary Engineer Flashcards
(179 cards)
1
Q
How is the head of a B&W boiler stayed?
A
The heads are bulged and there is no need for stays.
2
Q
Which tubes on a sterling boiler are beaded?
A
Every other tube in the bottom row of the top drums for drainage, every other tube in the top of the mud drum. This prevents air pockets from forming.
3
Q
When installing a tube in a tube sheet how much of the tube should stick out pass the tube sheet?
A
T = thickness of the tube,
No more than 2T and no less than 1T and
no less than 1/8” or more than ¼”.
The question above might be worded differently on the test.
4
Q
Why are the tubes on a Stirling boiler bent?
A
They are bent so they enter the drum radically; this allows the tubes to be properly expanded into the drum and improves circulation.
5
Q
How much total pressure is on the face of a drum that is 36” in diameter with a gauge pressure of 125 lbs psi?
A
Dia X Dia X .7854 X Pressure = Total lbs. Pressure.
36 X 36 X .7854 X 125 = 127,235 lbs. total pressure.
6
Q
What is caulked on a boiler and what happens if the caulking fails?
A
A riveted joint inside the drum is caulked by using a blunt tipped chisel to drive the metal of the joint tight against the drum; it prevents boiler water from entering the joint and deteriorating it.
7
Q
What is meant by flash point, ignition (fire) point, and pour point?
A
Flash point is a temperature when a substance gives off a vapor that flashes when exposed to flame; Ignition point is a temperature when a substance gives off a vapor that will burn continually. Pour point is the lowest temperature it will flow as liquid.
8
Q
What is an orsat apparatus? Where is it used? Why is it used?
A
It is a flue gas analyzer that measures the percentage of carbon dioxide, oxygen and carbon monoxide in the gasses of combustion. It is placed in the breeching. It determines combustion efficiency.
9
Q
Explain how you would replace a boiler grate with a chain grate stoker and what changes would have to be made?
A
When installing a chain grate stoker in an existing boiler, the boiler will have to be raised or the stoker pitted so as to maintain the proper furnace volume between the stoker and boiler.
10
Q
In flue gas what does carbon monoxide indicate?
A
Presence of carbon monoxide indicates incomplete combustion.
11
Q
How much heat is lost when 1 lb. of carbon is burned to CO? – CO2?
A
Carbon burned to CO2 – subtracted from – Carbon burned to CO
14,540 BTU’s/lb. - 4,380 BTU’s/lb. = 10,160 BTU/lost
12
Q
How many lbs. of air are required to burn 1 lb. of carbon?
A
Air is 23.15% O2 by weight.
Find how much air it takes to yield 1 lb. of O2
1/.2315 = 4.319 lbs. Air to yield 1 lb. of O2
1 lb. Carbon requires 2.67 lbs. O2 to burn completely
4.319 X 2.67 = 11.53 lbs. of air.
13
Q
What useful purpose is nitrogen in a boiler?
A
In dry storage, nitrogen is used on the water-side.
In the fire nitrogen will control the burn ratio of fuel in the furnace.
14
Q
Is each pass of the boiler larger or smaller and why?
A
Each pass is smaller than the one before it, as the gasses cool by contact and have less volume.
15
Q
If you used 3 ton of coal in an 8 hour shift and averaged 150 Boiler HP what was the rate of evaporation?
A
One boiler HP = 34.5 lbs. of steam per hour
34.5 X 150 BHP X 8 hr. = 41,400 lbs. of steam an hour.
16
Q
What devices are in the fuel oil train to the boiler?
A
Thermometer, shut off valve, vacuum gauge, check valve, priming tee, duplex strainers, pumps, relief valve, isolation valves, pressure gauges, prv, metering valve, solenoid valves, oil heaters, nozzles.
THE QUESTION IS WHAT ARE THE (SIX???) SAFETY DEVICES ON FUEL OIL TRAIN TO THE BOILER?
17
Q
How do you increase the draft of the stack?
A
By increasing the height of the stack, or by adding mechanical draft.
18
Q
Draw or explain connecting a safety valve.
A
Independent of any other steam connection,
As close as possible to the boiler without any unnecessary piping or fittings,
It shall be screwed or fastened to the boiler shell,
It shall stand upright,
And the vent piping should be securely fastened to the building and not rigidly connected to the valve.
19
Q
How do you regulate the blow-down of a safety valve?
A
It can be done only by a licensed person; they would adjust the blow back ring, the spring tension or both about 10% for pressures up to 250 psi.
LOTS OF QUESTIONS ABOUT BLOW-DOWN, this might be one of them
20
Q
When is it compulsory to use at least two safety valves on a boiler?
A
When heating surface is more than 500 sq.ft. or over 4,000 lbs. per hour steam generating capacity.
21
Q
What effect does soot have on the heating surfaces?
A
Soot acts like an insulator reducing the heat transfer and interfering with the draft, lowering efficiency.
22
Q
How do you start a boiler with a copes feed water regulator on it, and explain?
A
Hand feed the boiler from another source until the boiler comes up and is on line, it is a heat activated device and will not operate until the boiler is up to pressure.
23
Q
Name three factors that cause scale?
A
High conductivity, high hardness, poor water treatment.
24
Q
How is hardness in boiler water usually measured?
A
Parts per million (ppm) of calcium and magnesium in solution.
25
Give three reasons to treat boiler water.
Reduces scale, prevents foaming and priming, and reduces corrosion and improves efficiency.
26
What are Amines and name two types?
Boiler chemicals that evaporate and go out with the steam to keep condensate PH above acid, Low pressure and high pressure Amines.
27
What if your condensate return had a PH of 6.5, what should it be?
It would be acidic; it should be 8.0 to 8.5.
28
What are phosphates?
Phosphates are an internal boiler water treatment used to precipitate solids as sludge.
29
What is chelant?
An internal boiler water treatment used to hold solids in suspension.
30
When doing a wet lay up of a boiler how full do you fill the boiler and what chemicals do you add and to what ppm?
Fill all the way to the top with deaerated water; add caustic soda to 450 ppm to maintain ph and sodium sulfites (oxygen scavenger) to 250 ppm.
31
What is the return condensate percentage in feed water if the make up conductivity is 836 mho and the feed water is 172 mho, condensate conductivity is 60 mho?
-172 = 664
-60 = 776
664 / 776 = .85567%
Makeup 836 mho
Condensate 60 mho -> [feed water] ---- Feed water 172 mho
{Boiler}
32
Explain the operation of a zoelite water softener?
Back was cycle agitates and washes away calcium and magnesium ions as soluble chlorides and the resin beads are coated with sodium ions.
Rinse cycle removes excess of brine from the beads. During use the resin gives up the sodium ions to attract the calcium and magnesium ions.
33
What are the essential steps in putting a cold boiler on line with other operating boilers?
Blow down gauge glasses and water column
Check the operation of feed water valves and pump.
Open vent to boiler drum.
Start the burner on low manual fire.
Test the flame scanner.
Test the low water cut off.
When the boiler pressure starts to build close vent.
Open header valve and non-return valve drains.
Open the equalizing lines around the header valve to warm the boiler.
When the boiler pressure is 80% of the header pressure open header valve and close drain.
Unscrew the had wheel on the non-return valve and close drain.
When the boiler pressure equals header pressure put control in auto.
34
WHEN DO YOU BLOW DOWN THE GAUGE GLASS?
To ensure the gauge glass measurement continues to be accurate, a blowdown occurs at scheduled intervals (daily or weekly etc.). The main purpose of a blowdown is to remove any blockage within the water or steam pipework that connects the boiler to the gauge glass.
35
What steps are taken when performing Lock-out and Tag-out?
Notify all persons affected by shut down.
Stop the equipment, remove all power sources, release any stored electrical, pressurized or fluid energy.
Apply lock-out, Tag-out procedures.
Verify all electrical has been de-energized and all controls are in the off position.
36
What steps must be taken to return locked and tagged equipment to service?
Remove all tools, release secured moving parts, prepare equipment for operation.
Make sure affected personnel are clear of equipment.
Replace all safety guards and controls.
Remove Lock-out and Tag-out.
Energize and test equipment.
37
What is a confined space?
It is a space large enough to physically enter and exit and is not designed for continued occupancy.
38
How high will the suction of a single stage centrifugal pump lift water?
Cold water, 10 to 15 feet.
39
Describe the operation of the centrifugal pump.
The spinning impeller draws liquids into its center, and discharges it from its outer edge into a spiral casing, the velocity of the liquid is changed to pressure head.
40
How is the discharge pressure of a stage of a centrifugal pump determined?
It is the calculation of impeller size. Impeller speed, friction losses and the size of the suction and discharge.
41
How would you change the discharge pressure of a single stage centrifugal pump?
Install a PRV, change the speed, throttle the discharge, trim the impeller.
42
What will happen to the discharge pressure of a centrifugal pump if the discharge valve is closed completely?
The pressure will usually increase and then level off.
LOTS OF QUESTIONS ABOUT CENTRIFUGAL PUMP, THIS MIGHT BE ONE OF THEM.
43
What type of pump is used for 250 to 300 PSI or more?
Multi-stage centrifugal pump.
44
Describe a motor driven rotary pump.
It is a positive displacement pump. It has rotating shaft or shafts with rotors consisting of gears, vanes, lobes, cams, screws, operating in a close fitting casing. They do not use valves in their design and they operate efficiently on both low & high viscosity liquids with a low NPSH requirement.
45
Give seven advantages of a rotary pump.
Self priming
Low NPSH requirements
Can handle high viscosity liquids at a high efficiency
Wide speed range
Are available for low capacity, high head or high capacity applications.
Capable of high suction lifts
Slip is low
46
What will happen if the discharge valve is closed on a rotary pump?
The relief valve would open protection the pump from damage.
47
How high will a rotary pump lift water?
??
48
What is a nozzle, and name two types?
A nozzle is a small opening which converts steam pressure into velocity. Two types, Convergent and divergent
49
How does a nozzle work?
Steam issuing from a nozzle attains a high velocity with a pressure drop, velocity energy is then converted into mechanical energy by the steam moving in the turbine.
50
What is the pressure stage, velocity staging and what is the difference?
Pressure stage allows only a limited pressure drop in one set of nozzles. Velocity staging is applying velocity energy in the steam coming from the nozzles to two or more sets of moving blades, with the pressure drop occurring in the stationary blades. The difference is where the pressure drops occur.
51
What is the difference between an impulse and a reaction turbine, name four types?
The impulse turbine is designed so the expansion of the steam occurs almost entirely in its stationary blades, and there is almost no pressure difference of the steam entering and leaving the stages.
Types of Impulse: Re-entry flow, rotor, vertical, horizontal, de Laval Wilkinson, Zoelly, Pelton.
The reaction turbine is designed so there is considerable expansion in the rotating blades and there is a pressure difference of the steam entering and leaving the stages.
Types of Reaction: Tamden, Cross compound, single flow, double flow, Parsons, Allis chambers, Ingersal Rand.
52
What conditions are reaction turbines best suited?
They are made for all steam conditions, but generally designed to operate on low pressure exhausting into a condenser.
LOTS OF QUESTIONS ABOUT TURBINE PUMPS, THIS MIGHT BE ONE OF THEM.
53
What forms of energy losses are in a turbine?
Steam leakage friction between stages, Eddy friction losses, Windage friction, Radiation, Mechanical friction, Steam velocity losses from last stages to condenser.
LOTS OF QUESTIONS ABOUT TURBINE, THIS MIGHT BE ONE OF THEM.
54
How is the speed of the turbine regulated?
By a governor, used to maintain turbine speed.
55
What is meant by critical speed of the turbine shaft?
A specific speed at which the shaft vibrates most violently.
LOTS OF QUESTIONS ABOUT TURBINE, THIS MIGHT BE ONE OF THEM.
56
Define over speed?
It could be a safety trip device, or a speed in excess of its design, such as, a turbine is 10%
57
What is the function of an over speed governor?
To shut down the turbine at 10% over speed.
58
Can a turbine be run without a governor?
Yes, those on large ships that drive the screws, may be found without a governor.
59
What is a diaphragm, and where is it located?
It is a complete set of nozzles in one stage of a turbine that is built into the steam chest.
This question was worded differently on the test.
60
What is seal stripping?
These are sealing strips between turbines stages to reduce leakage between stages.
The test asked what is used to prevent leakage between stages of the turbine?
61
What is a dummy packing, dummy piston and where are they located?
A dummy packing is part of a labyrinth sealing device on a dummy piston. The dummy or balanced piston is a large disk that is part of the rotor, arranged to have a different pressure on each side creating a thrust action toward the high pressure side, balancing the end thrust. It is located between the impulse and the low pressure section.
The test asked what is a dummy piston?
62
How are turbine bearing lubricated? What are two main qualities?
Gravity circulation: Oil rings lifting oil to the bearing.
Pressure system: Circulating oil to the bearing.
Two main qualities are correct viscosity and resistance to emulsification.
63
What is the highest temperature allowed for turbine bearings?
150ºF
THIS QUESTION IS GOOD TO KNOW, IT’LL HELP ANSWER TURBINE QUESTIONS.
64
What is the lowest flash point for oil used in a turbine?
325ºF
THIS QUESTION IS GOOD TO KNOW, IT’LL HELP ANSWER TURBINE QUESTIONS.
65
What is a Jet condenser? A barometric condenser? A water-leg condenser?
In a Jet condenser, water comes down from high pressure jets meeting the steam that enters on the side, together they drop into the hot well, which overflows by gravity, permitting non-condensable to escape. Two types are low level jet and a barometric jet.
The barometric condenser is a condenser with a 34 foot plus tail piece. The weight of the water falling down the long tail piece draws a vacuum, reducing back pressure on the engine or turbine, increasing its efficiency.
A water-leg condenser is a naval name for a barometric condenser, it has a 34 foot plus tail piece. The weight of the water falling down the long tail piece draws a vacuum, reducing back pressure on the engine or turbine increasing its efficiency.
The test asked what are the other types of condensers.
66
What is an air ejector, and what is it used for?
A device using a jet of air or steam across a suction chamber into a venture, it is used to prime pumps, remove non-condensables from condensers or draw an initial condenser vacuum when starting a turbine.
67
Explain how a disk flow condenser works.
Cooling water enters the top, cascading down over the disks. Exhaust steam entering from the side condenses when cooled by the water. Condensate and cooling water flow down the 35’ tail pipe into the hot well.
Non-condensables are removed by a two stage ejector located in a vent condenser at the same height.
68
What is a Vent condenser.
A small condenser located on the vent of a larger condenser pulling off air and vapor, to discard the air to the atmosphere, and the vapor is condensed and flows to the hot well.
69
How many gallons of water will a cooling tower evaporate per ton of refrigeration, knowing that 1,000 BTU’s are needed evaporate 1 lb. of water in the tower?
1 ton of refrigeration = 288,000 BTU’s in a 24 hour period
BTU’s per ton of refrigeration / (rated BTU’s /lb. X lbs./gal)
288,000 (1,000 8.3 = 8,300)
288,000/8,300 = 34.69 gallons per ton.
70
Define Extraction or Bleeder turbine, Double flow turbine and Semi double flow turbine.
In the extraction type, openings are provided in the turbine casing for extraction of the steam, for heating feed water or other purposes.
In the double flow, steam enters the center of the turbine and flows both directions parallel to the shaft, balancing the end thrust.
In the Semi double flow, steam enters the turbine passing through one set of blades, then is divided flowing both directions parallel to the shaft, reducing end thrust.
The test asked “What is a double flow turbine?”
71
What is the difference between a bleeder turbine and a mixed pressure turbine?
The bleeder turbine allows for the extraction of steam at various pressures, from the turbine for other processes.
The Mixed pressure turbine admits steam of various pressures into the turbine.
72
What is a reduction gear?
Because turbines run at high shaft speeds, speed reduction gears are sometimes needed to achieve a usable end speed.
73
Why is superheated steam used in turbines?
It will do more work, less wear, less friction, less maintenance.
74
What do you check on a turbine hourly, monthly, yearly?
Hourly: Oil pressure and temperature, bearings, cooler, steam pressure and temperature, gpm., the load and abnormal noise.
Monthly: Check oil for water and sludge, check oil strainer, check governor, over speed trip, vacuum breakers, condensers.
Yearly: Dismantle and check for corrosion, wear dirt and scale, oil and steam passages, eroded blading and all valve seats, lubrication system, governor parts, bearings, vacuum pumps, ejector, air leaks.
75
What is the difference between an open feed water heater and a D.A. tank?
The original type open feed water heater operates near atmospheric pressure, simply heating the feed water. The deaerators will operate from 5psi to 15 psi heating the water hotter and has a vent condenser which removes O2 and CO2 from the water.
76
When installing a steam header what factors must be taken into consideration?
You must consider adequate support for expansion and contraction, operating pressure, velocity and pressure drop, insulation, valve location, trap location, flow of condensate.
77
If you have to connect a common header to the piping listed, what would be the size of the header? 10-1/2” lines, 12-3/4” lines and 2- 4” lines.
10 – ½” lines .5 X .5 X .7854 X 10 = 1.9635
12 – ¾” lines .75 X .75 X .7854 X 12 = 5.3
2 – 4” lines 4 X 4 X .7854 X 2 = 25.133
Added together = 32.397 and √ is 5.692
Next closest size would be 6”
78
Name the methods of joining high pressure steam lines?
Butt welds, or weld flanges.
THES TEST ASKED TO NAME FOUR METHODS OF WELDING IN THE INDUSTRY.
79
What are two types of welds on boiler construction and repair?
(SAW) Submerged Arc Welding; (OAW) Oxyacetylene Welding; (SMAW) Shielded Metal Arc Welding
flux cored arc welding (FCAW)
80
If you have a 100ft. steam line carrying 150 lbs steam pressure in a 70ºF room, how much room is needed for expansion? And what if you had 5 lbs of steam?
In the test, they will give you all the information in order to figure out the answer so remember the formula. ACTUAL QUESTION IS 200FT, 150LBS, 90 DEGREES
Final temp – initial temp X length X inches X coefficiency of expansion/inches/degree for steel.
Expansion with 150 lbs steam
366ºF – 70º F X 100 X 12” X .00000734 = 2,607”
Final temp – Initial temp X length X inches X coeffic/expan/inch/degree
Expansion with 51 lbs of steam
227ºF – 70ºF X 100 X12” X .00000734 = 1.383”
Final temp – Initial temp X length X inches X coeff/expan/inch/degree
81
List six qualities of lubrication oil.
Filterability, Low viscosity, hold up under heat, good cooling properties, low acid, acts as a good moisture barrier.
The test asked to list four qualities of turbine oil and why?
82
Define units of vacuum and how do they relate to PSI?
Vacuum is measured in inches of mercury. One inch of mercury is equal to .4912 PSI.
83
Define hygrometer.
A hygrometer is a device used to measure the relative humidity in the air.
84
Describe a sling psychrometer and how to use it.
It determines relative humidity. To operate, moisten the wick on the wet bulb and whirl, when the mercury stops dropping, read both thermometers. A comparison of the two temperatures on the psychrometric chart shows relative humidity.
85
What is the correct relative humidity for a office building?
45% to 50% relative humidity.
86
If a boiler HP is equal to 34.5 lbs. of steam per hour and from and at 212ºF, how many BTU’s are equal to a boiler HP?
34.5 X 970.3 BTU’s = 33,475.35 BTU’s/hp
THIS QUESTION MIGHT HAVE BEEN ON THE TEST.
87
Define relative humidity.
The percentage of moisture contained in air as compared to the amount of moisture the air could contain at that temperature.
88
How many BTU’s must be removed from one tone of 80 o F water to make one tone of ice, allowing for 20% loss?
Initial Final Latent heat
Temp -temp +fusion X one ton add the loss = total BTU’s
80 -32 +144 X 2000 = 384,000 X 1.20 = 460,800
89
How do you test for leaks in a ammonia system?
Sulfur sticks, Phenolphthalein, Foams and Litmus paper.
90
What is a congealing tank?
A congealing tank is a brine tank in which the brine is frozen during off peak hours. Because more of the heat is removed from the brine, the system can handle high peak loads with a more uniform temperature.
91
What is a brine holdover in ammonia?
Holdover plates are stainless steel tanks which contain an evaporator coil surrounded by a liquid solution. As the compressor runs, this solution freezes. Once the compressor turns off, the frozen solution continues to absorb heat from the refrigerated box thereby extending the "off" cycle of the compressor. When incorporated into a properly designed system, holdover plates can significantly reduce average energy consumption.
https://www.rparts.com/index.php?rt=core/index&cPath=84_13_20
92
What is a King valve?
It is located on the outlet of a receiver or branch line and used to confine the refrigerant so repairs can be made on the system.
93
On an enclosed compressor how is ammonia removed from the crank case?
A by-pass line is installed from the crank case to the suction line.
94
How do you pack an expansion valve (ammonia)?
Wear protective gear, back seat the valve and replace packing, if you can not back seat the valve you will have to close the king valve and pump down the system to repack.
95
How do you know if the system needs ammonia?
Compressor constantly running, system not cooling, low delta T across the compressor, short cycling, etc.
96
Explain the purpose of the accumulator and how it works.
It is a safety device that prevents the compressor from slugs of refrigerant, it is placed in the suction line, so any liquid that flows into the accumulator will be evaporated before entering the compressor.
97
What is a purger and where is it located on a refrigeration system?
A device used to remove air and non-condensables gases from the system, located at the highest point in the system.
98
What is a shell cooler?
It is a tube and shell heat exchanger with the liquid being cooled in the tubes surrounded by ammonia, or ammonia in the tubes surrounded by the liquid being cooled.
99
Describe an evaporative condenser.
It has refrigerant in it’s condenser coils, inside a induced draft cooling tower using evaporation to remove most of the heat from the coils.
100
How does a Lithium bromide system work?
There are four main parts in the cycle.
generator
condenser
evaporator
absorber
The entire system operates in a near perfect vacuum, using water as a refrigerant and bromide as a absorber.
Heat in the generator section evaporates the water away from the bromide. The bromide flows back to the absorber and the water vapor is condensed in the condenser, then sprayed over the coils in the evaporator, where it again evaporates before being absorbed by the bromide in the absorber section. As the water evaporates it pulls heat from the water or air to be cooled. The bromide/water solution is returned to the generator by a pump which maintains the pressure difference in the system.
101
WHAT ARE THE FIVE RESPONSIBILITIES OF THE EPA?
102
How often are M.S.D.S. sheets inventoried?
In accordance with individual corporate polices MSDS sheets and records of employee exposure must be kept on file for 30 years.
103
Explain the N.F.P.A. hazard labeling.
The colors and numbers indicate the hazard and the degree of severity
Blue is Health
Red is Fire
Yellow is Reactivity
White is properties and hazards of particular materials.
A number indicates the degree of severity, Highest is 4 hazard down to a 0 hazard.
104
What is the E.P.A.?
Environmental Protection Agency, is a federal agency set up to control and debate pollution in the areas of air, water, solid waste, pesticides, radiation and toxic substances.
105
E.P.A. requires what records to be kept regarding underground fuel tanks?
Upon request you must provide to EPA records on installation, monitoring, cathodic protection, release detection equipment calibration, maintenance repairs and closures.
106
What spill protection is required on fuel tanks?
That there must be catchment basin with a fill opening with a capacity of 5 to 25 gallons.
107
List three over fill preventions required on a fuel oil tank.
Automatic shut off devices on the fill, overfill and high level – audible alarms, ball float valves on the vent.
108
How often do you check a rectifier on a fuel tank? Who can check it? What do you check?
You must inspect it every 60 days and keep records of three readings on file. A qualified cathodic protection inspector would check the D.C. output. If testing a rectifier, it must be done after six months of installation and every 3 years after.
109
Who can inspect and repair your UST leak detection and overfill protection systems and list six things to log on the report?
A qualified UST inspector/contractor, six things on the report are: Identify equipment, release detection, suspect or confirmed releases, spill and overfill protection, corrosion protection and records kept, walk through inspection.
110
What is a motor?
A device that converts electrical energy into mechanical energy.
111
What are slip ring motors used for?
They are used where the starting current of the equipment, starting under full load would be excessive, examples are compressors, loaded conveyors, hoists, pumps, mixers, grinders and equipment using large amounts of starting amps.
112
What is a power factor?
The ratio between the apparent power and the actual power in a AC circuit.
113
Define torque.
A mechanical twisting force producing rotation, measured in foot lbs.
114
Define Dynamo.
A machine used to convert mechanical energy into electrical energy and electrical energy to mechanical energy.
115
Name the components of the magnetic circuit of the dynamo.
Field coils, air space, poles and rotors.
116
What is a generator?
A device to convert mechanical energy into electrical energy.
117
Does an AC alternator or generator require DC voltage?
Yes, the DC voltage is required to make the magnetic field.
118
Define cycle.
One complete positive and negative alternation of a wave form in a AC circuit.
119
Define frequency.
The number of occurrences in a unit of time, such as the voltage in an A.C. circuit.
120
How is frequency controlled in an alternator?
By changing the rotating speed of an alternator and the number of poles.
121
How is voltage controlled in an alternator?
By changing the rotating speed of the D.C. exciter generator.
122
What is a 3 Phase Y connected alternator?
It has three windings, 120 degrees apart in phase relationship, connected in a Y shape. The middle point of the Y is common connection of one end of each winding. The other end of each winding is a line connection. The middle point of the Y may or may not be brought out as another line connection.
123
What is the main difference between an A.C. generator and a D.C. generator?
In the A.C. generator the magnetic field is produced on the rotor, and in a D.C. generator the magnetic field is produced in the stationary coils.
124
What is demineralization?
An ion exchange process using strong acids and bases, in the regeneration used for high-pressure boilers.
125
Condensate polishing?
High pressure systems use an ion exchange system that can withstand high temperatures to purify condensate before it returns to the boiler.
126
What is the cycle of concentration in the boiler, if there is 180 PPM chloride in the boiler water and 18 PPM in the feed water?
180 / 18 = 10
127
What is a surge tank?
A storage tank holding a reserve of feedwater for whenever boiler demands are more than the deaerators can keep up with.
128
Alloy, what is it?
A mixture of two or more metals blended together. Steel and brass are two types.
129
What is a push nipple?
Holds a sectional boiler together.
"The push nipple serves as a connector between sections of the boiler, facilitating the efficient transfer of heat and steam. Its design allows for easy installation and secure fit, contributing to the overall efficiency and safety of the boiler system. The product dimensions are industry-standard, ensuring compatibility with CT and F series boilers from Velocity Boiler Works."
https://libertysupply.com/products/lsi89q8xai#:~:text=The%20push%20nipple%20serves%20as,safety%20of%20the%20boiler%20system.
130
Water column piping, maximum and minimum Dia?
Minimum 1”, Maximum 2 ½”, blow off line ¾”
This question was worded differently in the test.
131
Flexible coupling?
Quiet, less wear, easily aligned.
132
Sodium sulfite?
Boiler D.A. chemical treatment, (Oxygen scavenger).
133
Combustion?
A chemical reaction between oxygen and combustibles, a process of rapid oxidation by which heat energy stored in fuel is liberated.
This is the first question on the "A" Test.
134
Tube ligaments?
It is the area of metal in the tube sheet between the tubes.
135
HRT how is it supported? Why?
Supported by saddles and rollers or suspended on hangers supported by over head beams to permit movement of the boiler as it expands and contracts.
136
HRT slope?
1” to 3” from front to rear for drainage and circulation.
137
Power pump?
A pump with an adjustable variable stroke and can be used in chemical feeding with a precise volume control.
138
Fire safety plan?
Goals and Priorities of the Plan
Basic awareness and appropriate response to:
Understanding what Fire is
Fire in your area, types and how to react
Fire exit drills
Locations of extinguishers, fire hoses
Escape routes and evacuation
Rescue
139
Name two types of evaporators?
In refrigeration you have Dry (droplet) type and the Flooded type.
140
Your CO2 is at 22%, what are you doing wrong or right?
Having a good % would be 12 to 15%, 20% CO2 is ideal but not practical. To maintain 22% CO2, you would have to increase you excess air which would waste heat and cool the boiler.
The question above is worded differently on the test but the answer should be the same.
141
What percent of air is oxygen by volume, by weight?
Air is 21% oxygen by volume and 23% oxygen by weight.
142
Why is HRT boiler dangerous?
Drums and joints are exposed to high heat, causing stress and unequal expansion and contraction to the tubes and boiler shell which can cause a fire side explosion.
143
Name 5 controls on a fuel train.
Soleniod valve, pressure regulating valve, temperature regulating valve, temperature cut-outs and pressure cut-outs, gauges, pumps, heaters.
144
What provisions are made on a watertube boiler with curved tubes for tube removal?
Some of the tubes are left out, tubes are staggered, and every other row is omitted.
145
What is a badge plate? Where is it located?
Locomotive steam boilers have a badge plate attached to the boiler backhead located in the cab, it displays allowed steam pressure.
146
NFPA diamond, what does Blue 1, Red 3 indicate?
Blue 1 Health hazard – slightly dangerous – breathing apparatus may be worn.
Red 3 indicates Fire hazard – flash point below 100 o F – ignites under normal temperature conditions.
147
Chief difference in design between a condensing and non-condensing high pressure turbine?
The difference between a condensing and non-condensing turbine is that a condensing turbine exhausts to some type of condenser which condenses the steam back to water for re-use in the system. This also causes the low pressure end of the turbine to be operating under a vacuum. A non-condensing turbine, sometimes called a backpressure turbine exhausts to atmosphere. The low pressure end of a non-condensing turbines will be at atmospheric pressure and above.
148
Who can make repairs on your refrigeration system?
If it is a Freon system it must be a certified technician.
149
2” pipe has a wall thickness of 3/16”. What is the inside (I D) diameter?
3/16” X 2 = 6/16” (2”) = 32/16” = 26/16” which = 1 5/8” I D
This is not a normal size pipe
150
What is excess air?
Amount of air in excess of the theoretical amount needed for complete combustion.
151
Define combustion?
A chemical reaction between oxygen and combustibles. It is the process of rapid oxidation by which the heat energy stored in fuel is liberated.
152
Define factor of safety?
A comparison of tensile strength to actual working stress – bursting pressure / working pressure.
153
What is a permit space, how does an operator know when one is needed?
A permit-required confined space is one that meets the definition of a confined space
and has one or more of these characteristics: (1) contains or has the potential to contain
a hazardous atmosphere, (2) contains a material that has the potential for engulfing an
entrant, (3) has an internal configuration that might cause an entrant to be trapped or
asphyxiated by inwardly converging walls or by a floor that slopes do
to a smaller cross section, and/or (4) contains any other recognized serious safety or
health hazards.
"Confined space" means a space that:
Is large enough and so configured that an employee can bodily enter and perform assigned work; and
(2) Has limited or restricted means for entry or exit (for example, tanks, vessels, silos, storage bins, hoppers, vaults, and pits are spaces that may have limited means of entry.); and
(3) Is not designed for continuous employee occupancy.
154
How do you determine the size of a receiver on an ammonia cooling unit for a large company?
The unit must be large enough to contain everything in the system, including the piping, and allow for 20% expansion.
155
Which way should a steam line slope and why?
Horizontal runs must slope in the direction of steam flow with steam traps at all points where water may accumulate lessens the chance of water hammer. SPO 6th 582
156
List 6 things printed on Badge Plate on a boiler?
(A) Design Steaming Rate (B) Boiler Design Pressure (C) Boiler Operating Pressure (D) Boiler Operating Temperature (E) Economizer Design Pressure (F) Economizer Design Inlet Temperature
157
How big would the blowdown tank vent line be?
It should be big enough so the tank pressure doesn't exceed 10 psi.
158
How are gasses formed in an ammonia system?
Heat is absorbed in the evaporating coil which causes the liquid to boil until vaporization is complete.
159
What valves are on the feed line to the boiler?
One feedwater regulator with 2 gate valves and a bypass globe valve, also a check valve.
160
Where are msds documents kept?
They are readily available in the areas of storage. Individual company’s intranet.
161
Who is authorized to handle refrigerant?
You must be certified to remove or add refrigerant to the system.
162
In the boiler tubes section, one question asked “Where do corrosion happen?”
Crevice corrosion can form near cracks
Galvanic corrosion can occur on the metal near a joint
Corrosion can also happen in a boiler when the pH of the water is too high or too low
163
Five advantages of fire tube boilers over water tube boilers?
less expensive to purchase
easy to clean and repair because maintenance can be performed from outside the unit rather than inside
simple construction, compact size and the ability to easily meet rapid fluctuations in steam demand
low first cost, reliability in operation, less draught required, quick response to load changes
164
Blowdown tank?
A tank used for blow-off water from the boiler, you can not directly blowoff water to sewer because steam and hot water might damage the lines. The tank has a 4” vent line to prevent back pressure. Baffles are installed, and it has a 2 ½” drain line located opposite the inlet near the tank bottom.
165
Describe Kingsbury thrust bearing.
Kingsbury is most famous for his hydrodynamic thrust bearing which uses a thin film of oil to support weights of up to 220 tons.
How Kingsbury's Thrust Bearing Works
A thrust bearing transmits axial loads to the foundation or machine support of rotating machinery.
Our equalizing thrust bearing actually transmits the load through a self-renewing film of oil during operation and a unique force-balancing action distributes the load across the shoes. Working surfaces touch each other only during start-up and shut-down. Otherwise, these surfaces are separated by the fluid film, so surface wear is minimal, and bearing life dramatically lengthened.
The Kingsbury thrust bearing offers many operating advantages, including:
Excellent shock absorbing capacity
Superior damping characteristics
Life span equal to that of the machine
Versatility in application
Performance monitoring capability
166
What blade gets best velocity; impulse or reation?
Reaction
167
How often are M.S.D.S. sheets inventoried?
Manufacturers and Suppliers: When you become newly aware of this information, you must revise the labels. Labels must happen within 6 months of acquiring the new information. Any chemical shipped after that 6-month timeframe must contain the new information. SDS should be modified in 3 months.
End-users: If you’re an end-user, you’re responsible for the latest version. And you must ensure that this information is easily accessible for your employees. Ask your supplier or the manufacturer to supply you with the latest version. Update your MSDS as soon as you receive new information.
168
The test asked about the connection of the water column.
Dealing with water column piping what is, maximum and minimum diameter?
Minimum 1”, Maximum 2 ½”, blow off line ¾”.
The water column shall be so mounted that it will maintain its correct position relative to the normal waterline under operating conditions.
The minimum size of pipes connecting the water column to a boiler shall be 1 inch. For pressures of 400 psig or over, lower water column connections to drums shall be provided with shields, sleeves or other suitable means to reduce the effect of temperature differentials in the shells or heads. Water glass fittings or gage cocks may be connected directly to the boiler.
The steam and water connections to a water column or a water gage glass shall be such that they are readily accessible for internal inspection and cleaning. Some acceptable methods of meeting this requirement are by providing a cross or fitting with a back outlet at each right-angle turn to permit inspection and cleaning in both directions, or by using pipe bends or fittings of a type which does not leave an internal shoulder or pocket in the pipe connection and with a radius of curvature which will permit the passage of a rotary cleaner. Screwed plug closures using threaded connections as allowed by Section I of the ASME Code are acceptable means of access for this inspection and cleaning. For boilers with all drum safety valves set at or above 400 psig, socket-welded plugs may be used for this purpose in lieu of screwed plugs. The water column shall be fitted with a connection for a drain cock or drain valve to install a pipe of at least 3/4 inch pipe size to the ash pit or other safe point of discharge. If the water connection to the water column has a rising bend or pocket which cannot be drained by means of the water column drain, an additional drain shall be placed on this connection in order that it may be blown off to clear any sediment from the pipe.
The design and material of a water column shall comply with the requirements of Section I of the ASME Code. Water columns made of cast-iron in accordance with SA-278 may be used for maximum boiler pressures not exceeding 250 psig. Water columns made of ductile iron in accordance with SA-395 may be used for maximum boiler pressures not exceeding 350 psig. For higher pressures, steel construction shall be used.
Shutoff valves shall not be used in the pipe connections between a boiler and a water column or between a boiler and the shutoff valves required for the gage glass, unless they are either outside-screw-and-yoke or lever-lifting type gate valves or stopcocks with lever permanently fastened thereto and marked in line with their passage, or of such other through-flow construction as to prevent stoppage by deposits of sediment, and to indicate by the position of the operating mechanisms whether they are in open or closed position; and such valves or cocks shall be locked or sealed open. Where stopcocks are used, they shall be of a type with the plug held in place by a guard or gland.
No outlet connections, except for control devices (such as damper regulators and feed water regulators), drains, steam gages, or apparatus of such form as does not permit the escape of an appreciable amount of steam or water there from shall be placed on the pipes connecting a water column or gage glass to a boiler.
https://casetext.com/regulation/louisiana-administrative-code/title-55-public-safety/part-v-fire-protection/chapter-50-boiler-construction-maintenance-inspection-and-general-use/subchapter-c-existing-installations-power-boilers/section-v-5028-water-columns
169
How do you know how far the tube sheets is good?
???
170
What is current and amps measured in? How is ammeter connected?
Current is measured in amperes (A) or “amps”.
Voltage is measured in volts (V).
Ammeter is always connected in series and Voltmeter is always connected in parallel in an electric circuit.
171
Question about how many blow offs are needed in a 150 psi tank?
Number of blowoff valves:
Every steam boiler shall be equipped with a quick-opening blowoff valve. Steam boilers with an allowable working pressure in excess of 100 psi shall include a second valve; the valve closest to the boiler shall be quick-acting; the second valve shall be slow-acting. The valve(s) shall be installed in the opening provided on the boiler. The minimum size of the valve or valves shall be specified in accordance with Sections I and IV the ASME Code.
172
Types of Condensers:
In industrial refrigeration, condensers are a key component of the refrigeration system as they help in removing heat from the refrigerant. There are three types of condensers that are predominantly used in industrial refrigeration - air-cooled, water-cooled, and evaporative.
Air-cooled condensers are the most commonly used type of condenser in industrial refrigeration systems. These condensers utilize ambient air to cool the refrigerant, which passes through a series of fins and tubes, allowing for the transfer of heat from the refrigerant to the air. They are relatively low maintenance, but the efficiency of air-cooled condensers can be impacted by factors such as high ambient temperatures, lack of airflow, and humidity levels.
Water-cooled condensers, on the other hand, use water as a coolant. The refrigerant passes through a tube, which is immersed in a water bath. As the refrigerant flows through the tube, heat is extracted from it and transferred to the water. This type of condenser is more efficient than air-cooled condensers, but it requires a constant water supply and can be costlier to install and maintain.
Lastly, there are evaporative condensers. These systems use a combination of water and air to cool the refrigerant. Water is sprayed onto a heat exchange coil, which cools as a result of the evaporative cooling process. The air then passes over the coil, transferring heat from the refrigerant to the air, before being discharged back into the atmosphere. This type of condenser is highly efficient and consumes less energy than air-cooled or water-cooled condensers, but they require a constant supply of water and may not be suitable for all environments.
173
Types of Steam Condensers
The steam condensers are broadly classified into two types:
Surface condensers (or non-mixing type condensers). In surface condensers, there is no direct contact between the exhaust steam and the cooling water.
Jet condensers (or mixing type condensers). In jet condensers, there is direct contact between the exhaust steam and cooling water.
Surface Condenser
The surface condenser is designed to condense and deaerate the exhaust steam from the main turbine and provide a heat sink for the turbine bypass system. In surface condensers, there is no direct contact between the exhaust steam and the cooling water. The exhausted steam from the LP turbines is condensed by passing over tubes containing water from the cooling system. The steam condenses when it comes in contact with the cold surface of the tubes and due to the heat transfer to cooling water by conduction and convection. These tubes are usually made of stainless steel, copper alloys, or titanium, depending on several selection criteria (such as thermal conductivity or corrosion resistance). Titanium condenser tubes are usually the best technical choice. However, titanium is a very expensive material, and the use of titanium condenser tubes is associated with very high initial costs. In general, there are two types of surface condensers:
water-cooled surface condenser
air-cooled surface condenser
An air-cooled condenser can be used in thermal power plants, where cooling water is in short supply. However, an air-cooled condenser is significantly more expensive and cannot achieve as low a steam turbine exhaust pressure (and temperature) as a water-cooled surface condenser.
The water gets warmed in the condenser is discharged into the cooling system (i.e., cooling tower, river, sea, or cooling pond). The condensate collected from these condensers is reused as feedwater in the boiler. Since the cooling water and steam do not mix, the condensate is recovered, and any kind of cooling water can be used. In comparison to jet condensers, in surface condensers, a high vacuum can be maintained. Therefore, we can achieve therefore greater thermal efficiency. On the other hand, surface condensers are bulky, require a large area, and have high capital costs. But these capital costs can be recovered by the improved thermal efficiency (i.e., higher )saving in running costs.
Thus, these condensers are most suitable for modern thermal power plants. These are generally used where a large quantity of inferior water is available, and better quality of feedwater is to be supplied to the boiler.
Jet Condenser
The cooling water is sprayed on the exhaust steam in jet condensers, and there is direct contact between the exhaust steam and cooling water. The condensation process is very fast and efficient, but here cooling water and condensed steam are mixed up. The condensate then cannot be reused as feedwater to the boilers. The temperature of the condensate is the same as that of the cooling water leaving the condenser. Due to the more intimate mixing of steam and cooling water, the jet condenser requires less quantity of cooling water for the condensation of steam. In general, jet condensers require less building space, and they are simpler in construction and lower in capital cost. Despite these advantages, jet condensers are not usual in thermal power plants, especially due to the loss of condensate.
174
What is a therm?
“Therm is the unit of measurement for your natural gas use over time.” One therm is equal to 100,000 BTUs (British Thermal Unit) — is the quantity of heat that’s needed to raise the temperature of one pound of water by one degree Fahrenheit.
One therm is equal to 100 cubic feet of natural gas (CCF).
Btu: (British Thermal Unit) is the amount of heat it takes to raise 1 pound of water from about 39°F to 40°F
Therm: 1 therm equals 100,000 Btu
CCF: Exactly 100 cubic feet of natural gas
MCF: Exactly 1,000 cubic feet of natural gas, or 10 CCF
175
What is the lowest condensate pH that it should be?
What if your condensate return had a PH of 6.5, what should it be?
It would be acidic; it should be 8.0 to 8.5.
176
Convert 15 degrees Celsius and show work.
(9/5 x 15C) + 32 =
(9/5 x 15/1) + 32 =
(9 x 3) = 27
(27) + 32 = 59 degrees Fahrenheit
Remember the formula, they asked to convert 122 F to Celsius.
177
Why is hollow tubes stronger than solid tubes?
When two identical rods are heated to the same range of temperature, solid rod will expand more because more heat is present in solid rod.
Strength to weight ratio is better for a hollow pipe than a solid rod. This means a hollow cylinder is stronger than a rod of equal mass and the same material. A hollow cylinder with a bigger inside diameter is better.
The torque required to produce a given twist in a hollow cylinder is greater than that required to twist a solid cylinder of the same size and material.
A hollow rod has larger moment of inertia and would be stronger in bending.
178
Draw a one pump, and a two pump feed water system.
Draw a Psychrometric chart with dew point.
Draw a Fire Safety Plan of your plant.
179
Sketch a steam header valve arrangement.
Steam off-takes
Having considered the general arrangement of the steam header, the following conditions need to be ensured:
That dry steam is exported to the plant.
That the warm-up operation is properly controlled.
That steam is properly distributed to the plant.
That one boiler cannot accidentally pressurise another.
https://www.spiraxsarco.com/learn-about-steam/the-boiler-house/steam-headers-and-off-takes?sc_lang=en-GB
Draw boiler, non return valves with drains, then header
