1st Grade A Test

Question 1

Why are the tubes on a Stirling boiler bent?

Answer 1

They are bent so they enter the drum radically; this allows the tubes to be properly expanded into the drum and improves circulation.

Question 2

Is each pass of the boiler larger or smaller and why?

Answer 2

Each pass is smaller than the one before it, as the gasses cool by contact and have less volume

Question 3

If you used 3 ton of coal in an 8 hour shift and averaged 150 Boiler HP what was the rate of evaporation?

Answer 3

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.

Question 4

How do you start a boiler with a copes feed water regulator on it, and explain?

Answer 4

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.

Question 5

Describe the operation of the centrifugal pump.

Answer 5

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.

Question 6

How is the discharge pressure of a stage of a centrifugal pump determined?

Answer 6

It is the calculation of impeller size. Impeller speed, friction losses and the size of the suction and discharge.

Question 7

Describe a motor driven rotary pump.

Answer 7

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.

Question 8

Give seven advantages of a rotary pump

Answer 8

a. Self priming
b. Low NPSH requirements
c. Can handle high viscosity liquids at a high efficiency
d. Wide speed range
e. Are available for low capacity, high head or high capacity applications.
f. Capable of high suction lifts
g. Slip is low

Question 9

How high will a rotary pump lift water?

Question 10

What is a Vent condenser.

Answer 10

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.

Question 11

What do you check on a turbine hourly, monthly, yearly?

Answer 11

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.

Question 12

What is the difference between an open feed water heater and a D.A. tank?

Answer 12

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.

Question 13

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?

Answer 13

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
ACTUAL QUESTION IS 200FT, 150LBS, 90 DEGREES

Question 14

List six qualities of lubrication oil.

Answer 14

Filterability, Low viscosity, hold up under heat, good cooling properties, low acid, acts as a good moisture barrier.

Question 15

On a enclosed compressor how is ammonia removed from the crank case?

Answer 15

A bye-pass line is installed from the crank case to the suction line.

Question 16

Describe an evaporative condenser.

Answer 16

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.

Question 17

How often are M.S.D.S. sheets inventoried?

Answer 17

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.

Question 18

E.P.A. requires what records to be kept regarding under ground fuel tanks?

Answer 18

Upon request you must provide to EPA records on installation, monitoring, cathodic
protection, release detection equipment calibration, maintenance repairs and closures.

Question 19

Name the components of the magnetic circuit of the dynamo.

Answer 19

Field coils, air space, poles and rotors.

Question 20

Define cycle.

Answer 20

One complete positive and negative alternation of a wave form in a AC circuit.

Question 21

Define frequency.

Answer 21

The number of occurrences in a unit of time, such as the voltage in an A.C. circuit.

Question 22

How is frequency controlled in an alternator?

Answer 22

ALTERNATOR FREQUENCY depends upon the speed of rotation and the number of pairs of rotor poles

Question 23

How is voltage controlled in an alternator?

Answer 23

By changing the rotating speed of the D.C. exciter generator.

Question 24

Alloy, what is it?

Answer 24

A mixture of two or more metals blended together. Steel and brass are two types.

Question 25

What is a push nipple?

Answer 25

Holds a sectional boiler together.

Question 26

Water column piping, maximum and minimum Dia?

Answer 26

Minimum 1”, Maximum 2 ½”, blow off line ¾”

Question 27

Flexible coupling?

Answer 27

Quiet, less wear, easily aligned.

Question 28

Combustion?

Answer 28

A chemical reaction between oxygen and combustibles, a process of rapid oxidation by which heat energy stored in fuel is liberated.

Question 29

Tube ligaments?

Answer 29

It is the area of metal in the tube sheet between the tubes.

Question 30

HRT how is it supported? Why?

Answer 30

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.

Question 31

HRT slope?

Answer 31

1” to 3” from front to rear for drainage and circulation.

Question 32

Power pump?

Answer 32

A pump with a adjustable variable stroke and can be used in chemical feeding with a precise volume control.

Question 33

Two types of evaporators

Answer 33

In refrigeration you have Dry (droplet) type and the Flooded type.

Question 34

Your CO2 is at 22%, what are you doing wrong or right?

Answer 34

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.

Question 35

What percent of air is oxygen by volume, by weight?

Answer 35

Air is 21% oxygen by volume and 23% oxygen by weight.

Question 36

Why is HRT boiler dangerous?

Answer 36

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.

Question 37

Name 5 controls on a fuel train.

Answer 37

Soleniod valve, pressure regulating valve, temperature regulating valve, temperature cut-outs and pressure cut-outs, gauges, pumps, heaters.

Question 38

What provisions are made on a watertube boiler with curved tubes for tube removal?

Answer 38

Some of the tubes are left out, tubes are staggered, and every other row is omitted.

Question 39

What is a badge plate? Where is it located?

Answer 39

Locomotive steam boilers have a badge plate attached to the boiler backhead located in the cab, it displays allowed steam pressure.

Question 40

NFPA diamond, what does Blue 1, Red 3 indicate?

Answer 40

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.

Question 41

Chief difference in design between a condensing and non-condensing high pressure turbine?

Answer 41

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.

Question 42

3. What is meant by flash point, ignition (fire) point, and pour point?

Answer 42

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.

Question 43

31. What is an orsat apparatus? Where is it used? Why is it used?

Answer 43

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.

Question 44

37. How do you regulate the blow-down of a safety valve?

Answer 44

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.

Question 45

38. What effect does soot have on the heating surfaces?

Answer 45

Soot acts like an insulator reducing the heat transfer and interfering with the draft, lowering efficiency.

Question 46

40. Give three reasons to treat boiler water.

Answer 46

Reduces scale, prevents foaming and priming, and reduces corrosion and improves efficiency.

Question 47

When do you blow down the gauge glass?

Answer 47

Cold boiler start-up. 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.

Question 48

111. Draw a one pump, and a two pump feed water system.

Question 49

129. How would you change the discharge pressure of a single stage centrifugal pump?

Answer 49

Install a PRV, change the speed, throttle the discharge, trim the impeller.

Question 50

134. What conditions are reaction turbines best suited?

Answer 50

They are made for all steam conditions, but generally designed to operate on low pressure exhausting into a condenser.

Question 51

135. What forms of energy losses are in a turbine?

Answer 51

Steam leakage friction between stages, Eddy friction losses, Windage friction, Radiation, Mechanical friction, Steam velocity losses from last stages to condenser.

Question 52

138. Define over speed?

Answer 52

It could be a safety trip device, or a speed in excess of its design, such as, a turbine is 10%

Question 53

141. What is seal stripping?

Answer 53

These are sealing strips between turbines stages to reduce leakage between stages.

Question 54

142. What is a dummy packing, dummy piston and where are they located?

Answer 54

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.

Question 55

146. What is a Jet condenser? A barometric condenser? A water-leg condenser?

Answer 55

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.

Question 56

148. Explain how a disk flow condenser works.

Answer 56

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.

Question 57

149. What is a Vent condenser.

Answer 57

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.

Question 58

152. When installing a steam header what factors must be taken into consideration?

Answer 58

You must consider adequate support for expansion and contraction, operating pressure, velocity and pressure drop, insulation, valve location, trap location, flow of condensate.

Question 59

54. What are two types of welds on boiler construction and repair?

Answer 59

(SAW) Submerged Arc Welding; (OAW) Oxyacetylene Welding; (SMAW) Shielded Metal Arc Welding flux cored arc welding (FCAW)

Question 60

155. 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?

Answer 60

34.5 X 970.3 BTU’s = 33,475.35 BTU’s/hp

Question 61

157. 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?

Answer 61

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

Question 62

159. What is a congealing tank?

Answer 62

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.

Question 63

161. Explain the purpose of the accumulator and how it works.

Answer 63

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.

Question 64

165. What is the main difference between an A.C. generator and a D.C. generator?

Answer 64

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.

Question 65

168. What is excess air?

Answer 65

Amount of air in excess of the theoretical amount needed for complete combustion.

Question 66

170. Define factor of safety?

Answer 66

A comparison of tensile strength to actual working stress – bursting pressure / working pressure.

Question 67

171. What is a permit space, how does an operator know when one is needed?

Answer 67

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.

Question 68

17. How do you determine the size of a receiver on an ammonia cooling unit for a large company?

Answer 68

The unit must be large enough to contain everything in the system, including the piping, and allow for 20% expansion.

Question 69

55. Sketch a steam header valve arrangement.

Answer 69

Draw boiler, non return valves with drains, then header

Question 70

21. How are gasses formed in an ammonia system?

Answer 70

Heat is absorbed in the evaporating coil which causes the liquid to boil until vaporization is complete.

Question 71

79. What valves are on the feed line to the boiler?

Answer 71

One feedwater regulator with 2 gate valves and a bypass globe valve, also a check valve.

Question 72

In the boiler tubes section, one question asked “Where do corrosion happen?”

Answer 72

* 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

Question 73

Question about holdover in refrigeration.

Answer 73

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.

Question 74

173. What is a congealing tank?

Answer 74

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.

Question 75

Five advantages of fire tube boilers

Answer 75

* 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 easy to transport and install * fuel efficient, easy to operate * low first cost, reliability in operation, less draught required, quick response to load changes

Question 76

362. Blowdown tank?

Answer 76

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.

Question 77

How Kingsbury's Thrust Bearing Works

Answer 77

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

Question 78

How often are M.S.D.S. sheets inventoried?

Answer 78

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.

Question 79

382. Name two types of evaporators?

Answer 79

In refrigeration you have Dry (droplet) type and the Flooded type.

Question 80

Why is hollow tubes stronger than solid tubes?

Answer 80

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