City of O City of Omaha 3rd Grade N.A.P.E. Stationary Engineers Test WITH CORRECT ANSWERS, Exams of Nursing

Download City of O City of Omaha 3rd Grade N.A.P.E. Stationary Engineers Test WITH CORRECT ANSWERS and more Exams Nursing in PDF only on Docsity!

City of Omaha 3rd Grade N.A.P.E.

Stationary Engineers Test WITH

CORRECT ANSWERS

How can you lose your license? - CORRECT ANSWER Drinking on the job / sleeping on the job /

negligence / unsafe work / failing to renew your license annually / signing a falsified licensing application for someone

What must you do if you change jobs? - CORRECT ANSWER You must notify city hall if you change

jobs, change your address or if you retire

Why should you do rounds? - CORRECT ANSWER You do rounds so that you can find and correct

problems to prevent break downs. Keeping permanent records will make it easier to forecast most breakdowns because you will get to know your equipment.

What is a steam Boiler? - CORRECT ANSWER A steam boiler is a closed vessel PARTIALLY FILLED

with water, under pressure, that transforms water into steam with the application of heat.

What are requirements of a good boiler? - CORRECT ANSWER 1. simple

2. designed to accommodate expansion and contraction
3. adequate steam and water space
4. efficient
5. responsive to demands
6. accessible for cleaning and repair
7. safe

Name and describe three types of heat transfer used in boiler operation. - CORRECT

ANSWER RADIANT HEAT-is heat radiated from a hot to cold body and depends on the temperature

difference and the color of the body that receives the heat. The heat from the sun reaches us by means of radiation. CONDUCTION HEAT-is heat that passes from the gas to the tube by physical contact. The heat passes from molecule of metal to molecule of metal with no displacement of the molecules. CONVECTION HEAT-is heat transmitted from a hot to cold body by movement of the conveying substance.

What is a combustion chamber? - CORRECT ANSWER The area of a boiler where the burning of fuel

occurs

What is an internally fired boiler and name 4 types. - CORRECT ANSWER Internally fired boilers are

those in which the grate and combustion chamber are enclosed within the boiler shell. Scotch Marine Cast iron package Steam locomotive Vertical fire tube

What is an externally fired boiler and name 4 types. - CORRECT ANSWER Externally fired boiler is a

boiler in which the setting, including furnace and grates are separate and distinct from the boiler shell. Horizontal return tube set on brick Heine Cast iron set on brick

What is the difference between a flue and a tube? - CORRECT ANSWER A tube is 4 inches or less in

diameter measured externally. A flue is 4 inches or more in diameter measured internally.

What is a dry pipe and where is it located? - CORRECT ANSWER The dry pipe is a steam separator

located within the boiler shell and connected to the steam outlet. Its upper surface is perforated. Steam enters the perforations rapidly changing its direction of flow before entering the steam outlet. This causes droplets and impurities to separate the steam.

Describe a scotch marine boiler and how it is fired? - CORRECT ANSWER A scotch marine boiler is

an internally fired self contained horizontal return fire tube boiler. It is a cylindrical shell containing the combustion chamber and tubes that are surrounded by water.

How is a sterling boiler suspended? - CORRECT ANSWER Lugs on the ends of the upper drums rest

on the beams of its structure. The lower (mud) drum is suspended from the tubes and is free to move by expansion.

Describe the circulation of water within the sterling boiler. - CORRECT ANSWER Feedwater enters

the top rear drum, passes down the rear tubes to the mud drum. Steam and boiler water go up the front banks of tubes to the front and center drums. Circulator tubes allow the boiler water to pass between drums. What does not go out as steam goes back down the rear tubes.

What provisions are made for tube removal on water tube boiler? - CORRECT ANSWER Some tubes

are left out. The tubes are staggered. Sometimes every other row is omitted. What is a water tube boiler? What are five advantages and five disadvantages of a water tube boiler?

What are five types of water tube boilers? - CORRECT ANSWER A water tube boiler is a boiler in

which the products of combustion pass around the tubes containing boiler water.

Advantages - they are rapid steamers - they use less water - they have less of a chance of exploding - they have no flat surfaces - they have smaller tube sizes Disadvantages - they have elaborate settings - they are field assembled - initial cost per lb. of steam is higher - greater number of openings thus more air filtration needed - need large floor space Four types - B&W - Sterling - Hiene - Riley - Consolidated - F.M. Package - M&H - Cross Drum Straight Tube - DAO Type What is a fire tube boiler? What are five advantages of a fire tube boiler and five disadvantages of a fire

tube boiler? Name four types of fire tube boilers. - CORRECT ANSWER A fire tube boiler is a boiler

in which the products of combustion pass through the tubes or flues that are surrounded by water. Advantages - Low cost - small floor space - factory assembled - fast installation Disadvantages - liable to explosions - drums and joint set over the fire - inaccessible for inspection - poor circulation - slow steamer - inefficient Four types - HRT - Vertical - Scotch Marine - Locomotive

What types of stays are used in wet back (Scotch Marine) type boilers? - CORRECT ANSWER Stay

bolts through stays These will sometime have a telltale hole drilled into them so if they leak it will whistle.

Describe a sectional Boiler. - CORRECT ANSWER The sectional headers are built up of vertical

sections or units. A sufficient number of sections are clamped together to form the desired size of a

What is A.S.M.E. and its purpose? What code information is stamped on the boiler? What is an A.S.M.E.

stamp? Where are the code markings found on a boiler? - CORRECT ANSWER A.S.M.E - American

society of mechanical engineers It is a code of minimum standards for the safe construction of pressure vessels. Stamped on the boiler shell or plate attached to the shell there will be - the safe working pressure - date of manufacture - name of manufacture - type of material used - hp rating - square feet of heating surface - steam generation in lbs. per hour - fuel designed for The A.S.M.E. stamp will identify the boiler or accessory type. On a fire tube boiler, it will be located on the right side near the front of the boiler, near the water column. On a water tube boiler, it will be located next to the manhole on the steam drum.

What is the cross section of a 1 inch bolt? - CORRECT ANSWER Diameter x Diameter x .7854 =.

What is an alloy? Name five. - CORRECT ANSWER An alloy is a mixture of two or more metals.

Types - brass, stainless steel, cast iron, steel, pewter, Babbitt

At what pressure is the use of cast iron fittings permitted? - CORRECT ANSWER 15 psi or 250

degrees F not to exceed either one

What is meant by factor of safety? - CORRECT ANSWER Factor of safety is the comparison of the

tensile strength to the actual working stress. The bursting pressure divided by the working pressure.

What is the factor of safety for boilers, flywheels and pipe? - CORRECT ANSWER New boilers - 4

Pre-owned boilers constructed to A.S.M.E. code is - 5 Flywheels - 3 Pipe - 8

What is a lap joint? What is a butt joint? What is a butt strap joint? - CORRECT ANSWER A lap joint

is when one plate overlaps the other and is jointed. A butt joint is when two ends of the plate meet end to end and are jointed. A butt strap joint is two joints, one plate is butted and joined and the other two plates are overlapped over the butt joint and joined.

Is the longitudinal joint the strongest part of the boiler? - CORRECT ANSWER NO

The longitudinal joint is the strongest joint, but any joint is the weakest part of the boiler. Two boilers are made of the same grade of steel, same thickness of plate and same type of joints. One is 30 inches in diameter and the other is 60 inches in diameter. Which will withstand the greatest working

pressure? - CORRECT ANSWER The 30 inch boiler will because it has less total pressure on the shell.

What are tube ligaments? - CORRECT ANSWER A tube ligament is the area between the tube holes

on the tube sheet.

A gusset stay consists of boiler plate riveted to the shell and head or tube sheet by means of angle iron. They are more rigid. Both are used to brace right angle surfaces. Why are handholes and manholes made oval instead of round? What are minimum sizes for manhole

and handhole openings? - CORRECT ANSWER So they can be inserted into and removed from their

respective openings in the boiler. Manhole 11 x 15 or 10 x 16 Handhole 2.75 x 3.

What is thermal efficiency and what is a good percentage? - CORRECT ANSWER It is the ratio of

heat supplied by fuel to heat absorbed by the boiler. A good percentage is 85%

How do you determine boiler capacity and what is boiler heating surface? - CORRECT

ANSWER Total heating surface determines the capacity of the boiler.

Heating surface is any area that has hot gases on one side and boiler water on the other. It is measured from the fire side.

What is furnace volume? Is furnace volume measured in square feet or cubic feet? - CORRECT

ANSWER Furnace volume is the space available for complete combustion of the fuel before the

products of combustion enter the heat absorbing section of the boiler.

This varies with the type of fuel used. Furnace volume is measured in cubic feet.

What is superheated steam? Does its temperature rise? - CORRECT ANSWER Superheated steam is

steam that has been heated to a high temperature, but its pressure remains the same. Yes superheated steams temperature does rise.

Define flash point, ignition point, and pour point. - CORRECT ANSWER Flash point - the lowest

temperature at which vapors of a substance will make a flash of flame but not continue to burn when exposed to open flame. Ignition point - the lowest temperature at which vapors of a substance will ignite and burn continuously when exposed to an open flame. Pour point - the lowest temperature at which liquid will flow.

Define combustion - CORRECT ANSWER Combustion is a chemical combination of oxygen with the

combustible elements of fuel, such as carbon and hydrogen, and this results in the production of heat. What is rate of combustion? Does air and fuel have any relationship in figuring the rate of combustion? -

CORRECT ANSWER Rate of combustion is the rate at which heat is released from a fuel.

Yes - When oxygen and combustible are mixed in definite proportion at an elevated temperature and given proper time, they will combine completely.

Define Perfect, Complete and Incomplete combustion. - CORRECT ANSWER Perfect - burning all the

fuel using only the theoretical amount of air Complete - Burning all the fuel using more than the theoretical amount of air Incomplete - when a portion of the fuel remains unburned because of insufficient amounts of air

What is excess air? - CORRECT ANSWER The amount of air in excess of what is theoretically needed

for complete combustion.

In a flue gas analysis, what do you consider a good percent of CO2? - CORRECT ANSWER 12% - 15%

With 20% ideal, but mostly unattainable

How is the density of smoke measured? - CORRECT ANSWER With an opacimeter or a ringleman

chart

What grades of smoke are allowed in boiler operation? - CORRECT ANSWER No darker than grade 1

for more than 5 minutes per hour and no more than 3 times in a 24 hour period

What are 7 heat losses in a boiler? - CORRECT ANSWER Moisture in the air

Moisture in the fuel Moisture formed in the burning of hydrogen Incomplete combustion Unburned carbon in the ash Heat carried away in dry flue gases Radiation and other losses

What is the heat content of one pound of good coal and one pound of carbon? - CORRECT

ANSWER Coal - 13,000 - 14,000 BTU's

Carbon - 14,540 BTU's

What is an Orsat Apparatus? Where is it used? Why is it used? - CORRECT ANSWER A flue gas

analyzer to determine the amounts of CO, CO2, and O2 in flue gasses. Combustion gasses are sampled from the last pass or the breeching.

What is a Fyrite analyzer? Where is it used? Why is it used? - CORRECT ANSWER It is a flue gas

analyzer to determine the amounts of O2 and CO2 in flue gasses. Combustion gasses are sampled from the last pass or the breeching. It helps determine combustion efficiency.

What is a pyrometer? - CORRECT ANSWER A pyrometer is a thermometer for measuring

temperatures above the range of mercury. It would be located in the hot gas passages and are in the refractory.

What are tuyeres? - CORRECT ANSWER Tuyeres are air admitting grates on a stoker.

What is a water back? - CORRECT ANSWER The water back is a water wall that is behind the grate

on a stoker and its purpose is to cool the wall to prevent clinkers from sticking to the back wall.

Define purging and name two types. - CORRECT ANSWER Purging is the forced removal of

combustibles from the firebox. Pre-purge is purging the firebox before the pilot is lit. Post-purge is purging the firebox after the combustion cycle.