MN Boiler Exam Questions with 100% Correct Answers | Verified | Updated 2024, Exams of Advanced Education

Download MN Boiler Exam Questions with 100% Correct Answers | Verified | Updated 2024 and more Exams Advanced Education in PDF only on Docsity! MN Boiler Exam Questions with 100% Correct Answers | Verified | Updated 2024 Cast Iron Sectional Boiler - Correct Answer-Like Bread, sections in between are intermediate. Held together with push nipples and stay bolts. No special foundation required Expandable (can add more centers to increase heating capacity) Boiler trim mounted on end sections Disadvantage: Always low pressure Advantage: corrosion resistant Firetube boiler - Correct Answer-used for heating and process Gas/heat of combustion on one side and water on outside. Horizontal Return Tubular - Correct Answer-Type of firetube Drum supported by Lugs and Slings Old construction, not efficient because of *External furnace* 2 pass construction pg. 1 professoraxe l Bridgewall - Correct Answer-Baffle inside HRT boiler furnace to direct flow of combusting gases for greatest efficiency Scotch Marine - Correct Answer-Most common, most efficient Firetube boiler. Comes in 2, 3, or 4 pass construction Round tube furnace usually corrugated like culvert under road. *Completely internal furnace* Dry Back Scotch Marine - Correct Answer-easy to clean and maintain, less costly, less efficient Wet Back Scotch Marine - Correct Answer-hard to clean and service due to limited access, more efficient, more costly Fire Box - Correct Answer-almost like Scotch Marine but fire box instead of corrugated. Can burn oil, gas, or solid materials Locomotive - Correct Answer-Type of firetube used in trains. Variation of HRT, partially enclosed furnace pg. 2 professoraxe l Baffle - Correct Answer-used in all boilers (fireside and waterside) to direct flow for greatest efficiency How is piping measured vs. boiler tubes - Correct Answer- piping is measured based on inside diameter, while boiler tubes are measured by outside diameter Dry Pipe - Correct Answer-Pipe running along the top of steam space in which slots are cut in top or side for purpose of admitting only dry steam to line. One has blank ending, other is connected to steam outlet. Drain holes drilled on bottom. What is the point of a dry pipe - Correct Answer-to aid in removal of moisture from steam as it leaves the steam drum what kind of stamp must a company posses to to weld on boilers - Correct Answer-R stamp ASME - Correct Answer-American Society of Mechanical Engineers pg. 5 professoraxe l According to ASME, how many valves must be on the main steam line of a high pressure steam boiler? - Correct Answer- 2. Jurisdiction ends after second. Longitudinal joint - Correct Answer-Joint subject to greatest stress Bottom Blowdown Valve - Correct Answer-removes sludge and sediment, drains boiler for maintenance, located on bottom of mud drum in WTB or bottom of boiler on Firetube Breeching - Correct Answer-exhaust pipe between boiler and chimney Hot Water SUPPLY Boiler - Correct Answer-water heater for domestic use Safety *Relief* Valve - Correct Answer-Prevents overpressure of water boiler. Spring loaded pop type, discharge capacity rated in Btu/hr. Must be hand tested quarterly in all boilers. Minimum size 3/4. Can be T&P or Pressure only pg. 6 professoraxe l How often does a Safety Relief Valve need to be tested - Correct Answer-Quarterly Minimum size for safety relief valve - Correct Answer-3/4 Superheater - Correct Answer-increases steam temp but not pressure. allows for use of steam longer. Increases efficiency. exposes steam to combustion gases so it won't condense after first stage of steam turbine. Located in radiant outlet area of boiler Dry firing - Correct Answer-flow of steam is necessary to keep superheater from overheating and getting damaged Reheater - Correct Answer-increases steam temp for latter sections of steam turbine Economizer - Correct Answer-preheats feed water pre heater - Correct Answer-pre heats combustion air. Important in solid fuel burners. pg. 7 professoraxe l radiation - Correct Answer-electrical energy waves. Heats objects not air What must a heat transfer surface have? - Correct Answer- must have heat of combustion on one side and water or steam on the other 1 Horsepower as related to evaporation - Correct Answer- evaporation of 34.5 lbs of water per hour Why would superheated steam be preferred to wet steam? - Correct Answer-used to provide dry steam to turbines sensitive to wet steam. Can be used when high temperatures are needed. Allows more work to be done. Desuperheating - Correct Answer-brings down to lower temp. Atomization - Correct Answer-Air, steam, mechanical/pressure, rotary cup (constant capacity used in heavy oil burners) Draft - Correct Answer-Difference between inside furnace and outside air. Causes air to move. measured in inWater. pg. 10 professoraxe l 4 Types of draft - Correct Answer-Forced, Induced, Balanced, Natural Forced Draft - Correct Answer-pushes air into combustion chamber. Located at inlet side of burner Induced draft - Correct Answer-pulls or sucks air through furnace. Located in breeching Balanced Draft - Correct Answer-combination of forced and induced Natural draft - Correct Answer-always present. Controlled by height of chimney and temp. differential #2 oil - Correct Answer-Most common heating fuel, does not require pre heating for pumping or burning How many Btu/G does #2 oil have - Correct Answer-141,000 Btu/G pg. 11 professoraxe l Gas - Correct Answer-Propane, butane, natural Natural Gas (NAG) - Correct Answer-no ash, already aerosol, easy mix with air, cleanest burning 1 therm - Correct Answer-100,000 Btu 1 cubic foot - Correct Answer-1000 Btu Perfect combustion - Correct Answer-exact amt. of air is used to burn all the available air to CO2 and water Ratio of fuel to air - Correct Answer-15 lbs fuel to 1 lb air complete combustion - Correct Answer-burning of all available fuel with minimum excess air incomplete combustion - Correct Answer-caused by insufficient combustion air which causes formation of smoke/soot/CO pg. 12 professoraxe l When is the explosion hazard greatest? - Correct Answer- when operating at low load and start up What is the best indication of efficiency? - Correct Answer- Temp of exhaust gases Electrostatic Precipitators (ESP) - Correct Answer-remove dust particles in exhause Globe valve - Correct Answer-Fluid flows through globe valve changes direction several times causing resistance to fluid flow and pressure drop Pressure Reducing Valve (PRV) - Correct Answer-converts high or fluctuating inlet pressure to a lower and constant outlet pressure Relief Valves - Correct Answer-Relieve T and P or P only. T and P on water heaters, P relief on hot water boilers. 4 subsystems necessary for plant to run - Correct Answer- steam, feed, fuel, and draft pg. 15 professoraxe l Open Feed water heater - Correct Answer-vented to atmospher. STeam and condensate in direct contact, located on suction side of feed pump. Provides positive suction head for feed pump. Air and non condensable gases leave through atm. vent. Deaerator is an open feed water heater Closed feed water heater - Correct Answer-usually a shell and tube heat exchanger operates at feed line pressure. located on discharge side of feed pump Centrifugal - Correct Answer-Most common type of pump in plant What is the most common cause of boiler failure - Correct Answer-low water MAWP - Correct Answer-Max Allowable Working Pressure Compound gauge - Correct Answer-measures vacuum and P pg. 16 professoraxe l syphon/pigtail - Correct Answer-protects gauges and instruments from steam Cross Tee - Correct Answer-allows for inspection and check for obstruction automatic non return valve - Correct Answer-mounted on main steam return valve. In plants with more than one boiler. can be used for isolation on lock out tag out 3 types of steam traps - Correct Answer-Thermostatic, float thermostatic, inverted bucket (longest life cycle) Line steam separator - Correct Answer-excessive moisture is prevented from entering steam turbine steam trap - Correct Answer-removes air and condensate, separates condensate from heating equipment. How does condensate return to the boiler in a one pipe steam heating boiler system - Correct Answer-through main steam line pg. 17 professoraxe l minimum/maximum size steam safety valve - Correct Answer- 3/4" on conventional boiler, 1/2" on miniature boiler, max size 4 1/2" boilers > 500 sq. ft. must have how many safety valves - Correct Answer-2 how far from a walkway and floor must discharge be? - Correct Answer-with in 18" of floor or through wall/roof but not with in 7 ft. of walkway what must be done with a steam safety valve during a hydrostatic test if left attached? - Correct Answer-must be gagged or test clamped Blowdown/Blowback minimum - Correct Answer-2 psi, max is 6% MAWP Accumulation test - Correct Answer-must relieve all pressure on boiler at 100% firing rate and not exceed 6% MAWP discharge capacity - Correct Answer-rated in lbs. steam / hr pg. 20 professoraxe l Pressure reducing valve (PRV) - Correct Answer-must have steam safety valve on low pressure side Huddling chamber - Correct Answer-formed by blowdown ring and simmering ring. adjusts amount of blowdown Water column - Correct Answer-reduces turbulence for more accurate water level reading what is the minimum pipe size for a water column. - Correct Answer-1" If an isolation valve is present between water column and boiler, what type of valve must it be? - Correct Answer-O, S &Y gate valve How often must a water column be blown down - Correct Answer-High Pressure steam once a shift, Low pressure steam daily, none on water boiler pg. 21 professoraxe l If the primary method of checking the water level is unusable what can you do - Correct Answer-use secondary method (tri cocks) until repair is made Low Water Cut Off - Correct Answer-must be installed on all boilers. can be float or probe type. Primary is usually auto reset but secondary must be manual reset. Purpose is to secure fuel to burner in event of low water condition Low water condition - Correct Answer-water still visible in gauge glass. water can safely be added low water casualty - Correct Answer-non recoverable event Water not visible in gauge glass or unknown. Immediately secure fuel to burner. DO NOT ADD WATER. boiler must be secured, cooled and inspected by chief of plant for signs of overheating electrical/mechanical safety device - Correct Answer-second most important safety feature Feedwater regulator - Correct Answer-controls water level in boiler pg. 22 professoraxe l Thermal shock protection - Correct Answer-low limit control used to prevent thermal shock steam flow meter - Correct Answer-measures qty. of steam in lbs steam / hr. Bottom Blowdown valves ( <100 Psi vs >100 PSI) - Correct Answer-one valve if less than 100 psi, 2 valves if greater than 100 psi where should the quick acting valve be if the boiler is equipped with 2 valves for the bottom blowdown? - Correct Answer-It must be positioned closest to boiler, opened first, and closed last. Slow opening (screw valve) - Correct Answer-must turn a minimum of 5 complete turns between shutting and opening What is the first thing to do when entering room - Correct Answer-blowdown sight glass to check water level how can you tell your sight glass is not working properly - Correct Answer-water has no movement pg. 25 professoraxe l What should you do with a boiler during a bottom blowdown - Correct Answer-boiler should be on light load and water level at NOWL What is the purpose of flooding superheater on start up - Correct Answer-to prevent dry firing foaming - Correct Answer-occurs when fuel oil or other contaminants introduced to boiler water Carry over - Correct Answer-anything that leaves boiler with steam Priming - Correct Answer-small particles of water carried over into steam line water logged - Correct Answer-when water is added to a new hot water system there is a rapid increase in pressure what does it mean when the relief valve pops when burner starts firing - Correct Answer-water logged pg. 26 professoraxe l What is the best measure of boiler efficiency - Correct Answer- exhaust gas temperature 3 types of blowdown - Correct Answer-surface blow, continuous blow, bottom blow Wet layup - Correct Answer-used for short interval when boiler may be needed on short notice, fill completely with feedwater and additional O2 scavenger Dry layup - Correct Answer-Most preferred, economical method, extended time frame/period or if boiler may freeze External water treatments (4 types) - Correct Answer-softener (best), demineralizer, R. O. and clarifier Internal water treatment - Correct Answer-Treats boiler using chemicals after water enters boiler external water treatment - Correct Answer-treats water by mechanical or other means prior to entering boiler pg. 27 professoraxe l Hot water Monthly After installing new gauge glass, what should you do - Correct Answer-open steam then water to allow it to warm up Hydrostatic test - Correct Answer-checks for leaks in boiler. Temp should be 70F Before entering boiler for cleaning - Correct Answer-check for hazardous atm., purge vent furnace and or drum, tag and lock out all power sources after boiler off line, drained, and cooled How can you detect a leak around steam condenser - Correct Answer-shaving cream or a flame Best way to check steam trap for proper operation - Correct Answer-stethoscope Internal inspection - Correct Answer-Structural integrity, fireside and waterside, check for soot scale and overheating, check for conformance to boiler code pg. 30 professoraxe l Attendance for 0-30 Hp, 31-200 Hp, +200 Hp, 300+ Hp - Correct Answer-0-30 in Hp boiler plant must be checked daily, 31-200 may be left unattended for no more than 2 consecutive hours when occupied by the public but not approaching continual absence. 200+ when in operation requires constant attendance. May leave for up to 30 min but must be within 500 ft at all times 300+ must have chief engineer who ensures safe operation and maintenance of boiler plant Classifications of A, B, C - Correct Answer-A- High Pressure steam with turbine or engine B- High pressure steam/ Hot water C- Low Pressure steam /hot water Special class license - Correct Answer-Experience required- 0 years Take Charge 50 Hp Shift engineer 100 Hp (can operate any HP/ Low P under direct supervision of proper licensed engineer) A - NA pg. 31 professoraxe l 2nd Class license - Correct Answer-Experience required- 1 year Take Charge 100 Hp Shift engineer 500 Hp A - 1 year 1st Class License - Correct Answer-Experience required- 3 years Take Charge 500 Hp Shift engineer Unlimited Hp A - 2 years Chief Class License - Correct Answer-Experience required- 5 years (Must hold first license for 1 year) Take Charge Unlimited Hp Shift engineer Unlimited Hp A - 2 years Low Pressure Steam and Low Pressure Hot Water MAWP - Correct Answer-LP steam 15 psi and LP Hot water 160 psi and 250F pg. 32 professoraxe l Water columns of steel must be used.... - Correct Answer-if pressure is over 350 psi If a steam gauge has a stop cock what kind must it be - Correct Answer-T or lever valve How far do the graduations on a steam gauge on a low pressure boiler go? - Correct Answer-1 1/2 to 2 times the MAWP What is the minimum size op pipe diameter that may be used to attach a steam gauge to a steam boiler - Correct Answer- 1/4 inch What should you do if the safety valve will not close? - Correct Answer-Lift lever to clear debris According to MN code, what kind of valve must be used if they are over 2 inches in diameter - Correct Answer-rising stem valve What must be between 2 steam stop valves on a steam header line? - Correct Answer-drain valve pg. 35 professoraxe l Water leaving the blowdown tank and entering a sanitarty sewer system must not exceed what temperature - Correct Answer-150F When must you use a blow off valve of steel - Correct Answer- when the psi is over 200 When can stop valves be eliminated for a single hot water heating boiler - Correct Answer-when the boiler is located at the top or above the system. pg. 36 professoraxe l