STEAM BOILERS, ENGINES, NOZZLES AND TURBINES

Vinay V. Ankolekarvinay.ankolekar@gmail.com 9762310273Department of Mechanical Engineering Sinhgad Academy of Engineering, Kondhwa, Pune, Maharastra

3.1 Cochran boiler is a _____boiler.(a) Vertical Fire Tube (b) Horizontal Fire Tube (c) Horizontal Water Tube (d) Vertical Water Tube

(a) Vertical Fire Tubea

3.2 Lancashire boiler is a ______. (a)

Mobile Fire Tube (b) Stationary Fire Tube (c) Stationary Water Tube (d) None of the above

(b) Stationary Fire Tubeb

3.3 Fire tube boilers are those in whichd

(a) Forced circulation takes place (b) Tubes are laid vertically (c) Water passes through the tubes & flue gases surround them (d) Flue gases pass through tubes & water surrounds them(d) Flue gases pass through tubes & water surrounds them

3.4 .is a fire tube boiler. (a)

Stirling boiler (b) Locomotive (c) Bacbcock & wilcox boiler (d) None of the above

(b) Locomotiveb

3.5 .is a water tube boiler. (a)

Cornish boiler (b) Lancashire boiler (c) Locomotive boiler (d) Babcock & Wilcox boiler

d

(d) Babcock & Wilcox boiler

3.6 A high pressure boiler is one which produces steam at a pressure of (a)

more than 10 bar (b) more than 30 bar (c) more than 50 bar (d) 75-80 bar

(d) 75-80 bard

3.7 Why is the crown of the fire box made hemispherical ? (a)

To withstand pressure in boiler (b) To give maximum space (c) To resist intense heat in fire box (d) To give max. strength(c) To resist intense heat in fire boxc

3.8 In a boiler the basic purpose of a drum isa

(a)

To separate steam from water (b) To remove salts from water (c) To serve as storage of steam (d) All of the above (a) To separate steam from water

3.9 Compared to controlled circulation boilers the dia. of tubes for natural circulation boiler is (a)

less (b) more (c) same (d) none of the above

(b) moreb

3.10 ---------- is best suited to meet fluctuating demands. (a)

Cornish boiler (b) Locomotive boiler (c) Cochran boiler (d) Lancashire boiler

(b) Locomotive boilerb

3.11 What is the no. of drums in Benson steam generators ? (a)

One (b) Two (c) either (a) or (b) (d) No drum

(d) No drumd

3.12 Why is fusible plug fitted in small boilers?(a) To control steam temp. (b) To remove molten ash (c) To avoid explosion (d) To extinguish fire if water levelin the boiler falls below alarming limit(d)d

To extinguish fire if water level in the boiler falls below alarming limit

3.13 Where is the fusible plug in small boilers located? (a) Above

the steam dome (b) At the inlet chimney (c) Over the combustion chamber (d) In the drum(c) Over the combustion chamberc

3.14 The fusible plug is made of fusible metal containing? (a)

tin, lead and iron (b) tin, lead and bismuth (c) tin, lead and nickel (d) tin, lead and copper

(b) tin, lead and bismuthb

3.15 ------coal has the higher CV. (a)

Bituminous (b) Lignite (c) Peat (d) Authracite

(a) Bituminousa

3.16 In Bituminous coal the percentage of carbon is of the order of (a)

10-20 % (b) 25-40% (c) 40-60% (d) 65-80%

d

(d) 65-80%

3.17 Lanchashire boiler is a -------pass boiler (a)

single (b) two (c) three (d) four

c

(c) Three

3.18 In a locomotive boiler the max. pressure is limited to (a)

4 bar (b) 12 bar (c) 18 bar (d) 30 bar

c

(c) 18 bar

3.19 For a fire tube locomotive boiler which aspect is not valid ? (a)

Multi-tubular (b) Externally fired (c) Mobile unit (d) None of the above

b

(b) Externally fired

3.20 ------- boiler is once through boiler. (a)

Benson boiler (b) Babcock & Wilcox boiler (c) Lancshire boiler (d) Velox boiler

a

(a) Benson boiler

3.21 ------- is fitted on a boiler to improve the boiler efficiency. (a)

Steam trap (b) Blow down cock (c) Safety valve (d) Economiser

d

(d) Economiser

3.22 -------- is a boiler accessory. (a)

Water level indicator (b) Safety valve (c) Superheater (d) Stop valve

c

(c) Superheater

3.23 A supercritical boiler has a pressure range of (a)

30-70 bar (b) 80-120 bar (c) 130-200 bar (d) 225-250 bar

d

(d) 225-250 bar

3.24 In a Babcock & Wilcox boiler baffles are provided in betw. Water tubes to (a)

have better contact of flue gases with water tubes (b) prevent buckling of water tubes (c) regulate steam flow a (d) regulate water flow (a)

have better contact of flue gases with water tubes

3.25 Which of the following boiler can generate superheated steam without additional accessories (a)

Cochran boiler (b) Cornish boiler (c) Lancashire boiler (d) Locomotive boiler (d)

d

Locomotive boiler

3.26 A blow off cock in a boiler is used toa

(a)

remove sludge from boiler (b) drain off water resulting from partial condensation of steam (c) blow air into the furnace (d) allow flue gases to escape to the chimney (a)

remove sludge from boiler

3.27 What is the efficiency of a well maintained boiler ? (a)

30% (b) 50% (c) 70% (d) 90% (d)

d

90%

3.28 What is the efficiency of a thermal power plant ? (a)

10% (b) 18% (c) 30% (d) 50% (c)

c

30%

3.29 --------type of boiler can meet rapid changes of load. (a)

Vertical water tube (b) Horizontal water tube (c) Horizontal fire tube (d) Forced circulation (d)

d

Forced circulation

3.30 Which of the following medium will leak if a safety valve in a locomotive boiler starts leaking? (a)

Wet steam (b) Dry steam (c) Superheated steam (d) Supersaturated steam (c)

c

Superheated steam

3.31 By which of the following is the size of the boiler tube specified ? (a)

OD and ID (b) OD and thickness (c) Mean dia. and thickness (d) ID and thickness (b)

b

OD and thickness

3.32 In locomotives the draught is produced by (a)

Induced draft fan (b) Chimney (c) Steam jet (d) None of the above (c)

c

Steam jet

3.33 Why are boiler stays provided ? (a)

To provide support for boiler (b) To check failure in compression (c) To prevent flat surfaces under pressure from leaning apart (d) All of the abovec

(c)

To prevent flat surfaces under pressure from leaning apart

3.34 Why are gusset stays in a boiler provided ?(a) To check atmospheric air leaking into furnace (b) To check leakage of hot flue gases (c) To prevent the buldging of flat surfaces (d) All of the above c

(c)

To prevent the buldging of flat surfaces

3.35 In a boiler max. energy loss occurs due to (a)

Flue gases (b) Radial losses (c) Incomplete combustion (d) Unburnt carbon in ash

a

(a) Flue gases

3.36 Why is the deaeration of feed water carried out ?c

(a) To reduce weight of water to be handled (b) To reduce cavitations of boiler feed pumps (c) To reduce corrosion caused by oxygen (d) To reduce heat transfer coefficient (c) To reduce corrosion caused by oxygen

3.37 Why is the blow down from the boiler drum carried out ?c

(a) To lower steam pressure (b) To increase steam temperature (c) To control solids concentrations in the boiler water (d) All of the above

(c) To control solids concentrations in the boiler water

3.38 The economizer unit of a boiler is located(a) To lower steam pressure (b) To increase steam temperature (c) To control solids concentrations in the boiler water (d) All of the above (e) None of the abovee

(e) None of the above