Blow off cock is provided in steam boiler to
Guard the boiler in case of abnormal rise in steam pressure
Drain out water and sludge during its repair
Regulate the supply of water in boiler
Put out the fire in the furnace when the water level in the boiler falls to unsafe limit
Correct Answer :
B. Drain out water and sludge during its repair
Related Questions
Hydrogen can be
Used in I.C. engines as fuel
Liquefied & stored under cryogenic conditions
Produced by electrolysis of water
All (A), (B) & (C)
Coating thickness in case of galvanising of steel sheet generally corresponds to the deposition of __________ gms of zinc per 
of steel strip.
5-10
1000-1500
120-500
1500-3000
Inertial forces are obtained, when the elastic forces are multiplied by __________ number.
Mach
Froude
Reynolds
Euler
Which of the following is the most wear resistant grade of carbide used for the cutting tools?
Aluminium carbide
Tungsten carbide
Nickel carbide
Iron carbide
Ammonia gas can be dried by
PCl5
Quick lime
CaCl2
Concentrated H2SO4
Carbon supply in pack carburising process is in the form of
Charcoal
Calcium carbide
Hydrocarbon oil
Graphite
Oxygen cylinders used for autogenous (cutting/welding) purposes are
Seamless & made of steel
Heat treated before use
Made by sand casting
Welded steel cylinders
Case hardening of a material is
Followed by tempering or carburising
Preceded by its tempering
Done to get a soft ductile interior with a very hard surface
Carried out to get extreme hardness in its core
Which of the following approaches the ideal gas behaviour most closely?
Wet steam
Saturated steam
Superheated steam
Saturated water
'GASOHOL' widely used in Brazil as a motor fuel is a mixture of alcohol and
Petrol
LPG
Light hydrocarbon gases (e.g. butane or propane)
None of these
Which of the following does not discharge the dust collected as a dry solid?
Electrostatic precipitator
Wet scrubber
Bag filter
Gravity settling chamber
In inventory control theory, the economic order quantity (EOQ) is the
Lot size corresponding to break even analysis
Average level of inventory
Optimum lot size
None of these
__________ iron is produced by the annealing of white cast iron.
Malleable
Nodular
Ductile
Grey
With increase in annealing temperature, the following defect density decreases.
Vacancy
Dislocation
Grain boundary
All of these
In case of simple harmonic motion, displacement is proportional to the
Velocity
Acceleration
Both (A) & (B)
Neither (A) nor (B)
To counteract the bad effects of strain hardening on a cold formed part, it must be
Tempered
Normalised
Annealed
Hardened
The product out from a cupola is called
Wrought iron
Pig iron
Cast iron
None of these
A particle is settling in a liquid under Stokesian conditions. The free falling velocity of the particle is proportional to
√(Particle diameter)
Particle diameter
(Particle diameter)2
(Particle diameter)3
Electrometallurgical methods of metal extraction is normally used for those metals
Whose oxide/ore is not reduced by carbon
Which fall in the category of alkali & alkaline earth metals
Which stands higher in the electrochemical series of the metal
All (A), (B) & (C)
Ganister contains maximum percentage of
FeO
SiO2
MgO
MnO2
Presence of nickel & chromium in steel does not raise its
Elastic limit
Machining properties
Ductility
Resilience
Hooke's law
Applies to elastic deformation
Applies beyond limit of proportionality in stress-strain curve
States that stress is inversely proportional to strain upto elastic limit
None of these
Primary designation of steel is based on its
Hardness & tensile strength
Carbon content
Iron content
Alloying elements content
The noble metals
Are exemplified by Na, K and Li
Do not resist corrosion very strongly
Are the lowermost in the electro-chemical series of metals
None of these
For the Stoke's law to be valid in the case of a falling sphere in a fluid, the
Reynolds number (based on sphere diameter) should be < 1
Flow around the sphere should be in turbulent region
Sphere must be metallic
Fluid density should be constant
In case of condensers & evaporators operating under given terminal conditions, LMTD (logarithmic mean temperature difference) for counter flow as compared to that for parallel flow is
More
Less
Equal
Much more
Pick out the wrong statement.
For a pressure vessel to be classified as 'thin vessel', the ratio of wall thickness to mean radius is less than 0.1
For calculating forces and efficiency of riveted joint, either rivet diameter or rivet hole diameter is used in case of pressure vessel and in structural work
Longitudinal joint is normally made butt joint to maintain the circularity of the vessel
Maximum diameter of the opening provided in a pressure vessel, which does not require any compensation is 200 mm
Secondary hardening in steels arises out of the
Precipitation of fine alloy carbides at high temperatures
Refinement of ferrite grain size by working
Decomposition of retained austenite upon heat treatment
Precipitation of complex inter-metallic upon heat treatment
Water hammer is caused in steam carrying pipelines, because of
Partial condensation of steam
Vibration of the pipeline
High degree of superheat of steam
Its exposure to torrential rain
Pick out the wrong statement about coating/electroplating of metals.
Phosphate coating is used as an excellent base for paints & enamels
Phosphate coating is less corrosion resistant than chromate coating
The base metal to be electroplated is normally made the cathode of the electrolytic cell and coating metal is made the anode
Calorising is the process of coating steel with chromium