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WorksheetsME LAB 2
Total questions: 30
Worksheet time: 15mins
A single acting, twin cylinder, Ammonia compressor with bore equal to stroke is driven by
an engine at 250 rpm. The machine is installed in a chilling plant to produce 700 kW of
refrigeration at -18°C evaporating temperature. At this temperature the cooling effect per kg
mass is 1160 kJ. The specific volume of vapor entering the compressor is 0.592 m3 per kilogram.
Assume 85% volumetric efficiency, determine the bore in mm.
A. 400 mm
B. 300 mm
C. 450 mm
D. 500 mm
A 150 Hp motor is used to drive the compressor. If the heat loss from the compressor is 25
kW and the mass flow rate of the refrigerant entering the compressor is 0.50 kg/s, determine
the difference of the enthalpies between the inlet and outlet of the compressor.
A. 143.80 kJ/kg
B. 153.80 kJ/kg
C. 173.80 kJ/kg
D. 183.80 kJ/kg
A single acting air compressor with a clearance of 6% takes in air at atmospheric pressure
and temperature of 85°F and discharges it at a pressure of 85 psia. The air handled is 0.25
ft3 /cycle measured at discharge pressure. If the compression is isentropic, find the piston
displacement per cycle, if the compressor is running at 750 rpm.
A. 0.0750 ft3 /cycle
B. 0.025 ft3 /cycle
C. 1.030 ft3 /cycle
D. 1.090 ft3 /cycle
A water tube boiler has a capacity of 1000 kg/hr of steam. The factor of evaporation is 1.3,
boiler rating is 200%, boiler efficiency is 65% and heating surface area is 0.91 m2 per bo.Hp. And
the heating value of fuel is 18,400 kCal/kg. The total coal available in the bunker is 50,000 kg.
Determine the no. of hrs. to consume the available fuel.
A. 853.36 hrs
B. 706.57 hrs
C. 979.46 hrs
D. 100.75 hrs
The heating value of fuel supplied in a boiler is 40,000 kJ/kg. If the factor of evaporation is
1.10 and the actual specific evaporation is 10, what is the efficiency of the boiler?
A. 62.07%
B. 53.08%
C. 78.05%
D. 54.97%
The ____ valve protect the fuel oil lines and pump from excessive pressure.
A.Safety
B.Relief
C.Bypass
D.Stop
Regardless of the type of fuel oil used the fuel oil must be _____ before it enters the boiler furnace.
A.Pressurized
B.Treated
C.Atomized
D.Measured
The ______ of fuels oil is the lowest temperature at which it will flow as a liquid.
A.Fire point
B.Pour point
C.Flash point
D.Viscosity
A leak on the fuel oil suction line between the tank and the suction side of the fuel oil pump would result in :
A.The suction gauge pulsating
B.Air entering the suction line
C.Pulsating of the fire in the boiler
D.All of the above
At 0 psig, how many BTU are necessary to change 1 lb of water at 212⁰F of steam?
A.144
B.970
C.180
D.1190
Steam at 100 psi and 400⁰F is :
A.Saturated
B.Superheater
C.Wet
D.None of the above
Increasing the pressure has what effect of the boiling point of water?
A.No change
B.Temperature will be raised
C.Temperature will be lowered
D.Temperature will be increase 2 ⁰F for every psi
Heat absorbed by water when it changes from liquid to steam at the boiling point is called:
A.Sensible heat
B.Specific heat
C.Latent heat
D.Superheater
Heat may be transferred in how many ways?
A.One
B.Three
C.Two
D.Four
Condensate from the nonreturn steam trap is pumped from the condensate return tank of the :
A.Return tank
B.Feed water heater
C.Vacuum tank
D.Boiler
Excessive use of cold city water makeup reduces overall efficiency because the water must be _____ before use in the boiler.
A.Vented
B.Filtered
C.Heated
D.Recirculated
Water added to the boiler to replace water lost due to leaks and blowing down is known as ____ water.
A.Extra
B.Boiler
C.Makeup
D.Feed
The vacuum pump pumps water and discharges air to the :
A.Expansion tank
B.Return valve
C.Compression tank
D.Atmosphere
According to the ASME code, safety valves on low pressure boilers should be tested by hand at least:
A.Once a month
B.Once a year
C.Once a shift
D.Twice a year
What pressure gauge that reads more pressure than is actually in the boiler.
A.Broken
B.Uncalibrated
C.Slow
D.Fast
Impurities that build up on the surface of the water in the boiler prevent ___ from breaking through the surface of water.
A.Air
B.CO
C.Oxygen
D.Steam
What pressure gauge that can read weather vacuum pressure or not.
A.Compound
B.Suction
C.Duplex
D.Vacuum
Which of the following will make a boiler work more efficiency?
A.More fuel added
B.Firetube are decreases in size
C.The heating surface is increased
D.All of the above
A ______ boiler has heat and gases of combustion that pass through tubes surrounded by water.
A.Fire tube
B.Cast iron sectional
C.Water tube
D.Straight-tube
A _______ boiler has water in the tube and heat gases of combustion passing around the tubes
A.Fire tube
B.Cast iron sectional
C.Water tube
D.Firebox
It is the part of the boiler with water on one side and heat on the other side.
A.Furnace volume
B.Fire side
C.Heating surface
D.Water side
Which of the following is necessary to generate steam in a boiler?
A.A container
B.Heat
C.Water
D.All of the above
The function of the steam boiler is to _______.
A.Produce condensate
B.Create heat
C.Produce steam
D.Burn fuel
At what temperature will water normally turns to steam?
A.100⁰F
B.200 ⁰F
C.150 ⁰F
D.212 ⁰F
The steam pressure gauge on the boiler is calibrated to read in:
A.Inches of vacuum
B.Absolute pressure
C.Pounds per square inch
D.Pressure below atmospheric pressure
