Compressor, Pneumatic components and Accessories in fluid System
1. The ratio of work-done per cycle to the stroke volume of the compressor is known as.......
A.Compressor capacity
B.Compression ratio
C.Compressor efficiency
D.Mean effective pressure
2. The capacity of a compression is 10 m3/minute.10 m 3/minute refers to.......
A.Standard air
B.Free air
C.Compressed air
D.Compressed air at delivery pressure
3. Aeroplanes employe following type of compressor.........
A.Radial flow
B.Axial flow
C.Centrifugal
C.Combination of above
4. The multi stage compression as compared to single stage compression......
A.Improves volumetric efficiency for the given pressure ratio
B.Reduces work done per kg of air
C.Reduces cost of compressor
D.Gives more uniform torque
E.All of the above
5. Compression efficiency is compared against.......
A.Ideal compression
B.adiabatic compression
C.both isothermal and adiabatic compression
D.Isentropic compression
E.Isothermal compression
6. The volume of air delivered by the compressor is called.......
A.Free air delivery
B.Compressor capacity
C.Swept volume
D.None of the above
7. The most efficient method of compressing air is to compress it.......
A.Isothermal
B.Adiabatically
C.Isentropically
D.Isochronically
8. Ratio of indicated HP and break HP is known as.........
A.Mechanical efficiency
B.Volumetric efficiency
C.Isothermal efficiency
C.Adiabatic efficiency
9. Maximum work is done in compressing air when the compression is......
A.Improves volumetric efficiency for the given pressure ratio
B.Isothermal
C.Adiabatic
D.Polytropic
E.Any of the above
10. The value of air sucked by the compressor during its suction stroke is called.......
A.Free air delivery
B.Compressor capacity
C.Swept volume
D.none of the above
11. The ratio of indicated HP to shaft HP is known as.......
A.Compressor efficiency
B.Isothermal efficiency
C.Volumetric efficiency
D.Mechanical efficiency
12. Volumetric efficiency is.......
A.The ratio of stroke volume to clearance volume
B.The ratio of the air actually delivered to the amount of piston displacement
C.Reciprocal of compression ratio
D.Index of compressor performance
13. Volumetric efficiency of air compressors is of the order of.........
A.20 to 30%
B.40 to 50%
C.60 to 70%
D.70 to 90%
14. The pressure of air at the beginning of the compression stroke is......atmospheric pressure
A.Equal to
B.Less than
C.More than
D.None of the above
15. The intercooling in multistage compressors is done.......
A.To cool the air during compression
B.To cool the air at delivery
C.To enable compression in two stages
D.To minimise the work of compression
16. Mining industry usually employs following motive power.......
A.AC electric motor
B.Compressed air
C.Petrol engine
D.Diesel engine
17. Ratio of compression is the ratio of.......
A.Gauge discharge pressure to the gauge intake pressure
B.Absolute discharge pressure to the absolute intake pressure
C.Stroke Volume and clearance volume
D.None of the above
18. Cylinder clearance in a compression should be .........
A.As large as possible
B.As small as possible
C.about 50% of sweet volume
C.About 100% of swept volume
19. Separators are generally installed in compressors......
A.After the intercooler
B.Before the intercooler
C.Before the receiver
D.After the intercooler
20. Euler's equation is applicable for .......
A.Centrifugal compressor
B.Axial compressor
C.Pumps
D.All of the above
21. Volumetric efficiency of a compressor with clearance volume.......
A.Volumetric efficiency of a compressor with clearance volume
B.Decreases with increase in compression ratio Compressed air
C.In not dependent upon compression ratio
D.May increase or decrease depending on compressor capacity
22. Volumetric efficiency of a compressor without clearance volume.......
A.Increases with increase in compression ratio
B.Decreases with increase in compression ratio
C.In not dependent upon compression ratio
D.May increase or decrease depending on compressor capacity
23. The clearance volume of the air compressor is kept minimum because .........
A.It allows maximum compression to be achieved
B.It greatly affects volumetric efficiency
C.It results in minimum work
D.It permits isothermal compression
24. Compressor mostly used for supercharging of IC engines is ......
A.Radial flow compressor
B.Axial from compressor
C.Roots blower
D.Reciprocating compressor
25. The rotary compressors are used for delivering.......
A.Small quantities of air at high-pressure
B.Large quantities of air at high-pressure
C.Small quantities of air at low pressures
D.Large quantities of air at a low pressures
26. The maximum delivery pressure in a rotary air compression is.......
A.10 bar
B.20 bar
C.30 bar
D.40 bar
27. The speed of the rotary compressor is.......as compared to reciprocating air compressor
A.High
B.Low
C.Equal
D.None of the above
28. The type of rotary compressor used in gas turbine is of .......
A.Centrifugal type
B.Axial flow type
C.Radial flow type
D.None of this
29. The positive displacement compressor is.......
A.Roots blower compressor
B.Centrifugal compressor
C.Axial flow compressor
D.Vane blower compressor
E.Both A and D
30. If the flow of air through the compressor is perpendicular to its axis,then it is a.......
A.Reciprocating compressor
B.Centrifugal compressor
C.Axial flow compressor
D.Turbo compressor
31. In an axial flow compressor,the ratio of pressure in the rotor blades to the pressure rise in the compressor in one stage is known as.........
A.Work factor
B.Slip factor
C.Degree of reaction
C.Pressure coefficient
32. Reciprocating air compressor is best suited for......
A.Large quantity of air at high pressure
B.Small quantity of air at high pressure
C.Small quantity of air at low pressure
D.Large quantity of air at low pressure
33. Rotary compressor is best suited for.......
A.Large quantity of air at high pressure
B.Small quantity of air at high pressure
C.Small quantity of air at low pressure
D.Large quantity of air at low pressure
34. During peak load periods,the best method of controlling compressors is.......
A.Start-stop motor
B.Constant speed unloader
C.Relief valve
D.Variable speed
35. In a centrifugal compressor,an increase in speed at a given pressure ratio causes.......
A.Increase in flow
B.Decrease in flow
C.Increase in efficiency
D.Decrease in efficiency
E.Increase in flow and decrease in efficiency
36. The volumetric efficiency of a compressor.......
A.Increases with decrease in compression ratio
B.Decreases with decrease in compression ratio
C.Increases with increase in compression ratio
D.Decrease with increase in compression ratio
37. The ratio of the indicated power to the shaft power or brake power of the motor or engine required to drive the compressor,is called......
A.Compressor efficiency
B.Volumetric efficiency
C.Isentropic efficiency
D.Mechanical efficiency
38.Reciprocating compressor is a ______
A. Positive Displacement
B.Dynamic
C.Negative Displacement
D.None of the above
39. Which of the following is not a type of Rotary compressor?
A.Roots Blower
B.Sliding Vane
C.Liquid Ring
D.Diphragm
40. Which of the following is type of Dynamic compressor?
A.Roots Blower
B.Axial
C.Liquid Ring
D.Diphragm
41. How much strokes are there in positive displacement reciprocating compressor?
A.Two
B.One
C.Four
D.Six
42. What is the function of intercooler in any Two stage Compressor?
A.To avoid vibrations
B.To compress Air
C.To provide continuous flow of air
D.To reduce the temprature of air from single stage to another
43. Twin screw compressor is used to generate air pressure ___
A.Below 50 Bar
B.Upto 100 bar
C.Below 10 Bar
D.upto 500 Bar
44. Pressure Ratio of Vane compressor is ___
A.6.0
B.2.0
C.9.0
D.8.0
45. Twin screw compressor is used to generate air pressure ___
A.Below 250 Bar
B.Upto 300 bar
C.Below 10 Bar
D.upto 3 Bar
46. Twin screw compressor has air pressure____ than reciprocating compressor
A.More
B.Less
C. Equal
D.None
47. Lobe compressor is a ______
A.Positive Displacement
B.Dynamic
C.Negative Displacement
D.None of the above
48. Lobe compressor is used to generate air pressure ___
A.Below 60 Bar
B.Upto 2 bar
C.Below 10 Bar
D.upto 50 Bar
49. Compression Ratio of lobe compressor is ___
A.5.6
B.2.1
C.1.7
D.2.5
50. Centrifugal compressor is a ______
A.Positive Displacement
B.Dynamic
C.Negative Displacement
D.None of the above
51. Blower is also known as ______ compressor
A.Rotary
B.Centrifugal
C.Axial
D.Two stage
52. Axial compressor is a ______
A.Dynamic
B. Positive Displacement
C.Negative Displacement
D.None of the above
53. Pressure Ratio of lobe compressor is ___
A.5.6
B.2.0
C.1.7
D.2.5
54. When pressure is above 10 bar and upto 15 Bar then use ____
A.Multistage Reciprocating compressor
B.Twin screw compressor
C. Lobe compressor
D.Vane compressor
55. When pressure is between 7 to 15 Bar then use ____
A.Multistage Reciprocating compressor
B.Twin screw compressor
C. Lobe compressor
D.Vane compressor
56. When pressure is upto 3 Bar then use _____
A.Multistage Reciprocating compressor
B.Twin screw compressor
C. Lobe compressor
D.Vane compressor
57. Single acting compressor is more _____ than Double acting cylinder
A.Costly
B.Compact
C. Heavy
D.Efficient
58. What is the function of air receiver ?
A.To compress the air
B. To store the compressed air
C. To lubricate the compressed air
D.To expand the air before compression
59. FRL stands for
A.Fluctuating Regulator & Lubricator
B.Fluid Regulation of Lubricator
C. Filter, Regulator & Lubricator
D.None of the above
60. Dryer is used to
A.To avoid vibrations
B.To compress Air
C.To provide continuous flow of air
D.To remove the moisture from the compressed air
61. Lubricator is used to
A.Spray lubricating oil into compressed air
B.To compress Air
C.To provide continuous flow of air
D.To remove the moisture from the compressed air
62. FCV is used to control
A.Speed
B.Pressure
C.Direction
D.moisture
63. DCV is used to control
A.Speed
B.Pressure
C.Direction
D.moisture
64. PCV is used to control
A.Speed
B.Pressure
C.Direction
D.moisture
65. Select the PCV from the following
A.Check Valve
B. Relief valve
C.Shuttle Valve
D.3/2 Valve
66. To prevent the back pressure due to choking which valve will you use?
A. Relief valve
B.Check Valve
C. Shuttl Valve
D.Pressure regulator
67. Double check valve is also called as
A.Pilot operated Valve
B. Relief valve
C.Shuttle Valve
D.3/2 Valve
68. Which of the following material is not used t make the Hydraulic pipe
A.Steel
B. Copper
C.Auminium
D.Chrome
69. Positive seals allow small amount of leakage from them.
A.True
B. False
70. Non- positiive seals allow small amount of leakage from them.
A.True
B. False
71. ____ seals are those which are used to seal two mating parts which are having relative motion between them
A.Static
B. Dynamic
C.Positive Seal
D.Non positive seal
72. O ring seal is used as _____ seal
A.Static
B. Dynamic
C.Positive Seal
D.Dynamic as well as static
73. V ring seal is used in _____ system
A.Hydraulic
B. Pneumatic
C.Both
D.None of the above
74. To redue the noise level from copressor what will you use?
A.Heater
B. Muffler
C.Filter
D.None of the above
75. Which fitting is not used in Pneumatic pielines
A.Bell mouth tube
B. Compression
C.Screwed connection
D.Press mated
76. Which of the following systems generate more energy when used in industrial applications?
a.hydraulic systems
b.pneumatic systems
c.both systems generate same energy
d.cannot say
ANSWER: a. hydraulic systems
77.Which type of compressor requires a reservoir for compressed air and why?
a.rotary compressor to avoid pulsating effect
b.reciprocating compressor to avoid pulsating effect
c.both rotary and reciprocating compressors to avoid pulsating effect
d.none of the above
ANSWER: b. reciprocating compressor to avoid pulsating effect
78.Which of the following factors is considered while selecting a compressor?
a.type of oil filter required
b.volumetric efficiency
c.viscosity of the liquids used
d.all the above
ANSWER: b. volumetric efficiency
79.Where is an intercooler connected in a two stage compressor?
a.intercooler is connected after the two stage compressor
b.intercooler is connected between the two stages of the compressor
c.intercooler is connected before the two stage compressor
d.none of the above
ANSWER: b. intercooler is connected between the two stages of the compressor
80.Which valve is also known as memory valve?
a.Single pilot signal valve
b.double pilot signal valve
c.roller lever valve
d.logic valve
ANSWER: b. double pilot signal valve
81.Which of the following is a gas charged accumulator?
a.bladder type
b.spring loaded accumulator
c.weighted accumulator
d.all the above
ANSWER: a. bladder type
82.Which of the following gas is used in gas charged accumulator?
a.oxygen
b.nitrogen
c.carbon dioxide
d.all the above
ANSWER: b. nitrogen
83.Intensifier used in pneumatic systems has output pressure
a.less than input pressure
b.more than input pressure
c.same as input pressure
d.none of the above
ANSWER: b. more than input pressure
84.Function of muffler in Pneumatic system is
a.To increase the noise of compressed air
b.To Reduce the noise of compressed air
c.both a and b
d.None of the above
Answer: b
85.The seals prevents even a minute amount of fluid leakage is called
a.Positive seal.
b.Non Positive seal
c.Static seal
d.Dynamic seal
Answer: a
86.The seals are used between the surfaces of moving hydraulic parts is
a.Positive seal.
b.Non Positive seal
c.Static seal
d.Dynamic seal
Answer: d
87.Schedule no. of pipe is related to
a.Pressure
b.Temperature
c.Wall thickness
d.None of the above
Answer: C
88.Shuttle valve is known as
a.AND gate valve
b.NOR gate valve
c.OR gate valve
d.None of the above.
Answer: c
89.When only a portion of the oil is passed through the filter is known as
a.Surface filter
b.Depth filter
c.Full flow filter
d.By pass filter
Answer: d
