- a. Transmit torque from the driver to the impeller
- b. To convert kinetic energy into pressure energy
- c. To develop dynamic head
- d. Directing flow into and out of impeller
- e. Provide support to the bearing bracket
- f. Incorporate nozzles to connect suction & discharge piping.

- a. 120m
- b. 100m
- c. 80m
- d. 60m

- a. 14.3 m
- b. 4.3 m
- c. 4.8 m
- d. 14.8 m

- a. Cavitation occurs when NPSH available is less than the NPSH required by the pump.
- b. Cavitation is caused by the collapse of air bubbles in the suction side of the pump.
- c. Cavitation does not occur during part flow operation since available NPSH is high.
- d. Cavitation occurs only on the suction side of the impellers.
- e. Cast Iron impellers have the least ability to resist cavitation damage.

Description

- a. System Resistance Curve
- b. Friction Head
- c. Static Head
- d. Total Dynamic Head
- e. Head Capacity Curve
- f. Operating Point

- A. (a) - 2 (b) - 5 (c) - 4 (d) - 6 (e) - 1 (f) - 3
- B. (a) - 1 (b) - 4 (c) - 6 (d) - 5 (e) - 2 (f) - 3
- C. (a) - 2 (b) - 6 (c) - 4 (d) - 5 (e) - 1 (f) - 3
- D. (a) - 1 (b) - 4 (c) - 5 (d) - 6 (e) - 2 (f) - 3

- a. Radial flow
- b. Francis Vane
- c. Mixed Flow
- d. Axial Flow

- 1. c - b - a - d
- 2. a - d - b - c
- 3. d - a - b - c
- 4. b - a - d - c

- a) Throttling
- b) Connecting or disconnecting pump running in series or parallel
- c) Speed control

- a) Endurance Limit
- b) Corrosion Resistance
- c) Abrasive Wear Resistance
- d) Cavitation Resistance
- e) Casting and machining properties
- f) Tip speed
- g) Cost
- h) Working Pressure
- i) Galling Characteristics

- a) Gland Packing is easily installed.
- b) Gland Packing is cheaper than mechanical seal.
- c) Leakage tends to increase gradually giving early indication of impending failure.
- d) Gland Packing is less sensitive to the axial movement of shaft compared to mechanical seal.
- e) Gland Packing is easily replaced when the gland is split.

- a) Shaft Ultrasonic test
- b) Casing UTS, hardness test, chemical test
- c) Impeller - chemical analysis
- d) Impeller – dynamic balancing
- e) Casing - hydrostatic pressure test
- f) Pump - Performance test
- g) Pump - dimensional check
- h) NPSH test

The following is a list of the Test Reports as required by a user:

Please identify the QA document which contains the appropriate test report from the following options:

A. | B. |

C. | D. |

- a) Radial flow impeller
- b) Francis Vane impeller
- c) Mixed flow impeller
- d) Axial flow impeller

- 1. 72%
- 2. 75%
- 3. 81%
- 4. 83%

Can you place the correct efficiencies in the appropriate boxes?

Pump Size | Best efficiency duty point at 1480 rpm | Efficiency |
---|---|---|

A. 125x80-400 | 140 m3/hr, 50m | |

B. 125x100-400 | 190 m3/hr, 50m | |

C. 150x125-400 | 300 m3/hr, 50m | |

D. 200x150-400 | 450 m3/hr, 50m |

- a) A-1 B-2 C-3 D-4
- b) A-4 B-3 C-2 D-1
- c) A-3 B-1 C-2 D-4
- d) A-2 B-4 C-3 D-1

All the pumps generate the same head and impeller diameters are identical (400mm) - Why are the efficiencies different?

S/N | SPEED (RPM) | HEAD (m) | FLOW (Litre Per Sec) |
---|---|---|---|

1 | 1480 | 20 | 100 LPS |

2 | 1480 | 22 | 140 LPS |

3 | 1000 | 80 | 564 LPS |

4 | 1480 | 100 | 564 LPS |

- a) 1: 6HS14 2: 8HS10 3: 16HS32 4: 12HS23
- b) 1: 8HS12 2: 8HS12 3: 14HS32 4: 14HS26
- c) 1: 6HS12 2: 8HS12 3: 16HS32 4: 12HS23
- d) 1: 6HS10 2: 10HS12 3: 18HS25 4: 10HS22

- a) Same design capacity, head and impeller diameter
- b) Identical foot-print and installation interface dimensions
- c) Same materials of construction
- d) None of the above

- a) Optimum pump efficiency is wanted
- b) Lowest life cycle cost for the installation
- c) Highest reliability in a critical application
- d) Lowest environmental impact

- a) Smaller installation dimensions
- b) Ease of maintenance
- c) Absence of radial thrust load
- d) All of the above

- a) B is likely to be more efficient than A at the best efficiency point (design point)
- b) Shaft deflection at the stuffing box will be higher for B
- c) A will have lower axial thrust load
- d) B will have lower radial thrust load at part flow operation

Parameters | Pump model- 6x8-21 | Pump model- 8x10-14 |
---|---|---|

Rated capacity | 450 m3/hr. | 750 m3/hr. |

Rated head | 90 m | 36 m |

Impeller diameter | 540 mm | 360 mm |

Impeller width at outlet (including shrouds) | 40 mm | 76 mm |

Speed | 1480 rpm | 1480 rpm |

Type of casing | Single volute | Single volute |

Type of impeller | Double entry | Double entry |

- a) Axial thrust of 8x10-14 is likely to be greater than that of 6x8-21
- b) 6x8-21 is likely to be more efficient than 8x10-14
- c) Radial thrust at 50% flow will be more in case of 6x8-21
- d) None of the above

- a) Protect the shaft from abrasion and wear
- b) Increase the stiffness of the rotating element (shaft to be more precise)
- c) Reduce leakage losses through the stuffing box
- d) None of the above

- a) Total head developed by the pump is the sum of heads developed by each stage.
- b) The pump axial thrust is balanced because of two opposed single-entry impellers.
- c) The pump radial thrust is balanced because the volutes of two stages are at 1800 to each other.
- d) The total capacity of the pump is the sum of the flow through each stage.

- a) Packed gland pumps are preferred over mechanical seal fitted pumps in services such as fire protection where catastrophic failure of mechanical seals cannot be tolerated.
- b) Compared to a mechanical seal fitted pump, mechanical efficiency of a packed gland pump is lower.
- c) It's possible to reduce leakage to zero through a packed gland stuffing box.
- d) Packed gland pumps generally have shaft sleeves to protect the shafts from abrasive wear at the stuffing box.

- a) Diameter of the pump shaft depends mainly on the power absorbed (kW), speed of the pump and the permissible shear stress for the shaft material selected.
- b) Shaft stiffness factor (L3/D4) where L is the bearing span and D is the average shaft diameter is one of the measures of the shaft deflection.
- c) Keyways, threads and sharp changes of section are stress raisers in a pump shaft.
- d) A double volute pump needs shaft of larger diameter compared to a single volute pump.

- a) Pump casing plays an important role in the generation of dynamic head, same as the pump impeller.
- b) Thickness of the pump casing depends on the yield strength of the material used, permissible deflection, corrosion allowance required and the maximum test pressure.
- c) Single volute casing is easier to cast compared to a double volute casing.
- d) Casings are vulnerable to leakage, during pressure test, in areas where there are sharp changes of section.

- a) Impeller type, speed and outlet diameter.
- b) Impeller outlet vane angle, speed and outlet diameter.
- c) Impeller inlet and outlet diameter, speed and flow.
- d) None of the above.

Power absorbed is given by:

BkW = (Q×H×S.G.) / (3.67×efficiency)

Q – Flow rate in m^{3}/hr

H – Total Dynamic Head in meter water column (m)

S.G – Specific Gravity of the working fluid

- a) 30 m and 46 kW
- b) 32 m and 49 kW
- c) 35 m and 53.6 kW
- d) 30 m and 4.6 kW

- a) Brine (head = 192.5 ft, pressure = 100 psi) & kerosene (head = 288.7 ft, pressure = 100 psi)
- b) Brine (head = 231 ft, pressure = 83.3 psi) & kerosene (head = 231 ft, pressure = 100 ps)
- c) Brine (head = 231 ft, pressure = 120 psi) & kerosene (head = 231 ft, pressure = 80 psi)
- d) Brine (head = 192.5 ft, pressure = 120 psi) & kerosene (head = 208.7 ft, pressure = 80 psi)

- a) Q = 450 m
^{3}/hr., H= 81 m, η = 82% and power = 121 kW - b) Q = 405 m
^{3}/hr., H= 72.9 m, η = 73.8% and power = 109 kW - c) Q = 450 m
^{3}/hr., H= 72.9 m, η = 82% and power = 109 kW - d) Q = 405 m
^{3}/hr., H= 81 m, η = 82% and power = 109 kW

Capacity | 2400 m^{3}/hr. |

Head | 150 m |

Efficiency | 86% |

Speed | 1800 rpm |

Medium | Sea water (sp. gr. = 1.03) |

Driver | Main propulsion engine through power take-off and gear box |

The manufacturer can test pump at his works, using one of the test motors at six pole speed (1000 rpm synchronous). What will be the rated duty condition of the pump at 1000 rpm at the test bed and what should be the rating of the test- motor. Test bed uses clean cold water (sp. gr. = 1.0) for testing.

- a) Q = 1333 m
^{3}/hr., H = 83.3 m, motor = 400 kW, 6 pole - b) Q = 1333 m
^{3}/hr., H = 46.3 m, motor = 230 kW, 6 pole - c) Q = 740 m
^{3}/hr., H = 83.3 m, motor = 215 kW, 6 pole - d) Q = 740 m
^{3}/hr., H = 83.3 m, motor = 215 kW, 6 pole

Impeller- 5HS12 | Impeller- 6HS17 | Impeller- 6HS22 | Impeller- 8HS26 |

Q = 1110 US gpm | Q = 1760 US gpm | Q = 2200 US gpm | Q = 3170 US gpm |

H = 72 ft. | H = 180 ft. | H = 295 ft. | H = 460 ft. |

N = 1450 rpm | N = 1480 rpm | N = 1480 rpm | N = 1480 rpm |

- a)
Pump A 900 Pump B 975 Pump C 1263 Pump D 1954 - b)
Pump A 975 Pump B 1954 Pump C 1263 Pump D 840 - c)
Pump A 1954 Pump B 1263 Pump C 975 Pump D 840 - d)
Pump A 1263 Pump B 1954 Pump C 975 Pump D 900

Impeller- 5HS12 | Impeller- 6HS17 | Impeller- 6HS22 | Impeller- 8HS26 |

Q = 1110 US gpm | Q = 1760 US gpm | Q = 2200 US gpm | Q = 3170 US gpm |

H = 72 ft. | H = 180 ft. | H = 295 ft. | H = 460 ft. |

N = 1450 rpm | N = 1480 rpm | N = 1480 rpm | N = 1480 rpm |

- a)
Pump A 84% Pump B 81% Pump C 80.5% Pump D 79% - b)
Pump A 83% Pump B 78% Pump C 84% Pump D 80% - c)
Pump A 82% Pump B 84% Pump C 83% Pump D 75% - d)
Pump A 81% Pump B 67% Pump C 85% Pump D 72%

Pump A | Pump B | Pump C | Pump D |

Q = 2400 m^{3}/hr. |
Q = 1200 m^{3}/hr. |
Q = 600 m^{3}/hr. |
Q = 300 m^{3}/hr. |

H = 150 m | H = 140 m | H = 140 m | H = 140 m |

N = 1800 rpm | N = 1800 rpm | N = 1800 rpm | N = 2100 rpm |

The suction specific speed (N_{ss}) is given by
(N√Q)
/
((NPSHr)0.75)

where, N = speed in rpm, Q = flow/eye in US gpm and NPSHr is in ft.

Assuming that most commercially designed pumps achieve N_{ss} = 9000 (US units), what would be the expected NPSHr of pumps A, B, C & D if all of them are double suction split-case single

- a)
Pump A 17.2 m Pump B 10.8 m Pump C 6.8 m Pump D 5.3 m - b)
Pump A 10.8 m Pump B 6.8 m Pump C 4.3 m Pump D 3.3 m - c)
Pump A 6.4 m Pump B 4.1 m Pump C 2.5 m Pump D 2.0 m - d)
Pump A 4.3 m Pump B 6.8 m Pump C 10.8 m Pump D 3.3 m

Rated capacity of each pump - 600 m^{3}/hr

Rated head - 140 m

Static lift (minimum water level to pump center line) = 3.0 m

Total losses in the pipe line (strainer, bend, straight pipe, etc.) = 0.5 m

Vapor pressure = 0.6 m

Atmospheric pressure = 10.3 m

Available NPSH = (10.3 - 3.0 - 0.5 - 0.6) m = 6.2 m

The ship-owner wants to maintain a safety ratio of 1.2 (NPSH_{a}/NPSH_{r}) to prevent cavitation. What is the maximum speed at which he can run a) an end suction pump b) a double suction pump, considering that pumps operate at B.E.P for rated duties and that they have been designed for Nss = 9000 US units?

- a) End suction-2080 RPM & Double suction - 2080 RPM
- b) End suction-2080 RPM & Double suction - 1470 RPM
- c) End suction-1470 RPM & Double suction - 2080 RPM
- d) End suction-1677 RPM & Double suction - 2370 RPM

(Given, vapor pressure of water at pumping temperature is 0.5 m & suction vessel is open to atmospheric pressure.)

- a) 6.8 m
- b) 7.8 m
- c) 8.8 m
- d) 9.9 m

Type of Losses | Labels |
---|---|

A) Entrance Shock losses | 1 |

B) Mechanical losses | 2 |

C) Leakage loses | 3 |

D) Disk friction losses | 4 |

E) Casing hydraulic losses | 5 |

- a)
A 1 B 5 C 2 D 3 E 4 - b)
A 1 B 5 C 3 D 2 E 4 - c)
A 4 B 2 C 1 D 3 E 5 - d)
A 4 B 1 C 5 D 2 E 3

Head Figures |
---|

A) Static Head |

B) Friction head at duty point |

C) Total Head at duty point |

D) Friction head at 250 M3/Hr. |

E) Total Head at 750 M3/Hr. |

- a)
A 28M B 22M C 50M D 80M E 9M - b)
A 22M B 28M C 9M D 50M E 80M - c)
A 22M B 28M C 50M D 7M E 85M - d)
A 80M B 28M C 50M D 7M E 22M

System | Options |
---|---|

Boiler Feed Pump | A) |

Town Water Distribution | B) |

Heat Exchanger | C) |

Mine Dewatering | D) |