The main drawback of centrifugal pump is  
 a)necessity of priming
b) discharge from pump varies with the load of water
c) For high heads efficiency is low up to 50%  
d) the suction lift is limited to 6 metre
e) all of the above*

1 Answer

Answer :

e) all of the above*

Related questions

Description : The main draw-back of centrifugal pump, is (A) Necessity of priming (B) Discharge from pump varies with the load of water (C) For high heads, efficiency is low up to 50% (D) All the above

Last Answer : (D) All the above

Description : A centrifugal pump loses prime after starting. The reason of this trouble may be (A) Incomplete priming (B) Too high a suction lift (C) Low available NPSH and air leaks in the suction pipe (D) All (A), (B), and (C)

Last Answer : (D) All (A), (B), and (C)

Description : Foot valves are provided in the suction line of a centrifugal pump to (A) Avoid priming, every time we start the pump (B) Remove the contaminant present in the liquid (C) Minimise the fluctuation in discharge (D) Control the liquid discharge

Last Answer : (A) Avoid priming, every time we start the pump

Description : Function of air vessel provided in a reciprocating pump is to (A) Reduce discharge fluctuation (B) Reduce the danger of cavitation (C) Avoid the necessity of priming (D) Increase the pump efficiency

Last Answer : (A) Reduce discharge fluctuation

Description : If the discharge of a centrifugal pump is throttled, then its suction lift (A) Increases (B) Decreases (C) Remains unchanged (D) Data insufficient to predict

Last Answer : (A) Increases

Description : In case of unsteady fluid flow, conditions & flow pattern change with the passage of time at a position in a flow situation. Which of the following is an example of unsteady flow? (A) ... level is maintained (D) Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe

Last Answer : (B) Water flow in the suction and discharge pipe of a reciprocating pump

Description : Maximum theoretical suction lift for water at 15°C by a centrifugal pump is 34 ft. The same for water at 90°C will be __________ ft. (A) 40 (B) 34 (C) 8 (D) 37

Last Answer : (C) 8

Description : The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the (A) Discharge (B) Suction (C) Suction minus vapor ... of the liquid at suction temperature (D) Discharge minus vapor pressure of the liquid at the discharge temperature

Last Answer : (C) Suction minus vapor pressure of the liquid at suction temperature

Description : The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the (A) Discharge (B) Suction (C) Suction minus vapor ... of the liquid at suction temperature (D) Discharge minus vapor pressure of the liquid at the discharge temperature

Last Answer : (C) Suction minus vapor pressure of the liquid at suction temperature

Description : Horsepower requirement for given pump capacity depends upon the (A) Specific gravity of the liquid (B) Suction lift (C) Discharge head (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : The excess of the sum of pressure & velocity heads over the vaporpressure of the liquid at the suction is called the (A) Static submergence (B) Net positive suction head (NPSH) (C) Cavitation sensitivity (D) Priming

Last Answer : (B) Net positive suction head (NPSH)

Description : Circulation pump is located below the evaporator to (A) Avoid cavitation (B) Avoid frequent priming (C) Create more suction head (D) None of these

Last Answer : (C) Create more suction head

Description : What causes cavitation in centrifugal pump? (A) High suction pressure (B) Low barometric pressure (C) Low suction pressure (D) High suction velocity

Last Answer : (C) Low suction pressure

Description : Specific yield of well is a) Discharge per unit time b) Yield of well per metre of drawdown* c) Velocity of water per unit time d)None of the above

Last Answer : b) Yield of well per metre of drawdown*

Description : Consider the following statements: The total head against which a pump has to work must include, besides any other items, 1. the suction lift. 2. the delivery head. 3. the head lost due to friction at entrance in the rising main. 4. the ... 2 & 3 only (b) 2 & 3 only (c) 1, 2, 3 & 4 (d) 3 & 4 only

Last Answer : (c) 1, 2, 3 & 4

Description : Self-priming centrifugal pump can be used for (A) Booster service (B) Pumping liquid fertilisers (e.g. liquid NH3 ) (C) Pumping industrial wastes (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : Centrifugal pumps as compared to reciprocating pumps (A) Run at a lower speed for the same discharge (B) Do not need priming (C) Deliver fluid with pulsating/fluctuating discharge (D) Can be run with discharge line valve closed for a short interval

Last Answer : (D) Can be run with discharge line valve closed for a short interval

Description : Which of the following is not the function of a volute casing provided in a centrifugal pump? (A) To reduce the head loss in discharge (B) To increase the pump efficiency (C) To collect liquid ... and to transmit it to the delivery pipe at constant velocity (D) To increase the pump discharge rate

Last Answer : Option D

Description : Priming of a centrifugal pump is done to (A) Increase the mass flow rate of fluid (B) Develop effective pressure rise by the pump (C) Avoid chances of separation inside the impeller (D) None of these

Last Answer : (C) Avoid chances of separation inside the impeller

Description : Priming is needed in a __________ pump. (A) Reciprocating (B) Gear (C) Centrifugal (D) Diaphragm

Last Answer : (C) Centrifugal

Description : What type of pump may be appropriate for a liquid near saturation, a low flow rate, and very limited NPSHa (net positive suction head available)?

Last Answer : This application is nearly perfect for a turbine regenerative type of pump. Factors that immediately identify your application and pump type are the small flowrate, low NPSHa, and high temperature. The ... in pressure. You can visit the site below to learn more about these types of pumps.

Description : Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have (A) Very low speeds (B) Smaller discharge (C) Higher capital &maintenance cost (D) High vibrations

Last Answer : (C) Higher capital &maintenance cost

Description : Suction lift of a pump depends upon  (A) Atmospheric pressure  (B) Water temperature  (C) Velocity of water in suction pipe  (D) All the above 

Last Answer : (D) All the above 

Description : For a homogeneous earth dam 50 m high having 2 m free broad, a flow net was constructed and the results were : Number of potential drops = 2.4 Number of flow channels = 0.4. If co-efficiency of permeability of the dam material is ... 24 10-3 m3 /sec (C) 6 10-5 m3 /sec (D) 24 10-5 m3 /sec

Last Answer : (D) 24 × 10-5 m3 /sec

Description : Specific speed of a centrifugal pump depends upon the __________ head. (A) Suction (B) Delivery (C) Manometric (D) None of these

Last Answer : (D) None of these

Description : Net positive suction head (NPSH) of a centrifugal pump must be (A) Greater than the vapour pressure of the liquid (B) Less than the vapour pressure of the liquid (C) Equal to the vapour pressure of the liquid (D) Less than barometric pressure

Last Answer : (A) Greater than the vapour pressure of the liquid

Description : In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature. (A) Lower than (B) Higher than (C) Equal to (D) None of these

Last Answer : (B) Higher than

Description : Cavitation occurs in a centrifugal pump when the suction pressure is (A) Less than the vapour pressure of the liquid at that temperature (B) Greater than the vapour pressure of the liquid at that temperature (C) Equal to the vapour pressure (D) Equal to the developed head

Last Answer : (A) Less than the vapour pressure of the liquid at that temperature

Description : Conversion of dynamic velocity head into static pressure head in a centrifugal pump is the result of : (a) Increasing area of flow between adjacent vanes from inlet to outlet (b) Difference in pressure between suction and delivery ends (c) Radial thrust in pumps (d) Stuffing Box

Last Answer : (b) Difference in pressure between suction and delivery ends

Description : What is the maximum theoretical suction lift (metres) of a reciprocating pump? (A) 5 (B) 10(C) 50 (D) 100

Last Answer : (B) 10

Description : RBG loading caters for maaaaximum axle load of…….tones for locomotive with trailing loadof…… tonnes/metre of track with maximum axle load of…….tonnes for wagons a)22.9,7.67,25 b)22.5,7.67,22.9* c)25,7.67,22.9, d)None of above

Last Answer : b)22.5,7.67,22.9*

Description : GML loading caters for maaaaximum axle load of…….tonnes for locomotive with trailing load of………tonnes/metre. a)22.9,7.67* b)22.5,7.67 c)25,7.67 d)None of above

Last Answer : a)22.9,7.67*

Description : In areas where there is severe corrosion Finishing coat will be a) Two coats of aluminium paint to IS : 2339* b) One coat of zinc chromate priming to IS : 104 e) Two cover coats of red oxide paint to IS :123 f) One coat of zinc chrome - red oxide priming to IS : 2074

Last Answer : a) Two coats of aluminium paint to IS : 2339*

Description : For centrifugal pumps  (A) Initial cost is low  (B) Limited space is required  (C) The discharge obtained is steady and non-pulsating  (D) All the above 

Last Answer : (D) All the above 

Description : A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump. (A) Sump (B) Volute (C) Vacuum (D) Submerged

Last Answer : (C) Vacuum

Description : Capacity of a rotary gear pump can be varied by (A) Changing the speed of rotation (B) Bleeding air into suction (C) Bypassing liquid from the suction or discharge line (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : Consider the following statements: Air vessels are fitted on the suction and delivery sides of a reciprocating pump to 1. Achieve higher speed without separation. 2. Reduce work in overcoming frictional resistance. 3. Avoid excessive vibration ... 2 & 3 only (c) 2, 3 & 4 only (d) 1, 2, 3 & 4

Last Answer : (d) 1, 2, 3 & 4

Description : In areas where there is no severe corrosion Finishing coat will be a) Two coats of aluminium paint to IS : 2339 b) One coat of zinc chromate priming to IS : 104 c) Two cover coats of red oxide paint to IS :123* d) One coat of zinc chrome - red oxide priming to IS : 2074

Last Answer : c) Two cover coats of red oxide paint to IS :123*

Description : If w is the weight of water per cubic metre, Q is the discharge in cubic metres per sec and H is the total head, the required water horse power of the pump, is (A) wQH/15 (B) wQH/360 (C) wQH/220 (D) wQH/550

Last Answer : (A) wQH/15

Description : Why The Centrifugal Pump Is Called High Discharge Pump?

Last Answer : Centrifugal pump is a kinetic device. The centrifugal pump uses the centrifugal force to push out the fluid. So the liquid entering the pump receives kinetic energy from the rotating impeller. The centrifugal ... following formulae: Centrifugal force F= (M*V2)/R. Where, M-Mass V-Velocity R-Radius

Description : The depth of the water table at a place is 45 m below the general ground level. To lift water from a  deep tube well in such a locality, the type of pump to be installed is  (A) Centrifugal pump  (B) Reciprocating pump  (C) Deep well turbine pump  (D) None of these 

Last Answer : (C) Deep well turbine pump

Description : With a constant diameter impeller of a centrifugal pump (A) Its capacity varies directly as the square of speed (B) Head varies as the square of speed (C) Horsepower input varies as the square of speed (D) Head varies as the speed

Last Answer : (B) Head varies as the square of speed

Description : At a constant speed of the centrifugal pump, it’s __________ the impeller diameter. (A) Capacity varies directly with (B) Head varies as the square of (C) Horsepower varies as the cube of (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : Check in a centrifugal pump is (A) Provided in the discharge line (B) Generally a globe valve (C) Provided to prevent liquid from backing up through the pump when the pump is turned off or accidently stops running (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : Volute type of casing is provided in a centrifugal pump to (A) Convert velocity head to pressure head (B) Convert pressure head to velocity head (C) Reduce the discharge fluctuation (D) Increase the discharge

Last Answer : (D) Increase the discharge

Description : Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases. (A) ... the pump (C) Head of the liquid pumped (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : Check valve provided in the discharge line of a centrifugal pump serves the purpose of controlling the (A) Back flow of fluid in the event of stoppage of pump (B) Discharge pressure (C) Flow of liquid during operation of the pump (D) All (A), (B) and (C)

Last Answer : (A) Back flow of fluid in the event of stoppage of pump

Description : To handle smaller quantity of fluid at higher discharge pressure, use a __________ pump. (A) Reciprocating (B) Centrifugal (C) Volute (D) Rotary vacuum

Last Answer : (A) Reciprocating

Description : A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the new discharge will be __________ litres/minute. (A) 500 (B) 200 (C) 1000 (D) 750

Last Answer : (A) 500

Description : Which of the following is most prone to pulsating discharge flow? (A) Centrifugal pump (B) Reciprocating pump (C) Gear pump (D) Axial flow pump

Last Answer : (C) Gear pump