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

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
by

1 Answer

Answer :

(D) All the above
by

Related questions

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*

Description : 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*

Last Answer : e) all of the above*

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

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

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

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

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)

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)

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

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

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 from the periphery of the impeller and to transmit it to the delivery pipe at constant velocity (D) To increase the pump discharge rate

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

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

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

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

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

Last Answer : (C) Centrifugal

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)

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)

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

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

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) Discharge of water by a centrifugal pump being run at a constant rpm (B) Water flow in the suction and discharge pipe of a reciprocating pump (C) Water discharge from a vertical vessel in which constant level is maintained (D) Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe

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

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)

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

Pick up the correct statement from the following regarding radial flow centrifugal pumps: (A) These are provided with volute type or turbine type casings (B) In involute type of radial flow centrifugal pump, the impeller discharges into a gradually expanding spiral casing (C) The efficiency of turbine type of radial flow centrifugal pump, is always higher than that of volute type (D) All the above

Description : Pick up the correct statement from the following regarding radial flow centrifugal pumps:  (A) These are provided with volute type or turbine type casings  (B) In involute type of radial flow ... centrifugal pump, is always higher than that of  volute type  (D) All the above 

Last Answer : (D) All the above 

Why The Centrifugal Pump Is Called High Discharge Pump?

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

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

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

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)

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)

Pick up the correct statement from the following: (A) At a particular speed of operation, the head produced decreases with the increase of discharge (B) At zero discharge, discharge valve remaining closed, the head developed is maximum which is known as shut-off head (C) At a particular speed the discharge at which efficiency of a pump is maximum, is known as normal discharge (D) All the above

Description : Pick up the correct statement from the following: (A) At a particular speed of operation, the head produced decreases with the increase of discharge (B) At zero discharge, discharge valve remaining closed ... which efficiency of a pump is maximum, is known as normal discharge (D) All the above

Last Answer : (D) All the above

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)

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)

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

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

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) NPSH required (B) BHP required by the pump (C) Head of the liquid pumped (D) All (A), (B) and (C)

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)

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

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

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 pressure of the liquid at suction temperature (D) Discharge minus vapor pressure of the liquid at the discharge 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

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 pressure of the liquid at suction temperature (D) Discharge minus vapor pressure of the liquid at the discharge 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

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

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

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

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

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

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

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

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)

Priming in a distillation column (A) Results from very low gas velocity (B) Is desirable from point efficiency consideration (C) Is characterised by the presence of foam throughout the space between trays (D) Reduces the overall pressure drop

Description : Priming in a distillation column (A) Results from very low gas velocity (B) Is desirable from point efficiency consideration (C) Is characterised by the presence of foam throughout the space between trays (D) Reduces the overall pressure drop

Last Answer : (C) Is characterised by the presence of foam throughout the space between trays

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

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 

Propeller type centrifugal pumps are most suitable for (A) High capacity at high heads (B) High capacity at low heads (C) Low capacity at high heads (D) Low capacity at low heads

Description : Propeller type centrifugal pumps are most suitable for (A) High capacity at high heads (B) High capacity at low heads (C) Low capacity at high heads (D) Low capacity at low heads

Last Answer : (B) High capacity at low heads

Specific speed of a centrifugal pump relates it with another pump having the (A) Dynamic similarity (B) Same efficiency (C) Same speed (D) Geometrical similaritySpecific speed of a centrifugal pump relates it with another pump having the (A) Dynamic similarity (B) Same efficiency (C) Same speed (D) Geometrical similaritySpecific speed of a centrifugal pump relates it with another pumphaving the(A) Dynamic similarity(B) Same efficiency(C) Same speed(D) Geometrical similarity

Description : Specific speed of a centrifugal pump relates it with another pump having the (A) Dynamic similarity (B) Same efficiency (C) Same speed (D) Geometrical similaritySpecific speed of a centrifugal ... another pumphaving the(A) Dynamic similarity(B) Same efficiency(C) Same speed(D) Geometrical similarity

Last Answer : (A) Dynamic similarity

Various efficiencies of a centrifugal pump are related as (where, ηm = mechanical efficiency ηv = volumetric efficiency. ηma = manometric efficiency ηo = overall efficiency) (A) ηma × ηm × ηv = ηo (B) ηm = ηv . ηma (C) ηma = ηm × ηv (D) ηv = ηm × ηma

Description : Various efficiencies of a centrifugal pump are related as (where, ηm = mechanical efficiency ηv = volumetric efficiency. ηma = manometric efficiency ηo = overall efficiency) (A) ηma × ηm × ηv = ηo (B) ηm = ηv . ηma (C) ηma = ηm × ηv (D) ηv = ηm × ηma

Last Answer : (B) ηm = ηv . ηma

With increasing flow rate, the hydraulic efficiency of a centrifugal pump (A) Monotonically decreases (B) Decreases and then increases(C) Remains constant(D) Increases and then decreases

Description : With increasing flow rate, the hydraulic efficiency of a centrifugal pump (A) Monotonically decreases (B) Decreases and then increases (C) Remains constant (D) Increases and then decreases

Last Answer : (A) Monotonically decreases

In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the __________ efficiency. (A) Manometric (B) Mechanical (C) Volumetric (D) Overall

Description : In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the __________ efficiency. (A) Manometric (B) Mechanical (C) Volumetric (D) Overall

Last Answer : (A) Manometric

In case of a, centrifugal pump, the ratio h1/h2is termed as the __________ efficiency (where, h1 = actual measured head & h2 = head imparted to the fluid by impeller). (A) Mechanical (B) Overall (C) Volumetric (D) Impeller

Description : In case of a, centrifugal pump, the ratio h1/h2is termed as the __________ efficiency (where, h1 = actual measured head & h2 = head imparted to the fluid by impeller). (A) Mechanical (B) Overall (C) Volumetric (D) Impeller

Last Answer : A) Mechanical

The efficiency of a centrifugal pump is maximum when its blades are :

Description : The efficiency of a centrifugal pump is maximum when its blades are : (A) straight (B) bent forward (C) bent backward (D) bent forward first and then backward

Last Answer : The efficiency of a centrifugal pump is maximum when its blades are : bent backward

The maximum depth from which a centrifugal pump can draw water is (A) Dependent on the speed of the pump (B) Dependent on the power of the pump (C) 34 feet (D) 150 feet

Description : The maximum depth from which a centrifugal pump can draw water is (A) Dependent on the speed of the pump (B) Dependent on the power of the pump (C) 34 feet (D) 150 feet

Last Answer : (C) 34 feet

Reciprocating pumps (A) Are not suitable for variable heads (B) Are four times costlier than centrifugal pumps (C) Are not suitable for pumping water containing sediments (D) Single stroke produce pulsating flow

Description : Reciprocating pumps  (A) Are not suitable for variable heads  (B) Are four times costlier than centrifugal pumps  (C) Are not suitable for pumping water containing sediments  (D) Single stroke produce pulsating flow 

Last Answer : (A) Are not suitable for variable heads 

Multistage centrifugal pumps are generally used for (A) High head (B) Low head but high discharge (C) Highly viscous liquid (D) Slurries of high solid concentration

Description : Multistage centrifugal pumps are generally used for (A) High head (B) Low head but high discharge (C) Highly viscous liquid (D) Slurries of high solid concentration

Last Answer : (A) High head

For a reciprocating pump, the indicator diagram is the graph between the (A) Discharge and overall efficiency (B) Volume swept by piston for one complete revolution and the pressure in the cylinder (C) Angle swept by the crank pin at any instant and the discharge (D) None of these

Description : For a reciprocating pump, the indicator diagram is the graph between the (A) Discharge and overall efficiency (B) Volume swept by piston for one complete revolution and the pressure in the cylinder (C) Angle swept by the crank pin at any instant and the discharge (D) None of these

Last Answer : (B) Volume swept by piston for one complete revolution and the pressure in the cylinder

A double acting reciprocating pump compared to a single acting pump (of almost same size working under same pressure levels) would give almost double (A) Head (B) Discharge (C) Efficiency (D) None of these

Description : A double acting reciprocating pump compared to a single acting pump (of almost same size working under same pressure levels) would give almost double (A) Head (B) Discharge (C) Efficiency (D) None of these

Last Answer : (B) Discharge

Pump priming should be resorted to at a time of? (1) Inflation (2) Deflation (3) Stagflation (4) Reflation

Description : Pump priming should be resorted to at a time of? (1) Inflation (2) Deflation (3) Stagflation (4) Reflation

Last Answer : (2) Deflation Explanation: Pump priming is the action taken to stimulate an economy, usually during a recessionary/deflationary period, through government spending, and interest rate and tax reductions. ... the injection of funds, with the goal of prompting higher demand for goods and services.

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

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

Pump priming should be resorted to at a time of ? (1) Inflation (2) Deflation (3) Stagflation (4) Reflation

Description : Pump priming should be resorted to at a time of ? (1) Inflation (2) Deflation (3) Stagflation (4) Reflation 

Last Answer : Deflation

The percentage of water for making a cement paste of normal consistency varies from (a) 15 to 25% (b) 25 to 35% (c) 35 to 50% (d) 50 to 60%

Description : The percentage of water for making a cement paste of normal consistency varies from (a) 15 to 25% (b) 25 to 35% (c) 35 to 50% (d) 50 to 60%

Last Answer : (b) 25 to 35%

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

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

Cavitation in a centrifugal pump can be avoided by keeping the (A) Inlet pressure high (B) Outlet pressure low (C) Inlet pressure low (D) Outlet pressure high

Description : Cavitation in a centrifugal pump can be avoided by keeping the (A) Inlet pressure high (B) Outlet pressure low (C) Inlet pressure low (D) Outlet pressure high

Last Answer : (A) Inlet pressure high

09. According to Bazin, the coefficient of discharge varies with the height of water over the sill of a weir. A) Correct B) Incorrect

Description : 09. According to Bazin, the coefficient of discharge varies with the height of water over the sill of a weir. A) Correct B) Incorrect

Last Answer : A

Consider the following statements in respect of steady laminar flow through a circular pipe: 1. Shear stress is zero on the central axis of the pipe 2. Discharge varies directly with the viscosity of the fluid 3. Velocity is maximum at the centre of the pipe. 4. Hydraulic gradient varies as the square of the mean velocity of flow. Which of these statements are correct? (a) 1, 2 , 3 & 4 (b) 1 & 3 only (c) 2 & 4 only (d)3 & 4 only

Description : Consider the following statements in respect of steady laminar flow through a circular pipe: 1. Shear stress is zero on the central axis of the pipe 2. Discharge varies directly with the viscosity of the fluid 3. Velocity is maximum at the ... 2 , 3 & 4 (b) 1 & 3 only (c) 2 & 4 only (d)3 & 4 only

Last Answer : (b) 1 & 3 only

Consider the following statements: Mitra’s hyperbolic transition design is based on the principle that : 1. Flow depth in the canal, as well as the discharge, is constant 2. width of the canal varies along with the discharge 3. Rate of change of velocity per unit length of transition is constant throughout the length of the transition. Which of these statements are correct ? a) 1, 2 and 3 b) 1 and 2 only c) 2 and 3 only d) 1 and 3 only

Description : Consider the following statements: Mitra's hyperbolic transition design is based on the principle that : 1. Flow depth in the canal, as well as the discharge, is constant 2. width of the canal varies along with the discharge 3. Rate ... a) 1, 2 and 3 b) 1 and 2 only c) 2 and 3 only d) 1 and 3 only

Last Answer : d) 1 and 3 only