While starting a centrifugal pump, its delivery valve should be kept (A) Opened (B) Closed (C) Either opened or closed; it does not make any difference (D) Either opened or closed; depending on the fluid viscosity

While starting a centrifugal pump, its delivery valve should be kept
(A) Opened
(B) Closed
(C) Either opened or closed; it does not make any difference
(D) Either opened or closed; depending on the fluid viscosity
by

1 Answer

Answer :

(B) Closed
by

Related questions

While starting an axial flow pump, its delivery valve should be kept (A) Open (B) Closed (C) Either open or closed (D) None of these

Description : While starting an axial flow pump, its delivery valve should be kept (A) Open (B) Closed (C) Either open or closed (D) None of these

Last Answer : (A) Open

Erosion and pits formation on the impeller of a centrifugal pump may be due to (A) Cavitation (B) Low speed of impeller (C) Its operation with delivery valve closed for considerable time after starting the pump (D) Off centering of pump with motor

Description : Erosion and pits formation on the impeller of a centrifugal pump may be due to (A) Cavitation (B) Low speed of impeller (C) Its operation with delivery valve closed for considerable time after starting the pump (D) Off centering of pump with motor

Last Answer : (A) Cavitation

In centrifugal pump installation, (A) Pump is properly primed before starting (B) The diameter of the pipe at inlet as well as at outlet, is kept smaller than the delivery pipe (C) The motor may burn out if it is started with empty delivery pipe and with open gate valve (D) All the above

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Last Answer : (D) All the above 

Gear pump (A) Is a positive displacement pump (B) Is a centrifugal pump (C) Is a non-positive displacement pump (D) Can be started with delivery valve closed

Description : Gear pump (A) Is a positive displacement pump (B) Is a centrifugal pump (C) Is a non-positive displacement pump (D) Can be started with delivery valve closed

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For the same terminal conditions and valve size, the pressure drop in a fully opened globe valve as compared to that in a gate valve is (A) More (B) Less (C) Equal (D) Either (A) or (B); depends on the viscosity of the fluid

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Reciprocating pumps compared to centrifugal pumps (A) Deliver liquid at uniform pressure (B) Can handle slurries more efficiently (C) Are not subject to air binding (D) Can be operated with delivery valve closed

Description : Reciprocating pumps compared to centrifugal pumps (A) Deliver liquid at uniform pressure (B) Can handle slurries more efficiently (C) Are not subject to air binding (D) Can be operated with delivery valve closed

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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)

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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

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A globe valve is the most suitable for applications, in which (A) Fluid flow control is required (B) Fluid contains dispersed solid particles (C) Valve is required to be either fully open or fully closed (D) One way flow is required

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Last Answer : (A) Fluid flow control is required

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)

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

The vent valve provided in a liquid handling centrifugal pump is (A) Generally a needle valve (B) Used to release any gases that might be vapour locking the pump (C) Helpful in easy removal of samples (D) All (A), (B) and (C)

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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

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

Medium viscosity lubricating oil can be most ideally pumped by a __________ pump. (A) Vane (B) Piston (C) Centrifugal (D) Plunger

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Liquid delivery by centrifugal pump starts, only when the head developed by it is equal to the __________ head. (A) Manometric (B) Total (C) Static (D) Friction

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Last Answer : (D) None of these

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

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)

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

The heart sound ‘dup’ is produced when (a) mitral valve is closed (b) semi-lunar valves at the base of aorta get closed (c) tricuspid valve is opened (d) mitral valve is opened.

Description : The heart sound ‘dup’ is produced when (a) mitral valve is closed (b) semi-lunar valves at the base of aorta get closed (c) tricuspid valve is opened (d) mitral valve is opened.

Last Answer : b) semi-lunar valves at the base of aorta get closed

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

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Theoretical head developed by a centrifugal pump does not depend upon the __________ the impeller. (A) Radius of (B) Speed of (C) Fluid velocity leaving (D) None of these

Description : Theoretical head developed by a centrifugal pump does not depend upon the __________ the impeller. (A) Radius of (B) Speed of (C) Fluid velocity leaving (D) None of these

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In case of a centrifugal pump, the theoretical head developed is dependent on the __________ the impeller. (A) Speed of (B) Diameter of (C) Fluid velocity leaving (D) All (A), (B) and (C)

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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

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

Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump? (A) Increasing the impeller speed and the volute area (B) Increasing the number of vanes in the impeller (C) Mounting of two or more impellers in series on a single shaft (D) Either of (A), (B) or (C)

Description : Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump? (A) Increasing the impeller speed and the volute area (B) Increasing the number of vanes ... or more impellers in series on a single shaft (D) Either of (A), (B) or (C)

Last Answer : (C) Mounting of two or more impellers in series on a single shaft

Which of the following is the most common pump for pumping either raw sewage or sludge? (A) Electromagnetic pump (B) Centrifugal pump (C) Reciprocating pump(D) Gear pump

Description : Which of the following is the most common pump for pumping either raw sewage or sludge? (A) Electromagnetic pump (B) Centrifugal pump (C) Reciprocating pump (D) Gear pump

Last Answer : (C) Reciprocating pump

In a/an __________ vessel, the fluid enters and leaves following plug flow. (A) Open (B) Closed (C) Open-closed (D) Close-opened

Description : In a/an __________ vessel, the fluid enters and leaves following plug flow. (A) Open (B) Closed (C) Open-closed (D) Close-opened

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In case of parallel flow heat exchanger, the lowest temperature theoretically attainable by the hot fluid is __________ the outlet temperature of the cold fluid. (A) Equal to (B) More than (C) Less than (D) Either more or less than (depending upon the fluid)

Description : In case of parallel flow heat exchanger, the lowest temperature theoretically attainable by the hot fluid is __________ the outlet temperature of the cold fluid. (A) Equal to (B) More than (C) Less than (D) Either more or less than (depending upon the fluid)

Last Answer : (A) Equal to

A centrifugal pump is required to be primed before starting if it is located (A) At higher level than water level of reservoir (B) At lower level than water level of reservoir (C) Both (a) and (b) (D) Neither (a) nor (b)

Description : A centrifugal pump is required to be primed before starting if it is located  (A) At higher level than water level of reservoir  (B) At lower level than water level of reservoir  (C) Both (a) and (b)  (D) Neither (a) nor (b) 

Last Answer : (A) At higher level than water level of reservoir

A single-phase induction motor will only start if you spin the rotor rapidly with the line switch closed. After starting, its speed fluctuates between very slow and half-speed. The problem probably lies in the ________. A. starting winding B. centrifugal mechanism C. centrifugal switch D. running winding

Description : A single-phase induction motor will only start if you spin the rotor rapidly with the line switch closed. After starting, its speed fluctuates between very slow and half-speed. The problem ... in the ________. A. starting winding B. centrifugal mechanism C. centrifugal switch D. running winding

Last Answer : Answer: D

A single-phase induction motor fails to start. The rotor is spun rapidly with the line switch closed. Having started by this method it is noted that the motor fluctuates between a very slow speed and half speed. The problem probably lies in the ______ A. starting winding B. centrifugal mechanism C. centrifugal switch D. running winding

Description : A single-phase induction motor fails to start. The rotor is spun rapidly with the line switch closed. Having started by this method it is noted that the motor fluctuates between a very slow ... lies in the ______ A. starting winding B. centrifugal mechanism C. centrifugal switch D. running winding

Last Answer : Answer: D

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

Autotransformer starters or compensators are sometimes used with polyphase induction motors to _____________. A. reduce the voltage applied to the motor during the starting period B. increase the voltage for 'across-the-line starting' C. provide a backup means of voltage regulation for emergency starting D. allow the voltage to be either stepped up or down, depending on the application, to ensure full torque

Description : Autotransformer starters or compensators are sometimes used with polyphase induction motors to _____________. A. reduce the voltage applied to the motor during the starting period B. increase the voltage for ' ... to be either stepped up or down, depending on the application, to ensure full torque

Last Answer : Answer: A

A fluid is a substance, that (A) Has to be kept in a closed container (B) Is almost incompressible (C) Has zero shear stress (D) Flows when even a small shear is applied to it

Description : A fluid is a substance, that (A) Has to be kept in a closed container (B) Is almost incompressible (C) Has zero shear stress (D) Flows when even a small shear is applied to it

Last Answer : (D) Flows when even a small shear is applied to it

Pick out the wrong statement. (A) The form drag is dependent upon the occurrence of a wake (B) The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent) varies linearly as the radial distance (C) An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity (D) Existence of the boundary layer in fluid flow is because of viscosity of the fluid

Description : Pick out the wrong statement. (A) The form drag is dependent upon the occurrence of a wake (B) The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent ... of viscosity (D) Existence of the boundary layer in fluid flow is because of viscosity of the fluid

Last Answer : (C) An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity

Two pumps P & Q can fill a tank in 12 mins and 15 mins respectively while a third pipe R can empty the full tank in 6 mins. P & Q kept open for 5 mins in the beginning and then R is also opened. In what time is tank emptied? A) 30mins B) 35mins C) 40mins D) 45 mins

Description : Two pumps P & Q can fill a tank in 12 mins and 15 mins respectively while a third pipe R can empty the full tank in 6 mins. P & Q kept open for 5 mins in the beginning and then R is also opened. In what time is tank emptied? A) 30mins B) 35mins C) 40mins D) 45 mins

Last Answer : D Part filled in 5 min = 5(1/12 +1/15) = 5*9/60 = ¾ Part emptied in 1 min when all the pumps are opened, = 1/6 – (1/12 + 1/15) = 1/6 – 3/20 = 1/60 Now 1/60 is part emptied in 1 min Therefore ¾ part will be emptied in 60 * ¾ = 45 mins

A bakery P can sold 500 breads in 4 hours, bakery Q can sold the same number of bread in 5 hrs while bakery R can sold them in 6 hrs. All the bakeries are opened at 8 a.m while bakery P is closed at 9 p.m and the remaining 2 bakeries complete their target. Approximately at what time will the work be finished? a) 10 b) 8 c) 12 d) 6

Description : A bakery P can sold 500 breads in 4 hours, bakery Q can sold the same number of bread in 5 hrs while bakery R can sold them in 6 hrs. All the bakeries are opened at 8 a.m while bakery P is closed ... complete their target. Approximately at what time will the work be finished? a) 10 b) 8 c) 12 d) 6

Last Answer : A (P+Q+R)'s 1 hour work = (1/4 +1/5+ 1/6) =(15+12+10)/60 =37/60 Remaining work = 1- 37/60 = 23/60 (Q+R)'s 1 hour work = (1/5 +1/6) =11/30 Now 11/30 work is done by Q and R ... R in(30/11*23/60) =23/22 hrs = 1hr So the work will be finished approximately 1 hr after 9.am i.e., around 10 a.m

In the illustrated ground detection system with a ground on phase A, if the switch is opened __________. EL-0009 A. lamp A will dim or go out depending on the severity of the ground B. all three lamps will return to their normal brightness indicating that the bulbs are not burnt out C. lamps B and C will dim lamp A will be brighter D. lamp A will start flickering if the ground is in an AC induction motor

Description : In the illustrated ground detection system with a ground on phase A, if the switch is opened __________. EL-0009 A. lamp A will dim or go out depending on the severity of the ground B. all three ... lamp A will be brighter D. lamp A will start flickering if the ground is in an AC induction motor

Last Answer : Answer: B

Which of the following parameters of the fluid is not very important, while deciding its route in a shell and tube heat exchanger? (A) Corrosiveness & fouling characteristics (B) Pressure (C) Viscosity (D) Density

Description : Which of the following parameters of the fluid is not very important, while deciding its route in a shell and tube heat exchanger? (A) Corrosiveness & fouling characteristics (B) Pressure (C) Viscosity (D) Density

Last Answer : (D) Density

The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost is P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet. (A) P, Q and R (B) P and R (C) R and S (D) P, Rand S

Description : The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost is P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet. (A) P, Q and R (B) P and R (C) R and S (D) P, Rand S

Last Answer : (A) P, Q and R

What is the difference between an ordinary centrifugal pump and a firefighting pump?

Description : What is the difference between an ordinary centrifugal pump and a firefighting pump?

Last Answer : Generally speaking, the fire pump compared with the ordinary centrifugal pump, the pump body is more reasonable in structure, performance parameter and more applicable, start a ... connection through the national fire products quality supervision and inspection institutions performance testing.

State the difference between Static head & Manometric head in centrifugal pump.

Description : State the difference between Static head & Manometric head in centrifugal pump.

Last Answer : Static head: The sum of suction head & delivery head is known as static head.  Manometric head: It is the total head that pump is required to develop. This include all losses. This is equal to difference between pressure head at inlet & outlet of pump.

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

Head developed by a centrifugal pump depends on its (A) Speed (B) Impeller diameter (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : Head developed by a centrifugal pump depends on its (A) Speed (B) Impeller diameter (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : C) Both (A) and (B)

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

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)

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 power consumed now will be __________ hp. (A) 0.5 (B) 2 (C) 4 (D) 1

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 power consumed now will be __________ hp. (A) 0.5 (B) 2 (C) 4 (D) 1

Last Answer : (A) 0.5

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, then the new head will be __________ metres. (A) 2 (B) 4 (C) 8 (D) 5.5

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, then the new head will be __________ metres. (A) 2 (B) 4 (C) 8 (D) 5.5

Last Answer : (A) 2

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