CATEGORIES:

# PUMP 6008_Centrifugal Pumps

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Question 1:
In an enclosed, single-inlet impeller:

A - The liquid enters the eye from one side only
B - The liquid passages between the vanes are closed off by the shrouds on both sides
C - A full shroud closes off one side
D - Liquid enters the eye from both sides
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Question 2:
The disadvantages of axial flow pumps include low ________________ capacity and relatively ________ discharge head capability.
A - suction lift, low
B - flow regulation, high
C - suction lift, high
D - flow regulation, low
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Question 3:
Explain why the output volume of a centrifugal pump is variable.
A - because the flow decreases as the head on the pump increases
B - because the pockets of trapped liquid are not evenly dispersed
C - because the flow increases as the head on the pump increases
D - because a centrifugal pump is a positive displacement pump
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Question 4:
The type of impeller pictured is a/an:

A - Open impeller
B - Propeller type
C - Enclosed, single inlet impeller
D - Semi closed, single inlet impeller
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Question 5:
A device used in a centrifugal pump that makes the conversion from velocity energy to pressure energy more effective is the:
A - Volute
B - Diffuser
C - Wear ring
D - Impeller
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Question 6:
The regenerative pump:
A - Has diffuser vanes that can cause a sudden pressure increase at the discharge line which improves efficiency
B - Is typically used in applications requiring high capacity and low pressure
C - Can develop much higher discharge pressures than a centrifugal pump having the same size and speed
D - Does not require a safety valve on the discharge side because of its low discharge pressure
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Question 7:
The regenerative pump, or turbine regenerative pump features an impeller, made up of a number of vanes, which rotates in a volute stationary casing.
A - True
B - False
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Question 8:
Centrifugal pumps are not subdivided into which type:
A - Volute
B - Mixed flow
C - Diffuser
D - Radial flow
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Question 9:
The type of impeller pictured is a/an:

A - Semi closed, single inlet impeller
B - Propeller type
C - Open impeller
D - Enclosed, single inlet impeller
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Question 10:
A centrifugal pump balancing drum:
A - Is installed on the shaft between the first impeller and the balancing chamber
B - Is installed on the shaft between the last impeller and the balancing chamber
C - Is stationary inside the balancing drum head
D - Prevents leakage from the high pressure side of the pump to the low pressure chamber
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Question 11:
Wearing rings for a centrifugal pump can be installed on the:
A - Pump shaft
B - Impeller or casing or both
C - Stuffing box
D - Impeller or shaft or both
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Question 12:
Centrifugal pumps are not subdivided into which type:
A - Mixed flow
B - Volute
C - Diffuser
D - Radial flow
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Question 13:
A centrifugal pump operates by:
A - Imparting velocity energy to the fluid being handled and converting the energy to pressure
B - Imparting pressure energy to the fluid being handled and converting the energy to velocity
C - Trapping a volume of fluid inside a casing and forcing it to the discharge
D - Heating the fluid within the casing to increase pressure
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Question 14:
The regenerative pump, or turbine regenerative pump features an impeller, made up of a number of vanes, which rotates in a volute stationary casing.
A - True
B - False
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Question 15:
The disadvantages of axial flow pumps include:
A - Compact size and the inability to operate at high speeds
B - Low suction lift capacity and relatively low discharge head capability
C - High suction lift capacity and relatively low discharge head capability
D - Large size and the inability to operate at high speeds
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Question 16:
In multistage centrifugal pumps that are equipped with two or more impellers operating in series, the:
A - Double-inlet impeller discharges into a central outlet through a diffuser
B - Discharge of one impeller is connected to the suction of the next impeller
C - Impellers each take suction from opposite ends of the pump
D - Fluid is trapped, pressurized, and then released to the discharge
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Question 17:
Pump wear rings are installed on an impeller by set screws, threading or:
A - Soldering
B - Welding
C - Shrinking
D - Brazing
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Question 18:
Pumps that develop head partly by centrifugal force and partly by creating lift with propeller-like impellers are referred to as:
A - Axial flow pumps
B - Barrel pumps
C - Mixed flow pumps
D - Vertical volute pumps
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Question 19:

You have been tasked with designing a centrifugal pump. The pump will need to move fluids but occasionally solids will be mixed into the liquid. Which type of impeller would you recommend? Select the letter under the appropriate impeller.

A - A
B - C
C - E
D - F
E - G
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Question 20:
Theoretically, on multistage pumps that have all the single-inlet impellers facing in one direction, the axial thrust toward the suction end of the pump will be:
A - equal to the sum of the individual impeller thrusts
B - greater than the sum of the individual impeller thrusts
C - less than the sum of the individual impeller thrusts
D - independent of the individual impeller thrusts
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Question 21:
Wearing rings are often made of:
A - Bronze or cast iron
B - Steel or alloy steel
C - Aluminum or brass
D - Wrought iron or bronze
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Question 22:
For multistage volute or diffuser pumps with discharge pressures above 10,000 kPa:
A - Barrel casings are used to avoid the difficulty of maintaining a tight seal between the halves of a casing
B - Radially split casings are used to avoid the difficulty of maintaining a tight seal between the sections of a casing
C - Horizontally split casings are used to avoid the difficulty of maintaining a tight seal between the halves of a casing
D - Balancing drums are used to avoid the difficulty of maintaining a tight seal between the halves of a casing
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Question 23:
In a volute centrifugal pump, as the liquid travels through the volute casing to the discharge:
A - It is trapped, pressurized, and then released to the discharge
B - Its velocity energy is converted into pressure energy
C - It is heated to produce pressure energy
D - Its pressure energy is converted into velocity energy
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Question 24:
A regenerative pump can develop _____________________ than a centrifugal pump of the same size and speed.
A - faster flow rates
B - considerably lower suction pressures
C - much higher discharge pressures
D - much lower discharge pressures
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Question 25:

On low capacity, single-stage pumps, axial movement of the impeller is usually prevented by:
A - Using a double-inlet impeller
B - A thrust bearing on the shaft
C - Using opposed impellers
D - A wearing ring on the backside of the impeller

PUMP 6014_Pumps, Seals and bearings

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Question 1:
All of the following are causes of mechanical seal failures in pumps except:
A - No air in seal housings at start-up
B - Distorted rings
C - Cut gaskets
D - Misaligned piping
E - Scored or grooved seal faces
F - Excessive pump shaft vibration
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Question 2:
The mechanical seal configuration in which seals are mounted with one facing the suction end and one facing the discharge outlet is called:
A - Back to back
B - Concentric
C - Face to face
D - Tandem
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Question 3:
A mechanical seal, known as a "pusher" type:
A - Uses a bellows to provide the necessary spring loading for seal face contact
B - Uses a dynamic secondary seal or o-ring that seals the fluid path
C - Does not use a dynamic secondary seal or o-ring
D - Has a single spring coil fits over the shaft and bellows
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Question 4:
The type of bearing used in pumps in the illustration is called a:

A - Needle roller bearing
B - Tapered roller bearing
C - Cylinder roller bearing
D - Spherical roller bearing
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Question 5:
The gland that holds the packing inside the stuffing box must not be tightened too much, because:
A - The shaft sleeve will not be able to rotate, causing excess friction
B - A negative suction pressure is needed along the shaft to lubricate and cool the packing
C - The shaft must be allowed to create friction against the packing for pressure
D - A small amount of leakage is needed along the shaft to lubricate and cool the packing
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Question 6:
The mating ring of a mechanical seal:
A - Is positioned so that it has no contact with the sealing ring
B - Holds the stuffing box packing in place
C - Is held in position by a spring
D - Is positioned with its face in contact with that of the sealing ring
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Question 7:
The component of a rotating mechanical seal that is held stationary in a recessed part of the pump housing, or the seal housing cover, is referred to as:
A - The shell
B - The O-ring
C - The mating ring
D - The sealing ring
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Question 8:
Care must be taken when tightening the gland that holds the packing in place because a small amount of _____________ is needed along the _____________ to lubricate and cool the packing.
A - leakage, shaft
B - air, lantern ring
C - seal, bushing
D - sealing liquid, stuffing box
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Question 9:
The shell of a rotating mechanical seal is secured to the shaft by setscrews and holds the ______________ so that it turns with the shaft.
A - Mating ring
B - Sealing ring
C - Seal cage
D - Gland
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Question 10:
The term "dynamic pump seal" means that:
A - The shaft must be able to move freely while the seal prevents fluid loss
B - Slight leakage must be allowed to confirm that the seal is functioning correctly
C - It must be possible to tighten any seal leaks without shutting the pump down
D - The shaft and seal must be able to turn together
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Question 11:
Sleeve and shell bearings are usually:
A - Oil lubricated
B - Air-cooled
C - Water-cooled
D - Packed with grease
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Question 12:
The type of bearing used in pumps in the illustration is called a:

A - Needle roller bearing
B - Cylinder roller bearing
C - Deep groove ball bearing
D - Spherical roller bearing
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Question 13:
A lantern ring is normally installed on a pump when the:
A - Fluid being handled is gasoline, acid, or ammonia
B - Fluid is clean, but the suction pressure is always positive
C - Pump must handle fluids containing abrasive solids
D - Mechanical seal is stationary and requires a cooling water supply
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Question 14:
What should a pump that operates with negative suction pressure be equipped with to prevent air being drawn into the casing?
A - lantern rings and sealing water connections
B - packing rings and a pump shaft
C - shaft sleeves and sleeve adjustment nuts
D - stuffing boxes and auto-lubricators
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Question 15:
Packing in the stuffing box of a pump:
A - Will not wear the pump shaft
B - Should stop leakage entirely
C - Requires no lubrication
D - Should not stop leakage entirely
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Question 16:
The mechanical seal configuration where the sliding faces of two spring backed seals run against a common stationary seat is called:
A - Back to back
B - Tandem
C - Concentric
D - Face to face
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Question 17:
Mechanical seals:

A - Cannot be designed to work under very high temperatures and pressures
B - Reduce leakage to a minimum
C - Cause wear on shafts or shaft sleeves
D - Require more maintenance than packing rings
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Question 18:
The sealing ring of a stationary mechanical seal:
A - Rotates with the shaft
B - Serves to distribute sealing liquid
C - Is held stationary
D - Does not require an O-ring

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Question 19:
Needle roller bearings are very popular in the petroleum industry because their axial load-handling capacity is very high.
A - True
B - False
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Question 20:
If smoke is coming from the stuffing box of a pump, the most likely cause is:
A - The pump shaft is beginning to deteriorate
B - The liquid in the pump is too hot and the pump is vapour locked
C - The wrong packing has been installed in the gland
D - The gland is over-tightened
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Question 21:
In a rotating mechanical seal:
A - A raised shoulder on the shaft accommodates the mating ring
B - A shell secured to the shaft by setscrews holds the mating ring so that it turns with the shaft
C - A shell secured to the shaft by setscrews holds the sealing ring so that it turns with the shaft
D - There is no need for O-rings because the mating surfaces provide the seal

Date: 2015-12-17; view: 1847

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