Pumps & Motors Flashcards
The main purpose of mechanical seals is to ________.
a. keep lubrication in and dirt and other foreign materials out.
b. control water leakage from the stuffing box.
c. keep contamination from entering or leaving.
d. save on costs, as they last longer than packing.
b. Control water leakage from the “stuffing box”.
The purpose of packing is to _______.
a. keep oil or graphite on the shaft.
b. control water leakage along the pump’s shaft.
c. prevent water leakage from the pump shaft.
d. help prevent shaft from warping.
b. control water leakage along the pump’s shaft.
Which part of a pump houses the packing or mechanical seal?
a. The shroud
b. The stuffing box
c. The volute
d. The casing head
b. The Stuffing Box.
Which is the only type of pump that can be operated against a closed valve?
a. Vertical turbine pump
b. Centrifugal pump
c. Axial-flow pump
d. Mixed-flow pump
b. Centrifugal pump.
Which device applies an even pressure to the packing such that it compresses tight around the pump shaft?
a. Lantern ring
b. Mechanical seal
c. Packing gland
d. Seal cage
c. Packing gland
When using four packing rings, the rings should be staggered at _______.
a. 45 degrees.
b. 90 degrees.
c. 120 degrees.
d. 180 degrees.
b. 90 degrees
Which type of centrifugal pump impeller is used for pumping medium-sized solids?
a. Open
b. Closed
c. Semi-open
d. Radial
c. Semi-open
The shaft’s main function is to transmit ______ from the motor to the impeller.
a. centrifugal force
b. torque
c. kinetic energy
d. thrust
torque
When external seal water is use as a water source, which should its pressure be in relation to the volute pressure?
a. 3 to 10 psi higher
b. 10 to 15 psi higher
c. 20 to 25 psi higher
d. 25 to 30 psi higher
b. 10 to 15 psi higher.
Under which conditions are regenerative turbine pumps used?
a. High head conditions
b. Low head conditions
c. High volume output
d. Low suction conditions
a. High head conditions.
Approximately, which percentage of flow increase occurs when a two-flight screw pump is changed to a three-flight screw pump, all other things being equal.
a. 10%
b. 20%
c. 33%
d. 40%
b. 20%
The arrangement of pumps in series is primarily used to increase the ________.
a. flow, usually by 70-80%.
b. discharge head.
c. flow, but keep discharge head the same.
d. pump efficiency.
b. discharge head
How much will a flexible disk coupling compensate for in angular movement?
a. 1.0 degree
b. 2.0 degree
c. 3.2 degree
d. 3.7 degree
b. 2.0 degree
The most common solution feeder used for liquid coagulants and coagulant aids is the _______
metering pump
The bearings are protected from water leaking out of the stuffing box by the ______
slinger ring
The purpose of the lantern ring is to ________
distribute lubrication to the packing
Why are roller bearings used?
To reduce friction and heat.
Which type of pump is typically used for dispensing chemical solutions?
diaphragm pump
What disadvantage do peristaltic pumps have?
They require periodic flexible tubing replacement.
Which type of pump is generally used for feeding a fluoride solution because it is accurate and will operate against pressure?
diaphragm pump
In a centrifugal pump, which part physically separates the high pressure zone in the volute from the low pressure zone at the impeller’s eye?
wear rings
When removing the volute case at the gasket from a pump, which tool should be used?
soft-faced hammer
How should a pump’s shaft be stored when not in use?
Pump shaft should be stored vertically, on end.
What should be used to clean an old bearing?
solvent
How often should amperage and voltage tests be performed on three-phase motors?
At least every three months.
When should a mechanical seal be replaced?
When leakage becomes excessive.
Which type of lubrication is best used on pump bearings for light to moderate, high speed, horizontally-shafted pumps
Oil
Which type of centrifugal pump can have water enter from two sides (double suction)
split-case pump
Which type of pump has the ability to rotate its discharge 360 degrees?
end-suction pump
A split-case pump has three impellers. Which type of multistage pump is this?
three-stage
A load, perpendicular to a pump shaft, applied to a bearing is called?
radial load
Which type of coupling is used when the coupled shafts are of two different sizes?
flange coupling
Excessive up-thrust on line shaft turbines is caused by?
Pumping too much water.
Besides providing the enclosure for the impeller, the volute case is also cast and machined to provide a seat for the ________.
impeller rings
Which is a type of rigid coupling?
split coupling
The bearings that maintain the axial positioning of a shaft are called?
thrust bearings
Which type of bearing can operate well against radial loads, but can only withstand very low thrust loads?
Self-aligning double-row ball bearings.
A pump fails to prime because the suction lift is too high. Which is the best solution?
Re-evaluate the pumps requirements and correct the condition.
Which type of pump has little chance of losing its prime, but has the disadvantage of having a lack of access for maintenance or repair?
Submersible pump
Which type of pump adds energy to the fluid flow intermittently?
Positive displacement pump
Diaphragm pumps do not work very well if they have to lift liquids more than about _______.
4 feet
Sleeve bearings that are used in a vertical pump’s column may be lubricated by _______.
an oil drip system
What is the normal temperature for centrifugal pump motor bearings?
1800 F
Which will a flexible diaphragm coupling compensate for in parallel misalignment?
1/8 of an inch
The booster pump used to provide water pressure necessary for a chlorine systems injector to operate properly is usually a __________.
low-head, high-capacity centrifugal-type pump.
The shaft’s main function is to transmit ________ from the motor to the impeller.
Torque
What is the purpose of packing in a pump?
Control water leakage along the pumps shaft.
What is Motor Horsepower?
The horsepower equivalent to the watts of electric power supplied to a motor.
What is brake horsepower?
The power supplied to a pump by a motor.
What is the water horsepower?
The portion of power delivered to a pump that is actually used to lift water.
What is the major cause of bearing failure?
Poor lubrication practices.
Packing replacement is done when _________.
No further tightening can be done on the packing gland.
As water flows through the volute, the pressure head ______ and the velocity head ________.
pressure head increases
velocity head decreases
A bearing is selected according to its _________, ________, and __________.
- load
- speed
- life expectancy
The main purpose of a mechanical seal is to ________.
control water leakage.
The purpose of roller bearings is to _________ and _______.
- Reduce friction
- Support radial and axial loads
New packing rings should be staggered at ________.
90 degrees
Open impellers are usually used to pump water that contains __________.
large solids.
The purpose of the shaft’s sleeves is to protect the shaft from _______, ________, and ________.
- wear
- corrosion
- erosion
The bearings are protected from water leaking out of the stuffing box by the _________.
slinger ring.
What is the only type of pump that can be operated against a closed valve?
Centrifugal pump
Lubrication has the purpose of ________, ________, and _________.
- removing heat and reducing friction
- preventing corrosion
- reducing wear
Which type of impeller is best to use for pumping water with low volume of solids?
Closed impeller.
Most pump packing is composed of ________ with _______ lubrication.
- asbestos base
- with graphite
Pumping energy is measured in ________ head.
- elevation
- pressure
- velocity
