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.