Practice Problems in Pumps
1.
A single-acting air pump has an effective swept stroke
volume of 0.08 m3 and the total volume of the vessel and
pipeline to which it is connected is 14 m3. Commencing
with a pressure of 101.3 kPa in the line, find the number
of suction strokes required to reduce the pressure to 35
kPa assuming the temperature remains constant
throughout.
a. 507
b. 61
c. 175
d. 187
2. A fuel pump is delivering 18 gallons per minute of oil
with a specific gravity of 0.80. The total head is 75
meters. If the power input to the pump is 1.1 hp,
what is the efficiency of the pump?
a. 69.3%
b. 75%
c. 72.1%
d. 81.4%
3. Water is to be raised to a height of 30 meters at a
rate of 10 kg/s. Heat loss due to friction is 2 kw. Inlet
and exit pipe diameters are 2 inches and 3 inches
respectively. Determine the motor power required
to drive this pump.
a. 2.943 kw
b. 4.943 kw
c. 3.943 kw
d. 5.943 kw
4. A pump Is lifting water through 5.486 m to fill a
566.254 m3 tank. The overall energy efficiency is
80%. Calculate the length of time that 7.46 kW
applied to the pump will require to complete the job.
a. 85.11 min
b. 81.51 min
c. 75.11 min
d. 71.51 min
5. A plant has installed a single-suction centrifugal pump
with a capacity of 300 gpm under 200 ft at 1200 rpm. It
is proposed to install another pump with double
suction but of the same type to operate at 100 ft head
and delivers 400 gpm. Determine the speed of the
proposed pump.
a. 800 rpm
b. 875 rpm
c. 850 rpm
d. 910 rpm
6. A boiler feedpump receives 300 liters of water at 90 C
(h = 839.33 kJ/kg) per minute. It is operating against a
total head of 800 m. Calculate for the enthalpy of the
fluid leaving the pump, in kJ/kg. Assume a pump
efficiency of 70 percent.
a. 870.2
b. 860.3
c. 857.2
d. 847.2
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