Pumps PHEP Flashcards
The work of pumping consists of discharging a quantity of liquid or gas against a
Resistance
The motion exerted by pumps on the fluids pumped may be due to
Reciprocating action
centrifugal action
jet action
all of the above
Fluid density, fluid height must be raised, pipe friction, and static pressure all relate to
Total pump head
Check valves are sometimes installed in the suction line of pumps to
Prevent suction loss or shutdown
What type of pump can be operated with the discharge valve closed?
centrifugal
What type of pump operates on the velocity, restriction principle?
ejector
What type of pump is best suited for the handling of dirty water
non-positive displacement
The purpose of the volute type of casing or diffusion vanes of centrifugal pumps is to
reduce the velocity and increase the pressure of the discharging fluid
The laws governing the temperature-pressure relations of the liquids explain why a force must be used to cause a liquid to flow into a pump and relate most nearly to
Net positive suction head
Inter-stage leakage in multi-stage centrifugal pumps is most usually controlled by the use of
Wearing rings
The purpose of wearing or labyrinth rings in centrifugal pumps is to
control inter-stage losses
reduce recircualtion losses
reduce maintenance costs
all three of the above
The function of a lantern ring in the stuffing box of a centrifugal pump is to
distribute sealing or lubricating water around the pump shaft
In what part of a centrifugal pump is the kinetic energy in the fluid converted to potential or pressure energy?
the casing
The head generated by the centrifugal pump is always expressed in
feet of liquid
One foot of pump head is a static force exerted by a column of water one foot high on an area of one square inch. It is equal to how many pounds of pressure?
.434
Which of the following conditions would normally act to increase the total pump head?
Installation of new clearance or wearing rings
Replacing old discharge piping with new piping
Extending the length of discharge piping
Repairing cavitation areas in impellers
Any or all of the above
In a constant speed centrifugal pump, any increase in flow rate beyond that for which the pump is designed to handle will normally cause
A drop in both efficiency and discharge pressure
Specific speed refers to or indicates
the speed a model of a given design would operate to discharge one gallon per minute against one foot head
The most efficient type of impeller to use for conditions of small capacities and high heads would generally be the
radial
Excessive vapors in the inlet or suction side of a liquid pump will cause the pump to
lose prime
