PHEP CH6 Pumps Flashcards
The work of pumping consists of discharging a quantity of liquid or gas against a/an?
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 height fluid must be raised, pipe friction, and static pressure all relate to:
Total pump head
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
Check valves are sometimes installed in the suction line of pumps to:
Prevent suction loss or shutdown
The purpose of volute type of casing or diffusion vanes of centritugal 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 labrynth rings in centrifugal pumps is to
ALL OF THE ABOVE
1.control inter-stage losses
2.Reduce recirculation losses
3. Reduce maintenance cost
The function of a lantern ring in the stuffing box of a centritugal 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 generate 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?
0.434
Which one or the following conditions would normally act to increase the total pump head?
ALL OF THE ABOVE
- Installation of new clearance or wearing rings
2.Replacing old discharge piping with new piping - Extending the length of discharge piping
- Repairing cavitation areas in impellars
In a constant speed centifugal 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 of a model given design would operate to discharge on 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:
Radial
Excessive vapors in the intel or suction side of a liquid pump will cause the pump to:
Lose prime
