Introduction To Pumps Flashcards
Positive displacement pumps cannot handle entrained air
False
All positive displacement pumps have pumping chambers
True
Double-acting piston pumps discharge an equal amount of liquids on all strokes
False
Which one of the following reciprocating pumps can be allowed to run dry
Diaphragm pump
Rotary pumps produce a smoother flow than reciprocating pumps
True
Which of the following pumps is not dynamic
Reciprocating
What is the definition of absolute pressure
Gauge pressure plus atmospheric pressure
What is the equivalent head of oil when a pressure gauge reads 100 psi (the oil density is 56lb/ft3
257
As pressure is reduced, the boiling point of a liquid decreases?
True
What occurs in a pump when a liquid vaporizes in a closed system
Cavitation occurs
A tank 20’ high is full of brine,the RD of brine is 1.03. What would the reading be on a pressure gauge connected to a pipe leading from the bottom of the tank
8.9 psig
What could cause cavitation to occur
An increase in liquid velocity
In a closed system, as the velocity energy increases,
The pressure energy decreases?
True
When the pump inlet is above the level of liquid in the supply reservoir, the pump has a suction head?
False
What source of energy is available to allow liquid to enter a pump with suction lift
Atmospheric pressure
Which pump component converts mechanical energy to kinetic energy?
Impeller
What value must the NPSHa be for proper pump operation
Less than the NPSHa
Diffusers :
Are stationary
Unless otherwise stated, pump performance curves are based on handling of what type of fluid
Cold water
Pump curves are provided by the pump manufacturer
True
What does not contribute to friction loss through pipes
Increase in atmospheric pressure
What could be a possible cause for an increase in differential pressure across a strainer
The strainer needs to be cleaned
When you have a safe work permit to service a pump,what is the first thing you must do before commencing work
Isolate the pump’s prime mover (tagged and locked out )
