144 Questions
What is the primary function of a pump in industrial plants?
To add energy to the liquid
What is the typical power requirement of a lubricating oil pump?
A fraction of a kW
Which type of pump is used to supply water to plant fire suppression systems?
Fire pump
What is the primary function of a boiler feedwater pump?
To supply feedwater to the boiler
What is the range of temperatures that pumps can handle?
Very high temperatures to extremely low temperatures
What type of pump is used to pump water through heat exchangers?
Circulating water pump
What is the primary purpose of anchoring a pump to a firm location?
To control vibration and ensure stability
What is the force exerted by one liter of pure water at 4°C on a unit area of one square meter?
9.81 N
What is the relationship between pressure, density, acceleration due to gravity, and height of liquid?
p = ρgh
What is the effect of the shape of the piping system on the pressure at its base?
It has no effect on the pressure
What is the purpose of translating pressures into equivalent head in meters in pumping theory?
To simplify the design of pumping systems
What is the density of mercury compared to water?
13.6 times
What is the effect of the density of the liquid being pumped on the pressure developed by a pump?
It increases the pressure
What is the primary consideration for locating pumps?
Accessibility for monitoring and maintenance
What is the pressure exerted by a liter of water at the base of a container with an area of 0.0049 m²?
2002 Pa
What is the phenomenon described in Figure 1?
Pascal's Paradox
What is the definition of static head in a pumping system?
The head measured with the pump off and no liquid flowing
What is the static discharge head?
The distance above the centre line of the pump and the liquid level of an elevated discharge tank
What is the static suction lift?
The distance between the surface of the liquid level of a supply tank and the centre line of the pump
What is the maximum suction lift of a pump at sea level?
10.34 m
Why should centrifugal pumps be placed close to, or preferably below, the water supply?
Because they have a lower suction lift than piston or plunger pumps
What is the pressure head?
The pressure required to overcome the vessel pressure when discharging into a pressurized vessel
What is the total static head?
The vertical distance between the surface liquid line of the supply tank to the surface of the liquid line in the discharge tank
What is the dynamic head?
The pressure required to develop and maintain fluid velocity
Why does the atmospheric pressure vary with altitude?
Because of the change in air density with altitude
What is the reason for the pump to lift water when it draws from a supply tank located below its centre line?
Because of the downward pressure of the atmosphere on the surface of the water
What is the primary source of resistance in pipes, valves, and fittings?
Friction head
What is the relationship between friction head and fluid flow rates?
Friction head increases as fluid flow rates increase
What is the purpose of Net Positive Suction Head (NPSH)?
To ensure the pump does not cavitate or become vapour-bound
What is the characteristic of a positive displacement pump?
It moves liquid by creating a void
What is the main difference between reciprocating and rotary pumps?
The movement of the plungers or pistons
What is the purpose of the suction valves in a reciprocating pump?
To draw the liquid into the cylinder
What is the formula to convert kinetic energy to potential energy?
v^2 = 2gh
What is the total dynamic head composed of?
Total static head and dynamic head
What is the purpose of the discharge valves in a reciprocating pump?
To force the liquid out of the cylinder
What is the type of pump that moves liquid by creating a pressure differential?
Dynamic pump
What is the primary reason why fluid is expelled from the gear pockets in gear pumps?
The fluid and the tooth cannot be in the gear pocket at the same time
What is a main difference between gear pumps and rotary lobe pumps?
The synchronization of the lobes
In a sliding vane pump, what causes the size of the pockets to decrease?
The diminishing clearance to the pump casing
Why is a pressure relief device necessary in a positive displacement pump?
To prevent excessive pressure buildup
What is the primary advantage of peristaltic pumps in feedwater treatment and chemical dosing systems?
No contact between the fluid and pump parts
In a progressive cavity pump, what is the function of the liquid being pumped?
It lubricates the rotor and stator
What is a characteristic of progressive cavity pumps?
They have a constant flow with little or no pressure pulsation
What is the primary mechanism of dynamic pumps?
The continuous addition of energy to the fluid
In a centrifugal pump, what is the primary function of the impeller?
To impart energy to the fluid in the form of velocity
What is a common application of progressive cavity pumps?
Pumping industrial sewage
What happens when the pressure inside a centrifugal pump drops below the vapour pressure of the liquid?
The liquid vaporizes and forms bubbles
Why is it important to avoid power surges in buildings with large electric lighting loads?
To prevent disturbance to the lighting and other equipment
What happens when a centrifugal pump is started with a closed discharge valve?
The pump's power requirement is reduced
What is the main characteristic of a regenerative pump?
It can develop pressures several times that of a centrifugal pump of similar size and speed
What is the main consequence of cavitation in a centrifugal pump?
Mechanical destruction of the pump
Where does cavitation typically occur in a centrifugal pump?
On the suction side of the pump or in the inlet portion of the impeller
What is the main consideration when selecting materials for a diaphragm?
Corrosion resistance
What is the difference between a single-acting and a double-acting pump?
Number of strokes per cycle
What is the purpose of the suction ball check in Figure 5?
To draw the liquid into the cylinder
What is the advantage of a double-acting pump over a single-acting pump?
More fluid is pumped per cycle
What type of pump is shown in Figure 7?
Diaphragm pump
What is the characteristic of diaphragm pumps that makes them suitable for pumping corrosive fluids?
Flexible diaphragm material
How do rotary pumps achieve high pressure without pulsations?
By trapping pockets of fluid
What is the function of the gears in a rotary gear pump?
To convey pockets of fluid to the discharge side
What is the advantage of using a diaphragm pump for pumping chemicals?
They can pump low volumes at high head
What is the purpose of the valves in a positive displacement pump?
To allow the fluid to flow in one direction only
What is the primary purpose of the volute casing in a radial flow centrifugal pump?
To convert the velocity of the liquid into pressure
What is the result of throttling the discharge valve on a centrifugal pump?
The flow rate decreases and the pressure increases
What is the characteristic of a centrifugal pump that differentiates it from a positive displacement pump?
The capacity of the pump changes with the change in head
What is the purpose of the stationary diffuser vanes in a diffuser centrifugal pump?
To convert the velocity of the liquid into pressure
What is the common application of axial flow pumps?
Low-head, high-flow applications
What is the result of running a centrifugal pump with its discharge valve shut for extended periods of time?
The pump will experience cavitation and damage
What is the direction of the liquid flow in a radial flow centrifugal pump?
Perpendicular to the pump shaft
What is the purpose of the impeller in a centrifugal pump?
To convert the velocity of the liquid into pressure
What is the characteristic of a mixed flow pump?
It moves the liquid flow diagonally to the pump shaft
What is the effect of shutting the suction valve on a centrifugal pump?
It will cause destructive cavitation and damage to the pump
What is the primary function of a circulating water pump in an industrial plant?
To continuously move liquid in systems such as building heating systems
What is the range of power requirements for pumps in industrial plants?
From a fraction of a kW to nearly 75 000 kW
What type of pump is used to supply feedwater to the boiler in an industrial plant?
Boiler feedwater pump
What is the primary function of a fire pump in an industrial plant?
To supply water to plant fire suppression systems
What type of pump is used to supply fuel to oil burners in an industrial plant?
Fuel oil pump
What is the characteristic of pumps used in industrial plants that allows them to handle extreme temperatures?
They are designed to handle a wide range of temperatures
What is the primary factor that affects the pressure exerted by a column of liquid on the base of a container?
The density of the liquid
What is the relationship between the pressure and height of a liquid in a container?
Pressure is directly proportional to the height of the liquid
What is the purpose of anchoring a pump to a firm location?
To increase stability
What is the advantage of using head instead of pressure in pumping theory?
It is independent of the density of the liquid
What is the consequence of ignoring the density of the liquid being pumped?
The pump will produce less pressure
What is the significance of Pascal's Paradox in pumping theory?
It shows that pressure is independent of the shape of the container
What is the purpose of using reinforced concrete foundations for large pumps?
To provide stability and control vibration
What is the relationship between the force of gravity and the weight of a liquid?
The force of gravity is proportional to the weight of the liquid
What is the advantage of using a small pump instead of a large pump?
It is less expensive
What is the consequence of placing a pump at the bottom of a lake or well?
The pump will produce more pressure
What is the primary effect of increasing fluid flow rates on friction head?
Friction head increases
Which type of pump converts kinetic energy to potential energy?
Dynamic pump
What is the purpose of calculating Net Positive Suction HeadAvailable (NPSHA)?
To ensure the pump does not cavitate or become vapour-bound
What is the characteristic of a positive displacement pump that makes it suitable for pumping liquids at a constant flow rate?
It moves a specific amount of liquid regardless of pump head
What is the primary component of a reciprocating pump that creates a void to move liquid?
All of the above
What is the result of a pump running with its discharge valve shut for an extended period of time?
The pump will develop shut-off head
What is the primary purpose of the static head in a pumping system?
To take into account the lift or elevation of the pump
Which type of pump is suitable for pumping corrosive fluids due to its characteristic?
Diaphragm pump
What is the effect of increasing the velocity of a fluid on its kinetic energy?
The kinetic energy increases
What is the formula to convert kinetic energy to potential energy in a pumping system?
mv^2 = mgh
What is the primary advantage of using a diaphragm pump for pumping corrosive liquids?
The diaphragm does not come into contact with the fluid being pumped
What is the primary reason why a pump is able to lift water from a supply tank located below its centre line?
Because of the pressure exerted by the atmosphere on the surface of the water
What is the main difference between a single-acting and a double-acting pump?
The number of strokes required to move fluid
At what altitude is the atmospheric pressure equivalent to approximately 9.1 m of water head?
1100 m
What is the purpose of the suction valves in a reciprocating pump?
To allow the liquid to flow into the pump
Which type of pump has a poorer suction lift than piston or plunger pumps?
Centrifugal pump
What is the characteristic of a rotary pump that allows it to deliver high pressure liquid without pulsations?
The transfer of pockets of liquid from the low-pressure side to the high-pressure side
What is the term for the pressure required to overcome the pressure of a vessel, such as a boiler or deaerator, when a pump discharges water into it?
Pressure head
What is the advantage of using a gear pump over a reciprocating pump?
It is less prone to pulsations and vibrations
What is the total height that the liquid is moved by the pump, including the pressure head, if pumping into a pressurized vessel?
Total static head
What is the purpose of the discharge valves in a reciprocating pump?
To force the liquid out of the pump
Why is it important to avoid locating pumps too far above the water supply?
Because of the limited suction lift of the pump
What is the term for the distance between the centerline of the pump and the surface of the liquid level in an elevated supply tank?
Static suction head
What is the main difference between a simplex and a multiplex pump?
The number of stages in the pump
What is the primary consideration when selecting materials for a diaphragm?
The reactivity of the material with the fluid being pumped
What is the primary reason why the maximum suction lift of a pump cannot be attained in reality?
All of the above
What is the term for the distance above the centre line of the pump and the liquid level of an elevated discharge tank?
Static discharge head
What is the function of the gears in a rotary gear pump?
To convey pockets of liquid to the discharge side of the pump
What is the primary reason why the atmospheric pressure varies with altitude?
Because of the height above sea level
What is the main advantage of using a rotary pump over a reciprocating pump?
It is less prone to pulsations and vibrations
What is the primary mechanism by which rotary lobe pumps transfer fluid?
By rotating lobes that mesh to expel fluid from the pockets
What is the main advantage of progressive cavity pumps in pumping slurries and abrasive liquids?
The elastomer-lined stator reduces wear and tear on the pump
What is the primary reason to start large centrifugal pumps with a closed discharge valve?
To reduce the pump's power requirement during startup
What is the primary function of the stationary diffuser vanes in a diffuser centrifugal pump?
To convert the velocity of the liquid into pressure
In a centrifugal pump, what is the effect of the collapse of bubbles on the impeller surface?
The metal surface is worn away
What is the characteristic of a regenerative pump that differentiates it from a centrifugal pump?
It can develop higher pressures
Why is it necessary to install a pressure relief device in the discharge line of a positive displacement pump?
To prevent excessive pressure buildup in the pump
What is the primary characteristic of a dynamic pump?
They add energy continuously to the fluid
Why is it important to avoid power surges in buildings with large electric lighting loads?
To prevent severe dimming of lights and equipment shutdown
What is the primary function of the rotor in a progressive cavity pump?
To form tightly sealed cavities with the elastomer-lined stator
What is the primary consequence of operating a regenerative pump with the discharge valve fully closed?
The pump will be damaged
What is the main difference between gear pumps and rotary lobe pumps?
The external gears that drive the rotation of the lobes
What is the effect of throttling the flow in a centrifugal pump on its power requirement?
It will decrease the power requirement
What is the primary advantage of peristaltic pumps in feedwater treatment and chemical dosing systems?
The fluid and the pump parts do not make contact
What is the primary function of the sliding vanes in a sliding vane pump?
To conform to the changing proximity of the pump casing
What is the primary mechanism by which dynamic pumps add energy to the fluid?
By rotating the impeller and increasing the velocity of the liquid
What is the primary reason for the conversion of velocity energy to pressure energy in a centrifugal pump?
To comply with the law of conservation of energy
What is the function of the stationary diffuser vanes in a diffuser centrifugal pump?
To make the conversion from velocity to pressure more effective
What is the direction of the liquid flow in an axial flow pump?
Axial to the pump shaft
What happens when the discharge head of a centrifugal pump increases?
The capacity of the pump decreases
What is the effect of throttling the discharge valve on a centrifugal pump?
The flow rate decreases
What is the purpose of the volute casing in a radial flow centrifugal pump?
To convert the velocity energy to pressure energy
What is the characteristic of a centrifugal pump that differentiates it from a positive displacement pump?
The pump's ability to change its capacity with the change in head
What is the result of running a centrifugal pump with its suction valve shut for an extended period of time?
Cavitation occurs
What is the common application of mixed flow pumps?
Low head, high flow applications
What is the effect of adjusting the discharge valve on a centrifugal pump?
The flow rate decreases
This quiz covers the various uses of pumps in industrial settings, including the movement of fluids at extreme temperatures and pressures. It also explores the range of capacities and power requirements of pumps. Test your knowledge of pump applications in industrial plants!
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