Chapter 73- Types Of Pumps Flashcards
Pumps handling cryogenic materials operate at
Extremely low tempuratures
A pump capable of producing water pressure above the boiler pressure in order to add water in the boiler is the__________ pump.
Feedwater pump
A pump which supplies oil to the burner is the _______ pump
Fuel oil pump
Friction Head
When the pump puts the water in motion, this water will meet resistance in the pipes, valves and fittings. To over come this resistance a certain amount of pressure, called the friction head and expressed in meters of water, is required.
Velocity Head or equivalent head.
Velocity head is the force required to move the water at a specific velocity
Pressure head
When the pump discharges the water into a vessel under pressure, such as a boiler, it must impart additional pressure, called the pressure head, to the water to overcome the pressure
Dynamic head
Friction+ velocity+ pressure head = dynamic head
Total head
The total head required to move the water from the source of supply to the point of discharge is the sum of the static and dynamic head
The power required to drive a pump is determined by the amount of liquid pumped and the total head against which the pump operates.
Static discharge head
The vertical distance, in feet, from the center line of the pump to the free surface of the water in the discharge tank is called the discharge head.
Total static head
The vertical distance from the surface of the source of the supply to the surface of the water in the discharge tank.
The total height a pumps lifts the water
Static suction head
The distance from the free surface of the supply tank to the Center line of the pump
A pump which supplies water to the cooling tower is the _________ pump.
Circulating water
A pump is capable of suction lift due to:
Atmospheric pressure
A pump that supplies water to the cooling tower is called
The circulating water pump
The total static head of the pump is the
The difference between the static suction head and the static discharge head
Centrifugal pumps do not develop good suction lift because
There internal component clearances are to high
The vertical distance from the liquid surface up to the pumps Center-line plus the vertical distance from the pump Center-line up to the surface of the liquid in the discharge tank.
total static head
The difference between static suction head and static discharge head
Total Static head
Preferably, dynamic pumps should be located
Below the liquid source when suction head is involved
A hot water heating system circulator should be
Very quiet in operation
The capacity of a centrifugal pump
Varies with discharge pressure
Centrifugal pumps power requirements are decreased when
The litres moved per minute is decreased
A rotary pump should be equipped with a
Relief valve
A rotary pump is
A high pressure positive displacement pump
A diffuser pump is
Has a high efficiency (more then volute) and a high suction
Cavitation refers to
The pump is being filled with vapor
A circulating pump is usually connected to
Some type if heat exchanger
A multi stage boiler would be use for
When the head is great
Betcha it is ;)
Turbine pumps are used for
Low capacity high pressure services
Reciprocating pump is defined by
In reciprocating pumps the pumping action is produced by the back and forth motion of the piston or plunger within a cylinder
Centrifugal pumps are defined as
A centrifugal pump uses centrifugal force to develop velocity in the liquid being handled. The velocity is then converted to pressure when the liquid velocity decreases.
Is a centrifugal pump considered a positive displacement pump
No
When the head increases in a centrifugal pump what happens
The capacity drops, if the head increases too much then the capacity drops to zero
In a centrifugal pump the suction valve
Must always be open
If the discharge valve on a centrifugal pump is closed
The pump may over heat
Define cavitation
When pressure drops the liquid may become a vapour, when this vapour goes to a higher pressure area these bubbles collapse cause a shock wave potentially damaging equipment
A pump is…..
A mechanism used to move liquids by adding energy to the liquid being moved.
Boiler feed water pumps must be capable to?
Force the water over the pressure existing in the boiler.
What is used to support large pumps?
Reinforced concrete foundations. For stability and vibration control.
Small pumps may be operated by which ones?
a) hand/foot
b) air pressure
c) another fluid pressure
d) electromagnet
A,B,C,D (All of the above)
Pumps are classified into three groups?
Reciprocating, Rotary, Centrifugal
What is double-acting mean?
When both sides of the piston are take part in the pumping action; liquid is discharged when the piston moves in either direction.
A centrifugal pump uses what kind of force?
Centrifugal force
