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What is a positive displacement pump?
All water and air are forced out of the pump body with each operating cycle
What was the earliest pump?
Hand operated
What type of pump is used to prime a pump (get the air out)?
positive displacement
What are the two types of positive displacement pumps?
piston rotary
when dealing with piston pumps what is it called when the forward stroke causes water to be discharged, and the return stroke causes the pump to fill with water again?
single action piston pump
When you add additional valves to a piston pump to produce a more constant stream, that also receives and discharges water on each stroke of the piston is called what?
Double action piston pump
For multi cylinder pumps for high pressure stream fire fighting, PTO-driven pumps provide pressure up to how many psi?
up to 1,000 psi
What is a rotary gear pump?
Consists of two gears that rotate in a tightly meshed pattern inside a water tight case
Is a rotary gear pu MP considered a positive displacement pump or centrufugal pump?
A positive displacement pump because each pocket in the gears contains a definite amount of water
To prevent damage to the casings in the rotary gear pumps, what type of metal are they constructed of?
bronze or another soft metal in the gears
What is one of the most common types of pumps to prime a centrifugal pump?
rotary vane pump
What type of pump is constructed with moveable elements that automatically compensated for wear and maintain a tighter fit with closer clearances as the pump is used?
rotary vane pump
Is a centrifugal pump considered a positive displacement pump or no positive displacement pump?
A no positive displacement pump because it doesn\'t pump a definite amount of water with each revolution, rather it gives water velocity and converts it into pressure within the pump itself
how does a centrifugal pump work?
A rapidly revolving disk throws water into the center of the pump and toward the outer edge, the faster the disk is rotating the farther the water is thrown
What are the two parts of the centrifugal pump?
casing impellar
What is an impellar on a centrifugal pump?
It transmits energy in the for of velocity to the water
What does the casing do in a centrifugal pump?
It confines the water in order to convert water from velocity to pressure
How fast does an impellar rotate?
2,000- 4,000 RPM
What is a volute?
the placement of the impelled is placed off center of the pump which creates a a water passage that increases in cross sectional area as it nears the discharge outlet of the pump
What are the three main factors that influence a centrifugal fire pump\'s discharge pressure?
Amount of water being discharged Speed at which the imoellar is turning Pressure of water when it enters the pump from a pressurized source
When there is a large volume of water being discharged, sis the discharge pressure lower or higher?
lower
The greater the speed of the impeller, the the pressure developed
greater
When doubling the speed of the impeller, how much more is the pressure if all other factors remain constant?
four times
What does the centrifugal pump depend on to move water through the pump?
The velocity of water
What are the two types of centrifugal pumps in the fire service?
single stage two stage
what is a single stage centrifugal pump?
A pump that is constructed with only one impeller
Front mount pumps, PTO, seperate engine driven, and mid-ship transfer pump use a single stage centrifugal pump, how many GPM can it provide?
Up to 2,000 GPM
What is a double suction immpeller?
It takes in water from both sides of the pump
What is a multi stage centrifugal pump?
It has an impelled for each stage mounted within a single housing
when pumping in the parallel position ( volume) in a multi-stage centrifugal pump, each impeller is capable of delivering how much of the rated flowing capacity?
50%
Changing the transfer valve from volume to the series ( pressure) position in a multi-stage centrifugal pump, what happens to the pressure and volume?
The pressure increases, while the volume of water decreases
When pumping in the series ( pressure) position in a multi-stage pump, where is all of the water from the intake manifold go?
Into the eye of the impeller
in a single stage pump the first stage increases the pressure and discharge to what percent of the volume capacity through the transfer valve and into the eye of the impeller?
50-70%
The process of switching between pressure and volume is referred sometimes to what?
changeover
According to some SOPs, the transfer valve should be in what position until it is necessary to supply more than one half the rated volume capacity of the pump?
series ( pressure)
When flowing at lower flow rates, in what position reduces the load and required rpm for the engine?
series ( pressure)
Switching from volume to pressure what immediately to the previous discharge pressure?
doubles
What is the maximum discharge pressure for the transfer valve in most cases?
50 psi
If you don\'t know what position to put the transfer valve in what position should you have it in to be on the safe side?
parallel
Many power-operated transfer valves operate at what pressure?
As high as 200 psi
His big is the opening between the pump casing and the hub?
limited to. 01 inch
What should the driver do if a pump intake pipe is warm?
open a discharge or turn on the recirculting valve
What type if material is the packing made of?
rope fibers impregnated with graphite or lead
What happens to the pump if its ran dry for any length of time?
damages the shaft
What is an auxiliary engine driven pump?
A pump that is powered by either gasoline or diesel engine independent of an engine used to drive the vehicle
What are some of the most common applications for auxiliary engine-driven pumps?
ARRF vehicles Wild land fire apparatus Trailor-mounted pumps Portable fire pumps
PTO driven pumps are most commonly found in what type of apparatus?
Initial attack Wild land Mobile water suppy
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