Pump 10 Flashcards
The modern fire department is equipped with a ($$$$$) as its main pump.
Centrifugal pump
The ($$$$$$) does not use positive action to force water through the pump, it depends of the velocity of the water produced by the centrifugal force to provide the necessary pump discharge pressure for effective operation.
Centrifugal pump
The forward stroke causes waster to be discharged, and the return stroke causes the pump to fill with water again. This is known as a ($$$$$$). Adding two additional valves can produce a more constant stream. This is known as a ($$$$$$) because it both receives and discharges water on each stroke of the piston.
Single acting piston pump
Double a ting piston pump.
Although piston pumps are no longer used as high capacity pumps, some are still in service for high pressure stream fire fighting. These multi cylinder , PTO driven pumps provide pressures up to ($$$$$)
1000 psi
($$$$$) pumps are the simplest of all fire apparatus pumps from a stand point of design.
Rotary type
The ($$$$$) consists of two gears that rotate in a tightly meshed pattern inside a water tight case.
Rotary gear pump.
The ($$$$$) is constructed with movable elements that automatically compensate for wear and maintain a tighter fit with close cleanser cues as the pump is used.
Rotary vane pumps
In this type of pump the rotor is mounted off center inside the housing. The distance between the rotor and the housing is much greater. At the intake than it is at the discharge.
Rotary vane pumps
The ($$$$$) is classified as a non positive displacement pump because it does not pump a definite amount of water with each revolution.
Centrifugal pump
Fundamentally the centrifugal pump consists of two parts: an ($$$$) and a ($$$$$)
Impeller
Casing
The ($$$$) transmits energy in the form of velocity.
Impeller
He ($$$$) collects the water and confines it in order to convert the velocity into pressure.
Casing
The impeller rotate very rapidly, generally from ($$$$$$).
2000 to 4000 rpm
The impeller is mounted off center in the casing. This placement creates a water passage that gradually increases in cross sectional area as it nears the discharge outlet of the pump. This section of the pump is known as the ($$$$$)
Volute
The greater the speed of the impeller the greater the ($$$$) developed.
Pressure
Ther are two basic types or centrifugal pumps used by the fire service
Single stage and
Two stage
Front mount pumps, power take offs separate engine driven, and mid ship transfer pumps use a single impeller and a simple casing to pro vide capacities up to ($$$$$).
2000 gpm
To minimize the lateral thrust of large quantities of water entering the eye of the impeller a ($$$$$$$) was designed.
Double suction impeller
The ($$$$$$) takes in water from both sides; the reaction being equal and positive cancels the lateral thrust.
Double suction impeller
The ($$$$) has an impeller for each stage mounted within a single housing.
Multi stage centrifugal pump
If a two stage pump is rated at 1000 gpm at 150 psi each of the impellers supplies ($$$$$) to the pump discharge manifold. There the two stream combine, so the total is 1000 gpm at a net pump pressure of 150 psi
500 gpm
Changing the pump discharge pressure to the ($$$$), position greatly increases the maximum pressure attainable. However increasing pressure results in a corresponding decrease in volume.
Series or pressure
When the transfer valve is in the ($$$$)position, all the water from the intake manifold is directed into the eye of the first impeller.
Pressure