9 Fire Pump Theory Flashcards
Positive displacement pump using one or more reciprocating Pistons to force water from the pump chamber
Piston pump
Type of pump commonly used for primer pumps
Rotary gear pump
Pump with one or more impellers that rotate and utilize forced to move the water modern fire pumps are of this type
Centrifugal pump
Three main factors that influence a centrical fire pump discharge pressure
Amount of water being discharged.
Speed at which impeller is turning.
Pressure of water when it enters the pump
Centrifugal pump is unable to pump air and is therefore not
Self priming
Two-stage pump or multistage pump operates in volume position when they are pumping in what
Parallel
Multistage pump operates in the pressure position when it is pumping in what
Series
If there’s any question as to the correct position for the transfer valve and a multistage pump the best is to operate in what mode
In parallel, volume mode
What is the essential part for the operation of a multistage pump
Clapper or check valve
Multistage pumps with the ability for pumping high pressures are especially useful for what application
Pumping tall high-rise standpipe or sprinklers
True false positive displacement pump potential damage can result from shutting off discharges
True
What happens in a centrifugal pump when the discharges are closed
The water is heated and it builds up
To prevent water temperature from building up in a centrifugal pump operator do
Open the tank fill valve to circulate water
True false generally when the pump is operating under pressure water should trip at a rate specified by the manufacture from the packing but not run as a steady stream
True
What happens if the pump is not used for an extended period of time
The packing may dry out and cause excessive leaking
Centrifugal pumps rely on what force of action to provide the pressure needed to achieve proper water discharge pressure
Velocity of the water produced by centrical force
Pumps powered by gasoline or diesel engines independent of the vehicle drive engine are examples of
Auxiliary pumps
Auxiliary palms generally have the capacity to pump what volume
500 GPM or less
Mechanism that allows a vehicle engine to power equipment such as a pump it is typically attached to the transmission
Power take off. PTO
Front mount pumps typically have a pumping capacity of up to
1250 gpm
Fire pump mounted in front of the vehicle and powered off the crankshaft
Front mount pump
In order to determine if the pump is engaged and operator can check what gauge in the cab
Speedometer, between 10 to 15 mph
Type of power system that runs off of the driveshaft to a transfer case using chains or belts to operate the pump
Split shaft system
Piping of the pump system must be capable of withstanding hydrostatic test of how many PSI
500 psi before being placed in the service
Pumpers with a capacity of 500 GPM or less should have piping capable of flowing how many GPM
250 gpm
Conference with the capacity of 500 GPM or more should be able to flow how much through it’s piping
At least 500 gpm
Pumps with a capacity of greater than 750 gallons per minute must be equipped with how many two and half inch discharges
At least two
Pump rated less than 750 GPM are required to have how many 2.5 inch discharges
Only one
What size pipe must supply 1.5-2” discharges
At least 2”
For water tanks less than 1000 gallons the tank fill valve pipe must be how big
At least 1”
For water tanks greater than 1000 gallons in the tank fill line must be at least how large
At least 2 inches
A valve that circulates water back through the tank or dumps onto the ground to keep the pump cool
Circulator valve or recirculator valve
For prolonged operations it may be necessary to do what to keep the pump and water cool
Discharge water through a dump line or hose on the ground.
NFPA requires all intake or discharges that are 3 inches or greater be equipped with a slow acting control valve to reduce water hammer. Opening action shouldn’t take less than how long
3 seconds
What can be used to drain the line if the hose is unable to be bled off
Discharge drain valve
In order to drain booster hose during freezing temperatures may be necessary to do what in addition to opening the drain
Unravel and drain the hose
How fast does a pressure relief valve need to kick in
3-10 seconds after pressurize
Pressure relief valve must prevent pressure from exceeding how many psi above the set level
30 psi
Two types of pressure relief valve
Leave on discharge side. Relieve pressure on intake side.
Most common pressure relief valve
Pilot valve that opens and reroutes water back to the intake
Although pressure relief valves Quick to react they are somewhat slower to
Reset back to the closed position
Is generally recommended that the intake relief valve be set to open when the intake pressure rises more than how many PSI above necessary operating pressure
10 psi
Pressure control device that controls engine speed eliminating hazardous conditions that result from excess pressure’s
Pressure governor
Electronic governors also feature cavitation protection by returning the engine idle when intake pressure drops below how many PSI
30 psi
Most modern pumpers use what type of primer motor
Positive displacement rotary vein and rotary gear type
What must be checked in the oil reservoir for the priming pump to make sure it is free of dirt and so that it operates appropriately as the tank drained
Oil reservoir vent
an air primer uses the air compressor to supply air to a jet pump that creates what effect to prime the pump
Venturi affect
Although not required what to gauges or indicators are recommended for installation on the pump panel
Automatic transmission temperature gage, fuel level
Two primary gauges operator uses to determine water pressure entering and leaving pump
Master intake and discharge gauge
The master intake and discharge gauge is usually calibrated from 0 to 600 PSI and what level to indicate vacuum
0-30 inches of mercury for vacuum on the negative side
When drafting as the pump speed increases demand increases on the draft, when the vacuum reading approaches what reading, the pump is nearing its capacity and unable to supply additional lines
20 inches of mercury negative
What is allowed to be used as a substitute for individual pressure discharge gauges
Flowmeter readouts
Even with a flowmeter system and use the apparatus is still required to have what
Master intake and master discharge pressure gauges
Throttle lock that can be turned clockwise or counterclockwise to achieve pressure is also known as
Vernier throttle
The primary function of an auxiliary cooling system is to control the temperature of coolant in what during pumping operations
The apparatus engine
In extreme cases when the engine is overheating and the auxiliary cooling systems don’t work what can be done for a very brief time to cool the motor while interior crews withdraw
Directly hose line through the radiator of the motor
