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78 Cards in this Set

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Types of positive displacement pumps.

- Single action piston pump
- Double action piston pump
- Rotary Gear pump
- Rotary Vane pump
What is the most used type of pump for priming centrifugal pumps?
Rotary Vane
What classification is a centrifugal pump ?
nonpositive displacement pump
What two parts does a centrifugal pump consist of?
- Impeller
- Casing
How fast does an impeller rotate on a centrifugal pump?
2,000-4,000 rpm
The centrifugal pump capacity is dependent on what?
The size of the eye. The larger the eye, the greater the flow capacity.
The gradually increasing water passage outside of the impeller that leads to the discharge outlet of the pump.
The three main factors that influence a centrifugal fire pump's discharge pressure.
- Amount of water being discharged.
- Speed at which the impeller is turning.
- Pressure of water when it enters the pump form a pressurized source.
The greater the volume of water being flowed, the _____ the discharge pressure.
The greater the speed of the impeller, the _______ the pressure developed.
Doubling the speed of the impeller results in _____ times as much pressure if all other factors remain constant.
What are the two basic types of centrifugal pumps?
- Single-stage
- Two-stage
To minimize lateral thrust of large quantities of water entering the eye of the impeller, what type of impeller was developed?
Double Suction impeller
If a two stage pump, in parallel, is rated to flow 1000gpm at 150psi, How many gpm does each impeller supply?
500 gpm
When pumping in series, the total amount of water that can be delivered is limited by what?
The amount that one impeller can supply.
The process of switching between pressure and volume, on a multi-stage pump, is referred to as what?
At lower flow rates, operating in the series position reduces what?
The load and required RPM of the engine.
Switching form volume to pressure, in a multi-stage pump, results in an immediate ________ of the previous discharge pressure.
What is the maximum recommended pressure for operating a transfer valve on a multi-stage pump?
50 psi
If here is any question as to the proper operation of the transfer valve, it is better to be in the ________ than in ______.
parallel; series
A very close tolerance must be maintained between the pump casing and the hub of the impeller. This opening is limited to how much?
.01" or less
Power-operated transfer valves can be operated at pressures as high as what?
200 psi
What is the first indication that wear on the pump case and impeller is becoming a problem?
Increased RPM s needed to pump the rated capacity in pump tests.
What is the result of allowing water to churn in the pump, without flow, for extended periods of time?
The water in the pump becomes hot and the metal parts tend to expand causing excess wear on the pump.
The driver/operator can check pump temperature by doing what?
Placing hand on the direct pump intake pipe of the pump.
If packing is too tight, water is not allowed to flow between the packing and the shaft. What is the result of this condition?
excessive heat build-up
After periods of dryness, adjustments to the pump packing should not be made until what has been done?
The pump has been operated under pressure and the packing has had chance to seal properly.
When deciding on mounting arrangements and pump drive systems, for building a pumper, what should be considered?
- Cost
- Appearance
- Space required
- Ease of maintenance
- Tradition
- Use that the system receives
What are the most common applications for auxiliary engine driven pumps?
- ARFF vehicles
- Wildland Fire apparatus
- Mobile water supply apparatus
- Trailer-mounted fire pumps
- Portable fire pumps
What is the pumping capacity of most skid-mounted assemblies on small attack fire apparatus?
500 gpm
Auxiliary engine-driven umps used on ARFF apparatus and for trailer-mounted applications tend to be large capacity pumps rated to what?
4000 gpm or more
Where are trailer mounted pumps usually used?
Industrial and fire training facilities
If an apparatus is designed for pump and roll operations, where should there be a pressure gauge mounted?
In the cab in full view of the driver
If an apparatus is in a pump and roll operation, how should t be driven while hoselines are deployed?
Driven by the pressure gauge instead of the speedometer.
Conventional PTO units limit the capacity of the pump to what?
500 gpm
Why is the horsepower to a PTO limited to approximately 95?
Because the PTO is mounted on the side of the transmission and that is the limits of what the housing can take?
What are two disadvantages to front mount pumps?
- They are more susceptible to freezing temperatures.
- Obstruct the airflow through the vehicles radiator.
On midship pumps when the power is diverted to the pump, instead of the rear axle, The gear ratio is arranged so that the impeller turns how much faster than the engine?
1-1 1/2 times faster
With the engine idling and pump engaged, most speedometers read what?
10-15 mph
What is a disadvantage to rear-mount pumps?
The Driver/operator may be more directly exposed to oncoming traffic than other pump positions.
According to what NFPA standard should all components of the piping system be of a corrosion-resistant material?
NFPA 1901
The piping system as well as the pump must be able to withstand a hydrostatic test of what pressure before being placed into service?
500 psi
What are the two ways water can enter a pump?
- Through piping from an onboard tank.
- Piping connecting the pump to an outside pressurized water source
NFPA 1901 states that pumpers with a capacity of 500 gpm or less should be able to flow ___ gpm form their booster tank.
250 gpm
NFPA 1901 states pumpers with a capacity greater than 500 gpm should be able to flow at least how many GPM form their booster tank?
500 gpm
Why are all intake lines on a centrifugal pump located below the eye of the impeller?
Because the Priming pump is tapped into the pump at the highest point possible to remove all air from the system when drafting.
What intake pipe is the single exception to being below the eye of the impeller?
The tank to pump line which is gravity fed.
What should be considered to be auxiliary intakes to the pump-panel-mounted gated intakes unless they have been certified by the manufacturer?
Front and rear intakes
Pumps of what capacity or greater may require more than one intake connection?
1500 gpm or greater
All apparatus with a pump capacity of 750 gpm or greater are required to have how many 2 1/2 discharges?
Discharges larger than what are ma not be located on the pump operator's panel?
2 1/2 inches
Discharges to which 1 1/2 - 2" handlines are attached must be supplied by at least what size piping?
2 inch
All valves shoud be designed so they are easily operable at pressures of up to what?
250 psi
NFPA 1901 requires that tanks <1000 gallons have a __" fill line and >1000 gallons have at least a __" fill line
1" ; 2"
What is the most common type of valve found on a fire pump?
ball-type valve
NFPA 1901 requires that all intakes or discharges greater than 3" have what type of valves?
Slow acting valve controls
Where should drains be supplied?
The lowest point on the pump and lowest points on each line connected to it.
NFPA 1901 requires some type of pressure control device that must operate within what amount of time after the discharge pressure rises?
3-10 seconds
What are the two basic concepts for pressure relief valves?
- Those that relieve pressure on the discharge side of the pump.
- Those that relieve pressure on the intake side of the pump.
While discharge pressure relief valves are quick to react to over pressure conditions, they are sometimes slower to do what?
Reset back to "all closed" positions
What are the two basic kinds of pressure relief valves?
-Supplied by the manufacturer ad an integral art of the pump intake manifold.
- Add-on device that is screwed onto the pump intake connection.
It is generally recommended that intake valves be set to open when the intake pressure rises more than __psi above the desired operating pressure.
10 psi
Newer apparatus may be equipped with electric governors. These use a pressure sensing element connected to the discharge manifold called what?
Pressure Transducer
Electric governors are so accurate and quick to respond that they virtually eliminate the need for the pump to be equipped with what?
Discharge pressure relief valve
Primers fall into what three categories?
- Positive displacement
- Exhaust
- Vacuum
Which requires a higher RPM to operate? Rotary Vane primer or Rotary Gear primer?
Rotary Vane Primer
Engine driven primers should generally be able o operate with engine speeds of what?
1,000-1,200 RPM
NFPA 1901 requires the what controls to be on the operator's pump panel?
- Master pump intake pressure
- Master pump discharge pressure
- Engine Tach
- Engine coolant temp
- Engine oil pressure indicator
- Pump pressure controls (discharge valves)
-Engine throttle
- Primer control
- Tank to pump valve
- Tank fill valve
- Water tank level indicator
What is not required by NFPA 1901, but recommended to be located on the operator's pump panel?
- Engine fuel gauge
- Automatic transmission temperature gauge
What type of gauge should be on the intake side of the pump?
Master Intake gauge
(also referred to as the vacuum or compound gauge)
What is the master intake gauge usually calibrated to?
0-600 psi positive pressure
0-30 inches mercury (vacuum) negative pressure
The Master Pump Discharge pressure gauge should measure ___psi unlessthe pumper is equipped to supply high-pressure fog streams; in which case the gauge may be calibrated up to ____psi.
600si ; 1000psi
What indicates wear in the pump and the need for repairs?
A gradual increase in the amount of RPM required to pump the rated capacity.
When can overheating of the pump occur?
When it is ran for prolonged periods of time when no water is being discharged.
The throttle knob is also called what?
What is the most reliable way to insure that the water tank is full?
Visually check it during your routine daily inspection.
What are the two types of auxiliary coolers commonly found on older apparatus?
- Marine type
- Immersion type
In situations where a dramatic failure of a radiator hose or other cooling system element occurs while the pumper is supplying hoselines for crews in dangerous positions, what can be done to keep the operation up for a short time?
A hoseline can be directed onto the engine to maintain some form of cooling.