Pumps and Hydraulics Flashcards
What is the definition of hydraulics?
The study of physical characteristics exhibited by fluids at rest and in motion
What is the definition of hydrostatics?
Fluids at rest
What is the definition of hydrokinetics?
Fluids in motion
What is the definition of friction loss?
The part of the total pressure that is lost while forcing water through pipes, fittings, hose, and adapters
What is the definition of engine pressure?
Pressure that must be developed at the apparatus to overcome friction loss, elevation, and provide the correct nozzle pressure
What is the definition of net engine pressure?
Engine pressure minus any intake pressure
What is the definition of nozzle pressure?
Pressure that must be delivered to the nozzle in order for the nozzle to function properly and lfow th ecorrect amount of water
What is the definition of water hammer?
Force transmitted through a fluid when an obstruction is placed quickly in the path of flow
What is the definition of cavitation?
Bubbles of vapor created in the pump that pass from negative to positive pressure, then collapse or implode
I’m not going to include any of the history stuff since he said it wouldn’t be on the test kk?
KK
How much does one gallon of fresh water weigh?
8.35lbs
How many cubic inches is one gallon of water?
231ci
How many cubic inches are in a cubic foot of water?
1728ci
How many gallons are in 1 cubic foot of water?
7.418 gallons
How much does 1 cubic foot of water weigh?
62.5lbs
Which NFPA is the Standard on Fire Pumps?
1901
What are the 3 tests a class A pumper needs to pass?
100% of rated capacity @150psi
70% of rated capacity @200psi
50% of rated capacity @250psi
Pumpers will have one ____” outlet for every ____GPM
2 1/2”
250
What is the rated capacity of our trucks?
1250GPM
5 outlets
What does a fire pump do?
Boost pressure
Duh
What are the 5 times that the pumps are tested?
By manufacturer By UL or FM Upon delivery Annually After extensive maintenance
What is the difference between positive displacement and non-positive displacement pumps?
Positive displacement pumps can move air, non-positive displacement pumps cannot
What are the 2 types of positive displacement pumps?
Piston and rotary
How does a double action piston type pump operate?
It pushes water on both the forward and return strokes
What are the 2 types of rotary pumps?
Rotary gear and rotary vane
What kind of pump do our fire engines have?
Non-positive displacement centrifugal pump
What is the most common type of pump used in the fire service?
Non-positive displacement centrifugal pump
A non-positive centrifugal pump does or does not pump a definite amount of water with each revolution?
Does NOT
What is the biggest advantage of a centrifugal pump?
It can utilize incoming pressure
What are the 2 basic components of the pump?
Casing
Impellers
What is the casing constructed of?
Fine grain alloy and cast iron
What is the minimum tensile strength of the casing?
30,000psi
What is a feature of the casing that allows for easy removal of the impeller assembly?
It is split into 2 sections
What is the impeller made of?
What is the shaft made of?
High quality bronze construction
Stainless steel
At the center of the vanes is called the ____
Eye
The vanes on both sides are covered by ____ which….
Shrouds which confines the water within the vane pockets
What are the 5 pump mounting and drive arrangements?
Auxiliary engine driven (brush truck) Cross-mounted engine Power take-off (pump and roll) Front mount Mid-ship mount
What kind of Pump mount and drive arrangement do our engine have?
Our ladders?
Mid-ship mount
Power take-off
With a power take-off type, what changes when the driver changes the vehicle speed?
The pump pressure
What does a power-take off type allow?
Pump and roll capability
With a power take-off drive, how is the pump driven?
By a driveshaft connected to the PTO on the chassis transmission
What does “Stages” refer to in a pump?
Number of impellers
All TFD pumpers are…
Hale, single stage, midship mounted pumps
In volume/parallel mode, each impeller receives ___ intake volume
1/2
During volume/parallel mode, both impellers pump to the ____ side of the pump
Discharge side
During volume/parallel mode, both impellers are capable of delivering __% of rated capacity
50%
In volume/parallel mode, the total GPM is equal to…
The sum of each impeller
In volume/parallel mode, the transfer valve between impellers is _____
Closed
When do we use volume/parallel mode?
When you want more than 50% of rated capacity
In pressure/series mode, what is the path of water through the pump?
Water is pumped from the first impeller through the open transfer valve to the second impeller then to the discharge
In pressure/series mode, the pump discharge volume remains _____
Constant
In pressure/series mode, the second stage impeller _____ the pressure
Doubles
When do we use pressure/series mode?
When less than 50% of rated capacity is needed
Does the engine work harder for pressure/series mode or for volume/parallel mode?
Volume/parallel mode
Engine does not work as hard during pressure/series
Name the 5 pump accessories
Pressure control devices Priming devices Discharge and intake valves Instrumentation and gauges Auxiliary coolers
What are the 2 pressure control devices?
Relief valve and governor
What is the purpose of a pressure control device?
Protect personnel and equipment from surges and rapid shut downs
What happens when hydrant water comes?
Pressure shoots up
What are the relief valves on the engine?
Standard relief valve
Separate intake and discharge relief systems
TPM relief system
What does a standard relief valve do?
Relieves excess discharge pressure back into the suction side of the pump
What does “TPM” mean for TPM relief valve?
Total pressure master
Which TFD pumpers have a TPM relief valve?
ALL TFD pumpers
What does the TPM relief valve do?
Relieves excess pressure from both discharge and intake sides of pump
Where is the sensing valve for the TPM relief valve?
Intake side of the pump
What does a blinking and a solid light mean on a TPM relief valve?
Blinking-relieving external
Solid-relieving internal
The impeller speed is determined by the…
Engine speed
Use ____ ____ to control excess discharge pressures
Engine speed
How does a pressure governor work?
Hydraulic line from discharge side of pump transmits pressure rise to a governing device which then cuts back throttle
Why are priming devices necessary/
Because centrifugal pumps are not capable of pumping air
What are the 3 categories of priming devices?
Positive displacement pumps
Exhaust pumps
Vacuum pumps
What are the 2 types of positive displacement primers?
Rotary vane
Rotary gear
What type of positive displacement primer do we use on all TFD apparatus?
Rotary vane
What drives the positive displacement primer?
Electric drive
There are 12 instrumentation and gauges listed, try to name them all…
Master pump intake gauge Master pump pressure gauge Tachometer Engine temp. gauge Engine oil pressure gauge Voltmeter Discharge valves Engine throttle Primer control Water "tank to pump" valve control Water "tank fill" valve control Water tank level indicator
What are the 2 types of gauges?
Pressure and compound
What is the difference between pressure and compound gauges?
Compound gauges read below 0 (vacuum)
On both gauges, pressure is measured by a gauge containing a closed, curved tube known as the ____ ____
Bourdon Tube
How does a Bourdon Tube work?
Water enters the open end of the tube and the tube tends to straighten. The tube is connected to a gear mechanism that controls the movement of the needle
What type of gauge is the master pump intake gauge?
Compound
psi on pressure side
0-30 in. Hg on vacuum side
What are the 2 auxiliary coolers?
Engine cooler Recirculating line (pump cooler)
Where is the engine cooler usually located?
In upper radiator hose
New pumpers installed near pump tranny
What does the recirculating line/pump cooler do?
Keeps pump water cool when pump in engaged and no water is flowing.
Recirculates water from pump to booster tank
What does cavitation sound like?
Gravel in the pump
What is cavitation caused by and what can it lead to?
Caused by running out of water or water getting too hot
Can lead to pump damage
Engine pressure formula
NP+FL+/-HP+AL
GPM formula
29.7xd(2)xsquare root NP
What is the square root of 50?
7.07
What is tandem pumping and where are they hooked up?
Two pumpers operating from one hydrant
Inlet to inlet
When is tandem pumping used?
When a single hydrant has more water available than is being utilized by a single pumper
When is relay pumping used?
When necessary to lay supply lines over long distance
Used to boost pressure
Relay pumping hooks up from ____ to ____
Outlet to inlet
With relay pumping, attempt to maintain ___lbs residual pressure
40
