Chapter 9 - Fire Pump Theory Flashcards
- Self-priming pump that utilizes a piston or interlocking rotors to move a given amount of fluid through the pump chamber with each stroke of the piston or rotation of the rotors. Used for hydraulic pumps on aerial devices’ hydraulic systems and for priming on centrifugal fire pumps.
Positive Displacement Pump
p 295
Modern fire department pumpers are equipped with _____________ pumps as their main pump.
centrifugal
p 296
_________ pumps operate using a piston that moves back and fourth in a cylinder.
Piston pumps
p 296
- Positive-displacement pump using one or more reciprocating pistons to force water from the pump chambers.
Piston Pump
p 296
From the standpoint of design, _________-_______ are the simplest of all fire apparatus pumps.
rotary-type
p 296
_________ _______ pumps consist of two gears that rotate in a tightly meshed pattern inside a watertight case.
Rotary gear
p 296
The total amount of water that can be pumped by a rotary gear pump depends on the ?
size of the pockets in the gears and the speed of rotation
p 297
The rotary gear pump is a positive displacement pump because each pocket in the gears contains a ?
definite amount of water, which is forced out of the pump each time the gears turn with a positive action.
p 297
To prevent damage to the casings, most gear pumps feature gears made of __________ or another soft metal, while strong alloy such as _______ _______ is used for the pump casing.
bronze / cast iron
p 297
___________ ______________ pumps are self-priming, deliver a definite volume of water or air, and exhaust air from the pump and deliver water.
Positive displacement pumps
p 295
__________ ________ pumps are constructed with moveable elements that automatically compensate for wear, maintaining a tighter fit with closer clearances as the pump is used.
Rotary vane
p 298
This pump is one of the most common types of pumps used to prime a centrifugal fire pump?
Rotary vane pump
p 298
- Type of positive displacement pump commonly used in hydraulic systems. A rotor with attached vane is mounted off-center inside the pump housing; pressure is imparted on the water as space between the rotor and the pump housing wall decreases.
Rotary Vane Pump
p 298
Rotary Vane Pumps:
The distance between the _________ and the __________ is much greater at the intake than at the discharge.
rotor / housing
p 298
Rotary pumps are prone to failure if not ?
exercised regularly
p 298
Nearly all modern fire apparatus feature a ____________ pump as their main pump.
centrifugal
p 298
- Pump with one or more impellers that rotate and utilize centrifugal force to move the water. Most modern fire pumps are of this type.
Centrifugal Pump
p 298
Centrifugal Pumps:
This pump is classified as a _____________ displacement pump as it does not pump a definite amount of water with each revolution.
nonpositive
p 298
Centrifugal Pumps:
The pump imparts ___________ to the water and converts it to ___________ within the pump itself.
velocity / pressure
p 298
The operation of a centrifugal pump is based on the principle that a rapidly revolving disk tends to throw water introduced at its ?
center toward the outer edges of the disk
p 299
Centrifugal Pumps:
The __________ acts as the disk receiving its water through the ______ in its center.
impeller / eye
p 299
- Vaned circulating member of the centrifugal pump that transmits motion to the water.
Impeller
p 299
- Intake orifice at the center of a centrifugal pump impeller.
Impeller eye
p 299
Centrifugal Pumps:
The _________ of the impeller dictates the amount of pressure that is developed.
speed
p 299
Centrifugal Pumps:
The faster the disk is turned, the harder the water is thrown, giving the water more __________.
velocity
p 299
Centrifugal Pumps:
The volume capacity of the pump is dictated by the size of the ?
impeller
p 299
Centrifugal Pumps:
A larger impeller has a larger eye, allowing greater ?
flow capacity
p 299
Centrifugal Pumps:
The off-center mounting of the impeller within the casing creates a water passage of gradually increasing size as it nears the discharge outlet of the pump. This section of the pump is called the _________.
volute
p 299
- Spiral, divergent chamber of a centrifugal pump in which the velocity energy is given to water by the impeller blades is converted into pressure.
Volute
p 299
Three main factors influence a centrifugal fire pump’s discharge pressure:
- Amount of _________ being discharged
- ________ at which the impeller is turning
- Pressure of water when it enters the pump from a _____________ source
- water
- speed
- pressurized
p 300
Centrifugal Pumps:
For example with all other factors remaining constant, doubling the speed of the impeller will result in _______ times as much pressure.
four
p 300
A centrifugal pump is unable to pump ______ and is not ______-____________.
air / self-priming
p 300
There is a phenomenon of _____________ due to recirculating in single-stage pumps, where excess capacity is not allowed to escape the impeller area. This may lead to pump damage.
cavitation
p 300
Pumps used in the fire service constructed with a single impeller are referred to as ?
single-stage centrifugal pumps
p 300
Single-stage centrifugal pumps:
These may consist of front-mount pumps, power take off, auxiliary engine driven, and midship pumps that use a single intake impeller and a simple casing to provide flow capacities up to _________ gpm.
2,250 gpm
p 300
_____________ centrifugal pumps have an impeller for each stage mounted in a single housing.
Multistage
p 301
Multistage centrifugal pumps:
When the pump transfer valve is in the volume position, each of the impellers takes water from a source and delivers it to the discharge. This is know as pumping in the ?
parallel (volume) position
p 301
Multistage centrifugal pumps:
When the transfer valve is set in the pressure position, all water from the intake manifold is directed into the eye of the first impeller. This is know as pumping in ?
series (pressure) position
p 302
Setting the transfer valve to series greatly increases the maximum ____________ that may be attained; however increasing the ___________ results in a corresponding loss in ___________.
pressure / pressure / volume
p 302
The process of switching between pressure and volume is sometimes referred to as “_______________”.
“changeover”
p 302
Switching from volume to pressure can result in the immediate doubling of the previous ?
discharge pressure
p 302
The maximum net pump discharge pressure at which the _____________ valve may be safely operated varies by manufacturer and age of the pump.
transfer valve
p 302
If there is any question as to the correct position of the transfer valve, it is best to operate in ___________ rather than _________.
parallel (volume) / series (pressure)
p 303
In the parallel mode, the pump will be capable of supplying 100 percent of its rated capacity at ______ psi at _____ feet of lift with _____ feet of suction hose while drafting.
150 psi / 10 feet / 20 feet
p 303
___________ (________) valves are essential to the operation of a multistage pump.
Clapper (check) valves
p 304
- Hinged valve that permits the flow of water in one direction only.
Clapper Valve
p 304
- Automatic valve that permits liquid to flow in only one direction. For example, the inline valve that prevents water from flowing into a foam concentrate container when eduction pressure is disrupted.
Check Valve
p 304
A very close tolerance must be maintained between the pump casting and the hub of the impeller. This opening is usually limited to _____ inch or less. Any increase in the opening lessens the effectiveness of the pump.
.01 inch or less
p 304
To restore the pumping capacity without replacing the entire pump, _______ rings or __________ rings in the pump casing may be replaced to maintain the preferred spacing between the hub of the impeller and the pump casing.
wear rings or clearance rings
p 304
- Replaceable rings that are attached to the impeller and/or the pump casing to allow a small running clearance between the impeller and pump casing without causing wear of the actual impeller or pump casing material.
Wear Rings
p 304
Newer model centrifugal pumps may be equipped with a __________ _________ valve that opens to allow overheated water to circulate between the pump and the main water tank or into the atmosphere.
thermal relief valve
p 306
The driver/operator can check for excessive pump temperature manually by placing a hand on the direct pump intake pipe. If it is warm to the touch, the driver/operator should open a ?
discharge, tank fill, or circulator valve
p 306
When operating a pump not equipped with a thermal relief valve, the best course of action to prevent overheating is to ensure that ?
some water is moving through the pump at all times
p 306
Pump impellers are fastened to a shaft that connects to a ____________ ________. The transmission transfers the required energy to spin the impellers at a very high rate of speed.
transfer case
p 306
_____________ seals are the most common type in use today.
Mechanical
p 306
Pumps powered by gasoline or diesel engines independent of the vehicle-drive engine are examples of ____________ pumps.
auxiliary pumps
p 307
Although used on some structural fire fighting pumpers, the most common applications for auxiliary engine driven pumps are:
- ___________ rescue fire fighting vehicles
- ______________ fire apparatus
- _________ water supply apparatus
- _________ mounted fire pumps
- ___________ fire pumps
- Airport (ARFF)
- Wildland
- Mobile
- Trailer
- Portable
p 307
- Mechanism that allows a vehicle engine to power equipment such as a pump, winch, or portable tool; it is typically attached to the transmission.
Power Take-Off (PTO) System
p 307
- Ability of an apparatus to pump water while the vehicle is in motion.
Pump and Roll
p 308
In the past, conventional PTO units were limited to powering pumps up to approximately ______ gpm. However, some manufacturers now provide full torque power take-offs that allow for the installation of pumps as large as ________ gpm. This type of PTO is commonly used with automatic transmissions where the __________ of the engine drives the PTO unit.
500 gpm / 1250 gpm / flywheel
p 308
Some fire department pumpers feature an extended front bumper with a pump mounted between the __________ and the _________ of the vehicle.
bumper / grill
p 308
- Fire pump mounted in front of the radiator of a vehicle and powered off the crankshaft.
Front-Mount Pump
p 309
One major disadvantage of the front-mount pump is susceptibility of the pump and gauges ?
freezing in cold weather due to their exposed position.
p 309
During warm weather operations, front-mount pumps may obstruct ___________ through the vehicles radiator and may contribute to overheating.
airflow
p 309
Most fire departments operate pumpers that feature the pump mounted laterally across the frame behind ?
These pumps are called ________ pumps.
the engine and transmission / midship
p 309
Midship Pumps:
The gear ratio is arranged so that the impeller turns faster than the engine, usually _____ to _____ times as fast.
1 1/2 to 2 1/2 times as fast
p 310
With the engine idling and the pump engaged, most speedometers will indicate between _____ to _____ mph.
10 to 15 mph
p 310
Apparatus with ______-________ pumps are becoming increasingly popular.
rear-mount
p 312
Rear-Mount Pumps:
This design offers a number of advantages, including a more even weight distribution on the __________ and more useable ______________ space.
chassis / compartment
p 312
The primary parts of the piping system are ________ and __________ piping as well as pump _______ and _________.
intake and discharge / drains and valves
p 312
NFPA _______ requires all components of the piping system be of corrosion resistant material.
NFPA 1901
p 312
The piping system and the fire pump itself must be capable of withstanding a hydrostatic test of ______ psi before being placed into service.
500 psi
p 312
In order to minimize pressure loss within the apparatus, all piping and hoses must be deigned to run as ?
straight as possible with a minimum number of bends or turns
p 312
Intake Piping:
According to NFPA 1901 pumpers with a capacity of 500 gpm or less should have piping capable of flowing ______ gpm. Pumpers with a capacity greater than 500 gpm should be able to flow at least ______ gpm.
250 gpm / 500 gpm
p 312
Intake Piping:
Many pumpers are equipped with tank-to-pump as large as ___ inches in diameter.
4 inches
p 312
The tank-to-pump valve must be maintained in proper condition, as a leak in this valve will not allow the pump to be ?
primed if the tank is empty
p 312
Fire apparatus pumps must be capable of being supplied from ?
external pressurized and static sources
p 313
When using a static source, prime the pump by removing all or most of the ?
air from the pump, lowering the atmospheric pressure within the pump casing.
p 313
Intake piping is round in shape at the point where the intake hose connects to it. As the piping nears the pump itself, it typically tapers to a _________ shape in order to eliminate the vortex that may occur in water that flows through circular piping.
square shape
p 313-314
Unless they have been certified by the manufacturer to deliver rated capacity, front and rear intakes should be considered ___________ intakes in the same manner as the pump panel mounted gated intakes.
auxiliary
p 314
Additional intake lines, usually gated, are provided for use in ________ operations, or when water is received through small diameter ________ _______.
relay operations / supply hose
p 314
Based on NFPA ______, a sufficient number of _____ inch discharge openings must be provided to flow the rated capacity of the pump.
NFPA 1901
2 1/2 inch
p 314
As a minimum, all fire apparatus with a rated pump capacity of 750 gpm or greater must be equipped with at least _____ 2 1/2 inch discharges.
two
p 314
Pumps rated less than 750 gpm are required to have only ______ 2 1/2 inch discharge.
one
p 314
Discharges greater than 2 1/2 inches in diameter may not be located on the ?
pump operators panel
p 314
A minimum of ____ inch piping, valves, and elbows must be used to supply discharges where 1 1/2, 1 3/4, or 2 inch handlines are attached.
2-inch
p 314
When multiple attack lines that require different pressures are being operated, the driver/operator must set the engine discharge pressure to the ?
highest level needed
p 314
A _______ _______ line should be provided from the discharge side of the pump.
tank fill line (or tank recirculating valve)
p 315
According to NFPA 1901, apparatus with tanks of less than 1000 gallons must have a tank fill line of at least ____ inch in diameter. Tanks greater than 1000 gallons must be provided with at least a _____ inch tank fill line.
1-inch / 2-inch
p 315-316
On pumps not equipped with a thermal relief valve, the ______ ______ line can be used in conjunction with the ______-___-______ valve to circulate water through the pump to prevent overheating when no water is flowing.
tank fill line / tank-to-pump valve
p 316
________ control most of the intake and discharge lines from the pump.
Valves
p 316
Valves must be constructed to be _________ and ________ resistant.
airtight and wear
p 316
The most common type of valve is the ______-type valve that permits the full flow of water through a line with minimum friction loss.
ball-type valve
p 316
_______ or ____________ valves are also used on fire apparatus. These are commonly used on large-diameter intakes and discharges.
Gate or butterfly valves
p 317
NFPA 1901 requires that all intakes or discharges that are _____ inches or greater be equipped with slow acting valve controls. This feature prevents the valve movement from open to close (or vise versa) in less than _____ seconds.
3 inches / 3 seconds
p 317
______________ _____________ regulation is essential to ensure the safety and effectiveness of personnel operating hoselines.
Automatic pressure
p 318
NFPA _______ requires some type of pressure control device to be part of any fire apparatus pumping system.
NFPA 1901
p 318
Automatic Pressure Control Devices:
This device must operate within ________ to ______ seconds after the discharge pressure rises and restrict the pressure from exceeding ______ psi above the set level.
three to ten seconds
30 psi
p 318-319
The main feature of a ________ valve is its sensitivity to pressure change and its ability to relieve excessive pressure within the pump discharge.
relief valve
p 319
There are two basic concepts for pressure relief valves:
- Those that relieve excess pressure on the __________ ______ of the pump.
- Those that relieve excess pressure on the _________ _______ of the pump.
- discharge side
- intake side
p 319
Although there are several types available, the most common relief valve uses a _________-____________ _________ valve.
spring-controlled pilot valve
p 319
It is generally recommended that the intake relief valves be set to open when the intake pressure rises more than _____ psi above the necessary operating pressure.
10 psi
p 320
The ______________ _____________ is designed to regulate the engine speed to match the pump discharge requirements.
pressure governor
p 321
- Pressure control device that controls engine speed, eliminating hazardous conditions that result from excessive pressures.
Pressure Governor
p 321
Excessive pressure is generally caused by shutting down one or more ?
operating hoselines
p 321
The electronic governor also features ____________ protection by returning the engine to idle when intake pressure drops below ______ psi.
cavitation / 30 psi
p 321
- Condition in which pockets form due to localized regions of low pressure at the vanes in the impeller of a centrifugal pump, causing vibrations, loss of efficiency, and possibly damage to the impeller.
Cavitation
p 321
Another advantage of the electronic governor is that when a discharge line is closed the engine ______ is adjusted, but the same ____________ pressure is maintained on any lines still flowing. With a mechanical governor the same scenario would result in lower ____________ pressure for all lines as the engine rpm is lowered.
rpm / discharge / discharge
p 321
The ability to initiate a successful drafting operation depends on creating a __________ ____________ within the pump and intake hose than exists in the atmosphere.
lower pressure
This lower pressure will result in water being forced up into the intake hose and fire pump.
p 322
Modern centrifugal fire pumps are unable to create this condition. A ___________ ___________ is needed to create the vacuum that makes drafting possible.
priming device
p 322
- Any device, usually a positive-displacement pump used to exhaust the air from inside a centrifugal pump and the attached hard suction; this creates a partial vacuum, allowing atmospheric pressure to force water from a static source through the suction hose into the centrifugal pump.
Priming Device
p 322
Most modern pumpers use ___________ ______________ primers.
positive displacement
p 322
The operator manual supplied by the fire manufacturer should specify the preferred engine speed (rpm) for priming but, in general, the range is between _________ to _________ rpm.
1000 to 1200 rpm
p 322
Most new pumpers are equipped with ______-_______ primers.
oil-less
p 323
___________ primers are generally found on skid-mounted pumps or older fire apparatus.
Exhaust primers
p 323
What priming system uses the compressor to supply an airline to a jet pump that creates a Venturi Effect that primes the pump using no moving parts or lubricants?
Air priming system
p 324
- Physical law stating that when a fluid, such as water or air is forced under pressure through a restricted orifice, there is an increase in the velocity of the fluid passing through the orifice and a corresponding decrease in the pressure excerpted against the sides of the constriction. Because the surrounding fluid is under greater (atmospheric) pressure, it is forced into the area of lower pressure.
Venturi Effect
p 324
NFPA _______ requires that all controls and instruments necessary to operate the pump are located on the pump operators panel.
NFPA 1901
p 324
The ___________ __________ gauge is connected to the intake side of the pump and measures either positive pressure or a vacuum.
master intake gauge
p 324
The master intake gauge is usually calibrated from ____ to ______ psi of positive pressure and from _____ to ______ inches of mercury on the negative side.
0 to 600 psi / 0 to 30 inches
p 324
Master intake:
When the vacuum reading approaches _____ inches, the pump is nearing its capacity and is not able to supply additional lines.
20 inches
p 325
The master intake gauge also provides a reading of the _____________ pressure when the pump is operating from a hydrant or is receiving water through a supply line from another pumper.
residual pressure
p 325
The _______________ displays the engine speed in revolutions per minute.
tachometer
p 326
The _____________ provides a relative indication of battery condition, and the __________ indicates the status of the vehicle’s alternator and charging system.
voltmeter / ammeter
p 326
- Device used for measuring existing voltage in an electrical system.
Voltmeter
p 326
- Gauge that indicates both the amount of electrical current being drawn from and provided to the vehicles battery.
Ammeter
p 326
_________ ____________ indicators, commonly called discharge gauges, may be connected to the individual discharge outlets of the fire pump.
Pump pressure
p 327
A ____________ __________ ___________ must be contained on the pump operator’s panel. This device is used to increase or decrease the _______ of the engine that powers the fire pump.
pumping engine throttle / speed
p 327
In extreme situations where a dramatic failure of a radiator hose or other cooling element has occurred while the pumper is supplying hoselines for interior fire fighting crews, a _________ _________ may be directed at the engine to maintain some form of cooling for a very brief time while interior crews are with drawn to safety.
water stream
p 329-330
Early pumps used by the fire service were hand-operated _______ pumps. _______ pumps followed, using a hand crank to rotate a gear, forcing water through the pump and hoses. ________ and _________ action piston pumps of various diameters and strokes replaced ________ pumps. These pumps are referred to as ?
piston / rotary / single and double / rotary / positive displacement pumps
p 295
___________ ______________ pumps are self-priming, deliver a definite volume of water or air, and exhaust air from the pump and deliver water. These pumps are “___________ ______ __________” in that they produce the same flow at a given speed regardless of discharge pressure.
Positive displacement pumps / “constant flow machines”
p 295
Modern fire department pumpers are equipped with ___________ pumps as their main pump.
centrifugal
p 296
Although the positive displacement pump has been replaced by the centrifugal pumps as the main pumping unit of fire apparatus, positive displacement pumps continue to serve a vital role on modern apparatus because of their ability to pump _____ and ______.
air and foam
p 296
Piston Pumps
These multicylinder, PTO-driven pumps can provide pressure up to _______ psi for high pressure fog lines, or to inject foam concentrate into a water line or manifold at a ________ pressure than the water pump is creating.
1000 psi / higher
p 296
Rotary gear pumps
The gears are constructed so that they ________ each other and are in close proximity to the ______.
contact / case
p 296
Rotary gear pumps
If the pump tries to move more water than the discharge lines can take away pressure builds up. A ____________ ________ device must be provided to handle excess pressure.
pressure relief device
p 297
Rotary vane pumps
The vanes are free to move within the slot where they are mounted. As the rotor turns, the vanes are forced against the housing by _____________ force.
centrifugal force
p 298
Rotary vane pumps
When the surface of the vane that is in contact with the casing becomes worn, centrifugal forces causing it to ?
extend further, causing it to maintain a tight fit
p 298
A centrifugal pump contains an impeller assembly with the _________, _____, and ______.
impeller, shaft, and seals
p 299
Centrifugal pumps
The speed at which the impeller rotates is based upon the ________ ________ configuration.
power train
p 299
Centrifugal pumps
Greater pressure is developed with increased _________ speed.
impeller
p 300
Multistage centrifugal fire pumps
The impellers are usually mounted on a single ______ driven by a single _______ _______.
shaft / drive train
p 301
Why does setting the transfer valve to series (pressure) result in much higher pressure than the parallel option?
Because the same stream of water has passed through two impellers with each boosting the pressure.
p 302
Centrifugal pumps - series (pressure) position
With only one impeller delivering the water to pump discharge port, the volume of water available while operating in pressure position is limited to the amount that ?
one impeller can supply
p 302
Any ___________ on the fireground must be carefully coordinated with attack crews so that they will be prepared for a slight interruption during transfer.
changeover
p 303
Operation of the transfer valve is performed __________ on many older two-stage pumps. These pumps feature a safeguard making it physically impossible to accomplish the transfer while pumping at a _______ __________.
manually / high pressure
p 303
Newer pumps use a ________-__________ transfer valve.
power-operated
p 303
Many power operated transfer valves operate at pressures as high as _____ psi.
200 psi
p 303
Should a valve stick open or closed, or be hampered by debris, the pump will not operate properly in ________ (__________). When the transfer valve is operated, water allowed to escape back into the intake will churn through the pump instead of building up ___________.
series ( pressure ) / pressure
p 303
Particles of _______ passing between the impeller and pump casing act like an abrasive and wear down the metal surfaces. As gaps increase, greater amounts of water are allowed to slip back into the ________ and are not available at the _________.
sand / intake / discharge
p 304
Centrifugal pumps:
Most manufactures recommend the pump to be __________ between fire calls, especially in cold weather conditions.
drained
p 306
_______ driven fire pumps are most common to initial attack, wildland, or mobile water supply applications. In recent years, they are becoming widely used on structural apparatus pumpers.
PTO
p 307
Some manufacturers offer a ______-________ PTO design that is driven off the engines flywheel.
rear-engine
p 307
The PTO pump does permit _______ and _______ operation, but it is not as effective as the separate engine unit.
pump and roll
p 308
Most _______-________ pumps are engaged and operated from the pump location in front of the apparatus. This may put the D/O in a ____________ position directly in front of the vehicle.
front-mount / vulnerable
p 309
Midship Pumps
The maximum capacity that can be obtained by this system is limited only by the engine ____________ and size of the ______.
horsepower / size
p 310
A disadvantage of the rear-mounted pump is that the D/O may be more directly exposed to ?
oncoming traffic than in other pump-mounting positions
p 312
Water may enter the fire pump either from piping that connects the pump to the __________ water tank or the piping that connects the pump to an _________ water supply.
onboard / external
p 312
The primary intake into the fire pump is through ?
large diameter piping and connections
p 313
Most pump connections are equipped with ______ valves on the line side of the control valves.
drain
p 317
Another purpose for pump and suction drains is to remove all the water from the system in climates where _________ may occur.
freezing
p 318
__________ valves on the intake pressure relief valve allow air to bled off as an incoming supply hose is charged.
Bleeder
p 320-321
Pressure Governor
Because the speed of the impellers determines the pressure, and the engine speed determines the speed of the impellers, it is only necessary to reduce ?
engine speed to reduce pressure
p 321
Pressure Governor
When excessive pressure builds up, a tube from the discharge side of the pump transmits the resulting pressure rise to a governing device, which then cuts back the _________.
throttle
p 321
Newer pumpers are often equipped with ___________ governors. These devices use a pressure sensing element ( pressure transducer ) that is connected to the discharge _____________.
electronic / manifold
p 322
Another advantage of the electronic governor is that when a discharge line is closed the engine rpm is adjusted, but the same ___________ ___________ is maintained on any lines still flowing.
discharge pressure
p 321
A __________ _______ discharge pressure gauge is also required on a pumper to reflect overall discharge pressure.
master pump
p 325
NFPA 1901 allows ___________ readouts to substitute for individual pressure discharge gauges.
flowmeter
p 327
The most common type of water level indicator uses a series of ?
lights on the pump operators panel
p 328
The primary function of an auxiliary cooling system is to control the the temperature of ___________ in the apparatus engine during pumping operations.
coolant
p 329
