Chapter 10 Fire Pump Theory Flashcards Preview

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Flashcards in Chapter 10 Fire Pump Theory Deck (84)
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1
Q

Positive displacement pumps have largely been replaced by ___ for use as the main fire pump on modern fire apparatus.

A

Centrifugal pumps

2
Q

Positive displacement pumps are used as ___ devices to get water into centrifugal pumps during drafting operations.

A

Priming

3
Q

The two basic types of positive displacement pumps are:

A

piston and rotary pumps.

4
Q

Piston positive displacement pumps may be:

A

single-acting or double-acting.

5
Q

The output of the piston positive displacement pump is determined by the size of the cylinder and the:

A

speed of the piston travel.

6
Q

The capacity of a piston positive displacement pump is usually determined by the size of the:

A

cylinder.

7
Q

Rotary positive displacement pumps are the ___ of all fire apparatus pumps in design.

A

simplest

8
Q

Rotary positive displacement pumps are now used as:

A

small-capacity, booster-type pumps, low-volume high pressure pumps, and priming pumps.

9
Q

The total amount of water that can be pumped by a rotary gear pump depends on the size of the ___ and the speed of rotation.

A

pockets in the gears

10
Q

Rotary vane pumps are constructed with moveable elements that automatically compensate for:

A

wear.

11
Q

The centrifugal pump is classified as a ___ because it does not pump a definite amount of water with each revolution.

A

nonpositive displacement pump

12
Q

The centrifugal pump imparts ___ to the water and converts it to pressure within the pump itself.

A

velocity

13
Q

The ___ of the centrifugal pump transmits energy in the form of velocity to the water.

A

impeller

14
Q

The ___ of the centrifugal pump collects the water and confines it in order to convert the velocity to pressure.

A

casing

15
Q

The ____ of the centrifugal pump is a water passage that gradually increases in cross-sectional area as it nears the pump discharge outlet.

A

volute

16
Q

The impeller in a centrifugal pump rotates very rapidly within the casing, generally from ___ rpm.

A

2,000 to 4,000

17
Q

The volume capacity of the pump is dependent on the size of the ___ of the impeller: The greater it is, the greater the flow capacity.

A

eye

18
Q

Which of the following is NOT a factor that influences a centrifugal fire pump’s discharge pressure?

A

A. Amount of water being discharged
B. Speed at which the impeller is turning
C. Size of the volute and impeller inside the pump*
D. Pressure of water when it enters the pump from a pressurized source

19
Q

What is changeover?

A

The process of switching between the pressure and volume position

20
Q

SOPs in some departments specify that the transfer valve stay in the pressure position until it is necessary to supply more than ___ the rated volume capacity of the pump.

A

one-half

21
Q

Most manufacturers specify that the pump may remain in the pressure system until it is necessary to flow more than ___ of the rated volume capacity.

A

two-thirds

22
Q

Most manufacturers recommend that the transfer valve should be operated at a maximum pressure of:

A

50 psi (350 kPa).

23
Q

While the parallel (volume) position may make it difficult to attain the desired pressure, it can supply ___ percent of the rated volume capacity at ___ psi (kPa).

A

100%, 150 psi (1 000 kPa)

24
Q

Any increase in the space between the pump casing and the hub of the impeller lessens the pump’s effectiveness. This opening is usually limited to ___ or less.

A

0.01 inch (0.25 mm)

25
Q

To restore pump capacity without replacing the pump itself, replaceable wear rings (or ___ rings) are provided in the pump casing to maintain the desired spacing.

A

clearance

26
Q

Packing rings are used to make a seal at the point where the shaft passes through the:

A

pump casing.

27
Q

The most common type of packing material is made of rope fibers impregnated with:

A

graphite or lead.

28
Q

As packing rings wear with the operation of the shaft, the ___ can be tightened and the leak controlled.

A

packing gland

29
Q

Which of the following are supplied to provide cooling and lubrication between the packing rings and shaft?

A

Lantern rings

30
Q

A small amount of ___ should leak out around the packing and prevent excessive heat buildup.

A

water

31
Q

If the pump is operated ___ for any length of time, it can damage the shaft.

A

dry

32
Q

Pumps equipped with ___ will not drip and will not require adjustment.

A

mechanical seals

33
Q

____ of mechanical seals may cause damage that necessitates immediate and complicated repair.

A

Freezing

34
Q

Which pumps are powered by a gasoline or diesel engine independent of an engine used to drive the vehicle?

A

Auxiliary engine-driven pumps

35
Q

Which pumps have power diverted from the rear axle by shifting of a gear and collar arrangement inside the gear box?

A

Midship pumps

36
Q

Which pumps can obstruct air flow through the vehicle’s radiator and contribute to engine overheating?

A

Front-mount pumps

37
Q

Which pumps change pressure when the driver changes the vehicle speed?

A

Power take-off driven fire pumps

38
Q

Which pumps do not have the ability to pump-and-roll?

A

Midship pumps

39
Q

Which pumps provide more even weight distribution on the apparatus chassis?

A

Rear-mount pumps

40
Q

Which pumps are supplied power through the use of a split-shaft gear case located in the drive line between the transmission and the rear axle?

A

Midship pumps

41
Q

Which pumps allow the apparatus to have more compartment space for tools and equipment?

A

Rear-mount pumps

42
Q

Which pumps are powered by special fuels such as jet fuel?

A

Auxiliary engine-driven pumps

43
Q

Which pumps are used on ARFF vehicles, wildand fire apparatus, and portable fire pumps?

A

Auxiliary engine-driven pumps

44
Q

Which pumps must be mounted correctly for dependable and smooth operation?

A

Power take-off driven fire pumps

45
Q

Which pumps are more susceptible to freezing in cold climates?

A

Front-mount pumps

46
Q

Which pumps are mounted between the front bumper and the grill?

A

Front-mount pumps

47
Q

Which pumps require that the clutch be disengaged and the road transmission be placed in neutral to prevent damage to the gears?

A

Midship pumps

48
Q

Which pumps are driven by a driveshaft that is connected to the PTO on the chassis transmission?

A

Power take-off driven fire pumps

49
Q

Which pumps are ideal for pump-and-roll operations?

A

Auxiliary engine-driven pumps

50
Q

Which pumps offer the maximum amount of flexibility?

A

Auxiliary engine-driven pumps

51
Q

Which pumps are mounted laterally across the frame behind the engine and transmission?

A

Midship pumps

52
Q

Which of the following is NOT a component of a piping system?

A

A. Impellers
B. Pump drains*
C. Intake piping
D. Discharge piping

53
Q

Which of the following is NOT a material used to construct piping systems?

A

A. Brass
B. Rubber*
C. Cast iron
D. Stainless steel

54
Q

Piping systems must be able to withstand a hydrostatic test of ___ psi (kPa) before being placed into service.

A

500 psi (3 450 kPa)

55
Q

Piping that connects the pump and the onboard water tank is called:

A

intake piping.

56
Q

Intake piping should be sized so that pumpers with a capacity of 500 gpm (1 900 L/min) or less should be capable of flowing ___ gpm (L/min) from the booster tank.

A

250 (950 L/min)

57
Q

Intake piping should be sized so that pumpers with a capacity greater than 500 gpm (1 900 L/min) should be capable of flowing at least ___ gpm (L/min) from the booster tank.

A

500 gpm (1 900 L/min)

58
Q

Intake piping may be as large as ___ inches (mm) in diameter.

A

4 inches (100 mm)

59
Q

Pumps that have a capacity of ____ gpm (L/min) or greater may require more than one large intake connection at each location.

A

1,500 gpm (6 000 L/min)

60
Q

Apparatus with a rated pump capacity of 750 gpm (2 850 L/min) or greater must be equipped with at least ___ 2½-inch (65 mm) discharge(s).

A

two

61
Q

Apparatus with a rated pump capacity less than 750 gpm (2 850 L/min) are only required to have ___ 2½-inch discharge(s).

A

one

62
Q

All discharge valves should be designed so that they are easily operable at pressures of up to:

A

250 psi (1 724 kPa).

63
Q

The tank fill line:

A

allows the tank to be filled without making any additional connections when the pump is being supplied from an external supply source.

64
Q

Valves control most of the ___ lines from the pump.

A

intake and discharge

65
Q

Valves must be:

A

airtight.

66
Q

Which types of valves permit full flow through the lines with a minimum of friction loss?

A

Ball-type valves

67
Q

Which types of valves display readouts of how far the valve is opened?

A

Hydraulically, pneumatically, or electrically controlled valves

68
Q

Which types of valves are most commonly used on large-diameter intakes and discharges?

A

Gate or butterfly valves

69
Q

Gate valves are most often operated by:

A

a handwheel.

70
Q

Butterfly valves are most often operated by:

A

quarter-turn handles.

71
Q

Which types of valves indicate on the panel which direction to operate the switch in order to open or close the valve?

A

Hydraulically, pneumatically, or electrically controlled valves

72
Q

Automatic pressure control devices must operate within ___ seconds after the discharge pressure rises.

A

3 to 10

73
Q

Automatic pressure control devices must not allow the pressure to exceed ___ psi (kPa) above the set level.

A

30 psi (200 kPa)

74
Q

Which types of automatic pressure control devices are sensitive to pressure change and have the ability to relieve excessive pressure within the pump discharge?

A

Discharge pressure relief valves

75
Q

Which types of automatic pressure control devices regulate pressure on centrifugal pumps?

A

Pressure governors

76
Q

Which types of automatic pressure control devices are intended to reduce the possibility of damage to the pump and discharge hoselines caused by water hammer?

A

Intake pressure relief valves

77
Q

Which types of automatic pressure control devices are quick to react to overpressure conditions, but are somewhat slower to reset back to “all-closed” positions?

A

Discharge pressure relief valves

78
Q

Which types of automatic pressure control devices fit onto the carburetor or throttle link and reduces or increases the engine speed under the control of a rod connected to a piston in a water chamber?

A

Piston assembly governors

79
Q

Which types of automatic pressure control devices may be attached to either a regular or an auxiliary throttle?

A

Pressure governors

80
Q

Which types of automatic pressure control devices take a short time for the pump to return to normal operation?

A

Discharge pressure relief valves

81
Q

Which types of automatic pressure control devices should be set to open when the intake pressure rises more than 10 psi (70 kPa) above the desired operating pressure?

A

Intake pressure relief valves

82
Q

Which types of automatic pressure control devices use a pressure-sensing element connected to the discharge manifold to control the action of an electronic pump amplifier that compares pump pressure to an electrical reference point?

A

Electronic governors

83
Q

Which types of automatic pressure control devices relieve excess pressure that is generally caused by shutting down one or more operating hoselines?

A

Pressure governors

84
Q

Which types of automatic pressure control devices have an adjustable spring-loaded pilot valve that actuates the relief valve to bypass water from the discharge to the intake chamber of the pump?

A

Discharge pressure relief valves