Chapter 10 Fire Pump Theory Flashcards Preview

IFSTA Pumping Apparatus Driver/Operator > Chapter 10 Fire Pump Theory > Flashcards

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

Positive displacement pumps have largely been replaced by ___ for use as the main fire pump on modern fire apparatus.

Centrifugal pumps

2

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

Priming

3

The two basic types of positive displacement pumps are:

piston and rotary pumps.

4

Piston positive displacement pumps may be:

single-acting or double-acting.

5

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

speed of the piston travel.

6

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

cylinder.

7

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

simplest

8

Rotary positive displacement pumps are now used as:

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

9

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.

pockets in the gears

10

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

wear.

11

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

nonpositive displacement pump

12

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

velocity

13

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

impeller

14

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

casing

15

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

volute

16

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

2,000 to 4,000

17

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.

eye

18

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

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

What is changeover?

The process of switching between the pressure and volume position

20

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.

one-half

21

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.

two-thirds

22

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

50 psi (350 kPa).

23

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).

100%, 150 psi (1 000 kPa)

24

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.

0.01 inch (0.25 mm)

25

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.

clearance

26

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

pump casing.

27

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

graphite or lead.

28

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

packing gland

29

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

Lantern rings

30

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

water

31

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

dry

32

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

mechanical seals

33

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

Freezing

34

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

Auxiliary engine-driven pumps

35

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

Midship pumps

36

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

Front-mount pumps

37

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

Power take-off driven fire pumps

38

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

Midship pumps

39

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

Rear-mount pumps

40

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?

Midship pumps

41

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

Rear-mount pumps

42

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

Auxiliary engine-driven pumps

43

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

Auxiliary engine-driven pumps

44

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

Power take-off driven fire pumps

45

Which pumps are more susceptible to freezing in cold climates?

Front-mount pumps

46

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

Front-mount pumps

47

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

Midship pumps

48

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

Power take-off driven fire pumps

49

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

Auxiliary engine-driven pumps

50

Which pumps offer the maximum amount of flexibility?

Auxiliary engine-driven pumps

51

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

Midship pumps

52

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

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

53

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

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

54

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

500 psi (3 450 kPa)

55

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

intake piping.

56

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.

250 (950 L/min)

57

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.

500 gpm (1 900 L/min)

58

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

4 inches (100 mm)

59

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

1,500 gpm (6 000 L/min)

60

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).

two

61

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

one

62

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

250 psi (1 724 kPa).

63

The tank fill line:

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

64

Valves control most of the ___ lines from the pump.

intake and discharge

65

Valves must be:

airtight.

66

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

Ball-type valves

67

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

Hydraulically, pneumatically, or electrically controlled valves

68

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

Gate or butterfly valves

69

Gate valves are most often operated by:

a handwheel.

70

Butterfly valves are most often operated by:

quarter-turn handles.

71

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

Hydraulically, pneumatically, or electrically controlled valves

72

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

3 to 10

73

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

30 psi (200 kPa)

74

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

Discharge pressure relief valves

75

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

Pressure governors

76

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?

Intake pressure relief valves

77

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?

Discharge pressure relief valves

78

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?

Piston assembly governors

79

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

Pressure governors

80

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

Discharge pressure relief valves

81

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?

Intake pressure relief valves

82

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?

Electronic governors

83

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

Pressure governors

84

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?

Discharge pressure relief valves