ch10 Fire Pump Theory

Question 1

blank pumps are used as priming devices to get water into centrifugal pumps during drafting operations

Answer 1

positivie displacement pumps

Question 2

blank pumps are the simplest of all fire apparatus pumps from the standpoint of design

Answer 2

Rotary-type

Question 3

The blank pump consists of two gears that rotate in a tightly meshed pattern inside a watertight case

Answer 3

Rotary gear pump

Question 4

The blank pump is constructed with movable elements that automatically compensate for wear and maintain a tighter fit with closer clearances as the pump is used

Answer 4

rotary vane pump

Question 5

In this type of pump the rotor is mounted off center inside the housing

Answer 5

Rotary vane pump

Question 6

The blank pump is classified as a nonpositive displacement pump because it does not pump a definitive amount of water with each revolution. Rather it imparts velocity to the water and converts it to pressure within the pump itself

Answer 6

centrifugal pump

Question 7

the operation of a centrifugal pump is based on the principle that?

Answer 7

A rapidly revolving disk tends to throw water introduced at its center toward the outer edge of the disk

Question 8

The blank transmits energy in the form of velocity to the water

Answer 8

impeller

Question 9

the blank collects the water and confines it in order to convert the velocity to pressure

Answer 9

casing

Question 10

the volume capability of the pump is dependent on the size of the blank of the impeller

Answer 10

eye

Question 11

the greater the volume of water being flowed, the blank the discharge pressure

Answer 11

lower

Question 12

doubling the speed of the impeller results in blank times as much pressure if all other factors remain constant

Answer 12

four

Question 13

To minimize the blank thrust of large quantities of water entering the eye of the impeller, a double suction impeller was designed

Answer 13

lateral

Question 14

Water being removed at two places and traveling in opposite directions cancels the blank thrust

Answer 14

radial

Question 15

blank has an impeller for each stage mounted within a single housing

Answer 15

multi-stage centrifugal pump

Question 16

When the transfer valve is in the pressure position, all the water from the intake manifold is directed into the eye of the blank

Answer 16

first impeller

Question 17

the process of switching between pressure and volume is sometimes referred to as

Answer 17

changeover

Question 18

the blank valve are essential in a multi-stage pump

Answer 18

clapper

Question 19

the blank of the water moving through the impeller prevents most water in the discharge from escaping back into the intake

Answer 19

velocity

Question 20

The first indication that wear is becoming a problem is when?

Answer 20

Increased engine RPM is required to pump the rated capacity in pump tests

Question 21

To restore the capacity of the pump without replacing the pump itself, Blank or blank are provided in the pump casing to maintain the desired spacing between the hug of the impeller and the casing

Answer 21

replaceable wear rings, clearance rings

Question 22

the blank transfers the necessary energy to spin the impellers at a very high rate of speed

Answer 22

gearbox

Question 23

Proper mounting of these units is essential for dependable and smooth operation

Answer 23

PTO pumps

Question 24

The PTO unit is powered by an blank in the truck transmission

Answer 24

idler gear

Question 25

The typical unit is driven through a gear box and a clutch connected by a universal joint shaft to the front of the crankshaft

Answer 25

Front-Mount pumps

Question 26

Power is supplied to the pump through the use of a split-shaft gear case(transfer case) located in the drive line between the transmission and the rear axle

Answer 26

Midship pumps

Question 27

These units are driven by a shaft from the front of the vehicle's engine

Answer 27

hydrostatic pumps

Question 28

blank pumps may be powered by either a split shaft transmission or by a PTO

Answer 28

rear mount

Question 29

The majority of all fires are initially fought with the water carried on the fire apparatus blank

Answer 29

tank

Question 30

The blank valve prevent damage to the tank if the tank to pump valve inadvertently opens when water is being supplied to the pump under pressure, such as during a relay

Answer 30

check

Question 31

Pumps that have a capacity of blank gpm or greater may require more than one large intake connection at each location

Answer 31

1,500

Question 32

Discharges to which 1.5, 1.75, and 2 inch handlines are attached must be supplied by atleast blank inch piping

Answer 32

2

Question 33

A tank fill line should also be provided from the blank side of the pump

Answer 33

discharge

Question 34

NFPA 1901 requires some type of pressure control devide to be part of any fire apparatus pumping system. The device must operate within 3 to 10 seconds after the discharge pressure rises and must not allow the pressure to exceed blank psi

Answer 34

30

Question 35

the main feature of a blank is its sensitivity to pressure change and its ability to relieve excessive pressure within the pump discharge

Answer 35

relief valve

Question 36

Blank are intended to reduce the possibility of damage to the pump and discharge hoselines caused by water hammer when valves/nozzles are closed to quickly

Answer 36

intake pressure relief valves

Question 37

it is generally recommended that intake relief valves be set to open when the intake pressure rises more than blank psi above the desired operating pressure

Answer 37

10 psi

Question 38

Most blank are also equipped with a manual shut-off valve that allows the water supply to the pump to be stopped if so desired

Answer 38

Screw on intake pressure relief valves

Question 39

the main feature of a blank is that it regulates the power output of the engine to match pump discharge requirement

Answer 39

pressure governor

Question 40

These use a pressure-sensing element(pressure transducer) that is connected to the discharge manifold

Answer 40

electronic governor