Pumps and Hydraulics

Question 1

Hydraulics

Answer 1

The study of physical characteristics exhibited by fluids at rest and in motion.

Question 2

Hydrostatics

Answer 2

Fluids at rest

Question 3

Hydrokinetics

Answer 3

Fluids in motion

Question 4

Friction Loss

Answer 4

That part of the total pressure that is lost while forcing water through pipes, fittings, hose and adaptors

Question 5

Engine Pressure

Answer 5

Pressure that must be developed at the apparatus to overcome friction loss, elevation, and provide correct nozzle pressure

Question 6

Net Engine Pressure

Answer 6

Engine pressure less any intake pressure

Question 7

Nozzle pressure

Answer 7

Pressure that must be delivered to the nozzle in order for the nozzle to function properly and flow the correct amount of water.

Question 8

Water Hammer

Answer 8

Force transmitted through a fluid when an obstruction is placed quickly in the path flow

Question 9

Cavitation

Answer 9

Bubbles of vapor created in the pump that pass from negative to positive pressure then collapse or implode.

Question 10

Physical characteristics of water

Answer 10

a. 1 gallon of fresh water weighs 8.35lbs
b. 1 gallon of water = 231 cubic inches
c. 1 cuft = 1728 cuin of water
d. 1 cuft = 7.418 gal
e. 1 cuft = 62.5lbs

Question 11

NFPA 1901

Answer 11

Standard on Fire pumps

Question 12

Class A pumpers

Answer 12

c. Pumpers will have one 2.5in outlet for every 250GPM (i.e., TFD engines have 5)
d. UL test plate on pump panel has rated capacities of pump
e. TFD’s pumper’s capacity is 1250
f. Used to boost pressure

Question 13

Rated capacity of TFD pumpers

Answer 13

i. TFD engines rated capacity is 1250GPM
ii. 100% of rated capacity @ 150psi
iii. 70% of rated capacity @ 200psi

Question 14

Five times pumps are tested

Answer 14

a. By manufacturer
b. By 3rd party representative (UL or FM)((Underwriters Laboratory or Factory Mutual))
c. Upon delivery (acceptance test)
d. Annually (done by field units)
e. After extensive maintenance (to pump)

Question 15

Types of pumps

Answer 15

Positive displacement (can move air)
Non-positive displacement
(cannot move air)

Question 16

Positive displacement pumps

Answer 16

i. Pump and displace air
ii. Moves a given amount of water with each stroke or rotation
iii. Two types
1. Piston – works with vacuum created by a moving piston, as well as with one way valves that restrict water flow
2. Rotary – comes in two types
a. Rotary gear
b. Rotary vane

Question 17

Non-positive displacement pumps

Answer 17

i. Centrifugal pumps
ii. Based on the principle of centrifugal force
iii. Most common type used in fire service
iv. Does not pump a definite amount of water with each revolution
v. Capable of utilizing incoming pressure

Question 18

Components of a centrifugal pump

Answer 18

1. Casing
   a. Constructed of fine grain alloy, cast iron
   b. Minimum tensile strength of 30,000psi
   c. Split into two sections for easy removal of impeller assembly
2. Impeller
   a. High quality bronze construction
   b. Stainless steel shaft
   c. Eye at the center with vanes curving outward
   d. Vanes covered on both sides by shrouds, which confine the water within the vane pockets.

Question 19

Part of a centrifugal pump to know for diagram…

Answer 19

i. Eye
ii. Hub
iii. Stripping edge
iv. Volute
v. Impeller
vi. Vanes
vii. Shroud
viii. Casing
ix. Discharge

Question 20

Pump mounting and drive arrangements

Answer 20

a. Auxiliary engine driven (brush truck)
b. Cross mounted engine
c. Power take off (pump and roll)
i. Pump is driven by a crankshaft connected to the PTO on the chassis transmission
ii. Pump pressure changes when the driver changes vehicle speed
iii. Allows pump-and-roll capability
d. Front mount
e. Mid-ship mount (TFD)

Question 21

Stages of pump

Answer 21

a. Refers to number of impellers
b. Both single and multistage are common
c. All TFD pumpers are Hale, Single Stage, midship mounted pumps.
d. Ladder 1 and Tower/Ladder 17 (Quint17) are Waterous, 2 stage pumps

Question 22

2 stage pumping patters

Answer 22

volume/parallel

pressure/series

Question 23

Volume/parallel

Answer 23

i. Each impeller receives ½ the intake volume
ii. Both impellers pump to discharge side of pump
iii. Each impeller is capable of delivering 50% of total capacity
iv. Total GPM equal to the sum of each impeller
v. Transfer valve between impellers closed
vi. Used when you want more than 50% of rated capacity

Question 24

Pressure/series

Answer 24

i. Water is pumped from first impeller through open transfer valve to second impeller then to discharge
ii. Pump discharge volume remains constant
iii. Second stage impeller doubles pressure
iv. Used when less than 50% of rated capacity is needed
v. Engine doesn’t have to work as hard

Question 25

Pump accessories

Answer 25

``` Relief valves and governors Priming devices Discharge and intake valves Instrumentation gauges Auxiliary coolers ```

Question 26

Standard relief valves

Answer 26

a. Relieves excess discharge pressure back into the suction side of the pump 2. Separate intake and discharge relief systems

Question 27

TPM relief system

Answer 27

a. Total Pressure Master b. Relieves excess pressure from both discharge and intake sides of pump c. Has a sensing valve on intake side of pump i. Blinking light = relieving external ii. Solid light = relieving internal d. On all TFD pumpers

Question 28

Pressure governors

Answer 28

a. Use engine speed to control excess discharge pressure b. Engine speed determines impeller speed c. Hydraulic line from discharge side of pump transmits pressure rise to governing device which then cuts back the throttle.

Question 29

What do relief valves and governors do?

Answer 29

a. Use engine speed to control excess discharge pressure b. Engine speed determines impeller speed c. Hydraulic line from discharge side of pump transmits pressure rise to governing device which then cuts back the throttle.

Question 30

Priming devices

Answer 30

i. Necessary because centrifugal pumps are not capable of pumping air ii. Three categories 1. Positive displacement pump a. Rotary vane or rotary gear b. TFD uses rotary vane on all apparatus c. Electric drive 2. Exhaust pumps 3. Vacuum pumps

Question 31

Types of gauges

Answer 31

Pressure | Compound (can read below 0)

Question 32

Controls and instruments at pump panel

Answer 32

1. Master pump intake gauge 2. Master pump pressure gauge 3. Tachometer 4. Engine temp gauge 5. Engine oil pressure gauge 6. Voltmeter 7. Discharge valves 8. Primer control 9. Water tank to pump valve control 10. Water tank fill valve control 11. Water tank level indicator

Question 33

Instrument and gauge details

Answer 33

iii. On both types of gauges, pressure is measure by a gauge containing a closed curved tube known as the Bourdon Tube. iv. As pressure is applied water enters the open end of the tube and it tends to straighten v. The tube is connected to a gear mechanism that controls the movement of the needle. vi. Master pump intake gauge must be compound 1. Reads in psi on pressure side 2. Reads in 0-30 inHg on vacuum side

Question 34

Auxiliary coolers

Answer 34

i. Engine cooler – helps control engine temp during pumping operations. Uses heat exchanger 1. Usually in upper radiator hose 2. New pumpers installed near pump tranny ii. Recirculating line (pump cooler) – Keeps pump water cool when pump is engaged and no water is flowing. Recirculates water from pump to booster tank.

Question 35

Pumping problems

Answer 35

i. Water hammer 1. Force transmitted through a fluid when an obstruction is placed quickly in the path of the flow. 2. Can damage equipment and hurt people. 3. Can be prevented by opening and closing valves on hydrants, trucks and nozzles slowly. ii. Cavitation 1. Bubbles of vapor created in the pump that pass from negative to positive pressure then collapse or implode 2. Sounds like gravel in the pump 3. Damages the pump 4. Caused by running out of water, or water getting too hot.

Question 36

Engine pressure formula

Answer 36

Engine pressure = Nozzle pressure + Friction Loss +/- Hydrant pressure + appliance loss (EP=NP+FL+/-HP+AL)

Question 37

Smooth bore formula

Answer 37

iii. GPM formula 29.7*D^2*√NP | iv. Nozzle reaction = 1.5*D^2*NP

Question 38

Fog nozzle formula

Answer 38

v. Fogs have preset GPM settings/ratings vi. NR=.05*GPM*√NP vii. √50=7.07 ^^not sure what this last bit is..^^

Question 39

Friction loss

Answer 39

1. All based off of 2.5in hose 2. FL/100’ = 2Q^2+Q for over 100GPM 3. FL/100’ = 2Q^2+.5Q for less than 100GPM 4. If you need to change something, do [formula]*coefficient a. 1.75in hose coefficient = 5.95 b. 2.5in hose coefficient = 1 c. 5in hose coefficient = .031 d. Red line coefficient = 86

Question 40

Tandem pumping

Answer 40

i. Two pumpers operating from one hydrant ii. Hooked up inlet to inlet iii. Used when a single hydrant has more water available than is being utilized by a single pumper

Question 41

Relay pumping

Answer 41

i. Used when it is necessary to lay supply lines over long distances ii. Distance limited by friction loss and elevation iii. Pumpers set in relay to boost pressure iv. Attempt to maintain 40lbs residual pressure v. Hooked up outlet to inlet

Question 42

THINGS TO KNOW!!!

Answer 42

a. When to use volume/parallel and pressure/series b. What is NFPA 1901 c. 100% of rated capacity is at 150GPM d. Know the five times the apparatus pump is tested e. Gallon of water – 8.35 f. Main advantage of a centrifugal pump is that it can utilize incoming pressure g. Formulas are based off of 2.5in h. Know the difference between tandem and relay pumping i. Q = quantity of water/100 j. Know the nozzle pressure formulas k. Know friction loss l. Know definitions