Pump Theory Review

1
Pump Theory Review

• Section 701

2
Definitions

• Static Pressure is stored potential energy
  available to force water through, pipe, fittings,
  fire hose and adapters. Static means at rest or
  without motion.
• Normal Operating Pressure is that pressure
  found in a water distribution system during
  normal consumption demands.

3
Definitions

• Residual Pressure is that part of the total
  available pressure not used to overcome friction
  loss or gravity while forcing water through
  pipe, fittings, fire hose adapters. Residual
  means a remainder or that which is left.
• Flow pressure is that forward velocity pressure
  at a discharge opening while water is flowing.

4
DEFINITIONS

• Negative Pressure pressure below atmospheric
  (measured in inches of mercury)

5
Definitions

• Atmospheric Pressure is greatest at low
  altitudes and least at very high altitudes. At
  sea level, the atmosphere exerts a pressure of
  14.7 psi (101kPa) which is considered standard
  atmospheric pressure

6
Definitions

• Head Pressure in the fire service refers to the
  height of a water supply above the discharge
  orifice. 1 ft 0.434 or 5 psi per 12 ft. (figure
  6.20)
• Capacity maximum ability of a pump or a water
  distribution system to deliver water

7
Definitions

• Displacement volume or weight of a fluid
  displaced by a floating body of equal weight.
  Amount of water forced into the pump thus
  displacing air.
• Flow motion characteristic of water. Measured
  in gallons per minute (gpm) which is the unit of
  volume measured in the U.S. fire service for
  water movement

8
Definitions

• Friction Loss loss of pressure created by the
  turbulence of water moving against the interior
  walls of the hose or pipe.
• Velocity (quantity) and length affect friction
  loss

9
Definitions

• Hydrant pressure amount of pressure being
  supplied by a hydrant without assistance.

10
Net Pump Discharge Pressure

• actual amount of pressure being produced by the
  pump.
• When taking water from a hydrant, it is the
  difference between the intake pressure and the
  discharge pressure.
• When drafting, it is the sum of the intake
  pressure and the discharge pressure

11
Definitions

• Nozzle reaction the force on the nozzle in the
  opposite direction of water flow.
• Pounds per square inch (psi)- U.S. unit for
  measuring pressure.
• Pump Discharge Pressure actual velocity of the
  water as it leaves the pump and enters the
  hoseline.

12
Definitions

• Vacuum- space completely devoid of matter or
  pressure. In fire service terms, pressure less
  than atmospheric pressure.
• Velocity speed the rate of motion in a given
  direction. Measures in feet per second (fps)
  miles per hour (mph)

13
Definitions

• Water Hammer force created by the rapid
  deceleration of water. Results from closing a
  valve or nozzle to quickly.

14
Types of Pumps

• Positive Displacement Pump
• Piston
• Rotary

15
Types of Pumps

• Centrifugal Pump ( non positive displacement)
• Single stage
• Two stage

16
Positive Displacement Pumps

• Works on the following principle When pressure
  is applied to a confined liquid, the same outward
  pressure is transmitted within the liquid,
  outward and equally in all directions.
• This pump can pump air, and is often used as
  priming pumps for centrifugal pumps
• Two types Piston Rotary

17
Piston Pumps

• Contain a piston that moves back and forth inside
  a cylinder. The pressure developed by this action
  causes intake and discharge valves to operate
  automatically and provides for the movement of
  water through the pump
• Refer to page 205, figures 10.3 -10.6 in your book

18
Piston Pumps

• Single action piston pump on discharge water on
  the down stroke or discharge side.
• Double action piston pump both receives and
  discharges water on each stroke of the piston

19
Rotary Pumps

• Rotary Gear (pg 207, Figure 10.8)
• Rotary Vane (pg 207, Figure 10.9)

20
Rotary Pumps

• Rotary gear consists of two gears that rotate in
  a tightly meshed pattern inside a watertight
  case.
• This forces water and air out the discharge
  chamber as each gear tooth passes

21
Rotary Vane Pumps

• Is constructed with moveable elements that
  automatically compensate for wear and maintain a
  tighter fit with closer clearances as the pump is
  used.

22
Centrifugal Pumps

• All modern fire apparatus utilize the centrifugal
  pump as their major pump. Is classified as a
  non-positive displacement pump, because it does
  not pump a definite amount of water with each
  revolution.
• The more speed equals the more water and/or
  pressure. This is the preferred pump in the fire
  service.

23
Pumps

• Theory 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 edge of the disk

24
Centrifugal pump

• Impeller transmits energy in the form of velocity
  to the water.
• Casing collects the water and confines it in
  order to convert the velocity to pressure. The
  casing directs the water to the discharge of the
  pump.

25
Centrifugal pump

• Eye the impeller rotates very rapidly inside
  the casing generally 200 to 4000 rpm. Water is
  introduced from the intake into the eye of the
  impeller. (figure 10.12)
• The volume capacity is dependent on the size of
  the eye. The larger the eye the greater the flow
  capacity.

26
Centrifugal Pump Parts
Discharge Volute
Impeller Vanes
Shroud Hub
Casing Eye
STRIPPING EDGE (figure 10.11, pg 208)
27
Water flow Centrifugal Pump

• Refer to page 209, Figure 10.13

28
Single Stage Centrifugal Pump

• Are commonly used in the fire service, have a
  single impeller. Figure 10.15
• Front mount pumps, PTO, separate engine driven
  and mid-ship transfer pumps are single intake
  impeller and a simple casing provide capacities
  up to 2000 gpm.

29
Single Stage Midship Pump
30
Two Stage Centrifugal Pump

• Has two impellers mounted within a single
  housing. Are usually mounted on a straight shaft
  driven by a single drive train.
• Figure 10.17

31
Two Stage Impellers
32
Two Stage Impellers
33
Eye Vanes
34
Eye Vanes
35
TWO STAGE MIDSHIP
36
Pumping in Volume(Parallel) Position

• When the pump is in the volume position each
  impeller takes water from a source and delivers
  it to the discharge.
• Each impeller is capable of delivering its rated
  capacity while flowing 50 of the rated capacity.
• If the pump is rated 1000 gpm _at_ 150 psi then each
  impeller supplies 500 gpm to the pump discharge
  manifold. This is total amount of water that can
  be delivered and is the sum of the stages.

37
Pumping in Volume(Parallel) Position

• Refer to page 211, figures 10.18, 10.19. Youll
  need to know the route of water in the volume
  position
• The operator must remember that the pump receives
  its maximum flow rating at 150 psi. Increasing
  the discharge pressure or the pump above this
  figure results in decreased volume of water being
  discharged

38
Pumping in the Pressure (Series) Position

• When the transfer valve is in the pressure
  position, all the water from the intake manifold
  is directed into the eye of the first impeller.
  This water is then sent to the second impeller
  increases the pressure and delivers the water at
  the higher pressure in the pump discharge port.

39
Pumping in the Pressure (Series) Position

• Refer to pages 212 214, figures 10.21, 10.22
  10.23

40
Pump Change Over Volume/Pressure

• For lower rpm, higher pressures, better flows
• Do not operate change over valve above 50 psi net
  pump pressure
• Operate in volume/capacity when using half the
  large discharges or pumping half the rated
  capacity of the pump

41
Change Over Valve
42
Automatic Pressure Control Devices

• Relief valves
• Two basic concepts for pressure relief valves
  those that relieve excess pressure on the
  discharge side of the pump and those that relieve
  excess pressure on the intake side of the pump.

43
Relief Valve System
44
Relief Valve
45
Relief Valve
46
Relief Valves

• The main feature is its sensitivity to pressure
  change and its ability to relieve excess pressure
  within the pump discharge.
• There are many types of relief valves available.
  The most common types use a spring controlled
  pilot valve.
• Read pages 228-230 to understand the operations
  of a relief valve.

47
Pressure Governor

• Pressure can also be regulated on a centrifugal
  pump by a mechanical or electronic governor that
  is pressure activated to adjust the engine
  throttle.
• Its main feature is it regulates the power output
  of the engine to match the pump discharge
  requirements.
• Read pages 230 - 233

48
Pressure Relief Devices

• At a minimum operate once a week
• Operate when one or more large lines are in use
• They do not compensate fore pressure loss

49
Causes of Excessive PressuresIn Fire Hose

• Water Hammer
• Excessive Pump Pressure
• Operator Error

50
Priming Systems

• Are used to create pressures lower than
  atmospheric. Atmospheric pressure then pushes
  water into the pump to fill the void and equalize
  pressures
• Types Gear, Vacuum, Exhaust

51
Priming Systems
52
Priming System
53
Primer Pump Assembly
54
Priming Systems

• Read pages 233 -235
• Figures 10.66 through 10.69

55
Pump Capacity

• When performing a capacity test, the first test
  should be the 100 capacity test.
• Rated capacity
• 100 at 150 psi ___ rpm
• 75 at 200 psi ____ rpm
• 50 at 250 psi ___ rpm

56
Pump Capacity

• Hale Qmax 1500 gpm pump
• Rated capacity
• (100) 1500 gpm _at_ 150 psi, at 1545 rpm
• ( 75 ) 1051 gpm _at_ 200 psi, at 1671 rpm
• ( 50) 750 gpm _at_ 250 psi, at 1851 rpm

57
Pump Capacity

• American LaFrance Two Stage 1500 GPM
• 1500 gpm _at_ 150 psi, at 2017 rpm
• 1050 gpm _at_ 200 psi, at 2138 rpm
• 750 gpm _at_ 250 psi, at 1816

58
Pump Capacity

• Hale QSG 1250 gpm single stage pump
• 1250 gpm _at_ 150 psi, 1594 rpm
• 882 gpm _at_ 200 psi, 1723 rpm
• 625 gpm _at_ 250 psi, 1857 rpm

59
Pump Capacity
60
Conditions That Cause Pump Damage

• Cavitation a condition in which vapor cavities
  are formed in the pump as a result of a pressure
  drop within the pump below the vapor pressure
  based on the temperature of the liquid causing
  vibrations and possible damage to the pump.
• Cause include running away fro water trying to
  pump more water that is available (coming in).
  Churning water no flow or recirculating water

61
Conditions That Cause Pump Damage

• Water Hammer - a shock transmitted to a pump and
  parts when a discharge or nozzle is closed
  rapidly, resulting from the fact water is not
  compressible.
• Pump Overheating damage caused to the pump when
  it is run for prolonged periods with no water
  circulating. Corrected by opening the
  recirculation valve or slightly opening the tank
  fill to allow water to circulate.

62
Auxiliary Cooling Systems

• Marine
• Immersion
• Radiator fill Valve
• Used to control the temperature of coolant in the
  apparatus engine during pumping operations

63
Marine Cooling System

• Is inserted into one of the hoses used in the
  engine cooling system sop that the engine coolant
  will travel through it as it circulates through
  the system.
• Pg 239 read, figure 10.83

64
Immersion Cooling System

• Mounted in a similar manner than the marine
  system, with the radiator coolant passing through
  the body of the cooler. Water from the pump
  passes through coils or tubing mounted inside the
  cooler so that is immersed in the coolant. The
  cooler water from the pump passes through the
  tubing, heat is absorbed from the coolant is
  absorbed by the tubing and dissipated in the
  water from the pump.
• Pg 240, figure 10.84

65
Radiator Fill Valve

• Some manufacturers also supply a radiator fill
  valve. This valve can be used to refill the
  radiator if the coolant level drops too low for
  effective cooling during a pumping operation.
• Should only be used in an emergency.

66
Cooling Valves
67
Supply Hose

• Hard Suction
• Soft Sleeve

68
Hard Suction

• Also known as Hard intake hose
• Non-collapsible hose that connects a pump to a
  source of water that will be used for drafting
• Constructed of reinforced material designed to
  withstand a vacuum

69
Hard Suction
70
Soft Suction Hose

• Also known as soft sleeve hose
• Large diameter
• Collapsible pieces of intake hose are used to
  connect to a fire pump then to a pressurized
  water source.

71
Soft Suction
72
Fire Hose Nozzles

• Solid
• Fog
• Broken

73
Solid Stream Nozzle

• Is a fire stream produced from a fixed orifice,
  smoothbore nozzle.
• Designed to produce a stream as compact as
  possible with little shower or spray.
• Solid streams as handlines should be operated at
  50 psi.
• Solid stream master stream device should be
  operated at 80 psi.

74
Solid Stream Nozzle
75
Solid Stream NozzleDetermination of Flow

• It may be necessary to calculate the flow of a
  solid stream nozzle to determine the amount of
  water that is being discharged.
• Formula GPM 29.7 x d² x vNP
• GPM discharge in gpm
• 29.7 a constant
• d diameter of the orifice in inches
• NP nozzle pressure in psi

76
Solid Stream NozzleDetermination of Flow

• Determine the flow from a 1 inch tip operating at
  50 psi.
• GPM 29.7 x 1² x v50
• GPM 29.7 x 1 x 7.07
• GPM 210

77
Straight Bore Handlines
Size PSI GPM
1 50 210
1 1/8 (1.125) 50 265
1 ¼ (1.25) 50 325
78
Straight Bore Master Streams
Size PSI GPM
1 ¼ 80 400
1 ½ (1.5) 80 600
1 3/4 (1.75) 80 800
2 80 1000
79
Fog Stream Nozzles

• Water stream of finely divided particles used for
  fire control.
• A wide angle deflection produces wide angle fog,
  a narrow angled deflection produces a narrow
  angle fog
• The reach on the fog stream is dependant on the
  width of the stream

80
Fog Stream Nozzles
81
Fog Stream Principles

• PERIPHERY the line bounding a rounded surface,
  the outward boundary of an object distinguished
  from its internal regions.
• DEFLECTION a turning or state of being turned,
  a turning from a straight line or given course, a
  bending or deviation
• IMPINGE to strike or dash about or against,
  clashing with a sharp collision, to come together
  with force.

82
Constant Flow Nozzles

• Constant flow nozzles are designed to flow a
  specific amount of water at a specific nozzle
  discharge pressure on all stream patterns.
• Discharge the same amount of water regardless of
  the stream pattern

83
Fog Nozzles

• Operated at a nozzle pressure of 100 psi
• Automatic nozzles are fog stream nozzles that
  automatically corrects itself to provide a good
  stream at the proper nozzle pressure

84
Automatic Fog Stream Nozzle
85
Handline Nozzles

• Are designed to be placed on mobile attack lines
  that can be easily maneuvered by firefighters.
• May be of solid, fog or broken stream type.
• Designed for hoses ¾ to 3
• Generally, 350 gpm is the maximum amount of water
  that can safely flow through a handline nozzle.

86
Master Stream Nozzles

• Is any fire stream that is to large to be
  controlled without mechanical aid.
• Are powerful and generate a considerable amount
  of reaction force.
• Maybe either solid or fog streams

87
Master Stream Nozzles

• Solid master streams are operated at 80 psi
• Fog master streams are operated at 100 psi
• Flows are 350 gpm or greater

88
Master Stream
89
Pump Panel
90
Pump Panel
91
Tank to Pump

• NFPA 1901 states that piping should be sized so
  that pumpers with a capacity of 500 gpm or less
  should be capable of flowing 250 gpm from their
  booster tank.
• Pumpers with capacities gt500 gpm should be able
  to flow at 500 gpm from the booster tank.