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Pump Course > Module 5 - Fire pump theory and construction > Flashcards

Module 5 - Fire pump theory and construction Flashcards

1
Q

METHODS OF ENGINE-TO PUMP POWER TRANSFER

A

Power Take-Off Drives (PTO)

Midship Transfer Drive

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2
Q

Power Take-Off Drives (PTO)

A

Powered by an idle gear in the transmission and is used primarily on the CFD to operate Aerial PTOs or generator PTOs

Transmissions are placed in the neutral position when operating these PTOs

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3
Q

Midship Transfer Drive

A

Used on most CFD apparatus to operate the pumps

This system has the pump connected to the split-shift transfer case located on the driveline between the transmission and rear axle

This system is operated with the transmission in drive

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4
Q

Positive Displacement pumps
- Hydraulic Law

A

When pressure is applied to a confined liquid, the same outward pressure is transmitted within the liquid and equally in all directions

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5
Q

There are two basic types of positive displacement pumps

A

Piston
Rotary

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6
Q

Piston

A

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

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7
Q

Rotary

A

Rotary gear - Pump consist of two gears that rotate in a tightly meshed pattern inside a watertight case

Rotary vane – pumps are constructed with moveable elements that automatically compensate for wear and maintain a tighter fit with closer clearances as the pump is used

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8
Q

Two great advantages that the centrifugal pump has over the positive displacement pump is that:

A

They can take advantage of incoming pressure

Little to no harm results from shutting of all discharges for a short time

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9
Q

Three main factors greatly influence a centrifugal fire pumps discharge pressure

A
  1. The amount of water being discharged
  2. The speed at which the impeller is turning
  3. The pressure that the water has when it enters the pump from a pressurized source
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10
Q

The amount of water being discharged

A

The greater the volume of water being flowed, the lower the discharge pressure will be

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11
Q

The speed at which the impeller is turning

A

The greater the speed of the pump, the greater the pressure will be developed

This increased is approx.. equal to the square of the change in impeller speed

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12
Q

The pressure that the water has when it enters the pump from a pressurized source

A

The incoming pressure changes will be reflected in the discharge pressure

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13
Q

PUMP ASSEMBLY

A
  • Waterous CMU20 – 2 stage pump, 2000 GPM or 600psi output
  • 200 CFM encapsulated rotary screw compressor
  • Eclipse compressed air foam system
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14
Q
A
  1. foam manifold
  2. compressor oil filter
  3. air outlet manifold
  4. Y- Strainer
  5. compressor
  6. compressor oil heat exchanger
  7. clutch
  8. water inlet relief valve
  9. pump transmission 10. water inlet butterfly valve
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15
Q

Three parts to the Waterous Pump:

A

Impeller shaft assembly
o 2 piece stainless steel shaft
o Bronze impeller
Pump body assembly
Transmission assembly

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16
Q

Impeller

A

Transmits energy in the form of velocity to the water

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17
Q

Casing

A

Collects the water and confines it to convert the velocity to pressure

It then directs the water to the discharge of the pump

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18
Q

centrifugal pump

A
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19
Q

Bronze Impeller

A
  1. front shroud 4. Eye
  2. exit way 5. Vanes
  3. hub 6. Bore
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20
Q

The impeller is mounted off-center in the casing

A

This creates a water passage that gradually increases in cross-sectional area as it nears the discharge of the pump. This section of the pump is known as the volute

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21
Q

Impeller

A
  1. Vanes
  2. Stripping edge
  3. wear rings
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22
Q

Wear Rings

A

Bronze wear rings are used to restrict the amount of water allowed through

The wear rings are trapped in the pump body

The hub of the impeller fits inside the wear ring

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23
Q

Overheat Protection Manager (OPM)

A

Acts as a safety device by releasing hot water to the ground from the discharge side of the pump

The valve itself is capable of resetting after the temperature drops below 104 degrees Fahrenheit at pressures greater than the truck can produce

Will alarm and the red light will illuminate once the water temperature in the pump body reaches a predetermined temperature of 180 degrees Fahrenheit

The system will then automatically begin dump water out of the pump body at 140 degrees Fahrenheit

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24
Q

Electronic Transfer Valve Actuator

A

Should remain in volume position

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25
Q

Electronic Transfer Valve Actuator – The following criteria dictates when the valve should be moved

A

When flowing over 2/3 the capacity of the pump (over 4667 L/Min) have the valve in volume position

When flowing over 1400 kPa have the valve in the pressure position
oT
e valve may be operated at pressures up to 1700kPa without damage to the pump

do not switch from volume to pressure with handlines flowing

26
Q

There are two pumping positions

A

Volume (parallel)

Pressure (series)

27
Q

Volume (parallel) position

A

Each of the impeller takes water from a source and delivers it to the discharge

Each of the impellers is capable of delivering its rated pressure while flowing 50% of the rated capacity

28
Q

Pressure (series) Position

A

All the water from the intake manifold is directed into the eye of the first impeller

The first stage increases the pressure and discharges 50-70% of the volume capacity through the transfer valve and into the eye of the second impeller

The second impeller increases the pressure and delivers the water at a higher pressure into the pump discharge port

Pressure mode should be used when operating at a pressure higher than 1400 kPa

Transfer valves are capable of operating at 1700kPa however best practice is to set the PSG to idle prior to operating the transfer valve

29
Q

Clapper Valves

A

Are essential in a two-stage pump

If they should stick open or closed or get debris caught in them, the pump will not operate properly in the pressure (series) position

30
Q

Cavitation

A

Water is being discharged from the pump faster then it is coming in

Occurs when air cavities are created in the pump or bubbles pass through the pump

Maintain 150kPa on the compound gauge when operating from a pressure fed supply will prevent cavitation

31
Q

Overheating

A

Can be caused by the pump being run for extended periods of time with little or no water flowing

This can be rectified by either opening a dump line, circulating the water through the tank, opening the pump cooler, utilizing the OPM or if there is no water required the pump can be shut down

32
Q

RATED PUMP CAPACITIES

ULC Plate

A

Displays pump performance

As discharge pressure is increased the volume is greatly reduced

1000 kPa is the optimum pump discharge pressure for maximum volume

33
Q

PUMP TRANSFER CASE - Pneumatic shifter

A

Moves back and forth across the 3 gears always in contact with 2 of the 3 gears

Connecting the drive(green) to either the rear driveshaft to the wheels (yellow) or to the pump gear (blue)

34
Q

INTAKE RELIEF VALVE

A

CFD engines are equipped with two inlet relief valves:

o Located on the TFT intake ball valve, set to activate at 1260kPa or less
o Located on the intake side of the main pump casing and set to activate at approx.. 1100kPa

35
Q

PRIMING SYSTEMS

A

Before any centrifugal pump can be operated, it must be primed

Priming is the process of replacing air in the intake lines and portions of the pump with water

If the pump is to be operated from a draft, priming must be done by means of a positive displacement pump

36
Q

Primers fall into two categories:

A
  • Positive displacement primers
    o Used on CFD apparatus
  • Exhaust primers
37
Q

Priming Valve

A

A rubber diaphragm forms a seal that allows the valve to open and close while isolating the interior of the priming valve from atmospheric pressure

The priming valve is attached directly to the highest point on the pump body

Opens automatically during the pump priming

When the valve is open, it allows air to flow from the various pump passages to the priming pump, once the pump is primed, the priming valve closes automatically when the primer is deactivated

38
Q

if the priming pump does not prime the main pump and discharge a steady stream of water within

A

45secs, stop the pump and determine the cause of the problem

39
Q

PUMP CONTROL PANELS

A
40
Q

Drivers side - pump

A
41
Q

front compartment - pump

A
42
Q

officers side - pump

A
43
Q

Electronic Governors - operate in one of two modes

A

Pressure

RPM

44
Q

Pressure

A

Maintains a constant pump discharge pressure, varies the engine speed to maintain the desired pressure

45
Q

RPM

A

Maintains a constant engine RPM (mostly used in drafting or relaying)

46
Q

Ball valves

A

Are used in pumper discharges, the fire piping systems and gated wyes

Are open when the handle is in line with the hose and closed when then handle is at a right angle to the hose

47
Q

Gated valves

A

Used to control the flow from the hydrant

Have a baffle that is moved by a handle and screw arrangement

Have been designed to be fully open or closed

48
Q

Butterfly valve

A

Is a flat baffle operated by a quarter-turn handle

Quick opening valves and are similar in operation to a ball valve, but does not have any pockets in which fluids may become trapped when the valve is closed

49
Q

Clapper valve

A

Used in Siamese appliances, sprinkler and standpipe systems

To allow only one intake hose to be connected and charged before the additional of more hoses

50
Q

Waterous Advantus foam system

A

Engines up to 2017-2018 advantus 3 and all Smeal quints advantus 6

51
Q

Major difference between advantus and Aquis is

A

the Aquis system does not use conductivity probes in the foam manifold, it only uses the flowmeter to calculate how much concentrate to inject into the foam manifold foam

Red is Advantus, Blue is Aquis

52
Q

Applications and advantages of flow meters:

A

Diagnosing water flow problems

Simplify the use of in-line foam educator

Require little maintenance

53
Q

WATEROUS POWER FOAM FILL SYSTEM

A

This system allows pump operators to fill the foam concentrate holding tank, while still standing on the ground

Allowing the pump operator to fill the foam tank while flowing foam at a fire scene

54
Q

FLUSHING SYSTEM

A

After every use, the foam fill system must be flushed

With he wand in clean water and the tank fill/flushing valve in the flush position, depress and hold the manual fill button

55
Q

Drain valves

A

These valves may be used to relieve pressure in the line and make it easier to disconnect the hose, or may be used to belled off air from within the hose line

They should be used in cold weather operations to remove any water out of the pipes to prevent freeze up

56
Q

Gauge Drains

A

Remove water from the gauges to help prevent freeze up

57
Q

Auxiliary coolers

A

Marine and immersion

The primary function is to control the temperature of the coolant in the apparatus engine during pumping operations

58
Q

Auxiliary coolers - Marine

A

inserted in one of the hoses used in the engine colling system in such a way that the engine coolant must travel through it as it circulates through the system

59
Q

Auxiliary coolers - immersion

A

mounted similarly to the marine type, with the radiator coolant passing through a coil or some tubing mounted inside the cooler so that it is immersed in the coolant

60
Q

Strainer screens

A

Designed to stop large foreign bodied objects from entering the pump

Another function is to straighten this stream prior to it entering the pump

Are composed of zinc alloy, and are designed as a sacrificial anode; this helps reduce corrosion in the pump

Pump Course (6 decks)

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