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Firefighter Training > Pumps and Ladders > Flashcards

Pumps and Ladders Flashcards

1
Q

What knots would you use to tie onto a hose length before hauling aloft?

A

Rolling hitch and clove hitch

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2
Q

What could cause an unexpected increase in pressure in the pump?

A

An abrupt change in flow velocity. E.g. turning/opening valves too quickly

Kink in hose
Stone that passed through strainer and blocking the branch
Vehicle parked on hose
Closing a branch

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3
Q

What are the reasons a pump could fail to prime?

A

1) The lift is too great
2) an air leak in the suction side of the pump or in the pump itself

Check suction hose joints, washers and the pump for air leaks and soundness

Start at the source (open water/hydrant) and move back in stages.

Faulty primer

Primer is manual and hasn’t been operated properly

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4
Q

Characteristics of good knots

A

Easy to tie
Easy to untie
Not damage the line
Carry out its intended function safely and without slipping

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5
Q

Describe the gauges on a pump and what you are looking at…

A

High pressure (hose reel pressure. Looking to give branch operators requirement)

Low pressure (hose line pressure; e.g. 70mm. Looking to give the branch operators requirement)

Compound (shows variation in lift. Looking to operate within parameters (8m lift)

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6
Q

What is CREST?

A

C = creating flow, overcoming the inertia of moving water from still to running water. Create the energy for the water to move into the pump
R = raising the level. Takes energy to raise the water from the level of the suction to the base of the pump
E = Entry loss. As water enters the impeller; turbulence and vaporisation of water causes water to be lost
S = Strainers. Holes in a strainer make up the surface area of the diameter of the hose, the energy loss here is from the water moving through silt/stones/dirt in the water and into the strainer
T = temperature. Higher the temp. the closer the water is to it’s boiling point, the water can vaporise and be lost as it’s entering a vacuum where boiling points are lower.
A = Atmospheric pressure. Higher the pressure the more force is pushing down on the water, thus upwards into the pump. A drop in atmospheric pressure therefore requires more energy from the pump

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7
Q

What is the theoretical and practical amount of lift from a pump?

A

10m of lift in theory but due to limiting factors, CREST, this is 8m in practice

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8
Q

what lines are used in the fire service?

A

30m and 15m general purpose (GP) line, both 50mm in circumference.

30m guy line, 40m length,

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9
Q

what is a positive and non positive pump?

A

positive pumps gases and liquids, non positive only pumps liquids

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10
Q

give me 4 examples of positive pumps

A

1) force pumps. Solid piston.
2) lift pumps. like force. But has hollow piston and a valve
3) bucket and plunger. combo of lift and force pump.
4) rotary and semi rotary. Has rotating gear wheel in a cyclinder.

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11
Q

What is an ejector, or jet pump?

A
  • no moving parts
  • jet pump is narrow at throat and widens to decrease pressure. This pressure differential pulls gases and liquids forwards into the vacuum
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12
Q

examples of ejector pumps, jet pumps?

A

exhaust extractor primer

foam inductor

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13
Q

what would cause an unexpected increase in vacuum at the pump?

A
  • compound gauge shows higher negative value
  • blockage in suction stopping water intake, thus increasing vacuum
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14
Q

list the parts of a centrifugal pump:

A
  • strainer
  • pump eye
  • suction cover
  • impeller
  • gauge outlets
  • pump casing/volute
  • delivery outlet
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15
Q

what are the main characteristics of a centrifugal pump?

A
  • at any given speed, when there is no flow the pressure is at a maximum (cannot be increased)
  • pressure decreases as delivery valves are opened and the flow increases
  • when pump speed increases pressure and flow increase
  • when suction lift increases (distance from surface of water to pump head) pressure and flow decrease
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16
Q

what is the difference between flow rate and pressure?

A

flow rate is the pump output
pressure is the resistance imparted to the water.

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17
Q

tell me some considerations you might have when working from open water…

A
  • try and achieve a 3m suction lift
  • position the hard suction in a straight line, then secure in s-bends using a clove hitch, half hitch and tying off with RT&2HH
  • suction strainer submerged to a depth equal to 3 times the diameter of the suction hose, this will prevent a vortex forming which could prevent the pump from priming
  • point the strainer upstream if working in flowing water
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18
Q

Looking at the compound gauge - when working from open water, how do you know there is a fault?

A

a fault will show as either no vacuum reading or a very high vacuum reading

19
Q

When pumping from open water, what are the causes of SUDDEN loss of vacuum?

A

  • strainer not submerged, vortex may be occurring
  • loose coupling or faulty rubber washer
  • pump drain valve is open
  • delivery valve not seating
  • air leak in suction hose
  • leak in gauge pipework
  • defective exhaust valve if an ejector primer
  • no water in water ring primer
  • compound gauge cock closed
20
Q

When pumping from open water, what are the causes of SUDDEN high vacuum reading?

A

  • blocked basket and strainer
  • faulty suction hose or internal lining damage
  • blocked pump eye strainer
21
Q

When pumping from open water, what are the causes of an increased negative compound gauge reading?

A

  • a drop in the level of the supply, e.g. a tidal source
  • a blocked suction stariner
  • a greater pump workload where delivery/flow rate is increased and the pump has to overcome frictional loss to raise the water
22
Q

When pumping from open water, what are the causes of a decreased negative compound gauge reading?

A

  • a rise in the level of the supply, e.g. a tidal source
  • a branch is shut down which reduces the required output and the amount of water being raised
23
Q

How do you prime a pump?

A

Operate the primer device, unless the pump is fitted with a primer which is automatic

24
Q

How do you know the primer is working and you aren’t damaging the pump?

A

lift must be achieved within 45 seconds, if not, either

1) the lift is too great, or,

2) there is an air leak on the suction side of the pump

If priming is unsuccessful then before attempting to prime again check the pump and suction hose joints and washers for air leaks and soundness

25
Q

How can a pump be primed?

A

Pumps can be primed with water using:

1) elevated supply (water forced in by gravity which pushes air out)

2) pressure supply (water forced in by hydrant pressure, air forced out)

3) use of a primer (air pumped out, atmospheric pressure on the water surface pushes water into the suction hose and pump eye)

  • positive displacement pumps are self priming because they can move gas and air, thus exhausting the air inside the pump
26
Q

Name some suitable primers

A
  • reciprocating (piston primers)
  • exhaust gas ejector (used with light portable pumps)
  • water ring and rotary (can be manual or automatic)
27
Q

what are ladders used for?

A
  • rescues
  • gaining access to upper floors
  • replacing burnt staircases
  • descending into basements
  • bridging unsafe floors
28
Q

draw and label a ladder

A

parts consist of:

  • strings
  • rounds
  • head
  • heel
  • extending line
  • pawls
  • main ladder
  • extending section
  • head iron
  • plumb
  • plumbing gear
  • extending pulleys
  • heel or jack beam
  • props
29
Q

list the words of command to get a ladder from the engine, pitch a ladder, bring it down and put back on the engine

A

standby to slip
slip
sight the heel
underrun
extend (well, pawls)
head in
head out
extend to lower (well, lower. well, pawls)
underrun (clear behind)
prepare to launch
launch

  • prepare to tilt and tilt, 3/4 round when restricted pitch.
30
Q

what are the two main methods of water relay?

A

1) to utilise a number of water tenders or carriers to shuttle the supply

2) to relay the water over the distance using pumps and hoses

31
Q

how much water does the water carrier pod carry?

A

9000 litres

32
Q

what are the specs of the high volume pump at powey lane?

A
  • 3km hose
  • 150mm diameter
  • 7000lpm
33
Q

explain a closed water relay

A

water being delivered via hose directly into an appliance which then feeds the next

34
Q

explain an open water relay

A

water being delivered via hose into improvised dams adjacent to each appliance, with the base pump setting into an open water supply

35
Q

what are the general distances between pumps on a water relay?

A

as a rule of thumb - up to 9 lengths between pumps but only up to 7 lengths between the base pump and the first boost pump, because the base pump is working hard to lift the water from the open water source

36
Q

how could you reduce frictional loss on a closed water relay?

A
  • use largest diameter hose
  • twin the feed to reduce the frictional loss to a quarter that of a single hose (but make sure get single feed working first!)
37
Q

when operating the pump how do you calculate the frictional loss to ensure you’re giving the branch operator the pressure they’ve asked for?

A

you simply add up all the pieces of equipment and add that to the bars of pressure requested:

add…

0.1 for each piece of connecting kit e.g. controlling divider

0.2 for each length of 70mm hose

0.4 for each length of 45mm hose

0.1 for each metre of height gained

So 3 lengths of 70mm hose, with a controlling branch divider and the branch working at 5m height means add 1.2

So if asked for 3 bars run the pump at 4.2 bars

38
Q

how do you calculate water required based on the flow rates of hoses?

A

as a rule of thumb approx

300 litres/min for 45mm hose
600 litres/min for 70mm hose

39
Q

it is proposed to use 6 jets attached to 45mm hose, and 4 jets attached to 70mm hose. How much water will be required?

A

6 x 300 litres/min = 1800
4 x 600 litres/min = 2400

= 4200 litres/min

40
Q

what is the nominal working pressure of hose?

A

7 bar

41
Q

what is the optimum pressure for most pumps?

A

7 bar

42
Q

how long does the tank water supply last if running one hose reel? how about two hose reels? now two hose reels and a 70mm main jet?

A

1800L lasts …

12 mins for one hose reel at 150L/min

6 mins for two hose reels at 150L/min each

2 mins for two hose reels (150L/min each) and one 70mm main jet (600L/min)

approx 30 secs for two hose reels (150L/min each) and all four main deliveries open (~600L/min)

43
Q

describe priming the main pump using the LPP

A

set main pump into open water to seal system. Connect LPP to main pump and operate manual primer

44
Q
A

Firefighter Training (9 decks)

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