2 AimsTo provide students information about fire service pumps and their operation
3 Learning Outcomes At the end of the session students will be able to: Detail the requirements of a fire service pumpDescribe how a centrifugal pump worksDescribe how a peripheral pump worksDetail the operating principles of an ejector pumpcontinued…
4 Detail the operating principles of priming devices used within the brigade Describe the operating principles of pressure and compound gaugesList the considerations to be taken into account when carrying waterList the considerations to be taken into account when relaying water.
5 Types of pumps POSITIVE - Displace both liquids and gases NON-POSITIVE - Displace only liquids aseparate primer beingrequired to remove the airfrom the system.
6 Requirements of a pump A fire service pump must be; Self-contained Light in weightAble to handle large quantities of waterAble to produce fairly high pressuresReliableEasy to operate and maintain.
12 Characteristics of centrifugal pumps At any given speed where there is no flow pressure is at a maximumPressure decreases as the delivery valves are opened and the flow increasesWhen pump speed increases pressure and flow increaseWhen suction lift increases pressure and flow decrease.
13 Advantages of centrifugal pumps Simple maintenanceCan be run against closed deliveries without damageLight and compact relative to their outputCan be driven directly from an internal combustion engine.
14 Velocity and pressure changes within a centrifugal pump. Suction hoseimpellervolute
15 Increasing pump pressures This can be done in a number of ways;Increasing the size of the impellerIncreasing the speed of the impellerIncreasing the number of impellers (as in a 2-stage or multi-stage pump)Using a peripheral pump.
18 The peripheral pump Advantages; Can produce high pressures at relatively low running speeds,saving on wear & tearCan be mounted on the same shaft as the centrifugal pumpIdeally suited for use with high pressure hose reels.
20 Power take off (PTO)Directs engine power away from the road wheels to drive another piece of equipment, such as the fire pump.
21 Cooling systemsDuring pumping operations some water is taken from the high pressure side of the pump to a heat exchanger where it assists in cooling the engineThe water then flows back to the low pressure side of the pump.
22 Priming There are three ways to prime a centrifugal pump; Use of a gravity fed supplyVia a pressure fed supplyBy using a priming device to remove air from the pump.
23 Function of a primerUsed where a static water supply is lower than the pumpThe primer removes air from the pump and creates a partial vacuum allowing atmospheric pressure to effectively force water up the hard suction into the pump.
24 Water ring primer.Rotating impellerOutletsInlet from pump
25 Water ring primer.Ring of waterOval housingLow pressure
26 Water ring primer. Air rushes in from pump Air is forced out of the primer
27 Operating principle of the ejector pump. Venturi effectSurrounding fluidFluid & propellantThroatJet
28 Hughes-Noble ejector pump. propellantthroat area
44 Negative readingsA negative reading of 0.1bar would indicate a lift from open water of approximately 1metresA reading of 0.4bar would indicate a lift of 3 metres allowing for practical considerations.
45 Water carrying Used where the water requirement is relatively limited When the distances between the water source and fireground may be considerable.
47 Distances between pumps Depends on;The flow requiredPump pressure usedContours of the relay routeSize, type and number of hose linesIf the pump is lifting water as well as delivering.
48 Confirmation Assessments will be based on this lesson and the corresponding study note Learning OutcomesDetail the requirements of a fire service pumpDescribe how a centrifugal pump worksDescribe how a peripheral pump worksDetail the operating principles of an ejector pumpcontinued…
49 Detail the operating principles of priming devices used within the brigade Describe the operating principles of pressure and compound gaugesList the considerations to be taken into account when carrying waterList the considerations to be taken into account when relaying water.