Pump Operator C. 10
Terms
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- Name 2 problems associated with Piston Pumps.
- Pulsating Fire Stream & Susceptible to Wear
- Output capacity of PDP (Rotary Gear) depends on _____ & _____.
- Size of Pockets & Speed of Rotation
- What are the Gears of a PDP (Rotary Gear) made of?
- Soft Metal such as Bronze
- What is the Casing of a PDP (Rotary Gear) made of?
- Strong Alloy such as Cast Iron
- In Volume (Parallel) each impeller delivers its rated pressure while flowing ____ % of its rated capacity.
- 50%
- In Pressure (Series) ____% of volume capacity is discharged into the eye of the second impeller.
- 50%-70%
- What is the maximum discharge pressure allowed when changing over?
- 75%
- What type of valve dictates volume versus pressure?
- Clapper
- What is the first sign of wear between the Hub of Impeller & Casing (Wear Rings)?
- Greater RPM required to pump Rated Capacity.
- Define Latern Ring.
- Spacer between Packing designed to cool & lubricate Packing.
- How many 2 1/2 inch or larger Discharges are required on a Pumper?
- Enough to flow its Rated Capacity
- What is the minimum # of 2 1/2 inch Discharges on a Pumper with a Rated Capacity of 750 GPM or greater?
- At least 2.
- What is the minimum # of 2 1/2 inch Discharges on a Pumper with a Rated Capacity less than 750 GPM?
- 1
- What is the largest Discharge allowed on a Pump Panel?
- 2 1/2 inch
- 1 1/2, 1 3/4, 2 inch Preconnect Discharges must be supplied by at least ____ inch pipe.
- 2 inch
- What type of valve are Discharges usually equipped with?
- Locking Ball Valve
- A Tank less than 1000 Gallons must have a Tank Fill Line at least ____ inches?
- 1 inch
- A 1000 Gallon Tank or greater must have a Tank Fill Line at least ____ inches?
- 2 inches
- Which side of the pump is the Circulator Valve connected to?
- Discharge Side
- What is the most common type of Pump Valve? Why?
- Ball Valve; Permits full flow with minimum Friction Loss
- What is the purpose of Automatic Pressure Regulation?
- Ensure safety of FF operating hoseline.
- ____ actuates the Relief Valve to bypass water from the ____ to the ____.
- Spring Loaded Pilot Valve; Discharge Side; Intake Chamber.
- Define PTO in regards to fire pumps.
- Power Take Off; Pump driven by rotating shaft that transfers power from vehicle's engine.
- Define Priming.
- Removing all or most of the air from pump thus lowering Atmospheric Pressue within the Pump Casing.
- What are the 2 general categories of Fire Pumps?
- Positve Displacement & Centrifugal
- Explain the Positive Displacement Pump.
- Self priming pump that moves a given amount of water through the pump chamber with each stroke; All water & air is forced out of pump with each operating cycle; Used to prime Centrifugal Pump
- Explain the Centrifugal Pump.
- Pump with one or more Impellers that utilized centrifugal force to provide discharge pressure; Take advantage of Incoming Pressure
- What are 2 types of Positive Displacement Pumps?
- Piston & Rotary
- The Volume Capability of Centrifugal Pump depends on ___.
- Size of the Eye
- What are the 2 main parts of a Centrifugal Pump?
- Impeller & Casing
- Define Impeller.
- Vaned, circulating part of Centrifugal Pump that transmits motion (velocity) to water.
- Define Casing.
- Collects & confines water to convert velocity to pressure.
- Define Volute.
- Spiral, divergent chamber of Centrifugal Pump in which velocity from the Impeller is converted to pressure.
- As the Volute nears the Discharge Side its size ___.
- Increases
- What are the 3 main factors influencing Centrifugal Pump Discharge Pressure?
- 1. Amount of water being discharged; 2. Speed of Impeller; 3. Intake Pressure
- What are the 2 basic types of Centrifugal Pumps?
- Single Stage (1 Impeller) & Dual Stage (2 Impellers)
- What is the benefit of a Double Suction Impeller?
- Takes in water from both sides to minimize Lateral Thrust.
- At what PSI does the pump receive Maximum Flow Rating?
- 150 PSI
- What are Packing Rings used for?
- Maintain semi-tight seal where the shaft passes through Pump Casing.
- What are Packing Rings made of?
- Rope Fibers impregnated with Graphite or Lead
- What are 2 types of Ball Valve Actuators?
- T-Handles & Quarter Turn
- At what RPM does a Centrifugal Pump rotate?
- 2000 - 4000 RPM
- How many times faster does the Impeller turn than the Engine?
- 1.5 - 2.5
- What are 3 categories of Primers?
- Positive Displacement; Exhaust; Vacuum
- Describe a T-Handle Actuator.
- Pulls straight out & locks via 90 degree twist; Sliding gear tooth rack engages gear on valve stem.
- What are the advantages of T-Handles?
- Provide Mechanical Advantage; Easy to operate under pressure; Allow more precise setting.
- Within how many seconds must a Pressure Control Device activate?
- 3 - 10 seconds
- How many PSI above a discharge setting must a Pressure Control Device activate?
- At least 30 PSI
- What are the 2 main functions of a Relief Valve?
- Be sensitive to pressure changes & be able to relieve excessive pressure within the Pump Discharge.
- How does a Pressure Governor work?
- Regulates power output of engine to match Pump Discharge requirments; Engine Speed dictates Impeller Speed & Impeller Speed dictates Pressure
- What are 2 advantages of an Electric Primer versus a Mechanical Primer?
- Operates regardless of engine speed & allow maximum flexibility in mounting.
- What are 2 purposes of Primer Oil?
- Seals gap between Gears & Casing as pump wears (provding better efficeincy) & Protects metal from corosion.
- What is the purpose of the vent in the Oil/Fluid Line?
- Prevents Oil/Fluid from being siphoned out of tank after Primer use.
- What results if Packing is too tight?
- Water will not flow between Packing & Shaft causing heat to build up.
- What results if Packing is too loose?
- Excessive leak of air & water will affect pumps ability to draft.
- When does Packing actually receive water for lubrication?
- When the pump is full & operating under pressure
- What are 2 types of Pump Drive Systems?
- Auxillary Engine Driven & Power Take Off
- What are 3 types of Pump mounting arrangements?
- Front Mount; Midship Transfer; Rear Mount
- Define Auxillary Engine Drive Pump.
- Pump powered by engine independent of vehicle's engine.
- What is the benefit of an Auxillary Engine Drive Pump?
- Capable of Pump & Roll
- Where is a Midship Transfer Drive Pump mounted?
- Laterally across frame behind engine
- How is the Midship Transfer Drive Pump powered?
- Powered by split shaft gear (Transfer Case) in drive line between transmission & rear axle; Driven by series of gears or drive chain.
- What 2 things limit the Maximum Capacity of Midship Transfer Drive Pumps?
- Engine Horsepower & Size of Pump
- What are 4 types of Midship Transfer Case controls?
- Mechanical; Electrical; Hydraulic; Pneumatic
- What are the 4 primary components of Pump Piping System?
- Intake Piping; Discharge Piping; Pump Drains; Valves
- During Hydrostatic Testing, how many PSI must the pump & piping system be able to withstand
- 500 PSI
- How many GPM must a pumper with a capacity of 500 GPM or less be capable of flowing from the tank?
- 250 GPM
- How many GPM must a pumper with a capacity of more than 500 GPM be capable of flowing from the tank?
- 500 GPM
- What prevents damage to the tank if the Tank-to-Pump Valve is open when water is being supplied under pressure?
- Check Valves
- Where is the Primer tapped into the Pump?
- At the high point on the Intake Side of Impeller Eye
- Where are Intake lines tapped into Pump? Which Intake line is an exception?
- Below the Impeller Eye; Tank-to-Pump Line which provides water under natural pressure of gravity.
- Why does Intake Piping taper to a square as it nears the pump?
- To eliminate vortex that could allow air to enter the pump.
- What 2 things determine the amount of flow that can be obtained through Intake piping?
- Diameter of pipe from valve to pump inlet & Straightness of pipe routing.