Pump Theory (Week 2) Flashcards
What does the anti siphon hole for a primer pump do?
It allows suction to be relieved when the primer motor is shut-off and prevents oil from being siphoned from the tank when not needed.
The vent hole in a primer tank cap does what?
It allows air into the primer pump tank so oil can flow through to the “PRIMER PUMP” for sealing and lubricating. (Do not confuse the “primer motor” with the primer pump!)
(True/False) Slippage is the ability of H2O to move through the pump “allowing” 100% discharge.
FALSE - Not allowing 100% disharge
A two stage centrifugal pump has…..?
Two impellers on a single shaft and each impeller has its own volute. Each volute discharges into a common outlet. This is all surrounded by the Pump Casing.
When running a fire engine pump and the pump RPM is increased, but there is no increase in pressure, wnat is most likely happening?
Sign of CAVITATION
How do you find your static pressure?
Open hydrant, open tank suction inlet valve, do not open and/or flow any lines and read the compound pressure.
Residual pressure is….?
the pressure remaining in a system while water is flowing
A good working Cal Fire engine can draft _____ to _____ feet?
15’-20’
It is acceptable to crack open your tank fill valve to recirculate water through your pump to prevent overheating. During this procedure you can drop the pressure ____ psi?
10
1 psi of atmospheric pressure will raise water ____feet?
2’
Green hydrant flows…..?
1,000 - 1,499 gpm
Orange hydrant flows….?
500 - 999 gpm
Red hydrant flows…..?
0 - 499 gpm
Blue hydrant flows….?
1,500 - gpm
The impeller shaft, impellers and volutes are housed by the _____?
Pump casing
The ______ valve controls the setting for a pressure relief valve.
Pilot valve (4-way valve)
When pumping in pressure (series), if the first impeller is pumping 150psi to the second impeller what is the total pressure being pumped?
300psi (150+150 = 300psi) pumping in pressure requires the second propeller to double the pressure.
What type of pump is used as a primer pump?
Positive Displacement Pump
What type of pump will pump air?
Positive Displacement Pump
What are three types of positive displacement pumps?
Piston pump, Rotary gear, Rotary vane
When pumping, when do you switch from pressure to volume?
250gpm or half the rated capacity of the pump
When pumping, when do you pump in pressure?
When pumping more than 200 psi
Why do we use a rotary vane pump?
To remove air
The process of removing air from the pump and replacing it with water is known as?
Priming
What type of oil is used in the priming pump?
15-40W
How many shafts are in a multi-stage centrifugal pump?
1
At sea level what is the atmospheric pressure?
14.7 psi
How much psi is lost in every 1000’ elevation increase?
½ psi
For every 1000’ in elevation how much lift is lost?
1 foot
Every mark on the vacuum gauge is equal to how much lift?
1 foot
A compound gauge is capable of reading?
Vacuum and Pressure
A water ejector has a ratio of _ to _ when flowing water?
3 to 1
How far should the drafting hose be under water?
12” to 18” inches
List the parts in the pressure relief valve?
Four way valve, pilot valve, and the relief valve
What is another name for the tank filler valve
Churn Valve (recirculation valve)
How many lines can be added if the difference between static and residual pressure is less than 10%, 15%, 20%
3, 2, 1
What type of pressure gauges are on CDF engines?
Bourdon
What are some common characteristics of a centrifugal pump?
Will pump no air, Needs a primer, Has up to 100% slippage
What are some common characteristics of a positive displacement pump?
Needs no Primer, Pumps air, Has less than 10% slippage
