Chapter 9 Flashcards
Modern fire department pumpers are equipped with ________________ as
their main pump.
centrifugal pumps
types of positive pressure pumps
piston pump, Rotary gear pump, rotary vane
Positive-displacement pump using one or more reciprocating pistons to force water from the pump chambers.+
Piston pump
Rotary pumps like rotary gear or rotary vane are confined to the uses of___________.
small capacity, booster-type pumps; low volume, high-pressure pumps; and priming pumps.
____________ consist of two gears that rotate in a tightly meshed pat-tern inside a watertight case.
Rotary Gear Pump
This is one of the most common types of pumps used to prime a centrifugal fire pump.
rotary vane pump
A rotor with attached vanes is mounted off-center inside the pump housing; pressure is imparted on the water as the space between the rotor and the pump housing wall decreases.
rotary vane pump
____________ are prone to failure if not exercised regularly. These pumps should be operated during routine apparatus checks.
rotary pumps
Nearly all modern fire apparatus feature a ________________ as their main pump.
centrifugal pump
Pump with one or more impellers that rotate and utilize centrifugal force to move the water. Most modern fire pumps are of this type.
centrifugal pump
Vaned, circulating member of the centrifugal pump that transmits motion to the water.
Impeller
intake orifice at the center of a centrifugal pump impeller.
Impeller eye
Spiral, divergent chamber of a centrifugal pump in which the velocity energy given to water by the impeller blades is converted into pressure.
Volute
What is the simplest form of all fire apparatus pumps?
rotary pumps
How does a priming device get water into a centrifugal pump?
) removing air
The total amount of water that can be pumped by a rotary gear pump depends on:
the size of the pockets in the gears and the speed of rotations
Centrifugal pumps are classified as
non positive displacement pumps
Centrifugal pumps impart:
velocity to the water and converts it to pressure within the pump itself.
Which of the following pumps is the most efficient at pumping air?
) rotary vane pumps
What part of the pump dictates the amount of pressure that is developed?
) the speed of the impeller
Rear engine PTO designs are driven from
the engines flywheel
If there is any question as to the correct position for the transfer valve, it is best to operate in the
parallel position rather than the series position which allows the pump to pump at
100% of its rated capacity at 10 feet of vertical lift and 20 feet of suction hosing
Most fire departments operate pumpers that feature a pump that is mounted:
) laterally across the frame
Midship mount pumps operate by shifting the collar inside the gear box so that power can be diverted
) from the rear axel and transmitted to the fire pump
When the engine is at idle and the pump is engaged, the speedometer will indicate:
) 10-15 mph change
When using a static water source, prime the pump by removing all the air from the pump which
lowers the atmospheric pressure within the pump casing
When each of the impellers takes water from a source and delivers it to the discharge, you are
operating the transfer valve in what position?
parallel
When all of the water from the intake manifold is directed into the eye of the first imepeller, you
would have the transfer valve in what position?
Series
What valves are essential to the operation of a multi-stage pump?
Transfer valve
Due to its self adjusting feature, rotary _____ pumps are more efficient at pumping air than rotary
_______.
vane; gear
What form of energy is transmitted to the water by the impeller?
Pressure
The engine’s piping typically tapers to a square shape in order to eliminate what?
Vortex
What feature is designed to regulate the engine speed to match the pump discharge requirements?
Pressure Governor
The pressure control device must restrict the pressure from exceeding what PSI above the set level?
The electronic governor returns the engine to idle when the intake pressure drops below what PSI?
30
Any device, usually a positive-displacement pump, used to exhaust the air from inside a centrifugal pump and the attached hard suction; this creates a partial vacuum, allowing atmospheric pressure to force water from a static source through the suction hose into the centrifugal pump.
Priming device
Primers fall into several categories
Positive Displacement Primers,Oil-Less Primers,Exhaust Primers,Vacuum Primers,Air Primers
Physical law stating that when a fluid, such as water or air, is forced under pressure through a restricted orifice, there is an increase in the velocity of the fluid passing through the orifice and a corresponding decrease in the pressure exerted against the sides of the constriction.
Venturi effect
Two Types of Auxiliary Cooling Devices
The marine cooler,immersion type auxiliary cooler
