305 Flashcards
An archimedian screw pumps water by rotating ___ in a ___.
Thread;trough
If a substance needs to remain within a limited range of temperatures as it flows to the point of use, the distribution system may require
Insulated pipes
A centrifugal pump is suitable for pumping waste because of the ___ head requirement and because the pump can move ___
Low; small particles
Pumps for high viscosity materials generally need to be ___pumps
Positive displacement
Which kind of pump is generally used for moving grease, mastic, concrete, and other near the solid materials
Piston
The eye of a pump impeller is above the level of the supply liquid in the ___ condition
Suction lift
Total dynamic head is the sum of the ___ the ___ and the ___
Static head; head loss; velocity head
The horsepower input to a pump is called ___ horsepower
Brake
In order to use the performance curve for a centrifugal pump, you must know the pumps ___ and its ___
Speed; impeller diameter
Which pump curve will tell you at what total head the best energy transfer takes place
Efficiency
End suction centrifugal pumps make up about ___% of the pumps used in industrial planta
80
In a multistage centrifugal pump each stage increases the ___ of the fluid
Velocity
The open impeller is used mainly for pumping fluids containing ___ solids
Large
In a centrifugal pump wear rings prevent damage to the ___ and ___
Impeller; casing
The purpose of shaft sleeves is to prevent ___ from causing wear on the ___
Packing ; shaft
In a line shaft turbine the ____ surrounds the ____
Bowl; impeller
Diffuser vanes in an axial-flow propeller pump
Straighten the fluid flow
The main difference between an axial flow propeller pump and a mixed flow propeller pump is the shape of the
Impeller
What causes electrochemical corrosion in a pump
Combining incompatible materials
Regenerative turbine pumps can be used only to pump fluids with
Low viscosity
In an external gear pump fluid is carried between the teeth of ___ and the ___
Both gears; pump housing
In an external gear pump, fluid is carried between the teeth of ___ and the ___
Both gears, crescent
Lobe pumps are similar to ____ pumps in their construction and operation
External-gear
In a screw pump, fluid moves because of the
Progressive cavities between threads
The diameter of the impeller if a vane pump is ___ the diameter of the housing. The centerline of the impeller is ___ the centerline of the housing
Smaller than; offset from
The piston that pumps fluid in a direct acting reciprocating pump is commonly driven by an
Air
Single acting reciprocating pumps discharge fluid on the ___ stroke
Forward only
The piston that pumps the fluid in a power reciprocating pump is commonly driven by
Electric motor
Most metering pumps are
Reciprocating
Most metering pumps are lubricated by the
Fluids they pump
The force that moves the diaphragm in most diaphragm pumps is provided by the
Hydraulic fluid
What actuates the valves of diaphragm pumps
Fluids being pumped
Rotary pumps used for metering are usually ___ pumps
Vane
In a flexibl-tube pump, the ___ forces the fluid out the discharge port
Roller
The problem of leakage in a pump used for moving liquid chemicals is eliminated by the ___ pump
Magnetic -drive
A dry type dump pump retains its prime, because the
Suction intake is above the impeller
The ___ and the ___ of a reciprocating slurry pump require the most maintenance
Cylinder sleeves, valve seats
The advantage of a vortex pump is that the
Fluid makes little contact with the impeller
A little leakage through the packing on a pump is usually ___ because it ___
Desirable, lubricates the shaft
Pumps designed for use under suction lift conditions require
Injection type stuffing box
Pumps that operate at temperatures over 450F are usually usually packed with
Aluminum
When preparing to install new packing in a pump, your first step should be to
Shut off and lock out the power
Why forks the seal in a packingless seal
Boller condensate
Overfilling the oil reservoirs on a pump can result in
Overheating bearings
Grease used for lubricating the bearings of pumps should be free of
Mineral fillers
If a pumps bearing seals need frequent replacement, the problem may be caused by a
Rough shaft
The major maintenance problem in rotary pumps are usually confined to the
Bearings and seals
If a reciprocating pump loses its ability to provide enough pressure, the problem may be ___ but you should check the ___ before replacing them.
Worn piston rings, internal check valves
Compared to a piston, the plunger of a power pump is typically ___ and has a ___ stroke
Longer ; longer
An air driven reciprocating pump can deliver fluid at a pressure higher that the supplied air pressure if the fluid piston is __ the air piston
Smaller in diameter than
