The absolute discharge pressure compared to the absolute intake pressure is referred to as
guage pressure
compression ratio
isentropic exponent
isothermal compression
absolute pressure
Air at normal atmospheric conditions located at the compressor inlet is termed
free air
interstage air
compression air
ambient air
unloaded air
The volumetric efficiency of an air compressor is the ratio of
1st stage cylinder volume to 2nd stage cylinder volume
inlet air temperature compared to discharge air temperature
capacity to displaced volume
isothermal compression compared to adiabatic compression
cylinder volume compared to air receiver volume
An air compression curve on a pressure-volume diaphragm will be:
pure polytropic
purely isentropic
purely isothermal
somewhere between constant pressure and constant volume
somewhere between adiabatic and isothermal
The clearance volume on an air compressor
has no effect on discharge capacity
has a direct effect on compressor capacity
varies with the speed of the compressor
must be large enough to prevent the cylinder overheating
is important in the event that there is moisture in the air being compressed
An air compressor at a significantly higher altitude compared to an air compressor at a lower altitude will deliver:
less volume of air
higher volume of air
less mass of air
more mass of air
an equal mass of air
The effect of moisture in a compressed air system is detrimental because:
it will lower the discharge air temperature
it will cause corrosion in the air piping
it will freeze in the winter
it will plug the actuators
it requires more power to compress the air
The term dewpoint is defined as
saturation pressure of the air
the temperature of the air when it begins to absorb moisture
relative humidity
the temperature of the air when water vapour begins to condense
none of the above
Air compressors may be classified as either:
positive displacement and dynamic
single acting and double acting
single stage and multi stage
positive displacement and negative displacement
centrifugal and reciprocating
which type of air compressor is best suited for high pressure, moderate volume applications
reciprocating
centrifugal
rotary
dynamic
axial
A reciprocating air compressor compared to a rotary air compressor is:
more efficient
less efficient
equally efficient
easier to operate
requires less lubrication
which of the following is a positive displacement compressor:
turbine
A reciprocating compressor has the ability to deliver oil-free air if:
no oil is used to lubricate the cylinder
the piston uses Teflon rings
if the exhaust air is filtered prior to entering the air reciever
not possible to deliver oil free air
synthetic oil is used instead of conventional oil
A reciprocating air compressor is suitable for:
pulsation free air
low pressure applications
all pressure ranges
delivering moisture free air
all of the above
The piston on an air compressor may be made of
alloy steel
cast iron
steel
aluminum
A double-acting reciprocating compressor:
has more than one stage
may compress more than one fluid at a time
must utilize an intercooler
receives and discharges air at both ends of the cylinder
is of a dynamic axial design
