TPC 309 Mech Maint Flashcards
In a pneumatic system, what provides force that performs work?
Compressed air.
Work =
Force X Distance
If you heat up a gas in a rigid container, you get _________ pressure.
increased
If two cylinders with a different diameter is connected by an air line, force on the load is _______ than the force applied to the smaller piston. The distance the load moves is ____ than that of the smaller piston.
greater
less
As air flows in a pipe where the diameter decreases, the speed of the air _________ and the pressure _________.
increases
decreases
A reciprocating compressor is a:
positive displacement compressor
Intake valves are forced open by:
atmospheric pressure
The purpose of intercoolers of a two-stage compressor is:
to reduce the power needed to run the compressor
Two functions of compressor lubricating oil is to:
reduce friction
cooling of the compressor
Unloader valves:
run without delivering air
Single state compressors are capable of delivering:
50 psi discharge pressure
rotary screw compressors operate at speeds from
3000 - 12,000 rpm
The impeller compressor delivers air of:
high volume and low pressure
A disadvantage of a centrifugal compressor is:
it requires more power
A method of decreasing output of a centrifugal compressor is _____ _________, but this will not work if the reduction is too _____.
speed variation
large
Water collects in a pneumatic system because when air decreases, _______ ________ decreases.
moisture capacity
To remove water from compressed air:
cool the air
After coolers is used with water cooling for ______ compressors that operate more than ___ hours a day.
larger
ten
Desiccant removes water form air by:
absorbtion
the air receiver’s main purpose is to:
maintain pressure during peak demand
Inertial separators depend on:
rapid change in direction of air flow
The smallest particle is:
aerosols
If a filter that stops 100% of a given particle size, this size is the:
absolute rating
Wetted filters can be:
cleaned many times
Fine lubricators are used if air flow is:
intermittent and the distance to the equipment is long
Laminar flow becomes turbulent when there are:
contractions in the pipe
The greater pressure losses occur because airflow at ___ pressure is affected by _______ ________.
low
greater friction
When piping is installed as compressor discharge and distribution lines, horizontal pipes should be sloping:
downward about 1 inch for ever 10 feet of pipe
When should you be using a pipe joint compound in connection with NPT threaded pipe?
always
When disconnecting high pressure lines, be careful of:
blowing of dust or chips
Four-way valves have four:
connecting ports
A needle valve is an excellent 2-way valve for ____ pressure devices or as a throttling device and causes ____ pressure losses
high
high
The spool valve controls flow of air by _______ from one position to another and is ____ to move.
sliding
easy
four-way valves are used to:
simplify controls
A valve with five connecting ports, two of which are exhaust ports is a:
four-way valve
Pressure relief valves:
protect the system from damage
Cracking pressure(pressure which valve opens) is determined by:
spring adjustment
A diaphragm relief valve responds to quick pressure changes because it works on a:
larger pressure sensitive area
Increased pressure on the secondary side of a pressure regulating valve ________ ______ the valve.
slightly closes
To guard against excessive pressure on the secondary side of a pressure regulator is to use a:
regulator with a built-in relief valve
The thrust can be applied when the rod of a single-rod, double acting pneumatic cylinder is moving out of the cylinder is _______ than the thrust that can be applied when the rod is moving into the cylinder
greater
Internal springs are used to return a piston in a ______-acting, ______-rod pneumatic cylinder
single
single
The main purpose of an exhaust-flow control metering valve is to:
limit return stroke speed
Cylinders free to pivot are called:
trunnions or clevises
Determines whether control valve can deliver air rapidly enough for a cylinder by calculating the:
capacity coefficient
The highest torque a pneumatic motor can exert on a load is:
stalling torque
Horsepower output varies tie the _____ and ______ of the shaft
speed
torque
Highest power of output of a pneumatic motor occurs at:
medium speed
Axial-piston motor transmits force from the piston to the output shaft by:
cam plates and gears
Air pressure of 100 psi can create hydraulic pressure of 1,000 if the air piston drives a:
smaller diameter piston
