Pneumatics Flashcards
In a pneumatic system, what provides the force that permits work?
Compressed Air
How much work is done by a piston that exerts a force of 15lb through a distance of 10in?
150 in-lb.
W = F x D
Heating a gas in sealed, rigid container will _______ the ________ of the gas.
Increase; pressure
Two cylinders having different diameters are connected by an air line. A force applied to the smaller piston makes it move. In response, the larger piston exerts a force on a load and makes it move. The force on the load is ___________ the force applied to the smaller piston, and the distance the load moves is __________ the distance the smaller piston moves.
Greater than; less than
When air flowing in a pipe reaches a section where the diameter is reduced, the speed of the air _________ and its pressure _________.
Increases; decreases.
A reciprocating compressor is one kind of _________ compressor.
Positive-displacement
In a typical reciprocating compressor, the intake valves are forced open by the….
Atmospheric pressure
The purpose of an inter cooler between the stages of a two-stage compressor is to reduce the:
Power needed to run the compressor.
The purposes of lubricating oil in a compressor are to reduce the friction between the moving parts and to…
Improve the cooling of the compressor
The advantage of unloading a compressor is to allow it to….
Run without delivering air
Single-stage sliding-vane compressors can produce pressures up to ____ psi.
50
Rotary screw compressors run at speeds ranging from _____ to ______ rpm.
3000; 12000
Impeller compressors deliver air at ________ volume and _______ pressure.
High; low
Compared to other kinds of compressors, centrifugal compressors….
Require more power
The most effective method of reducing the output of centrifugal compressors is ________ but my not work well if the reduction is too _____.
Speed Variation; large
Water often collects in a pneumatic system because when air is compressed it’s __________ decreases.
Moisture Capacity
The most common way to remove water vapor from the air leaving a compressor is to
Cool the air
Water cooled after coolers are typically use with ______-capacity compressors that run _____ hours a day.
Large; ten or more
A dessicant removes water from air by _________ it.
Abosorbing
The main purpose of the receiver in a pneumatic system is to…
Maintain pressure during peak demand
The operation of an inertial separator depends on a(n)
Rapid change in the direction of air flow
Of the particles listed below, the smallest are the _________ particles
Aerosol
A filter can stop 100 percent of the particles down to a specified minimum size. This size is called the filter’s __________ rating.
Absolute
An advantage of wetted filters over dry filters is the at wetted filters…
Can be cleaned many times
A fine mist lubricator should be used in a pneumatic system if the air flow is _________ and/or the distance to the equipment is _________.
Intermittent; long
Laminar air flow in a piping system is made turbulent by
Obstructions in the pipe
Greater pressure losses occur in a pneumatic system if the air is at _________ pressure, because of greater _________.
Low; Friction
When used as a compressor discharge line, a pipe run should slope ________ in the direction of the airflow by 1 inch for every _____ feet of pipe
Downward; 10
When should you use pipe joint compound in connecting NPT-threaded pipe?
Always
If an air hose is not completely depressurized when you disconnect it, the greatest danger to you is a sudden…
Blowing of dust chips
A four-way valve has four:
Connection points
The ________ valve is a good throttling device and is suitable for high-pressure service. It causes _____ pressure loss in the line.
Needle; high
The spool in a valve controls the flow of air by _______ from one position to another. In a high-pressure system, the spool is ________ to move.
Sliding; easy
An advantage of four-way valves over two and three way valves is that they
Simplify the controls
A valve has five connecting ports, two of which are exhaust ports. This valve is a ________ valve.
Four-way
The cracking pressure or a poppet-type relief valve is determined by the
Spring Adjustment
A diaphragm-type relief valve responds very quickly to pressure change because of its
Large pressure-sensitive are
The only purpose of a pressure relief valve is to
Protect the system from damage
An increase in pressure on the secondary side of a pressure regulating valve _______ the valve.
Slightly closes
The best way 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 that can be applied when the rod of a single-rod, double acting pneumatic cylinder is moving out of the cylinder is ___________ the thrust that can be applied when the rod is moving into the cylinder.
Greater than
An internal spring is sometimes used in the return of the piston in a ________-acting _______-rod pneumatic cylinder
Single; single
The main purpose of an exhaust flow control metering valve on a pneumatic cylinder is to
Limit the return-stroke speed
A cylinder that must be free to pivot requires a(n) _________ mounting
Trunnion or clevis
You can determine whether a control valve can deliver air rapidly enough for a cylinder by calculating the _____________ required by the valve.
Capacity coefficient
The highest torque a pneumatic motor can exert on a load is it’s _________ torque.
Stalling
The horsepower of a pneumatic motor varies with the ______ and the ______ of the motor shaft.
Speed; torque
The highest power output of a pneumatic motor occurs when its speed is
Medium
An axial-piston pneumatic motor transmits force form the piston to the output shaft by means of a
Cam plate and gears
Air pressure of 100 psi can create hydraulic pressure of 1000psi if an air piston drives a ________ hydraulic piston(s)
Smaller-diameter
