Pneumatics

Question 1

In a pneumatic system, what provides the force that permits work?

Answer 1

Compressed Air

Question 2

How much work is done by a piston that exerts a force of 15lb through a distance of 10in?

Answer 2

150 in-lb.
W = F x D

Question 3

Heating a gas in sealed, rigid container will _______ the ________ of the gas.

Answer 3

Increase; pressure

Question 4

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.

Answer 4

Greater than; less than

Question 5

When air flowing in a pipe reaches a section where the diameter is reduced, the speed of the air _________ and its pressure _________.

Answer 5

Increases; decreases.

Question 6

A reciprocating compressor is one kind of _________ compressor.

Answer 6

Positive-displacement

Question 7

In a typical reciprocating compressor, the intake valves are forced open by the….

Answer 7

Atmospheric pressure

Question 8

The purpose of an inter cooler between the stages of a two-stage compressor is to reduce the:

Answer 8

Power needed to run the compressor.

Question 9

The purposes of lubricating oil in a compressor are to reduce the friction between the moving parts and to…

Answer 9

Improve the cooling of the compressor

Question 10

The advantage of unloading a compressor is to allow it to….

Answer 10

Run without delivering air

Question 11

Single-stage sliding-vane compressors can produce pressures up to ____ psi.

Answer 11

50

Question 12

Rotary screw compressors run at speeds ranging from _____ to ______ rpm.

Answer 12

3000; 12000

Question 13

Impeller compressors deliver air at ________ volume and _______ pressure.

Answer 13

High; low

Question 14

Compared to other kinds of compressors, centrifugal compressors….

Answer 14

Require more power

Question 15

The most effective method of reducing the output of centrifugal compressors is ________ but my not work well if the reduction is too _____.

Answer 15

Speed Variation; large

Question 16

Water often collects in a pneumatic system because when air is compressed it’s __________ decreases.

Answer 16

Moisture Capacity

Question 17

The most common way to remove water vapor from the air leaving a compressor is to

Answer 17

Cool the air

Question 18

Water cooled after coolers are typically use with ______-capacity compressors that run _____ hours a day.

Answer 18

Large; ten or more

Question 19

A dessicant removes water from air by _________ it.

Answer 19

Abosorbing

Question 20

The main purpose of the receiver in a pneumatic system is to…

Answer 20

Maintain pressure during peak demand

Question 21

The operation of an inertial separator depends on a(n)

Answer 21

Rapid change in the direction of air flow

Question 22

Of the particles listed below, the smallest are the _________ particles

Answer 22

Aerosol

Question 23

A filter can stop 100 percent of the particles down to a specified minimum size. This size is called the filter’s __________ rating.

Answer 23

Absolute

Question 24

An advantage of wetted filters over dry filters is the at wetted filters…

Answer 24

Can be cleaned many times

Question 25

A fine mist lubricator should be used in a pneumatic system if the air flow is _________ and/or the distance to the equipment is _________.

Answer 25

Intermittent; long

Question 26

Laminar air flow in a piping system is made turbulent by

Answer 26

Obstructions in the pipe

Question 27

Greater pressure losses occur in a pneumatic system if the air is at _________ pressure, because of greater _________.

Answer 27

Low; Friction

Question 28

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

Answer 28

Downward; 10

Question 29

When should you use pipe joint compound in connecting NPT-threaded pipe?

Answer 29

Always

Question 30

If an air hose is not completely depressurized when you disconnect it, the greatest danger to you is a sudden…

Answer 30

Blowing of dust chips

Question 31

A four-way valve has four:

Answer 31

Connection points

Question 32

The ________ valve is a good throttling device and is suitable for high-pressure service. It causes _____ pressure loss in the line.

Answer 32

Needle; high

Question 33

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.

Answer 33

Sliding; easy

Question 34

An advantage of four-way valves over two and three way valves is that they

Answer 34

Simplify the controls

Question 35

A valve has five connecting ports, two of which are exhaust ports. This valve is a ________ valve.

Answer 35

Four-way

Question 36

The cracking pressure or a poppet-type relief valve is determined by the

Answer 36

Spring Adjustment

Question 37

A diaphragm-type relief valve responds very quickly to pressure change because of its

Answer 37

Large pressure-sensitive are

Question 38

The only purpose of a pressure relief valve is to

Answer 38

Protect the system from damage

Question 39

An increase in pressure on the secondary side of a pressure regulating valve _______ the valve.

Answer 39

Slightly closes

Question 40

The best way to guard against excessive pressure on the secondary side of a pressure regulator is to

Answer 40

Use a regulator with a built in relief valve

Question 41

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.

Answer 41

Greater than

Question 42

An internal spring is sometimes used in the return of the piston in a ________-acting _______-rod pneumatic cylinder

Answer 42

Single; single

Question 43

The main purpose of an exhaust flow control metering valve on a pneumatic cylinder is to

Answer 43

Limit the return-stroke speed

Question 44

A cylinder that must be free to pivot requires a(n) _________ mounting

Answer 44

Trunnion or clevis

Question 45

You can determine whether a control valve can deliver air rapidly enough for a cylinder by calculating the _____________ required by the valve.

Answer 45

Capacity coefficient

Question 46

The highest torque a pneumatic motor can exert on a load is it’s _________ torque.

Answer 46

Stalling

Question 47

The horsepower of a pneumatic motor varies with the ______ and the ______ of the motor shaft.

Answer 47

Speed; torque

Question 48

The highest power output of a pneumatic motor occurs when its speed is

Answer 48

Medium

Question 49

An axial-piston pneumatic motor transmits force form the piston to the output shaft by means of a

Answer 49

Cam plate and gears

Question 50

Air pressure of 100 psi can create hydraulic pressure of 1000psi if an air piston drives a ________ hydraulic piston(s)

Answer 50

Smaller-diameter