TPC 309 Mech Maint

Question 1

In a pneumatic system, what provides force that performs work?

Answer 1

Compressed air.

Question 2

Work =

Answer 2

Force X Distance

Question 3

If you heat up a gas in a rigid container, you get _________ pressure.

Answer 3

increased

Question 4

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.

Answer 4

greater

less

Question 5

As air flows in a pipe where the diameter decreases, the speed of the air _________ and the pressure _________.

Answer 5

increases

decreases

Question 6

A reciprocating compressor is a:

Answer 6

positive displacement compressor

Question 7

Intake valves are forced open by:

Answer 7

atmospheric pressure

Question 8

The purpose of intercoolers of a two-stage compressor is:

Answer 8

to reduce the power needed to run the compressor

Question 9

Two functions of compressor lubricating oil is to:

Answer 9

reduce friction

cooling of the compressor

Question 10

Unloader valves:

Answer 10

run without delivering air

Question 11

Single state compressors are capable of delivering:

Answer 11

50 psi discharge pressure

Question 12

rotary screw compressors operate at speeds from

Answer 12

3000 - 12,000 rpm

Question 13

The impeller compressor delivers air of:

Answer 13

high volume and low pressure

Question 14

A disadvantage of a centrifugal compressor is:

Answer 14

it requires more power

Question 15

A method of decreasing output of a centrifugal compressor is _____ _________, but this will not work if the reduction is too _____.

Answer 15

speed variation

large

Question 16

Water collects in a pneumatic system because when air decreases, _______ ________ decreases.

Answer 16

moisture capacity

Question 17

To remove water from compressed air:

Answer 17

cool the air

Question 18

After coolers is used with water cooling for ______ compressors that operate more than ___ hours a day.

Answer 18

larger

ten

Question 19

Desiccant removes water form air by:

Answer 19

absorbtion

Question 20

the air receiver’s main purpose is to:

Answer 20

maintain pressure during peak demand

Question 21

Inertial separators depend on:

Answer 21

rapid change in direction of air flow

Question 22

The smallest particle is:

Answer 22

aerosols

Question 23

If a filter that stops 100% of a given particle size, this size is the:

Answer 23

absolute rating

Question 24

Wetted filters can be:

Answer 24

cleaned many times

Question 25

Fine lubricators are used if air flow is:

Answer 25

intermittent and the distance to the equipment is long

Question 26

Laminar flow becomes turbulent when there are:

Answer 26

contractions in the pipe

Question 27

The greater pressure losses occur because airflow at ___ pressure is affected by _______ ________.

Answer 27

low

greater friction

Question 28

When piping is installed as compressor discharge and distribution lines, horizontal pipes should be sloping:

Answer 28

downward about 1 inch for ever 10 feet of pipe

Question 29

When should you be using a pipe joint compound in connection with NPT threaded pipe?

Answer 29

always

Question 30

When disconnecting high pressure lines, be careful of:

Answer 30

blowing of dust or chips

Question 31

Four-way valves have four:

Answer 31

connecting ports

Question 32

A needle valve is an excellent 2-way valve for ____ pressure devices or as a throttling device and causes ____ pressure losses

Answer 32

high

high

Question 33

The spool valve controls flow of air by _______ from one position to another and is ____ to move.

Answer 33

sliding

easy

Question 34

four-way valves are used to:

Answer 34

simplify controls

Question 35

A valve with five connecting ports, two of which are exhaust ports is a:

Answer 35

four-way valve

Question 36

Pressure relief valves:

Answer 36

protect the system from damage

Question 37

Cracking pressure(pressure which valve opens) is determined by:

Answer 37

spring adjustment

Question 38

A diaphragm relief valve responds to quick pressure changes because it works on a:

Answer 38

larger pressure sensitive area

Question 39

Increased pressure on the secondary side of a pressure regulating valve ________ ______ the valve.

Answer 39

slightly closes

Question 40

To guard against excessive pressure on the secondary side of a pressure regulator is to use a:

Answer 40

regulator with a built-in relief valve

Question 41

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

Answer 41

greater

Question 42

Internal springs are used to return a piston in a ______-acting, ______-rod pneumatic cylinder

Answer 42

single

single

Question 43

The main purpose of an exhaust-flow control metering valve is to:

Answer 43

limit return stroke speed

Question 44

Cylinders free to pivot are called:

Answer 44

trunnions or clevises

Question 45

Determines whether control valve can deliver air rapidly enough for a cylinder by calculating the:

Answer 45

capacity coefficient

Question 46

The highest torque a pneumatic motor can exert on a load is:

Answer 46

stalling torque

Question 47

Horsepower output varies tie the _____ and ______ of the shaft

Answer 47

speed

torque

Question 48

Highest power of output of a pneumatic motor occurs at:

Answer 48

medium speed

Question 49

Axial-piston motor transmits force from the piston to the output shaft by:

Answer 49

cam plates and gears

Question 50

Air pressure of 100 psi can create hydraulic pressure of 1,000 if the air piston drives a:

Answer 50

smaller diameter piston