Pneumatics, Vacuum, heat exchangers dryer test

Question 1

warmer the air the more moisture it can hold

true

False

Answer 1

True

Question 2

relative humidity compares the amount of water a sample of air holds to the maximum amount it could hold if fully saturated

true

False

Answer 2

True

Question 3

if a cubic foot of air has the capacity to hold 11 grains of moisture but has 5 grains of moisture, then it is said to have _______________ % relative humidity

50

45

40

35

Answer 3

45

Question 4

if the air is cooled past 100 % relative humidty, then condensation will result. this is called the_________

dry air point

specific humidity point

vapour point

dew point

Answer 4

Dew point

Question 5

water / moisture in a compressed air system needs to be separated and removed by

air receivers

after coolers

dryers

all the above

Answer 5

All of the above

Question 6

adsorption dryers work on the principle of ________ of molecules in a thin layer onto the desiccant

a chemical bond

vapourization

adheasion

regeneration

Answer 6

Adhesion

Question 7

the process of removing the accumulation of moisture from the dryer bed is called____________ which uses ________________

regeneration, heat

regeneration, absoption

regeneration, purge gas

both the 1st and 3rd answer are correct

Answer 7

Both first and third

Question 8

about __________% of dry air is used for regeneration in heater-less dryers

10-15

20-30

40-60

1-2

Answer 8

10-15

Question 9

the ideal system for adsobtion dryers is a twin tower system with ___________ which reduces the amount of cycle times and compressed air usage

cams and mechanical valves

electronic switches and automatic valves activated by the dew point sensor in the system

electronic switches and automatic valves

none of the above

Answer 9

Electric switches and automatic valves activate by the dewpoint sensor in the system

Question 10

because desiccant can break down of become contaminated with oil, the air drying system needs to be protected with coalescing filters

true

False

Answer 10

True

Question 11

in the regeneration cycle, the purge air is _____________ to help reduce compaction and make removal of moisture faster

sped up

deflected

reversed

cooled

Answer 11

Reversed

Question 12

.a heated adsorption dryer with internal heaters uses about______% of the dryed air.

2

5

10

12

Answer 12

2

Question 13

the moist gas from the regeneration cycle (purge gas) in not explosive or hazardous, then it can be vented to the atmosphere. otherwise it has to be cooled and ran thru a moisture separator and re-introduced to the dryer inlet gas stream

true

false

Answer 13

True

Question 14

the rotary drum dryer has 2 separate air flows going thru it. the hot dry gas passes thru____ % of the rotor and the moist gas passes thru ______ % of the rotor

50, 50

75, 25

25, 75

60, 40

Answer 14

25,75

Question 15

absorption dryers use __________ in the process to dry the air

adheasion

vaporization

chemical bond

all the above

Answer 15

Chemical bond

Question 16

chemical dryers cannot be regenerated because they dissolve or melt when combined with moisture

true

false

Answer 16

True

Question 17

in the liquid dehydration process, an absorption agent such as ethylene glycol is sprayed thru nozzles and as the air travels down thru it, it is scrubbed and moisture absorbed

true

False

Answer 17

False

Question 18

to remove the moisture from the glycol, it is ran thru a ______________where it is heated to 200 C and moisture is evaporated

heat exchanger

vapourizer

steam cleaner

still

Answer 18

Still

Question 19

refrigeration dryers use the dew point reduction method to remove moisture from the air thru the use of an air circuit and a refrigeration cycle

true

False

Answer 19

True

Question 20

latent heat is heat that is sensed by a thermometer

true

False

Answer 20

False

Question 21

in mechanical dryers, water sprayers are added to cool down the air before it strikes the baffles that create a torturous path

true

false

Answer 21

False

Question 22

colescing filter elements can effectively remove particles down to a size of _________ microns

0.001

0.0001

0.01

0.1

Answer 22

.01

Question 23

the best way to determine if a dryer is taking out moisture, is to

check the dessicant

watch the cycle times

measure the flow rates

measure the dew point of the air

Answer 23

Measure the dew point

Question 24

wire drawing is

used to seal flanges

process of air movement thru the dessicant

a fine groove cut in a sealing surface (caused by high pressure gas)

none of the above

Answer 24

A fine groove cut in a sealing surface (caused by high pressure gas)

Question 25

most dryers that run below 175 degrees C, use a teflon valve seat true False

Answer 25

True

Question 26

in a pneumatic system, the compressor intake should be in a __________ place because the air is denser wet cool hot

Answer 26

Cool

Question 27

when compressing with a reciprocating compressor, you need a _____________ to help dampen pulsations after-cooler minimum of bends in the intake inter-cooler receiver

Answer 27

Receiver

Question 28

the pneumantic piping system that has the compressor close to its point of use is the grid decentralized loop none of the above

Answer 28

Decentralized

Question 29

proper sizing of lines in a pneumatic system is important because if the piping is to small, it will cause moisture in the air supply cool the air supply cause a pressure drop in the air supply create more flow

Answer 29

Cause a pressure drop in the air supply

Question 30

you must eliminate all leaks in a compressed air system because it will cost more to produce the needed CFM true False

Answer 30

True

Question 31

if an FRL is installed backwards, it would gum up the regulator with oil remove lubrication work normally the 1st and 2nd answers are correct

Answer 31

Both first and second answers

Question 32

in an FRL, the filter uses ___________ and the lubricator uses ________ to work properly centrifugal force, venturi venturi, centrifugal force none of the above regeneration, desiccant

Answer 32

Centrifugal force, venturi

Question 33

water traps use a _________ to expel moisture automatically from the unit pressure drop deflector plate float valve hand valve

Answer 33

Float valve

Question 34

a 5/3 valve has ________ and ____________ positions 3 ways, 5 5 ways, 3 5 ports, 3 both the 2nd and 3rd answers are correct

Answer 34

Both second and third answers are correct

Question 35

a pressure reducing valve has a normally _____________flow path thru it closed open both open and closed none of the above

Answer 35

Open

Question 36

venting regulators will protect the _______________ from over pressure upstream section downstream section does not protect any part of the system vent to the receiver

Answer 36

Downstream section

Question 37

a DCV is identified by of controlled connections of switching positions method of activation all the above

Answer 37

All of the above

Question 38

external and internal pilot operation, are valves activated manually by air electrically all the above

Answer 38

by air

Question 39

you would use a 4/2 valve to activate a single acting cylinder double acting cylinder a center position in the valve all the above

Answer 39

Double acting Cylinder

Question 40

you would use a 5/3 valve to control as cylinder with the valves center position control a single acting cylinder control a rotary motor with the valves center position both the 1st and 3rd answers are correct

Answer 40

Both first and Third Answers are correct

Question 41

the needle valve is the most accurate flow control valve for metering flow true False

Answer 41

True

Question 42

a quick exhaust valve is used to expel gas at the directional control valve cylinder receiver compressor

Answer 42

Cylinder

Question 43

excess flow valves are used on air hoses that are larger than 1/2", to eliminate hose whipping true False

Answer 43

True

Question 44

double acting cylinders use _____________ to slow down the piston at the end of each stroke packing o-rings stop tubes cushions

Answer 44

Cusions

Question 45

when using flow controls to slow down the movement of a cylinder in an circuit, you would _________ the air with the flow control meter-in meter-out

Answer 45

Meter out

Question 46

air logic applications are used in systems that have an explosive environment a very wet environment air gauging all the above

Answer 46

All of the above

Question 47

which rotary motor uses a swash plate to control speed of actuation vane piston turbine gear

Answer 47

Piston

Question 48

you have a cylinder that is sticking when extending and retracting. what may the problem be rod packing to tight pilot pressure is to low to shift spool valve all the way a bent piston rod all the above

Answer 48

All of the above

Question 49

when reassembling and installing parts, you should aways check the component for proper operation true false

Answer 49

True

Question 50

if you have a system that you want to protect an operator from getting their hands caught in an unsafe area, you would have a system that would require the operator to hold both hands on 2 different levers that needs both levers moved at the same time to operate the equipment true false

Answer 50

True

Question 51

when thawing a frozen valve, make sure to apply heat as quick as possible to limit the possibility of a fire true false

Answer 51

False

Question 52

if you have excessive pressure in part of a pneumatic system, you will look for a flow restriction leak in the system pressure regulator set to high pressure regulator set to low

Answer 52

Pressure regulator set to high

Question 53

if you have a cylinder moving inconsistently, you will look for bent piston rod damaged piston seals inconsistent air pressure all the above

Answer 53

All of the above

Question 54

if a cylinder body seal is leaking, you will look for loose cylinder tie rods true false

Answer 54

true

Question 55

a pneumatic valve is blowing to exhaust when actuated. what is the problem valve seals are leaking spool damage valve to base gasket is faulty all the above

Answer 55

All of the above

Question 56

a poppet is chattering in a pneumatic system. the problem is most likely the air supply pressure is too low the pilot pressure is too low air supply pressure is too high both the first and second answers are correct

Answer 56

Both first and second answers are correct

Question 57

the actuator cylinder is drifting in a pneumatic system. The problem could be a piston seal is leaking true false

Answer 57

True

Question 58

vacuum systems are limited to ________ of vacuum pressure to work with 14.7 psi 29.92 'Hg 29.92 psi 14. Kpa

Answer 58

14.7PSI

Question 59

plumbing size for pipe in a vacuum system must be as small and short as pradtical for static systems true False

Answer 59

True

Question 60

if your vacuum system has back pressure, this will cause the system to be more efficient true False

Answer 60

Flase

Question 61

when hooking up a vacuum system to a cylinder, you would hook the vacuum up to the _________ port to make it extend rod end cap end it works the same way as a pressure system none of the above

Answer 61

Rod end

Question 62

if you had an air valve that you are going to use as a vacuum valve, you would hook up the pressure port to atmosphere and the exhaust port to the vacuum source true false

Answer 62

True

Question 63

.you would use a vacuum relief valve for static systems. this would allow the pump to be cooled and lubricated. the system would also use less horsepower true false

Answer 63

True

Question 64

when lifting and holding with suction cups in a vacuum system, you would calculate the area under the cup and times it by the number if inches of Hg (mercury) to find the weight the cup could hold true False

Answer 64

False

Question 65

you want to use _________ seals on your cylinder's piston for vacuum systems as they produce the least amount of friction metal O-ring leather cup none of the above

Answer 65

Leather cup

Question 66

you can use some vacuum systems in combination (as a vacuum system and as a pressure system). the system will produce high pressures ( 100 psi) on the exhuast side of the pump true False

Answer 66

False

Question 67

if you had a 3" suction cup that has a vacuum of 20" Hg pulling on it, how much could you lift? f = p x a 2' Hg = 1 psi 31 lbs 51 lbs 61 lbs 71 lbs

Answer 67

71LBS

Question 68

when replacing gaskets in vacuum pumps, it is important to have the proper thickness for proper sealing inside the pump true false

Answer 68

True

Question 69

heat exchangers have the ability to cool or heat the air and or liquid to a constant temperature true False

Answer 69

True

Question 70

heat exchangers have 3 basic means of heat transfer at work. they are conduction, covection and radiation. the one the uses CONTACT between the fluid and metal surface is conduction convection radiation

Answer 70

Conduction

Question 71

the rate of heat transfer is influenced by the amount of direct scrubbing action that is present in the fluid flow. this scrubbing action is caused by laminar flow forced convection turbulent flow forced flow

Answer 71

Turbulant flow

Question 72

there are many different flow path arrangements. the one that is the most efficient at cooling is the parallel flow counter flow cross flow mixed flow

Answer 72

Counter flow

Question 73

in plate heat exchangers. it is important to have the spacing of the plates close together. they should be spaced at _______________ apart 6 to 10 mm 11-15 mm 16-20 mm 2-5 mm

Answer 73

2-5mm

Question 74

spiral heat exchangers are very efficient because they have a true counter flow and create their owm scrubbing action true False

Answer 74

True

Question 75

cooling towers can be divided into 2 classes. they are forced draft and induced draft true False

Answer 75

False

Question 76

forced draft is when the air flow is pulled out of the cooling tower true False

Answer 76

False

Question 77

double pipe heat exchagers are able to handle high pressures only handle low heat duties be connected in series or in parallel all the above

Answer 77

All of the above

Question 78

shell and tube heat exchangers have large surface areas for heat transfer the capability of handling only low temperatures and pressures the capacity of handling high temperatures and pressures both the 1st and 3rd answers are correct

Answer 78

Both first and third answers are correct

Question 79

the tubes are commonly expanded into the __________ to form a seal against leakage shell tube sheets baffles head cover

Answer 79

Tube sheets

Question 80

an advantage of the u-tube heat exchanger over the fixed tube heat exchanger is the tubes are cleaned easier the outside of the tubes are cleaned easier because the tubes can be taken out of the shell there are inspection doors that let you access the outside of the tubes it has a higher efficiency

Answer 80

the outside of the tubes are cleaned easier because the tubes can be taken out of the shell

Question 81

the tube sheet layout that allows for the most tubes for a given size exchanger is the 30 degree style 45 degreee style the 90 degree style they all create the same number of tubes

Answer 81

3o degree style

Question 82

baffles in heat exchagers help support the tubes to prvent vibration cause turbulence prevent dead bypass areas all the above

Answer 82

All of the above

Question 83

3 longitudinal baffles will make the heat exchanger a _____________ pass exchanger 1 2 3 4

Answer 83

4

Question 84

floating head shell and tube exchangers will allow 1 tube sheet to float which allows the exchanger to use fluids of an extremely high temperature differential true False

Answer 84

True

Question 85

the only heat exchanger that is used where it is undisireable to allow the mixing of the tube side and shell side fluids in the exchanger is the floating head u-tube fixed tubesheet shell double tube sheet

Answer 85

Double tube sheet

Question 86

heat transfer in a heat exchanger is affected by __________________ fluid flow temerature differentials contact time all the above

Answer 86

All of the above

Question 87

fluid films are formed next to the tube walls. they decrease the heat transfer. to help increase heat transfer thru the tubes you can increase the temperature pressure velocity all the above

Answer 87

Velocity

Question 88

hydrostatic testing is commonly used to check heat exchangers for leaks. the standard pressure used in hydro-testing is the same pressure as the system 1.5 times system pressure 2 times system pressure 3 times system pressure

Answer 88

1.5 times the system pressure

Question 89

when first applying the flows of fluid into the heat exchanger, make sure the _____________valve is opened so all air in the exchanger can be purged out vent shuttle butterfly none of the above

Answer 89

Vent

Question 90

when purging a dryer or heat exchanger system of toxic gases, you would use nitrogen carbon dioxide steam all the above

Answer 90

All of the above