120101h Flashcards
1
Q
Which gas is produced using the air liquefaction process?
A) acetylene
B) oxygen
C) propane
D) hydrogen
A
B) oxygen
2
Q
Explain why oxygen is dangerous
A
It is combustible and may react violently with some materials
3
Q
For efficient heating and cutting operations, oxygen must have a minimum purity of
A) 80%
B) 93%
C) 98.6%
D) 99.5%
A
D) 99.5%
4
Q
Oil or grease in contact with pure oxygen can:
A
React violently and cause an explosion
5
Q
Explain how acetylene gas is produced
A
By mixing calcium carbide and water in an acetylene generator
6
Q
Define acetylene generator
A
A machine used to produce acetylene gas by bringing specific amounts of granulated, calcium carbide, and water together under strictly controlled conditions. the vapours acetylene gas is collected from the generator as it is produced, and it is placed into specifically design cylinders for storage and use
7
Q
A) the critical pressure for acetylene is_______kPa(_______psi)
A
A) 193kPa or 28psi
8
Q
List 4 fuel gases used for heating and cutting
A
Acetylene, propane, natural gas, propylene
9
Q
List two methods used for storing oxygen
A
- As a liquid in a cryogenic container like a thermos bottle
- Stored as a gas in high-pressure cylinders
10
Q
Name the safety device used on oxygen cylinders and what is its bursting pressure?
A
It is a metal rupture disc that has a bursting pressure of about 22,000 kPa or 3200 psi
11
Q
Compare the pressures and contents of a full-size oxygen cylinder with a half size cylinder
A
The pressure is the same for both cylinders, but the volume of the gas in the half side cylinder is half that of the full-size cylinder
12
Q
Explained why fuel gas cylinders have left-hand threads and non-fuel gas cylinders have right hand threads
A
It’s a safety feature that insures the equipment is not interchanged or hooked up incorrectly
13
Q
Explain why an acetylene cylinder is filled with a porous material
A
The porous material prevents a large volume of free acetylene gas from accumulating under high-pressure to keep the acetylene stable
14
Q
State the location and purpose of fusible metal plugs
A
Fusible plugs are located on the top and bottom of acetylene cylinders in case of fire. They melt at approximately 100°C or 212°F, providing a controlled release of gas, which helps to prevent an explosion of the cylinder
15
Q
State two safety precautions used to prevent acetone loss
A
- Keep acetylene cylinders in vertical positions during storage and use.
- Do not exceed the draw limit.
16
Q
What should be done before the cylinder valve protective caps are removed?
A) cylinder should be pressure tested
B) cylinder should be secured
C) cylinder valve should be cracked
D) equipment should be lubricated and ready for installation
A
B) cylinder should be secured
17
Q
In order to protect the regulator gauges from being damaged
A) only use regulators with a preset stage
B) release the adjusting screw before you open the cylinder valve
C) engage the adjusting, screw to allow unrestricted gas flow
D) use only gauges equipped with heavy duty bourdon tubes
A
B) release the adjusting screw before you open the cylinder valve
18
Q
Which type of regulator fitting requires a fibre washer
A
A flat faced fitting found on some acetylene regulator/cylinder valves
19
Q
Why are cylinder valves cracked before the regulators are attached?
A
To remove dust or dirt from the cylinder valve
20
Q
How should you check for leaks on oxy fuel equipment?
A) and open flame
B) a spark lighter
C) spray with anti-spatter solution
D) apply a suitable leak detection fluid
A
D) apply a suitable leak detection fluid
21
Q
When shutting down an oxy fuel outfit you should
A) close the cylinder valves and bleed the system
B) close the valves and bleed the system
C) back off the regulator screws and bleed the system
D) roll up the hoses and remove the welding tip
A
A) close the cylinder valves and bleed the system
22
Q
Regarding shutting down an oxy fuel outfit answer, true, or false to the following
A) hoses are rolled up_______
B) torch valves are closed ________
C) regulator, adjusting screws are disengaged_______
D) cylinder valves are closed_________
E) shut down, is done at the end of each work shift _______
A
All statements are true
23
Q
Why are regulators used for oxy fuel heating, and cutting operations?
A
To maintain a constant working and delivery pressure
24
Q
What precaution should be taken when regulators are to be stored for extended periods of time?
A
Turn in the working pressure, adjusting, screw enough to release the spring pressure on the diaphragm to move the valve off the valve seat
25
List two types of regulators and briefly explain the operation of each type
1. Single stage regulators reduce source pressure to working pressure in one step.
2. Two stage regulators reduce source pressure to working pressure in two steps.
26
What does creep mean as it relates to welding equipment regulators
Creep is a condition where the high-pressure valve is not seated so gas leaks into the low pressure side and causes an uncontrolled pressure rise in the low pressure chamber
27
How would you safely repair an acetylene hose?
Cut out the damaged area and splice using CGA approved fittings of yellow brass, iron or steel
28
What colour is the oxygen hose?
Green
29
Which hose fittings have a left-handed thread?
The fuel gas fittings have a left-handed thread
30
List two tools that may be used to properly clean a dirty tip
1. Tip cleaners.
2. Tip drills.
31
On page 47 of module eight oxy fuel equipment there is a diagram label the diagram
32
On page 48 of module eight oxy fuel equipment label the diagram on question 32
33
What is the difference between a backfire and a flashback?
A backfire occurs in the mixer and tip. A flashback occurs beyond the mixer into the hose and regulator on the low pressure side.
34
List four causes of backfires
1. Two little gas speed.
2. Obstruction of gas flow.
3. Loose or faulty connections between the tip and mixer.
4. A hot tip.
35
List four causes of flashbacks
1. Grossly unequal pressures.
2. Mildly unequal pressures plus an obstruction of the tip.
3. Failing to purge the lines.
4. Faulty manipulation of valves.
36
Describe a burn back
A burnback is combustion that takes place steadily in the tip and mixer of the torch
37
Why do you purge each line individually on an oxy fuel outfit before lighting the torch?
To prevent flashbacks, you purge the lines of any air or explosive mixture that may be present
38
When changing heating tips to a different size why is there a need to rebalance gas pressures?
A) to ensure the tip is free of dirt
B) because the orifice size is different
C) to prevent a burn back
D) to ensure the proper gases are in their respective hoses
B) because the orifice size is different
39
Why should the acetylene torch valve always be set so the flame is above the smoke range
It ensures that adequate gas flow is maintained and reduces the possibility of backfires and burn backs
40
Define speed of flame propagation
The speed that the flame travels in premixed gases
41
B) the maximum safe working pressure for acetylene is ________kPa(_______psi)
103kPa or 15psi
42
C) acetylenes explosive limit in air is from_______% to ________%
2.5% to 80%
43
D) acetylenes explosive limit in pure oxygen is from ________% to ________%
3% to 93%
44
What percentage of O2 is in air?
a) 78.03%
b) .94%
c) 20.99%
d) .034%
There is c) 20.99% O2 in the air.
There is also
N2 is 78.03%
Ar is .94%
CO2 is .034%
45
In the _______ ___________ process, equipment purifies air, then compresses and cools it to a liquid at a temp of -317°F. The temp is then raised to -295°F which converts the N2 to a gas form.
Air liquefaction process
46
When a hose is ruptured what is the order of operations for shut down?
Extinguish the fire
Stop the flow of O2
Stop the flow of the fuel gas
1. Stop the flow of O2
2. Stop the flow of the fuel gas
3. Extinguish the fire
47
What may occur if oil or grease comes into contact with pure O2 under slight friction or pressure?
a) no reaction
b) violent explosion may occur
c) release of dangerous vapours
b) violent explosion may occur
48
What is the chemical formula of Acetylene?
a) C1H2
b) C2H2
c) C2H1
d) C1H1
b) C2H2
49
Describe the properties of Acetylene
Color & smell
Acetylene is colorless & smells like garlic however you may smell acetone (nail polish remover) when released from a cylinder.
50
How is Acetylene created?
a) in an Acetylene generator
b) by combining calcium carbide and water
c) Acetylene is not a hydrocarbon compound it can not be made
d) both a & b
d) both a & b
51
At what part of the flame is the hottest?
a) the end of the inner cone
b) the end of the outer cone
c) the end of the feather
d) the end of the outer envelope
a) the end of the inner cone
52
What is the explosive range of C2H2 in air?
a) 5.3 - 14
b) 2.3-9.5
c) 2.5-80
c) 2.5-80
53
What is the explosive range of C2H2 in O2?
a) 2.4-60
b) 3.0-93
c) 5- 59
b) 3.0-93
54
What is the critical point of C2H2?
a) 20psi
b) 35psi
c)15psi
d) 28psi
d) 28psi
55
If the temp is higher than 70°F does the pressure at which C2H2 becomes critical is:
a) lower than 28psi
b) higher than 28psi
a) lower than 28psi
56
What is the MSWP (max safe working pressure) of C2H2?
a) 10psi
b) 15psi
c) 20 psi
d) 30psi
b) 15psi
57
What temp does C2H2 have a neutral flame?
a) 5600°F
b) 4580°F
c) 5200°F
d) 4600°F
a) 5600°F
Acetylene has a neutral flame at 5600°F
58
What temp does propylene have a neutral flame?
a) 5600°F
b) 4580°F
c) 5200°F
d) 4600°F
c) 5200°F
59
Which fuel gas is ideal for heating operations and for cutting materials 6" or thicker?
a) Propane
b) C2H2
c) Natural Gas
d) Propylene
a) Propane
60
What is the O2 to fuel gas ratio for C2H2
a) 4-4.5:1
b) 1.5:1
c) 2.6:1
d) 1.1:1
d) 1.1:1
61
How many full sized gas cylinders is 160 L container of liquid O2 equal to ?
a) 20 full sized cylinders of gaseous O2
b) 18 full sized cylinders of gaseous O2
c) 5 full sized cylinders of gaseous O2
d) 10 full sized cylinders of gaseous O2
b) 18 full sized cylinders of gaseous O2
62
O2 cylinders are hot drawn, what does that mean?
O2 cylinders are formed from one piece of steel & hot worked so there are no seams, this enables them to contain higher pressures than welded cylinders
63
What are the two most popular sizes of cylinders?
a) 122ft3 (half sized) & 244ft3 (full sized)
b) 100ft3 (half sized) & 200ft3 (full sized)
c) 150ft3 (half sized) & 300ft3 (full sized)
d) 125ft3 (half sized) & 250ft3 (full sized)
a) 122ft3 (half sized) & 244ft3 (full sized)
The pressure is the same in both, only the volume changes
64
How often are cylinders tested by the manufacturer? Every _________ years & every ______ after the first retest.
Cylinders are tested every 10 years & every 5 years after the first retest.
65
What do you mark the empty cylinder when you switch to a new bottle?
MT & move it to specified storage for pickup
66
What hand threads do O2 tanks have?
Right hand threads
67
Does an O2 cylinder have a fixed draw limit?
No O2 can be drawn as fast as you want without issue.
68
What is the draw limit for C2H2?
1/7 of its volume per hour
or
can not be totally emptied in less than 7 hours
69
Match the O2 temps with their corresponding pressures.
Temperature °F
100
70
-20
Pressure in PSI
2380
1660
2200
100°F - 2380psi
70°F - 2200psi
-20°F - 1660psi
70
What volume is in an O2 tank with a pressure of 2200psi?
a) 140ft3
b) 190ft3
c) 244ft3
c) 244ft3
71
What safety feature does an O2 cylinder have to protect against extreme pressure rise caused by heat or fire?
a) check valve
b) metal rupture disk
c) lead plug
b) metal rupture disk
72
At what pressure does an O2 cylinders metal rupture disk burst?
a) 1200psi
b) 2200psi
c) 3200psi
d) 4200psi
c) 3200psi
73
What is the difference between O2 cylinders and C2H2 cylinders?
a) O2 tanks are welded, C2H2 tanks are hot drawn
b) C2H2 tanks are welded, O2 tanks are hot drawn
c) C2H2 tanks have fusible metal plugs where O2's dont.
d) both b & c
d) both b & c
C2H2 tanks are welded and have fusible metal plugs where O2 tanks are hot drawn out of one sheet of metal
74
At what pressure is C2H2 unstable?
a) >5psi
b) <10psi
c) >15psi
d) >20psi
c) >15psi
by its self C2H2 under pressures above 15psi is subject to spontaneous ignition. This is why cylinders are filled with porous material.
It keeps the C2H2 dissolved in the acetone due pressure in small spaces.
75
What percentage is a C2H2 cylinder filled with Acetone?
a) 20%
b) 30%
c) 40%
d) 50%
c) 40%
76
When should a cylinder of C2H2 weigh less than the stamped weight on the cylinder?
a) when empty and being refilled
b) when full, C2H2 is lighter than air
c) never, if lighter than the stamped weight acetone has been drawn off
d) there is no weight stamp on a C2H2 cylinder
c) never, if lighter than the stamped weight acetone has been drawn off
77
What filler materials are used in C2H2 cylinders?
There are 5
Lime
Silica
Celite
Asbestos
Water
78
What are the 2 types of valves used on C2H2 cylinders?
Keyed type - never opened more than 1- 1.5 turns
Wheel type
79
What is the only accurate method of determining the amount of C2H2 used on a job?
Weighing the cylinder
80
At what temp do fusible metal plugs melt?
a) 200°F
b) 212°F
c) 250°F
d) 262°F
b) 212°F
81
How far apart must you store O2 and C2H2 cylinders apart from one another?
a) you can store them together
b) 20'
c) 40'
d) 50'
b) 20'
82
What type of metal fittings must you never use with C2H2?
a) titanium
b) red brass
c) copper
d) both b& c
d) both b& c
Both copper and red brass react with C2H2 as it forms a residue that can heat and lead to an explosion.
83
Who regulates the identification of gasses used in industry?
a) ANSI
b) CGA
c) CSA
d) TDGS
a) ANSI
American National Standards Institute
84
What are the 2 main functions of a regulator?
To reduce source pressure to working/operating pressure
To deliver the gas at a constant delivery pressure regardless of pressure changes at the source
85
What are the 3 main working parts of a regulator?
a) Diaphragm, spring, valve stem
b) Chamber, valve stem, adjusting screw
c) Spring, diaphragm, valve/seat assembly
c) Spring, diaphragm, valve/seat assembly
86
Match the regulator with its description
Single stage regulator
2 stage regulator
1. used on manifold systems and can regulate pressures at a high degree of accuracy
2. are used where slight pressure changes do not adversely affect performance
Single stage regulators are used where slight pressure changes do not adversely affect performance
2 stage regulators are used on manifold systems and can regulate pressures at a high degree of accuracy
87
What type of regulator
1. reduces cylinder pressure to a pre-set intermediate pressure (180-400 psi)
2. reduces the intermediate pressure to the adjustable working pressure
2 stage regulator
88
What is in a regulator that is connected to a mechanism that actuates a needle indicator?
Bourdon tube
89
When storing regulators should you?
a) tighten the adjusting screw all the way
b) tighten the adjusting screw just enough to put pressure on the diaphragm
c) loosen the adjusting screw until almost out and no pressure is incurred
d) loosen the adjusting screw until diaphragm is released
b) tighten the adjusting screw just enough to put pressure on the diaphragm- this prevents the seat from corroding and becoming stuck by allowing the valve to come off the seat and allow air movement
90
What is the bursting pressure for oxyfuel hoses?
a) 200psi
b) 400psi
c) 600psi
d) 800psi
b) 400psi & the hoses must meet CSA standards
91
Hoses for fuel gas are what color_________
Hoses for O2 are what color_________
Hoses for fuel gas are red
Hoses for O2 are green
92
What do flash back arrestors do?
a) prevents flames from travelling back into the torch handle to the regulator
b) prevents flames from travelling back into the hoses to the regulator
c) prevents flames from travelling back into the regulator to the cylinder
a) prevents flames from travelling back into the torch handle to the regulator
93
Both are causes of creep, which is the main cause of creep?
a)The regulator leaks from the rear cover when the 1st stage valve leaks due to a diaphragm failure
b) The regulator leaks from the front cover when the 2nd stage valve leaks due to a diaphragm failure
b) The regulator leaks from the front cover when the 2nd stage valve leaks due to a diaphragm failure
94
Is replacing O-rings, seals or gaskets maintenance you can do to your torches or must you have them repaired by a qualified and competent repair person?
Replacing O-rings, seals or gaskets is a part of torch maintenance I can do myself.
95
Do flat faced fittings or bull nose fittings need a fibre washer ?
Flat faced fittings need fibre washersW
96
What area of an oxyfuel set up are susceptible to burn backs and backfires?
a) hoses
b) regulators
c) torch head
d) torch handle
c) torch head
The entire torch from tip to attachment nut
97
What area of an oxyfuel set up are susceptible to flashbacks?
a) hoses
b) regulators
c) torch handel
d) all of the above
d) all of the above
from the torch attachment nut all the way back to and including the regulators are susceptible to flashbacks
98
Which torch malfunction reestablishes itself with a bang or pop?
a) flashback
b) burn back
c) backfire
c) backfire
99
What is the main cause of backfires?
a) to little gas speed
b) a dirty tip
c) partial obstruction of gas flow
d) a hot tip
a) to little gas speed
100
What is the main cause of burnbacks?
a) hot tip
b) tip offices are enlarged & dont give adequate gas flow
c) faulty torch body seats that allow gasses to mix before entering the mixer
c) faulty torch body seats that allow gasses to mix before entering the mixer
101
Which of the torch malfunctions is the most serious?
a) flash back
b) burn back
c) backfire
a) flash back
102
What are the two main causes of Flashbacks?
1. grossly unequal pressures
2. mildly unequal pressures plus an obstruction
3. Faulty manipulation of valves
1. grossly unequal pressures & 3. Faulty manipulation of valves
are the two main causes of flashbacks.
103
Explain speed of flame propagation ?
the speed a flame will travel or spread in premixed gasses
104
properly mixed C2H2 has a speed of flame propagation of aprox
a) 5 - 10 ft/sec
b) 17 - 25 ft/sec
c) 19 - 28 ft/sec
d) 22 - 30 ft/sec
b) 17 - 25 ft/sec
105
Can you reduce a flame to the point where C2H2 is alone and smoky?
No - working in C2H2's smoke range means you have a low gas speed and results in backfires
106
List the 3 types of flames in order from coldest to hottest.
1. Neutral flame
2. Carbonizing/carburizing/reducing flame
3. Oxidizing flame
3, 1, 2
107
what is the main purpose of a regulator
a) accurately show the working pressure
b) register cylinder and working pressures
c) reduce source pressure to working pressure
d) accurately register the volume of gas being used
c) reduce source pressure to working pressure
108
An oxy-acetylene hose could be safely repaired by:
a) wrapping the break with black tape
b) using red brass fittings
c) using yellow brass fittings
d) using copper fitting connectors with a fiber washer
c) using yellow brass fittings
109
Faulty, leaky or damaged O2 cylinders should
a) be repaired onsite
b) emptied of contents
c) placed in an enclosed area
d) removed from the worksite
d) removed from the worksite
110
How can you identify an O2 hose?
a) measure hose diameter
b) check the hose fittings
c) identify the material composition
d) check the flow direction by the check valves
b) check the hose fittings
O2 hoses are also green
111
The first step of putting out a fire on an oxygen-acetylene set up:
a) close the O2 cylinder
b) close the C2H2 cylinder valve
c) use a fire extinguisher on the hoses
d) kink the hoses to reduce the gas flow.
a) close the O2 cylinder
112
The draw limit on a full sized cylinder is:
a) 15 psi/hr
b) 75 cubic feet per hour
c) no fixed draw rate
d) 1/7 of the cylinders volumetric capacity per hour
d) 1/7 of the cylinders volumetric capacity per hour
113
Pressure in the open lines of a C2H2 manifold system must not exceed
a)103 kPa (15psi)
b) 124 kPa (18psi)
c) 152 kPa (22psi)
d)193 kPa (28psi)
a)103 kPa (15psi)
114
The elements of Acetylene gas are
a) hydrogen and oxygen
b) carbon and hydrogen
c) carbon and oxygen
d) hydrogen and acetone
b) carbon and hydrogen
115
Which gas will not burn?
a) C2H2
b) O2
c) hydrogen
d) propane
b) O2
116
What is the percentage of calcium silicate in an acetylene cylinder
a) 50
b) 65
c) 90
d)100
c) 90
117
What actions may be necessary to remedy a gas leak or flames occurring between the torch handle and the mixer
a) shut off the torch valves
b) replace the damaged mixer seats
c) tighten the mixer nut with a wrench
d) use and oil based seal on the threads
b) replace the damaged mixer seats
118
What is the lowest % of C2H2 in air that is considered to be explosive?
a) .5
b) 2.5
c) 5.5
d)7.5
b) 2.5
119
Which fluid is used to check for leaks on oxygen-fuel equipment
a) open flame
b) leak detection fluid / soapy water
c) ammonia
d) oil based products
b) leak detection fluid / soapy water
120
The pressure safety device on O2 cylinders is located:
a) at the bottom of the cylinder
b) around the neck of the cylinder
c) around the rear side of the cylinder valve
d) the valve is designed to release high pressures through the seat arrangement
c) around the rear side of the cylinder valve
121
Propane is used regularly for O2 cutting and heating operations because of:
a) its high BTU potential
b) its availability and low cost
c) its ability to cut 6 inch thick steel
d) all of the above
d) all of the above
122
What safety precaution should be taken when compressed gas cylinders are not in service?
a) laid flat on the floor
b) mark on top with MT
c) moved to an outside area
d) replace the valve protection caps
d) replace the valve protection caps
123
How is N2 produced
a) natural gas deposits
b) during the air liquefaction process
c) through mixing of laboratory chemicals
d) oil production, produces trace gasses where N2 is collected
b) during the air liquefaction process
124
Which of the following is a commercial method of producing O2?
a) air purification
b) air liquefaction
c) electrolysis of air
d) fractional distillation of water
b) air liquefaction
125
What is the purpose of a flashback arrestor?
a) to release gas into the atmosphere if a fire breaks out
b) prevents the reverse flow of gasses to the regulators
c) prevent flames travelling from the torch to the regulators
d) to provide sufficient amount of gas to the torch for ignition
c) prevent flames travelling from the torch to the regulators
126
Oiling oxy-acetylene equipment, keeps the threads lubricated and is a good weekly practice T/F
F. Never use oil/grease products on oxygen-acetylene equip.
127
The neutral flame reaches a temp of aprox:
a) 2200°C 4000°F
b) 2750°C 5000°F
c) 3090°C 5600°F
d) 3850°C 7000°F
c) 3090°C 5600°F
128
A fully charged acetylene cylinder can contain:
a) 2200 psi of acetylene
b) limestone and coke
c) 90% acetone
d) a porous substance to keep acetylene dissolved in acetone
d) a porous substance to keep acetylene dissolved in acetone
129
If a compressed gas cylinder is leaking you should:
a) repair it and return it to service
b) transfer the contents to another cylinder
c) continue to use it and then take it back to the supplier
d) place it outside, tag it to identify the fault and notify the supplier
d) place it outside, tag it to identify the fault and notify the supplier
130
If the gas speed is slower than the speed of flame propagation, which of the following will likely occur?
a) a backfire
b) a flashback
c) a damaged mixer
d) a burn back
a) a backfire
131
Of the gasses listed which are considered to be fuel gasses
a) Nitrogen
b) Helium
c) Carbondioxide
d) Acetylene
d) Acetylene
132
Oxy- acetylene cylinders must be kept clear of arc welding equipment because
a) welding current can cause static charge igniting the C2H2 gas
b) an accidental arc strike on a cylinder could cause a fire or explosion
c) carbon or smoke from C2H2 can reduce the conductivity in copper windings
d) all of the above
b) an accidental arc strike on a cylinder could cause a fire or explosion
133
How does an increase in temp affect the pressure at which the critical point of C2H2 is changes
a) temp does not affect pressure
b) as temp increases, critical pressure will become higher
c) when temp increases, critical pressure will become lower
d) when ten increases, critical pressure will become higher
d) when ten increases, critical pressure will become higher
134
An C2H2 cylinder with a hand wheel valve, that leaks around the stem should be
a) opened 1-1/2 turns
b) opened 2 - 2 1/2 turns
c) opened all the way
d) replaced
d) replaced
135
How are C2H2 cylinders constructed :
a) welded
b) hot drawn
c) forged cast steel
d) riveted construction
a) welded
136
Which of the following is not a component of a regulator body
a) diaphragm
b) bourdon tube
c) valve assembly
d) adjusting screw
b) bourdon tube
137
The machine used to produce C2H2 is called an:
a) acetylene reactor
b) electric generator
c) acetylene generator
d) calcium carbide
c) acetylene generator
138
The speed of flame propagation that exists in a properly balanced mixture of O2 and C2H2 is:
a) 3-15 ft/s
b) 17-25 ft/s
c) 57 - 68 ft/s
d) 46-75 ft/s
b) 17-25 ft/s
139
The regulator gauge with the lowest numerical calibration will display the pressure:
a) in the cylinder
b) of mixed gasses
c) of inlet gas to the regulator
d) of gas pressure avail to the cutting tip
d) of gas pressure avail to the cutting tip
140
Contents in a compressed cylinder are best identified by:
a) the ANSI markings on the bottle
b) the AWS markings on the bottle
c) the CSA markings on the bottle
d) the CWB markings on the bottle
a) the ANSI markings on the bottle
141
Do O2 cylinders have a draw off limit
a) yes
b) no
c) yes, when ambient temps are below freezing
d) no, you can open the valve fully and allow it to vent in the atmosphere
b) no
142
A compressed O2 cylinder at 21°C will contain _______cu ft.
a) 144
b) 244
c) 1470
d) 2200
b) 244
143
The purpose of a manifold system with acetylene cylinders is to
a) supply the need for large volumes of acetylene
b) provide a safety factor against sudden pressure increases
c) protect the fusible plugs from damage caused by changing cylinders
d) mix the gasses from multiple cylinders providing better quality fuel gas
a) supply the need for large volumes of acetylene
144
A typical application for a 2 stage regulator would include
a) individual oxyfuel outfits
b) sensitive instrumentation systems
c) fuel gas distribution pipeline station outlets
d) occurrences where slight changes in delivery pressure are acceptable
b) sensitive instrumentation systems
145
The explosive range of acetylene in an O2 rich atmosphere is
a) 3-93 %
b) 2.5 - 80%
c) 5.3 - 14%
d) 5 - 59%
a) 3-93 %
146
The hottest part of an oxygen-acetylene neutral flame is located:
a) at the end of the torch
b) at the feather of the cone
c) at the end of the inner cone
d) at the end of the outer envelope
c) at the end of the inner cone
147
What is the % of acetone in an acetylene cylinder
a) 40%
b) 60%
c) 80%
d) 90%
a) 40%
148
When using a 2 stage regulator, what is the middle pressure called after it has been reduced from working pressure in the 1st stage, but before it has been reduced to the working pressure in the second stage?
a) flow pressure
b) adjusting pressure
c) transition pressure
d) intermediate pressure
d) intermediate pressure
149
What is the safety device on a manifold system
a) flash back arrestors
b) check valve
c) flashback tank
c) flashback tank
150
What is the % of Calcium silicate content in a C2H2 cylinder
a) 20%
b) 50%
c) 70%
d) 90%
d) 90%
151
What occurs when combustion occurs steadily in the tip and the mixer
- the mixes of gas is to lean for proper combustion
- has scratching sound
a) flash back
b) burn back
c) backfire
b) Burn back
152
Temp of a neutral flame
a) 4000°F
b) 5600°F
c) 6000°
d) 6600°
b) 5600°F
