Equipment - Metric Flashcards
Deciphering Cylinder Hieroglyphics
Which of the following cylinder markings designates the type of metal used to construct the scuba cylinder?
a) 3AL
b) 7@89
c) 675432
d) 3000
a) 3AL
Deciphering Cylinder Hieroglyphics
Which of the following cylinder markings designates the hydrostatic test date?
a) 3AL
b) 7@89
c) 675432
d) 3000
b) 7@89
Deciphering Cylinder Hieroglyphics
The (+) designation that appears on _____________ cylinders denotes that the cylinder may be overfilled to ________ beyond its working pressure.
a) steel/15%
b) aluminum/10%
c) steel and aluminum/10%
d) steel/10%
d) steel/10%
Cylinders – Materials
A steel cylinder whose capacity is 2016 litres at 168 bar and an aluminum cylinder whose capacity is 2265 litres at 203 bar are both filled to 133 bar. Which cylinder contains more air?
a) The steel cylinder
b) The aluminum cylinder
c) Both would hold equal amounts.
d) The answer cannot be determined from the information given.
a) The steel cylinder
The steel cylinder contains more air. To answer this question, you need to compare how much capacity each “bar” accounts for. In steel cylinders each “bar” accounts for 12 litres (2016 litres divided by 168 bar = 12 litres per bar). In an aluminum cylinder each “bar” accounts for 11.15 litres (2265 litres divided by 203 bar = 11.15 litres per bar). These constants can now be used to quickly determine how much capacity remains in a cylinder of a certain pressure. In the question, a steel 2016 litre cylinder filled to 133 bar contains 1596 litres (12 litres per bar x 133 bar = 1596 litres). An aluminum 2265 litre cylinder contains only 1482.95 litres (11.15 litres per bar x 133 bar = 1482.95 litres).
Cylinders – Materials
Aluminum cylinders were introduced because aluminum is a stronger metal and enables higher working pressures than in steel cylinders.
True
False
False
Cylinders – Features
What are the advantages of a DIN connector over the standard yoke screw system? (choose all that apply)
a) A better seal between the cylinder and regulator
b) Less expensive
c) Stronger connection
d) Less likely to freeze
a) A better seal between the cylinder and regulator
c) Stronger connection
Cylinders – Features
To prevent a scuba cylinder from rupturing due to overpressurization, a burst disk is installed in the _____________, and is designed to rupture when the cylinder pressure rises above about _____________ of the cylinder’s rated pressure.
a) regulator/200%
b) cylinder neck/225%
c) valve/140%
d) submersible pressure gauge/125%
c) valve/140%
Cylinders - Features
A burst disk only needs to be replaced if it ruptures.
True
False
False
Cylinders - Features
Why does a burst disk vent to the sides rather than straight out?
a) Venting straight out takes longer.
b) Venting to the sides takes longer.
c) To prevent the cylinder from potentially spinning.
d) To prevent condensation in the valve.
c) To prevent the cylinder from potentially spinning.
Scuba Cylinder Care and Maintenance
Why is it important to avoid any process involving heat treatment when having a scuba cylinder painted or refinished?
a) To avoid weakening the cylinder’s metal.
b) Painting a cylinder is unnecessary.
c) To prevent the cylinder from rusting.
d) To avoid contaminating the cylinder’s interior.
a) To avoid weakening the cylinder’s metal.
Scuba Sylinder Care and Maintenance
To ensure the structural integrity of a scuba cylinder, it should be _____________ anytime it is _____________.
a) destroyed/at an age of twenty years
b) hydrostatically tested/exposed to temperatures above 82°C/180°F
c) visually inspected/left unused for more than two years
d) All of the above are correct
b) hydrostatically tested/exposed to temperatures above 82°C/180°F
Scuba Cylinder Care and Maintenance
During a hydrostatic test a scuba cylinder is placed in a water-filled chamber. The cylinder is then filled with compressed air and the amount of expansion that occurs in the cylinder is measured by the amount of water that is displaced.
True
False
False
Scuba Cylinder Care and Maintenance
To what pressure is a scuba cylinder filled during a hydrostatic test?
a) 340 bar
b) 200% of its working pressure
c) 5/3s of its working pressure
d) The exact pressure depends upon what happens to the cylinder once it is pressurized.
c) 5/3s of its working pressure
Scuba Cylinder Care and Maintenance
Under what circumstances should a scuba cylinder be visually inspected?
a) If loose material is heard rolling around inside the cylinder
b) If a red or green accumulation is seen on the filter of the regulator first-stage
c) Once every year even if the cylinder appears in good condition
d) All of the above are correct.
d) All of the above are correct.
Scuba Cylinder Care and Maintenance
During a visual inspection on a scuba cylinder, what it the technician looking for? (choose all that apply)
a) Hydrostatic pressure.
b) Severe exterior damage.
c) Severe interior corrosion.
d) Galvanic action between the cylinder and valve.
b) Severe exterior damage.
c) Severe interior corrosion.
d) Galvanic action between the cylinder and valve.