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PADI > Equipment > Flashcards

Equipment Flashcards

1
Q

What markings should tanks have?

A

Max working pressure
Material
Hydrostatic/ pressure test date

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2
Q

Steel tank description and advantages

A

Round base
Normal working pressure of 220 bar
More negatively buoyant (better for cold water with dry suits)
When pressure drops, buoyancy of diver isn’t affected

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3
Q

Aluminium tank description and advantages

A

Flat bottom
220 bar working pressure
Last longer and easier to clean as produce aluminium oxide instead of rust
Can use with higher working pressures
More buoyant - when pressure drops, diver needs to add more weight

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4
Q

Visual inspection

A

Recommended once a year for steel and aluminium
Looks for corrosion inside tanks
Checks threading at neck of tank

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5
Q

Hydrostatic testing

A

Every 5 years in US, every 4 years in UK

Tank is pressurised to 7/5 it’s working pressure and then checked for damage

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6
Q

When should a hydrostatic test be done before it’s due date?

A

After tank is exposed to these conditions:
Tumbling or sandblasting to remove corrosion
Damage due to impact
Temperatures above 82C

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7
Q

K valves

A

Normal valve on tank that will open or close allowing the tank pressure out of the tank
Fitted with a DIN or yoke valve for attachment to the first stage
DIN screws in to K valve

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8
Q

What is a burst disc?

A

Thin copper disc that will break if the pressure in the tank is too high
Instead of exploding, the air will come out of the burst disc

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9
Q

J valve

A

Also called reserve valve - used before pressure gauges came into use
Spring loaded valve that shuts off when pressure gets low - the diver could then reach back and pull a pin to reopen it, but would know they have a reserve amount of air left
When filling the pin needs to be in down position

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10
Q

Purpose of first stage

A

Reduces pressure to intermediate pressure (9-13 bar) through low pressure hoses
Guides high pressure air to gauge

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11
Q

Balances vs unbalanced regs

A

Unbalanced - tank pressure resists and assists the opening and closing of valve in the first stage, directly affecting breathing resistance due to pressure, air in tank or use of AS
Balanced - neither resist nor assist so supply s constant resistance

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12
Q

How does the 2nd stage work?

A

As diver breathes, diaphragm moves inwards and presses down on a lever, moving the valve and allowing the air in the low pressure hose to enter

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13
Q

What is the downstream valve?

A

Opens with the flow of air (valve in the 2nd stage)

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14
Q

What is the upstream valve?

A

Valve in 2nd stage that opens against the flow of air

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15
Q

What is a fail safe valve?

A

If valve fails it will remain in the open position causing a free flow

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16
Q

What is environmental sealing?

A

Seal of silicone or grease around the first stage to stop it freezing in cold waters

17
Q

Capillary depth gauges

A

Simple piece of clear tubing, closed at one end and open at the other
Work using Boyles law
Hard to read accurately

18
Q

Open bourdon tube gauges

A

Spiral shaped tube
Water enters one end - increasing pressure causes tube to straighten which causes needle to move
As it is open it is liable to clogging

19
Q

Oil filled gauges

A

Use bourdon tube design but using a sealed tube in an oil filled gauge housing
Pressure increasing causes the tube to coil more tightly which moves the needle
Doesn’t clog as is sealed

20
Q

Diaphragm gauges

A

Connect a flexible diaphragm to levers and gears that move the needle

21
Q

Digital gauges

A

Measure pressure using a transducer which varies the electricity it transmits depending on the pressure

22
Q

SPG

A

Work on same principle as bourdon tube gauges

23
Q

What are the industry guidelines to do with nitrox cylinders?

A

Must be O2 cleaned if using more than 23%
Must be cleaned and lubricated specially if using more than 40% (40% rule) and must be cleaned again if filled using a normal air source

24
Q

EAN cylinder markings

A

15cm band at tank shoulder - top and bottom should be yellow 2.5cm band with centre section green + labelled EAN
Visual inspection sticker
Label with current blend, fill date, MOD of current blend and analyser name

25
Q

How much weight needs a lifting bag?

A

4-7kg

26
Q

How do you measure distance?

A

Arm spans

27
Q

What way do the currents flow globally?

A

Northern hemisphere - clockwise

Southern Hemisphere - anti-clockwise

28
Q

Why do waves break?

A

Bottom topography

29
Q

Describe a DIN valve

A

Screws in

Allows higher pressure

30
Q

How does an SPG work?

A

C shaped or spiral tube that straightens causing needle to move

31
Q

3rd method taught for out of air situation in OWC

A

CESA

32
Q

Jellyfish sting treatment

A

Vinegar
Rubbing alcohol
Diluted household ammonia

PADI (5 decks)

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