Transcript Rebreather presentation

TDI Inspiration and Evolution
Closed Circuit Rebreather Diver
Course
TDI Inspiration and Evolution
Closed Circuit Rebreather Diver Course
Overview of Course Structure
• 1 - Introduction and Welcome
• 2 - The History and Development of Rebreathers
• 3 - Mechanics of the inspiration and Evolution
• 4 - Classic Electronics Control (Optional)
• 5 - Vision Electronics Control (Optional)
• 6 - Physiology - A Reflection for the CCR Diver
TDI Inspiration and Evolution
Closed Circuit Rebreather Diver Course
Overview of Course Structure continued
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7 - Let’s Go Diving the Rebreather - Preparation
8 - Let’s Go Diving the Rebreather - In the Water
9 - Avoiding Rebreather Incidents - Safe Diving
10 - Mod 2 Extension (Optional extra course)
11 - Mod 3 Extension (optional extra course)
TDI Inspiration/Evolution Family
of Rebreathers Divers Course
Section 1:
Introduction and Welcome
Introduction and Welcome
• Congratulations of enrolling in a most thrilling
experience with Inspiration/Evolution technology
• Welcome to a new way of thinking about diving
• Understand that you are ALL novices again
• You will develop new skills for CCR diving
including:
– Attitudes
– Disciplines
– Awareness
Introduction and Welcome
Who the course is for and what you can expect to get out of it.
• COURSE PREREQUISITES
– 18 years of age
– Logged 100+ dives
– Nitrox and Advanced Nitrox training
• COURSE CREDENTIALS
– To become qualified to dive the Inspiration/Evolution family of
rebreathers on either Classic or Vision Electronics or both
(double certification and extra dives) on Air Diluent up to
40m/132ft with safety stops and 5 minutes max deco at 6m/
20ft
Introduction and Welcome
• Why CCR Diving
– Longer dive durations possible with very
little equipment
– Almost silent and bubble free unless
ascending
– Extremely efficient use of breathing gas
– Optional Nitrox mix for all depths according
to user-selectable PPO2 setpoint
– Warm and moist comfortable breathing gas
reducing risk of hypothermic tendencies
Introduction and Welcome
• What else can you expect to experience on this course?
– Many new terms for CCR not used in OC or SCR diving
– Change from a constant percentage Nitrox mix in OC to
a variable percentage Nitrox mix with constant partial
pressure in CCR mode
– Computer controlled gas injection system on ascent
causes accelerating bouyancy characteristics
• We need to think differently
– Jump a billion years of evolutionary development
• An opportunity to almost evolve into a sea-going mammal
with hours of sub-surface capability, and be back on land
again for another fun filled experience
TDI Inspiration/Evolution Family
of Rebreathers Divers Course
Section 2:
The History and
Development of Rebreathers
The History and Development
of Rebreathers
• Rebreathers in basic form have been around for
over a century underwater, and longer for mine
rescue work
• The earliest makes were pure oxygen devices
• The Englishmen Henry Fleuss achieves a major
milestone covering over 300 meters (1000 feet)
underwater in the construction of the Severn
railway tunnel a century ago
• Military rebreathers developed and used-Stealth
The History and Development
of Rebreathers
• The advent of readily available Nitrox to the recreational
market fuelled the development of recreational nitrox SCR
rebreathers
• Progress and need in the military theater saw the
development of a number of electronic controlled CCR
machines over the last two decades
• Some cave divers opted for passive mechanical SCR with
no electronics
• Makes include the Electrolung; Cis Lunar; Drager Atlantis,
Dolphin and Ray.
• We see the advent of recreational CCR’s with the Inspiration
in 1997, followed by Prism, Megalodon,Ouroboros, Optima
and Kiss, and in 2005 the Evolution
The History and Development
of Rebreathers
CONCEPTUAL REBREATHER DESIGN
• All need a scrubber for CO2 removal
• Pure Oxygen rebreather – no need for electronics in basic
form just keep manually adding gas when loop volume falls
• Semi Closed SCR uses a known nitrox for loop addition
• Mechanical rebreathers use a fractional volume technique to
refresh gas
• Either Passive by sucking in fresh gas when oxygen in the
loop volume is depleted and a diaphragm regulator re-injects
to bring loop volume back up, or
• Active – Constant flow rate of Nitrox to loop-vent excess
The History and Development
of Rebreathers
INSPIRATION AND EVOLUTION
• Closed Circuit rebreathers (CCR)
• State of the art electronic controls
• Onboard sources of air and oxygen, scrubber,
computer controlled variable Nitrox mixing
• Everything the recreational and technical diver
needs
TDI Inspiration/Evolution Family
of Rebreathers Divers Course
Section 3:
Mechanics and basic functioning
of the Inspiration and Evolution
rebreather systems
Mechanics and basic functioning
of the Inspiration and Evolution
• Diver’s Lungs
• Mouthpiece and
Hoses
• Exhalation
Counterlung
• Manual Inject Buttons
• Over Pressure
Release Valve
• The Scrubber
• The Scrubber
Cartridge
• The Lid and handsets
• Three Independent
Oxygen Sensors
• The Handsets and
Gas Control
• Battery Compartment
• Warning Buzzer
• Cell Connectors
• The Oxygen Supply
• Inhalation
Counterlung
• Diluent Gas Supply
Mechanics and basic functioning
of the Inspiration and Evolution
• Including Optional System Components
– Auto-Diluent Additional Valve (ADV) and inline
LP Flow Stop control device
– Vision Electronics System (Factory Purchase)
• Includes a redundant LED head-up Display (HUD).
Standard on the Evolution, the Vision package is
optional on the Inspiration.
• Optional Scrubber monitoring temperature sensing
“Stick”
Mechanics and basic functioning
of the Inspiration and Evolution
DIVERS LUNGS
• The motor that powers the gas around the
rebreather gas loop
• The point of exchange for O2 rich gas to the body
and CO2 rich gas from the body
• When we inhale, “clean” O2 rich gas comes in from
the left.
• The flow is from the divers lungs through the
mouthpiece to the right
Mechanics and basic functioning
of the Inspiration and Evolution
MOUTHPIECE and HOSES
• Mouthpiece and one-way mushroom valves
control direction of gas flow
• Timing of gas flow is in sympathy with diver’s
breathing pattern.
• Hoses are large bore. This reduces the work of
breathing (WOB)
• Mouthpiece hose is weighted for dynamic balance
- adjustable
Mechanics and basic functioning
of the Inspiration and Evolution
EXHALATION COUNTERLUNG
• Counterlungs come from the factory in 4 different
sizes – User Selectable
• Contains first fixed T-piece and “water-trap” flow
valve directing gas and water into the exhalation
counterlung
• Flexible breathing bag to contain gas from body
• Contains both the Manual Oxygen Addition Valve
and the Gas Loop Over Pressure Release Valve
Mechanics and basic functioning
of the Inspiration and Evolution
THE CO2 SCRUBBER (or Stack)
• Gas path is from the exhalation counterlung,
through the T-piece down to the bottom of the
CO2 scrubber
• It fans out to a large bore axial flow through the
scrubber to reduce gas velocity and increase
“Dwell Time” for CO2 removal
Mechanics and basic functioning
of the Inspiration and Evolution
THE SCRUBBER CARTRIDGE
• Designed to remove CO2 from the gas loop.
• Spring loaded to maintain air gap at bottom
• Designed with Hydrophobic membranes for
prevention of water absorption
• Contains upper and lower plastic retainers for the
scrubber material
Mechanics and basic functioning
of the Inspiration and Evolution
The Scrubber Cartridge – continued
• Different scrubber makes can give different
duration times due to different granule sizes
• Spacer and o-ring for prevention of gas by-pass
up the side of the scrubber canister
• Only designed to remove CO2, not any other toxic
compounds or contaminants in the breathing gas
Mechanics and basic functioning
of the Inspiration and Evolution
SCRUBBER MATERIALS
• Have a defined shelf life time and in use up to 3 hours
• Effectiveness altered by time, temperature and moisture
• Sofnolime 797 grade recommended ( Other makes include
Dragersorb and Sodasorb)
• Sofnolime is primarily a Sodium Hydroxide compound
• Needs proper packing to prevent CO2 channeling
• Efficiency is reduced by high gas flow rates (fast or skip
breathing) or focused “channeling” characteristics
• In a properly assembled and properly functioning CCR
system the CO2 scrubber is the “Achilles Heel”
Mechanics and basic functioning
of the Inspiration and Evolution
SCRUBBER MANAGEMENT
• No partial filling of the scrubber. New full
canister every time
• Do not empty scrubber into a bag and re-pack
the scrubber later- new and used granules are
then mixed
• Do not store partly used scrubber for more than
a few days. The material absorbs CO2 and
grows mold
Mechanics and basic functioning
of the Inspiration and Evolution
CONTROLLERS
GENERAL
• Power On
– No wet contacts
– Switch on manually
– Self testing electronics. Hear/see alarms and
hear solenoid firing
– 3 control buttons, but classic uses a separate
power switch also
Mechanics and basic functioning
of the Inspiration and Evolution
HANDSET CONTROLLER GENERALITIES
• Handset controllers are electronic – handle carefully
• There are two independent handset “controllers” on all
Inspirations/Evolutions
• The primary function of the controller is to control oxygen
injection and display real time information to the diver
• The controller also drives the alarm systems and interfaces
with the diver via 3 control buttons
• Can be switched on and off separately
• They are redundant in a Master/Slave combination
• Either controller can be the Master
Mechanics and basic functioning
of the Inspiration and Evolution
CONTROLLER LOCATIONS
• On the Inspiration Classic the controllers are in
the handsets
• On Vision Electronics the single handset is a
display and keypad only – the controllers are in
the Scrubber Lid
Mechanics and basic functioning
of the Inspiration and Evolution
THE SCRUBBER LID and HANDSETS
• The electronic “brains” of the device
• Function is to control the PPO2 of the breathing gas to a
user defined setpoint and display this and other dive
parameters to the diver visually (handset display) (and
HUD on Vision) and audibly (buzzer alarms)
• Great care should be taken when handling them
• For transport fully assemble rebreather or carry lid and
handsets separately in a padded bag
• Treat it with the same care as a laptop
Mechanics and basic functioning
of the Inspiration and Evolution
3 INDEPENDENT OXYGEN SENSORS
• 3 galvanic fuel cells each with a milli-volt output
proportional to the oxygen exposure across their outer
faces (breathing gas)
• Voting logic of the computer for oxygen control
purposes averages the nearest 2 readings and
ignores the 3rd
• This information is displayed to the diver as PPO2
values
• Delicate pin connections
• Should never smell of “toxic” or other vapors
Mechanics and basic functioning
of the Inspiration and Evolution
THE HANDSETS ( and HUD on Vision)
• Redundant controller PPO2 readings displayed to the diver
• Inspiration has 2 handsets, Evolution has 1 handset
• Provide for underwater dive menu changes to suit environment
• Must be switched on to have a chance to drive the oxygen solenoid
• Will give indications of battery health, controller health, and cell
health in real time, underwater
• Can drive audible and visual alarms
• Redundancy so that 1 controller can fail while the other allows you
to safely exit the water
• Need to constantly be checking PPO2 on the handset
Mechanics and basic functioning
of the Inspiration and Evolution
THE HANDSETS (and HUD on VISION) – continued
• Can drive audible and visual alarms
• Redundancy so that 1 controller can fail while the
other allows you to safely control the rebreather
and exit the water
• Need to constantly be checking the PPO2 on the
handset during the dive
Mechanics and basic functioning
of the Inspiration and Evolution
• CONSTANT PPO2 GAS CONTROL
• Remember Dalton’s Law from Advanced Nitrox
Pressure gas = FO2 x Pressure
• At different depths (gas pressures) for a constant
PPO2 controller setting we will have a Nitrox mix
that changes proportionally to pressure
• At any given depth we can calculate the Nitrox
mix for any given PPO2 setting
Mechanics and basic functioning
of the Inspiration and Evolution
Mechanics and basic functioning
of the Inspiration and Evolution
BATTERY COMPARTMENT
• Two slots for the two 2CR-P2 lithium 6 volt batteries
• Battery life typically 15 – 20 hours for the master
• Slave battery life longer – not firing the solenoid
Mechanics and basic functioning
of the Inspiration and Evolution
WARNING BUZZER (and HUD)
• Connected to the scrubber lid but normally fed to the Tpiece by diver’s left ear (HUD goes same way to left side of
mouthpiece)
• This is a secondary warning device, the handsets are the
primary indicators always
• In conditions of low battery power alarms may fail before
handsets do
• (The HUD provides green/red visual health status to the
divers direct area of vision)
Mechanics and basic functioning
of the Inspiration and Evolution
CELL CONNECTORS
• These are delicate and covered with red or blue
moisture caps with holes for pressure equalization
• Take great care not to damage wires or connectors
if changing cells
Mechanics and basic functioning
of the Inspiration and Evolution
THE OXYGEN SUPPLY
• Dive tank switched on
• HP to SPG on front of exhalation lung gives O2 pressure
• LP hose feeds O2 to the LID for the solenoid from the
first stage regulator
• First stage regulator I/P must be 7.5 Bar
• Evolution uses 2 liter cylinders, Inspiration uses 3 liter
cylinders
• Remember:- Rich mix Right, Lean mix Left
Mechanics and basic functioning
of the Inspiration and Evolution
INHALATION COUNTERLUNG
• O2 rich gas from the scrubber lid comes up to the
inhalation counterlung
• Blue color coded for hoses containing clean
oxygenated gas with the CO2 removed
• Passes through the inhalation T-piece without
“Water-Traps on the newer machines
• Blue Manual Diluent addition button at bottom of
inhalation counterlung
Mechanics and basic functioning
of the Inspiration and Evolution
DILUENT GAS SUPPLY
• Need to use diluent below 6msw (20fsw)
• Manually add diluent on descent depressing the blue manual
addition button on the inhalation counterlung “to equalize” the
loop volume with pressure changes
• LP feeds both the wing BCD and the Auto-air OC bailout
device
• Tank pressure is displayed on the SPG via HP hose over left
shoulder
• Do not use for Drysuit inflation – use off board gas
• IP normally set to 9.5 Bar
Mechanics and basic functioning
of the Inspiration and Evolution
OPTIONAL AUTO-ADDITION DILUENT VALVE –
ADV and FLOW STOP CONTROL DEVICE
• Replaces Inhalation T-piece and does not contain a
water-trap device
• Automatically allows diluent into the breathing loop
from the diluent side via a diaphragm if loop pressure
drops below ambient
• Flow Stop Control Switch on the LP hose from the
diluent first stage feeding the ADV can be used to
switch ADV off if free flowing or faulty
Mechanics and basic functioning
of the Inspiration and Evolution
BOUYANCY WING and AUTO AIR
• All Inspiration and Evolution CCR come fitted with
a wing and Auto-air as standard
• The bouyancy wing and Auto-air are fed by LP
feed from the diluent first stage
• The Auto-air is an OC 2nd stage regulator
connected directly to the diluent gas supply via
the first stage regulator
• The wing can be fitted with an optional “crackbottle” for alternate gas source inflation
TDI Inspiration/Evolution Family
of Rebreathers Divers Course
Section 4:
Classic Electronics Control
Classic Electronics Control
DUAL HANDSET CONTROLLERS
• Liquid Crystal display on each with protective
clear faceplate
• 3 white magnetic Hall-Effect control Switches –
spring loaded
• One black rotary power switch
• Power switch up = on
• Power switch down = Off
Classic Electronics Control
CLASSIC HANDSETS
• Separate Power On/Off switch – beware it can
get caught in your gear and get switched off
• Each handset shows if it is Master or Slave
• Each handset displays the three cell readings in
PPO2
Classic Electronics Control
• Each handset displays the current setpoint setting at the
top of the screen
• Alarms are shown in text on the screen
• There is a start-up menu that scrolls through basic pre-dive
conditions to check diluent, and asks if you would like to
calibrate and check the oxygen valve
• The dive menu in water allows setpoint changes and
changes to backlighting intensity
• Your Instructor will guide you through the cycle
TDI Inspiration/Evolution Family
of Rebreathers Divers Course
Section 5: Vision Electronics Control
Vision Electronics Control
VISION
• General
– Owners personal data is shown on screen
– Software Revision Version shown on screen
– Optional software versions are available for
Nitrox and Trimix diving
– Vision Electronics available in German, Dutch,
Italian, Spanish, Portugese, French and English
– Functionality and displays similar in many
respects to the classic Inspiration Handsets
Vision Electronics Control
SINGLE HANDSET SYSTEM
• Liquid Crystal display mounted in aluminum case
• 3 black buttons for commands
• Twin redundant controllers C1 and C2 housed in
Scrubber Lid
• Power on by left switch
• Power off by menu command by depressing right
2 buttons simultaneously
• Can select to power off C1 or C2(anytime) or All
Off but not underwater
Vision Electronics Control
SINGLE HUD DEVICE
• Dual redundant displays of twin LED’s one green one
red connected to C1 and C2
• Fiber optic cable running along mouthpiece hose
connects to controllers in Scrubber Lid
• Green LED’s are “Good”
• Red LED’s are ‘Rong’ or Alarms
• HUD lighting intensity is user selectable
• Read handset to get the detail of type of alarm
• Visual alarms generated with audible alarms
Vision Electronics Control
OPTIONAL SCRUBBER TEMP STICK
• Connects to Scrubber Lid via connectorised cable
and status is displayed on the handset
• It is NOT a CO2 monitor
• Temp Stick is a temperature sensing system to
detect where the main ‘Burn Face’ of CO2
absorption is taking place through the scrubber
segments
• It aids in scrubber maintenance monitoring
Vision Electronics Control
LCD HANDSET DISPLAY
• Switches automatically from Surface Mode to
Dive Mode at 1.2MSW ( 4FSW) and back again
at 0.9MSW (3FSW)
• The 3 PPO2 readings for the 3 cells are displayed
across the middle of the LCD
Vision Electronics Control
• Power on
– Will auto-check controllers, batteries, cells,
alarms and HUD. The temp stick, if fitted and
connected, will also be checked
– Your instructor will guide you through the
menus, but read the User Instruction Manuals
first
– Status of Vision system components are
displayed on the LCD as shaded or clear
elements
Vision Electronics Control
SUB MENU SELECTION
• Either CCR or DECO
• Deco theory and handset options and control is
covered fully in MOD 2 Course and is only
touched on in this program
• This Course addresses the Non-Decompression
diving fundamentals of the CCR
• Includes High and Low setpoint selection and
changes and optional handset adjustments.
Vision Electronics Control
Calibration
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Start-up asks if you want to calibrate
Can go direct to DIVE MODE for ‘Dry Dive’
Usually calibrate before each dive
Calibration procedure for cell mV output calibration
Prompts on screen to check O2 valve, diluent valve,
and system bailout
Vision Electronics Control
AUTO SETPOINT SWITCHING
• User selectable manual or automatically upon
reaching a pre-determined depth
• Latest S/W version allows different depths for
auto-switching on descent and ascent
Vision Electronics Control
BUTTON CONTROLS
• Center button is to select option on screen
• Outside two buttons to scroll up and down the
menu screens
• Left button powers on the Controllers
• Right two to enter power down sequence
TDI Inspiration/Evolution Family
of Rebreathers Divers Course
Section 6: Physiology –
A Reflection for the CCR Diver
Physiology – A Reflection for the
CCR Diver
BASIC PREMISE
• We need to breathe clean (CO2 and toxic gas free),
appropriately oxygenated gas at all depths at all times
to sustain life and to minimise DCS risk
• Appropriate nitrox mixes are delivered to the diver
under software control according to the PPO2 selected
by the diver
Physiology – A Reflection for the
CCR Diver
ADDITIONAL CONCEPTS
• The low and high PPO2 default setpoints of the
Inspiration and Evolution are set at 0.7 and 1.3
respectively
• Ascent must be controlled at less than 9m per minute
as per normal diving practice. DSC and DCI risks still
apply
• Dangers of hypoxia, hyperoxia, asphyxia and the
insidious CCR carbon dioxide poisoning (hypercapnia)
need examination
• Lets review sources of contamination of breathing loop
• NOAA toxicity guidelines apply for Whole Body and
Pulmonary Toxicity
Physiology – A Reflection for the
CCR Diver
CO2 and HYPERCAPNIA
• Humans consume O2 at a cellular level and
generate CO2 as a waste product
• Blood transports O2 to the cells and removes CO2
• Blood exchanges CO2 for O2 at the lung Alveoli
• The urge to breathe is driven by the level of CO2
retained in the body (blood and cells)
• With hypercapnia and elevated CO2 levels, the
breathing rate is increased (panting – dypsnea) to
try to vent the lungs and alveoli
Physiology – A Reflection for the
CCR Diver
HYPERCANPNIA SYMPTOMS
• Mild Symptoms
– Headache
– Anxiety and dizziness
– Shortness of breath
• Severe Symptoms
– Strong anxiety bordering on panic
– Muscular difficulty and loss of dexterity in closing
mouthpiece to bail out to OC
– Diluent flush doesn’t seem to have any effect at first so
divers often stop flushing when in fact they should
continue flushing non-stop
Physiology – A Reflection for the
CCR Diver
RE-INHALATION OF CO2
• CO2 normally removed by Sofnolime scrubber
• Conditions when this doesn’t occur properly
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–
–
–
–
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Scrubber expired or ignoring 3 hour duration rule
Strenuous activity on rebreather
Incorrect assembly of rebreather – missing O-ring
Wet or flooded scrubber
Damaged mushroom valves – gas goes backwards
Skip breathing or breath holding – creates pockets of
very high CO2 content in the breathing loop
– Incorrect scrubber packing
Physiology – A Reflection for the
CCR Diver
DEPTH VERSUS CO2
• As depth increases, work of breathing increases to
push more gas molecules around the breathing loop.
More CO2 is generated as a result.
• As gas density of molecules increases the efficacy of
the scrubber granules to absorb CO2 across its
surface decreases
Physiology – A Reflection for the
CCR Diver
HYPEROXIA
• Too much oxygen results in O2 toxicity risk
• Inspiration/Evolution alarm is set at a PPO2 of 1.6 or above
• Track O2 toxicity per NOAA tables (see manual)
• At a default setpoint of 1.3, NOAA limit = 180 minutes - But
80% of that is 144 minutes
• Do not exceed 80% of CNS and OTU tables
• Need to monitor CNS% and OTU’s carefully on multi-dive
days or multiple repeat dive days
Physiology – A Reflection for the
CCR Diver
SYMPTOMS OF HYPEROXIA
• CONVENTID
– CON Convulsions
–V
Visual disturbances/Tunnel vision
–E
Ears ringing (Tinnitus)
–N
Nausea
–T
Tingling or twitching (facial)
–I
Irritability
–D
Dizziness or vertigo
Physiology – A Reflection for the
CCR Diver
PULMONARY TOXICITY
• O2 causes the alveoli surfaces in the lung to dry
out thus slowly reducing lung efficiency
• OTUs – 1 minute of 100% oxygen breathing at
the surface
• Happens above a PPO2 of 0.5 thus very real
danger for CCR and Inspiration/Evolution diving
Physiology – A Reflection for the
CCR Diver
HYPOXIA
• Occurs if the PPO2 drops below 0.16 at any time
• Real danger on ascent if solenoid fails
• Real danger if Oxygen tank is off or empty
• Symptoms can typically be breathlessness and
panting, and lack of co-ordination
• Unconsciousness resulting in drowning can be
sudden and without warning
Physiology – A Reflection for the
CCR Diver
CNS TOXICITY AND OTU’s
• Real danger of convulsing and drowning if your
CNS is not monitored properly
• Always know the PPO2 in the loop and do a
diluent flush to check any odd readings
• Track your CNS % and OTU’s on the NOAA
tables in your manuals
Physiology – A Reflection for the
CCR Diver
ASPHYXIA
• Like strangulation it is caused by a shortage of
oxygen and buildup of CO2
• Restrictions in the breathing loop like a kinked
mouthpiece hose can cause it
• Easily noticed early in a dive
• Ineffective or exhausted scrubber also can cause
asphyxia
• Eventually results in unconsciousness
TDI Inspiration/Evolution Family
of Rebreathers Divers Course
Section 7:
Let’s Go Dive the Rebreather
- Preparation
Let’s Go Diving the Rebreather Preparation
EQUIPMENT ASSEMBLY and INSPECTION
• Preparation
– Assemble the rebreather according to a checklist (refer to
manual), initially under Instructor guidance
– Be meticulous and do not get distracted
Let’s Go Diving the Rebreather Preparation
Pay particular attention to the following during assembly and inspection;
•
Positive & negative pressure tests
•
HUD LEDs functioning (if HUD used)
•
Cylinder contents analysis
•
Alarm working audibly
•
Cylinder pressure on SPGs
•
•
Listen for solenoid firing and alarm
sounding when handsets switched on
Wing and Auto-Air checks
•
Switches on handsets working normally
•
Mushroom valve checks on the
mouthpiece assembly
•
Scrubber packing, O-ring and
spacer functioning
•
Hose O-ring lubrication
•
Battery power levels
Let’s Go Diving the Rebreather Preparation
WEIGHTING AND TRIM
• Ensure the unit is well weighted at the top.
• Add to the sides on the waistband to trim
• More weight needed if diving in a drysuit
Let’s Go Diving the Rebreather Preparation
MACHINE CALIBRATION
• Absolutely critical part of the preparation process
• Always put in % of oxygen in the lid at 98% - all
the air cannot be displaced from the lid
• Ensure the millibar pressure is correctly entered
• Is the Mbar reading on the Vision handset
correct? (Automatically sensed)
• Mbar readings are critical for altitude diving
• Watch the cell readings rise during calibration
and check for any “slow” or “limited” cells
Let’s Go Diving the Rebreather Preparation
Calibration of O2 cells O/P
– Your instructor will demonstrate
– Watch for rate of change of cell readings as
oxygen is injected to Scrubber Lid
– Only calibrate with the unit upright, vertical
and dry inside
Let’s Go Diving the Rebreather Preparation
• Calibration
–
–
–
–
Start-up asks if you want to calibrate
Can go direct to DIVE MODE
Usually calibrate before each dive
Calibration procedure for cell mV output
calibration
– Prompts on screen to check O2 value,
diluent value bailout
Let’s Go Diving the Rebreather Preparation
BATTERY POWER MANAGEMENT
•
•
•
•
2 x Lithium CRP2 batteries
One per handset/controller
Either change both batteries together, or cycle
New battery goes to slave, slave goes to master
and old master is discarded
• Backlighting consumes power
• Solenoid firing consumes power
• Alarms consume power
Let’s Go Diving the Rebreather Preparation
GETTING THE FEEL OF THE MACHINE ON LAND
• Putting on the machine for a “dry dive”
– Adjust straps to fit body correctly and tuck away
loose ends
– Power up and sequence handset control through
to dive mode under guidance of Instructor
– Go to a low setpoint of 0.5
– Put on mask to prevent breathing through nose
– Breathe on the machine while watching PPO2
readings on handsets listen for solenoid firing
Let’s Go Diving the Rebreather Preparation
• Dry dive simulations (approx 30 minutes)
• These provide useful simulations in a safe
environment for learning and troubleshooting
Let’s Go Diving the Rebreather Preparation
OVERFILLED BREATHING LOOP
• Allow loop volume to increase by injecting a
little diluent.
• Get the feel of “over pressurized loop”
inhibiting the exhale cycle
• Release excess gas – repeat again
Let’s Go Diving the Rebreather Preparation
UNDERFILLED BREATHING LOOP
• Exhale fully through the nose, twice
• Feel the effect of too little pressure in the loop,
difficulty inhaling properly
• Add gas using diluent button or, if there is an
ADV, turn it on for volume adjustment
Let’s Go Diving the Rebreather Preparation
NORMAL LOOP VOLUME
• Continue normal breathing mode while seated or
stationary
• Observe PPO2 readings and how closely they
follow the setpoint
• Listen to solenoid firing and ensure you are
feeling fine on machine
Let’s Go Diving the Rebreather Preparation
GENTLE EXERCISE
• Walk about with the rebreather on
• Simulate moderate exercise
• Notice breathing, rate increases, and solenoid
firing more often than when at rest.
Let’s Go Diving the Rebreather Preparation
INCREASED WORK LEVEL
• Jog in place for a couple of minutes, or do a few
squats with the machine on to raise heart and
respiratory rates
• Observe PPO2 tracking, hear solenoid firing
and notice little or no change in loop volume
• The student should still feel fine and have no
CO2 problems
Let’s Go Diving the Rebreather Preparation
LOW ALARM CHECK
• Sit, relax and come off the machine – breathe
normal air
• Blow air into the loop to drop the PPO2 below 0.4
• Check for alarms and observe PPO2 coming back
to setpoint again under automatic computer
control
Let’s Go Diving the Rebreather Preparation
REDUNDANT CONTROLLER CHECK
• Strictly under Instructor supervision
• Repeat Low Alarm Check with handset or
controller C1 switched off
• Ensure redundant controller works, initiates
alarms and brings PPO2 back to setpoint
• Switch handset or controller C1 back on again
Let’s Go Diving the Rebreather Preparation
SETPOINT CHANGES
• Switch to High and then back to the Low
Setpoint when the PPO2 rises to 0.9 and
observe PPO2 on handset
• Test how long it takes to breathe the loop back
down to a PPO2 of 0.5 at rest
Let’s Go Diving the Rebreather Preparation
OPEN CIRCUIT BAIL-OUT
• Close mouthpiece and come off the loop
• Switch to OC bailout – Auto-Air, take 3 breaths,
return to the loop and open mouthpiece
• Observe loop volume increase as O2 is injected
to bring PPO2 back up to setpoint because of the
air you introduce to the loop
• Alarm for Low PPO2 may also sound when
returning to loop and filling it with air
Let’s Go Diving the Rebreather Preparation
DILUENT FLUSH
• Inject diluent using manual addition button on
inhalation counterlung while breathing in
• Vent gas through over-pressure release valve
while exhaling
• Repeat three times and observe reduction in
PPO2. Listen to solenoid firing. It is possible that
the PPO2 may drop below 0.4 and cause an
alarm
Let’s Go Diving the Rebreather Preparation
MANUAL GAS ADDITION
• Give a small squirt of O2 with the manual
addition button and observe the PPO2 reading
• Repeat the exercise with diluent
• Repeat to get a “feel” for the addition buttons
TDI Inspiration/Evolution Family
of Rebreathers Divers Course
Section 8:
Let’s Go Dive the Rebreather
– In the Water
Let’s Go Diving the Rebreather –
In the Water
Rule No 1
• If in doubt – bail out!
Rule no 2
• If something feels wrong – it is!
Let’s Go Diving the Rebreather –
In the Water
DIVE PLANNING
• Select depth and time for a safe no-deco time
• Scrubber monitoring and planning (2.5 – 3 hour rule)
• Gas volume planning – enough for a bail-out
• Oxygen planning – CNS% and OTUs
• Is this a repetitive dive?
• Thermal protection appropriate for conditions and
duration of dive
• Brief team, do ABCs and enter the water under
guidance of your Instructor
Let’s Go Diving the Rebreather –
In the Water
FIRST IMPRESSIONS IN THE WATER
• Silence
• Bubble-free
• Listen for the solenoid firing
• Check PPO2 on the handsets every minute
• Dynamic bouyancy change caused by computercontrolled oxygen
• Unit is bouyant at shoulder level due to air volume in
counterlungs and hoses
• Add weight at the top for trim
• Remember – no matter how experienced you are on OC,
you are now a beginner again
Let’s Go Diving the Rebreather –
In the Water
EARLY TECHNIQUE POINTERS
• Do not expect to get it right first time
• Try to keep the loop volume at a minimum for comfort
• Keep a steady depth level
• Try to maintain a horizontal, neutral bouyancy, attitude
while swimming
• Use vertical attitude only when testing skills under
instructor guidance
• Be generous with weighting (1 or 2kg over)
Let’s Go Diving the Rebreather –
In the Water
BASIC WATER SKILLS DEVELOPMENT
• Mouthpiece opening and closing techniques
• Open Circuit bail-out to Auto-Air
• Diluent flushes and checking PPO2 drop
• Check diluent flush predictions
• Bouyancy normalisation while swimming
• Constant checking of PPO2 on handsets
• Understanding and reacting to alarm conditions
(mostly simulated while on course)
• Loop volume control
Let’s Go Diving the Rebreather –
In the Water
BAD – DAS DRILLS
• In the event of in-water problems, rely on
BAD-DAS drills
– B Bail-out to open circuit
– A Anxiety breaths (3)
– D Decide what to do
• If returning to the loop, then:
– D Diluent flush – breathe fresh gas
– A Always know your PPO2 – check handsets
– S Skills. Apply appropriate skills gained
during training to overcome the problem
Let’s Go Diving the Rebreather –
In the Water
LOW O2 DRILLS
• Manual flight
– 1 Using O2 inflator
– 2 Adding oxygen using O2 tank valve
– 3 Using machine in semi-closed circuit mode
• Low oxygen danger
– 1 Solenoid stuck closed
– 2 O2 tank empty or switched off
• Handset failure or switched off
– If both are blank, go open circuit or if gas
volumes dictate, switch to semi-closed
circuit mode
Let’s Go Diving the Rebreather –
In the Water
HIGH OXYGEN DRILLS
• Open circuit bailout
• Use of diluent flush to drop PPO2
• Closing oxygen tank if solenoid fails open
Let’s Go Diving the Rebreather –
In the Water
MENU MODE DRILLS
• Sequencing through menu commands in water
to become familiar with functionality
• Changing Setpoints
• Changing from one controller to the other
• NEVER CALIBRATE UNDER WATER
Let’s Go Diving the Rebreather –
In the Water
HYPERCAPNIA DRILLS
• Open Circuit Bailout
• Diluent flushes
• Practice/Practice/Practice
Let’s Go Diving the Rebreather –
In the Water
ELECTRONICS MALFUNCTIONS
• Handset and controller problems
• Cell errors or missing cells
• Intermittent alarms
• Poor PPO2 tracking to setpoint
• Possible Loop Floods
TDI Inspiration/Evolution Family
of Rebreathers Divers Course
Section 9:
Avoiding Rebreather Incidents
– Safe Diving
Avoiding Rebreather incidents –
Safe Diving
All the training in the world is useless if you
do not adopt the following as your
personal mantra for CCR Diving:
– Safe Attitude
– Safe and enhanced Awareness
– Safe and structured Discipline
Avoiding Rebreather incidents –
Safe Diving
OPERATIONAL MAINTENANCE
• Check battery connections are clean and dry
• Ensure handsets are cleaned in fresh water,
particularly Classic handsets with spring-loaded
Hall-Effect slide switches
• Keep O-rings well cleaned and lubricated to
prevent abrasion and other damage
Avoiding Rebreather incidents –
Safe Diving
REMEMBER DURING PRE-DIVE PREPARATION
• Properly assemble and check according to a
check list
• Do not get distracted during calibration
• Do all the pre-dive checks and then “go live”
for a short “dry-dive” to pre-breathe prior to
entering water in order to ensure dynamic
functionality of the machine
Avoiding Rebreather incidents –
Safe Diving
DIVE PLANNING
• Break dive into logical “waypoints” to do
checks and flushes for safety
• Usual waypoints
_ 6msw (20fsw) bubble leak check
– On descent - switch to high setpoints
– On reaching bottom - diluent flush and
check guages and handsets
– After pre-set time or leaving bottom diluent flush
– On ascent (10msw or less) - gas venting to
control bouyancy
Avoiding Rebreather incidents –
Safe Diving
REMEMBER ON THE DESCENT
• Do a shallow (6msw/20fsw) bubble check
• Descend slowly to control breathing loop volume
• Watch the PPO2
• Switch to high setpoint according to plan
Avoiding Rebreather incidents –
Safe Diving
REMEMBER ON THE ASCENT
• PPO2 will drop, solenoid should fire, and oxygen
should come into the loop quickly – rapid
bouyancy increase
• Check PPO2 closely on ascent to reduce
Hypoxic risk if there is insufficient O2 in the loop
• Carefully control ascent rate
• 3 potential bouyancy devices – drysuit, wing and
loop counterlungs
Avoiding Rebreather incidents –
Safe Diving
REMEMBER AT THE SURFACE
• NEVER switch off the handsets or tanks at the
surface above deep water
• Only shut down after equipment has been taken off
• You still need to watch your PPO2 if you breathe on
the loop at the surface
• It’s the best snorkel you ever bought!!!
Avoiding Rebreather incidents –
Safe Diving
REMEMBER AFTER THE DIVE
• Gas up again for the following dive
• Check and replace batteries/scrubber
as necessary
• Disinfect and clean as necessary
• Conduct all other system checks to ensure
correct functionality of cells and handsets
• Log your dives
Avoiding Rebreather incidents –
Safe Diving
TDI Training and Manufacturers Manuals
– Errors and troubleshooting are well documented
for reference
– Maintain your own service log for
batteries/scrubber and other service needs
– There is an “elapsed On Time” log kept on the
controller until reset under menu control
– Document your rebreather experiences