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TDI Evolution Closed Circuit Rebreather Diver Course by BorneoDream.com Billy Hammond #10407 - 2007.

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Presentation on theme: "TDI Evolution Closed Circuit Rebreather Diver Course by BorneoDream.com Billy Hammond #10407 - 2007."— Presentation transcript:

1 TDI Evolution Closed Circuit Rebreather Diver Course by BorneoDream.com Billy Hammond #

2 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

3 7 - Lets Go Diving the Rebreather - Preparation 8 - Lets 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) Overview of Course Structure continued TDI Inspiration and Evolution Closed Circuit Rebreather Diver Course

4 TDI Inspiration/Evolution Family of Rebreathers Divers Course Section 1: Introduction and Welcome

5 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

6 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

7 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 PPO 2 setpoint –Warm and moist comfortable breathing gas reducing risk of hypothermic tendencies

8 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

9 TDI Inspiration/Evolution Family of Rebreathers Divers Course Section 2: The History and Development of Rebreathers

10 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

11 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 CCRs with the Inspiration in 1997, followed by Prism, Megalodon, Ouroboros, Optima and Kiss, and in 2005 the Evolution

12 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

13 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

14 TDI Inspiration/Evolution Family of Rebreathers Divers Course Section 3: Mechanics and basic functioning of the Inspiration and Evolution rebreather systems

15 Mechanics and basic functioning of the Inspiration and Evolution Divers 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

16 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

17 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 O 2 rich gas to the body and CO 2 rich gas from the body When we inhale, clean O 2 rich gas comes in from the left. The flow is from the divers lungs through the mouthpiece to the right

18 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 divers breathing pattern. Hoses are large bore. This reduces the work of breathing (WOB) Mouthpiece hose is weighted for dynamic balance - adjustable

19 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

20 Mechanics and basic functioning of the Inspiration and Evolution THE CO 2 SCRUBBER (or Stack) Gas path is from the exhalation counterlung, through the T-piece down to the bottom of the CO 2 scrubber It fans out to a large bore axial flow through the scrubber to reduce gas velocity and increase Dwell Time for CO 2 removal

21 Mechanics and basic functioning of the Inspiration and Evolution THE SCRUBBER CARTRIDGE Designed to remove CO 2 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

22 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 CO 2, not any other toxic compounds or contaminants in the breathing gas

23 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

24 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 CO 2 and grows mold

25 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

26 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

27 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

28 THE SCRUBBER LID and HANDSETS The electronic brains of the device Function is to control the PPO 2 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

29 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 PPO 2 values Delicate pin connections Should never smell of toxic or other vapors Mechanics and basic functioning of the Inspiration and Evolution

30 THE HANDSETS ( and HUD on Vision) Redundant controller PPO 2 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 PPO 2 on the handset

31 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 PPO 2 on the handset during the dive Mechanics and basic functioning of the Inspiration and Evolution

32 CONSTANT PPO2 GAS CONTROL Remember Daltons Law from Advanced Nitrox Pressure gas = FO 2 x Pressure At different depths (gas pressures) for a constant PPO 2 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 PPO 2 setting Mechanics and basic functioning of the Inspiration and Evolution

33

34 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

35 WARNING BUZZER (and HUD) Connected to the scrubber lid but normally fed to the T- piece by divers 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

36 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

37 THE OXYGEN SUPPLY Dive tank switched on HP to SPG on front of exhalation lung gives O 2 pressure LP hose feeds O 2 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

38 INHALATION COUNTERLUNG O 2 rich gas from the scrubber lid comes up to the inhalation counterlung Blue color coded for hoses containing clean oxygenated gas with the CO 2 removed Passes through the inhalation T-piece without Water-Traps on the newer machines Blue Manual Diluent addition button at bottom of inhalation counterlung

39 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

40 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

41 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 2 nd stage regulator connected directly to the diluent gas supply via the first stage regulator The wing can be fitted with an optional crack- bottle for alternate gas source inflation Mechanics and basic functioning of the Inspiration and Evolution

42 Section 4: Classic Electronics Control TDI Inspiration/Evolution Family of Rebreathers Divers Course

43 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

44 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 PPO 2 Classic Electronics Control

45 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 Classic Electronics Control

46 TDI Inspiration/Evolution Family of Rebreathers Divers Course Section 5: Vision Electronics Control

47 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

48 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

49 Vision Electronics Control SINGLE HUD DEVICE Dual redundant displays of twin LEDs one green one red connected to C1 and C2 Fiber optic cable running along mouthpiece hose connects to controllers in Scrubber Lid Green LEDs are Good Red LEDs 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

50 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 CO 2 monitor Temp Stick is a temperature sensing system to detect where the main Burn Face of CO 2 absorption is taking place through the scrubber segments It aids in scrubber maintenance monitoring

51 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 PPO 2 readings for the 3 cells are displayed across the middle of the LCD

52 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

53 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.

54 Vision Electronics Control Calibration –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 O 2 valve, diluent valve, and system bailout

55 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

56 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

57 TDI Inspiration/Evolution Family of Rebreathers Divers Course Section 6: Physiology – A Reflection for the CCR Diver

58 Physiology – A Reflection for the CCR Diver BASIC PREMISE We need to breathe clean (CO 2 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 PPO 2 selected by the diver

59 ADDITIONAL CONCEPTS The low and high PPO 2 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

60 CO 2 and HYPERCAPNIA Humans consume O 2 at a cellular level and generate CO 2 as a waste product Blood transports O 2 to the cells and removes CO 2 Blood exchanges CO 2 for O 2 at the lung Alveoli The urge to breathe is driven by the level of CO 2 retained in the body (blood and cells) With hypercapnia and elevated CO 2 levels, the breathing rate is increased (panting – dypsnea) to try to vent the lungs and alveoli Physiology – A Reflection for the CCR Diver

61 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 doesnt 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

62 RE-INHALATION OF CO 2 CO 2 normally removed by Sofnolime scrubber Conditions when this doesnt occur properly –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 CO 2 content in the breathing loop –Incorrect scrubber packing Physiology – A Reflection for the CCR Diver

63 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 CO 2 across its surface decreases Physiology – A Reflection for the CCR Diver

64 HYPEROXIA Too much oxygen results in O 2 toxicity risk Inspiration/Evolution alarm is set at a PPO2 of 1.6 or above Track O 2 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 OTUs carefully on multi-dive days or multiple repeat dive days Physiology – A Reflection for the CCR Diver

65 SYMPTOMS OF HYPEROXIA CONVENTID –CONConvulsions –VVisual disturbances/Tunnel vision –EEars ringing (Tinnitus) –NNausea –TTingling or twitching (facial) –IIrritability –DDizziness or vertigo Physiology – A Reflection for the CCR Diver

66 PULMONARY TOXICITY O 2 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 PPO 2 of 0.5 thus very real danger for CCR and Inspiration/Evolution diving Physiology – A Reflection for the CCR Diver

67 HYPOXIA Occurs if the PPO 2 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

68 CNS TOXICITY AND OTUs Real danger of convulsing and drowning if your CNS is not monitored properly Always know the PPO 2 in the loop and do a diluent flush to check any odd readings Track your CNS % and OTUs on the NOAA tables in your manuals Physiology – A Reflection for the CCR Diver

69 ASPHYXIA Like strangulation it is caused by a shortage of oxygen and buildup of CO 2 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 Physiology – A Reflection for the CCR Diver

70 TDI Inspiration/Evolution Family of Rebreathers Divers Course Section 7: Lets Go Dive the Rebreather - Preparation

71 Lets 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

72 Pay particular attention to the following during assembly and inspection; Positive & negative pressure tests Cylinder contents analysis Cylinder pressure on SPGs HUD LEDs functioning (if HUD used) Alarm working audibly Listen for solenoid firing and alarm sounding when handsets switched on Switches on handsets working normally Mushroom valve checks on the mouthpiece assembly Lets Go Diving the Rebreather - Preparation Wing and Auto-Air checks Scrubber packing, O-ring and spacer functioning Hose O-ring lubrication Battery power levels

73 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 Lets Go Diving the Rebreather - Preparation

74 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 Lets Go Diving the Rebreather - Preparation

75 Calibration of O 2 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 Lets Go Diving the Rebreather - Preparation

76 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 O 2 value, diluent value bailout Lets Go Diving the Rebreather - Preparation

77 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 Lets Go Diving the Rebreather - Preparation

78 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 Lets Go Diving the Rebreather - Preparation

79 Dry dive simulations (approx 30 minutes) These provide useful simulations in a safe environment for learning and troubleshooting Lets Go Diving the Rebreather - Preparation

80 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 Lets Go Diving the Rebreather - Preparation

81 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 Lets Go Diving the Rebreather - Preparation

82 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 Lets Go Diving the Rebreather - Preparation

83 GENTLE EXERCISE Walk about with the rebreather on Simulate moderate exercise Notice breathing, rate increases, and solenoid firing more often than when at rest. Lets Go Diving the Rebreather - Preparation

84 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 PPO 2 tracking, hear solenoid firing and notice little or no change in loop volume The student should still feel fine and have no CO 2 problems Lets Go Diving the Rebreather - Preparation

85 LOW ALARM CHECK Sit, relax and come off the machine – breathe normal air Blow air into the loop to drop the PPO 2 below 0.4 Check for alarms and observe PPO 2 coming back to setpoint again under automatic computer control Lets Go Diving the Rebreather - Preparation

86 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 PPO 2 back to setpoint Switch handset or controller C1 back on again Lets Go Diving the Rebreather - Preparation

87 SETPOINT CHANGES Switch to High and then back to the Low Setpoint when the PPO 2 rises to 0.9 and observe PPO 2 on handset Test how long it takes to breathe the loop back down to a PPO 2 of 0.5 at rest Lets Go Diving the Rebreather - Preparation

88 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 O 2 is injected to bring PPO 2 back up to setpoint because of the air you introduce to the loop Alarm for Low PPO 2 may also sound when returning to loop and filling it with air Lets Go Diving the Rebreather - Preparation

89 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 PPO 2. Listen to solenoid firing. It is possible that the PPO 2 may drop below 0.4 and cause an alarm Lets Go Diving the Rebreather - Preparation

90 MANUAL GAS ADDITION Give a small squirt of O 2 with the manual addition button and observe the PPO 2 reading Repeat the exercise with diluent Repeat to get a feel for the addition buttons Lets Go Diving the Rebreather - Preparation

91 TDI Inspiration/Evolution Family of Rebreathers Divers Course Section 8: Lets Go Dive the Rebreather – In the Water

92 Lets Go Diving the Rebreather – In the Water Rule No 1 If in doubt – bail out! Rule no 2 If something feels wrong – it is!

93 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 Lets Go Diving the Rebreather – In the Water

94 FIRST IMPRESSIONS IN THE WATER Silence Bubble-free Listen for the solenoid firing Check PPO 2 on the handsets every minute Dynamic bouyancy change caused by computer- controlled 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 Lets Go Diving the Rebreather – In the Water

95 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) Lets Go Diving the Rebreather – In the Water

96 BASIC WATER SKILLS DEVELOPMENT Mouthpiece opening and closing techniques Open Circuit bail-out to Auto-Air Diluent flushes and checking PPO 2 drop Check diluent flush predictions Bouyancy normalisation while swimming Constant checking of PPO 2 on handsets Understanding and reacting to alarm conditions (mostly simulated while on course) Loop volume control Lets Go Diving the Rebreather – In the Water

97 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 PPO 2 – check handsets –S Skills. Apply appropriate skills gained during training to overcome the problem Lets Go Diving the Rebreather – In the Water

98 LOW O 2 DRILLS Manual flight –1 Using O 2 inflator –2 Adding oxygen using O 2 tank valve –3 Using machine in semi-closed circuit mode Low oxygen danger –1 Solenoid stuck closed –2 O 2 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 Lets Go Diving the Rebreather – In the Water

99 HIGH OXYGEN DRILLS Open circuit bailout Use of diluent flush to drop PPO2 Closing oxygen tank if solenoid fails open Lets Go Diving the Rebreather – In the Water

100 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 Lets Go Diving the Rebreather – In the Water

101 HYPERCAPNIA DRILLS Open Circuit Bailout Diluent flushes Practice/Practice/Practice Lets Go Diving the Rebreather – In the Water

102 ELECTRONICS MALFUNCTIONS Handset and controller problems Cell errors or missing cells Intermittent alarms Poor PPO2 tracking to setpoint Possible Loop Floods Lets Go Diving the Rebreather – In the Water

103 TDI Inspiration/Evolution Family of Rebreathers Divers Course Section 9: Avoiding Rebreather Incidents – Safe Diving

104 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

105 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

106 Avoiding Rebreather incidents – Safe Diving 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 REMEMBER DURING PRE-DIVE PREPARATION

107 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

108 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 PPO 2 Switch to high setpoint according to plan

109 Avoiding Rebreather incidents – Safe Diving REMEMBER ON THE ASCENT PPO 2 will drop, solenoid should fire, and oxygen should come into the loop quickly – rapid bouyancy increase Check PPO 2 closely on ascent to reduce Hypoxic risk if there is insufficient O 2 in the loop Carefully control ascent rate 3 potential bouyancy devices – drysuit, wing and loop counterlungs

110 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 PPO 2 if you breathe on the loop at the surface Its the best snorkel you ever bought!!!

111 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

112 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


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