Inspiration Features

The Inspiration is the first CE approved Closed Circuit Rebreather and has spent many hours being tested by DERA (military testing establishment) which it passed very satisfactorily. These tests included breathing resistance, scrubber durability, quality and fitness as life support equipment.

 

Inspiration Features
Good Features
Bad Features
Martin Parker's reply

 

The Inspirations features include

Diver Moles Good features

Diver Moles Bad features (see Martin Parker's reply to this below)

 

Martin's Reply

Despite a busy and hectic schedule trying to build new Turtles and answer emails from all us owners, Martin Parker has kindly taken the time to go through the Bad features with me. I have copied his e-mail in full below. Thanks for the feedback Martin

 
  • Handsets are not truly independent, they share calibration data (I removed this after seeing the reply)
    •  They don't share calibration data at all. Each handset has its own calibration factors stored for each cell.
     
    The link between the handsets allows the Master's PO2 to be read by the Slave for it to calculate its own calibration factors based on its own readings from the cells.
    Once those factors are stored then there is no further data transfer between the cells except for setpoint and timer information. (The Master's PO2 is the PO2 you told it by entering eg 1000mbar and 99%O2 = 0.99)
     
    The original units had exposed connections in the handsets. They haven't since June 1978 and they've all been modified. The common link between the handsets is through the O2 cells. So if you get a short at one handset (which is now practically impossible) the fault will show through the cell to the other handset as well. If you get the short at the cell, then it will show on both handsets. - But this is the same for every unit thats ever been devised.
     
  • Batteries are in the same box and hence can flood at same time. 
    • On the other hand, if they flood its no big deal, with Lithium batteries. If you get that much water in, you know about it first hand - as it's hard to breathe through the scrubber with that much water in it. It saves making the battery box pressure proof. These batteries are low discharge when shorted. Full short under load for four hours in salt water - tiny harmless, bubbles start to appear. Try shorting out NiMH or lead acid batteries then I agree the location in the lid would be a problem.
     
  • There are issues with battery connections if the unit is shaken in the right way
    • More particularly, the unit works best with Energizer batteries. Different makes vary in dimensions and capacity.
     
  • O2 cells can collect condensation and affect readings
    • Condensation on the front face of the cell just doesn't affect the readings. This problem existed with the old cells pre 1999 or so when we retained the gold mesh in front. Now you can flood the front face entirely, tip off the excess and the response time is the same.
     
  • Unit may be dived switched off. No auto switch on
    • Both Draeger and us have shied away from auto-switch on. If they just jump in - there's no calibration. Divers don't have auto switch on tank valves either. Is it really unrealistic to expect the diver to take some responsibility for this ?
     
  • Early units may be calibrated underwater (not a life sustaining action)
    • Yes, if the diver does a lot of stupid things. We have only had this happen once and that was with a non-trained user getting his hands on one. To calibrate underwater, you had to switch both handsets off (quite why you would want to do that?) then on switch on, you are prompted Calibrate (or MUST calibrate) YES or NO which if you were underwater you would answer NO to but he didn't, then when he was asked for ambient pressure he entered 1000mbar, where in fact his ambient pressure was 6000 mbar! So the unit flushed the loop with pure O2 at 50m. Because he entered 100% O2 at 1000 mbar the unit displays 1.0 bar PO2 - because that's what he told the machine was his PO2. In fact of course it was 6.0 bar. Then he tries to change to the high setpoint of 1.3 bar, whereas in fact it was trying to reach 6.3 bar. It can't reach 6.3 bar in 50m of water, so the O2 solenoid was working overtime adding lots of gas, giving him a loop volume problem and a buoyancy control problem. Despite this, he kept going for 20 mins before he had two O2 convulsions, both of which he survived!
     
    The later units were changed to reject rogue cells of high or low output during calibration. This also rejected the attempt at calibration if the diver was at depth.
     
  • Handsets are vulnerable to damage and physically large
    • Yes, they don't take too kindly to having the rebreathers bounce on them but the new ones are tougher now.

     

  • Voting logic can be fooled by 2 cell problems at once
    • If you get two cells, current limited (usually because they haven't been replaced in 2 years of diving) and they display a very steady PO2 of just below 1.3 bar, these two will be assumed to be the correct cells by all known voting methods - so this problem isn't specific to the Inspiration.
    The Inspiration has an excellent catch all known as the "cell warning" which will still provide the diver with a warning in this instance.
     
    Harness is too engulfing and holds too much water after diving.
    Too engulfing? Two shoulder straps and a waist band ? - that's cobblers
    Holds too much water? - okay, being fabric it takes some drying out. Most of the water retention though is draining out of the wing and in the soft comfort pad in back section. Take the soft pad out if you don't want it - it's velcroed in.
     
  • Hose is heavy out of water while pre-breathing and post dive 
    • - beautifully balanced in the water though.
     
  • Units case is not flexible in allowing different size cylinders to be fitted
    • - your inexperience is showing through here. So many when they first start, think they need bigger cylinders. Live with it for now, put side mounts on if you really feel you have to until you prove to yourself that you don't need cylinders as big as 3 litres!

    (No, I'm an air guzzler and need an extra 6 litres of air to safely bail out of most 40-50m dives. I'd rather have this as a single 7L built in the unit than carrying stages. I currently dive ALWAYS with an extra 3 litre mounted on the case, and carry and extra 3 or 7 L 50% side slung for longer dives. The single 3L is just enough (very just) to get me to the surface from 40m, It does not hold enough for me to do any deco. Some of us older and unfitter divers just don't have the low SAC we used to have, and add some apprehension into the equation)

      
  • No Auto Diluent Addition on descent
    • Ours is coming. Its been 18 months in development. The last pre-production run revealed a problem with the diaphragm so that mould is being modified prior to the next pre-production run and then production. When it comes out it will be third part tested and CE approved.
     
  • O2 sensors are expensive and need replacing yearly.
    • They should be more expensive than they are, and the normal changeover is at 18 months. Some reduce this to 12 months but this is purely a personal matter.  If you stored the cells in a high O2 environment, you'd have to replace them every 3 months or so.
     
  • Some people cannot hear the audible warnings
    • I find that unbelievable. I haven't had a comment about anyone not hearing the buzzer for more than 4 years.
     
     
    Okay, time's running short now. I'll call it a day at that.
     
    all the best
     
    Martin
     
    Martin Parker
    Managing Director
    Ambient Pressure Diving
    Manufacturers of the Inspiration Closed Circuit Rebreather
    Water-ma-Trout Industrial Estate, Helston, Cornwall, TR13 OLW, UK.
    Tel: 01326 563834, Fax: 01326 573605.
    Website: www.ambientpressurediving.com