LOGORebreather TR300

WARNING: Rebreather diving is different. The use of this Rebreather is at your own risk. Rebreathers may kill you.

The possibilities of diving with an rebreather offers some great features. On the one hand there are the long divingtimes because of low usage of oxygen and diluent, on the other hand the silentness. I was interressted since middle of the last year in rebreathers. I read the most out of the web.

Now I want to build my own rebreather.

The major focus for me was: very reasonable, easy, reliable and extensible.

Inspired from other constructions and also from the Submatix was my Idee to build just the major part of the rebreather (scrubber container, breathingbag, gasaddition system, fitting). First stages and cylinder own the most divers allready.

Another focus was to flexible configure the Rebreather in case of Divetime and bailout. (Scrubbervolume and gas).

The solution is the TR 300.

The design based on:

  • For the first I have a scrubber size from 2.5 kg. Extensible scrubber canister The rebreather consist out of a simple scrubber canister. The size of the scrubber canister can be changed. All you need is to connect a longer out and inner cylinder and screw between the top and bottom plate.
  • oxygen meassure. The top plate has all the opening for the inhale and exhale connectors, also for the oxygen sensors and electrical connectors. For SCR Modus is it only necessary to Monitor the oxygen, the sensors can alternativ connect to a divecomputer e.g. VR3.
  • gasaddition. The diluent will be added through a “automated diluent addition valve” (is like a SCUBA second stage). In the same housing there is also the oxygen addition connected so both gases will be mixed before they will be inhale through the scrubber. The mixed Gas flow comes through an needlevalve. For better gasmanagement there is now a switchblock available.
  • Breathingbags near by the divers lung (on the back). This point must be changed. The counterlung ist now under the scrubber canister. It is only one bag with maximum of 7 litres volume. The counterlung is in the lower part of the protecting outer tube. The exhaust area goes still through the scrubber cylinder into the counterlung, the breathingbag now holds some amount of water (condensat and seawater) so we have a perfect watertrap. The air can then go back by the second counterlung connector.
  • Changable, stable and save construction. The inner part (scrubber canister and counterlung) is inside a outer tube and can be pulled out.
  • Using of standard breathing gas cylinders. At the outer protection tube will the gas cylinders be fit. It is possible to fit them “upside down” so you can reached the cylindershutdownvalve in a better position. It can be fit cylinders from 2 liter upto 10 liter.
I think a good combination will be: a 2 to 4 Liter cylinder for oxygen and at minimum a 4 Liter cylinder for bailout, bottommix and BC. I have also tested it up to 10 liters ! on both side (yes then it will be run heavy 🙂 )

SCR mode with two different mixes and switchblock

cylinder mainmix TZ MM TUMS bottommix TZ BM TT
4 litres 80% 4 l/min

60% 5 l/min

40% 10 l/min

160 min

128 min

64 min

10 msw

21 msw

30 msw

40% 4 l/min

32%* 5 l/min

21%* 10 l/min

160 min

128 min

64 min

25 msw

34 msw

57 msw

5 litres 80% 4 l/min

60% 5 l/min

40% 10 l/min

200 min

160 min

80 min

10 msw

21 msw

30 msw

40% 4 l/min

32%* 5 l/min

21%* 10 l/min

200 min

160 min

80 min

25 msw

34 msw

57 msw

Bailout 40bar left / Mainmix 40bar left

gasconsumption without bailout !

TZ MM = Divetime mainmix

TUMS = Depth switching mainmix – bottommix

TZ BM = Divetime bottommix

TT = MOD (max.)

* = Bottommix not breathable in shallow water !

Drawing of the TR300.

The outer cylinder is now 70cm in high and has a diameter from 16cm, so we have a counterlung volume from approx. 5.5 liter and a srubber volume from approx. 2.5 liter

You can get the TR300 “tubes” as a “self-assembly” kit (the most parts are ready made) from contact or eShop

The unit has no CE marking and is possible to buy for exhibition purposes.

TR300 shematic
Drawing of the scrubber top plate. The plate is made from PVC 2cm thick an has the openings to fit the in-/exhale screwings. The PVC plate is sealed with a double O-ring on the outerside.

The smaller holes are for the screws and for some electrical.(e.g. oxygen sensor)

TR300 Deckel
Function of the TR300 with mono (1) Gas.

Function:

The exhale Gas goes from the mouthpiece through the hoses to the TR300. The exhale is “falling” down through a pipe into the counterlung (this ist the reliable watertrap).

After them the CO2 enriched breathingair goes through the scrubber and the CO2 will be washed out.

In the head of the scrubbercanister the O2 poor breathinggas will be added with fresh gas from the Bypass or constant flow and the can be breathed again.

The constant flow can be switched on and off at the switchblock

The bypass is fix connected to the regulator (1.stage).

green: inhale side with high O2

red: exhale side with high CO2

TR300 shematic single
Function of the TR300 with dual (2) Gas.

Function:

The exhale Gas goes from the mouthpiece through the hoses to the TR300. The exhale is “falling” down through a pipe into the counterlung (this ist the reliable watertrap).

After them the CO2 enriched breathingair goes through the scrubber and the CO2 will be washed out.

In the head of the scrubbercanister the O2 poor breathinggas will be added with fresh gas from the Bypass or constant flow and the can be breathed again.

The bypass and the constant flow can be switched to a low bottom gas or a high dekogas.

green: inhale side with high O2

red: exhale side with high CO2

The head of the TR300 has a redesign.

For a better laying of the breathing tube I use now 90 degree fittings.

The whole gas injection is now integrated direct in the head, here you see the bypass and gasinjection.

TR300 Kopf
the stainless Steel Gasswitchblock with two inlets and one outlet to the ADV and one outlet with regulated flow (neadlevalve) to the gasinjection. Switchblock
The scrubber filters made from stainless steel.

On the upper filter, you can see the distansscreews for the O2-Sensor and the inner inhale volume of the scrubbercanister

The outer part of the filters is protected with rubber

TR300 Sieb
The whole scrubber inlet

The long screew in the middle is for pressing the scrubber between the two plates

TR300 Filter
The whole scrubbercylinder.

The cylinder is 25cm in hight and has a inner diameter from 144mm.

For better isolation against cold water is a neoprensuit used.

TR300 scrubber
All parts of the TR300.

you see (from top to bottom):

  • Scrubbercanister (2.2 kg) with counterlung (6 Liter)
  • Needlevalve (SCR-Mode) and lowpressurehose and bypass
  • Breathinghose with mouthpiece
TR300 parts
The TR300 V2 ready made on a Dive System Wing and Jacket.

The housing (60cm) is silver pained.

Good to see, the cylindes has now enough place on top of the housing

If we use larger cylinders than 4 Liter, the it will be better to place them with valve “up”.

The TR 300 mounted on a “dive system” wing and backplate. On the picture I am ready to dive with Gerd, but I have to less weight with me. The lower laying counterlung is pulling a little bit. TR300 dive ready
The TR300 now under water. Here you see very well the exhausted gas comes out of the middle of the TR300. TR300 under water single cylinder