MixterT: continous Trimix mixer [OLD version 2005]

 

After a long seek of informations on Internet, asking to divers and receiving too many little good answers, we have tryed to resolve several problems without tecnical knowledges, but only moving and changing every piece of the system. Maybe it is not the perfect way to build a continous trimix mixer, of course we'll still modify the project, potential problems are ever present and obviously, this system is for personal use. We load normaly 20000lt of gas per a day, but the time for loading these liters it depends from the power of your compressor.

A continous mixer it's not difficult to build, if you don't complicate your way like I just see from other divers. First thing to have, it's a diving compressor, the item that costs more of all the project. With 1000Euro you can find an used 100-80lt/min, that for personal use it is enough.With a normal 3Kw system electrical or a small petrol engine compressor you can load your tanks with Air, Nitrox, Trimix.

A generic schema of the system project [click here]

The project needs of:

  • diving compressor
  • pressure reducer for oxygen INPUT 200bar OUTPUT at least 1,5/15 bar
  • pressure reducer for helium INPUT 200bar OUTPUT at least 1,5/15bar
  • transfer hose for oxygen compatible and manometer 200 or 300bar at least 200cm of length
  • flow regulatore to use for oxygen loading
  • personal or diving filter for compressor output
  • air filter for car engine or similar
  • hydraulic and PVC tubes of several dimensions and length, adapters and glue
  • HE analyzer (only if you want be sure of your mix or check on local dive site)
  • Oxygen analyzer
  • a set of helium/oxygen industrial tanks. Check what kind of gas you are loading: industrial, medical, etc.
    OXYGEN it's a very dangerous gas when compressed, it can explode
    HELIUM it's asfisiante
    Check what you are doing, we are not responsible of what you do

The system can be builded with hydraulic, PVC, electrical tubes or what you want, only thinf that is important it's that joints must be secure and without losses. First thing it's to build the mixer for Nitrox, after you can build at the same way the mixer for the Trimix. Of course you can use an unique mixer, we wanted to load independently the gases. The mixer it's composed by a cone of tubes, with the oxygen input, an air filter of a car inside, that filters air aspired from the compressor from the holes. You can insert some pieces of PVC with holes to create turbolences and better mixer the gas.

Pressure reducer and a flow regulator must be used to transfer Oxygen from tanks to your first mixer. You can regulate the percentual you need. Be sure of not exceed loads of 40% oxygen in the compressor. It's very dangerous and can explode.
At the output of the mixer you can insert an oxygen analyzer to check your % of loading. After you can load directly the compressor with Nitrox mix.
A personal filter can be added in output of your compressor to be sure of load oil-free gas in your tanks.
An other mixer can be build to mix Nitrox with Helium. In this case the mixer don't need a filter inside, but we must be sure that it's dry, because losses at this moment can deform the Trimix you want. Two input mixer, one for the output nitrox mixer and one for helium flow regulator. In the output you can add an helium analyzer to check the load.

 
After a loading you must ever check the final gas mix, to be sure of you'll breath underwater


ATOMIK & FOX