I always thought it was only for real emergencies - IE the air intake filter/line somehow becomes entirely blocked - to ensure the compressor won't run itself dry of air.
Recently i have begun to continuously blend extra O2 through our little MCH-6. We noticed an alarming difference between the pre-compressor O2 levels, and after running through the machine, the condenser, filters, etc to the whip.
If the O2 reading is say 30% pre compressor, the resulting mix will be around 26 - 27%. 35% will be 30% If it is 40%, 32-33%. Almost a sliding scale.
So i ran the compressor at varying pressures to check it, analyzing before, and placing another sensor at the end of the whip. I have checked and calibrated both analyzers on the same mixes of between 21 and 100%. They are both fine and read the same for any given O2 value.
The same difference was shown at all pressures. A major loss of O2.
Where did the O2 go? Maybe a little can be taken by the condensed water, but up to 7%?
Then i covered the hole, which i think of as the relief valve. It is located just after the air inlet filter housing point, sitting in the first piston head cover area. See the attached pics.
When i covered this with a finger, the O2 levels would then read exactly the same on both analyzers.
So, is my inlet pipe restricting the flow of gases into the compressor? Maybe. At no point is the line smaller than the final entry to the compressor. In fact it is probably 50% larger, up to when it enters the air filter housing.
The thought is that the combination of my stick, piping etc may cause a decrease in air availability to the compressor, and thus it sucks in extra air (21%) to compensate, decreasing the potency of my mix.
The mix suffers and i waste O2. BUT the worst thing is that the air going into the compressor is unfiltered!
I went and checked another MCH-6, the same but a petrol model and a little older. Same hole, acted the same when the air inlet flow was blocked, relieving the compressor and supplying air through it.
That's all fine. What i am wondering is if, say we are running just air through the machine, maybe even take out any piping that is used to mix the air and O2, will this little valve be sucking in "dirty" air to the first piston? Even just a little bit?
When i am running the extra O2 through the compressor, the valve always feels like it is just pushing out extra mix from the cylinder, not sucking anything in. Exactly the way it feels when it is running air. But if that was the case, the mix % would stay the same. It MUST have an air entry somewhere. Maybe it's to do with the stick and piping. But maybe it's not?
Is there any way to check that even with normal air, with no long pipes or baffled sticks to deal with, there is no bad air leak into the compressor?
Alot of jumbled info i know. And a few questions, queries.
Recently i have begun to continuously blend extra O2 through our little MCH-6. We noticed an alarming difference between the pre-compressor O2 levels, and after running through the machine, the condenser, filters, etc to the whip.
If the O2 reading is say 30% pre compressor, the resulting mix will be around 26 - 27%. 35% will be 30% If it is 40%, 32-33%. Almost a sliding scale.
So i ran the compressor at varying pressures to check it, analyzing before, and placing another sensor at the end of the whip. I have checked and calibrated both analyzers on the same mixes of between 21 and 100%. They are both fine and read the same for any given O2 value.
The same difference was shown at all pressures. A major loss of O2.
Where did the O2 go? Maybe a little can be taken by the condensed water, but up to 7%?
Then i covered the hole, which i think of as the relief valve. It is located just after the air inlet filter housing point, sitting in the first piston head cover area. See the attached pics.
When i covered this with a finger, the O2 levels would then read exactly the same on both analyzers.
So, is my inlet pipe restricting the flow of gases into the compressor? Maybe. At no point is the line smaller than the final entry to the compressor. In fact it is probably 50% larger, up to when it enters the air filter housing.
The thought is that the combination of my stick, piping etc may cause a decrease in air availability to the compressor, and thus it sucks in extra air (21%) to compensate, decreasing the potency of my mix.
The mix suffers and i waste O2. BUT the worst thing is that the air going into the compressor is unfiltered!
I went and checked another MCH-6, the same but a petrol model and a little older. Same hole, acted the same when the air inlet flow was blocked, relieving the compressor and supplying air through it.
That's all fine. What i am wondering is if, say we are running just air through the machine, maybe even take out any piping that is used to mix the air and O2, will this little valve be sucking in "dirty" air to the first piston? Even just a little bit?
When i am running the extra O2 through the compressor, the valve always feels like it is just pushing out extra mix from the cylinder, not sucking anything in. Exactly the way it feels when it is running air. But if that was the case, the mix % would stay the same. It MUST have an air entry somewhere. Maybe it's to do with the stick and piping. But maybe it's not?
Is there any way to check that even with normal air, with no long pipes or baffled sticks to deal with, there is no bad air leak into the compressor?
Alot of jumbled info i know. And a few questions, queries.
