a reg to be more difficult to breath from when inverted and/or laying on your back face up? I noticed this on a cheap regulator and remember hearing something a time back, but can't remember the logic.
Otter
Otter
What are the physics that cause
- Thread starter Otter
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Face down the 2nd stage diaphragm senses a slightly higher pressure differential than you lungs are sensing...hence more air delivary, face up the diaphragm senses less pressure and therefore less air.
You can check if your reg is well tuned by immersing it in water mouthpiece up...if it starts to free flow before the moupiece is submerged...it's well tuned
You can check if your reg is well tuned by immersing it in water mouthpiece up...if it starts to free flow before the moupiece is submerged...it's well tuned
Gravity
But surely as gravity would tend to bring the diaphragm down whilst inverted, this would make breathing easier
For my money, cudachaser is on the mark.
Dom
Look at your diaphragm, then you'll get it. The effect cudachaser describes perfectly. The physical law is gravity.
Still don't get it.
Are you talking about gravity acting on the diaphragm or the pressure exerted by the water column as a result of gravity
Dom
I may be all wrong, but my understanding is that it is related to Boyle's law and the bouyancy of air.
When you are face down the regulator is below you. When the valve opens and air begins to flow it wants to go up, into your mouth. When you are on your back, the regulator is above you, so the air wants to stay in the regulator instead of flowing into your mouth. You have to inhale with the force needed to "pull" the air into your mouth, therefore you feel a greater breathing resistance.
When you are face down the regulator is below you. When the valve opens and air begins to flow it wants to go up, into your mouth. When you are on your back, the regulator is above you, so the air wants to stay in the regulator instead of flowing into your mouth. You have to inhale with the force needed to "pull" the air into your mouth, therefore you feel a greater breathing resistance.
Boyle's law does not, as I know it, have anything to do with the bouyancy of air. It has to do with gas compressibility at a given pressure and temperature.
I think that the bouyancy of air in a medium that has higher ambient pressure than 1 ata, such as we find when SCUBA diving, is the cause.
Simply put, when the regulator is below you the air will go up with no more effort than that required to crack the diaphragm, by the diver. In an upward position the air will collect at the top of the regulator, and additional effort, beyond cracking the diaphragm, will be required by the diver to overcome this buoyancy to inhale this air into his/her lungs.
ArizSig is right on the money, but Boyle's law, IMHO, has nothing to do with it.
i.e. The P1V1 when the regulator is located below the mouth, will be the same as the P2V2 if the regulator is located above the mouth, given the same temperature, of course. Temperature in this instance I believe will be negligible for most dives.
I think that the bouyancy of air in a medium that has higher ambient pressure than 1 ata, such as we find when SCUBA diving, is the cause.
Simply put, when the regulator is below you the air will go up with no more effort than that required to crack the diaphragm, by the diver. In an upward position the air will collect at the top of the regulator, and additional effort, beyond cracking the diaphragm, will be required by the diver to overcome this buoyancy to inhale this air into his/her lungs.
ArizSig is right on the money, but Boyle's law, IMHO, has nothing to do with it.
i.e. The P1V1 when the regulator is located below the mouth, will be the same as the P2V2 if the regulator is located above the mouth, given the same temperature, of course. Temperature in this instance I believe will be negligible for most dives.
Upon further reflection, I am siding with CudaChaser. And ArizSig!
Here's why: Air in it's natural state will avoid areas that have a higher pressure, preferring to exist in a state of equal pressure; it will move to areas of lower pressure to equalize the environment in which it is in. That is why we have wind!! That is air trying to equalize the surrounding environment.
Now, Air in a regulator below the mouth will more easily flow into your lungs because they have a lower pressure. Upside down, more effort is required to inhale the air, because you are bringing lower pressure air into a higher pressure environmet, (Your lungs).
Even given the minute distances involved, there exists a different P1V1 in your regulator than the P2V2 in your lungs. This means that reg below mouth easier breathing, and then the inverse is true with the reg above mouth, harder breathing.
Man, I hope I am right on this! I've never thought this much about it before, but it's good for me to know so that I can tell my students what's going on.
Opinions?
Here's why: Air in it's natural state will avoid areas that have a higher pressure, preferring to exist in a state of equal pressure; it will move to areas of lower pressure to equalize the environment in which it is in. That is why we have wind!! That is air trying to equalize the surrounding environment.
Now, Air in a regulator below the mouth will more easily flow into your lungs because they have a lower pressure. Upside down, more effort is required to inhale the air, because you are bringing lower pressure air into a higher pressure environmet, (Your lungs).
Even given the minute distances involved, there exists a different P1V1 in your regulator than the P2V2 in your lungs. This means that reg below mouth easier breathing, and then the inverse is true with the reg above mouth, harder breathing.
Man, I hope I am right on this! I've never thought this much about it before, but it's good for me to know so that I can tell my students what's going on.
Opinions?
Actually, both descriptions make sense to me now.
Shall we agree that it is a combination of gravity and gas laws?
Dom
Shall we agree that it is a combination of gravity and gas laws?
Dom
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