bwerb,
A quick answer is...keep on drying your regulator that compressed air. You should keep in mind that if you direct the air into a wet first stage, you will still manage to get water into the works. You might want to direct the air at right angles to the orafice, creating a turbulent flow and a slight vacuum within the first stage opening (Bernouli's Effect).
High pressure can be used to penetrate the skin but this requires certain special circumstances. This is the principle behind auto injector devices. They however, usually require some sort of "seal" between the device and the skin. In fact, it is a high velocity fluid that cuts through the skin when accelerated through a very small opening.
These devices are injecting a fluid which has more mass than the propellant gas.
Technically, should any gas be injected simply under the skin, it is a gas emphysema. The amount used by these injection devices is very small and I truly don't know if any of the gas actually gets under the skin.
If a gas gets into the blood vessels, then it is an embolus. It is now free to travel in the blood stream to distant sites. Trouble occurs when the volume of the gas, as a bubble in circulation is sufficient to disrupt or prevent normal circulation in the affected site.
The organ, and its function also helps determine if a bubble of a particular size will cause a problem. Nervous tissue, by way of it's important functions and limited ability to regenerate would make such an injury more serious. Similarly, a bubble blocking the circulation to the heart muscle would be very serious.
A bubbles location, ie. on the venous side or the arterial side of heart also has some bearing on whether the bubble will do damage. I think that in general, an arterial bubble would be considered to be more dangerous.
Air can also be injected, theroretically, under the skin if it is directed at a break or wound in the skin. Again, an emphysema is the more likely, although very rare result. A relatively low pressure blast could cause a problem. This situation has been documented in the mouth when a dental air syringe (the blower thingy at the dentist) is directed into an extraction site, an incision site, or into an abscess.
It would take EXTREMELY high pressure air directed at an EXTREMELY small area to actually penetrate normal, undamaged skin. Even the air coming out of your tank is NOT at the internal pressure of the tank and it very rapidly expands from the time it leaves the valve to the time it hits an object. Attempting to seal the orafice with a finger will not cause the required resistance because the gas pressure will blow the obstruction off the orafice faster than it can build up sufficient pressure to "inject" the air.
IMHO the information your buddy shared with you is inaccurate or taken out of context.There may be occasions in medical literature in which a fatal injury was caused by a high pressure jet of air penetrating the skin--perhaps an industrial accident or explosion but I doubt that an injury like this has been attributed to drying a scuba regulator with air from the tank.
If there is a reference for such a DIVE injury, I would love to see it. In the event this has happened in the past, the common usage of an air blast in scuba WITHOUT injury is enough for me to "temp fate". Better yet, don't let your regulator get wet in the first place. Bleed the TANK for a moment to clear any water that has gotten into the valve stem.
Any water that has already gotten into the filter element of your first stage is already in there! An air blast will only remove the excess water from the exterior of the reg. Oh, yeah, when doing the air blast thing, it doen't require much skill to aim the air at the reg--with the fingers at the opposite end of the reg if you want to be more careful.
The preceding is my opinion and not to be used as medical fact. I really would love to see the reference to a dive injury caused by this procedure however.
Keep on puffin'.
Regards,
Larry Stein
