… always amazes me.
I’ve been continuing my descent into the minutia of the engineering and technical details of pellet guns and the assorted peripherals and paraphernalia associated with the hobby.
One of the things I have been digging into is the whole concept of air pressure regulators. If you have extreme high pressure air in a bottle, you might think that it would require a highly complex system to deliver air at, say, ambient air pressure.
But that’s not the case. In fact it’s pretty simple. The first air regulators were created back in the eighteenth century, right after the first industrial air compressors were created. Originally created to deliver air to miners underground, they were quickly adapted to underwater breathing. In fact the initial design of air pressure regulators was so simple and so effective that they remained essentially unchanged until Jacques Cousteau revolutionized underwater exploration with his “self-contained underwater breathing apparatus” which we now know as “scuba gear.” Even then Cousteau’s modifications were relatively trivial and may even have been accomplished before Cousteau by a contemporary of Cousteau’s who was, unfortunately, killed in WWII.
So how does a regulator work? The simplest design is called a “one-stage regulator” and it essentially is nothing more than a small air reservoir attached directly to the high pressure air tank with a diaphragm on one side. The diaphragm is spring-loaded and is attached to a “poppet valve” which opens when the diaphragm is pushed TOWARD the high pressure tank, and closes when the diaphragm moves AWAY from the high pressure tank. A screw on the spring allows you to increase or decrease the load on the diaphragm so that more or less air enters the reservoir from the high pressure tank. A pressure gauge in the small reservoir tells you how much pressure it holds. Once you set the pressure using the screw, if you pull air out of the reservoir, the poppet valve will open, allowing more air from the high pressure tank, which will close the poppet valve.
It’s sheer brilliance really. And dirt simple. And highly reliable to boot.
If you need even more precision in your air pressure you can use a “two-stage regulator” which essentially creates two separate reservoirs so that the air pressure in the second reservoir does not jump up and down so much as the high pressure air enters the first reservoir. You can design this such that the “screw” is actually replaced with an ambient pressure device so that as you increase or decrease the external pressure, the regulated pressure automatically matches the outside pressure. This is the innovation that Cousteau added, and is why you can breathe at any depth using scuba tanks. The tanks deliver air at the ambient pressure, meaning that the deeper you dive, the higher pressure the air you breathe is. This is great until you reach the point that the pressure causes nitrogen to dissolve in your blood, but that’s a whole different discussion.
So, something so simple should be cheap right? Well, I suppose technically they are “cheap”. A regulator to control air pressure output on a high pressure tank costs about $120 or so, which isn’t that much. But after seeing how they are made, I can’t help but think that’s a lot of money for a valve, a diaphram, a spring and a screw….
Here’s a picture of a single stage regulator:
Seriously, I am sometimes amazed by how clever humans are.