One of my teams has 2 separate pneumatics devices that are not connected in any way. We are currently debating interpretation of rule 26.
<26 b.> Pneumatic devices may be charged to a maximum of 100 psi.
Does this mean 100 total, or each device can have 100 psi meaning 200 total.
If it is 100 total, updating the manual to reflect a combined total of 100 would be helpful.
Thoughts?
If two cups of 50 degrees water are mixed together, the temperature will not become 100 degrees.
Each device has 100 psi meaning 100 psi total, air pressure does not stack.
Each device has 100ml meaning 200ml total, that how it works.
It 100psi. There is no such thing as “100 total” or whatever (unless you have a tank inside a tank, in which case let me know).
PSI is a unit of pressure. Atmospheric pressure is about 14psi (pounds per square inch), though this varies based on altitude and weather. In other words, the atmosphere is applying 14.7 pounds of pressure to every square inch of your skin. Fortunately, you’re used to this. When you’re on a plane, that pressure drops, and thats why your ears pop.
Air pressure is roughly linear with density, so if you take that normal atmospheric air and compress it to take up half the volume, it will exert an outward pressure of 29.4 PSI (absolute pressure) on the container, or a relative pressure of 14.7 PSI (or gauge pressure.) The difference in measurements is because the atmosphere pushes back on the outside of the container, so you subtract the atmospheric from the internal pressure being applied. This gauge pressure is what your pump reads out, and what the rule refers to.
Since air pressure is a measurement of the force exerted on the walls of the tank and not a unit of an amount of stuff, it isn’t really divisible across multiple things. You can’t have a “total” of 100 pounds per square inch by having 50 pounds per square inch across 2 tanks, you would just have 50psi if you did that. 100psi is just a regulation of what the max gauge pressure your tanks are allowed to hold is.
So yes you can have 100psi in every tank. Also many teams will link their tanks together, so they equalize pressure and can be filled from 1 nozzle.