What you guys are missing with the valve situation is we are working with air pressure. Since the air tanks are normally holding more pressure than the bag the air flows from the tank to the bag. Not because the valve is a one way valve, but because the pressure is greater on the tank side.
To understand this think of it this way. If your bags were filled to 80 pounds and your air tank was at 30 pounds the air would flow from the bag to the tank.....
