Using an air compressor to fill a scuba tank involves expensive equipment and the installation cost is high. It also requires a certain amount of training and expertise to complete the procedure. Around $5000 can be spent in getting the equipment and learning the procedure for filling up the tank so it is a steep investment. The safe and less expensive option is to get the tank filled by professionals. However, if you are still interested in doing it yourself, here’s the information you’ll need.
A scuba tank is made of aluminum or steel to hold air under pressure while diving. The cylinders are filled with nitrox, or a mixture of oxygen, nitrogen and helium. Custom air fills like the nitrox and the other mixtures need extra care and expertise to fill. Normally, scuba tanks can take air at a pressure of 3,000 pounds per square inch. Smaller cylinders are also available for different purposes.
Before filling a scuba tank, its rating should be known and the safety procedure should be followed, as cylinder explosions can cause fatalities. Safety precautions prescribed by the department of transportation should be strictly adhered to. Any cracks in the tank can compromise with the structural safety of the cylinder. The valve should be in a working condition and the insides of the tank should be checked for any corrosion, which might lead to failure of the cylinder. While not in use, the tanks/cylinders should be kept filled with around 250 lbs of air to avoid any moisture from seeping in.
Step 1 - Obtain Certification
Obtain a valid certification and expertise before filling any cylinders. Professional scuba inspector certification from DOT or OSHA or any other equivalent certification is necessary.
Step 2 - Check Tank Compliance
No out of compliance tanks should be filled. The hydrostatic testing dates should be thoroughly checked.
Step 3 - Bleed the Air
Remove/bleed air from the tank. Leave only up to 10 lbs of air inside the cylinder.
Step 4 - Check for Loose Objects
Listen for sounds from water and other loose objects inside the tank. Damaged and flooded tanks should be discarded.
Step 5 - Place the Tank in Cool Water
The cylinder should be placed in a tank with cool water to ensure the air is not expanded due to high temperature. This can also help point out cracks in tanks that look fine outwardly.
Step 6 - Inspect Filters and Gauges
The air compressor should be checked to see if it is in perfect working condition. The filters and gauges should be inspected.
Step 7 - Set up the Compressor
The air compressor needs to be set up to shut down automatically at the specified rating for the cylinder in use.
Step 8 - Attach the Yoke
The yoke of the compressor and the valve of the tank should be wiped clean. The yoke should be attached to the tank.
Step 9 - Fill the Cylinder
The cylinder valve should be opened completely and the compressor will start filling the cylinder.
Step 10 - Shut Down the Compressor and Disengage Yoke
The automatic shut down should be monitored meticulously and if it does not shut off automatically, it should be manually shut. Leaving the cylinder unattended can be dangerous. After the air is released, the yoke can be disengaged from the tank.