Yes, hand held Fire Extinguishers for one.
You probably could fill it, but not to pressures needed for paintball gun operation, CO2 tanks should not be filled with any gas or liquid besides CO2. edit: you could use Argon in a HPA tank but not a CO2 tank
Yes, infact it is recommended.
A CO2 tank does not necessarily have to be upright. It depends if you want liquid CO2 or gaseous CO2. When I purchased a CO2 tank for a specific application, namely, CO2 snow cleaning, I had the option of getting a tank that either had a dipstick, that picked up liquid CO2 from the bottom of the tank, or one that had no dipstick so that it collected gas from the top of the tank. I selected a tank without the liquid pickup. So, my upright tank output gas. However, if I wanted liquid CO2, I would put my tank slightly upside down, and get liquid CO2. It is probably not recommended to run a commercial gas tank in a non-upright position. So, depending on what type of tank you have, and what type of output you want, the answer to your question literally is: depends. For farm and garden use, you are probably seeking gaseous output, and probably have a tank with no dipstick; based on these assumptions, yes, you will need to keep your tank upright.
Co2 (Carbon Dioxide) is NOT suitible for fire extenguishers. Co2 is a colorless, odorless, and deadly gas. There are alarms made for this. The most common contents of a fire extenguisher are foam and H2O (Water).
Yes, liquid CO2 has a wide use in industry as a solvent. It is used e.g. as a solvent for removing caffeine from coffee. It is liquid at -57oC and at about 5.2 bar. (about 80 psi).
If your gun is meant to run on CO2, then it will function well. If it is not, then it will jam up when the liquid gets insides until the gun completely jams up.
Some companies use the term to describe cryogenic liquid storage tanks.\One company provides:liquid oxygen (LOX),liquid nitrogen (LN, LIN),liquid argon (LAR)liquid carbon dioxide (CO2).
Their C02 is made from Dry Ice, and also from large tanker trucks of the same product. some larger restaurants use dry ice to make c02 also.
A CO2 fire extinguisher will work on flammable liquid and electrical fires only. If used on any other type of fire they will just give it more oxygen and it will spread.
Smart Parts claims it does, but you have to change settings, and even then you risk CO2 bleeding into the gun and damaging it.
They carry liquid oxygen with them in their capsule. CO2 is removed through filters. Don't ask where their drinking water comes from.
The CO2 or the dry Chemicals can be used to extinguish Liquid Fire, though other extinguishes can be used like halogen extinguishers, BUT the halogen is doesn't help as much as it harms, because it causes a toxic gas, and there is Foam extinguishers they come handy too.