Refilling Co2 Cylinders

Co2 cylinders are high pressured compressed gas cylinders containing carbon dioxide. Carbon dioxide, which is a combination of two molecules of oxygen and one of carbon, is a gas which exists in the air around us. It is the main gas that humans exhale and is often used in vineyards where, when introduced to the bottom of wine containers or floated on top of grape juice or wine, it forms a blanket of gas that will eventually purge the air space from the bottom up. This occurs due to the heavy nature of the gas and slow release, (reduces mixing), of Co2 gas from the solid state. Co2 cylinders are used to transport and store carbon dioxide.

Refilling Co2 Cylinders Is The Better Option

Co2 cylinders are expensive to hire, exchange or buy new and thus, in an effort to curb costs, the option to refill co2 cylinders is becoming very desirable. In that way, used cylinders can be utilized over and over, thus bypassing the extra cost of purchasing or hiring new cylinders. Safety guidelines related to gas cylinder storage must always be adhered to. This will avoid many unnecessary accidents.

Precautions To Take

However, refilling gas cylinders can be dangerous due to the high pressure contained and co2 cylinders are no exception. Before attempting to refill cylinders, people are urged to order and read pamphlets on the topic. Two recommended pieces of reading material include:

  • The G-6.3 (Carbon Dioxide Cylinder Filling and Handling Procedures For Beverage Plants, NSDA TD01)
  • The P-1 (Safe Handling of Compressed Gasses in Containers) from the Compressed Gas Association

Steps To Refilling Your Cylinder

  • When refilling a carbon dioxide cylinder, you need to make sure that both of the ball valves are closed and then fully depress the CA adaptor pin.

  • Inspect the O-Ring on your CA bottle before attaching the bottle to the CA adaptor. Replace if necessary.

  • Attach the bottle to the CA adaptor by screwing it in as you would screw the bottle into a gun. Screw in the CA adaptors pin and depress.

  • You should hear and feel the fill station's hose charge with some of the left over air in your CA tank.

  • Following this process you should open the second ball valve slowly. If you have a couple of ounces of air left in your CA tank you will be able to cool the tank while you drain it. Drain your bottle completely.

  • Do not attempt to fill a partially full bottle. You should also ensure that your cylinder is completely cool.

  • Place your cylinder on a scale, which will help you judge the fullness as it fills up.

  • Open the bulk cylinder's main valve, if not already open. Turn on ball valve number one completely.

  • Watch the scale and close valve #1 when the scale reads 1 to .5 ounces under the bottle's capacity, which will ensure it is not over filled.

  • Close the bulk cylinder's main valve and unscrew the CA adaptor pin depress until it is completely disengaged.

  • Open valve number 2 to drain the compressed CO2 still in the hose and finally unscrew your newly filled tank from the CA adaptor.

Remember to keep compressed air safety guidelines in mind when working with these cylinders.

Co2 cylinders can be bulky and cumbersome to transport. When on the move, equipment like Hobart's portable co2 cylinder kit can be a good alternative to the full sized cylinder filled up above. Hobart claims a full CO2 cylinder will provide roughly 40 minutes of continuous arc time on mild steel. The kit can be mounted on Hobart's Handler 140, 187, and 210 models, and also can be adapted to fit many other popular MIG welders.