Compressed Gases

Changing Cylinders - Use of a Regulator - Safety Issues

Note: Now that the elevator is fixed, we're back to the standard procedure:

General Notes

    1. Cylinders must be stored and transported in a manner to prevent their falling. Escaping gas from a broken cylinder valve can propel a cylinder through a brick wall.
    2. Many gases are toxic and/or flammable. Knowing about the gas you are working with is as important as knowing about the reactants in your experiment. If you are not very familiar with the gas you plan to use, be sure to read its MSDS.
    3. Always use a cylinder cart to transport cylinders.
    4. Cylinders should be stored and moved with caps screwed in place. Cylinders and caps have either coarse threads or fine threads (it's easy to see); do not try to force a cap onto a cylinder with different threading.
    5. Cylinders must be chained or strapped to a bench, hood, or other sturdy object at all times. Do not attempt to use a cylinder cart as a securing device in the lab.
    6. Use the correct regulator for a particular gas; never attempt to used improvised adapters. When in doubt, ask someone who knows (me, Ken, or another research student who has experience).
    7. Electrically ground cylinders which contain flammable gases.

Procedure for Changing a Cylinder
    1. Obtain a full cylinder from Room 4136.  Do not, however, return empty cylinders back to the same room.
    2. Move the cylinder to your lab with a cylinder cart.
    3. Place the initials "THB", along with the current date, on the paper tag attached to the full cylinder.
    4. Remove the empty cylinder from the system (use a crescent wrench, not a pipe wrench, which roughens the edges of the nut) and replace the cap.
    5. Install the new cylinder.
    6. Take the capped, empty cylinder to the holding area across the hallway from the third floor Chemistry Department Stockroom, room 3409; leave it there on the cart. Notify stockroom personnel of its presence.

Procedure for Dispensing a Compressed Gas

Please ask an experienced researcher to accompany you the first time you do this!

    1. After the cylinder has been secured with a safety clamp, remove the cap and screw on the pressure regulator using a crescent wrench. Do not over-tighten the regulator!!
    2. Make sure the flow control valve (the needle valve on the outlet side of the regulator) is closed (clockwise, finger tight) and the delivery pressure screw ( the screw that delivers pressure from one side of the regulator to the other) is closed (counterclockwise until it feels loose). Both gauges should read zero.
    3. Open (counterclockwise) the main valve at the top of the gas cylinder fully by hand. The cylinder pressure gauge will now register the cylinder pressure.
    4. Turn the delivery pressure adjusting screw clockwise until the desired reading on the delivery pressure gauge is reached.
    5. The flow rate can now be adjusted using the flow control valve.
    6. Shut off the gas supply by closing the valves in the same order in which they were opened. Shut off the main tank first and allow the residual compressed gas in the valves to escape. When the gauges read zero, shut the delivery pressure screw and the flow control valve.