Method and Equipment

                The experimental setup up for the determination of the Joule-Thomson coefficient is quite simple. Four gases were used, Argon, Nitrogen, Helium and Carbon dioxide. Each gas used was run three separate times. The gas tank of interest was attached to tubing that was connected to 100 feet of copper tubing. This tubing was connected to more tubing that traveled through an electronic pressure regulator and then connected to a glass chromatography column. The column was insulated with two layers of foam and a plastic tube to allow for the system to be adiabatic. This setup included 2 GLX apparatuses. One was to measure pressure and temperature at both ends of the chromatography column, and the other to control the pressure regulator. Each was configured with a computer using the program Data Studio.

                To begin the experiment, the system is first flushed out with the gas of interest. Then, the gas is allowed to leave the tank and travel through the series of tubing. The gas leaves the tank cold so, the copper tubing allows the gas to travel enough distance for it to reach room temperature. The gas is then passed through the glass chromatography column and is forced through the frit of the column. This frit serves as the obstacle. The gas therefore moves through an area of high pressure before the frit to an area of low pressure pass the frit. The end of the column pass the frit is open to the environment. The pressure on the side of the column before the frit is slowly increased using the pressure regulator. The temperature and pressure on each side of the frit are monitored and recorded using one of the GLX apparatuses. From the recorded data the Joule-Thomson coefficient can be calculated.