Flinn and Price XXXXXXXXXXinvestigated the separation of mixtures of argon and helium in a continuous-flow electrical glow-discharge device. The apparatus used is shown in Fig. 1. The principle of...

Flinn and Price (1966) investigated the separation of mixtures of argon and helium in a continuous-flow electrical glow-discharge device. The apparatus used is shown in Fig. 1. The principle of separation is the the gases will font positive ions within the glow discharge, and the species with the lower ionization potential (argon) should migrate preferentially, to the cathode. in the apparatus shown in Fig. 1a luminous glow discharge is formed between a tubular aluminum positively charged anode and a tubular aluminum negatively charged cathode. The mixture of helium and argon enters continuously midway along the discharge path. There are two gas exit streams, one near each electrode. Valves in the exit gas lines are adjusted so that exactly half the feed gas (on a molar basis) leaves in each exit stream. The device is run at low pressures, with the pressure level monitored by a Dubrovin gauge. Table 1 shows the separation factors found experimentally for argon-helium-mixtures at 0.67 kPa (5 mm Hg) as a function of feed composition, discharge current and flow rate. Suggest physical reasons why the separation factor a) decreases with increasing feed flow rate. b) increases with increasing discharge current, and c) decreases with increasing argon mole fraction in the feed.10 cm 1.4 35 cm8 mm I.D. To Dubrovin - gauge70 cm10 cm6 mm 1.D. 8 mm I.D. t 12 cm Exit gas InIet gas Exit gas 1\-riAnode chamber I i I / Cathode Tungsten wire chamber 35 mm 1.D. --4-cm cmFigure 1 Continuous-flow Glow-discharge Separation DeviceTo main vacuum