A novel gas lift apparatus is described which is particularly useful for the dewatering of gas wells in which the gas pressure is low or for the lifting of oil from wells when mixed oil and gas are produced. Water or oil is allowed to collect in the tubing above the valve of the apparatus. Sensors provide...http://www.google.de/patents/US4596516?utm_source=gb-gplus-sharePatent US4596516 - Gas lift apparatus having condition responsive gas inlet valve
