A gas concentrator apparatus for supplying a gas to a patient and preventing leakage of the gas when a supply tube is removed from the gas concentrator apparatus includes a gas storage tank, a chamber, a piston, a membrane, a spring member, and the supply tube. The chamber is in gaseous communication with a gas storage tank for receiving the gas from the gas storage tank. The chamber comprises a piston configured to move the chamber in a forward direction or a reverse direction. The membrane is positioned at an end of the chamber distal to the gas storage tank. The membrane is actuated by a spring member to seal an entrance of the supply tube for preventing leakage of the gas when the supply tube is removed from the gas concentrator apparatus.
