The invention discloses a rotary separating valve. The rotary separating valve comprises an upper casing, wherein a separating static sheet is arranged in the upper casing, a
nitrogen exhausting opening is formed in the center of the separating static sheet, a rotating movable sheet is arranged on the separating static sheet, and a
nitrogen exhausting passage is formed in the rotating movable sheet; one end of the
nitrogen exhausting passage communicates with a molecular
tower, and the other end of the nitrogen exhausting passage communicates with the nitrogen exhausting opening; an only-out-no-in one-way valve is arranged at the nitrogen exhausting opening. The invention discloses a method for prolonging the service life of an
oxygen generator. The rotary separating valve is mounted in the
oxygen generator, when a
machine does not work, the one-way valve has a sealing effect, so that greasy
dirt and humid air in the outside cannot enter a nitrogen storing cavity and the molecular
tower through the nitrogen exhausting opening to be in contact with a
molecular sieve, the service life of the
molecular sieve is prolonged, and further the service life of the
oxygen generator is prolonged; when the
machine works, the one-way valve is opened, the nitrogen exhausting function of the
machine is met, and sealing and nitrogen exhausting functions can be realized at the same time. The rotary separating valve and the method for prolonging the service life of the oxygen generator disclosed by the invention have the advantages that the rotary separating valve is simple in structure and ingenious in conception, and the service life of the oxygen generator is effectively prolonged.