As an apparatus to prevent the excess adsorption of oxygen molecules caused by excess supply of raw material air and the reduction in the level of generated oxygen caused by concentration of argon, which occur when a predetermined value of an oxygen supply flow rate is in a low flow rate zone, to suppress the electric power consumption and to stably drive a compressor, the present invention provides an oxygen concentrator that is a pressure swing adsorption-type oxygen concentrator equipped with at least one adsorption bed filled with an adsorbent capable of selectively adsorbing nitrogen relative to oxygen, an air supply device to supply compressed air to the adsorption bed, a flow channel switching device to repeat at a predetermined timing an adsorption step to supply air from the air supply device to the adsorption bed to isolate concentrated oxygen and a desorption step to depressurize the adsorption bed to regenerate the adsorbent therein, and a flow rate setting device to set a volume of concentrated oxygen supplied to a user comprising an exhaust pipe channel equipped with a leak valve in a flow channel between the air supply device and the adsorption bed to release a part of compressed air that is to be supplied to the adsorption bed into atmosphere.本發明提供一種壓力變動吸附型氧濃縮裝置作為可防止當氧供給流量之設定值為低流量範圍時,伴隨原料空氣供給過多產生之氧分子之過度吸附、伴隨氬濃縮產生之生成氧濃度降低,且可抑制耗費電力,並可實現壓縮機之穩定驅動之裝置,該氧濃縮裝置包含有填充有可優先選擇吸附氮而非氧之吸附劑之至少1個吸附床、將加壓空氣供給至該吸附床之空氣供給機構、以預定時序反覆進行將來自該空氣供給機構之空氣供給至前述吸附床,以取出濃縮氧之吸附步驟及將該吸附床減壓,使吸附劑再生之解吸步驟之流路切換機構及設定將濃縮氧供給至使用者之供給量之流量設定機構;於該空氣供給機構與該吸附床之流路間具有設置將供給至該吸附床之加壓空氣之一部份排出至大氣中之排出閥的排氣管路。501...外部空氣取入過濾器503...壓縮機504...切換閥505A...吸附筒505B...吸附筒507...製品槽509...流量設定機構512...加濕器a1...雙向閥a2...雙向閥b1...雙向閥b2...雙向閥
