Pressurized tank and a device and method for feeding powder to a piping for conveying the powder

A pressurized tank is provided in which no air flows back from a piping for conveying powder to the pressurized tank. A pressurized tank (A) is used for a device (B) for intermittently feeding a predetermined amount of powder to a piping (7) for conveying the powder when the powder is conveyed in a plug flow through the piping (7) by means of compressed air. The tank (A) has a first pressurized room (6) that is a pressure vessel and that has a funnel-shaped upper partition (3) that has an opening and a funnel-shaped lower partition (4) that also has an opening, a first check valve (9) that is provided beneath the opening of the upper partition (3) of the first pressurized room (6) and is vertically moved so as to be upwardly moved by means of compressed air to close the opening of the upper partition (3), a second check valve (10) that is provided beneath the opening of the lower partition (4) of the first pressurized room (6) and is vertically moved so as to be upwardly moved by means of compressed air to close the opening of the lower partition (4), and an elastic body (24) to upwardly bias the second check valve (10).