Elevatable chamber and method of operating the same

An elevatable chamber comprising:

• a chamber body constituted by a lower body and an upper body located above the lower body;
• a chamber frame comprising a pair of vertical frames located so as to face each other with the chamber body disposed therebetween, a horizontal frame connecting upper parts of the pair of vertical frames to each other, and a support plate located under the horizontal frame and configured to move upwards and downwards with the upper body fastened thereto;
• an air cylinder comprising a cylinder tube having a cylindrical shape located in the vicinity of each of the pair of vertical frames, a head cover configured to seal a head-side end of the cylinder tube and having a head-side port configured to allow air to be introduced therethrough when the support plate is moved upwards and to allow air to be exhausted therethrough when the support plate is moved downwards, a rod cover configured to seal a rod shaft end of the cylinder tube and having a rod-side port configured to remain open, a piston configured to divide a cylinder chamber of the cylinder tube, and a piston rod having one side connected to the piston and the other end connected to the support plate;
• and
• a controller comprising a supply pressure control member configured to supply air to the cylinder tube such that the support plate is moved upwards, a first pressure sensor located in front of the supply pressure control member, a pair of supply flow sensors located in front of the first pressure sensor, a pair of exhaust flow sensors configured to exhaust air from the cylinder tube when the support plate is moved downwards, a second pressure sensor located in front of the exhaust flow sensors, and an exhaust pressure control member located in front of the second pressure sensor,
• wherein the exhaust pressure control member performs control such that air in the cylinder tube is exhausted while being maintained at a predetermined pressure.