Sealer circulating system

A system for circulating a sealer, comprising:

• a circulation line in which a sealer is circulated;
• a first circulation valve disposed in the circulation line and configured to control the circulated sealer;
• a supply line branched from a front end of the first circulation valve;
• an applying gun disposed in the supply line and configured to receive the sealer and control the sealer discharged to the outside through a nozzle;
• a supply valve configured to control the sealer transferred to the applying gun in the supply line;
• a cylinder disposed between the supply valve and the applying gun and configured to pressure-feed the sealer to the applying gun;
• a discharge line, through which the sealer remaining after the injection from the applying gun is discharged, and which is joined to the circulation line;
• a second circulation valve configured to control the discharged sealer in the discharge line;
• a robot in which the applying gun is disposed at a front end of an arm of the robot;
• and
• a controller configured to operate the robot, the applying gun, the supply valve, the cylinder, the first circulation valve, and the second circulation valve, the system for circulating a sealer vary circulating direction in a continuous applying mode, a short-term pause mode and a long-term pause mode,
• wherein in the continuous applying mode, in which an applying operation continues for a predetermined period of time, the controller is configured to open the first circulation valve, open the supply valve, operate the cylinder, open an outlet of the applying gun, and close the second circulation valve.