An apparatus includes a sprinkler configured for spraying liquid and a member with a nano-coating surface. The nano-coating surface is configured to receive liquid sprayed from the sprinkler. The apparatus further includes a sensor associated with the member and the sensor is configured to detect a signal directly or indirectly corresponding to a film deposition on the nano-coating surface. Moreover, the apparatus has a controller coupled with the sensor and the sprinkler, wherein the signal detected by the sensor is transmitted to the controller and the controller is configured to command the sprinkler spraying liquid on the nano-coating surface while a value of the signal reaches a threshold value.