A method and a device for preventing repeated refreshing of an address table of an Ethernet ring network node are provided. The distortion adjustment value calculation portion decreases the distortion adjustment value in accordance with a generation situation of the input image, so that the degree of the correction in the distortion correction process by the distortion correction processing portion is decreased. The base pipe comprises a plurality of flow restriction elements arranged in a selected pattern along the base pipe to provide a desired distribution of the fluid flowing into or out of the sand screen. The cooling system incorporating gas blower, 3-phases induction motor MD is actuated by the blower motor contactor SD.