This invention is drawn to a brush which cleans dust and debris from refrigeration coils in conventional coolers. When the door is opened, a cable draws a brush upwardly across the face of the condenser coil and removes dust from the coil. The brush is attached to a jointed arm which controls the positioning of the brush and keeps the brush contiguous the coil. A method of operating the device is also disclosed.
A self dust-off apparatus includes a fan and a controller. The fan, which can be driven to rotate clockwise or counterclockwise, is installed in a projector. The controller is employed to direct the rotational direction (clockwise or counterclockwise) of the fan. In the normal operation, the fan rotates to guide the air from an inlet to an outlet. In the dust-off operation, the fan rotates along reverse direction to guide air inversely in relation to the normal operation so that dust is taken out of the projector easily.