Abstract: Considering certain deficiencies of traditional mechanical cleaning equipment and process of tanks, specific improvements are proposed. Firstly, the number is doubled to two tanks, to make the centrifugal pump operate under normal pressure at all times. Secondly, the nitrogen generator and the oxygen detector are linked to safely control the volume fraction of oxygen in the tanks. Thirdly, the oil-water separator is replaced with an automatic closed oil-skimming vessel to prevent the proliferation of oil and gas and reduce the labor intensity. Fourthly, the pneumatic valve is installed to avoid artificial switching of cleaner on the floating-roof of oil tank, with enhanced safety guarantee. Combining technical improvements and innovations of vacuum recovery, monitoring, skimming and switching of cleaner, the cleaning of sediment at tank bottom is directed towards an efficient, closed and automatic technique. This concept is worthy of extension and promotion.