With the rapid development of relevant industries in our country, the demand for the transportation of liquid products is increasing. The transportation industry of liquid products via tank trucks by rail or road is expanding rapidly. However, due to the特殊性 of the transported products, the empty-running rate is often very high, which affects economic benefits. To reduce the empty-running rate and enhance economic efficiency, it is necessary to clean the tank trucks before reloading with other types of materials.