The rotating paddle type liquid level switch, as the “liquid level sentinel” of the silo, precisely monitors the upper limit, lower limit or specific liquid level of the materials through mechanical sensing. It can not only prevent material overflow or empty silos through alarms, but also achieve automatic control by联动ing equipment. At the same time， it is suitable for the characteristics of bulk solid materials and the complex environment of the silo. It is a key equipment for ensuring the safe operation of the silo and improving production efficiency.