Single contrapuntal ascending and descending mechanism of tank truck steam cleaning machine

The utility model relates to a single contrapuntal ascending and descending mechanism of a tank truck steam cleaning machine. With the swift and violent development of the national economy in China, petroleum demand quantity is increased extremely; and with the development of the railway transportation industry, particularly, after trains are gradually speeded up, the quantity of petroleum products transported through the railway is gradually larger. The ascending and descending mechanism comprises an exhaust duct (1), wherein the exhaust duct is connected with a hydraulic valve group (2), one end of the exhaust duct is connected with a rotating mechanism (3), the other end of the exhaust duct is connected with an airtight cover (4) with an elastic sealing piece, the upper part of the airtight cover is connected with a steam pipe (12), the upper part of the exhaust duct is connected with a hydraulic cylinder (5), the exhaust duct is connected with a rotating handle (6), the hydraulic valve group is connected