Clark tube

The utility model provides a Krah pipe, one end of the Krah pipe is a socket, the other end of the Krah pipe is a socket, a rubber ring is arranged on the socket, and a socket slope is arranged in thesocket; an outer groove for placing the outer groove rubber ring and an inner groove for placing the inner groove rubber ring are formed in the outer surface of the socket at intervals; and the outergroove is a step at the end part of the socket. The end part of an outer groove rubber ring is an inclined plane chamfer, the outer groove rubber ring is sleeved on a step at the end part of a socket, the inclined plane chamfer is propped against the front end of the socket, and inclined plane convex edges are arranged on the outer groove rubber ring at intervals; and inclined plane convex edgesare arranged on the inner groove rubber ring at intervals. The lubricating oil sleeve is convenient and fast to install and low in cost, and can be easily sleeved only by smearing lubricating oil; double-sealing-ring connection