Patent classifications
B28B21/58
Pre-stressed concrete pipe
A pre-stressed concrete pipe is made by casting a concrete pipe inside a metal cylinder and then being pre-stressed by injecting solidifying compound under pressure into the boundary between the metal cylinder and concrete pipe, and includes a pair of end rings within the metal cylinder, each having a metal ring with an annular groove and an elastic band having a curved end to provide a rounded corner on the concrete pipe. After the solidifying compound is solidified, the concrete pipe retains the compression increasing its strength to withstand pressure, and moments caused by external loads. The pre-stressed concrete pipe further includes a bell ring mounted at one end and a spigot ring having a gasket ring at the other end. A bell clamp is mounted on the bell ring.
Liner for concrete article
The liner includes a rib formation with a transverse section configured to mechanically lock the liner to a concrete shell and a joint to allow the rib formation to flex. The joint for the rib formation can comprise a first side spaced apart from a second side with each joined to the transverse section to allow each side to flex with respect to each other. The space between the first side and the second side can be filled with a weld material to add rigidity to the rib formation while allowing it to flex. Each of the first side and the second side can be combined at the other end to a shell. The combined rib formation and shell are spirally wound to create the liner.
Liner for concrete article
The liner includes a rib formation with a transverse section configured to mechanically lock the liner to a concrete shell and a joint to allow the rib formation to flex. The joint for the rib formation can comprise a first side spaced apart from a second side with each joined to the transverse section to allow each side to flex with respect to each other. The space between the first side and the second side can be filled with a weld material to add rigidity to the rib formation while allowing it to flex. Each of the first side and the second side can be combined at the other end to a shell. The combined rib formation and shell are spirally wound to create the liner.