In a process for treating viscous products, especially for performing polymerization processes, especially for homo- or copolymerizing thermoplastics and elastomers, wherein monomer andor catalysts andor initiators are added to a backmixed mixing kneader, especially with a lengthdiameter ratio of 0. The upper and lower blocks, when joined together, have their discontinuous vessels connected to each other to complete a continuous vessel through which a thread is threaded. Accordingly, a hook method using the hooks of the lower end and a sheath assembling method of the upper end are used when assembling the support rods, thereby shortening assembly time and reducing labor cost, as well as effectively achieving the objective of improving productivity. The locking means is a ratcheting lock that releasably and ratchetingly engage teeth along an edge of the elongated bar.