JOINTS IN SEWERS
Sewer joints can be of the following types:
BELL AND SPIGOT JOINT: -
Such joints are quite common in plain or reinforced concrete pipes. Each pipe has a spigot end and a bell or socket end. Cement mortar of proportion 1:1 or 1:2 is inserted between the space of the bell end and spigot end. Gasket or jute packing may be placed in the inner side, to maintain alignment of the sewer.
COLLAR JOINTS: - For such a joint, the plain ends of the consecutive lengths of pipes are kept near each other and a collar of slightly bigger diameter is placed around the annular space between the collar and the ends of the pipes is then filled with cement mortar of 1:1 proportion.
SIMPLEX JOINT - Simplex joint, also known as ring rite coupling, is similar to collar joints, are used for asbestos cement pipes. The joint consist of a pipe sleeve or coupling of asbestos cement and two rubber rings which are compressed between exterior of the pipes and the interior of the sleeve.
FLEXIBLE OR BITUMINOUS JOINT: -The collar joints using cement mortar is relatively rigid. Such joints crack easily due to even slight movement of pipes due to settlement etc. these joints are made flexible by using bitumen or bituminous compounds instead of cement mortar.
MECHANICAL JOINT: - Such joints use mechanical devices like flanged rings, bolts, screwed ends to keep the two ends together. They are used for metallic sewers made of cast iron, steel etc.
