Buderus Manual on Trenchless Installation of Ductile Cast ... - Duktus

2.3 Development in the joint-making techniques
When cast iron pipes first began to be used, one of the primary concerns was sealing
the individual butt joints between the pipes. In 172 , Jacob Leupold had already
described in his book [2.3] a mixture of various powders and substances containing
organic constituents to produce a sort of putty that was halfway elastic.
Fig. 2.13
Development in the joint-making techniques
In the period which saw the growth
of centralised systems of water supply
(18 0-1930), the cast iron pipes were fitted
with a socket that had to be packed;
it was sealed with tarred hanks of hemp
and poured lead (Fig. 2.13). When they
are being made, joints made with packed
sockets call for great skill and reliability on
the part of the fitters doing the job. Because
the sealing material is very inelastic,
Fig. 2.14
the joint must not be subject to any movements.
Bedding which will not be disturbed and support for the pipe which does not
allow any movement are essential for long-term freedom from leaks.
Rolling ring seals made of rubber were initially introduced for gas pipes in 18 0 and
from 18 3 on they came into use for water pipes. As from 1910 there were some initial
trial pipes in Stuttgart which used a precursor of the screw-gland socket joint but the
advantages of this joint were not appreciated for the time being. It only made its real
breakthrough in the early 1930‘s (Fig. 2.1 ) and in doing so it represented a milestone
in pipe-laying in that since then the elasticity of seals of vulcanised rubber has allowed
joints to move to a certain degree.
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