10
Valve connection to piping
The connections should be hand-tightened using PTFE (plumber’s tape) on the threads if using
the threaded connection type.
In case of heat welding (metal type connection), connection to the valve must not be carried out
during soldering.
Information
See chapter 3.4 to identify the connections. See page 16 for the description
and position of components.
Head valve installation
When pressurised, any composite tank will expand both vertically and in circumference. In order
to compensate for vertical expansion, the piping connections to the valve must be flexible enough
to avoid excessive stress on the valve and tank.
In addition, the valve and tank should not be supporting the weight of the piping, even partially.
The piping must therefore be fixed to a rigid structure (e.g. frame, skid, wall etc.) so that the weight
of it does not put any strain on the valve and the tank.
• The diagrams above illustrate how the flexible piping connections should be mounted.
• In order to adequately compensate for the elongation of the tank, the flexible pipes must be
installed horizontally.
• If the flexible piping connection is installed vertically, instead of compensating for the elongation,
it will create additional stresses on the valve-tank assembly. This must be avoided.
• The flexible piping connections must be suitably tight, thus preventing them from being
excessively long. For example, 20 - 40 cm is a suitable length.
• Excessively long and loose flexible piping connections will put the valve and tank assembly
under stress when the system is pressurised, as illustrated in the figure below: the assembly when
the system is unpressurised (shown on left), and the flexible piping connection when pressurised
tends to lift up the valve when stretching up (shown on the right). This configuration is even more
problematic when using semi-flexible piping.
• Insufficient vertical compensation may lead to various kinds of damage, either to the valve
thread which connects to the tank, or to the female thread connection on the tank which connects
to the valve. In some cases, there may be damage to the valve inlet and outlet connections.
200 mm flexible pipe
Wall-mounted
support
