5.2.4 Connection of several tanks
Two or more tanks are connected via the assembly
surfaces by means of GRAF special seals DN 100 and
basic pipes (to be provided at construction site).
The apertures must be drilled to the corresponding size
using only the GRAF special crown bit. It must be ensured
that the distance between the tanks is at least 600 mm.
The pipes must project 100 mm - 150 mm into the tanks.
5.3
Insertion and filling
The tank must be inserted, impact-free, into the prepared
trench using suitable equipment. The tank is filled with
approx. 25 cm water before filling the tank surround.
Afterwards the surrounding (roundgrain gravel, max.
grain size 8/16) is then filled in layers of max. 40 cm
steps and is compacted.
The individual layers must be well-compacted (manuel
tamper). Damage to the tank must be avoided during
compaction. Mechanical compaction machines must not
be used under any circumstances. The surrounding must
be at least 500 mm wide.
5.4
Routing connections
All feed and overflow pipes must be routed with a decline
of at least 1% in the direction of flow (possible, subsequent
settling must be taken into consideration in this case).
All suction, pressure and control lines must be routed in an
empty pipe, which must be routed as straight as possible,
without bending, to the tank with a decline. Necessary
bends must be formed using 30° moulded sections.
Important: The empty pipe must be connected to an
aperture above the max. water level.
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5.
Installation and assembly
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