SYGEF Product Catalogue

Approximate values for butt fusion of PVDF¹)
Wall
thickness
(mm)
Equalisation
at
p=0.10
N/mm²
Height
of bead
(mm)
Heating
time ²)
p=0.01
N/mm²
(sec)
Changeover
to
Time
time reach
max. full
(sec) jointing
(sec)
Cooling
time ²)
under
jointing
p=0.10
N/mm²
(min)
1.9 .. 3.5 0.5 59 .. 75 3 3 .. 4 5 .. 6
3.5 .. 5.5 0.5 75 .. 95 3 4 .. 5 6 .. 8.5
5.5 .. 10.0 0.5 .. 95 .. 140 4 5 .. 7 8.5 .. 14
1.0
10.0 ..
15.0
1.0 ..
1.3
140 ..
190
4 7 .. 9 14 .. 19
15.0 ..
20.0
20.0 ..
25.0
1.3 ..
1.7
1.7 ..
2.0
190 ..
240
240 ..
290
1) in accordance with DVS 2207-15
5 9 .. 11 19 .. 25
5 11 .. 13 25 .. 32
2) The times are affected by the pipe wall thickness, the
outside temperature and wind strength.
Determine the values to be set for equalisation and
jointing on the basis of the information above, bearing in
mind the instructions from the manufacturer of the fusion
jointing machine before commencing the fusion process.
Fusion jointing procedure
Once it has attained the fusion temperature, position the
heating element in the fusion jointing machine. Press the
parts to be joined against the heating element with the
force required for equalisation until the entire
circumference of each of the jointing faces rests
completely against it and a bead (see the table) has
formed. Reduce the equalisation pressure almost to 0 (p
~ 0.01 N/mm²). The heating time listed in the table is
measured from this moment.
exceed the value listed in the table. Pay particular
attention during jointing that the parts be moved together
swiftly until the surfaces are about to touch.
Then they should be moved together so that they are in
contact along the entire circumference. Next the
pressure should be increased rapidly to the present
jointing pressure within the period of time specified in the
table. This pressure must be maintained during the entire
cooling period. Adjustment may be necessary, especially
shortly after the jointing pressure has been attained.
The jointed parts must stay in the fusion jointing machine
under jointing pressure until the end of the cooling period
specified in the table.
Join and cool
Leave parts in the fusion jointing machine at fusion
pressure until the end of the cooling period!
Once the heating period has elapsed, remove the parts
from the heating element which should then be removed
without touching the jointing surfaces and push the parts
together immediately. The changeover time must not
Fusion check
A bead should form around the entire circumference of
the pipe. K in the diagram to the left should always be
positive.
Carrying out the pressure test
All fusion joints must be allowed to cool completely
before pressure testing, i. e. as a rule wait about 1 hour
after the last joint has been completed.
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