REMS SSG 110/45 Instrucciones De Servicio página 8

eng
2. Preperations for use
2.1. Electrical connection
The butt welding unit must be connected to a socket with protective eart-
hing (earth conductor). Before connecting the unit, check to ensure that
the voltage given on the rating plate corresponds to the mains voltage.
2.2. Butt welder supporting stand
The unit is supplied complete with a supporting stand (1) as shown in
Fig.1. This serves as a steady during welding or as a support when the
unit is set aside. As an accessory, a clamp can be supplied for the work-
bench Fig. 2 (2), which can be used to secure the unit in a horizontal or
vertical position.
Caution! When the unit is hot, hold it only by the handle (3). Do not
touch the heating element (4) or the metal parts between the handle (3)
and heating element (4), otherwise a burn injury may result.
A plastic cover is available to protect the heating element in transit. This
must be removed without fail before the heating element is switched on
or, for transporting purposes, only after the heating element has cooled,
otherwise the cover will be destroyed and the unit damaged.
2.3. Electronic temperature control
According to DIN 15960 and DVS 2208, Part 1, the temperature of the
heating element should be capable of being adjusted in fine stages. In
order to ensure that the heating element operates at the required con-
stant temperature, these machines are equipped with a thermostat. DVS
2208, Part 1 specifies a maximum differential of 3°C between the preset
and actual temperatures. This degree of accuracy can be achieved only
by an electronic thermostat. For this reason welding machines opera-
ting at a fixed, preset temperature or employing a mechanical thermostat
may not be used for welding operations as described in DVS 2207.
The temperature can be adjusted on all REMS butt welders. They are
supplied with an electronic thermostat. The type of thermostat fitted is
identified on the welder rating plate by code letters, examples of which
are given below:
REMS SSG 180 EE: Adjustable temperature, electronic thermostat. The
preset temperature is adjusted to within ±1°C, i.e. with a preset tempe-
rature of 210°C (welding temperature for PE) the actual temperature will
fluctuate between 209°C and 211°C.
2.4. Preheating the butt welder
As soon as the connecting lead is connected to the mains, the welder
will begin to heat up. The red power-on indicator lamp (5) and the green
indicator lamp (6) light up. The unit requires about 10 minutes to heat
up.Once the required preset temperature is reached, the thermostat
installed in the unit cuts out the power supply to the heating element.
The red indicator lamp continues to glow. The green temperature indi-
cator lamp lights up intermittently, indicating the repeated switching on
and off of the power supply. After a further 10 minutes waiting time (DVS
2207, Part 1), welding operations can begin.
2.5. Selecting the correct welding temperature
The welder heating element is preadjusted to the average welding tem-
perature for PE-HD pipes (210°C). Depending on the pipe material and
the gauge of the pipe walls, it may be necessary to adjust this tempe-
rature. In this case, observe the manufacturer's information on the pipes
or mouldings without fail. Fig.3 contains a graph showing the guideline
temperatures for heating elements according to the gauge of the pipe
walls. In principle, the higher temperature should be used for thinner
walls and the lower temperature for thick walls, as far as possible (DVS
2207, Part 1). In addition, environmental influences (summer/winter)
may make it necessary to adjust the temperature. For this reason, the
temperature of the heating element should be checked, e.g. with an
electric surface thermometer. If necessary, the temperature can be adju-
sted by turning the temperature adjusting screw (7). In this case, it should
be remembered that the heating element must not be used until 10
minutes after the preset temperature has been reached.
3. Operation
3.1. Description of process
In the butt welding process, the contact faces of the two components
are matched together under pressure on each side of the heating ele-
ment, heated to welding temperature at reduced pressure, then joined
under pressure after the heating element has been withdrawn Fig. 4.
3.2. Preparations for welding
If the unit is used in the open air, care must be taken to ensure that wel-
ding will not be adversely affected by unfavourable environmental con-
ditions. In bad weather or strong sunlight, the welding position should
be covered, if necessary with an awning. To prevent the uncontrolled
cooling of the welding position by draughts, the welded pipe ends
should be enclosed. Out-of-round pipe ends must be trued up before
welding by e.g. carefully heating with a warm air heater. Only pipes or
pipes and mouldings of the same material and wall thickness may be
welded.
3.3. Preparation of pipe ends
Immediately before welding, the ends of the pipes must be suitably pre-
pared, i.e. cut off square and flat. This is performed with a REMS RAS
pipe cutter (see 1.1). If necessary, the welding faces must be cleaned
up with a knife or scraper. The gap between the parallel welding faces
must not exceed the width given in Fig. 5, or the displacement on the
outside of the pipes exceed 10% of the wall thickness.The welding faces
must not be touched again after preliminary processing before welding
takes place.
3.4. Process stages for butt welding
In the welding process, the joint faces are heated to welding tempera-
ture by the heating element, then welded together under pressure after
the heating element has been withdrawn. Before each welding process,
the temperature of the heating element in the welding area should be
checked. If necessary, it must be adjusted as described in 2.5. Also,
before each welding process, the heating element should be cleaned
with non-adherent paper or a non-fraying cloth and spirit or industrial
alcohol. In particular, no remnant of plastic must be left adhering to the
coating on the heating element. Also in the cleaning process, take care
to ensure that the anti-adhesive coating on the heating element is not
damaged by tools.
The process stages are shown in Fig. 6.
3.4.1. Adapting Process
In the adapting process, the joint faces are pressed against the heating
element until a bulge forms around each circumference. During this pro-
cess, a pressure of e.g. 0,15 N/mm
Part 1).
Depending on the diameter and wall thickness of the pipe, the requisite
degree of pressure must be calculated to ensure a adapting pressure
of 0,15 N/mm 2 at the joint faces. Pressure F is calculated from the pro-
duct of pressure p and pipe face area A (F = p · A), i.e. the greater the
pipe face area, the higher the pressure required. Thus, a pipe of e.g.
110 Nm diameter and PN 3,2 (s = 3,5 mm) gives a pipe face area of 1170
mm 2 and a requisite adapting pressure of F = 0,15 N/mm
175 N. The table in Fig. 7 indicates the pressure at which the pipe ends
should be pressed together. If pipes of greater diameter are to be welded,
a suitable alternative welder should be used.
The adapting process is concluded when a bulge, which is at least as
high as the figure given in Fig. 8, column 2, has formed around the entire
circumference of the pipe.
3.4.2. Heating
For the heating process, the pressure is reduced to almost zero. The
heating period is given in Fig. 8, column 3. During the heating process,
the heat penetrates into the joint faces, raising them to the necessary
welding temperature.
3.4.3. Changeover
After heating, the joint faces should be removed from the heating ele-
ment, which is then retracted without touching the heated faces. These
are then rapidly brought together until just before they touch. The time
taken for this process must not exceed the limit given in Fig. 8, column
4, otherwise the joint faces will cool to an impermissible extent.
3.4.4. Joining
The joint faces must be barely moving when brought into contact with
each other. The contact pressure should be steadily increased to 0.15
N/mm 2 and must be maintained during the cooling-off period Fig. 8,
eng
2 should be applied for PE (DVS 2207 ,
2 ·1170 mm 2 =