Polyfusion - Butt welding. Flexalen PB Polybutene pipes

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Francis Hamilton
5 years ago
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1 Polyfusion - Butt welding Flexalen PB Polybutene pipes

2 POLYFUSION BUTT WELDING PROCESS This technique is reserved to specially trained welders, since utmost precision and considerable experience are indispensable for the achievement of impeccable weld joints. The welding equipment comprises: A clamping tool, mostly with hydraulic control A thermostatically controlled welding tool A facer for the pipe-end faces In choosing the clamping tool and machine size, note that on insulated pipes the jacket pipe, too, may project into the welding machine and thus determine machine size. Important note on the connection of fittings: For the fittings in our product range, only clamping devices with extremely narrow welding jaws can be used, such as are normally used in internal piping systems (machine tools). Note the following important technical data: After facing the remaining gap must in no place exceed 0.5mm Pipe misalignment must not exceed 10% of the pipe wall thickness The welding temperature is C +/- 10 C Min. / Max. ambient temperature 0 C / +40 C The setting pressure for matching and joining (=moving tool pressure + matching and joining pressure) should be determined in accordance with the directions for use of the welding machine

PRE-TREATMENT OF SURFACES TO BE WELDED (1) Pipes and fittings should be clamped

cleanser for Polyolefin plastic pipes (PB, PP, PE).

3 PRE-TREATMENT OF SURFACES TO BE WELDED (1) Pipes and fittings should be clamped and aligned in the clamping device so that the surfaces to be welded are plane-parallel. Mobility along the longitudinal axis should be safeguarded by appropriate measures (e.g. adjustable dollies). (2) After clamping, the pipe ends to be welded should be simultaneously treated with the facer. Then remove the chips. Make sure that the treated faces are neither dirty nor chamfered, or else they should be planed once again. (3) Deburring the pipe ends if necessary and clean the faces of the pipe ends with cleanser for Polyolefin plastic pipes (PB, PP, PE). (4) Test plane-parallel mounting and alignment by moving the faces together. (5) Before starting the welding process, determine the matching and joining pressure and check the surface temperature as well as the condition of the welding tool, which must be free from dirt and mechanical damage. clamp and align check use facer remove chips deburr clean

THE WELDING PROCESS (1) Place the heating element between the parts to be welded and press the surfaces together with specific matching pressure.

(2) Immediately after matching (bead of 1mm), reduce pressure and apply heat for the duration of the required warm-up time.

4 THE WELDING PROCESS (1) Place the heating element between the parts to be welded and press the surfaces together with specific matching pressure. Continue matching until a bead of 1mm height has formed. (2) Immediately after matching (bead of 1mm), reduce pressure and apply heat for the duration of the required warm-up time. (3) Resetting phase detach surfaces from heating element and remove the latter. (4) Join the heated surfaces, increasing the pressure steadily to the required level. (5) Allow the welding parts to cool off, maintaining the pressure throughout the cooling-off time. (6) Check the weld by visual inspection of the welding seam/the bead. matching join, cool off, check

5 PARAMETERS FOR BUTT FUSION WELDING OF PB PIPES Reference values for butt welding with heating element of Polybutene pipes at 20 C outside temperature and moderate wind. 1N=0.102 kp t1 = bead formation, heating time under pressure t2 = heat up time under reduced pressure t3 = dwell time / removal of heating device t4 = bead formation time under pressure t5 = cooling time under a constant pressure Ambient temperature + 5 C to +40 C Heating element temperature C ± 10 C CAUTION! The required pressures for all butt welding equipments have to be calculated according to these parameters. The absolute pressure (bar) is related to the construction of the machine.

6 QUALITY CHECK The quality of a welding could be checked over the weld bead width. Bead width Pipe [mm] dimension max. OD x s [mm] min x x x x x 20.4 According to DVS 2202 Remark: This instruction is applicable for the welded connection of Polybutene pipes with oxygen diffusion barrier and for the welded connection of fittings made of Polybutene using the polyfusion welding technique. For the execution of welding work on Polybutene pipes and components only persons should be used, that are trained (in accordance to DVS guideline 2207 or compareable) in the relevant welding technique. The used devises have to apply to the DVS guideline (DVS 2208 part 1/2). In addition all welding defects, as described in the guideline of the DVS (DVS 2202 part 1), are to be avoided. Special attention has to be paid to the maximum angular deviation. 04/2015

buttfusion jointing compatibility ambient conditions welding operations 0,2-1,4 g/10 min (190 C 5 Kg) -5 C and +40 C

buttfusion jointing compatibility ambient conditions welding operations 0,2-1,4 g/10 min (190 C 5 Kg) -5 C and +40 C 30 buttfusion jointing UNI 10520 is the correct reference standard for the carrying out of the buttfusion jointing. With this process the surfaces to be welded are heated by contact with an heating element