home » How electrofusion pipes and PE fittings are performed

How electrofusion pipes and PE fittings are performed

46aa

Normal
0

21

false
false
false

ES
X-NONE
X-NONE

MicrosoftInternetExplorer4

st1:*{behavior:url(#ieooui) }

/* Style Definitions */
table.MsoNormalTable
{mso-style-name:”Tabla normal”;
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-priority:99;
mso-style-qformat:yes;
mso-style-parent:””;
mso-padding-alt:0cm 5.4pt 0cm 5.4pt;
mso-para-margin:0cm;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:”Calibri”,”sans-serif”;}
When a low tension electric current (from 8 to 48 V) is passed through the metal coils of electrowelding fittings, heating is produced (Joule Effect) that welds the pipe to the fitting.

Electrofusion is a joining system that is used to join pipes or pipes and medium or high-density PE, PE 80 and PE 100 Polyvalent or Fabricated Fittings. The electrowelding fittings can be used in pipes of SDR 17.6 for higher diameters of DN 90 and in pipes of SDR 11 for all diameters although every manufacturer must guarantee these ranges of SDR and DN.

They resist a 16 bar nominal pressure in water pipes and a 10 bar nominal pressure in gas pipes. In the market, there are electrowelding fittings of PN 25 bar. They usually are black or blue for water and black and yellow for gas and they are welded with a tension that varies from 8 to 42 volts according to the model although the most usual tension and which is more used nowadays by the manufacturers is 40 volts. The input of the welding data (voltage and fusion time) in the electrofusion machine, can be performed with manual machines or with machines whose fitting data are registered by reading its bar code through a light pen or scanner.

The welding fittings are provided with labels or magnetic cards in which there are bar codes where all the relevant information of the product appears there like fusion data. We will indicate below some steps to perform the electrofusion.  

Step 1: Preparation

During the transport, handling and laying of the PE pipes they could be damaged if it you are not careful enough.  It is allowed cuts and lines no higher than 10% of the thickness of the wall in water pipes and 5% in gas pipes. Clean the joining area of the pipe with a cloth or paper towel that doesn’t leave dirt.

Step 2: Scrap

To secure a good joint, the area of the surface of the pipe to be welded must be scraped to eliminate impurities, dirt, grease, etc. that could contaminate the welding. The length to be scraped must be marked with a felt tip and it must be used a rotary scraper. For tapping saddles, it can be used a manual scraper.

46bDon’t touch the scraped surface !

Step 3: Aligners

The MOST important part of the electrofusion process, is making sure that the pipes have not movement and be aligned during the heating and cooling phases. If the pipe moves during the cooling phase, the formed joint will fail. The aligners help to perform a good joint, avoiding the movement of the pipes.

Normal
0

21

false
false
false

ES
X-NONE
X-NONE

MicrosoftInternetExplorer4

46c

/* Style Definitions */
table.MsoNormalTable
{mso-style-name:”Tabla normal”;
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-priority:99;
mso-style-qformat:yes;
mso-style-parent:””;
mso-padding-alt:0cm 5.4pt 0cm 5.4pt;
mso-para-margin:0cm;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:”Calibri”,”sans-serif”;}
Step 4: Welding

The fittings are welded with an electrofusion welding machine (EF), which can be manual or automatic with a bar code or card lector.

        Connect the machine to a current supplier. 

        Follow the instructions of the screen and select Bar Code (for example).

        Plug the wire of the machine into the fitting and read the bar code. Start the welding.

        When finishing, allow it to cool before taking the aligner out.

Normal
0

21

false
false
false

ES
X-NONE
X-NONE

MicrosoftInternetExplorer4

46d

/* Style Definitions */
table.MsoNormalTable
{mso-style-name:”Tabla normal”;
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-priority:99;
mso-style-qformat:yes;
mso-style-parent:””;
mso-padding-alt:0cm 5.4pt 0cm 5.4pt;
mso-para-margin:0cm;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:”Calibri”,”sans-serif”;}
Step 5: Traceability

The traceability of the pipes buried in the ground is very important. The owners of gas and water networks must know what was welded and when and who did it.

        The EF machines use a Flash USB memory that allows us to transfer the data from a common programme of Windows like Excel.

46eStep 6: Reparation

If it is produced an escape in an old pipe, it is necessary to stop the flow to perform the reparation. This is performed with a tool called Squeeze-off.  There are ManualSqueeze-offs for pipes up to 110mm. From that diameter it is used Hydraulic Squeeze-offs.

46f

Normal
0

21

false
false
false

ES
X-NONE
X-NONE

MicrosoftInternetExplorer4

/* Style Definitions */
table.MsoNormalTable
{mso-style-name:”Tabla normal”;
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-priority:99;
mso-style-qformat:yes;
mso-style-parent:””;
mso-padding-alt:0cm 5.4pt 0cm 5.4pt;
mso-para-margin:0cm;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:”Calibri”,”sans-serif”;}

VERY IMPORTANT ! : It must be scraped the area of the pipe to be welded to take out  the dirt and the oxidation film produced by the oxygen of the air, on the contrary,  a wrong welding will be performed  and the joining will not  be stem or resistant to the internal pressure.

During the electrofusion process it is not required longitudinal movement of the pipe, therefore it is ideal to perform difficult installations, reparations and any other kind of subsequent operations to the installation like the performing of connections without taking out the pressure of the network by the tapping saddle.

The use of electrofusion for joining PE pipes or valves allows the installation of the buried homogeneous piping of the same material; it’s safe, economical and effective.

(Photos of the ADVANCE WELDING Company).

>>> If you have experience in electrofusion welding, you can share your opinion about that.

About the Author:

Leave A Comment