HDPE Electrofusion Process

A number of locations throughout the new irrigation system call for electrofusion branch saddles rather than a butt fusion tee.  An example of one of these locations would be a feed for a tee complex.  Electrofusion saddles are used in these locations to create a branch off of the mainline without cutting the pipe.  This cuts down on the number of welds needed to create each branch.  

Electrofusion is a method of joining HDPE pipe with special fittings that contain built in electric heating coils which are used to weld the joint together. A Friatec Friamat Fusion Unit is used to electrically heat the heating coils. 

Friamat Fusion Unit

The process of electrofusion welding begins by locating where the fitting is to be welded.  This location is then marked and the fitting is removed.  The surface of the pipe is now scored using a special scraper, exposing virgin material.  This process is key for proper electrofusion.  Next, the scored surface of the pipe and the surface of the fitting are cleaned using a using a lint free rag and oil free cleaner. The fitting is then placed in the location of the weld and strapped securely to the pipe.  

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HDPE pipe is scored and cleaned.

The electrofusion saddle is then strapped securely to the pipe.

Once the fitting is strapped to the pipe, electric leads from Friamat unit are connected to the connection points on either side of the fitting.  The bar code on the fitting is then scanned, telling the Friamat Unit exactly how long the heating process must last.  Voltage is then applied to the heating coils for the specified amount of time. The built in heating coils then melt the inside of the fitting and the outside of the pipe wall, which weld together producing a very strong homogeneous joint.  After the weld is complete, the weld cools for a specified time depending on the fitting.  The weld is then signed and dated.

Leads are connected and barcode is scanned.

Welding in progress.

Completed weld is signed and dated.

When the weld is completely cooled, a special hole saw is used to remove the section of pipe in the center of the branch.  This special bit makes sure to retract the section of pipe being removed.  A small vacuum can now be used to remove any left of over filings from the drilling process.  Once all of these steps have been completed, HDPE pipe can be butt fused directly onto the end of the branch saddle.